Patent Description:
During insertion of a blood pump assembly through a blood vessel, the torturous path and/or calcified anatomy can obstruct and damage components of the blood pump assembly. Damage to a blood pump assembly during insertion may require removal or replacement of the blood pump assembly. Because the blood pump assembly is designed for use in procedures that impact patient vitality, it is important that the blood pump assembly be capable of precise operation and delivery. Still further, it can be important to monitor the patient's interactions with the blood pump assembly.

<CIT> discloses an intravascular rotary blood pump comprising a catheter, a pump device fixed distally on the catheter and at least one pressure sensor which is securely connected to the pump device and which has a pressure-sensitive surface which is exposed to the environment and which is oriented perpendicular to the general longitudinal axis of the blood pump. Further background art can be found in <CIT>.

According to the invention, a blood pump assembly comprising the features of claim <NUM> is provided.

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 that covers at least a portion of the sensor membrane to protect the sensor from physical damage.

In some implementations, the shield includes a barrier bump positioned distal relative to the sensor membrane. In certain implementations, the blood pump assembly further includes a sensor visor to protect the sensor from physical damage, the sensor visor extending in a distal direction beyond the sensor membrane. In some implementations, the sensor visor extends into a visor notch formed in the barrier bump. In certain implementations, the blood pump assembly further includes a cap that covers the visor notch. In some implementations, the sensor visor is attached to the barrier bump by adhesive or welding. In certain implementations, the shield includes at least one protective layer covering a surface of the sensor membrane. In some implementations, the sensor membrane is recessed in a proximal direction relative to the sensor visor. The shield includes a blood aperture extending through the blood pump housing component and positioned distal relative to the sensor membrane for washing the sensor membrane with blood.

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 includes a sensor membrane configured to deflect in response to a change in a blood parameter, and the sensor is coupled to a transmission fiber. The blood pump assembly includes a passive protective mechanism for protecting the sensor from damage when the blood pump assembly is inserted into a patient.

In some implementations, the passive protective mechanism includes a barrier positioned distal to the sensor membrane. In certain implementations, the barrier protrudes from the blood pump housing component. In some implementations, the barrier is composed of the same material as the blood pump housing component. In certain implementations, the barrier has a smooth outer surface which contacts the blood. In some implementations, the barrier has a radial height approximately equal to or greater than a radial height of the sensor. In certain implementations, the blood pump assembly further includes one or more protective layers deposited on a surface of the sensor membrane facing toward a distal end of the blood pump assembly. In some implementations, the one or more protective layers include a single layer deposited over the sensor membrane and formed of a material capable of being deposited as a gel and curing. In certain implementations, the one or more protective layers include a material capable of preventing the sensor membrane from being dissolved by a chemical or biological reaction with blood. In some implementations, the one or more protective layers include a layer of silicone. In certain implementations, the one or more protective layers include a metal oxide. In some implementations, the sensor membrane has a thickness of <NUM> microns or less. In certain implementations, the sensor is positioned in a sensor bed in the blood pump housing component. In some implementations, the sensor is an optical sensor that transmits optical signals. In certain implementations, the blood pump housing component has a substantially cylindrical and elongate shape.

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 peripheral wall extending about a rotational axis of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the peripheral 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 that covers at least a portion of the sensor membrane.

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

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 peripheral wall extending about a rotational axis of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the peripheral 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 protective mechanism positioned distal relative to the sensor membrane.

In some implementations, the shield (for example, the passive protective mechanism) positioned distal relative to the sensor membrane includes a barrier positioned distal relative to the sensor membrane. In certain implementations, the shield (for example, the barrier) positioned distal relative to the sensor membrane includes a barrier bump positioned distal relative to the sensor membrane. The barrier bump may protrude from the peripheral wall of the blood pump housing component. In certain implementations, the shield (for example, the barrier or barrier bump) is composed of the same material as the blood pump housing component. In some implementations, the shield (for example, the barrier or barrier bump) has a smooth surface. In certain implementations, the shield (for example, the barrier or barrier bump) is composed of stainless steel. In some implementations, the shield (for example, the barrier or barrier bump) is electropolished or mechanically polished. In certain implementations, the shield (for example, the barrier or barrier bump) has a height approximately equal to or greater than the height of the sensor. In some implementations, the shield (for example, the barrier or barrier bump) has a visor notch configured to receive a sensor visor overhanging the sensor membrane.

