Blood pump assembly comprising sensor and sensor shield

Abstract

To provide a blood pump assembly.SOLUTION: A blood pump assembly may comprise various components such as, a housing, and a sensor configured to detect one or more characteristics of blood. In some embodiments, the sensor may be coupled to the housing, and may include a sensor membrane configured to be bent in response to change of a blood parameter (pressure, for example). The blood pump assembly may include a shield for covering at least a part of the sensor membrane, so as to protect the sensor from damage, when the blood pump assembly is inserted through an introducer, and is advanced through a vasculature of the patient, and / or the blood pump assembly is inserted into a heart in a surgical technique. For preventing dissolution of the sensor membrane by interaction with the blood of the patient, one or more protection layers may provided on the sensor membrane.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Provisional Patent Application No. 62 / 346,163, filed June 6, 2016, the entire contents of which are incorporated herein by reference. [Background technology]

[0002] background A blood pump assembly, such as an intracardiac blood pump assembly, may be introduced into the heart to deliver blood from the heart into the arteries. Various blood pump assemblies draw blood from the left ventricle of the heart and eject blood into the aorta. Some blood pump assemblies support the left side of the heart and may be introduced percutaneously through the vascular system during a cardiac procedure, such as by a catheter procedure through the femoral artery into the ascending aorta and across the aortic valve into the left ventricle. In systems intended to support the right side of the heart, the blood pump assembly may be introduced through a vein and inserted into the heart through the venous system (i.e., the vena cava). Blood pump assemblies for either side of the heart may also be surgically implanted or inserted through the subclavian and / or carotid arteries.

[0003] Tortuous pathways and / or calcified anatomical structures can obstruct and damage components of the blood pump assembly as it is inserted through the blood vessels. If the blood pump assembly is damaged during insertion, it may require removal or replacement of the blood pump assembly. Because the blood pump assembly is designed for use in procedures that affect the vitality of the patient, it is important that it can be precisely manipulated and delivered. Additionally, it can be important to monitor the patient's interaction with the blood pump assembly. Summary of the Invention

[0004] overview In one aspect, a blood pump assembly includes a blood pump housing component, at least one input port and at least one outlet port, and a sensor coupled to the blood pump housing component. The sensor includes a sensor membrane configured to deflect in response to a change in a blood parameter. The sensor is coupled to a transmission fiber. The blood pump assembly includes a shield covering at least a portion of the sensor membrane to protect the sensor from physical damage.

[0005] In some embodiments, the shield includes a barrier bump positioned distally relative to the sensor membrane. In certain embodiments, the blood pump assembly further includes a sensor visor extending distally beyond the sensor membrane to protect the sensor from physical damage. In some embodiments, the sensor visor extends into a visor notch formed in the barrier bump. In certain embodiments, the blood pump assembly further includes a cap covering the visor notch. In some embodiments, the sensor visor is attached to the barrier bump by adhesive or welding. In certain embodiments, the shield includes at least one protective layer covering a surface of the sensor membrane. In some embodiments, the sensor membrane is recessed proximally relative to the sensor visor. In certain embodiments, the shield includes a blood aperture extending through the blood pump housing component and positioned distally relative to the sensor membrane for flushing the sensor membrane with blood.

[0006] In another aspect, a blood pump assembly includes a blood pump housing component, a cannula assembly coupled to the blood pump housing component, and a sensor coupled to the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter and coupled to a transmission fiber, and the blood pump assembly includes a passive protection mechanism to protect the sensor from damage when the blood pump assembly is inserted into a patient.

[0007] In some embodiments, the passive protection mechanism includes a barrier positioned distal to the sensor membrane. In certain embodiments, the barrier protrudes from the blood pump housing component. In some embodiments, the barrier is constructed of the same material as the blood pump housing component. In certain embodiments, the barrier has a smooth outer surface that contacts the blood. In some embodiments, the barrier has a radial height that is approximately equal to or greater than the radial height of the sensor. In certain embodiments, the blood pump assembly further includes one or more protective layers attached on a surface of the sensor membrane that faces toward the distal end of the blood pump assembly. In some embodiments, the one or more protective layers include a single layer, the single layer being formed of a material that is attached on the sensor membrane and that is adherent and curable as a gel. In certain embodiments, the one or more protective layers include a material that can prevent the sensor membrane from dissolving due to a chemical or biological reaction with blood. In some embodiments, the one or more protective layers include a layer of silicone. In certain embodiments, the one or more protective layers include a metal oxide. In some embodiments, the sensor membrane has a thickness of 2 microns or less. In certain embodiments, the sensor is positioned within a sensor bed in the blood pump housing component. In some embodiments, the sensor is an optical sensor that transmits an optical signal.In certain embodiments, the blood pump housing component has a substantially cylindrical and elongated shape.

[0008] In another aspect, a blood pump assembly includes a drive unit, an impeller blade, a blood pump housing component, a cannula assembly, and a sensor. The cannula assembly is coupled to the blood pump housing component. The blood pump housing component includes a circumferential wall extending about an axis of rotation of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the circumferential wall of the blood pump housing component. The sensor includes a sensor membrane configured to deflect in response to a change in a blood parameter. The sensor membrane is coupled to a transmission fiber. The blood pump assembly includes a shield covering at least a portion of the sensor membrane.

[0009] In some embodiments, the shield includes a barrier bump positioned distal to the sensor membrane and a sensor visor overhanging the sensor membrane. In certain embodiments, the sensor visor extends to the barrier bump. In some embodiments, the sensor visor extends into a visor notch of the barrier bump. In some embodiments, a cap covers the visor notch. In certain embodiments, the sensor visor is attached to the barrier bump by an adhesive. In some embodiments, the shield includes a protective layer covering a surface of the sensor membrane. In certain embodiments, the sensor membrane is further recessed below the sensor visor by a distance approximately equal to the thickness of the protective layer. In some embodiments, the shield includes a blood aperture extending through the peripheral wall of the blood pump housing component and positioned distal to the sensor membrane for washing the sensor membrane. In certain embodiments, the blood aperture is positioned between the sensor membrane and the barrier bump. In some embodiments, the sensor visor extends over the blood aperture.

[0010] In another aspect, a blood pump assembly includes a drive unit, an impeller blade, a blood pump housing component, a cannula assembly, and a sensor. The cannula assembly is coupled to the blood pump housing component. The blood pump housing component includes a circumferential wall extending about an axis of rotation of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the circumferential wall of the blood pump housing component. The sensor includes a sensor membrane configured to deflect in response to a change in a blood parameter. The membrane is coupled to a transmission fiber. The blood pump assembly includes a sensor shield, which may be configured as a passive protection mechanism, positioned distal to the sensor membrane.

[0011] In some embodiments, the shield (e.g., passive protection mechanism) positioned distal to the sensor membrane includes a barrier positioned distal to the sensor membrane. In certain embodiments, the shield (e.g., barrier) positioned distal to the sensor membrane includes a barrier bump positioned distal to the sensor membrane. The barrier bump may protrude from a peripheral wall of the blood pump housing component. In certain embodiments, the shield (e.g., barrier or barrier bump) is composed of the same material as the blood pump housing component. In some embodiments, the shield (e.g., barrier or barrier bump) has a smooth surface. In certain embodiments, the shield (e.g., barrier or barrier bump) is composed of stainless steel. In some embodiments, the shield (e.g., barrier or barrier bump) is electropolished or mechanically polished. In certain embodiments, the shield (e.g., barrier or barrier bump) has a height approximately equal to or greater than the height of the sensor. In some embodiments, the shield (e.g., barrier or barrier bump) has a visor notch configured to receive a sensor visor that overhangs the sensor membrane.

[0012] In certain embodiments, the shield of the blood pump assembly includes a passive protection mechanism positioned such that the sensor membrane is positioned between the passive protection mechanism and a peripheral wall of the blood pump housing component. In some embodiments, the shield (e.g., the passive protection mechanism) positioned such that the sensor membrane is between the shield and the peripheral wall of the blood pump housing includes a barrier positioned such that the sensor membrane is between the barrier and the peripheral wall of the blood pump housing. In certain embodiments, the shield (e.g., the barrier) positioned such that the sensor membrane is between the shield and the peripheral wall of the blood pump housing includes a sensor visor overhanging the sensor membrane. In some embodiments, the sensor visor is stainless steel. In certain embodiments, the sensor visor has a smooth surface. In some embodiments, the sensor visor includes a biocompatible material. In certain embodiments, the sensor visor is coated with a biocompatible material.

[0013] In another aspect, a blood pump assembly includes a drive unit, an impeller blade, a blood pump housing component, a cannula assembly, and a sensor. The cannula assembly is coupled to the blood pump housing component. The blood pump housing component includes a circumferential wall extending about an axis of rotation of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the circumferential wall of the blood pump housing component. The sensor includes a sensor membrane configured to deflect in response to a change in a blood parameter. The membrane is coupled to a transmission fiber. The blood pump assembly includes a sensor shield, which may be configured as a passive protection mechanism covering a surface of the sensor membrane.

[0014] In some embodiments, the shield (e.g., a passive protection mechanism) covering the surface of the sensor membrane includes a barrier covering the surface of the sensor membrane. In certain embodiments, the shield (e.g., a barrier) covering the surface of the sensor membrane includes a protective layer deposited on the surface of the sensor membrane. In some embodiments, the sensor membrane faces toward the distal end of the blood pump assembly, and the protective layer deposited on the surface of the sensor membrane is deposited on the surface of the sensor membrane facing toward the distal end of the blood pump assembly. In certain embodiments, the protective layer has a thickness approximately equal to or greater than 0.03 mm. In some embodiments, the protective layer has a thickness approximately equal to or greater than 0.13 mm. In certain embodiments, the protective layer includes a material that can be deposited as a gel and hardened. In some embodiments, the protective layer includes a material that can prevent the sensor membrane from dissolving due to a chemical reaction with blood. In certain embodiments, the protective layer includes silicone.

[0015] In another aspect, a blood pump assembly includes a drive unit, an impeller blade, a blood pump housing component, a cannula assembly, and a sensor. The cannula assembly is coupled to the blood pump housing component. The blood pump housing component includes a circumferential wall extending about an axis of rotation of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the circumferential wall of the blood pump housing component. The sensor includes a sensor membrane configured to deflect in response to a change in a blood parameter. The membrane is coupled to a transmission fiber. The blood pump assembly includes a sensor shield, which may be configured as one or more active protection mechanisms for the sensor membrane.

