Aortic dissection blocking membrane and aortic dissection system for remodelling and treating blood flow within a false lumen

Abstract

The invention relates to an aortic dissection blocking membrane (10) comprising a blocking membrane arranged to be placed in a false lumen of an aortic arch (1) associated with an aortic dissection, wherein the blocking membrane is arranged to provide a blockage to the free flow of blood in the false lumen by being foldable and / or by comprising a plurality of protrusions (11). The invention further relates to an aortic dissection system for treating blood flow within a false lumen of an aortic arch (1) associated with an aortic dissection.

Description

[0001] Aortic dissection blocking membrane and aortic dissection system for remodelling and treating blood flow within a false lumen.

[0002] TECHNICAL FIELD

[0003] The invention relates to an aortic dissection blocking membrane comprising a blocking membrane arranged to be placed in a false lumen of an aortic arch associated with an aortic dissection and an aortic dissection system for treating blood flow within a false lumen of an aforementioned aortic arch associated with an aortic dissection.

[0004] BACKGROUND ART

[0005] The aorta is the largest vessel in the human body through which approximately 200 million liters of blood circulate during a lifetime.

[0006] The aortic wall comprises three layers: the thin tunica intima that faces the bloodstream, the thick musculo-elastic tunica media, and the outer fibrous tunica externa or adventitia.

[0007] Aortic wall failure results from a broad range of disorders such as trauma and hypertensive emergencies, or chronic conditions such as chronic arterial hypertension, connective tissue disorders, inflammatory vasculitis and atherosclerosis.

[0008] Aortic dissection (AD) is a life-threatening condition which may be rapidly fatal if not detected and treated promptly. It is considered a complex vascular scenario that benefits in terms of prognosis from a rapid diagnosis and advanced teamwork including cardiac surgeons, cardiologists, vascular interventionists, and radiologists.

[0009] In type A aortic dissection (TAAD), a tear in the intima layer results in blood entry to the media layer, developing in an intimal flap and dividing the blood flow through the true and false lumens.

[0010] This tear in the inner layer allows blood to enter through the tear and fill up between the inner and middle layers, causing these layers to separate or "dissect". In the long term, owing to the inherent morbidity and mortality of this condition, it is not desirable to have a remaining false lumen. Population-based studies in the US and Europe indicate an incidence of 2.6 to 3.5 cases per 100 000 person-years. Another study from the UK observed 92 728 patients over 10 years and reported a higher incidence (6 per 100000 person-years) of acute aortic dissection, which is similar to data from Sweden with an incidence of 7.2 per 100 000 person-years.

[0011] Long term complications after TAAD surgery might include aortic growth, stroke, visceral malperfusion among others.

[0012] SUMMARY OF THE INVENTION

[0013] An object of the present disclosure is to provide an aortic dissection blocking membrane and an aortic dissection system for treating blood flow within a false lumen of an aortic arch associated with an aortic dissection that seeks to mitigate, alleviate, or eliminate one or more of the aboveidentified deficiencies in the art and disadvantages singly or in any combination.

[0014] This object is obtained by an aortic dissection blocking membrane arranged to be placed in a false lumen of an aortic arch associated with an aortic dissection. The blocking membrane is arranged to provide a blockage to the free flow of blood in the false lumen by being foldable and / or by comprising a plurality of protrusions.

[0015] By blocking the free flow of blood in the false lumen, treating the tear, and adapting the aortic layers in the aortic arch, thrombosis and remodelling of the false lumen will promote a partial or even total healing of the aortic wall. This will reduce or eliminate the false lumen, thereby maintaining blood flow only through the true lumen. With the membrane in place, turbulence increases the loss of energy of the blood flow through friction. Consequently, blood flow, velocity, and pressure in the false lumen of the aortic arch will drastically decrease and these changes might lead to complete thrombus formation in the false lumen and thereto remodelling of the remaining dissected aortic wall. It is expected that the incidence of stroke will decrease in the long term when the membrane has been used to repair the aortic dissection.

[0016] That the membrane comprises protrusions alone or in combination with the membrane being foldable will provide a good way of blocking the free flow of blood. It is important that the membrane in some way provides a blockage to the free flow of blood in the false lumen. A membrane having a smooth surface will not create enough resistance to the blood flow to achieve the desired effect of the membrane of the invention. The blocking membrane may comprise a plurality of protrusions on either side of the membrane to provide the blockage of free flow of blood in the false lumen. By having protrusions on either side of the blocking membrane, the blockage of free flow of blood can be increased.

