Wave attenuation stents

Abstract

An implant for improving blood flow through a patient's vasculature is described. The implant includes a first compliant stent sized for placement in a first blood vessel, wherein the first stent has a first major axis and a first minor axis. The implant also preferably includes a second compliant stent sized for placement in a second blood vessel branching from the first blood vessel, wherein the second stent has a second major axis and a second minor axis. The second stent is preferably rotationally offset relative to the first stent for attenuating pressure waves in the patient's vasculature.

Description

Docket No.: ADV-23439WO01 WAVE ATTENUATION STENTS RELATED APPLICATION(S)

[0001] This application claims the benefit of U.S. Provisional Application Serial No.63 / 604,800, filed on November 30, 2023, which is hereby incorporated by reference in its entirety. BACKGROUND

[0002] The present disclosure generally relates to the field of implantable medical devices. Stiffened walls in the pulmonary vasculature may generate backflow wave reflections directed upstream (e.g., towards the right ventricle). SUMMARY

[0003] Described herein are devices, methods, and systems that facilitate attenuation of wave reflections. Devices associated with the various examples of the present disclosure can include stents designed to cyclically reshape a target blood vessel segment in a manner as to affect blood flow therein. Such stents, and / or portions thereof, can be configured to transition between circular and non-circular (e.g., oval) shapes for the purpose of changing the volume of the target blood vessel segment. Such stents can have coverings, shapes, and / or other features that may promote efficient reshaping of the target blood vessel and / or hemostatic sealing between the stent and the blood vessel wall.

[0004] In some aspects, the techniques described herein relate to an implant system including: a first stent disposed in a first blood vessel, the first stent having a first major axis and a first minor axis, wherein the first major axis is larger than the first minor axis; and a second stent disposed in a second blood vessel that branches from the first blood vessel, the second stent having a second major axis and a second minor axis, wherein the second major axis is larger than the second minor axis, wherein the second stent is rotationally offset relative to the first stent.

[0005] In some aspects, the techniques described herein relate to a system, wherein the first major axis is rotationally offset relative to the second major axis.

[0006] In some aspects, the techniques described herein relate to a system, further including a third stent disposed in a third blood vessel that branches from the first blood vessel, wherein the third stent is rotationally offset relative to the first stent.Docket No.: ADV-23439WO01

[0007] In some aspects, the techniques described herein relate to a system, wherein the third stent is rotationally offset relative to the second stent.

[0008] In some aspects, the techniques described herein relate to a system, wherein the first stent has an oval shape.

[0009] In some aspects, the techniques described herein relate to a system, wherein the first stent has a peanut shape.

[0010] In some aspects, the techniques described herein relate to a system, wherein the first stent includes a network of struts forming cells, and wherein the cells have varying sizes.

[0011] In some aspects, the techniques described herein relate to an implant system including: a first stent disposed in a first blood vessel, the first stent having a first major axis and a first minor axis, wherein the first major axis is larger than the first minor axis, wherein the first stent includes a network of struts forming cells, and wherein the cells have varying sizes.

[0012] In some aspects, the techniques described herein relate to a system, wherein the cells increase in size along a length of the first stent.

[0013] In some aspects, the techniques described herein relate to a system, wherein the first stent includes a first portion, a second portion, and a third portion arranged in series along a length of the first stent, and wherein cells of the second portion are larger than cells of the first portion.

[0014] In some aspects, the techniques described herein relate to a system, wherein cells of the third portion are larger than cells of the second portion.

[0015] In some aspects, the techniques described herein relate to a system, wherein the first stent increases in width along a length of the first stent.

[0016] In some aspects, the techniques described herein relate to a system, wherein the first stent includes a first portion, a second portion, and a third portion arranged in series along a length of the first stent, and wherein the second portion has a greater width than the first portion.

[0017] In some aspects, the techniques described herein relate to a system, wherein the third portion has a greater width than the second portion.

[0018] In some aspects, the techniques described herein relate to a system, wherein cells of the second portion are larger than cells of the first portion.Docket No.: ADV-23439WO01

[0019] In some aspects, the techniques described herein relate to a system, wherein the width of the first stent increases gradually between a first end of the first stent and a second end of the first stent.

[0020] In some aspects, the techniques described herein relate to a system, wherein the width of the first stent increases in a stepwise manner.

[0021] In some aspects, the techniques described herein relate to a method including percutaneously delivering a first stent to a first blood vessel, wherein the first stent has a first major axis and a first minor axis, and wherein the first major axis is larger than the first minor axis.

[0022] In some aspects, the techniques described herein relate to a method, further including percutaneously delivering a second stent to a second blood vessel, wherein the second blood vessel branches from the first blood vessel, and wherein the second stent is rotationally offset relative to the first stent.

[0023] In some aspects, the techniques described herein relate to a method, further including percutaneously delivering a third stent to a third blood vessel, wherein the third blood vessel branches from the first blood vessel, and wherein the third stent is rotationally offset relative to the first stent.

[0024] For purposes of summarizing the disclosure, certain aspects, advantages, and novel features have been described. It is to be understood that not necessarily all such advantages may be achieved in accordance with any particular example. Thus, the disclosed examples may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other advantages as may be taught or suggested herein.

[0025] Methods and structures disclosed herein for treating a patient also encompass analogous methods and structures performed on or placed on a simulated patient, which is useful, for example, for training; for demonstration; for procedure and / or device development; and the like. The simulated patient can be physical, virtual, or a combination of physical and virtual. A simulation can include a simulation of all or a portion of a patient, for example, an entire body, a portion of a body (e.g., thorax), a system (e.g., cardiovascular system), an organ (e.g., heart), or any combination thereof. Physical elements can be natural, including human or animal cadavers, or portions thereof; synthetic; or any combination of natural and synthetic. Virtual elements can be entirely in silica or overlaid on one or more of the physical components. Virtual elements can be presented on any combination of screens,Docket No.: ADV-23439WO01 headsets, holographically, projected, loudspeakers, headphones, pressure transducers, temperature transducers, or using any combination of suitable technologies.

[0026] Any of the various systems, devices, apparatuses, etc. in this disclosure can be sterilized (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.) to ensure they are safe for use with patients, and the methods herein can comprise sterilization of the associated system, device, apparatus, etc. (e.g., with heat, radiation, ethylene oxide, hydrogen peroxide, etc.). BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Various examples are depicted in the accompanying drawings for illustrative purposes and should in no way be interpreted as limiting the scope of the inventions. In addition, various features of different disclosed examples can be combined to form additional examples, which are part of this disclosure. Throughout the drawings, reference numbers may be reused to indicate correspondence between reference elements.

[0028] Figure 1 illustrates example cardiac and vascular anatomy of a patient having a healthy, compliant aorta.

[0029] Figures 2A and 2B show side and axial cross-sectional views, respectively, of the healthy aorta of Figure 1 experiencing compliant expansion.

[0030] Figure 3 shows an example stiff aorta.

[0031] Figures 4A and 4B show side and axial cross-sectional views, respectively, of the stiff aorta of Figure 3 experiencing compromised expansion.

[0032] Figures 5-1 and 5-2 show a blood vessel in circular and non-circular shapes, respectively.

[0033] Figures 6A-6D show perspective, side, and axial views, respectively, of a non-circular stent in accordance with one or more examples.

[0034] Figure 7 shows an axial view of an uncovered, non-circular stent deployed within a blood vessel in accordance with one or more examples.

[0035] Figures 8A and 8B show perspective and axial views, respectively, of a non-circular stent having an outer covering in accordance with one or more examples.

[0036] Figure 9 illustrates an example implant system for modifying pulmonary waves in accordance with one or more examples.

[0037] Figure 10 illustrates another example implant system for modifying pulmonary waves in accordance with one or more examples.Docket No.: ADV-23439WO01

[0038] Figures 11A and 11B illustrate an example oval-shaped stent for modifying pulmonary waves in accordance with one or more examples.

[0039] Figures 12A and 12B illustrate an example peanut-shaped stent for modifying pulmonary waves in accordance with one or more examples.

[0040] Figures 13A and 13B illustrate an example oval-shaped stent for modifying pulmonary waves in accordance with one or more examples.

[0041] Figures 14A and 14B illustrate an example oval-shaped stent for modifying pulmonary waves in accordance with one or more examples.

[0042] Figure 15 provides a flowchart illustrating an example process for delivering one or more stents as described in one or more examples herein.

[0043] Figure 16 illustrates an example implant for modifying pulmonary waves in accordance with one or more examples. DETAILED DESCRIPTION

[0044] The headings provided herein are for convenience only and do not necessarily affect the scope or meaning of the claimed invention.

[0045] Although certain preferred examples are disclosed below, it should be understood that the inventive subject matter extends beyond the specifically disclosed examples to other alternative examples and / or uses and to modifications and equivalents thereof. Thus, the scope of the claims that may arise here from is not limited by any of the particular examples described below. For example, in any method or process disclosed herein, the acts or operations of the method or process may be performed in any suitable sequence and are not necessarily limited to any particular disclosed sequence. Various operations may be described as multiple discrete operations in turn, in a manner that may be helpful in understanding certain examples; however, the order of description should not be construed to imply that these operations are order dependent. Additionally, the structures, systems, and / or devices described herein may be embodied as integrated components or as separate components. For purposes of comparing various examples, certain aspects and advantages of these examples are described. Not necessarily all such aspects or advantages are achieved by any particular example. Thus, for example, various examples may be carried out in a manner that achieves or optimizes one advantage or group of advantages as taught herein without necessarily achieving other aspects or advantages as may also be taught or suggested herein.Docket No.: ADV-23439WO01

[0046] Certain reference numbers are re-used across different figures of the figure set of the present disclosure as a matter of convenience for devices, components, systems, features, and / or modules having features that may be similar in one or more respects. However, with respect to any of the examples disclosed herein, re-use of common reference numbers in the drawings does not necessarily indicate that such features, devices, components, or modules are identical or similar. Rather, one having ordinary skill in the art may be informed by context with respect to the degree to which usage of common reference numbers can imply similarity between referenced subject matter. Use of a particular reference number in the context of the description of a particular figure can be understood to relate to the identified device, component, aspect, feature, module, or system in that particular figure, and not necessarily to any devices, components, aspects, features, modules, or systems identified by the same reference number in another figure. Furthermore, aspects of separate figures identified with common reference numbers can be interpreted to share characteristics or to be entirely independent of one another.

[0047] Where an alphanumeric reference identifier is used that comprises a numeric portion and an alphabetic portion (e.g., ‘10a,’ ‘10’ is the numeric portion and ‘a’ is the alphabetic portion), references in the written description to only the numeric portion (e.g., ‘10’) may refer to any feature identified in the figures using such numeric portion (e.g., ‘10a,’ ‘10b,’ ‘10c,’ etc.), even where such features are identified with reference identifiers that concatenate the numeric portion thereof with one or more alphabetic characters (e.g., ‘a,’ ‘b,’ ‘c,’ etc.). That is, a reference in the present written description to a feature ‘10’ may be understood to refer to either an identified feature ‘10a’ in a particular figure of the present disclosure or to an identifier ‘10’ or ‘10b’ in the same figure or another figure, as an example.

[0048] Certain standard anatomical terms of location are used herein to refer to the anatomy of animals, and namely humans, with respect to various examples. Although certain spatially relative terms, such as “outer,” “inner,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” “top,” “bottom,” and similar terms, are used herein to describe a spatial relationship of one device / element or anatomical structure to another device / element or anatomical structure, it is understood that these terms are used herein for ease of description to describe the positional relationship between element(s) / structures(s), as illustrated in the drawings. It should be understood that spatially relative terms are intended to encompass different orientations of the element(s) / structures(s), in use or operation, in addition to the orientations depicted in the drawings. For example, an element / structure described as “above” another element / structure may represent a position that is below orDocket No.: ADV-23439WO01 beside such other element / structure with respect to alternate orientations of the subject patient or element / structure, and vice-versa. It should be understood that spatially relative terms, including those listed above, may be understood relative to a respective illustrated orientation of a referenced figure. Vascular Anatomy and Compliance

[0049] Certain examples are disclosed herein in the context of vascular implant devices, and in particular, compliance-enhancing stent implant devices implanted / implantable in the aorta. However, although certain principles disclosed herein may be particularly applicable to the anatomy of the aorta, it should be understood that compliance-enhancement implant devices in accordance with the present disclosure may be implanted in, or configured for implantation in, any suitable or desirable blood vessels or other anatomy, such as the inferior vena cava.

[0050] The anatomy of the heart and vascular system is described below to assist in the understanding of certain inventive concepts disclosed herein. In humans and other vertebrate animals, the heart generally comprises a muscular organ having four pumping chambers, wherein the flow thereof is at least partially controlled by various heart valves, namely, the aortic, mitral (or bicuspid), tricuspid, and pulmonary valves. The valves may be configured to open and close in response to a pressure gradient present during various stages of the cardiac cycle (e.g., relaxation and contraction) to at least partially control the flow of blood to a respective region of the heart and / or to blood vessels (e.g., ventricles, pulmonary artery, aorta, etc.). The contraction of the various heart muscles may be prompted by signals generated by the electrical system of the heart.