[0016] In some embodiments, the shield (e.g., one or more active protection mechanisms) includes a mechanism for cleaning the sensor membrane, such as, for example, a mechanism for cleaning the sensor membrane with blood. In some embodiments, the mechanism for cleaning the sensor membrane includes one or more components, such as a blood aperture extending through the peripheral wall of the blood pump housing component and positioned distally to the sensor membrane. In certain embodiments, the peripheral wall of the blood pump housing component includes a recess positioned distally to the sensor membrane. In some embodiments, the recess is wider than the sensor. In certain embodiments, the blood aperture is positioned within the recess. In some embodiments, the blood aperture allows blood flowing through the cannula assembly into the blood pump housing component to exit the blood pump housing component and clean the sensor membrane.

[0017] In some embodiments, the peripheral wall of the blood pump housing component includes one or more blood drainage windows. In certain embodiments, the peripheral wall of the blood pump housing component includes a transmission fiber bed that is a recess in the peripheral wall of the blood pump housing component, and the transmission fiber of the sensor is positioned within the transmission fiber bed. The transmission fiber is used to transmit a signal sensed by the sensor to a processor for detecting a blood parameter. In some embodiments, the sensor includes a glass ring positioned around the transmission fiber.

[0018] In certain embodiments, the sensor membrane has a thickness of 2 microns or less. In some embodiments, the sensor membrane has a thickness of 1.3 microns or less. In certain embodiments, the sensor is positioned in a sensor bed in a peripheral wall of the blood pump housing component. In some embodiments, the blood pump housing component includes a plurality of struts extending between the blood outlet windows. The transmission fiber bed may be positioned in one of the struts of the blood pump housing component. In some embodiments, the transmission fiber may be coupled to the one of the struts by an epoxy resin. The impeller blade may be positioned at least partially within the blood pump housing component. In some embodiments, the blood pump housing component is coupled to the drive unit at a first end and to the cannula assembly at a second end opposite the first end. In certain embodiments, the cannula assembly includes a blood inflow cage. In some embodiments, the blood inflow cage includes a plurality of inlet openings. In certain embodiments, a flexible atraumatic extension (e.g., a pigtail) is coupled to the blood inflow cage.

[0019] In another aspect, a method of manufacturing a blood pump assembly includes coupling a sensor to a peripheral wall of a blood pump housing component; rotatably coupling an impeller blade to a drive unit such that the peripheral wall of the blood pump housing component extends about an axis of rotation of the impeller blade; and coupling a cannula assembly to the blood pump housing component. The sensor includes a sensor membrane configured to deflect in response to a change in a blood parameter. The sensor membrane is coupled to a transmission fiber. The sensor may include a sensor visor overhanging the sensor membrane.

[0020] In some embodiments, the method of the present invention may further include positioning the sensor visor in a visor notch of a barrier bump protruding from a peripheral wall of the blood pump housing component. In certain embodiments, coupling the sensor to the peripheral wall of the blood pump housing component may include affixing the sensor to the peripheral wall of the blood pump housing component (e.g., by epoxy resin or the like). In some embodiments, coupling the sensor to the peripheral wall of the blood pump housing component includes positioning the sensor in a blood cavity in the peripheral wall of the blood pump housing component. In certain embodiments, the blood pump housing component includes a plurality of blood evacuation windows and a plurality of struts extending between the blood evacuation windows, and the blood cavity is positioned within one of the struts in the blood pump housing component. In some embodiments, the method of the present invention further includes coupling the blood inflow cage to the cannula assembly. In certain embodiments, the method of the present invention further includes coupling a flexible atraumatic extension to the blood inflow cage. In some embodiments, a protective layer is applied on a surface of the sensor membrane. In certain embodiments, a protective layer is applied onto the surface of the sensor membrane, and the sensor membrane is further recessed below the sensor visor by a distance approximately equal to the thickness of the protective layer.

[0021] The sensor detects one or more disturbances or characteristics of the blood (e.g., pressure induced deflection used to determine the blood parameter signal). In some embodiments, the sensor is a pressure sensor or a flow sensor. In certain embodiments, the sensor transmits the sensed signal optically. In some embodiments, the transmission fiber is an optical fiber. In certain embodiments, the drive unit is driven by an external motor.

[0022] In another aspect, a method of detecting blood pressure includes pumping blood through a cannula assembly coupled to a blood pump housing component; and detecting the blood pressure of the pumped blood with an optical pressure sensor coupled to a peripheral wall of the blood pump housing component. The blood is pumped by an impeller blade positioned at least partially within the blood pump housing component. The impeller blade is rotated by a drive unit coupled to the impeller blade. The blood pump housing component includes a peripheral wall extending about an axis of rotation of the impeller blade. The optical pressure sensor includes a sensor membrane configured to deflect in response to changes in pressure on the sensor membrane. The sensor membrane is coupled to an optical fiber. The optical pressure sensor includes a sensor visor overhanging the sensor membrane.

[0023] In some embodiments, the step of pumping blood includes pumping blood through one or more blood outlet windows in the blood pump housing component. In certain embodiments, the method further includes washing the sensor membrane with blood flow through a blood aperture extending through a peripheral wall of the blood pump housing component. The blood aperture is positioned in a blood cavity positioned in front of the sensor membrane of the optical pressure sensor. In some embodiments, the peripheral wall of the blood pump housing component includes a barrier bump protruding from the peripheral wall of the blood pump housing component. The barrier bump is positioned in front of the blood cavity such that the blood cavity is between the barrier bump and the sensor membrane. In certain embodiments, the method further includes deflecting blood flowing through the blood aperture with a sensor visor extending from the optical pressure sensor onto the sensor membrane and into a visor notch in the barrier bump. In some embodiments, the sensor membrane includes a glass material. In certain embodiments, the sensor membrane faces toward the distal end of the pump. In some embodiments, the sensor membrane is less than 2 microns thick. In some embodiments, a protective layer is applied onto the surface of the sensor membrane. In certain embodiments, a protective layer is applied onto the surface of the sensor membrane, and the sensor membrane is recessed further below the sensor visor by a distance approximately equal to the thickness of the protective layer.

[0024] It should be recognized that all combinations of the foregoing concepts, and additional concepts discussed in more detail below, are contemplated as part of the inventive subject matter disclosed herein (unless such concepts are mutually inconsistent). In particular, all combinations of the subject matter of the appended claims are contemplated as part of the inventive subject matter disclosed herein. Additionally, certain concepts may be omitted or not implemented. [The present invention 1001] a blood pump housing component; at least one input port and at least one output port; a sensor coupled to the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter, the sensor coupled to a transmission fiber; Equipped with a shield covering at least a portion of the sensor membrane to protect the sensor from physical damage; Blood pump assembly. [The present invention 1002] A blood pump assembly according to the present invention 1001, wherein the shield includes a barrier bump positioned distal to the sensor membrane. [The present invention 1003] The blood pump assembly of the present invention 1002 further comprising a sensor visor for protecting the sensor from physical damage, the sensor visor extending distally beyond the sensor membrane. [The present invention 1004] A blood pump assembly according to the present invention 1003, wherein the sensor visor is attached to the barrier bump by adhesive or welding. [The present invention 1005] A blood pump assembly of the present invention 1003, wherein the sensor membrane is recessed proximally relative to the sensor visor. [The present invention 1006] A blood pump assembly according to the present invention 1003, wherein the sensor visor extends into a visor notch formed in the barrier bump. [The present invention 1007] The blood pump assembly of the present invention 1006 further comprising a cap covering the visor notch. [The present invention 1008] The blood pump assembly of the present invention 1001, wherein the shield includes at least one protective layer covering a surface of the sensor membrane. [The present invention 1009] A blood pump assembly of the present invention 1001, wherein the shield includes a blood aperture extending through the blood pump housing component and positioned distal to the sensor membrane for flushing the sensor membrane with blood. [The present invention 1010] a blood pump housing component; a cannula assembly coupled to the blood pump housing component; a sensor coupled to the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter, the sensor coupled to a transmission fiber; 1. A blood pump assembly comprising: A blood pump assembly including a passive protection mechanism for protecting the sensor from damage when the blood pump assembly is inserted into a patient. [The present invention 1011] The blood pump assembly of the present invention 1010 further comprising one or more protective layers deposited on a surface of the sensor membrane facing towards the distal end of the blood pump assembly. [The present invention 1012] A blood pump assembly of the present invention 1011, wherein the one or more protective layers include a single layer, the single layer being adhered onto the sensor membrane and formed of a material that is adherent as a gel and can harden. [The present invention 1013] A blood pump assembly according to the present invention 1011, wherein the one or more protective layers comprise a material capable of preventing dissolution of the sensor membrane due to chemical or biological reaction with blood. [The present invention 1014] A blood pump assembly according to the present invention 1011, wherein the one or more protective layers include a layer of silicone. [The present invention 1015] The blood pump assembly of the present invention 1011, wherein the one or more protective layers comprise a metal oxide. [The present invention 1016] A blood pump assembly of the present invention 1010, wherein the passive protection mechanism includes a barrier positioned distal to the sensor membrane. [The present invention 1017] A blood pump assembly according to the present invention 1016, wherein the barrier protrudes from the blood pump housing component. [The present invention 1018] A blood pump assembly according to the present invention 1016, wherein the barrier is constructed from the same material as the blood pump housing components. [The present invention 1019] A blood pump assembly according to the present invention 1016, wherein the barrier has a smooth outer surface which contacts the blood. [The present invention 1020] A blood pump assembly according to the present invention 1016, wherein the barrier has a radial height approximately equal to or greater than the radial height of the sensor. [The present invention 1021] A blood pump assembly according to the present invention 1010, wherein the sensor membrane has a thickness of 2 microns or less. [The present invention 1022] A blood pump assembly of the present invention 1010, wherein the sensor is positioned within a sensor bed within a blood pump housing component. [The present invention 1023] A blood pump assembly according to the present invention 1010, wherein the sensor is an optical sensor that transmits an optical signal. [The present invention 1024] A blood pump assembly of the present invention 1010, wherein the blood pump housing component has a substantially cylindrical and elongated shape. [The present invention 1025] Drive unit and; an impeller blade rotatably connected to the drive unit; a blood pump housing component including a peripheral wall extending about an axis of rotation of the impeller blades; a cannula assembly coupled to the blood pump housing component; a sensor coupled to the peripheral wall of the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter and coupled to a transmission fiber; Equipped with a shield configured as one or more active protection mechanisms for the sensor membrane; Blood pump assembly. [The present invention 1026] A blood pump assembly of the present invention 1025, wherein the one or more active protection mechanisms include a mechanism for cleaning the sensor membrane. [The present invention 1027] The blood pump assembly of the present invention 1026, wherein the mechanism for washing the sensor membrane includes a mechanism for washing the sensor membrane with blood. [The present invention 1028] pumping blood through a cannula assembly coupled to a blood pump housing component, the blood being pumped by impeller blades positioned at least partially within the blood pump housing component, the impeller blades being rotated by a drive unit coupled to the impeller blades, the blood pump housing component including a peripheral wall extending about an axis of rotation of the impeller blades; and detecting a blood pressure of the pumped blood with an optical pressure sensor coupled to the peripheral wall of the blood pump housing component, the optical pressure sensor including a sensor membrane configured to deflect in response to changes in pressure on the sensor membrane, the sensor membrane being coupled to an optical fiber, and the optical pressure sensor including a sensor visor overhanging the sensor membrane; 13. A method for detecting blood pressure comprising: [The present invention 1029] The method of the present invention 1028 further includes the step of washing the sensor membrane with blood flow through a blood aperture extending through a peripheral wall of the blood pump housing component, the blood aperture being positioned within a blood cavity positioned in front of the sensor membrane of the optical pressure sensor. [The present invention 1030] The method of the present invention 1029, wherein the peripheral wall of the blood pump housing component includes a barrier bump protruding from the peripheral wall of the blood pump housing component, the barrier bump being positioned in front of the blood cavity such that the blood cavity is between the barrier bump and the sensor membrane. [Brief description of the drawings]

[0025] These and other objects and advantages will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout.