In certain implementations, the shield of the blood pump assembly includes a passive protective mechanism positioned such that the sensor membrane is positioned between the passive protective mechanism and the peripheral wall of the blood pump housing component. In some implementations, the shield (for example, the passive protective 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 implementations, the shield (for example, 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 implementations, the sensor visor is stainless steel. In certain implementations, the sensor visor has a smooth surface. In some implementations, the sensor visor includes a biocompatible material. In certain implementations, the sensor visor is coated by a biocompatible material.

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 peripheral wall extending about a rotational axis of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the peripheral 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 protective mechanism covering a surface of the sensor membrane.

In some implementations, the shield (for example, the passive protective mechanism) covering the surface of the sensor membrane includes a barrier covering the surface of the sensor membrane. In certain implementations, the shield (for example, the barrier) covering the surface of the sensor membrane includes a protective layer deposited on the surface of the sensor membrane. In some implementations, the sensor membrane faces toward a 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 implementations, the protective layer has a thickness approximately equal to <NUM> or greater. In some implementations, the protective layer has a thickness approximately equal to <NUM> or greater. In certain implementations, the protective layer includes a material capable of being deposited as a gel and hardening. In some implementations, the protective layer includes a material capable of preventing the sensor membrane from being dissolved by a chemical reaction with blood. In certain implementations, the protective layer includes silicone.

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 peripheral wall extending about a rotational axis of the impeller blade. The impeller blade is rotatably coupled to the drive unit. The sensor is coupled to the peripheral 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 protective mechanisms for the sensor membrane.

In some implementations, the shield (for example, the one or more active protective mechanisms) includes a mechanism for washing the sensor membrane, for example, a mechanism for washing the sensor membrane with blood. In some implementations, the mechanism for washing 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 distal relative to the sensor membrane. In certain implementations, the peripheral wall of the blood pump housing component includes a recess positioned distal relative to the sensor membrane. In some implementations, the recess is wider than the sensor. In certain implementations, the blood aperture is positioned in the recess. In some implementations, the blood aperture permits blood flowing through the cannula assembly and into the blood pump housing component to exit the blood pump housing component and wash the sensor membrane.

In some implementations, the peripheral wall of the blood pump housing component includes one or more blood exhaust windows. In certain implementations, the peripheral wall of the blood pump housing component includes a transmission fiber bed recessed within the peripheral wall of the blood pump housing component, the transmission fiber of the sensor positioned in the transmission fiber bed. The transmission fiber is used to transmit signals sensed by the sensor to a processor for detecting the blood parameter. In some implementations, the sensor includes a glass ring positioned about the transmission fiber.

In certain implementations, the sensor membrane has a thickness of <NUM> microns or less. In some implementations, the sensor membrane has a thickness of <NUM> microns or less. In certain implementations, the sensor is positioned in a sensor bed in the peripheral wall of the blood pump housing component. In some implementations, the blood pump housing component includes a plurality of struts extending between the blood exhaust windows. The transmission fiber bed may be positioned in a strut of the plurality of struts of the blood pump housing component. In some implementations, the transmission fiber is coupled to the strut of the plurality of struts by an epoxy. The impeller blade may be positioned at least in part in the blood pump housing component. In some implementations, the blood pump housing component is coupled to the drive unit at a first end and the blood pump housing component is coupled to the cannula assembly at a second end opposite the first end. In certain implementations, the cannula assembly includes a blood inflow cage. In some implementations, the blood inflow cage includes a plurality of inlet openings. In certain implementations, a flexible atraumatic extension (for example, a pigtail) is coupled to the blood inflow cage.

In an example which does not form part of the invention, 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 a rotational axis 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.

In some implementations, the method further includes positioning a sensor visor in a visor notch of a barrier bump protruding from the peripheral wall of the blood pump housing component. In certain implementations, coupling the sensor to the peripheral wall of the blood pump housing component includes affixing (for example, by an epoxy) the sensor to the peripheral wall of the blood pump housing component. In some implementations, coupling the sensor to the peripheral wall of the blood pump housing component includes positioning the sensor into a blood recess in the peripheral wall of the blood pump housing component. In certain implementations, the blood pump housing component includes a plurality of blood exhaust windows and a plurality of struts extending between the blood exhaust windows, and the blood recess is positioned in a strut of the plurality of struts in the blood pump housing component. In some implementations, the method further includes coupling a blood inflow cage to the cannula assembly. In certain implementations, the method further includes coupling a flexible atraumatic extension to the blood inflow cage. In some implementations, a protective layer is deposited over a surface of the sensor membrane. In certain implementations, a protective layer is deposited over a 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.