[0051] Figure 1 illustrates an example representation of a heart 1 and associated vasculature having various features relevant to one or more examples of the present inventive disclosure. The heart 1 includes four chambers, namely the left atrium 2, the left ventricle 3, the right ventricle 4, and the right atrium 5. In terms of blood flow, blood generally flows from the right ventricle 4 into the pulmonary artery via the pulmonary valve 9, which separates the right ventricle 4 from the pulmonary artery 11 and is configured to open during systole so that blood may be pumped toward the lungs and close during diastole to prevent blood from leaking back into the heart from the pulmonary artery 11. The pulmonary artery 11 carries deoxygenated blood from the right side of the heart to the lungs. The pulmonary artery 11 includes a pulmonary trunk and left and right pulmonary arteries that branch off of the pulmonary trunk, as shown.Docket No.: ADV-23439WO01

[0052] The tricuspid valve 8 separates the right atrium 5 from the right ventricle 4. The tricuspid valve 8 generally has three cusps / leaflets and may generally close during ventricular contraction (i.e., systole) and open during ventricular expansion (i.e., diastole). The mitral valve 6 generally has two cusps / leaflets and separates the left atrium 2 from the left ventricle 3. The mitral valve 6 is configured to open during diastole so that blood in the left atrium 2 can flow into the left ventricle 3, and, when functioning properly, closes during systole to prevent blood from leaking back into the left atrium 2. The aortic valve 7 separates the left ventricle 3 from the aorta 12. The aortic valve 7 is configured to open during systole to allow blood leaving the left ventricle 3 to enter the aorta 12, and close during diastole to prevent blood from leaking back into the left ventricle 3.

[0053] The heart valves may generally comprise a relatively dense fibrous ring, referred to herein as the annulus, as well as a plurality of leaflets or cusps attached to the annulus. Generally, the size of the leaflets or cusps may be such that when the heart contracts the resulting increased blood pressure produced within the corresponding heart chamber forces the leaflets at least partially open to allow flow from the heart chamber. As the pressure in the heart chamber subsides, the pressure in the subsequent chamber or blood vessel may become dominant and press back against the leaflets. As a result, the leaflets / cusps come in apposition to each other, thereby closing the flow passage. Disfunction of a heart valve and / or associated leaflets (e.g., pulmonary valve disfunction) can result in valve leakage and / or other health complications.

[0054] The atrioventricular (mitral and tricuspid) heart valves generally are coupled to a collection of chordae tendineae and papillary muscles (not shown for visual clarity) for securing the leaflets of the respective valves to promote and / or facilitate proper coaptation of the valve leaflets and prevent prolapse thereof. The papillary muscles, for example, may generally comprise finger-like projections from the ventricle wall. The valve leaflets are connected to the papillary muscles by the chordae tendineae. A wall of muscle 17, referred to as the septum, separates the left 2 and right 5 atria and the left 3 and right 4 ventricles.

[0055] The vasculature of the human body, which may be referred to as the circulatory system, cardiovascular system, or vascular system, contains a complex network of blood vessels with various structures and functions and includes various veins (venous system) and arteries (arterial system). Generally, arteries, such as the aorta 16, carry blood away from the heart, whereas veins, such as the inferior and superior venae cavae, carry blood back to the heart.Docket No.: ADV-23439WO01

[0056] The aorta 16 is a compliant arterial blood vessel that buffers and conducts pulsatile left ventricular output and contributes the largest component of total compliance of the arterial tree. The aorta 16 includes the ascending aorta 12, which begins at the opening of the aortic valve 7 in the left ventricle of the heart. The ascending aorta 12 and pulmonary trunk 11 twist around each other, causing the aorta 12 to start out posterior to the pulmonary trunk 11, but end by twisting to its right and anterior side. Among the various segments of the aorta 16, the ascending aorta 12 is relatively more frequently affected by aneurysms and dissections, often requiring open heart surgery to be repaired. The transition from ascending aorta 12 to aortic arch 13 is at the pericardial reflection on the aorta. At the root of the ascending aorta 12, the lumen has three small pockets between the cusps of the aortic valve and the wall of the aorta, which are called the aortic sinuses or the sinuses of Valsalva. The left aortic sinus contains the origin of the left coronary artery, and the right aortic sinus likewise gives rise to the right coronary artery. Together, these two arteries supply the heart.

[0057] As mentioned above, the aorta is coupled to the heart 1 via the aortic valve 7, which leads into the ascending aorta 12 and gives rise to the innominate artery 27, the left common carotid artery 28, and the left subclavian artery 26 along the aortic arch 13 before continuing as the descending thoracic aorta 14 and further the abdominal aorta 15. References herein to the aorta may be understood to refer to the ascending aorta 12 (also referred to as the “ascending thoracic aorta”), aortic arch 13, descending or thoracic aorta 14 (also referred to as the “descending thoracic aorta”), abdominal aorta 15, or other arterial (or venous) blood vessel or portion thereof.

[0058] Arteries, such as the aorta 16, may utilize blood vessel compliance (e.g., arterial compliance) to store and release energy through the stretching of blood vessel walls. The term “compliance” is used herein according to its broad and ordinary meaning, and may refer to the ability of an arterial blood vessel or prosthetic implant device to distend, expand, stretch, or otherwise deform in a manner as to increase in volume in response to increasing transmural pressure, and / or the tendency of a blood vessel (e.g., artery) or prosthetic implant device, or portion thereof, to recoil toward its original dimensions as transmural pressure decreases.

[0059] Arterial compliance facilitates perfusion of organs in the body with oxygenated blood from the heart. Generally, a healthy aorta and other major arteries in the body are at least partially elastic and compliant, such that they can act as a reservoir for blood, filling up with blood when the heart contracts during systole and continuing to generate pressure and push blood to the organs of the body during diastole. In olderDocket No.: ADV-23439WO01 individuals and patients suffering from heart failure and / or atherosclerosis, compliance of the aorta and other arteries can be diminished to some degree or lost. Such reduction in compliance can reduce the supply of blood to the organs of the body due to the decrease in blood flow during diastole. Among the risks associated with insufficient arterial compliance, a significant risk presented in such patients is a reduction in blood supply to the heart muscle itself. For example, during systole, generally little or no blood may flow in the coronary arteries and into the heart muscle due to the contraction of the heart which holds the heart at relatively high pressures. During diastole, the heart muscle generally relaxes and allows flow into the coronary arteries. Therefore, perfusion of the heart muscle relies on diastolic flow, and therefore on aortic / arterial compliance.

[0060] Insufficient perfusion of the heart muscle can lead to and / or be associated with heart failure. Heart failure is a clinical syndrome characterized by certain symptoms, including breathlessness, ankle swelling, fatigue, and others. Heart failure may be accompanied by certain signs, including elevated jugular venous pressure, pulmonary crackles, and peripheral edema, for example, which may be caused by structural and / or functional cardiac abnormality. Such conditions can result in reduced cardiac output and / or elevated intra-cardiac pressures at rest or during stress.

[0061] Figures 2A and 2B show side and axial cross-sectional views, respectively, of the healthy aorta 16 of Figure 1 experiencing compliant expansion and contraction over a cardiac cycle. Figure 3 shows an example stiff aorta 16’, whereas Figures 4A and 4B show side and axial cross-sectional views, respectively, of the stiff aorta 115’ of Figure 3 experiencing compromised expansion and contraction over a cardiac cycle.

[0062] The systolic phase of the cardiac cycle is associated with the pumping phase of the left ventricle, while the diastolic phase of the cardiac cycle is associated with the resting or filling phase of the left ventricle. As shown in Figures 2A and 2B, with proper arterial compliance, an increase in volume Δv will generally occur in an artery when the pressure in the artery is increased from diastole to systole. With respect to the aorta, as blood is pumped into the aorta 115 through the aortic valve 107, the pressure in the aorta increases and the diameter of at least a portion of the aorta expands. A first portion of the blood entering the aorta 115 during systole may pass through the aorta during the systolic phase, while a second portion (e.g., approximately half of the total blood volume) may be stored in the expanded volume Δv caused by compliant stretching of the blood vessel 115, thereby storing energy for contributing to perfusion during the diastolic phase. A compliant aorta mayDocket No.: ADV-23439WO01 generally stretch with each heartbeat, such that the diameter of at least a portion of the aorta expands.

[0063] The tendency of the arteries to stretch in response to pressure as a result of arterial compliance may have a significant effect on perfusion and / or blood pressure in some patients. For example, arteries with relatively higher compliance may be conditioned to more easily deform than lower-compliance arteries under the same pressure conditions. Compliance (C) may be calculated using the following equation, where Δv is the change in volume (e.g., in mL) of the blood vessel, and Δp is the pulse pressure from systole to diastole (e.g., in mmHg): ^^^^ ^^ (1)

[0064] Aortic stiffness and reduced compliance can lead to elevated systolic blood pressure, which can in turn lead to elevated intracardiac pressures, increased afterload, and / or other complications that can exacerbate heart failure. Aortic stiffness further can lead to reduced diastolic flow, which can lead to reduced coronary perfusion, decreased cardiac supply, and / or other complications that can likewise exacerbate heart failure.

[0065] Healthy arterial compliance may cause retraction / recoil of the blood vessel wall inward during diastole, thereby creating pressure in the blood vessel to cause blood to continue to be pushed through the artery 115 when the valve 107 is closed. For example, during systole, approximately 50% of the blood that enters the artery 115 through the valve 107 may be passed through the artery, whereas the remaining 50% may be stored in the artery, as enabled by expansion of the vessel wall. Some or all of the stored portion of blood in the artery 115 may be pushed through the artery by the contracting vessel wall during diastole. For patients experiencing arterial stiffness that causes lack of compliance, their arteries may not operate effectively in accordance with the expansion / contraction functionality shown in Figures 2A and 2B.

[0066] As shown in Figure 3, the aorta tends to change in shape as a function of age, resulting in a higher degree of curvature and / or tortuosity over time. As the vasculature of a subject becomes less elastic, arterial blood pressure (e.g., left-ventricular afterload) becomes more pulsatile, which can have a deleterious effect, such as the thickening of the left ventricle muscle and / or diastolic heart failure. Stiffness in the aorta and / or other blood vessel(s) can occur due to an increase in collagen content and / or a corresponding decrease in elastin. While stiff / non-compliant blood vessels can generally suffer from a lack of elasticity in the walls thereof, as shown as causing compromised / reduced stretching and volumeDocket No.: ADV-23439WO01 change Δv’, such vessels can maintain some amount of flexibility / bendability, such that reshaping of the blood vessels can occur without necessarily requiring the stretching of the walls of the blood vessel.

[0067] Generally, the majority of aortic compliance is provided in the ascending aorta 12 with respect to healthy anatomy. Furthermore, calcification frequently occurs in the area of the ascending aorta 12, near the aortic arch 13 and the great vessels emanating therefrom. Such anatomical areas can experience relatively higher stresses due to the geometry, elasticity, and flow dynamics associated therewith. Therefore, implantation and deployment of compliance-enhancing, non-circular stent implant devices of the present disclosure can advantageously be in the ascending aorta 12 in some cases. While relatively less calcification tends to occur in the descending 14 and abdominal 15 aorta, implant devices of the present disclosure can advantageously be implanted / deployed in such areas as well for the purpose of increasing compliance in the aortic system. Examples of the present disclosure provide compliance-enhancing stent implant devices, which may be implanted in one or more locations in a compromised aorta and / or other vessel(s). For example, Figure 3 shows example positions of stent devices 101 including features disclosed herein implanted in various areas of an aorta 16’. Compliance-Enhancing Stent Implants

[0068] The present disclosure relates to systems, devices, and methods for adding- back and / or increasing compliance in the aorta or other arterial (or venous) blood vessel(s) to provide improved perfusion of the heart muscle and / or other organ(s) of the body. Examples of the present disclosure can include stents that, when implanted, are configured to decrease the cross-sectional area / volume of the blood vessel segment in which the stent is implanted during low-pressure conditions, such as diastole, which serves to force blood through the blood vessel segment by pushing the blood through the vessel as the vessel volume reduces in connection with stent contraction induced by cyclical drops in blood pressure.

[0069] The non-circular (e.g., oval- and / or peanut-shaped) stents of the present disclosure can advantageously be configured to generate a differential cross-sectional area or volume of the target blood vessel(s) (e.g., aorta) between high- and low-pressure phases of the cardiac cycle to facilitate perfusion. As described above, relatively non-compliant blood vessels generally may not be able to stretch to thereby lengthen the perimeter of the blood vessel in response to increased pressure conditions. Such inability to stretch can prevent compliant expansion of the blood vessel.Docket No.: ADV-23439WO01

[0070] As the stents of the present disclosure produce complaint blood vessel volume change by manipulating / reshaping the native blood vessel walls, compliance can be increased in the target blood vessel without requiring blood vessel grafting or resection. Therefore, compared to blood flow solutions involving blood vessel grafting / resection, examples of the present disclosure can provide a solution that avoids the risks that may be associated with cutting of the vessel and / or devices grafted in / to such vessels, which may present risk of rupture and blood leakage outside of the circulatory system. Hazards associated with extravascular arterial blood leakage, such as within the abdominal and / or chest cavity, can include the risk of serious injury or death.