[0026] [Figure 1] FIG. 1 is a side view of an exemplary catheter blood pump assembly having a sensor and exemplary shielding features for protecting the sensor. [Diagram 2] FIG. 2 is a top view of the blood pump assembly of FIG. 1. [Diagram 3] FIG. 2 is a partial top view of the blood pump assembly of FIG. 1. [Figure 4] FIG. 2 is an enlarged perspective view of a sensor installed on the outflow cage of the blood pump assembly of FIG. 1. [Diagram 5] FIG. 5 is an enlarged side view of the sensor and outflow cage of FIG. 4. [Figure 6] FIG. 5 is an enlarged end view of the blood pump assembly of FIG. 4, showing the impeller hub, impeller blades, and exemplary shielding features for protecting the sensor. [Figure 7] FIG. 5 is an enlarged end view of the sensor and shielding features of the blood pump assembly of FIG. 4. [Figure 8] FIG. 5 is a perspective view of the blood pump assembly of FIG. 4, showing the cap and cover that provide a smooth transition between the outflow cage and the shielding feature. [Figure 9] FIG. 2 is a side view of a sensing assembly for a catheter blood pump assembly. [Figure 10] FIG. 2 is a partial cross-sectional side view of a sensing assembly for a catheter-type blood pump assembly. [Figure 11] 13 is a partial cross-sectional side view of another sensing assembly including an additional protective layer covering the sensor membrane. [Figure 12] 13 is a partial cross-sectional side view of another sensing assembly including an additional protective layer covering the sensor membrane. [Figure 13] 1 is a flow diagram of an exemplary process for manufacturing a blood pump assembly. [Figure 14] 1 is a flow diagram of an exemplary process for detecting blood pressure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Detailed Description To provide an overall understanding of the blood pump assemblies, sensors, methods of manufacturing blood pump assemblies, and methods for detecting blood parameters such as pressure or flow rate as contemplated herein, certain exemplary aspects will be described. Although the aspects and features described herein are specifically described for use in connection with blood pump assemblies that may be percutaneously introduced through the vascular system during a cardiac therapy procedure, it will be understood that all components and other features outlined below may be combined with each other in any suitable manner, and may be adapted and applied to other types of cardiac therapy and cardiac therapy devices.

[0028] The systems, methods, and devices described herein provide a blood pump assembly including a sensor and a shield that protects the sensor from physical damage. The sensor may include a sensor membrane, which may be fragile. The shield may allow the blood pump assembly and the sensor to navigate tortuous paths in the vasculature and / or calcified anatomical structures and remain operable, such as by protecting the sensor membrane. The shield may include one or more passive protection mechanisms, active protection mechanisms, or a combination of both. A passive protection mechanism may include one or more barriers that protect the sensor membrane. As an example, a sensor visor may prevent soft obstacles, such as valve leaflets on the introducer of the blood pump, from contacting and damaging the sensor membrane. A barrier bump is another example of a passive protection mechanism and may be positioned distal to the sensor membrane. The barrier bump may deflect calcifications and other obstacles in the vasculature and / or prevent the sensor membrane from being damaged when the pump changes direction during delivery through the vasculature into the heart. The shield may also include an additional protective layer (e.g., a layer of silicone) covering the sensor membrane. By way of example, this protective layer may prevent the sensor membrane from dissolving due to chemical reaction with the patient's blood without significantly affecting or interfering with accurate detection of pressure. A mechanism for washing the sensor membrane is one example of an active protection mechanism for the sensor. For example, a blood aperture may be positioned adjacent to the sensor membrane to prevent blood from accumulating or clotting on the surface of the sensor membrane, and blood flowing through the aperture may wash the front end of the sensor membrane.

[0029] FIG. 1 is a side view of an exemplary catheter-based blood pump assembly 101 having a sensor 1020 and exemplary shielding features for protecting the sensor 1020. FIG. 2 is a top view of the blood pump assembly 101, and FIG. 3 is a partial top view of the blood pump assembly 101. As shown in the figures, the blood pump assembly 101 includes a cannula assembly 102, a sensor 1020, a catheter shaft 106, a flexible atraumatic extension (e.g., pigtail) 108, a blood pump motor 110, a blood pump motor housing 105, a blood pump housing component 103, a drive shaft 104, an impeller hub 113, a blood inflow cage 107, and a guidewire lumen 141. The pigtail extension 108 includes a curved portion 109. The blood inflow cage 107 includes one or more input ports 111. The interior of the blood pump housing component 103 is adjacent to the interior of the cannula assembly 102. The cannula assembly 102 is coupled to a blood pump housing component 103, which is coupled to a blood pump motor housing 105. The blood pump housing component has a substantially cylindrical and elongated shape. The blood pump motor 110 is housed within the blood pump motor housing 105. Alternatively, in certain other embodiments, the blood pump motor 110 has a one-piece housing such that the outer layer of the blood pump motor 110 is the blood pump housing 105.

[0030] As used herein, "distal" refers to the direction in which the blood pump assembly is inserted into a blood vessel, and "proximal" is the opposite of the distal direction. For example, in FIG. 1 , the extension 108 is distal to the sensor 1020, and the catheter shaft 106 is proximal to the sensor 1020.

[0031] The cannula assembly 102 includes a blood inflow cage 107 positioned toward a distal end of the cannula assembly 102 opposite the proximal blood pump housing component 103. A catheter shaft 106 extends from a blood pump motor housing 105 at the proximal end of the blood pump assembly 101. A flexible atraumatic extension (e.g., a pigtail) 108 extends distally from the blood inflow cage 107 at the distal end of the blood pump assembly 101. The blood pump assembly 101 may be configured as a left or right heart pump.

[0032] The sensor 1020 may sense blood pressure, blood flow, and / or other parameters. The sensor 1020 transmits the sensed signal to a transducer system that includes a signal conditioning and data acquisition system for linearization and calibration of the parameter to convert it to a desired physical or medical variable. For example, the sensor 1020 may be an optical pressure sensor that transmits an optical signal, or may be an electrical sensor.

[0033] The cannula assembly 102 provides at least one central lumen 114 configured to facilitate blood flow therethrough. The cannula assembly 102 includes a bend 112. In some embodiments, the bend 112 is 45°. One skilled in the art will appreciate that other configurations for the cannula assembly 102 are possible. In certain embodiments designed for use on the right side of the heart, the cannula assembly 102 may have one or more bends and may have different and / or multiple bend radii to accommodate the needs of the passage and final position of the cannula assembly 102. In certain embodiments, the cannula assembly 102 may have no bends. In certain embodiments, the diameter of the cannula assembly 102 is about equal to or greater than 9 Fr (3 mm). For example, the diameter of the cannula assembly 102 may be 9 Fr (3 mm), 10 Fr (3.33 mm), 11 Fr (3.67 mm), 12 Fr (4 mm), greater than 12 Fr, or any other suitable diameter. In some embodiments, the diameter of the cannula assembly 102 is about equal to or less than 9 Fr (3 mm). For example, the diameter of the cannula assembly 102 may be 8 Fr (2.67 mm), 7 Fr (2.33 mm), 6 Fr (2 mm), less than 6 Fr, or any other suitable diameter.

[0034] The drive shaft 104 transmits torque from the blood pump motor 110 to the impeller hub 113. For example, a proximal end portion of the drive shaft 104 (not shown) may be coupled to the rotor of the blood pump motor 110, and a distal end of the drive shaft 104 (not shown) may be coupled to the impeller hub 113. In some embodiments, a flexible drive cable, a magnetic clutch, and / or a magnetic drive component transmits torque from the blood pump motor 110 to the impeller hub 113. In certain embodiments, the blood pump motor 110 may be positioned outside the patient's body and configured to rotate the rotor of the blood pump motor 110 when the blood pump assembly 101 is positioned within the patient's heart, and a drive shaft or drive cable may be coupled to the rotor of the blood pump motor 110. In such embodiments, the blood pump motor 110 is not present within the blood pump motor housing 105. In those embodiments, the blood pump motor housing 105 is modified to reduce the stiffness of the pump in diameter and / or length.

[0035] The cannula assembly 102 also includes a blood inflow cage 107 positioned toward the end of the cannula assembly 102 opposite the blood pump housing component 103. The blood inflow cage 107 includes one or more input ports 111. The blood pump assembly 101 is configured such that actuation of the blood pump motor 110 and drive shaft 104 rotates an impeller hub 113 (which may include impeller blades not shown in FIGS. 1-3 ) to draw blood or other fluids into the blood inflow cage 107 (or blood inlet manifold) through the one or more input ports 111. Blood received through the blood inflow cage 107 travels through the cannula assembly 102 to the blood pump housing component 103. Blood entering the blood pump housing component 103 is discharged from the blood pump housing component 103 through a window in the outflow cage or a blood discharge aperture (not shown) at the proximal end of the blood pump housing component 103. In some embodiments, the direction of flow may be opposite to that of the devices illustrated herein. In such an embodiment, blood inflow occurs on the side of the cannula assembly 102 connected to the blood pump housing component 103, and blood outflow occurs on the opposite side of the cannula assembly 102. When placed inside a patient's body, the blood pump assembly 101 may pump blood from the left ventricle (via the blood inflow cage 107) to the aorta (via the blood outlet aperture). The blood pump assembly 101 includes a catheter shaft 106 extending from a blood pump motor housing 105 at a proximal end of the blood pump assembly 101. The catheter shaft 106 houses an electrical connector cable that provides power and control signals to the blood pump motor 110 and receives information from one or more sensors, such as sensor 1020; the sensors are described in further detail herein in accordance with certain embodiments. In some embodiments, the catheter shaft 106 includes one or more lumens that facilitate receiving a purging fluid and that are used as conduits for transmission fibers.In some embodiments, the interior of one or more lumens of the catheter shaft 106 is coated with a lining of polytetrafluoroethylene (PTFE), e.g., Teflon, over at least a portion of the length of the lumen or lumens. The PTFE lining has a low coefficient of friction, allowing the transmission fiber to move more freely through the lumen or lumens and to be easily inserted or retracted as needed.