[0017] The plurality of protrusions on the blocking membrane may be arranged in a maze-like pattern. By having the protrusions on the blocking membrane arranged in such a way, the blocking effect can be increased as all of the blood in the false lumen will encounter several obstacles that reduce blood flow, velocity and pressure.

[0018] The plurality of protrusions on the blocking membrane may be pleats. In this way, it is easy to design a blocking membrane leading to a good reduction in blood flow, velocity, and pressure in the false lumen.

[0019] The plurality of protrusions may have a height of between approximately 1 mm to 10 mm. This has shown to be effective heights for achieving the desired effect. The height can be chosen depending on the size of the false lumen. Not all protrusions need to be of the same height, the height may be different for different protrusions.

[0020] It is expected that the blocking membrane will cover as much area of the false lumen as possible in the dissected aortic arch, without compromising the exit of the aortic arch vessels. The membrane can be trimmed and cut as needed.

[0021] The object is further obtained by an aortic dissection system for treating blood flow within a false lumen of an aortic arch associated with an aortic dissection, the aortic dissection system comprising:

[0022] - an inner pledget arranged to be secured to an inner wall of a true lumen of the aortic arch adjacent the false lumen associated with the aortic dissection,

[0023] - a blocking membrane arranged to be placed in the false lumen of the aortic arch associated with the aortic dissection, wherein the blocking membrane is arranged to provide a blockage to the free flow of blood in the false lumen of the aortic arch,

[0024] - an outer pledget arranged to be secured to an outer wall of the aortic arch adjacent the false lumen associated with the aortic dissection, wherein the inner pledget and outer pledget are arranged in relation to the blocking membrane such that the blocking membrane is secured in place in the false lumen with sutures running through the inner pledget, the blocking membrane and the outer pledget as well as all layers of an aortic wall of the aortic arch associated with the aortic dissection.

[0025] By providing an aortic dissection system, a complete system ready for surgery is provided. The surgeon can from the system adapt each part to the patient and will not have to have several packages with material in store. The system is easily transportable and storable. The pledgets provide a stable material in which to fix the sutures as it may be difficult to place sutures in the aortic wall of the true lumen. By using pledgets, the number of stitches can also be reduced, reducing the time needed to perform the procedure.

[0026] The sutures may be inside out, transmural non-absorbable sutures. In this way, all layers of the aortic wall are kept in their proper place for the system to achieve its effect.

[0027] The inner and outer pledget may be made of glutaraldehyde treated bovine pericardial patch, polyethylene terephthalate or Gore-Tex®. The pledgets are to be flexible and simultaneously hard enough to achieve a longer and wider fixation surface using less sutures. One or more pledgets can be placed on the inside and the outside of the aortic arch.

[0028] The blocking membrane and pledgets may be made of a biological material, a plastic material, a synthetic fibre material or a composite material. The membrane and pledgets can be made of any material that is compatible with living tissue.

[0029] The blocking membrane may be foldable to provide the blockage of free flow of blood in the false lumen associated with the aortic dissection. By folding the blocking membrane, the area that the blood flow encounters can increase to provide a greater blocking effect.

[0030] The blocking membrane comprises a plurality of protrusions on either side of the membrane to provide the blockage of free flow of blood in the false lumen associated with the aortic dissection. By having protrusions on either side of the blocking membrane, the blockage of free flow of blood can be increased.

[0031] The plurality of protrusions on the blocking membrane may be arranged in a maze-like pattern. By having the protrusions on the blocking membraned membrane arranged in such a way, the blocking effect can be increased as all of the blood in the false lumen will encounter several obstacles that consequently will reduce blood flow, velocity and pressure. The plurality of protrusions on the blocking membrane may be pleats. In this way, it is easy to design a blocking membrane leading to a good reduction in blood flow, velocity, and pressure in the false lumen.

[0032] The plurality of protrusions may have a height of between approximately 1 mm to 10 mm. This has shown to be effective heights for achieving the desired effect. The height can be chosen depending on the size of the false lumen.