[0071] As described above, desirable diastolic flow in arterial (or venous) blood vessels is enabled by the decrease in cross-sectional area / volume of the blood vessels when transitioning from higher pressure conditions (e.g., systole) to lower pressure conditions (e.g., diastole). Where the relevant blood vessel has become stiff and non-compliant, stretching / expanding and subsequent contraction / shrinking of the blood vessel to cause the desired change in area / volume of the blood vessel may be limited due to the perimeter / wall of the blood vessel being resistant to stretching. Examples of the present disclosure provide implants that cause a change in cross-sectional area / volume of a target blood vessel without requiring stretching in the blood vessel wall. Rather, such cyclical change in blood vessel area / volume can be achieved through manipulation of the shape (e.g., cross-sectional shape) of the target blood vessel, wherein a transition between blood vessel shapes occurring in response to changing pressure conditions can reduce and increase the area / volume of the blood vessel in a cyclical manner to promote more even flow of blood through the blood vessel throughout the cardiac cycle.

[0072] With respect to a blood vessel having a relatively fixed perimeter, wherein the blood vessel wall 502 does not expand sufficiently due to stiffness and / or other factors of non-compliance, generally, the greatest area / volume of the blood vessel may be present / achieved when the blood vessel wall 502 forms a circular cross-sectional shape, which may maximize the cross-sectional area and volume of the blood vessel. Figure 5-1 shows an example blood vessel 501 (identified as blood vessel 501a in Figure 5-1) having a generally circular cross-sectional shape, such that the area Acthereof is maximized for the given perimeter / wall-length Pa. In the circular configuration, the diameter d1 is substantially constant at every angle about the axis of the vessel.

[0073] Diverging from a circular cross-sectional shape can produce a cross- sectional area / volume for a blood vessel that is less than the maximum area Acshown inDocket No.: ADV-23439WO01 Figure 5-1. For example, Figure 5-2 shows the blood vessel 501 (identified as vessel 501b in Figure 5-2) having a shape that resembles an oval / ellipse, which produces the cross-sectional area Aothat is less than the area Acwith the same blood vessel wall / perimeter length Pa. The oval shape of the vessel 501b may have a major axis amhaving a dimension d3that is greater than a dimension d2 of the minor axis an thereof.

[0074] With further reference to Figures 5-1 and 5-2, due to the area Aoof the oval vessel of Figure 5-1 being less than the area Ac of the circular configuration shown in Figure 5-1, transitioning from the circular shape 501a to the non-circular shape 501b, can provide a reduction in area / volume of the blood vessel, and therefore solutions that cause transitions between circular and non-circular blood vessel shapes between cardiac phases can provide compliance characteristics without the need for elasticity in the blood vessel wall tissue. For example, where a mechanism is implemented to cause a blood vessel to transition between circular and non-circular shapes in response to changing pressure conditions, such manipulation of the blood vessel shape can introduce volumetric change in the blood vessel in response to the typical changes in pressure experienced during the cardiac cycle, thereby increasing cardiac efficiency and reducing pulsatile load.

[0075] In view of the foregoing, examples of the present disclosure provide stent implant devices and associated processes configured to transition the shape / area of a blood vessel from circular / more-circular to non-circular / less-circular shapes, and vice versa, to enhance compliance with respect to the area of the implant reshaping. Such stent implant devices / processes may affect vessel reshaping through dynamic reshaping of the structural shape of the stent in a way that produces a change in shape of the blood vessel in which it is implanted to produce a change in blood vessel area / volume between the systolic and diastolic phases of the cardiac cycle. As described above, for relatively stiff blood vessels, radial outward expansion / stretching of the blood vessel sufficient to achieve a change in volume that produces desirable compliance may not occur as pressure conditions change. Using stent implant devices in accordance with aspects of the present disclosure may be desirable to provide the necessary change in volume of the target blood vessel.

[0076] Examples of the present disclosure provide for stent-type implants that are biased to a non-circular cross-sectional area, such that, in a relaxed / non-pressurized state, a first diameter of the stent has a greater dimension along a major axis compared to a second diameter of the stent along a minor axis, wherein such stents are configured to transition to a more-circular shape when pressure within the blood vessel overcomes the non-circular bias of the stent and causes the stent walls to be pushed to the more-circular configuration. TheDocket No.: ADV-23439WO01 ability of stent implant devices of the present disclosure to reshape the target blood vessel in the manner described above to produce the desired oval cross-section of the blood vessel can be achievable due to stiff / non-compliant blood vessels, which may be unable to stretch to a substantial degree, still retaining the ability to bend to a sufficient degree to allow for such shaping of the blood vessel. That is, the bending stiffness of a non-compliant blood vessel may be relatively lower compared to the stretching stiffness thereof. Therefore, examples of the present disclosure achieve compliance through bending energy with respect to the blood vessel wall, as opposed to stretching energy. When stents of the present disclosure are forced to a circular, or relatively more-circular, axial cross-sectional shape, energy may be stored in the shape memory of the walls of the stent, wherein recoil / contraction of the stent towards its biased, oval / non-circular configuration can return / release energy to the blood circulation.

[0077] In some examples, a stent and / or similar device may provide an added compliance (i.e., added change in volume over a constant change in pressure) to any blood vessel in or on which it is placed. The term “stent” is used herein in accordance with its broad and ordinary meaning and may refer to any device configured to be implanted in a lumen of a blood vessel, the device having a tubular form forming a lumen through which blood can flow. Pulmonary Wave Modification

[0078] The present disclosure relates to systems, devices, and methods for pulmonary wave modification. For instance, the present disclosure relates to implant devices and associated implantation methods for modifying pulmonary waves. According to certain aspects, implant devices according to the present disclosure can be configured to modify pulmonary waves, which can include forward waves and backward reflection waves. For example, forward waves and / or backward reflection waves in pulmonary arteries (or pulmonary vessels) can be modified to reduce interference between the forward waves and the backward reflection waves. In some cases, an implant system can include multiple devices positioned in different vessels and / or chambers and / or in series in a single vessel and / or chamber. The multiple devices can have different shapes and / or sizes and / or can be positioned at different angles relative to each other.

[0079] Implant devices according to the present disclosure can reduce the impact of backwards reflection waves to reduce pulsatile loading and therefore RV afterload in order to preserve RV function. For instance, reducing the interference between the forward waves and the backward reflection waves can reduce pulmonary pressure and RV afterload. TheDocket No.: ADV-23439WO01 implant devices according to the present disclosure may be applicable across multiple types of pulmonary hypertensive conditions. According to certain aspects, backward waves in pulmonary arteries (e.g., flowing toward the pulmonary valve 9) may be referred to as “backward(s) compression waves,” “return reflected waves,” “backward(s) reflected / reflection waves,” or “backward(s) waves.” Forward waves in pulmonary arteries (e.g., flowing away from the pulmonary valve 9) may be referred to as “forward compression waves” or “forward waves.”

[0080] Implant devices according to the present disclosure can include various configurations that promote diversion, convergence, deflection, and / or cancellation of pulmonary waves. For example, implant devices can be configured to divert, converge, deflect, and / or cancel forward waves or backward waves or both in order to minimize the interference of the forward waves and the backward waves. For instance, the implant devices can reduce the impedance and fluid energy loss that occur when forward waves and backward waves that were previously in different phases of the cardiac cycle interact due to both now occurring during systole. By mitigating the wave interference, the resistance to forward flow is reduced, thereby decreasing RV work. Pulmonary pressure and RV afterload can be reduced by reducing the interference between the forward waves and the backward waves. Such approach can reduce RV afterload without requiring modification of the pulmonary microcirculation that determines pulmonary vascular resistance or left atrial pressures. A secondary benefit can be promotion of fluid shear across the luminal surface, which improves vessel reactivity and flow-mediated vasodilation. Various examples and implementations that modify pulmonary waves can be applicable across various circulations and diseases, including but not limited to arterial hypertension and coronary vascular disease. Features described with respect to various examples and implementations of the implant devices according to the present disclosure can be independently implemented. Wave Modification Implants

[0081] Figures 6A–6D show perspective, minor-axis side, major-axis side, and axial views, respectively, of a non-circular stent 600 in accordance with one or more examples. The stent may be deployable within a blood vessel lumen. However, it should be understood that example stent devices of the present disclosure may alternatively or additionally be deployable in a position around an outer surface of a target blood vessel. Although not shows for clarity in the figures of the present disclosure, it should be understood that example stents described herein may comprise one or more hooks, barbs,Docket No.: ADV-23439WO01 and / or other attachment features / means adapted to facilitate secure attachment of the stent to the tissue of the target blood vessel wall. The description of the stent 600 may be understood to relate to, and / or describe aspects of, any of the stents described herein; that is, description of aspects of any example stent of the present disclosure may be understood to be implementable in any other example stent of the present disclosure.

[0082] The stent 600, as with other stents disclosed herein, may be formed of a tubular frame 631, which may form a wall around an axial channel 649, thereby defining the channel 649. The stent 600 may be an elongate / elongated stent, in that a length L of the stent is greater than a maximum diameter dmaj of the stent. As described herein, the frame wall 631 of the stent 600 can be considered a circumferentially wrapped wall, or may beconsidered to comprise multiple or wall segments. For example, with respect to oval stents and other non-circular stents, as illustrated in Figures 6A–6D, such stents may be considered to comprise sidewall segments 625 that run along relatively long sides of the stent that are aligned generally with the orientation of the major axis / dimension Amaj of the stent, as well as end wall segments 627, which may connect the side walls 625 on major-axis ends of the stent 600. The end walls 627 may be outwardly curved / concave with respect to an axis As of the stent 600. In some examples, a tangent line associated with a vertex Ve of the end wall(s) 627 may align in parallel with the minor axis / dimension Amin of the stent 600. The sidewalls 625 may be generally straight over at least a portiona length thereof, and / or may bow / deflect inward and / or outward, either in a resting, unpressurized state, or in conditions of hoop / wall stress on the frame 631. For example, the sidewalls 625 may bow outward such that the sidewalls 625 are concave from the perspective of the axis As of the stent 600 and convex from the perspective of the exterior of the stent 600, wherein the sidewalls 625 form a vertex Vs, which may be aligned with the minor axis / dimension Amin of the stent 600.

[0083] Certain stent shapes are described herein, including non-circular-, oval-, peanut-, and other-shaped stents. It should be understood that such description of stent shapes refers to a shape of an axial cross-section of a stent, as depicted in the view of Figure 6D. Although oval- and peanut-shaped stents are described, it should be understood that the principles of the present disclosure may relate to stents having any non-circular shape in at least some configurations thereof (e.g., relaxed configuration). Descriptions of stents in a relaxed configuration should be understood to relate to a configuration that a stent naturally assumes in the absence of tension on the stent wall(s) from external forces (e.g., ambient fluid pressure, physical contact forces, etc.).Docket No.: ADV-23439WO01

[0084] The stent 600 may be considered an oval stent with respect to the shape of the axial cross-section thereof, as shown in Figure 6D. The term “oval” is used herein according to its broad and ordinary meaning and may be used substantially interchangeably with the term “ellipse” and / or “oblong,” which terms are likewise used according to their broad and ordinary meanings. The term “oval” may be used to refer to any non-circular closed curve having major and minor axes, the major axis being greater than the minor axis. With respect to “oval”-shaped stents disclosed herein, such stents may have relatively flatter minor-axis sidewalls (compared to curved major-axis end walls), wherein the sidewalls may bow radially outward, and / or may be deflected / curved radially inward so as to produce external concavity and internal convexity in such sidewalls (e.g., forming a peanut-shaped stent). Major-axis walls of an oval stent as described herein may be considered wall portions of a stent that are intersected by a major axis of the stent that runs through an axial center of the stent. Minor-axis walls of such oval stents may be considered wall portions that are intersected by a minor axis of the stent that runs through the axial center of the stent. The description below of the various examples of stents having non-circular cross-sectional portions / sections provide further context for interpreting the terms “oval,” “peanut,” and “non-circular” in the context of oval stents and stents having oval portions / segments. Example stents of the present disclosure may be considered to have an oval shape whether or not the shape thereof is definable by an algebraic curve. Example stents of the present disclosure may be considered oval stents when the wall(s) of the stent in an axial-cross- sectional perspective form(s) a closed curve in a plane Ps that is non-circular; one or more segments / areas thereof may resemble the outline of a portion of an egg. Oval stents of the present disclosure may include either one or two axes of symmetry of an ellipse, such as the illustrated major Amaj and minor Amin axes. The axial cross-section of some examples of oval stents of the present disclosure may resemble the union of two semicircles on opposite sides of a rectangle, providing a shape evoking the likeness of a speed skating rink or an athletics track. In some contexts, the oval stent 600 may be referred to as a “stadium”-shaped stent, or an elongated oval.