[0036] The blood pump assembly 101 includes a flexible, atraumatic extension 108 (e.g., a pigtail) extending from a blood inflow cage 107 at a distal end of the blood pump assembly 101. The extension 108 includes a curved portion 109. The extension 108 helps stabilize the blood pump assembly 101 in the correct position, for example, within the left ventricle. In certain embodiments, the extension 108 is configurable from a straight configuration to a partially curved configuration. Thus, the extension 108 may be constructed, at least in part, of a flexible material.

[0037] 4-8 show various views of the sensor 1020 installed on the blood pump assembly 101 of FIG. 1. FIG. 4 is an enlarged perspective view of the sensor 1020 installed on the outflow cage 400 of the blood pump assembly 101 of FIG. 1. FIG. 5 is an enlarged side view of the sensor 1020 and outflow cage 400 of FIG. 4. FIG. 6 is an enlarged end view of the blood pump assembly 101 of FIG. 4, showing the impeller hub 113, impeller blades 140, and exemplary shielding features for protecting the sensor 1020. FIG. 7 is an enlarged end view of the sensor 1020 and shielding features of the blood pump assembly 101 of FIG. 4. FIG. 8 is a perspective view of the blood pump assembly 101 of FIG. 4, showing a cap and cover that provide a smooth transition between the outflow cage 400 and the shielding features. For clarity, the cannula assembly 102 has been omitted from FIGS. 4-8.

[0038] As shown in the figures, the blood pump assembly 101 may include a shield. The shield may include a sensor visor, a barrier bump, an additional protective layer (e.g., a silicone layer), and / or a blood aperture. For example, in Figs. 4-8, the shield includes a sensor visor 1022, a barrier bump 123, and a blood aperture 136. In Figs. 4-8, the blood pump assembly 101 further includes a plurality of struts 127, one or more output ports 125, a sensor bed 134, a transmission fiber 1024, a recess 122, an impeller blade 140, and a transmission fiber bed 135. The blood pump housing component 103 includes an outflow cage 400. The sensor 1020 includes a sensor head 721 and a sensor membrane 1023. In embodiments having both a barrier bump 123 and a sensor visor 1022, the barrier bump 123 may include a mechanism for connecting to the sensor visor 1022. 4-8, for example, the barrier bump 123 includes a visor notch 124 that receives and holds a portion of a sensor visor 1022 in a fixed position. The sensor 1020 is attached to the outflow cage 400 of the blood pump housing component 103. For example, in FIGS. 4-7, the sensor 1020 is coupled distally to one of the struts 127 of the outflow cage 400 of the blood pump housing component 103 and sits within the sensor bed 134. Preferably, the sensor 1020 is not positioned on one of the struts 127. For example, in some embodiments, the sensor 1020 is positioned on a portion of the outflow cage 400 distal to the strut 127 (e.g., 0.1 mm, 0.5 mm, 1 mm, 2 mm, 5 mm, 1 cm, or any other suitable distance distal). Alternatively, the sensor 1020 may be positioned on the blood inflow cage (eg, blood inflow cage 107) or on the cannula (eg, cannula assembly 102).

[0039] The sensor membrane 1023 of the sensor 1020 is configured to deflect in response to changes in blood parameters, such as changes in pressure, flow rate, fluid composition, and / or viscosity. The sensor membrane 1023 is preferably thin. In some embodiments, the sensor membrane 1023 is less than 2 microns thick. In some embodiments, the sensor membrane 1023 is made of a brittle glass material, such as silicon, silicon dioxide, or silicon nitride. The deflection of the sensor membrane 1023 is used to measure changes in blood parameters (e.g., blood pressure) in the blood pump assembly 101. Due to the constraint of the bend radius of the transmission fiber 1024, the sensor membrane 1023 faces toward the distal end of the blood pump assembly 101. The deflection of the sensor membrane 1023 is sensed by the sensor head 721 and transmitted to the transmission fiber 1024. The transmission fiber 1024 transmits the signal sensed by the sensor to an optical bench for signal evaluation. The transmission fiber 1024 may extend across various locations on the blood pump assembly 101 depending on the location of the sensor 1020 relative to other components of the blood pump assembly 101. In FIG. 4, the transmission fiber 1024 extends along one of the struts 127 of the blood pump housing component 103, along the blood pump motor housing 105, and through the catheter shaft 106 (not shown). In some embodiments, the transmission fiber 1024 is coated with a protective coating, such as a polymer (e.g., polyimide). The transmission fiber 1024 is attached to the blood pump housing component 103. For example, in FIG. 4, the transmission fiber 1024 is positioned within the transmission fiber bed 135, which is a recess in the outflow cage 400 of the blood pump housing component 103. The measured blood parameters (e.g., pressure) and changes in such parameters provide information regarding the operation of the blood pump assembly 101, the position of the blood pump assembly 101 (e.g., in pressure sensor embodiments, pressure differences relate to various locations within the heart), and the patient's vital signs in response to the placement and operation of the blood pump assembly 101.

[0040] In embodiments with sensors that optically transmit sensed signals, the transmission fiber 1024 is an optical fiber, and the transmission fiber 1024 extends to a light source. In such embodiments, the light reflection or resonant frequency (e.g., in embodiments using the Fabry-Perot resonator sensing principle) in the sensor head 721 changes in response to a change in the position of the sensor membrane 1023 under deflection in response to a change in blood parameter. The change in light reflection or resonant frequency is transmitted by the transmission fiber 1024 from the sensor head 721 to an optical bench (or other suitable component configured to convert the light modulated pressure signal into electronically calibrated or digital data that can be stored and / or analyzed using software) for signal evaluation. The optical bench may be remote from the blood pump housing component 103, for example, located in a console or connector outside the body. In embodiments with sensors that sense pressure, the movement of the sensor membrane 1023 in response to pressure changes on its surface is transmitted by the transmission fiber 1024 to an optical bench or transducer for pressure determination. As mentioned above, the sensor may transmit the sensed pressure signal optically.

[0041] The barrier bump 123 is positioned on the anterior / distal side of the sensor membrane 1023 to protect the sensor membrane 1023. The barrier bump 123 protrudes from the outflow cage 400 of the blood pump housing component 103. In some embodiments, the barrier bump 123 is constructed of the same material as the blood pump housing component 103, such as stainless steel. The barrier bump 123 may be electropolished, mechanically polished, or otherwise treated in a manner to provide a smooth surface that minimizes thrombus and blood flow shear stress. In particular, it is preferred that all surfaces of the barrier bump 123 that contact the blood are smooth to minimize thrombus and blood flow shear stress. The sensor 1020 may include various other protective features. In embodiments having both a barrier bump 123 and a sensor visor 1022, such as those shown in Figures 4-8, the barrier bump 123 may include a visor notch 124 configured to receive and hold the sensor visor 1022 in a fixed position. Other mechanisms for connecting the sensor visor 1022 to the barrier bump 123 may be utilized, such as adhesives (e.g., epoxies), welding, etc.

[0042] As shown in the figures, the sensor visor 1022 may be a shroud that extends over the sensor membrane 1023. In embodiments having both a barrier bump 123 and a sensor visor 1022, such as those shown in Figures 4-8, the sensor visor 1022 may extend to the visor notch 124 of the barrier bump 123. The sensor visor 1022 helps direct or deflect blood flow through the blood aperture 136 and out of the blood pump housing component 103. The sensor visor 1022 deflects blood toward the sensor membrane 1023 of the sensor 1020 and out laterally through the recess 122. In some embodiments, the sensor visor 1022 is constructed of stainless steel. The sensor visor 1022 may have a curved geometry. The sensor visor 1022 preferably has a smooth surface for some or all of the surfaces that come into contact with blood to prevent blood clots. The sensor visor 1022 may be at least partially constructed of a biocompatible material and / or have a coating of a biocompatible material.

[0043] As described herein, the blood pump assembly 101 may be percutaneously introduced through the vasculature during a cardiac procedure. For example, the blood pump assembly 101 may be inserted by a catheter procedure through the femoral artery into the ascending aorta and past the aortic valve into the left ventricle to provide support to the left side of the heart. As previously described, introducing the blood pump assembly 101 through the introducer unit into the vasculature may include navigating tortuous directional changes and calcified anatomical structures in the vasculature. The sensor 1020, and particularly the sensor membrane 1023, may be composed of delicate or brittle components that may be easily damaged by the tortuous and calcified anatomical structures of the vasculature. The barrier bump 123 and the sensor visor 1022 allow the sensor 1020 to navigate the tortuous and calcified anatomical structures of the vasculature and remain operable. For example, the barrier bump 123 may protect the sensor membrane 1023 by deflecting oncoming obstacles caused by calcification in the vasculature or a change in orientation of the sensor 1020. As another example, the sensor visor 1022 may protect the sensor membrane 1023 by preventing soft obstacles, such as valve leaflets on a blood pump introducer, from contacting and damaging the sensor membrane 1023. In embodiments having both a barrier bump 123 and a sensor visor 1022, such as those shown in FIGS. 4-8, obstacles deflected by the barrier bump 123 may ride on the sensor visor 1022, thereby preventing the obstacle from contacting and / or damaging the sensor membrane 1023.

[0044] The sensor membrane 1023 is positioned within the recess 122 and is positioned adjacent to the blood aperture 136. The recess 122 is where blood flowing from the cannula assembly 102 is directed to the sensor membrane 1023 and interacts directly or indirectly with the sensor membrane 1023 so that fluid pressure can be determined. In FIGS. 4-8, blood may interact directly with the sensor membrane 1023. In embodiments where one or more protective layers are attached to the sensor membrane 1023 (as described below in connection with FIGS. 11-12), blood interacts indirectly with the sensor membrane 1023. The recess 122 is configured to be wider than the sensor 1020 so that blood can easily exit the sensor 1020, e.g., laterally, thereby allowing pressure equalization with the pressure against the outside of the outflow cage 400 of the blood pump housing component 103. In some embodiments, the width of the recess 122 is configured to be approximately equal to or less than the width of the sensor 1020.