[0033] BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 schematically shows an aortic arch with the tunica adventitia partially removed and an aortic dissection blocking membrane according to one embodiment of the invention,

[0035] Figure 2 schematically shows the aortic dissection blocking membrane according to a first embodiment inserted onto the tunica media of the aortic arch ready to be fastened,

[0036] Figure 3 schematically shows a pledget being placed in the aortic arch for fastening to the tunica intima,

[0037] Figure 4 schematically shows how the tunica intima of the aortic arch is placed on the tunica media,

[0038] Figure 5 schematically shows a close up of the pledget in the tunica intima fastened with sutures,

[0039] Figure 6 schematically shows a pledget placed on the tunica adventitia fastened with sutures,

[0040] Figure 7 schematically shows a second pledget placed on the tunica adventitia fastened with sutures,

[0041] Figure 8 schematically shows a repaired aortic arch with the ascending aorta (parts of the tunica adventitia) replaced with a tube graft,

[0042] Figure 9 schematically shows the aortic dissection blocking membrane according to a second embodiment inserted onto the tunica media of the aortic arch ready to be fastened,

[0043] Figure 10 schematically shows the aortic dissection blocking membrane according to a third embodiment inserted onto the tunica media of the aortic arch ready to be fastened. DETAILED DESCRIPTION

[0044] Aspects of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. The apparatus disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

[0045] The terminology used herein is for the purpose of describing particular aspects of the disclosure only and is not intended to limit the disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise.

[0046] There are two types of aortic dissection (AD). Type A aortic dissection (TAAD) occurs when the tear develops in the ascending part of the aorta (most proximal to the heart) just above the aortic valve. TAAD can include the arch and descending aorta part. Type B aortic dissection (TBAD) involves the lower aorta (descending thoracic aorta). While Type A dissection is the more dangerous form, chances of survival are significantly improved with early detection and surgical management. However, if the blood goes through the outside aortic wall, aortic dissection is often deadly. Mortality is still high despite advances in diagnostic and therapeutic modalities.

[0047] An aortic dissection is caused by a weakened area of the aorta's wall. The fate of the chronic remaining false lumen has raised worldwide interest last decades, because of the need of considerably increase in the rate of re-intervention surgeries to reduce morbidity and mortality associated with dissection of the aorta.

[0048] The present invention relates to the use of a specially designed membrane to be used in a false lumen during aortic arch surgery, and a system comprising the membrane and a pledget that is used to fixate all aortic wall layers with the help of a surgical suture. The new surgical method for remodelling of the false lumen in TAAD is not time consuming and easy to perform.

[0049] All figures are schematic representations of an aortic arch, and some parts of the aortic arch may not be seen in all figures. Some positions of the various parts of the aortic arch are exaggerated for illustrative purpose.

[0050] Figure 1 schematically shows an aortic arch 1 with its tunica adventitia 2 partially removed and an aortic dissection blocking membrane 10 according to one embodiment of the invention. In figure 1, the aortic arch 1 has a part of the tunica adventitia 2 of the ascending aorta 3 removed such as to illustrate a state during aortic dissection surgery when it is suitable to insert the aortic dissection blocking membrane 10 into the aortic arch 1.

[0051] In figure 1, the aortic dissection blocking membrane 10 comprises a blocking membrane arranged to be placed in a false lumen of the aortic arch associated with an aortic dissection. The blocking membrane is foldable and may comprise a plurality of protrusions 11 on its surface 10a. In the example embodiment of figure 1, the protrusions 11 are raised bars arranged to provide a blockage to the free flow of blood in the false lumen.

[0052] The protrusions 11 of the aortic dissection blocking membrane 10 are in the figure arranged in a maze-like pattern, meaning that there is little to no free path for blood to flow from one short end 12 of the aortic dissection blocking membrane 10 to the second short end 13. Instead, blood flowing over the aortic dissection blocking membrane 10 will always be hindered by the protrusions 11 leading to a drastic decrease of blood flow, velocity and pressure in the false lumen of the aortic arch 1.

[0053] Figure 2 schematically shows the aortic dissection blocking membrane 10 according to a first embodiment inserted onto the tunica media 4 of the aortic arch l ready to be fastened. In figure 2, the aortic dissection blocking membrane 10 is placed on the tunica media 4 covering the area of the aortic dissection.

[0054] Figure 3 schematically shows a first or inner pledget 20a being placed in the aortic arch 1 for fastening to the tunica intima 5. In order to attach the aortic dissection blocking membrane 10 properly, pledgets 20a, 20b are used. A first pledget 20a is placed on the tunica intima 5 in a position corresponding to the placement of the aortic dissection blocking membrane 10 on the tunica media 4 as seen in figure 2. Using the first pledget 20a simplifies the suturing or coaptation of the aortic dissection blocking membrane 10 as it is difficult to suture the tunica intima 5 directly. Further, the first pledget 20a allows for fewer sutures being necessary in order to achieve the desired result.