[0085] The stent frame 631 comprises stent wall(s) defining an elongated tubular structure having a first axial end 621a with a first opening 622a. The tubular structure may further comprise a second axial end 621b with a second opening 622b, wherein the lumen / channel 649 extends between the first opening 622a and the second opening 622b, traversing the length L of the stent 600. The frame 631 and / or wall(s) thereof may comprise an open-cell structure adapted to be expanded to secure the stent 600 to a blood vesselDocket No.: ADV-23439WO01 internal (or external) wall, such as through a pressure-fit deployment, one or more tissue anchors / barbs, and / or endothelialization of the frame 631 to the vessel tissue over time.

[0086] The stent 600 may be elastically deformable between a first, non-circular configuration and a second, more-circular configuration (see dashed-line representation in Figure 7), with the stent 600 biased toward the first configuration. In some examples, the stent frame 631 may comprise a shape-memory material, such as Nitinol. Although shown as an oval-shaped stent, the stent 600 may be any non-circular shape in a resting state thereof, such as a triangle, peanut, figure-8, and / or kidney shape.

[0087] The stent 600 may be configured to be percutaneously delivered to a blood vessel in a compressed delivery configuration. Once within the blood vessel lumen at the target deployment site, the stent 600 and / or frame 631 thereof may be configured to be radially expanded into direct surface contact with the blood vessel wall (e.g., the inner wall of an aorta segment). In some examples, the stent 600 may be configured to be expanded such that the perimeter of the stent 600 approximates and / or exceeds a perimeter of the blood vessel portion where the stent 600 is implanted, at least immediately prior to deployment / expansion of the stent. In some cases, a stent configured to expand to a greater perimeter than the native blood vessel may provide improved traction and / or resistance to migration within the blood vessel. Moreover, where the stent has a perimeter approximate to and / or slightly greater than the blood vessel perimeter may increase and / or ensure positive engagement with the blood vessel and / or maximize a compliance effect. The stent wall and / or a portion of the stent wall may be configured to be endothelialized to the blood vessel wall.

[0088] In the oval configuration shown in Figures 6A–6D, the stent 600 may have a cross-sectional area having a major / long axis diameter dmajthat is substantially larger than the minor / short axis diameter dmin. For example, the major-axis diameter / dimension dmaj may advantageously be at least twice as long as the minor-axis diameter / dimension dmin, or even 3, 4, 5, 6, or 7 times greater. The stent 600 may be configured to increase compliance of a blood vessel though constant or near-constant pressure at one or more points along a perimeter / circumference of the blood vessel to cause a change in the perimeter geometry of the vessel. For example, the blood vessel may be changed and / or moved from a non- circular / less-circular shape to a circular / more-circular shape.

[0089] The stent frame wall(s) 631 may be at least partially composed of struts 638 and / or stent openings / cells 635 between the struts 638. The dimensions and / or shape of the stent 600 may vary based on the particular application and / or target implantation anatomy. For example, the stent length L may be selected to extend over all or a portion of anDocket No.: ADV-23439WO01 identified non-compliant length of a target blood vessel. The stent major axis dmajand minor axis dmin, when averaged, may be approximately equal to the diameter of the native blood vessel. For example, for a stent configured for deployment in an aorta, the length L may be between 1–45 cm, and in the biased oval / diastolic configuration the major axis dmajmay be between 1–4 cm (or larger / smaller depending on the particular anatomy), and the minor axis dmincan be between 20–50 percent of the major axis dmaj. However, other sizes and / or shapes are also within the scope of this disclosure.

[0090] Figure 7 shows an axial view of the uncovered, non-circular stent 600 shown in Figures 6A–6D deployed within a blood vessel 61 in accordance with one or more examples. The stent 600 may be biased toward the illustrated oval and / or other non-circular relaxed / diastolic configuration (shown in solid-line), and may, when subjected to mechanical forces associated with high luminal pressure, be configured to responsively transform to a more circular systolic configuration (shown in dashed-line) such that the minor axis dmin approaches, and may equal, the major axis dmaj. The cells 635 of the frame 631, formed by the arrangement of the struts 638, provide openings in the frame 631 that allow blood in the blood vessel in which the stent 600 is deployed to transfer pressure through the frame 631, to thereby load the inner diameter / surface of the blood vessel with a force resulting from increases in the luminal blood pressure as the heart beats.

[0091] Luminal pressure forces against the blood vessel wall increase the hoop stress on the blood vessel, which may force the blood vessel, and with it the stent 600, to assume a more-circular shape. The resulting hoop stress, also referred to as “tangential stress” or “circumferential stress,” from luminal pressure increase exerts radially-outward force along the blood vessel’s inner circumference, such stresses / forces being tensile in nature, which can tend to cause the blood vessel to increase in diameter. However, where the elasticity of the blood vessel wall is compromised, as with the blood vessel 61, the expansion of the blood vessel diameter is limited, and therefore, the pressure increase reshapes the blood vessel without substantially increasing the circumference thereof. The blood pressure force on the blood vessel wall and resulting inward deflection of the blood vessel walls (due to outward deflection of the vessel wall portions in the area of the minor axis Amin) at the major-axis-ends 627 of the stent 600 may cause inward deflection of the ends 627 of the stent 600 to form a desired geometric change to a more-circular shape of the blood vessel and stent 600.

[0092] The transition of the stent from oval to the more-circular stent shape 600’ (shown in dashed-line in Figure 7) causes energy to be stored in the stent frame 631 (e.g., inDocket No.: ADV-23439WO01 the elasticity and / or shape memory thereof), such that energy is returned to the blood vessel walls 62, and therefore to the blood circulation within the blood vessel segment, when the frame transitions back to the oval shape as pressure decreases. The shape memory forces of the stent 600 are advantageously sufficient to overcome the pressure forces within the blood vessel 61 to return the stent 600 to the oval configuration 600 in the presence of diastolic pressure conditions, thereby reshaping the blood vessel 61 to a non-circular (e.g., generally- oval) cross-sectional shape. With respect to implantation within the aorta or other arterial blood vessel, the systolic phase of the cardiac cycle, during which pressure levels in the aorta / arteries are relatively higher, causes the expansion of the blood vessel 61 and stent 600 to the more-circular shape (shown in dashed-line in Figure 7), whereas the diastolic phase, which is associated with relatively lower arterial blood pressure levels, causes the elongation of the stent in the major axis Amajdimension to the lower-energy oval configuration, thereby forcing the blood vessel 61 to likewise assume a more oval shape due to the blood vessel having a perimeter / circumference that is sufficiently close to the perimeter / circumference length of the stent 600 (e.g., within 20% of the length of the perimeter / circumference of the stent 600).

[0093] The natural cross-sectional shape of the aorta (and other blood vessels) may generally be circular; as explained above, for a given blood vessel wall circumference / perimeter length, the circular configuration of the blood vessel may provide the maximum area / volume within the respective blood vessel segment. Therefore, any deviation from such circular / cylindrical form of the blood vessel wall may decrease the area / volume within the respective blood vessel segment. With the oval stent 600 pushing outward to the oval configuration, the wall portions 63 may be pulled / drawn at least partially towards an axial center Av of the blood vessel 61 and / or towards each other in a manner as to cause the blood vessel 61 to form a non-circular / -cylindrical shape, such as an oval shape as shown in Figure 7. That is, compared to the circular / cylindrical shape of the blood vessel 61, the blood vessel 61 in the oval shape has a cross-sectional area in the axial segment / area where the stent 600 is implanted that is reduced.

[0094] Due to the circumference / perimeter of the blood vessel 61 being similar to the circumference / perimeter of the stent frame 631, the configuration of the stent 600 in the oval shape causes the aortic wall 61 to assume a more oval shape to match the stent 600. However, depending on the relative size of the stent 600 to the vessel 61, the blood vessel 61 may not necessarily conform exactly to the circumference and / or shape of the oval stent 600, and some minor gap(s) 68 may be present and / or form between the frame 631 and the bloodDocket No.: ADV-23439WO01 vessel wall 63 as the luminal pressure increases and pushes the vessel side walls 63 away from the frame sidewall 625.

[0095] As the stent 600 comprises a bare-frame (e.g., bare-metal) stent, wherein the frame 631 is not covered internally or externally by a fluid-tight covering, the origin of the driving force required to transition the frame 631 from the oval shape to the more circular shape 600’ may necessarily be based on hoop pressure / stress against the vessel inner diameter. Coverings and other components of example implant devices of the present disclosure can comprise any type of biocompatible material, such as, but not limited to, expanded polytetrafluoroethylene (ePTFE), polyester, polyurethane, fluoropolymers (e.g., perfluoroelastomers and the like), polytetrafluoroethylene, polyethylene terephthalate (Dacron), silicones, urethanes, ultra-high molecular weight polyethylene, aramid fibers, and combinations thereof.

[0096] The luminal pressure exerts radial outward force against the vessel internal wall, wherein such forces indirectly act against the major axis dmaj of the stent 600 to force outward deflection of the sidewalls 625 towards the circular 600’. For example, as theblood pressure increases in the vessel 61, the hoop stress on the blood vessel walls may force the side wall portions 63 of the blood vessel 61 to deflected radially outward towards a more uniform circular shape of the blood vessel 61, wherein the stiffness of the blood vessel wall causes the outward deflection of the sidewalls 63 to pull radially inward on the end walls 62 of the blood vessel, thereby applying radially-inward pressure on the end walls 627 of the stent frame 631. Such pressures force inward deflection of the walls 627 of the stent 600, thereby allowing the sidewalls 63 of the blood vessel 61 to deflect outwardly towards the circle dimension as pushed by the stent sidewalls 625. The walls 63 may be forced outward by outward radial deflection of the sidewalls 625 of the stent resulting from the translation / transfer of mechanical force from the end walls 627 to the side walls 625 causing a radially-outward moment / force in the side walls 625. The force vector pushing radially inwardly on the side wall 627 creates peripheral tension / stress (e.g., ring / hoop stress) in the sidewalls 625, which causes the outward deflection thereof. Therefore, with a bare-frame stent, transition force for transitioning the stent to a circular shape from an oval shape may necessarily be implemented from two primary contact points in the areas of the sidewalls 627 and / or vertices Ve associated with the major-access ends of the stent frame 631. Such forces inwardly compress the major axis dmajof the stent 600. The force vectors pushing against the ends 627 of the frame 631 maybe required to be sufficient to overcome the concentrated resistance at the sides 627 and / or vertices Veof the frame 631. In view of theDocket No.: ADV-23439WO01 elongated shape of the oval frame 631, the radially outward resistive force of the frame 631 may be greater at the major-axis ends 627 than at the minor axis walls 625, such that a relatively substantial force may be required to cause the inward deflection of the frame ends 627.

[0097] As the pressure in the blood vessel 61 increases (e.g., in connection with the systolic phase of the cardiac cycle), the plastically deformable nature of the stent 600 allows for the sidewalls 625 of the frame 631 to be pushed outward to accommodate the shortening of the stent 600 in the major axis dimension Amaj. When the ends 627 of the stent 600 are brought closer together (as pushed radially inward by the blood vessel walls 62), the stent 600 allows / compels the blood vessel 61 to assume a more circular cross-sectional shape. That is, the stent 600 improves cardiac perfusion by causing a decrease in cross-sectional blood vessel area during diastole relative to systole due to the reshaping of the blood vessel 61 caused by the lengthening of the major diameter dmaj of the stent 600. For example, for an insufficiently compliant blood vessel, the outer wall / perimeter of the blood vessel may generally not change sufficiently between systole in diastole due to a lack of stretching of the blood vessel wall. Therefore, with a typical circular cross-sectional shape throughout the cardiac cycle, the cross-sectional area of the blood vessel may not change sufficiently between cardiac phases, resulting in poor perfusion. Examples of the present disclosure solve this problem by leveraging the principle that a non-circular cross-sectional shape will have lesser area than a circular cross-sectional shape having the same perimeter length. In particular, implant devices presented herein are configured to achieve improved perfusion by changing the cross-sectional area of the aorta (or other blood vessel) from a more-circular to a less-circular (e.g., oval) shape as the cardiac cycle transitions from systole to diastole. The compliance-enhancing stent 600 is expanded in the minor-axis dimension dmin in response to higher-pressure conditions to allow the vessel 61 to assume a more circular shape, after which the shape memory bias in the stent 600 pushes the vessel walls 62 back outward as pressure drops, thereby pushing blood through the vessel and improving perfusion.