[0045] The blood aperture 136 allows blood to flow toward the sensor membrane 1023 and then exit the blood pump housing component 103. In the illustrated embodiment, the blood aperture 136 is positioned distal to the sensor membrane 1023, and the blood aperture 136 is in the recess 122. To prevent blood from accumulating or clotting on the surface of the sensor membrane 1023, the blood aperture 136 allows blood flowing through the cannula assembly 102 to wash the front end of the sensor membrane 1023. As shown, the blood aperture 136 extends from the interior of the blood pump housing component 103 into the recess 122. The blood aperture 136 also allows blood that enters the blood pump housing component 103 from the cannula assembly 102 to exit the blood pump housing component 103 in a manner similar to the way blood exits the blood pump housing component 103 through one or more output ports 125. Blood exiting the blood pump housing component 103 through the blood aperture 136 flows past the sensor membrane 1023 in the recess 122. The blood aperture 136 may be about 250 microns in diameter. In some embodiments, the diameter of the blood aperture 136 is greater than 250 microns, such as, for example, 275 microns, 300 microns, 325 microns, 350 microns, greater than 350 microns, or any suitable diameter. In other embodiments, the diameter of the blood aperture 136 is less than 250 microns, such as, for example, 225 microns, 200 microns, 175 microns, 150 microns, 125 microns, 100 microns, less than 100 microns, or any suitable diameter. In some embodiments, the flow may be directed inward. In certain embodiments, the flow may be bidirectional, with blood flowing in and out of the blood aperture 136 while washing the sensor membrane 1023. Blood aperture 136 preferably has a smooth surface for some or all of the surfaces that come into contact with blood to prevent blood clots. In embodiments where sensor 1020 and sensor membrane 1023 are positioned distal to the positions shown in Figures 4-8, the likelihood of blood clotting increases and blood aperture 136 becomes more critical.In other embodiments where the sensor 1020 and sensor membrane 1023 are positioned more proximally than shown in Figures 4-8, the blood aperture 136 may not be necessary and instead the sensor membrane 1023 may be directly open to the blood.

[0046] The sensor 1020 may be attached to the outflow cage 400 of the blood pump housing component 103 (or other components of the blood pump assembly 101, such as the inflow cage 107) in a variety of ways. In FIG. 4, the sensor 1020 sits in a sensor bed 134 configured to receive the sensor 1020 in a recessed position of the outflow cage 400 of the blood pump housing component 103. The sensor bed 134 extends directly into the recess 122 to provide and facilitate an interface between the sensor membrane 1023 and blood entering the recess 122 through the blood aperture 136. In some embodiments, the sensor bed 134 includes a laser texturing strip to facilitate placement and retention of the sensor 1020 therein. In certain embodiments, the sensor bed 134 includes potting and / or smoothing by using epoxy or silicone for smooth structures in and / or around the sensor bed 134.

[0047] As shown in FIG. 5, an opening / window 1025 allows blood exiting or entering the blood aperture 136 (shown in FIG. 4) to wash the sensor membrane 1023. The barrier bump 123 is constructed to have a height greater than the height of the sensor 1020 (e.g., height in a direction radially outward from a central longitudinal axis extending through the blood pump assembly 101) to raise the position of any obstacles encountered during insertion of the sensor 1020. This allows obstacles to be raised above and away from the sensor 1020, and in particular above the sensor membrane 1023. For example, an obstacle may pass along and over the sensor visor 1022 without contacting the sensor membrane 1023. The sensor 1020 is recessed within the outflow cage 400 of the blood pump housing component 103, distal to one of the struts 127. Positioning the sensor 1020 distal to the location shown in Figure 5 on the blood pump housing component 103 may aid in repositioning the blood pump assembly 101. In some embodiments, the sensor 1020 and / or sensor visor 1022 may be coupled to the outflow cage 400 of the blood pump housing component 103 (or another component of the blood pump assembly 101, such as the inflow cage 107) and the barrier bump 123 with an adhesive, including but not limited to an epoxy resin, welded, or coupled together using other fastening techniques known to those skilled in the art.

[0048] The blood pump housing component 103 may house a drive shaft 104, which may be axially coupled to the blood pump motor 110. The drive shaft 104 is coupled to an impeller hub 113 at a distal end portion of the drive shaft 104. The impeller hub 103 is coupled to impeller blades 140. The impeller blades 140 draw blood through the cannula assembly 102 to create a highly viscous spiral flow of blood that exits the blood pump housing component 103 through a number of blood drainage windows 125 in the sidewall of an outflow cage 400 of the blood pump housing component 103. In some embodiments, the drainage windows are formed in the wall of the cannula assembly 102 instead of or in addition to being formed in the blood pump housing component 103. The impeller blades 140 may be expandable or compressible. The outflow cage 400 includes a number of struts 127 positioned around the periphery of the outflow cage 400. The plurality of struts 127 separate the one or more output ports 125. At least one of the plurality of struts 127 includes a transmission fiber bed 135 for the transmission fiber 1024 and aligns with a sensor bed 134 and a transmission fiber bed 135 (shown in FIG. 4 ) for housing the sensor 1020 and the transmission fiber 1024, respectively.

[0049] In some embodiments, the blood pump assembly 101 includes features that provide a smooth transition over the particular structure of the blood pump assembly 101. As shown in FIG. 8, when the sensor visor 1022 is properly positioned, a cap 1027 covers the visor notch 124 (not visible in the figure). The cap 1027 may include an adhesive, epoxy, weld, or other structure or material that can hold the sensor visor 1022 in place and / or provide a smooth transition across the barrier bump 123. Similarly, the sensor 1020 and / or the transmission fiber 1024 (not visible in the figure) are coupled to the outflow cage 400 of the blood pump housing component 103 through a cover 1028; the cover 1028 may include, without limitation, an epoxy layer that provides a smooth transition over the sensor 1020 and secures the sensor 1020 and the transmission fiber 1024 in place. Those skilled in the art will appreciate that various other features that provide a smooth transition over the particular structure of the blood pump assembly 101 are possible. Preferably, all blood-contacting surfaces of the blood pump assembly 101 are smooth to minimize thrombus and blood flow shear stress.

[0050] 9 is a side view of a sensing assembly 1900 for a catheter-based blood pump assembly. The sensing assembly 1900 includes a sensor 1920, a sensor visor 1922, a transmission fiber 1924, and a connector 1925. The sensor 1920 includes a sensor head 1921 and a sensor membrane 1923. The sensor head 1921 houses the sensing components. The sensor visor 1922 may be constructed of a material including, but not limited to, stainless steel. The transmission fiber 1924 extends from the connector 1925 to the sensor head 1921. In an embodiment in which the sensing assembly 1900 senses pressure and optically transmits the sensed signal, the transmission fiber 1924 optically couples the sensor head 1921 through the connector 1925 to a light source configured to send light to the sensor membrane 1923 and send a modulated signal back to the optical bench / transducer. When pressure is applied to the sensor membrane 1923 under high pressure and / or vacuum caused by the rotating impeller blades (not shown), the sensor membrane 1923 deflects, causing a change / modulation in the reflected light that is sent back from the sensor head 1921. The change in light is detected by an optical bench / transducer to determine the pressure change.

[0051] FIG. 10 is a partial cross-sectional side view of a sensing assembly 2000 for a catheter-type blood pump assembly. The sensing assembly 2000 includes a sensor 2020, a transmission fiber 2024, a jacket 2027, a glue 2028, and a sensor visor 2022. The sensor 2020 includes a sensor head 2021, a sensor membrane 2023, and a temperature compensation portion 2042. The sensor head 2021 includes a cavity 2040. The transmission fiber 2024 terminates at a proximal portion of the sensor head 2021 and is coupled to the sensor head 2021 with low loss. The cavity 2040 in combination with the sensor membrane 2023 forms a Fabry-Perot resonator. To enable the resonant measurement principle, both sides of the cavity 2040 are fabricated to be optically reflective. Partial reflection is realized on one side, preferably the side of the transmission fiber 2024, and total reflection is realized preferably on the side of the sensor membrane 2023, in terms of what is needed to enable detection of the signal. The temperature compensation portion 2042 is configured to prevent drift of the sensed signal due to temperature fluctuations. The temperature compensation portion 2042 is smaller in size than the sensor membrane 2023 and may comprise silicon dioxide. The jacket 2027 is positioned around the transmission fiber 2024 and may comprise a glass ring. The transmission fiber 2024 is coupled to the sensor head 2021 by glue 2028, which may be a UV-curable epoxy resin. The sensor visor 2022 is configured to extend beyond the distal end of the sensor membrane 2023.

[0052] The shield for the blood pump assembly 101 may be configured in other ways. In Figs. 11-12, the shield includes an additional protective layer covering the sensor membrane. Fig. 11 is a partial cross-sectional side view of another sensing assembly 1100 including an additional protective layer covering the sensor membrane. As shown, the sensing assembly 1100 includes a sensor 1120, a transmission fiber 1124, a jacket 1127, a glue 1128, a sensor visor 1122, and a lamina 1102. The sensor 1120 includes a sensor head 1121, a sensor membrane 1123, and a temperature compensation portion 1142. The sensor head 1121 includes a cavity 1140. The transmission fiber 1124 terminates at a proximal portion of the sensor head 1121 and is coupled to the sensor head 1121 with low loss. The cavity 1140 in combination with the sensor membrane 1123 forms a Fabry-Perot resonator. To enable the resonant measurement principle, both sides of the cavity 1140 are manufactured to reflect light. At one side, preferably the side of the transmission fiber 1124, partial reflection is realized in terms of what is needed to enable detection of the signal, and at the side of the sensor membrane 1123, total reflection is realized. The temperature compensation portion 1142 is configured to prevent drift of the sensed signal due to temperature fluctuations. The temperature compensation portion 1142 is smaller in size than the sensor membrane 1123 and may comprise silicon dioxide. The jacket 1127 is positioned around the transmission fiber 1124 and may comprise a glass ring. The transmission fiber 1124 is connected to the sensor head 1121 by a glue 1128, which may be a UV-curable epoxy resin. The sensor visor 1122 is configured to extend beyond the distal end of the sensor membrane 1123. The thin layer 1102 is placed over and covers the sensor membrane 1123, protecting it from damage due to blood flow over the sensor membrane 1123. For example, the thin layer 1102 may prevent dissolution of the sensor membrane 1123 due to chemical reactions with the patient's blood. In addition, the thin layer 1102 prevents biological fouling from forming directly on the sensor membrane 1123.