[0055] Figure 4 schematically shows how the tunica intima 5 of the aortic arch 1 is placed on the tunica media 4. Figure 5 schematically shows a close up of the first pledget 20a in the tunica intima 5 fastened with sutures 21. As can be seen, the first pledget 20a is now attached to the tunica intima 5 with the sutures 21 passing through the first pledget 20, the tunica intima 5, the aortic dissection blocking membrane 10 and the tunica media 4.

[0056] Figure 6 schematically shows a second or outer pledget 20b placed on the tunica adventitia 2 fastened with sutures 21. In order to finally attach the aortic dissection blocking membrane 10, a second pledget 20b is placed on the tunica adventitia 2 corresponding to the placement of the aortic dissection blocking membrane 10 on the tunica media 4 as seen in figure 2 and is fastened using the sutures 21 originating from the first pledget 20a in the tunica intima 5 as shown in figure 3.

[0057] Figure 7 schematically shows an additional outer pledget 20c placed on the tunica adventitia 2 fastened with sutures 22. If necessary, an additional outer pledget 20c can be used to further fasten the aortic dissection blocking membrane 10. In such case, an additional corresponding inner pledget (not shown) is used also on the tunica intima 5 in a corresponding position.

[0058] Figure 8 schematically shows a repaired aortic arch 1 with parts of the tunica adventitia 2 replaced with a tube graft 30. This is the final stage of the aortic dissection surgery.

[0059] Figure 9 schematically shows the aortic dissection blocking membrane 10 according to a second embodiment inserted onto the tunica media 4 of the aortic arch 1 ready to be fastened. In the second embodiment, the aortic dissection blocking membrane 10 comprises a pleated configuration, where the aortic dissection blocking membrane 10 is folded numerous times so that the entire surface 10a is pleated.

[0060] Figure 10 schematically shows the aortic dissection blocking membrane 10 according to a third embodiment inserted onto the tunica media 4 of the aortic arch 1 ready to be fastened. In the third embodiment, the aortic dissection blocking membrane 10 comprises a number of circular protrusions 11 arranged on the surface 10a of the aortic dissection blocking membrane 10. As is shown in figure 1, the circular protrusions 11 are arranged in a maze-like pattern such that there is very little to no free path for blood to flow from one short end 12 of the aortic dissection blocking membrane 10 to the second short end 13. It is also possible for a part of the surface 10a to be folded into pleats with the remaining part of the surface 10a comprising other types of protrusions such as the ones described herein.

[0061] As described in the figures, the blocking membrane is placed within the false lumen of the aortic arch 1 and fastened with surgical pledgets 20a-20c and surgical non-absorbable sutures 21, 22. The blocking membrane may comprise protrusions 11 on one or both surfaces 10a that are between approximately 1 mm to 10 mm in height, specifically approximately 2 mm to 6 millimeters in height. The membrane can be made of any size in width, thickness and length and can be cut to a desired size before placement as the false lumen size can largely vary from case to case. One example size is 60-100 mm wide, 0.5-1.5 mm thick (with protrusions 11 extending above this surface) and 120-160 mm long, specifically 80 mm wide, 1 mm thick (with protrusions 11 extending above this surface) and 140 mm long. The protrusions 11 are organized in such a way that the remaining blood flow circulating in the false lumen will always have an obstacle to the free blood flow, for instance resembling a maze, thereby decreasing blood flow velocity and pressure. This will further increase the probability of clot formation, healing and consequently disappearance of the false lumen.

[0062] The blocking membrane placed in the false lumen will also help to stabilize the fragile tissues and highly interfere with the blood flow in the dissected aortic arch 1. Because of the consequently low flow conditions after placing the membrane, it is expected clot formation in the false lumen, i.e. by the end of surgery after giving protamine or later on.

[0063] Low blood flow and pressure within the false lumen is assumed to be beneficial as well, since this will enhance the endothelialization process of this device, conversely the high pressure and high flow might explain the difficulties for endothelialization of the inner arterial dacron graft wall.

[0064] The pledgets 20a-20c, like the blocking membrane, can be made in any size in width, thickness, or length. Example sizes are 20-30 mm wide, 2-4 mm thick and 30 - 50 mm long, specifically 23- 27 mm wide, 2.5-3.5 mm thick and x 35-45 mm long.

[0065] The characteristics of the pledgets 20a-20c are to be flexible and simultaneously hard enough to achieve a longer and wider fixation surface using less sutures. Inner pledget 20a and possibly one or more additional inner pledgets help stabilize and secure the extremely fragile tunica intima.