The sensor detects one or more disturbances or properties of the blood (for example, a deflection caused by a pressure that is used to determine a blood parameter signal). In some implementations, the sensor is a pressure sensor or flow rate sensor. In certain implementations, the sensor transmits its sensed signals optically. In some implementations, the transmission fiber is an optical fiber. In certain implementations, the drive unit is driven by an external motor.

In an example which does not form part of the invention, a method of detecting blood pressure includes pumping blood through a cannula assembly coupled to a blood pump housing component and detecting a blood pressure of the blood pumped using an optical pressure sensor coupled to the peripheral wall of the blood pump housing component.

The blood is pumped by an impeller blade positioned at least in part in 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 a rotational axis of the impeller blade. The optical pressure sensor includes a sensor membrane configured to deflect in response to a change 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.

In some implementations, pumping blood includes pumping blood through one or more blood exhaust windows in the blood pump housing component. In certain implementations, the method further includes washing the sensor membrane using blood flow through a blood aperture extending through the peripheral wall of the blood pump housing component. The blood aperture is positioned in a blood recess positioned in front of the sensor membrane of the optical pressure sensor. In some implementations, 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 recess, such that the blood recess is between the barrier bump and the sensor membrane. In certain implementations, the method further includes deflecting the blood flowing through the blood aperture using a sensor visor extending from the optical pressure sensor over the sensor membrane and into a visor notch in the barrier bump. In some implementations, the sensor membrane includes a glass material. In certain implementations, the sensor membrane faces toward a distal end of the pump. In some implementations, the sensor membrane is less than <NUM> microns thick. In some implementations, a protective layer is deposited over a surface of the sensor membrane. In certain implementations, a protective layer is deposited over a 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.

Moreover, certain concepts may be omitted or not implemented.

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 contemplated herein, certain illustrative embodiments will be described. Although the embodiments and features described herein are specifically described for use in connection with blood pump assemblies that may be introduced percutaneously during a cardiac procedure through the vascular system, it will be understood that all the components and other features outlined below may be combined with one another in any suitable manner and may be adapted and applied to other types of cardiac therapy and cardiac therapy devices.

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 can enable the blood pump assembly and sensor to traverse torturous and/or calcified anatomy of the vascular system and remain operable. such as by protecting the sensor membrane. The shield may include one or more passive protective mechanisms, active protective mechanisms, or a combination of both. Passive protective mechanisms may include one or more barriers which protect the sensor membrane. As an example, a sensor visor may prevent soft obstructions, such as valve leaves on a blood pump introducer, from contacting and damaging the sensor membrane. A barrier bump is another example of a passive protective mechanism and can be positioned distal relative to the sensor membrane. The barrier bump may deflect calcification or other obstacles within the vascular system and/or prevent the sensor membrane from being damaged when the pump changes direction during delivery of the pump through the vasculature and into the heart. The shield may also include an additional protective layer (for example, a layer of silicone) covering the sensor membrane. As an example, this protective layer may prevent the sensor membrane from being dissolved by chemical reactions with a patient's blood without significantly influencing or interfering with accurate detection of pressure. A mechanism for washing the sensor membrane is an example of an active protective mechanism for the sensor. For example, a blood aperture can be positioned adjacent to the sensor membrane and blood flowing through the aperture may wash the front end of the sensor membrane to prevent buildup or clotting of blood on the surface of the sensor membrane.

<FIG> is a side view of an exemplary catheter-based blood pump assembly <NUM> having a sensor <NUM> and exemplary shielding features for protecting the sensor <NUM>. <FIG> is a top view of the blood pump assembly <NUM>, and <FIG> is a partial top view of the blood pump assembly <NUM>. As shown, the blood pump assembly <NUM> includes a cannula assembly <NUM>, the sensor <NUM>, a catheter shaft <NUM>, a flexible atraumatic extension (for example, a pigtail) <NUM>, a blood pump motor <NUM>, a blood pump motor housing <NUM>, a blood pump housing component <NUM>, a drive shaft <NUM>, an impeller hub <NUM>, a blood inflow cage <NUM>, and a guidewire hole <NUM>. The pigtail extension <NUM> includes a curved portion <NUM>. The blood inflow cage <NUM> includes one or more input ports <NUM>. The interior of the blood pump housing component <NUM> is contiguous with the interior of the cannula assembly <NUM>. The cannula assembly <NUM> is coupled to the blood pump housing component <NUM> and the blood pump housing component <NUM> is coupled to the blood pump motor housing <NUM>. The blood pump housing component has a substantially cylindrical and elongate shape. The blood pump motor <NUM> is housed in the blood pump motor housing <NUM>. As an alternative, in certain other implementations, the blood pump motor <NUM> has an integrated housing such that the outer layer of the blood pump motor <NUM> is the blood pump housing <NUM>.