[0053] The thin layer 1102 may comprise a material that can be applied and cured onto the sensor membrane 1123 as a gel. For example, the thin layer 1102 may comprise silicone. In some embodiments, the thin layer 1102 comprises silicon oxide, oxide, metal, metal oxide (such as tantalum pentoxide (Ta2O5), titanium, or titanium oxide), or any other coating commonly used in microelectromechanical systems (MEMS) or semiconductor processing. The thin layer 1102 may have a thickness of about 1 micron. In some embodiments, the thin layer 1102 has a thickness greater than 1 micron. For example, the thin layer 1102 may have a thickness of 2 microns, 3 microns, 4 microns, 5 microns, more than 5 microns, or any suitable thickness. In certain embodiments, the thin layer 1102 has a thickness less than 1 micron. For example, the thin layer 1102 may have a thickness of 0.8 microns, 0.6 microns, 0.4 microns, 0.2 microns, less than 0.2 microns, or any suitable thickness. In certain embodiments, the protective layer may be multiple layers that function as different protective barriers. For example, one layer may be a very thin layer of metal oxide (such as tantalum pentoxide (Ta2O5), titanium, or titanium oxide), silicon oxide, oxide, metal, or any other coating commonly used in MEMS or semiconductor processing, and another layer may be an additional polymer protective layer, such as a layer of silicone polymer. The very thin layer of metal / metal oxide may be, for example, about 20 nanometers thick. In other embodiments, three or more layers may be preferred to enhance adhesion between different layers (i.e., silicon, metal, polymer) and provide the desired protective capabilities. Depending on the stiffness or drift behavior of the material, different thicknesses may be considered. For materials with stronger negative effects on the signal (e.g., damping, drift, nonlinearity), a thin layer would be preferred. For softer protective layers, a thicker layer may be preferred to enhance the protective function.

[0054] 12 is a partial cross-sectional side view of another sensing assembly 1200 including an additional protective layer covering the sensor membrane. The sensing assembly 1200 includes a sensor 1220, a transmission fiber 1224, a jacket 1227, a glue 1228, a sensor visor 1222, and a layer 1202. The sensor 1220 includes a sensor head 1221, a sensor membrane 1223, and a temperature compensation portion 1242. The sensor head 1221 includes a cavity 1240. The transmission fiber 1224 terminates at a proximal portion of the sensor head 1221 and is coupled to the sensor head 1221 with low loss. The cavity 1240 in combination with the sensor membrane 1223 forms a Fabry-Perot resonator. To enable the resonant measurement principle, both sides of the cavity 1240 are fabricated to be optically reflective. Partial reflection is realized on one side, preferably the side of the transmission fiber 1224, and total reflection is realized preferably on the side of the sensor membrane 1223, in terms of what is needed to enable detection of the signal. The temperature compensation portion 1242 is configured to prevent drift of the sensed signal due to temperature fluctuations. The temperature compensation portion 1242 is smaller in size than the sensor membrane 1223 and may include silicon dioxide. The jacket 1227 is positioned around the transmission fiber 1224 and may include a glass ring. The transmission fiber 1224 is coupled to the sensor head 1221 by glue 1228, which may be a UV-curable epoxy resin. The sensor visor 1222 is configured to extend beyond the distal end of the sensor membrane 1223.

[0055] The layer 1202 overlays and covers the sensor membrane 1223 to protect the sensor membrane 1223 from damage due to blood flow over the sensor membrane 1223. For example, the layer 1202 may prevent the sensor membrane 1223 from dissolving due to a chemical reaction with the patient's blood. Additionally, the layer 1202 prevents biological fouling from forming directly on the sensor membrane 1223. In embodiments where the sensing assembly 1200 is a pressure sensor, the layer 1202 transmits pressure from the blood to the sensor membrane 1223 so that blood pressure can be sensed. The layer 1202 may include a material that is adherent and curable onto the sensor membrane 1223 as a gel. For example, the thin layer 1202 may include silicone. The layer 1202 may have a thickness of about 0.13 mm. In some embodiments, the layer 1202 has a thickness of about 0.13 mm or greater. For example, layer 1202 may have a thickness of 0.14 mm, 0.15 mm, 0.16 mm, 0.17 mm, 0.18 mm, 0.19 mm, 0.2 mm, more than 0.2 mm, or any suitable thickness. In certain embodiments, layer 1202 has a thickness of about 0.13 mm or less. For example, layer 1202 may have a thickness of 0.12 mm, 0.11 mm, 0.1 mm, 0.09 mm, 0.08 mm, 0.07 mm, 0.06 mm, 0.05 mm, less than 0.05 mm, or any suitable thickness. Sensor membrane 1223 is recessed further proximally relative to sensor visor 1222 than sensor membrane 1123 in the embodiment of FIG. 11 by a distance approximately equal to the thickness of layer 1202. By recessing sensor membrane 1223 further under sensor visor 1222, protection against damage from blood flow on sensor membrane 1223 can be improved. The sensing assembly 1200 may include any number of additional protective layers deposited on the sensor membrane 1223, such as, for example, one, two, or three protective layers.

[0056] The sensing assembly 1200 may also include a gel (e.g., silicone gel) or other material proximal to the sensor membrane 1223, which may partially or completely fill the cavity 1240 to prevent blood ingress. This may prevent clot formation in this area of ​​the sensing assembly 1200 and may also prevent damage to the sensing assembly 1200, as blood may damage the transmission fiber 1224 and prevent connection between the transmission fiber 1224 and the sensor head 1221.

[0057] FIG. 13 is a flow diagram of an exemplary process 1300 for manufacturing a blood pump assembly. In step 1302, a sensor (e.g., sensor 1020 in FIG. 4) is coupled to a blood pump housing component (e.g., outflow cage 400 of blood pump housing component 103 in FIG. 4), such as by using an epoxy resin. Coupling the sensor to the outflow cage of the blood pump housing component may include positioning the sensor in a recess (e.g., recess 122 in FIG. 4) of the blood pump housing component. Alternatively and as previously described, the sensor may be coupled to a cannula assembly of the blood pump assembly. The sensor includes a sensor membrane (e.g., sensor membrane 1023 in FIG. 4) configured to deflect in response to a change in a blood parameter, such as a change in pressure, flow rate, fluid composition, or viscosity. The sensor membrane is coupled to a transmission fiber (e.g., transmission fiber 1024 in FIG. 4). The sensor includes a sensor visor (e.g., sensor visor 1022 in FIG. 4) extending over the sensor membrane. To protect the sensor membrane from damage due to blood flow on the sensor membrane, one or more protective layers (e.g., thin layer 1102 in FIG. 11) may be applied on the sensor membrane. For example, the protective layer may prevent the sensor membrane from dissolving due to chemical reaction with the patient's blood. In addition, the protective layer may prevent biological fouling from forming directly on the sensor membrane. Alternatively, the protective layer may be thicker than the thin layer 1102 in FIG. 11 (e.g., layer 1202 in FIG. 12), and the sensor membrane may be recessed further under the sensor visor by a distance approximately equal to the thickness of that layer. By recessing the sensor membrane further under the sensor visor, protection against damage due to blood flow on the sensor membrane may be improved.

[0058] In step 1303, an impeller hub and blades (e.g., impeller hub 113 and impeller blades 140 of FIG. 6) are coupled to a drive shaft (e.g., drive shaft 104 of FIG. 8) such that the impeller hub and impeller blades rotate as the drive shaft rotates. Alternatively, the impeller hub, blades, and drive shaft may be monolithic and integrally formed. The outflow cage of the blood pump housing component may include one or more output ports (e.g., output port 125 of FIG. 5) and a number of struts (e.g., strut 127 of FIG. 5) extending between the one or more output ports. The recess may be located distal to one of the struts in the outflow cage of the blood pump housing component.

[0059] In step 1304, a cannula assembly (e.g., cannula assembly 102 in FIG. 1) is coupled to a blood pump housing component. In step 1306, a sensor visor is positioned in a visor notch of a barrier bump (e.g., visor notch 124 of barrier bump 123 in FIG. 4) protruding from an outflow cage of the blood pump housing component. The barrier bump and sensor visor provide an advantage to the sensor in terms of allowing it to navigate the tortuous and calcified anatomy of the vasculature and remain operable. In step 1310, a blood inflow cage (e.g., blood inflow cage 107 in FIG. 1) is coupled to the cannula assembly. In step 1312, a flexible atraumatic extension (e.g., flexible atraumatic extension 108 in FIG. 1) is coupled to the blood inflow cage.

[0060] 14 is a flow diagram of an exemplary process 1400 for detecting blood pressure. In step 1402, blood is pumped through a cannula assembly (e.g., cannula assembly 102 in FIG. 1) using impeller blades (e.g., impeller blades 140 in FIG. 6) positioned at least partially within a blood pump housing component (e.g., blood pump housing component 103 in FIG. 1). The impeller blades are coupled to an impeller hub (e.g., impeller hub 113 in FIG. 6) that is rotated by a drive shaft coupled to the impeller hub. The blood pump housing component includes an outflow cage (e.g., outflow cage 400 in FIG. 4), and pumping the blood may include pumping the blood through one or more output ports (e.g., output port 125 in FIG. 4) in the blood pump housing component.

[0061] In step 1403, the blood pressure of the pumped blood is detected using an optical pressure sensor (e.g., sensor 1020 in FIG. 4) coupled to the outflow cage of the blood pump housing component. The optical pressure sensor includes a sensor membrane (e.g., sensor membrane 1023 in FIG. 4) configured to deflect in response to pressure changes on the sensor membrane. The sensor membrane may include a glass / silicon material. The sensor membrane may face toward the distal end of the blood pump assembly. The sensor membrane may have a thickness as described above. The optical pressure sensor includes a sensor visor (e.g., sensor visor 1022 in FIG. 4) that extends distally a distance beyond the sensor membrane to form an overhanging shroud portion over the sensor membrane. The outflow cage of the blood pump housing component may include a barrier bump (e.g., barrier bump 123 in FIG. 4) protruding from the outflow cage of the blood pump housing component. The barrier bump and sensor visor provide advantages to the optical pressure sensor in terms of allowing it to navigate the tortuous and calcified anatomical structures of the vasculature and remain operable. The barrier bump may protect the sensor membrane by deflecting oncoming obstacles caused by calcification in the vasculature or changes in sensor orientation. The sensor visor may protect the sensor membrane by preventing soft obstacles, such as valve leaflets on a blood pump introducer, from contacting and damaging the sensor membrane. An obstacle deflected by the barrier bump may ride on the sensor visor, thereby preventing the obstacle from contacting and / or damaging the sensor membrane. The barrier bump may be positioned in front of a recess (e.g., recess 122 in FIG. 4). The recess may be between the barrier bump and the sensor membrane.

[0062] To protect the sensor membrane from damage due to blood flow on the sensor membrane, one or more protective layers (e.g., thin layer 1102 in FIG. 11) may be applied on the sensor membrane. For example, the layer may prevent the sensor membrane from dissolving due to chemical or biological reaction with the patient's blood. In addition, the layer may prevent biological fouling from forming directly on the sensor membrane. Alternatively, the protective layer may be thicker than the thin layer 1102 in FIG. 11 (e.g., layer 1202 in FIG. 12), and the sensor membrane may be further recessed under the sensor visor by a distance approximately equal to the thickness of the layer. Recessing the sensor membrane under the sensor visor may improve protection against damage due to blood flow on the sensor membrane. In the case of an optical sensor, the sensor is directly or indirectly coupled to an optical fiber (e.g., transmission fiber 1024 in FIG. 4).