[0066] Pledgets can be prepared in different numbers and sizes as needed before or during surgery and as described above at least a first pledget 20a is placed in the true lumen of the aortic arch 1 and fastened / secured with inside out transmural non absorbable sutures, (i.e. Prolene®, Ethicon 4-0) including in the following sequence, the tunica intima, the inter-positioned membrane, the tunica media and out through the outer aortic layer called tunica adventitia, ending in another pledget 20b located ipsilateral outside the aortic wall.

[0067] In this way, the sutures secure all aortic layers including the inter-positioned membrane in the false lumen.

[0068] The blocking membrane and pledget are made of materials such as for instance glutaraldehyde treated bovine pericardial patch, polyethylene terephthalate or Gore-Tex®.

[0069] Throughout the description and claims of this specification, the words "comprise" and "contain" and variations of them mean "including but not limited to", and they are not intended to (and do not) exclude other components, integers, or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0070] Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS1. Aortic dissection blocking membrane (10) arranged to be surgically fastened in a false lumen of an aortic arch (1) associated with an aortic dissection, wherein the blocking membrane (10) is arranged to provide a blockage to the free flow of blood in the false lumen by being foldable and / or by comprising a plurality of protrusions (11).

2. The aortic dissection blocking membrane (10) of any one of the preceding claims, wherein the blocking membrane (10) comprises a plurality of protrusions (11) on either side (10a) of the blocking membrane to provide the blockage of free flow of blood in the false lumen.

3. The aortic dissection blocking membrane (10) of any one of the preceding claims, wherein the plurality of protrusions on the blocking membrane (10) are arranged in a maze-like pattern.

4. The aortic dissection blocking membrane (10) of any one of claims 1-3, wherein the plurality of protrusions (11) on the blocking membrane (10) are pleats.

5. The aortic dissection blocking membrane (10) of any one of the preceding claims, wherein the plurality of protrusions (11) has a height of between approximately 1 mm to 10 mm.

6. An aortic dissection system for treating blood flow within a false lumen of an aortic arch (1) associated with an aortic dissection, the aortic dissection system comprising:- an inner pledget (20a) arranged to be secured to an inner wall of a true lumen of the aortic arch (1) adjacent the false lumen associated with the aortic dissection,- an aortic dissection blocking membrane (10) arranged to be placed in the false lumen of the aortic arch (1) associated with the aortic dissection, wherein the blocking membrane (10) is arranged to provide a blockage to the free flow of blood in the false lumen of the aortic arch (1),- an outer pledget (20b) arranged to be secured to an outer wall of the aortic arch (1) adjacent the false lumen associated with the aortic dissection,wherein the inner pledget (20a) and outer pledget (20b) are arrangable in relation to the blocking membrane (10) such that the blocking membrane (10) is secured in place in the false lumen with sutures (21, 22) running through the inner pledget (20a), the blocking membrane (10) and the outer pledget (20b) as well as all layers of an aortic wall of the aortic arch (1) associated with the aortic dissection.

7. The aortic dissection system of claim 6, wherein the sutures (21, 22) are inside out, transmural non-absorbable sutures.

8. The aortic dissection system of claim 6 or 7, wherein the inner and outer pledgets (20a, 20b) are made of glutaraldehyde treated bovine pericardial patch, polyethylene terephthalate or Gore-Tex®.

9. The aortic dissection system of any one of the preceding claims 6-8, wherein the blocking membrane (10) is made of a biological material, a plastic material, a synthetic fibre material or a composite material.

10. The aortic dissection system of any one of the preceding claims 6-9, wherein the blocking membrane (10) is foldable to provide the blockage of free flow of blood in the false lumen associated with the aortic dissection.

11. The aortic dissection system of any one of the preceding claims 6-10, wherein the blocking membrane (10) comprises a plurality of protrusions (11) on either side (10a) of the blocking membrane (10) to provide the blockage of free flow of blood in the false lumen associated with the aortic dissection.

12. The aortic dissection system of any one of the preceding claims 6-11, wherein the plurality of protrusions (11) on the blocking membrane (10) are arranged in a mazelike pattern.

13. The aortic dissection system of any one of the preceding claims 6-11, wherein the plurality of protrusions (11) on the blocking membrane (10) are pleats.

14. The aortic dissection system of any one of the preceding claims 6-13, wherein the plurality of protrusions (10) has a height of between approximately 1 mm to 10 mm.

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