[0098] The stent frame 631 may be inclined to experience tissue in-growth in one or more areas thereof. For example, the end walls 627 may be relatively stationary relative to the blood vessel walls 62 throughout the cardiac cycle due to the relatively constant contact between the stent side walls 627 and the blood vessel sidewalls 62 between oval and circular shapes of the stent 600. Conversely, the sidewalls 625 of the frame 631 and the sidewalls 63 of the blood vessel may tend to come into contact with one another and separate in a cyclical manner as the blood pressure forces the blood vessel sidewalls 63 outward and away from theDocket No.: ADV-23439WO01 stent sidewalls 625 during portion(s) of the high-pressure phase / stage of the cardiac cycle. Therefore, tissue ingrowth may occur primarily between the blood vessel sidewalls 62 and the stent sidewalls 627 in situations in which tissue ingrowth occurs. That is, due to the hoop stresses on the blood vessel 61 causing cyclic detachment preventing tissue ingrowth with respect to the longer and / or straighter sidewalls of the stent and blood vessel, tissue ingrowth can grow more in the major-axis regions where contact between stent and blood vessel is relatively more continuous / constant throughout cardiac cycling.

[0099] As with any of the examples disclosed herein, the stent 600 can be configured to deflect from the oval shape to a more-circular shape in the presence of threshold blood pressure levels greater than 80 mmHg, such as blood pressure levels greater than 90 mmHg (e.g., between 90–120 mmHg).

[0100] Figures 8A and 8B show perspective and axial views, respectively, of a non-circular stent 200 having inwardly deflected sidewalls 225 in accordance with one or more examples. The stent 200 may represent an example implementation of any of the non- circular / oval stents disclosed herein, or portion(s) thereof. The stent 200 forms / defines an elongate / elongated tubular member, as shown in Figure 8A, which forms a blood flow lumen 249.

[0101] The shape of the stent 200 deviates from the stent shown in Figures 6A– 6D only in that the major-axis (e.g., relatively flat and / or long) sidewalls 225 deflect to a greater degree towards the center / axis As of the stent 200 in a relaxed state. The resulting shape may resemble that of an hourglass and / or peanut shape with respect to the axial cross- section shown in Figure 8B. The stent 200 may have a major axis diameter / dimension dmaj that is greater than a minor axis diameter / dimension dmin of the oval cross-section. As with other oval stents disclosed herein, the stent 200 is configured to change in perimeter geometry to transition from the illustrated non-circular shape to a more-circular configuration in response to the application of certain mechanical forces on one or more points / portions thereof.

[0102] In some examples, the stent 200 may be biased to a shape having a minor axis dimension dmin that is non-constant along the major axis Amaj dimension, which forms an externally-concave / internally-convex surface / form with respect to the minor axis sidewalls 225. For example, the minor axis sidewalls 225 may have a diameter dimension dmin1 at a center thereof (with respect to the major axis dimension Amaj) that is less than the diameter / dimension dmin2 at / towards the end portions of the minor-axis sidewalls 225. Non- circular stents of the present disclosure that have externally-concave / internally-convexDocket No.: ADV-23439WO01 minor-axis sidewalls as shown in Figure 8A and 8B are referred to herein as peanut-shaped stents; such peanut shape can be considered a variation of an oval, or oval-shaped, stent as described herein. The inwardly bent walls 225 can allow for a transition reshaping between peanut-shaped, to outwardly bowed oval shape, and ultimately to circular / more-circular shape.

[0103] The stent 200, though configured to transition to a more-circular configuration when certain forces are applied thereto, may be biased toward the illustrated non-circular, peanut diastolic shape. The stent 200 that may be biased (such as being memory-set via a memory material such as Nitinol) toward the peanut shape. With the sidewalls 225 deflected inwardly, as shown, the stent frame 200 may form bulging / bulbous portions 269a, 269b on either side of the minor axis Amin, wherein such portions have a diameter / dimension dmin2that is greater than the shortened diameter dmin1. The resulting shape of a blood vessel in which the stent 200 is deployed when the stent 200 is in the relaxed peanut configuration can reduce a diameter / dimension of the blood vessel parallel with the minor axis Amin in the area of the minor axis. The dimension / diameter of the blood vessel in the major axis dimension Amaj may become elongated when the wall portions 225 are brought closer together to form the peanut shape.

[0104] When deployed in a blood vessel, oval stents that are configured to transition between oval and more-circular shape / configurations may experience some degree of transition towards a more-circular shape in response to even minimum pressure conditions within the blood vessel, such as may be associated with the diastolic phase of the cardiac cycle with respect to arterial stent deployments. Therefore, between the low-and high- pressure phases of the cardiac cycle, the change in cross-sectional area of the stent may be reduced to some degree by the premature transition to a more-circular shape due to the minimum luminal blood pressure in the target vessel. The inward deflection of the stent walls 225 to produce concavity thereof in the peanut shape in the relaxed configuration of the stent 200 can bias the shape of the stent in a manner such that slight outward deflection of the walls 225 caused by minimum pressure conditions in the target blood vessel serves to flatten- out the walls 225 without deflecting- / bowing-out the walls 225 to a substantial degree rather than producing a more-circular configuration thereof. Therefore, the desired change in area / volume of the stent between low-and high-pressure phases is preserved / maintained. Therefore, the peanut configuration of the sidewalls 225 can compensate for premature rounding-out / transformation of the stent into more-circular shapes.Docket No.: ADV-23439WO01

[0105] The stent 200 may be biased toward the illustrated peanut relaxed / diastolic configuration. When subjected to radially expansive forces, the stent is configured to responsively transform to a more circular systolic configuration such that the minor axis dminapproaches, and may equal, the major axis dmaj. The cells 235 of the frame 231, formed by the arrangement of the struts 238, provide openings in the frame 231 that allow bloodblood vessel in which the stent 200 isto transfer pressure through the frame 231, to thereby load the inner diameter / surface of the blood vessel with a force resulting from increases in the luminal blood pressure as the heart beats.

[0106] The blood pressure force against the blood vessel walls increases the hoop stress on the blood vessel, which may force the blood vessel, and with it the stent 200, to assume a more-circular shape. When the elasticity of the blood vessel wall is compromised, the expansion of the blood vessel diameter is limited, and therefore, the pressure increase reshapes the blood vessel without substantially increasing the circumference thereof. The blood pressure force on the blood vessel wall and resulting inward deflection of the blood vessel walls at the major-axis-ends 227 of the stent 200 may cause inward deflection of the ends 227 of the stent 200 to form a desired geometric change to a more-circular shape of the stent 200, and with it the blood vessel 61.

[0107] The transition of the stent from oval to the more-circular stent shape causes energy to be stored in the stent frame 231 (e.g., in the elasticity and / or shape memory thereof), such that energy is returned to the blood vessel walls, and therefore to the blood circulation within the blood vessel segment, when the frame transitions back to the oval shape as pressure decreases. The shape memory forces of the stent 200 are advantageously sufficient to overcome the pressure forces within the blood vessel 61 to return the stent 200 to the oval configuration in the presence of diastolic pressure conditions, thereby reshaping the blood vessel to a non-circular (e.g., generally-oval) cross-sectional shape. With respect to implantation within the aorta or other arterial blood vessel, the systolic phase of the cardiac cycle, during which pressure levels in the aorta / arteries are relatively higher, causes the expansion of the blood vessel and stent 200 to the more-circular shape, whereas the diastolic phase, which is associated with relatively lower arterial blood pressure levels, causes the elongation of the stent in the major axis Amajdimension to the lower-energy oval configuration, thereby forcing the blood vessel to likewise assume a more oval shape due to the blood vessel having a perimeter / circumference that is sufficiently close to the perimeter / circumference length of the stent 200 (e.g., within 20% of the length of the perimeter / circumference of the stent 200). As with any stent device disclosed herein, the stentDocket No.: ADV-23439WO01 200 can be implanted within the venous system, such as within the inferior vena cava or superior vena cava.

[0108] The natural cross-sectional shape of the aorta (and other blood vessels) may generally be circular; as explained above, for a given blood vessel wall circumference / perimeter length, the circular configuration of the blood vessel may provide the maximum area / volume within the respective blood vessel segment. Therefore, any deviation from such circular / cylindrical form of the blood vessel wall may decrease the area / volume within the respective blood vessel segment. With the oval stent 200 pushing outward to the oval configuration, the wall portions may be pulled / drawn at least partially towards an axial center Avof the blood vessel and / or towards each other in a manner as to cause the blood vessel to form a non-circular / -cylindrical shape, such as the peanut shape. That is, compared to the circular / cylindrical shape of the blood vessel 61, the blood vessel in the oval shape has a cross-sectional area in the axial segment / area where the stent 200 is implanted that is reduced.

[0109] Due to the circumference / perimeter of the blood vessel being similar to the circumference / perimeter of the stent frame 231, the configuration of the stent 200 in the oval shape causes the or aortic wall to assume a more oval or peanut shape to match the stent 200. However, depending on the relative size of the stent 200 to the vessel, the blood vessel may not necessarily conform exactly to the circumference and / or shape of the oval stent 200, and some minor gap between the stent walls 225 and the vessel walls may be present and / or form as the luminal pressure increases and pushes the vessel side walls away from the frame sidewalls 225.

[0110] As the stent 200 comprises a bare-frame stent, wherein the frame 231 is not covered by a fluid-tight covering, the origin of the driving force required to transition the frame 231 from the oval shape to the more circular shape may necessarily be based on hoop pressure / stress against the vessel inner diameter, wherein the luminal pressure exerts radial outward force against the vessel internal wall, such forces indirectly acting against the major axis dmaj of the stent 200 to force outward deflection of the sidewalls 225 towards the circular shape. For example, as the blood pressure increases in the vessel, the hoop stress on the blood vessel walls may force the side wall portions of the blood vessel to deflected radially outward towards a more uniform circular shape of the blood vessel, wherein the stiffness of the blood vessel wall causes the outward deflection of the sidewalls to pull radially inwardly on the end walls of the blood vessel, thereby applying radially-inward pressure on the end walls 227 of the stent frame 231. Such pressures force inward deflection of the walls 227 of the stent 200,Docket No.: ADV-23439WO01 thereby allowing the sidewalls of the blood vessel 61 to deflect outwardly towards the circle dimension.

[0111] The translation of force from the end wall 227 to the side wall 225 can cause a radially outward moment / force in the side wall 225. For example, the force vector pushing radially inwardly on the side walls 227 can create peripheral tension / stress (e.g., ring / hoop stress) in the sidewalls 225 due to the mechanical continuity / coupling between the end walls 227 and the sidewalls 225, which can cause the outward deflection of the sidewalls 225. Therefore, with a bare-frame peanut stent, transition force for transitioning the stent to a more-circular shape from a peanut shape may necessarily be implemented from two primary contact points in the area of the sidewalls 227 and / or vertices veassociated with the major- access ends of the stent frame 231. Such forces inwardly compress the major axis dmaj of the stent 200. The force vectors pushing against the ends 227 of the frame 231 may necessarily be required to be sufficient to overcome the concentrated resistance at the sides 227 and / or vertices Ve of the frame 231. In view of the elongated shape of the peanut frame 231, the radially outward resistive force of the frame 231 may be greater at the major access ends 227 than at the minor axis walls 225, such that a relatively substantial force may be required to cause the inward deflection of the frame ends 227.

[0112] As the pressure in the blood vessel increases (e.g., in connection with the systolic phase of the cardiac cycle), the plastically deformable nature of the stent 200 allows for the sidewalls 225 of the frame 231 to be pushed outward to accommodate the shortening of the stent 200 in the major axis dimension Amaj. When the ends 227 of the stent 200 are brought closer together (as pushed radiallyby the blood vessel walls 22, the stent 200 allows the blood vessel 61 to assume a more circular cross-sectional shape. That is, the stent 200 improves cardiac perfusion by causing a decrease in cross-sectional blood vessel area during diastole relative to systole due to the reshaping of the blood vessel caused by the lengthening of the major diameter dmaj of the stent 200.

[0113] Figure 9 illustrates an example implant system for modifying pulmonary waves in accordance with one or more examples. In Figure 9, the main pulmonary artery (PA) 18 branches into the right pulmonary artery (RPA) 13 and the left pulmonary artery (LPA) 11. Forward waves flow away from the pulmonary valve (not shown), and backward waves flow toward the pulmonary valve. In the example of Figure 9, forward waves in the PA 18 flow toward the RPA 13 and the LPA 11. Backward waves in the RPA 13 flow toward the PA 18, and backward waves in the LPA 11 flow toward the PA 18. The backward waves may converge where the RPA 13 and the LPA 11 meet.Docket No.: ADV-23439WO01

[0114] The implant system may involve placement of one or more stents 902 within the PA 18, RPA 13, LPA 11, and / or other blood vessels. For example, a first stent 902a may be placed in the PA 18, a second stent 902b may be placed in the RPA 13, and / or a third stent 902c may be placed in the LPA 11. In some examples, the first stent 902a, second stent 902b, and / or third stent 902c may have oval and / or peanut shapes. While the stents 902 are shown in Figure 9 having peanut shapes, stents 902 may have other shapes as described herein.