[0063] In step 1404, the sensor membrane is washed by blood flowing through a blood aperture (e.g., blood aperture 136 in FIG. 4) that extends through the outflow cage of the blood pump housing component. Washing the sensor membrane prevents blood from accumulating or clotting on the surface of the sensor membrane.

[0064] In step 1406, blood flowing through the blood aperture is deflected using a sensor visor that may extend from the optical pressure sensor onto the sensor membrane and into a visor notch in the barrier bump. Blood may also flow out through the blood aperture and new volume of blood may flow into the blood aperture.

[0065] Additional aspects include the following:

[0066] A1. In a first additional embodiment, a blood pump assembly includes a blood pump housing component; at least one input port and at least one outlet port; and a sensor coupled to the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter, the sensor coupled to a transmission fiber, and includes a shield covering at least a portion of the sensor membrane to protect the sensor from physical damage.

[0067] A2. The blood pump assembly of A1, wherein the shield includes a barrier bump positioned distal to the sensor membrane.

[0068] A3. The blood pump assembly of A2, further comprising a sensor visor for protecting the sensor from physical damage, the sensor visor extending distally beyond the sensor membrane.

[0069] A4. The blood pump assembly of A3, wherein the sensor visor extends into a visor notch formed in the barrier bump.

[0070] A5. The blood pump assembly of A4, further comprising a cap covering the visor notch.

[0071] A6. Any of the blood pump assemblies A3-A5, wherein the sensor visor is attached to the barrier bump by adhesive or welding.

[0072] A7. The blood pump assembly of any of A1-A6, wherein the shield includes at least one protective layer covering a surface of the sensor membrane.

[0073] A8. The blood pump assembly of any of A3 to A7, wherein the sensor membrane is recessed proximally relative to the sensor visor.

[0074] A9. The blood pump assembly of any of A1-A8, wherein the shield includes a blood aperture extending through the blood pump housing component and positioned distal to the sensor membrane for flushing the sensor membrane with blood.

[0075] A10. In a second additional embodiment, a blood pump assembly includes a blood pump housing component; a cannula assembly coupled to the blood pump housing component; and a sensor coupled to the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter, the sensor coupled to a transmission fiber, and includes a passive protection mechanism to protect the sensor from damage when the blood pump assembly is inserted into a patient.

[0076] A11. The blood pump assembly of A10, wherein the passive protection mechanism includes a barrier positioned distal to the sensor membrane.

[0077] A12. The blood pump assembly of A11, wherein the barrier protrudes from the blood pump housing component.

[0078] A13. The blood pump assembly of any of A11-A12, wherein the barrier is constructed from the same material as the blood pump housing components.

[0079] A14. The blood pump assembly of any of A11 to A13, wherein the barrier has a smooth outer surface that contacts the blood.

[0080] A15. The blood pump assembly of any of A11-A14, wherein the barrier has a radial height approximately equal to or greater than the radial height of the sensor.

[0081] A16. The blood pump assembly of any of A10-A15, further comprising one or more protective layers deposited on a surface of the sensor membrane facing toward the distal end of the blood pump assembly.

[0082] A17. The blood pump assembly of A16, wherein the one or more protective layers include a single layer, the single layer being deposited on the sensor membrane and formed of a material that is depositable and hardenable as a gel.

[0083] A18. A blood pump assembly of A16 or A17, wherein the one or more protective layers include a material capable of preventing dissolution of the sensor membrane by chemical or biological reaction with blood.

[0084] A19. A blood pump assembly of any of A16 to A18, wherein the one or more protective layers include a layer of silicone.

[0085] A20. A blood pump assembly according to any of A16 to A19, wherein one or more protective layers comprise a metal oxide.

[0086] A21. The blood pump assembly of any of A10 to A20, wherein the sensor membrane has a thickness of 2 microns or less.

[0087] A22. The blood pump assembly of any of A10-A21, wherein the sensor is positioned within a sensor bed within the blood pump housing component.

[0088] A23. The blood pump assembly of any of A10 to A22, wherein the sensor is an optical sensor that transmits an optical signal.

[0089] A24. The blood pump assembly of any of A10-A23, wherein the blood pump housing component has a substantially cylindrical and elongated shape.

[0090] In a third additional embodiment, a blood pump assembly includes a drive unit, an impeller blade rotatably coupled to the drive unit, a blood pump housing component including a circumferential wall extending about an axis of rotation of the impeller blade, a cannula assembly coupled to the blood pump housing component, and a sensor coupled to the circumferential wall of the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter and coupled to a transmission fiber, the sensor including a shield covering at least a portion of the sensor membrane.

[0091] B2. The blood pump assembly of B1, wherein the shield includes a barrier bump positioned distal to the sensor membrane and a sensor visor overhanging the sensor membrane.

[0092] B3. Blood pump assembly of B2 with the sensor visor extending to the barrier bump.

[0093] B4. The blood pump assembly of B3, with the sensor visor extending into the visor notch of the barrier bump.

[0094] B5. Blood pump assembly from B4, with the cap covering the visor notch.

[0095] B6. A blood pump assembly of any of B2-B5, wherein the sensor visor is attached to the barrier bump by an adhesive.

[0096] B7. The blood pump assembly of any of B2-B6, wherein the shield includes a protective layer covering a surface of the sensor membrane.

[0097] B8. The blood pump assembly of B7, wherein the sensor membrane is further recessed beneath the sensor visor by a distance approximately equal to the thickness of the protective layer.

[0098] B9. The blood pump assembly of any of B2-B8, wherein the shield includes a blood aperture extending through the peripheral wall of the blood pump housing component and positioned distal to the sensor membrane for washing the sensor membrane.

[0099] B10. The blood pump assembly of B9, wherein the blood aperture is positioned between the sensor membrane and the barrier bump.

[0100] B11. The blood pump assembly of any of B9-B10, wherein the sensor visor extends over the blood aperture.

[0101] In a fourth additional embodiment, a blood pump assembly includes a drive unit, an impeller blade rotatably coupled to the drive unit, a blood pump housing component including a circumferential wall extending about an axis of rotation of the impeller blade, a cannula assembly coupled to the blood pump housing component, and a sensor coupled to the circumferential wall of the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter and coupled to a transmission fiber, the sensor including a shield configured as a passive protection mechanism positioned distal to the sensor membrane.

[0102] B13. The blood pump assembly of B12, wherein the passive protection mechanism positioned distal to the sensor membrane includes a barrier positioned distal to the sensor membrane.

[0103] B14. The blood pump assembly of B13, wherein the barrier positioned distal to the sensor membrane includes a barrier bump positioned distal to the sensor membrane.

[0104] B15. The blood pump assembly of B14, wherein the barrier bump protrudes from the peripheral wall of the blood pump housing component.

[0105] B16. The blood pump assembly of any of B14-B15, wherein the barrier bump is constructed from the same material as the blood pump housing components.

[0106] B17. The blood pump assembly of any of B14-B16, wherein the barrier bump has a smooth surface.

[0107] B18. Any of the blood pump assemblies B14-B17, wherein the barrier bump is constructed of stainless steel.

[0108] B19. The blood pump assembly of any of B14-B18, wherein the barrier bump is electropolished or mechanically polished.

[0109] B20. The blood pump assembly of any of B14-B19, wherein the barrier bump has a height approximately equal to or greater than the height of the sensor.

[0110] B21. The blood pump assembly of any of B14-B20, wherein the barrier bump has a visor notch configured to receive a sensor visor overhanging the sensor membrane.

[0111] B22. The blood pump assembly of any of B14-B21, wherein the shield includes a passive protection mechanism positioned such that the sensor membrane is positioned between the passive protection mechanism and a peripheral wall of the blood pump housing component.

[0112] B23. The blood pump assembly of B22, wherein the passive protection mechanism includes a barrier positioned such that the sensor membrane is positioned between the passive protection mechanism and a peripheral wall of the blood pump housing component, the barrier positioned such that the sensor membrane is between the barrier and the peripheral wall of the blood pump housing component.

[0113] B24. The blood pump assembly of B23, including a sensor visor overhanging the sensor membrane, the barrier positioned such that the sensor membrane is between the barrier and a peripheral wall of the blood pump housing component.

[0114] B25. Blood pump assembly as in B24, with the sensor visor being stainless steel.

[0115] B26. The blood pump assembly of B24-B25, wherein the sensor visor has a smooth surface.

[0116] B27. The blood pump assembly of B24-B26, wherein the sensor comprises a biocompatible material.

[0117] B28. The blood pump assembly of B24-B27, where the sensor visor is coated with a biocompatible material.

[0118] B29. In a fifth additional embodiment, a blood pump assembly includes a drive unit, an impeller blade rotatably coupled to the drive unit, a blood pump housing component including a circumferential wall extending about an axis of rotation of the impeller blade, a cannula assembly coupled to the blood pump housing component, and a sensor coupled to the circumferential wall of the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter and coupled to a transmission fiber, the sensor including a shield configured as a passive protection mechanism covering a surface of the sensor membrane.

[0119] B30. The blood pump assembly of B29, wherein the passive protection mechanism covering the surface of the sensor membrane includes a barrier covering the surface of the sensor membrane.

[0120] B31. The blood pump assembly of B30, wherein the barrier covering the surface of the sensor membrane includes a protective layer deposited on the surface of the sensor membrane.

[0121] B32. The blood pump assembly of B31, wherein the sensor membrane faces toward a distal end of the blood pump assembly, and the protective layer deposited on a surface of the sensor membrane is deposited on a surface of the sensor membrane that faces toward the distal end of the blood pump assembly.

[0122] B33. The blood pump assembly of any of B31-B32, wherein the protective layer has a thickness approximately equal to or greater than 0.03 mm.

[0123] B34. The blood pump assembly of any of claims B31-B32, wherein the protective layer has a thickness approximately equal to or greater than 0.13 mm.

[0124] B35. The blood pump assembly of any of B31-B34, wherein the protective layer comprises a material that is adherent as a gel and that is hardenable.

[0125] B36. The blood pump assembly of any of B31 to B35, wherein the protective layer includes a material capable of preventing the sensor membrane from dissolving due to a chemical reaction with blood.

[0126] B37. The blood pump assembly of any of B31-B34, wherein the protective layer comprises silicone.

[0127] B38. In a sixth additional aspect, a blood pump assembly includes a drive unit, an impeller blade rotatably coupled to the drive unit, a blood pump housing component including a circumferential wall extending about an axis of rotation of the impeller blade, a cannula assembly coupled to the blood pump housing component, and a sensor coupled to the circumferential wall of the blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter and coupled to a transmission fiber, the sensor including a shield configured as one or more active protection mechanisms for the sensor membrane.