As used herein, "distal" means in the direction in which the blood pump assembly is inserted into a blood vessel. and "proximal" is opposite the distal direction. For example, in <FIG>, the extension <NUM> is distal to the sensor <NUM> and the catheter shaft <NUM> is proximal to the sensor <NUM>.

The cannula assembly <NUM> includes the blood inflow cage <NUM>, which is positioned toward the distal end of the cannula assembly <NUM> opposite from the proximal blood pump housing component <NUM>. The catheter shaft <NUM> extends from the blood pump motor housing <NUM> at the proximal end of the blood pump assembly <NUM>. The flexible atraumatic extension (for example, pigtail) <NUM> extends distally from the blood inflow cage <NUM> at the distal end of the blood pump assembly <NUM>. The blood pump assembly <NUM> may be configured as a pump for the left side of the heart or for the right side of the heart.

The sensor <NUM> may sense blood pressure, blood flow rate, and/or other parameters. The sensor <NUM> transmits its sensed signals to a transducer system to convert the signal into the desired physical or medical variable including signal conditioning and data acquisition system for linearization and calibration of the parameter. For example, the sensor <NUM> may be an optical pressure sensor that transmits optical signals or an electrical sensor.

The cannula assembly <NUM> provides at least one central lumen <NUM> configured to facilitate blood flow therein. The cannula assembly <NUM> includes a bend <NUM>. In some embodiments, the bend <NUM> is <NUM>°. One skilled in the art will appreciate that other configurations for the cannula assembly <NUM> are possible. In certain implementations being designed for use in the right heart, the cannula assembly <NUM> can have one or more bends and may have different and/or multiple bend radii to adapt to the needs of passage and final position of the cannula assembly <NUM>. In certain embodiments, the cannula assembly <NUM> need not have a bend. In certain embodiments, the diameter of the cannula assembly <NUM> is about equal to or greater than <NUM> Fr (<NUM>). For example, the diameter of the cannula assembly <NUM> may be <NUM> Fr (<NUM>), <NUM> Fr (<NUM>), <NUM> Fr (<NUM>), <NUM> Fr (<NUM>), > <NUM> Fr, or any other suitable diameter. In some embodiments, the diameter of the cannula assembly <NUM> is about equal to or less than <NUM> Fr (<NUM>). For example, the diameter of the cannula assembly <NUM> may be <NUM> Fr (<NUM>), <NUM> Fr (<NUM>), <NUM> Fr (<NUM>), < <NUM> Fr, or any other suitable diameter.

The drive shaft <NUM> transfers torque from the blood pump motor <NUM> to the impeller hub <NUM>. For example, a proximal end portion (not shown) of the drive shaft <NUM> can be coupled to a rotor of the blood pump motor <NUM> and a distal end (not shown) of the drive shaft <NUM> can be coupled to the impeller hub <NUM>. In some embodiments, a flexible drive cable, a magnetic clutch, and/or magnetic drive components transfer torque from the blood pump motor <NUM> to the impeller hub <NUM>. In certain embodiments, the blood pump motor110 can be positioned external to the patient and configured to rotate the rotor of the blood pump motor <NUM> when the blood pump assembly <NUM> is positioned in the patient's heart, and a drive shaft or drive cable can be coupled to the rotor of the blood pump motor <NUM>. In such embodiments, the blood pump motor <NUM> is absent from the blood pump motor housing <NUM>. For those embodiments, the blood pump motor housing <NUM> is modified to reduce rigid diameter and/or length of the pump.