[0115] In some examples, the stents 902 may be oriented at different circumferential and / or axial orientations relative to each other. For example, ends of the major axes of the stents 902 may be configured to contact sides of the various blood vessels. However, the sides of the blood vessels in contact with the ends of the major axes may change depending on a circumferential and / or axial rotation of the stent 902. Thus, the various stents 902 may be rotated to varying degrees to form different axial rotations. As a result, the blood vessels may have different major and / or minor axes. In this way, the stents 902 may be configured to cause dampening of waves (e.g., pulmonary waves) and / or shortening of systolic durations of such waves. The stents 902 may be configured to prevent generation of backflow waves by stiffened pulmonary vasculature during systole which can decrease cardiac output and / or increase intra-cardiac pressure.

[0116] Each stent 902 may be individually configured to increase compliance in stiffened vasculature. In the case of a stiffened pulmonary vasculature, one or more stents 902 can be used to increase the compliance of the pulmonary blood vessel (e.g., PA 18).

[0117] While three stents 902 are shown in Figure 9, other numbers of stents 902 may be used. For example, only the first stent 902a in the PA 18 and / or the second stent 902b in the RPA 13 may be employed. Alternatively, only the first stent 902a in the PA 18 and / or the third stent 902c in the LPA 11 may be employed. In another example, only the second stent 902b in the RPA 13 and / or the third stent 902c in the LPA 11 may be employed.

[0118] In some examples, the stents 902 may be configured to increase vascular compliance and / or attenuation of reflected waves to some degree. Moreover, the stents 902 may be configured to shorten the occurrence of waves during systole.

[0119] As shown in Figure 9, the second stent 902b and / or third stent 902c may have different orientations relative to the first stent 902a. For example, the second stent 902b and / or third stent 902c may be positioned generally perpendicularly to the first stent 902a. The second stent 902b and / or third stent 902c may have a common and / or identical orientation relative to each other. For example, the PA 18, RPA 13, and / or LPA 11 mayDocket No.: ADV-23439WO01 extend along a common plane. The major axis of the first stent 902a may be approximately parallel to the common plane and / or the major axes of the second stent 902b and / or third stent 902c may be approximately orthogonal and / or perpendicular to the common plane. In some examples, branching blood vessels may not extend along a common plane to trunk vessel. In such cases, the second stent 902b and / or third stent 902c may be rotated approximately 90- degrees axially to the direction of blood flow relative to the first stent 902a.

[0120] The first stent 902a may be oriented about a central axis 911 of the PA 18. For example, a central point of a lumen of the first stent 902a may be approximately aligned with the central axis 911. The PA 18 may form a generally circular shape about the central axis 911 and / or may form an oval and / or peanut shape in response to placement of the first stent 902a. A major axis of the first stent 902a may extend laterally from the central axis 911 along a first lateral plane 913 and / or a minor axis of the first stent 902a may extend laterally from the central axis 911 along a second lateral plane 915. The second lateral plane 915 may be approximately perpendicular to the first lateral plane 913 and / or may form an approximately 90-degree angle with the first lateral plane 913.

[0121] The second stent 902b and / or third stent 902c may be rotationally offset from the first stent 902a. For example, major axes of the second stent 902b and / or the third stent 902c may extend along the second lateral plane 915 and / or minor axes of the second stent 902b and / or third stent 902c may extend along the first lateral plane 913. The central axis 911, first lateral plane 913, and / or second lateral plane 915 may be relative to each blood vessel. For example, as shown in Figure 9, the RPA 13 may branch from the PA 18 and / or may extend at an approximately 45-degree angle from the PA 18. Accordingly, the central axis 911 of the RPA 13 may be offset by 45-degrees and / or other angle from the PA 18. The first plane 913 and / or the second plane 915 may be consistent in multiple blood vessels and / or may adjust based on the orientations of the blood vessels.

[0122] The different orientations of the stents 902 relative to each other can result in "wave-rolling," which can optionally further dampen and shorten reflected waves.

[0123] While the stents 902 are shown as separate devices for exemplary purposes, the stents 902 may be interconnected and / or may extend into each other. In some examples, the implant system may comprise a covering extending over and / or along the stents 902 and / or interconnecting the stents 902.

[0124] Figure 10 illustrates another example implant system for modifying pulmonary waves in accordance with one or more examples.Docket No.: ADV-23439WO01

[0125] The implant system may involve placement of one or more stents 1002 within the PA 18, RPA 13, LPA 11, and / or other blood vessels. For example, a first stent 1002a may be placed in the PA 18, a second stent 1002b may be placed in the RPA 13, and / or a third stent 1002c may be placed in the LPA 11. In some examples, the first stent 1002a, second stent 1002b, and / or third stent 1002c may have oval and / or peanut shapes. While the stents 1002 are shown in Figure 10 having peanut shapes, stents 1002 may have other shapes as described herein.

[0126] In some examples, the stents may be oriented at different circumferential and / or axial orientations relative to each other. For example, ends of the major axes of the stents 1002 may be configured to contact sides of the various blood vessels. However, the sides of the blood vessels in contact with the ends of the major axes may change depending on a circumferential and / or axial rotation of the stent 1002. Thus, the various stents 1002 may be rotated to varying degrees to form different axial rotations. In this way, dampening of waves (e.g., pulmonary waves) and / or shortening of systolic durations of such waves. The stents 1002 may be configured to prevent generation of backflow waves by stiffened pulmonary vasculature during systole which can decrease cardiac output and / or increase intra-cardiac pressure.

[0127] Each stent 1002 may be individually configured to increase compliance in stiffened vasculature. In the case of a stiffened pulmonary vasculature, one or more stents 1002 can be used to increase the compliance of the pulmonary blood vessel (e.g., PA 18).

[0128] While three stents 1002 are shown in Figure 10, other numbers of stents 1002 may be used. For example, only the first stent 1002a in the PA 18 and / or the second stent 1002b in the RPA 13 may be employed. Alternatively, only the first stent 1002a in the PA 18 and / or the third stent 1002c in the LPA 11 may be employed. In another example, only the second stent 1002b in the RPA 13 and / or the third stent 1002c in the LPA 11 may be employed.

[0129] In some examples, the stents 1002 may be configured to increase vascular compliance and / or attenuation of reflected waves to some degree. Moreover, the stents 1002 may be configured to shorten the occurrence of waves during systole.

[0130] As shown in Figure 10, the second stent 1002b and / or third stent 1002c may have different orientations relative to the first stent 1002a. For example, the second stent 1002b and / or third stent 1002c may be positioned at oblique angles relative to the first stent 1002a. The second stent 1002b and / or third stent 1002c may have a common and / or different orientation relative to each other. For example, the second stent 1002b may be rotatedDocket No.: ADV-23439WO01 approximately 45-degrees in a first rotational direction relative to the first stent 1002a and / or the third stent 1002c may be rotated approximately 45-degrees in a second rotational direction (i.e., 315-degrees in the first direction) relative to the first stent 1002a.

[0131] The first stent 1002a may be oriented about a central axis 1011 of the PA 18. For example, a central point of a lumen of the first stent 1002a may be approximately aligned with the central axis 1011. The PA 18 may form a generally circular shape about the central axis 1011 and / or may form an oval and / or peanut shape in response to placement of the first stent 1002a. A major axis of the first stent 1002a may extend laterally from the central axis 1011 along a first lateral plane 1013 and / or a minor axis of the first stent 1002a may extend laterally from the central axis 1011 along a second lateral plane 1015. The second lateral plane 1015 may form an approximately 45-degree angle with the first lateral plane 1013 in a first direction and / or a third lateral plane 1017 may form an approximately 45- degree angle with the first lateral plane 1013 in a second direction.

[0132] The second stent 1002b and / or third stent 1002c may be rotationally offset from the first stent 1002a. For example, major axes of the second stent 1002b and / or the third stent 1002c may extend along the second lateral plane 1015 and / or minor axes of the second stent 1002b and / or third stent 1002c may extend along the third lateral plane 1017. The central axis 1011, first lateral plane 1013, second lateral plane 1015, and / or third lateral plane 1017 may be relative to each blood vessel. For example, as shown in Figure 10, the RPA 13 may branch from the PA 18 and / or may extend at an approximately 45-degree angle from the PA 18. Accordingly, the central axis 1011 of the RPA 13 may be offset by 45-degrees and / or other angle from the PA 18. The first plane 1013 and / or the second plane 1015 may be consistent in multiple blood vessels and / or may adjust based on the orientations of the blood vessels.

[0133] Figures 11A and 11B illustrate an example oval-shaped stent 1100 for modifying pulmonary waves in accordance with one or more examples. Figure 11A provides a perspective view of the stent 1100 and Figure 11B provides a top (e.g., overhead) view of the stent 1100. The stent 1100 may comprise a frame and / or wireform forming struts 1121 and / or cells 1123 between the struts 1121. While the struts 1121 are shown forming diamond- shaped cells 1123, the struts 1121 and / or cells 1123 may have other configurations and / or shapes. Moreover, while the stent 1100 is shown having an oval shape, the stent 1100 may have other shapes as described herein.

[0134] In some examples, the stent 1100 may have a varying form along a length of the stent 1100. For example, the stent 1100 may comprise a first portion 1112, a secondDocket No.: ADV-23439WO01 portion 1114, and / or a third portion 1116. The configurations and / or patterns of struts 1121 and / or cells 1123 may be different in different portions of the stent 1100. For example, the stent 1100 may comprise relatively small cells 1123 and / or compact struts 1121 at the first portion 1112, relatively average and / or medium cells 1123 and / or relatively evenly spaced struts 1121 at the second portion 1114, and / or relatively large cells 1123 and / or expanded struts 1121 at the third portion 1116.

[0135] The first portion 1112, second portion 1114, and third portion 1116 may be aligned in series along the length of the stent 1100. For example, the stent 1100 may be positioned such that the first portion 1112 is situated towards a direction of blood flow and / or such that blood flow first passes through the first portion 1112 before passing through the second portion 1114 and / or third portion 1116. The second portion 1114 may be disposed between the first portion 1112 and the third portion 1116.

[0136] In some examples, the first portion 1112, second portion 1114, and third portion 1116 may comprise a continuous and / or common network of struts 1121. For example, struts 1121 of the first portion 1112 may extend into the second portion 1114 and / or struts 1121 of the second portion 1114 may extend into the first portion 1112 and / or third portion 1116. The struts 1121 may be shape-set to have a more expanded and / or spaced form in the second portion 1114 and third portion 1116 relative to the first portion 1112. Additionally, or alternatively, the first portion 1112, second portion 1114, and third portion 1116 may comprise at least partially different struts 1121 and / or networks of struts 1121. For example, the first portion 1112 may comprise more struts 1121 than the second portion 1114 and / or third portion 1116. Similarly, the second portion 1114 may comprise more struts 1121 than the third portion 1116. At least a portion of the struts 1121 of the first portion 1112 may extend into the second portion 1114 and / or at least a portion of the struts 1121 of the second portion 1114 may extend into the first portion 1112 and / or third portion 1116.

[0137] Figures 12A and 12B illustrate an example peanut-shaped stent 1200 for modifying pulmonary waves in accordance with one or more examples. Figure 12A provides a cross-sectional view of the stent 1200 and Figure 12B provides a top (e.g., overhead) view of the stent 1200. The stent 1200 may comprise a frame and / or wireform forming struts 1221 and / or cells 1223 between the struts 1221. While the struts 1221 are shown forming diamond- shaped cells 1223, the struts 1221 and / or cells 1223 may have other configurations and / or shapes. Moreover, while the stent 1200 is shown having a peanut shape, the stent 1200 may have other shapes as described herein.Docket No.: ADV-23439WO01

[0138] In some examples, the stent 1200 may have a varying form along a length of the stent 1200. For example, the stent 1200 may comprise a first portion 1212, a second portion 1214, and / or a third portion 1216. The configurations and / or patterns of struts 1221 and / or cells 1223 may be different in different portions of the stent 1200. For example, the stent 1200 may comprise relatively small cells 1223 and / or compact struts 1221 at the first portion 1212, relatively average and / or medium cells 1223 and / or relatively evenly spaced struts 1221 at the second portion 1214, and / or relatively large cells 1223 and / or expanded struts 1221 at the third portion 1216.

[0139] The first portion 1212, second portion 1214, and third portion 1216 may be aligned in series along the length of the stent 1200. For example, the stent 1200 may be positioned such that the first portion 1212 is situated towards a direction of blood flow and / or such that blood flow first passes through the first portion 1212 before passing through the second portion 1214 and / or third portion 1216. The second portion 1214 may be disposed between the first portion 1212 and the third portion 1216.

[0140] In some examples, the first portion 1212, second portion 1214, and third portion 1216 may comprise a continuous and / or common network of struts 1221. For example, struts 1221 of the first portion 1212 may extend into the second portion 1214 and / or struts 1221 of the second portion 1214 may extend into the first portion 1212 and / or third portion 1216. The struts 1221 may be shape-set to have a more expanded and / or spaced form in the second portion 1214 and third portion 1216 relative to the first portion 1212. Additionally, or alternatively, the first portion 1212, second portion 1214, and third portion 1216 may comprise at least partially different struts 1221 and / or networks of struts 1221. For example, the first portion 1212 may comprise more struts 1221 than the second portion 1214 and / or third portion 1216. Similarly, the second portion 1214 may comprise more struts 1221 than the third portion 1216. At least a portion of the struts 1221 of the first portion 1212 may extend into the second portion 1214 and / or at least a portion of the struts 1221 of the second portion 1214 may extend into the first portion 1212 and / or third portion 1216.