[0128] B39. The blood pump assembly of B38, wherein the one or more active protection mechanisms include a mechanism for cleaning the sensor membrane.

[0129] B40. The blood pump assembly of B39, wherein the mechanism for washing the sensor membrane includes a mechanism for washing the sensor membrane with blood.

[0130] B41. The blood pump assembly of any of B39-B40, wherein the mechanism for washing the sensor membrane includes a blood aperture extending through a peripheral wall of the blood pump housing component and positioned distal to the sensor membrane.

[0131] B42. The blood pump assembly of B41, wherein the peripheral wall of the blood pump housing component includes a recess positioned distally relative to the sensor membrane.

[0132] B43. The blood pump assembly of B42, where the recess is wider than the sensor.

[0133] B44. The blood pump assembly of B43, with the blood aperture positioned within the recess.

[0134] B45. The blood pump assembly of any of B41-B44, wherein the blood aperture allows blood entering the blood pump housing component through the cannula assembly to exit the blood pump housing component to wash the sensor membrane.

[0135] B46. The blood pump assembly of any of B1-B45, wherein the peripheral wall of the blood pump housing component includes one or more blood drainage windows.

[0136] B47. The blood pump assembly of any of B1-B46, wherein the peripheral wall of the blood pump housing component includes a transmission fiber bed, which is a recess in the peripheral wall of the blood pump housing component, and the transmission fiber of the sensor is positioned within the transmission fiber bed.

[0137] B48. The blood pump assembly of any of B1-B47, wherein the sensor includes a glass ring positioned around the transmission fiber.

[0138] B49. The blood pump assembly of any of B1-B48, wherein the sensor membrane has a thickness of 2 microns or less.

[0139] B50. The blood pump assembly of any of B1-B48, wherein the sensor membrane has a thickness of 1.3 microns or less.

[0140] B51. The blood pump assembly of any of B1-B50, wherein the sensor is positioned within a sensor bed within a peripheral wall of the blood pump housing component.

[0141] B52. The blood pump assembly of B46, wherein the blood pump housing component includes a plurality of struts extending between the blood drainage windows.

[0142] B53. The blood pump assembly of B52, wherein the transmission fiber bed is positioned within one of the struts of the blood pump housing component.

[0143] B54. The blood pump assembly of B53, wherein the transmission fiber is coupled to the one of the struts by epoxy resin.

[0144] B55. The blood pump assembly of any of B1-B54, wherein the impeller blade is positioned at least partially within the blood pump housing component.

[0145] B56. The blood pump assembly of any of B1-B55, wherein the blood pump housing component is coupled to the drive unit at a first end and to the cannula assembly at a second end opposite the first end.

[0146] B57. The blood pump assembly of any of B1-B56, wherein the cannula assembly includes a blood inflow cage.

[0147] B58. The blood pump assembly of B57, wherein the blood inlet cage includes a plurality of inlet openings.

[0148] B59. The blood pump assembly of any of B57-B58, further comprising a flexible atraumatic extension coupled to the blood inflow cage.

[0149] In a seventh additional aspect, a method of manufacturing a blood pump assembly includes coupling a sensor to a peripheral wall of a blood pump housing component, the sensor including a sensor membrane configured to deflect in response to a change in a blood parameter, the sensor membrane being coupled to a transmission fiber, the sensor including a sensor visor overhanging the sensor membrane; rotatably coupling an impeller blade to a drive unit such that the peripheral wall of the blood pump housing component extends about an axis of rotation of the impeller blade; and coupling a cannula assembly to the blood pump housing component.

[0150] B61. The method of B60, further comprising positioning the sensor visor within a visor notch of a barrier bump protruding from a peripheral wall of the blood pump housing component.

[0151] B62. The method of any of B60-B61, wherein coupling the sensor to the peripheral wall of the blood pump housing component comprises affixing the sensor to the peripheral wall of the blood pump housing component.

[0152] B63. The method of any of B60-B62, wherein the step of coupling the sensor to the peripheral wall of the blood pump housing component includes positioning the sensor in a blood cavity in the peripheral wall of the blood pump housing component.

[0153] B64. The method of B63, wherein the blood pump housing component includes a plurality of blood drainage windows and a plurality of struts extending between the blood drainage windows, and the blood recess is positioned within one of the struts within the blood pump housing component.

[0154] B65. The method of any of B60-B64, further comprising the step of connecting a blood inflow cage to the cannula assembly.

[0155] B66. The method of B65, further comprising the step of connecting a flexible atraumatic extension to the blood inflow cage.

[0156] B67. The method of any of B60-B66, further comprising the step of depositing a protective layer on the surface of the sensor membrane.

[0157] B68. Any of the methods of B60-B66, further comprising the steps of: depositing a protective layer on a surface of the sensor membrane; and positioning the sensor membrane further recessed below the sensor visor a distance approximately equal to the thickness of the protective layer.

[0158] B69. The blood pump assembly of any of B1-B68, wherein the sensor is a pressure sensor.

[0159] B70. A blood pump assembly according to any one of B1 to B69, wherein the sensor optically transmits a sensed signal.

[0160] B71. The blood pump assembly of B70, wherein the transmission fiber is an optical fiber.

[0161] B72. The blood pump assembly of any of B1-71, wherein the drive unit is driven by an external motor.

[0162] In an eighth additional aspect, a method of detecting blood pressure includes pumping blood through a cannula assembly coupled to a blood pump housing component, the blood being pumped by impeller blades positioned at least partially within the blood pump housing component, the impeller blades being rotated by a drive unit coupled to the impeller blades, the blood pump housing component including a circumferential wall extending about an axis of rotation of the impeller blades; and detecting the blood pressure of the pumped blood with an optical pressure sensor coupled to the circumferential wall of the blood pump housing component, the optical pressure sensor including a sensor membrane configured to deflect in response to changes in pressure on the sensor membrane, the sensor membrane being coupled to an optical fiber, and the optical pressure sensor including a sensor visor overhanging the sensor membrane.

[0163] B74. The method of B73, wherein the step of pumping blood includes pumping blood through one or more blood drainage windows in the blood pump housing component.

[0164] B75. The method of any of B73-B74, further comprising washing the sensor membrane with blood flow through a blood aperture extending through a peripheral wall of the blood pump housing component, the blood aperture being positioned within a blood well positioned in front of the sensor membrane of the optical pressure sensor.

[0165] B76. The method of B75, wherein the peripheral wall of the blood pump housing component includes a barrier bump protruding from the peripheral wall of the blood pump housing component, the barrier bump being positioned forward of the blood well such that the blood well is between the barrier bump and the sensor membrane.

[0166] B77. The method of B76, further comprising deflecting blood flowing through the blood aperture with a sensor visor extending from the optical pressure sensor onto the sensor membrane and into a visor notch in the barrier bump.

[0167] B78. The method of any of B73-B77, wherein the sensor membrane comprises a glass material.

[0168] B79. Any of the methods of B73-B78, wherein the sensor membrane faces toward the distal end of the pump.

[0169] B80. Any of the methods of B73-B79, wherein the sensor membrane is less than 2 microns thick.

[0170] B81. The method of any of B73 to B80, wherein a protective layer is deposited on the surface of the sensor membrane.

[0171] B82. The method of any of B73-B80, wherein a protective layer is applied onto the surface of the sensor membrane and the sensor membrane is further recessed below the sensor visor by a distance approximately equal to the thickness of the protective layer.

[0172] The foregoing is merely illustrative of the principles of the present disclosure, and the embodiments presented herein are intended to be illustrative and not limiting; the systems, methods, and devices of the present invention may be realized in other ways than those described. It should be understood that while the systems, devices, and methods disclosed herein have been shown for use in a blood pump assembly that may be percutaneously introduced through the vascular system during a cardiac therapy procedure, they may also be applied to systems, devices, and methods used in other types of therapies and devices that require sensors.

[0173] Variations and modifications will occur to those skilled in the art upon review of this disclosure. The disclosed features may be implemented in any combination or subcombination (including multiple independent combinations and subcombinations) with one or more other features described herein. The various features described or illustrated above, including any components thereof, may be combined or integrated into other systems. Additionally, certain features may be omitted or not implemented.

[0174] Examples of modifications, substitutions, and alternatives are ascertainable by one skilled in the art and can be made without departing from the scope of the information disclosed herein. All references cited herein are incorporated by reference in their entirety and made a part of this application.

Claims

1. A drive unit; an impeller blade rotatably connected to the drive unit; a blood pump housing component including a peripheral wall extending about an axis of rotation of the impeller blades; a cannula assembly coupled to the blood pump housing component; an optical pressure sensor coupled to the peripheral wall of the blood pump housing component, the optical pressure sensor including a sensor membrane coupled to an optical fiber; Equipped with 1. A blood pump assembly comprising: The optical pressure sensor comprises: detecting a blood pressure of blood pumped through the cannula assembly by the impeller blades; a deflection through the sensor membrane in response to changes in the blood pressure; The deflection is transmitted to the optical fiber. The blood pump assembly is configured as follows:

2. A blood pump assembly as described in claim 1, wherein blood is pumped through one or more blood exhaust windows in a blood pump housing component.

3. A blood pump assembly as described in claim 1, wherein the optical pressure sensor is further configured to sense a signal transmitted to the optical fiber to detect blood pressure.

4. A blood pump assembly as described in claim 3, wherein the optical pressure sensor includes a glass ring positioned around the optical fiber.

5. A blood pump assembly as described in claim 1, wherein the sensor membrane comprises a glass material.

6. A blood pump assembly as described in claim 1, wherein the sensor membrane has a thickness of less than about 2 microns.

7. A blood pump assembly as described in claim 1, wherein the optical pressure sensor includes a sensor visor extending over the sensor membrane.

8. A blood pump assembly as described in claim 7, further comprising a blood aperture extending through a peripheral wall of the blood pump housing component, the blood aperture being positioned within a blood recess positioned forward of the sensor membrane of the optical pressure sensor.

9. A blood pump assembly as described in claim 8, wherein a peripheral wall of a blood pump housing component includes a barrier bump protruding from the peripheral wall of the blood pump housing component, the barrier bump being positioned forward of the blood recess such that the blood recess is between the barrier bump and the sensor membrane.

10. The blood pump assembly of claim 9, wherein a sensor visor positioned within a visor notch in the barrier bump is configured to deflect blood flowing through the blood aperture.

11. The blood pump assembly of claim 8, wherein the blood aperture has a smooth surface to prevent blood clots.

12. The blood pump assembly of claim 8, wherein the blood cavity is wider than the optical pressure sensor.

Images