The cannula assembly <NUM> also includes a blood inflow cage <NUM> positioned toward an opposite end of the cannula assembly <NUM> than the blood pump housing component <NUM>. The blood inflow cage <NUM> includes one or more input ports <NUM>. The blood pump assembly <NUM> is configured such that actuation of the blood pump motor <NUM> and the drive shaft <NUM> rotates the impeller hub <NUM> (which may include an impeller blade not shown in <FIG>) and draws blood or other fluid into the blood inflow cage <NUM> (or blood inlet manifold) through the one or more input ports <NUM>. The blood received through the blood inflow cage <NUM> travels through the cannula assembly <NUM> to the blood pump housing component <NUM>. The blood entering the blood pump housing component <NUM> is exhausted from the blood pump housing component <NUM> through windows or blood exhaust apertures (not shown in figure) in an outflow cage at a proximal end of the blood pump housing component <NUM>. In some embodiments, the flow direction can be opposite as that of the devices illustrated herein. In such embodiments, inflow of blood occurs at the side of the cannula assembly <NUM> which is connected to the blood pump housing component <NUM> and outflow of blood occurs at the opposite side of the cannula assembly <NUM>. When placed in a patient, the blood pump assembly <NUM> can pump blood from the left ventricle (via the blood inflow cage <NUM>) to the aorta (via the blood exhaust apertures). The blood pump assembly <NUM> includes a catheter shaft <NUM> extending from the blood pump motor housing <NUM> at the proximal end of the blood pump assembly <NUM>. The catheter shaft <NUM> houses electrical connector cables providing power and control signals to the blood pump motor <NUM> and receiving information from one or more sensors such as the sensor <NUM>, discussed further herein in accordance with particular embodiments. In some embodiments, the catheter shaft <NUM> includes one or more lumens to facilitate receipt of purge fluid and to be used as a conduit for a transmission fiber. In some embodiments, the interior of one or more lumens of the catheter shaft <NUM> is coated with a polytetrafluoroethylene (PTFE) lining, e.g., Teflon, over at least a portion of the one or more lumens' length. Because the PTFE lining has a low coefficient of friction, the transmission fiber moves more freely through the one or more lumens, and is easier to insert or retract as needed.

The blood pump assembly <NUM> includes a flexible atraumatic extension <NUM> (for example, a pigtail) extending from the blood inflow cage <NUM> at a distal end of the blood pump assembly <NUM>. The extension <NUM> includes a curved portion <NUM>. The extension <NUM> assists with stabilizing the blood pump assembly <NUM> in the correct position, for example in the left ventricle. In certain embodiments, the extension <NUM> is configurable from a straight configuration to a partially curved configuration. Accordingly, the extension <NUM> may be composed, at least in part, of a flexible material.

<FIG> show various views of the sensor <NUM> mounted on the blood pump assembly <NUM> of <FIG>. <FIG> is a magnified perspective view of the sensor <NUM> mounted on an outflow cage <NUM> of the blood pump assembly <NUM> of <FIG>. <FIG> is a magnified side view of the sensor <NUM> and the outflow cage <NUM> of <FIG>. <FIG> is a magnified end view of the blood pump assembly <NUM> of <FIG> showing the impeller hub <NUM>, impeller blade <NUM>, and exemplary shielding features for protecting the sensor <NUM>. <FIG> is a magnified end view of the sensor <NUM> and shielding features of the blood pump assembly <NUM> of <FIG>. <FIG> is a perspective view of the blood pump assembly <NUM> of <FIG> showing a cap and cover which provide smooth transitions between the outflow cage <NUM> and the shielding features. For clarity, the cannula assembly <NUM> is omitted from <FIG>.

As shown, the blood pump assembly <NUM> can include a shield. The shield may include a sensor visor, a barrier bump, an additional protective layer (for example, a silicone layer), and/or a blood aperture (embodiments without the blood aperture are not covered by the claims). In <FIG>, for example, the shield includes a sensor visor <NUM>, a barrier bump <NUM>, and a blood aperture <NUM>. In <FIG>, the blood pump assembly <NUM> further includes a plurality of struts <NUM>, one or more output ports <NUM>, a sensor bed <NUM>, a transmission fiber <NUM>, a recess <NUM>, an impeller blade <NUM>, and a transmission fiber bed <NUM>. The blood pump housing component <NUM> includes the outflow cage <NUM>. The sensor <NUM> includes a sensor head <NUM> and a sensor membrane <NUM>. In embodiments having both a barrier bump <NUM> and a sensor visor <NUM>, the barrier bump <NUM> may include a mechanism for connecting to the sensor visor <NUM>. For example, in <FIG>, the barrier bump <NUM> includes a visor notch <NUM> that receives and holds a portion of the sensor visor <NUM> in a fixed position. The sensor <NUM> is attached to the outflow cage <NUM> of the blood pump housing component <NUM>. For example, in <FIG>, the sensor <NUM> is coupled distal to one of the plurality of struts <NUM> of the outflow cage <NUM> of the blood pump housing component <NUM> and sits in the sensor bed <NUM>. Preferably, the sensor <NUM> is not positioned on one of the plurality of struts <NUM>. For example, in some embodiments, the sensor <NUM> is positioned on a portion of the outflow cage <NUM> distal to the struts <NUM> (e.g., <NUM>. <NUM> distal, <NUM>,<NUM> distal, <NUM> distal, <NUM> distal, <NUM> distal, <NUM> distal or any other suitable distance). Alternatively, the sensor <NUM> can be positioned on the blood inflow cage (e.g., blood inflow cage <NUM>) or on the cannula (e.g., cannula assembly <NUM>).