[0141] The stent 1200 may be configured to expand from the peanut shape to a generally oval and / or circular shape in response to blood flow and / or pressure changes. The first portion 1212 is shown having the peanut shape and the third portion 1216 is shown in an expanded form having an oval and / or circular cross-sectional form. However, the first portion 1212, second portion 1214, and / or third portion 1216 may have the peanut shape as a default form and / or at initial placement within the blood vessel. The third portion 1216 is shown in an expanded form for exemplary purposes. As blood flow and / or pressure in the blood vesselDocket No.: ADV-23439WO01 changes, the third portion 1216 may be configured to more easily and / or quickly expand to the expanded form than the first portion 1212 and / or second portion 1214. For example, an amount and / or spacing of struts 1221 of the third portion 1216 may facilitate easier and / or quicker expansion of the third portion 1216 relative to the first portion 1212 and / or second portion 1214. Similarly, the second portion 1214 may more easily and / or quickly expand relative to the first portion 1212.

[0142] Figures 13A and 13B illustrate an example oval-shaped stent 1300 for modifying pulmonary waves in accordance with one or more examples. Figure 13A provides a cross-sectional view of the stent 1300 and Figure 13B provides a top (e.g., overhead) view of the stent 1300. The stent 1300 may comprise a frame and / or wireform forming struts 1321 and / or cells 1323 between the struts 1321. While the struts 1321 are shown forming diamond- shaped cells 1323, the struts 1321 and / or cells 1323 may have other configurations and / or shapes. Moreover, while the stent 1300 is shown having an oval shape, the stent 1300 may have other shapes as described herein.

[0143] In some examples, the stent 1300 may have a varying form along a length of the stent 1300. For example, the stent 1300 may comprise a first portion 1312, a second portion 1314, and / or a third portion 1316. The configurations and / or patterns of struts 1321 and / or cells 1323 may be different in different portions of the stent 1300. For example, the stent 1300 may comprise relatively small cells 1323 and / or compact struts 1321 at the first portion 1312, relatively average and / or medium cells 1323 and / or relatively evenly spaced struts 1321 at the second portion 1314, and / or relatively large cells 1323 and / or expanded struts 1321 at the third portion 1316.

[0144] The first portion 1312, second portion 1314, and third portion 1316 may be aligned in series along the length of the stent 1300. For example, the stent 1300 may be positioned such that the first portion 1312 is situated towards a direction of blood flow and / or such that blood flow first passes through the first portion 1312 before passing through the second portion 1314 and / or third portion 1316. The second portion 1314 may be disposed between the first portion 1312 and the third portion 1316.

[0145] In some examples, the first portion 1312, second portion 1314, and third portion 1316 may comprise a continuous and / or common network of struts 1321. For example, struts 1321 of the first portion 1312 may extend into the second portion 1314 and / or struts 1321 of the second portion 1314 may extend into the first portion 1312 and / or third portion 1316. The struts 1321 may be shape-set to have a more expanded and / or spaced form in the second portion 1314 and third portion 1316 relative to the first portion 1312.Docket No.: ADV-23439WO01 Additionally, or alternatively, the first portion 1312, second portion 1314, and third portion 1316 may comprise at least partially different struts 1321 and / or networks of struts 1321. For example, the first portion 1312 may comprise more struts 1321 than the second portion 1314 and / or third portion 1316. Similarly, the second portion 1314 may comprise more struts 1321 than the third portion 1316. At least a portion of the struts 1321 of the first portion 1312 may extend into the second portion 1314 and / or at least a portion of the struts 1321 of the second portion 1314 may extend into the first portion 1312 and / or third portion 1316.

[0146] The stent 1300 may have a variable diameter and / or width. For example, the stent 1300 may have a default oval and / or peanut shape comprising a major axis and / or minor axis, in which the major axis is larger than the minor axis. The major axis and / or minor axis of the stent 1300 may be greater at the second portion 1314 than at the first portion 1312 and / or greater at the third portion 1316 than at the second portion 1314.

[0147] In some examples, the stent 1300 may increase in diameter and / or width in a stepwise manner in which the width of the stent 1300 increases in steps 1325 between the first portion 1312 and the second portion 1314 and / or between the second portion 1314 and the third portion 1316. The first portion 1312, second portion 1314, and / or third portion 1316 may have generally constant diameters and / or widths at the major axes and / or minor axes.

[0148] The first portion 1312, second portion 1314, and third portion 1316 may form a series of oval and / or peanut stents. In some examples, the first portion 1312, second portion 1314, and third portion 1316 may be disconnected and / or serially arranged. The stent 1300 may comprise an integrally formed stent with a plurality of portions and / or an integrally formed stent with linear performance change. Each of the first portion 1312, second portion 1314, and third portion 1316 may have a cross-sectional area that is greater in size relative to a preceding (and / or successive) stent and / or portion.

[0149] The stent 1300 may be configured to cause phase-shifting of the reflected waves, which can shorten reflected wave duration in the systolic phase. While the stent 1300 is shown as a single device, the stent 1300 may comprise multiple detached and / or disconnected components. For example, the first portion 1312, second portion 1314, and / or third portion 1316 may each be distinct and / or separate components and / or may be serially arranged within a blood vessel and / or multiple blood vessels. The first portion 1312, second portion 1314, and / or third portion 1316 may have non-identical cross-sections that may progressively increase in size relative to one another.

[0150] The stent 1300 may have any suitable size and / or shape. In some examples, the first portion 1312, second portion 1314, and / or third portion 1316 may haveDocket No.: ADV-23439WO01 approximately equal lengths along a length of the stent 1300 extending between a first end a second end of the stent 1300. For example, each of the first portion 1312, second portion 1314, and / or third portion 1316 may have a length of approximately 7 mm, and / or the stent 1300 may have a total length of approximately 21 mm. However, the first portion 1312, second portion 1314, and / or third portion 1316 may have different lengths relative to each other.

[0151] In some examples, the stent 1300 may be arranged and / or deployed in any desired and / or suitable manner. For example, the stent 1300 may be deployed with the first portion 1312 (e.g., a thinnest portion) being nearest to a direction of blood flow. Alternatively, the stent 1300 may be deployed with the first portion 1312 being furthest from the direction of blood flow.

[0152] Buildup of reflected waves (e.g., waves reflected from the third portion 1316 and / or encountering waves formed by the second portion 1314) may both be reflected back towards (and / or encountering) waves reflected from the first portion 1312. This interaction can result in a phase shift that can shorten the duration of the reflected waves during the systolic phase. For example, blood flow passing through the third portion 1316 (e.g., a widest portion) may be slowed down due to the increase in cross-sectional area through which the blood flows. Because the cross-sectional area at the third portion 1316 is greater than at the second portion 1314, and / or because the cross-sectional area at the second portion 1314 is greater than that of the first portion 1312, the flow passing through the third portion 1316 may slow to a greater extent than the flow through the second portion 1314 and / or the flow through the second portion 1314 may decrease to a greater extent than the flow decrease through the first portion 1312. This change in flow velocities may interfere with wave propagation (e.g., similar to Ultrasound wave reflection due to change in impedance).

[0153] While the stent 1300 is shown comprising three portions, this is for exemplary purposes and any other number of portions having different cell structures, widths, and / or lengths is similarly contemplated.

[0154] The stent 1300 can comprise a progressive configuration that can be achieved by a plurality of separate oval ad / or peanut stents (e.g., portions) serially deployed one after the other. Alternatively, the stent 1300 can comprise a single stent having a plurality of axial portions, wherein each portion can have a uniform size along its length. The first portion 1312, second portion 1314, and / or third portion 1316 may have progressively increasing sizes relative to each other.Docket No.: ADV-23439WO01

[0155] Figures 14A and 14B illustrate an example oval-shaped stent 1400 for modifying pulmonary waves in accordance with one or more examples. Figure 14A provides a cross-sectional view of the stent 1400 and Figure 14B provides a top (e.g., overhead) view of the stent 1400. The stent 1400 may comprise a frame and / or wireform forming struts 1421 and / or cells 1423 between the struts 1421. While the struts 1421 are shown forming diamond- shaped cells 1423, the struts 1421 and / or cells 1423 may have other configurations and / or shapes. Moreover, while the stent 1400 is shown having an oval shape, the stent 1400 may have other shapes as described herein.

[0156] In some examples, the stent 1400 may have a varying form along a length of the stent 1400. For example, the stent 1400 may comprise a first portion 1412, a second portion 1414, and / or a third portion 1416. The configurations and / or patterns of struts 1421 and / or cells 1423 may be different in different portions of the stent 1400. For example, the stent 1400 may comprise relatively small cells 1423 and / or compact struts 1421 at the first portion 1412, relatively average and / or medium cells 1423 and / or relatively evenly spaced struts 1421 at the second portion 1414, and / or relatively large cells 1423 and / or expanded struts 1421 at the third portion 1416.

[0157] The first portion 1412, second portion 1414, and third portion 1416 may be aligned in series along the length of the stent 1400. For example, the stent 1400 may be positioned such that the first portion 1412 is situated towards a direction of blood flow and / or such that blood flow first passes through the first portion 1412 before passing through the second portion 1414 and / or third portion 1416. The second portion 1414 may be disposed between the first portion 1412 and the third portion 1416.

[0158] In some examples, the first portion 1412, second portion 1414, and third portion 1416 may comprise a continuous and / or common network of struts 1421. For example, struts 1421 of the first portion 1412 may extend into the second portion 1414 and / or struts 1421 of the second portion 1414 may extend into the first portion 1412 and / or third portion 1416. The struts 1421 may be shape-set to have a more expanded and / or spaced form in the second portion 1414 and third portion 1416 relative to the first portion 1412. Additionally, or alternatively, the first portion 1412, second portion 1414, and third portion 1416 may comprise at least partially different struts 1421 and / or networks of struts 1421. For example, the first portion 1412 may comprise more struts 1421 than the second portion 1414 and / or third portion 1416. Similarly, the second portion 1414 may comprise more struts 1421 than the third portion 1416. At least a portion of the struts 1421 of the first portion 1412 mayDocket No.: ADV-23439WO01 extend into the second portion 1414 and / or at least a portion of the struts 1421 of the second portion 1414 may extend into the first portion 1412 and / or third portion 1416.

[0159] The stent 1400 may have a variable diameter and / or width. For example, the stent 1400 may have a default oval and / or peanut shape comprising a major axis and / or minor axis, in which the major axis is larger than the minor axis. The major axis and / or minor axis of the stent 1400 may be greater at the second portion 1414 than at the first portion 1412 and / or greater at the third portion 1416 than at the second portion 1414.

[0160] In some examples, the stent 1400 may increase in diameter and / or width in a gradual manner in which the width of the stent 1400 increases gradually from a first end 1427 (e.g., of the first portion 1412) and a second end 1428 (e.g., of the third portion 1416). The first portion 1412, second portion 1414, and / or third portion 1416 may have generally variable and / or increase diameters and / or widths at the major axes and / or minor axes.

[0161] Figure 15 provides a flowchart illustrating an example process 1500 for delivering one or more stents as described in one or more examples herein. The process 1500 describes placement of three stents and / or stent portions, however other numbers of stents and / or stent portions may be used. The process 1500 describes placement of one or more implants within the PA, RPA, and / or LPA for exemplary purposes. However, the process 1500 may be applied to delivery of implants at other locations and / or blood vessels.

[0162] At a step 1502, the process 1500 involves advancing a delivery device (e.g., catheter and / or associated devices) to an RPA and / or other blood vessel via a PA and / or other blood vessel. For example, access the PA may first be achieved and the delivery device can be advanced through the PA until it reaches an RPA junction and may continue advancing into the RPA.

[0163] At a step 1504, the process 1500 involves placing a first stent and / or stent portion in the RPA. The first stent may be rotated and / or placed at a first rotational position relative to a central axis of the first stent. The first stent may have a default non-circular (e.g., oval and / or peanut) cross-sectional shape. In some examples, the first stent may comprise multiple portions and / or may have variable widths and / or cell structures along a length of the first stent.

[0164] At a step 1506, the process 1500 involves retracting the delivery device to the PA and / or other blood vessel. For example, the delivery device may retrace a delivery path to return the delivery device to the PA and / or out of the RPA.

[0165] At a step 1508, the process 1500 involves advancing the delivery device to an LPA.Docket No.: ADV-23439WO01

[0166] At a step 1510, the process 1500 involves placing a second stent and / or stent portion in the LPA. The second stent may be rotated and / or placed at a second rotational position relative to a central axis of the second stent. The second rotational position may be different relative to the first rotational position or may be approximately the same. The second stent may have a default non-circular (e.g., oval and / or peanut) cross-sectional shape. In some examples, the second stent may comprise multiple portions and / or may have variable widths and / or cell structures along a length of the first stent.