The sensor membrane <NUM> of the sensor <NUM> is configured to deflect in response to changes in blood parameters, for example, changes in pressure, flow rate, fluid composition, and/or viscosity. The sensor membrane <NUM> is preferably thin. In some embodiments, the sensor membrane <NUM> is less than two microns thick. In some embodiments, the sensor membrane <NUM> is composed of a fragile glass material such as silicon, silicon dioxide, or silicon nitride. Deflections of the sensor membrane <NUM> are used to measure changes in blood parameters (for example, blood pressure) at the blood pump assembly <NUM>. Due to the bend radius constraints of the transmission fiber <NUM>, the sensor membrane <NUM> points forward towards the distal end of the blood pump assembly <NUM>. Deflections of the sensor membrane <NUM> are sensed by the sensor head <NUM> and transmitted to the transmission fiber <NUM>. The transmission fiber <NUM> transmits the sensor's sensed signals to an optical bench for signal evaluation. The transmission fiber <NUM> can extend across various locations on the blood pump assembly <NUM> depending on the location of the sensor <NUM> relative to other components of the blood pump assembly <NUM>. In <FIG>, the transmission fiber <NUM> extends along one of the plurality of starts <NUM> of the blood pump housing component <NUM>, along the blood pump motor housing <NUM>, and through the catheter shaft <NUM> (not shown). In some embodiments, the transmission fiber <NUM> is coated with a protective coating, such as a polymer (for example, polyimide). The transmission fiber <NUM> is attached to the blood pump housing component <NUM>. In <FIG>, for example, the transmission fiber <NUM> is positioned in the transmission fiber bed <NUM> recessed in the outflow cage <NUM> of the blood pump housing component <NUM>. The measured blood parameters (for example, pressure) and changes in such parameters provide information regarding operation of the blood pump assembly <NUM>, the location of the blood pump assembly <NUM> (for example, in pressure sensor embodiments, pressure differences are associated with various locations in the heart), and vital signs of the patient in response to placement and operation of the blood pump assembly <NUM>.

In embodiments with sensors that transmit sensed signals optically, the transmission fiber <NUM> is an optical fiber and the transmission fiber <NUM> extends to a light source. In such embodiments, the reflection of light or resonant frequencies (e.g., in embodiments using the sensing principle of a Fabry-Perot resonator) within the sensor head <NUM> changes in response to changes in the position of the sensor membrane <NUM> under deflection in response to changes in blood parameters. Changes in the reflection of light or resonant frequencies are transmitted by the transmission fiber <NUM> from the sensor head <NUM> to an optical bench (or other suitable components configured to convert optically modulated pressure signal into electrically calibrated or digital data which can be stored and/or analyzed using software) for signal evaluation. The optical bench may be remote from the blood pump housing component <NUM>, for example located outside of the body in a console or in a connector. In embodiments with sensors that sense pressure, the movement of the sensor membrane <NUM> in response to changes in pressure on the surface of the sensor membrane <NUM> is transmitted by the transmission fiber <NUM> to an optical bench or transducer for pressure determination. The sensors may transmit sensed pressure signals optically, as discussed above.

The barrier bump <NUM> is positioned in front of/distal to the sensor membrane <NUM> to protect the sensor membrane <NUM>. The barrier bump <NUM> protrudes from the outflow cage <NUM> of the blood pump housing component <NUM>. In some embodiments, the barrier bump <NUM> is composed of the same material as the blood pump housing component <NUM>, such as stainless steel. The barrier bump <NUM> may be electropolished, mechanically polished, or otherwise processed in such a way that it provides smooth surfaces that minimize thrombosis and blood flow shear stress. In particular, it is preferred that all surfaces of the barrier bump <NUM> which will be in contact with blood be smooth so as to minimize thrombosis and blood flow shear stress. The sensor <NUM> may include various other protective features. In embodiments having both a barrier bump <NUM> and a sensor visor <NUM>, such as the embodiment shown in <FIG>, the barrier bump <NUM> may include a visor notch <NUM> configured to receive and hold the sensor visor <NUM> in a fixed position. Other mechanisms could be employed for connecting the sensor visor <NUM> to the barrier bump <NUM>, such as adhesive (for example, epoxy), welding, etc..

As shown, the sensor visor <NUM> can be a shroud that extends over the sensor membrane <NUM>. In embodiments having both a barrier bump <NUM> and a sensor visor <NUM>, such as the embodiment shown in <FIG>, the sensor visor <NUM> may extend to the visor notch <NUM> in the barrier bump <NUM>. The sensor visor <NUM> helps to direct or deflect flow of blood exiting the blood pump housing component <NUM> through the blood aperture <NUM>. The sensor visor <NUM> deflects blood to the sensor membrane <NUM> of the sensor <NUM> and out to the sides through the recess <NUM>. In some embodiments, the sensor visor <NUM> is composed of stainless steel. The sensor visor <NUM> may have a curved geometry. The sensor visor <NUM> preferably has smooth surfaces for some or all of its surfaces in contact with blood so as to prevent thrombosis. The sensor visor <NUM> may be composed, at least in part, of a biocompatible material and/or may have a biocompatible material coating.

As discussed herein, a blood pump assembly <NUM> may be introduced percutaneously during a cardiac procedure through the vascular system. For example, the blood pump assembly <NUM> can be inserted by a catheterization procedure through the femoral artery, into the ascending aorta, across the valve, and into the left ventricle such that the blood pump assembly <NUM> can provide support to the left side of the heart. As noted, introducing the blood pump assembly <NUM> through an introducer unit into the vascular system may include traversing torturous directional changes and a calcified anatomy in the vascular system. The sensor <NUM>, and in particular the sensor membrane <NUM>, may be composed of sensitive or brittle components that may be easily damaged by the torturous and calcified anatomy of the vascular system. The barrier bump <NUM> and the sensor visor <NUM> permit the sensor <NUM> to traverse the torturous and calcified anatomy of the vascular system and remain operable. For example, the barrier bump <NUM> may protect the sensor membrane <NUM> by deflecting upcoming obstacles presented by calcification within the vascular system or changes in direction of the sensor <NUM>. As another example, the sensor visor <NUM> may protect the sensor membrane <NUM> by preventing soft obstructions, such as valve leaves on a blood pump introducer, from contacting and damaging the sensor membrane <NUM>. In embodiments having both a barrier bump <NUM> and a sensor visor <NUM>, such as the embodiment shown in <FIG>, obstacles deflected by the barrier bump <NUM> may ride over the sensor visor <NUM>, thereby preventing the obstacles from contacting and/or damaging the sensor membrane <NUM>.

The sensor membrane <NUM> is positioned in the recess <NUM> and positioned adjacent to the blood aperture <NUM>. The recess <NUM> is where blood flowing from cannula assembly <NUM> is introduced to and directly or indirectly interacts with the sensor membrane <NUM> so that the fluid pressure may be determined. In <FIG>, blood can directly interact with the sensor membrane <NUM>. In embodiments in which there are one or more protective layers deposited over the sensor membrane <NUM> (as discussed below in relation to <FIG>), blood indirectly interacts with the sensor membrane <NUM>. The recess <NUM> is configured to be wider than the sensor <NUM> so that the blood can easily flow away, for example laterally, from the sensor <NUM>, allowing for pressure equivalence with the pressure on the outside of the outflow cage <NUM> of the blood pump housing component <NUM>. In some embodiments, the width of the recess <NUM> is configured to be about equal to or less than the width of the sensor <NUM>.