[0167] At a step 1512, the process 1500 involves retracting the delivery device back to the PA.

[0168] At a step 1514, the process 1500 involves placing a third stent and / or stent portion in the LPA. The third stent may be rotated and / or placed at a third rotational position relative to a central axis of the third stent. The third rotational position may be different relative to the first rotational position and / or second rotational position. The third stent may have a default non-circular (e.g., oval and / or peanut) cross-sectional shape. In some examples, the third stent may comprise multiple portions and / or may have variable widths and / or cell structures along a length of the first stent.

[0169] Figure 16 illustrates an example implant for modifying pulmonary waves in accordance with one or more examples. The implant may comprise two or more interconnected stents which may be configured from placement within the PA, RPA, LPA, and / or other blood vessels. For example, a first stent 1602a may be placed in the PA, a second stent 1602b may be placed in the RPA, and / or a third stent 1602c may be placed in the LPA. In some examples, the first stent 1602a, second stent 1602b, and / or third stent 1602c may have oval and / or peanut shapes. While the stents are shown in Figure 16 having peanut shapes, stents 1602 may have other shapes as described herein. The stents may be coupled together and / or may extend into each other to form a single implant. In some examples, the stents may be oriented at different circumferential and / or axial orientations relative to each other, as described in other examples herein.

[0170] While three stents are shown in Figure 16, other numbers of stents 1602 may be used. For example, the implant may comprise only the first stent 1602a (e.g., sized for placement in the PA) and / or the second stent 1602b (e.g., sized for placement in the RPA). Alternatively, the implant may comprise only the first stent 1602a and / or the third stent 1602c (e.g., sized for placement in the LPA). In another example, the implant may comprise only the second stent 1602b and / or the third stent 1602c. As shown in Figure 16, the second stent 1602b and / or third stent 1602c may have different orientations relative to theDocket No.: ADV-23439WO01 first stent 1602a. The second stent 1602b and / or third stent 1602c may be rotationally offset from the first stent 1602a.

[0171] The stents 1602 and / or portions of stents may extend at different angles relative to each other. For example, the second stent 1602b may extend at an approximately 45-degree angle relative to the first stent 1602a. In this way, the second stent 1602b may be sized and / or oriented to extend along a blood vessel (e.g., an RPA) that is at an approximately 45-degree angle relative to another blood vessel (e.g., a PA) in which the first stent 1602a may be placed in. The second stent 1602b and / or third stent 1602c may be offset approximately 45-degrees from each other and / or from the first stent 1602a. Additional Description of Examples

[0172] Provided below is a list of examples, each of which may include aspects of any of the other examples disclosed herein. Furthermore, aspects of any example described above may be implemented in any of the numbered examples provided below.

[0173] Example 1: An implant system comprising a first stent disposed in a first blood vessel, wherein the first stent has a first major axis and a first minor axis, and wherein the first major axis is larger than the first minor axis.

[0174] Example 2: The system of any example herein, in particular example 1, further comprising a second stent disposed in a second blood vessel that branches from the first blood vessel, wherein the second stent is rotationally offset relative to the first stent.

[0175] Example 3: The system of any example herein, in particular example 2, wherein the second stent has a second major axis and a second minor axis, and wherein the second major axis is larger than the second minor axis.

[0176] Example 4: The system of any example herein, in particular example 3, wherein the first major axis is rotationally offset relative to the second major axis.

[0177] Example 5: The system of any example herein, in particular example 2, further comprising a third stent disposed in a third blood vessel that branches from the first blood vessel, wherein the third stent is rotationally offset relative to the first stent.

[0178] Example 6: The system of any example herein, in particular example 5, wherein the third stent is rotationally offset relative to the second stent.

[0179] Example 7: The system of any example herein, in particular example 1, wherein the first stent has an oval shape.

[0180] Example 8: The system of any example herein, in particular example 1, wherein the first stent has a peanut shape.Docket No.: ADV-23439WO01

[0181] Example 9: The system of any example herein, in particular example 1, wherein the first stent comprises a network of struts forming cells, and wherein the cells have varying sizes.

[0182] Example 10: The system of any example herein, in particular example 9, wherein the cells increase in size along a length of the first stent.

[0183] Example 11: The system of any example herein, in particular example 9, wherein the first stent comprises a first portion, a second portion, and a third portion arranged in series along a length of the first stent, and wherein cells of the second portion are larger than cells of the first portion.

[0184] Example 12: The system of any example herein, in particular example 11, wherein cells of the third portion are larger than cells of the second portion.

[0185] Example 13: The system of any example herein, in particular example 9, wherein the first stent increases in width along a length of the first stent.

[0186] Example 14: The system of any example herein, in particular example 13, wherein the first stent comprises a first portion, a second portion, and a third portion arranged in series along a length of the first stent, and wherein the second portion has a greater width than the first portion.

[0187] Example 15: The system of any example herein, in particular example 14, wherein the third portion has a greater width than the second portion.

[0188] Example 16: The system of any example herein, in particular example 14, wherein cells of the second portion are larger than cells of the first portion.

[0189] Example 17: The system of any example herein, in particular example 13, wherein the width of the first stent increases gradually between a first end of the first stent and a second end of the first stent.

[0190] Example 18: The system of any example herein, in particular example 13, wherein the width of the first stent increases in a stepwise manner.

[0191] Example 19: A method comprising percutaneously delivering a first stent to a first blood vessel, wherein the first stent has a first major axis and a first minor axis, and wherein the first major axis is larger than the first minor axis.

[0192] Example 20: The method of any example herein, in particular example 19, further comprising percutaneously delivering a second stent to a second blood vessel, wherein the second blood vessel branches from the first blood vessel, and wherein the second stent is rotationally offset relative to the first stent.Docket No.: ADV-23439WO01

[0193] Example 21: A compliant stent for attenuating waves in a pulmonary artery, the stent comprising: a first portion sized for placement in a pulmonary artery, the first portion having a first major axis and a first minor axis, wherein the first major axis is larger than the first minor axis; and a second portion sized for placement in the pulmonary artery or a second blood vessel that branches from the pulmonary artery, the second portion having a second major axis and a second minor axis, wherein the second major axis is larger than the second minor axis, wherein the second portion is angled relative to the first portion.

[0194] Example 22: The stent of any example herein, in particular example 21, wherein the second portion is at an approximately 45-degree angle relative to the first portion.

[0195] Example 23: The stent of any example herein, in particular example 21, wherein the second portion is coupled to the first portion.

[0196] Example 24: The stent of any example herein, in particular example 21, wherein the second portion is rotationally offset relative to the first portion.

[0197] Depending on the example, certain acts, events, or functions of any of the processes or algorithms described herein can be performed in a different sequence, may be added, merged, or left out altogether. Thus, in certain examples, not all described acts or events are necessary for the practice of the processes.

[0198] Conditional language used herein, such as, among others, “can,” “could,” “might,” “may,” “e.g.,” and the like, unless specifically stated otherwise, or otherwise understood within the context as used, is intended in its ordinary sense, and is generally intended to convey that certain examples include, while other examples do not include, certain features, elements, and / or steps. Thus, such conditional language is not generally intended to imply that features, elements, and / or steps are in any way required for one or more examples or that one or more examples necessarily include logic for deciding, with or without author input or prompting, whether these features, elements and / or steps are included or are to be performed in any particular example. The terms “comprising,” “including,” “having,” and the like are synonymous, are used in their ordinary sense, and are used inclusively, in an open-ended fashion, and do not exclude additional elements, features, acts, operations, and so forth. Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y and Z,” unless specifically stated otherwise, is understood with the context as used in general to convey that an item, term, element, etc. may be either X, Y or Z.Docket No.: ADV-23439WO01 Thus, such conjunctive language is not generally intended to imply that certain examples require at least one of X, at least one of Y and at least one of Z to each be present.

[0199] It should be appreciated that in the above description of examples, various features are sometimes grouped together in a single example, Figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that any claim require more features than are expressly recited in that claim. Moreover, any components, features, or steps illustrated and / or described in a particular example herein can be applied to or used with any other example(s). Further, no component, feature, step, or group of components, features, or steps are necessary or indispensable for each example. Thus, it is intended that the scope of the inventions herein disclosed and claimed below should not be limited by the particular examples described above, but should be determined only by a fair reading of the claims that follow.

[0200] It should be understood that certain ordinal terms (e.g., “first” or “second”) may be provided for ease of reference and do not necessarily imply physical characteristics or ordering. Therefore, as used herein, an ordinal term (e.g., “first,” “second,” “third,” etc.) used to modify an element, such as a structure, a component, an operation, etc., does not necessarily indicate priority or order of the element with respect to any other element, but rather may generally distinguish the element from another element having a similar or identical name (but for use of the ordinal term). In addition, as used herein, indefinite articles (“a” and “an”) may indicate “one or more” rather than “one.” Further, an operation performed “based on” a condition or event may also be performed based on one or more other conditions or events not explicitly recited.

[0201] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example examples belong. It be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0202] The spatially relative terms “outer,” “inner,” “upper,” “lower,” “below,” “above,” “vertical,” “horizontal,” and similar terms, may be used herein for ease of description to describe the relations between one element or component and another element or component as illustrated in the drawings. It be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation, in additionDocket No.: ADV-23439WO01 to the orientation depicted in the drawings. For example, in the case where a device shown in the drawing is turned over, the device positioned “below” or “beneath” another device may be placed “above” another device. Accordingly, the illustrative term “below” may include both the lower and upper positions. The device may also be oriented in the other direction, and thus the spatially relative terms may be interpreted differently depending on the orientations.

[0203] Unless otherwise expressly stated, comparative and / or quantitative terms, such as “less,” “more,” “greater,” and the like, are intended to encompass the concepts of equality. For example, “less” can mean not only “less” in the strictest mathematical sense, but also, “less than or equal to.”

Claims

Docket No.: ADV-23439WO01 WHAT IS CLAIMED IS:

1. An implant for enhancing blood flow through a patient’s arterial system, comprising: a first stent sized for placement in a first blood vessel, the first stent having a first major axis and a first minor axis, wherein the first major axis is larger than the first minor axis; and a second stent sized for placement in a second blood vessel that branches from the first blood vessel, the second stent having a second major axis and a second minor axis, wherein the second major axis is larger than the second minor axis, wherein the second stent is rotationally offset relative to the first stent.

2. The system of claim 1, wherein the first stent is sized for placement in a pulmonary artery.

3. The system of claim 1 or claim 2, further comprising a third stent sized for placement in a third blood vessel that branches from the first blood vessel, wherein the third stent is rotationally offset relative to the first stent.

4. The system of claim 3, wherein the third stent is rotationally offset relative to the second stent.

5. The system of claim 1 or claim 2, wherein the first stent has an oval shape.

6. The system of claim 1 or claim 2, wherein the first stent has a generally peanut shaped cross-section.

7. The system of claim 1 or claim 2, wherein the first stent comprises a network of struts forming cells, and wherein the cells have varying sizes.

8. The system of claim 7, wherein the cells increase in size along a length of the first stent.

9. The system of claim 7, wherein the first stent comprises a first portion, a second portion, and a third portion arranged in series along a length of the first stent, and wherein cells of the second portion are larger than cells of the first portion.Docket No.: ADV-23439WO01 10. The system of claim 9, wherein cells of the third portion are larger than cells of the second portion.

11. The system of claim 7, wherein the implant is adapted to facilitate attenuation of wave reflections within the patient’s bloodstream.

12. A compliant stent for improving blood flow, comprising: a frame having a biased non-circular cross-sectional shape and including a first portion, a second portion, and a third portion arranged in series along a length of the frame, and wherein the second portion has a greater width than the first portion; wherein the cross-sectional shape is selected to attenuate upstream pressure waves in a patient’s bloodstream.

13. The stent of claim 12, wherein the third portion has a greater width than the second portion.

14. The stent of claim 13, wherein cells of the second portion are larger than cells of the first portion.

15. The stent of claim 12 or claim 13, wherein the width of the frame increases gradually between a first end of the frame and a second end of the frame.

16. The stent of claim 12 or claim 13, wherein the width of the frame increases in a stepwise manner.

17. A compliant stent for attenuating waves in a pulmonary artery, the stent comprising: a first portion sized for placement in a pulmonary artery, the first portion having a first major axis and a first minor axis, wherein the first major axis is larger than the first minor axis; and a second portion sized for placement in the pulmonary artery or a second blood vessel that branches from the pulmonary artery, the second portion having a second major axis and a second minor axis, wherein the second major axis is larger than the second minor axis, wherein the second portion is angled relative to the first portion.Docket No.: ADV-23439WO01 18. The stent of claim 17, wherein the second portion is at an approximately 45- degree angle relative to the first portion.

19. The stent of claim 17 or claim 18, wherein the second portion is coupled to the first portion.

20. The stent of claim 17 or claim 18, wherein the second portion is rotationally offset relative to the first portion.

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