The blood aperture <NUM> can allow blood to flow toward the sensor membrane <NUM> and then exit the blood pump housing component <NUM>. In the illustrated embodiment, the blood aperture <NUM> is positioned distal to the sensor membrane <NUM> and the blood aperture <NUM> is in the recess <NUM>. The blood aperture <NUM> permits blood flowing through the cannula assembly <NUM> to wash the front end of the sensor membrane <NUM> to prevent buildup or clotting of blood on the surface of the sensor membrane <NUM>. As shown, the blood aperture <NUM> extends from the interior of the blood pump housing component <NUM> into the recess <NUM>. The blood aperture <NUM> also permits blood flowing from the cannula assembly <NUM> into the blood pump housing component <NUM> to exit the blood pump housing component <NUM> in a manner similar to the way that blood exits the blood pump housing component <NUM> through the one or more output ports <NUM>. Blood exiting the blood pump housing component <NUM> through the blood aperture <NUM> flows past the sensor membrane <NUM> in the recess <NUM>. The blood aperture <NUM> may be approximately <NUM> microns in diameter. In some embodiments, the diameter of the blood aperture <NUM> is greater than <NUM> microns, for example, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, > <NUM> microns, or any suitable diameter. In other embodiments, the diameter of the blood aperture <NUM> is less than <NUM> microns, for example, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, < <NUM> microns, or any suitable diameter. In some embodiments the flow can be directed inwards. In certain embodiments, the flow can be bidirectional and blood can enter and exit the blood aperture <NUM>, washing the sensor membrane <NUM>. The blood aperture <NUM> preferably has smooth surfaces for some or all of its surfaces in contact with blood so as to prevent thrombosis. In embodiments where the sensor <NUM> and the sensor membrane <NUM> are positioned more distal than the positioning shown in <FIG>, the likelihood of clotting of blood increases and the blood aperture <NUM> becomes more important. In other embodiments in which the sensor <NUM> and the sensor membrane <NUM> are positioned more proximally than the positioning shown in <FIG>, it may not be necessary to have a blood aperture <NUM>, and instead the sensor membrane <NUM> can be directly open with the blood (embodiments without the blood aperture are not covered by the claims).

The sensor <NUM> can be attached to the outflow cage <NUM> of the blood pump housing component <NUM> (or other components of the blood pump assembly <NUM>, such as the inflow cage107) in various ways. In <FIG>, the sensor <NUM> sits in the sensor bed <NUM>, which is configured to receive the sensor <NUM> in a recessed position in the outflow cage <NUM> of the blood pump housing component <NUM>. The sensor bed <NUM> extends directly into the recess <NUM> to provide and facilitate an interface between the sensor membrane <NUM> and the blood entering the recess <NUM> through the blood aperture <NUM>. In some embodiments, the sensor bed <NUM> includes laser texturing strips to facilitate placement and holding of the sensor <NUM> therein. In certain embodiments, the sensor bed <NUM> includes potting and/or smoothing by the use of epoxy or silicone to smooth structures in and/or around the sensor bed <NUM>.

As shown in <FIG>, an opening/window <NUM> allows blood exiting or entering the blood aperture <NUM> (shown in <FIG>) to wash the sensor membrane <NUM>. The barrier bump <NUM> is structured to have a height that is greater than the height (e.g. in a direction radially outward from a central longitudinal axis extending through the blood pump assembly <NUM>) of the sensor <NUM> to raise the position of any obstacles encountered during insertion of the sensor <NUM>. The obstacles are then able to rise over and be diverted away from the sensor <NUM> and in particular over the sensor membrane <NUM>. For example, the obstacles can ride along the sensor visor <NUM> without contacting the sensor membrane <NUM>. The sensor <NUM> is recessed in the outflow cage <NUM> of the blood pump housing component <NUM> distal to one of the plurality of struts <NUM>. Positioning the sensor <NUM> more distal on the blood pump housing component <NUM> than the position shown in <FIG> can help with repositioning the blood pump assembly <NUM>. In some embodiments, the sensor <NUM> and/or the sensor visor <NUM> may be coupled to the outflow cage <NUM> of the blood pump housing component <NUM> (or another component of the blood pump assembly <NUM>, such as the inflow cage <NUM>) and the barrier bump <NUM> with an adhesive, including but not limited to an epoxy, may be welded, or may be coupled together using other fixation techniques known to persons skilled in the art.

The blood pump housing component <NUM> can house the drive shaft <NUM> which can be coupled to the blood pump motor <NUM> to permit axial rotation of the drive shaft <NUM>. The drive shaft <NUM> is coupled to the impeller hub <NUM> at a distal end portion of the drive shaft <NUM>. The impeller hub <NUM> is coupled to the impeller blade <NUM>. The impeller blade <NUM> draws blood through the cannula assembly <NUM> to create a highly viscous helical flow of blood, the blood exiting the blood pump housing component <NUM> through a plurality of blood exhaust windows <NUM> provided in the sidewall of the outflow cage <NUM> of the blood pump housing component <NUM>. In some embodiments, the exhaust windows are formed in walls of the cannula assembly <NUM> instead of or in addition to being formed in the blood pump housing component <NUM>. The impeller blade <NUM> may be expandable or compressible. The outflow cage <NUM> includes a plurality of struts <NUM> positioned around the outflow cage <NUM>.

The plurality of struts <NUM> separate the one or more output ports <NUM>. At least one of the plurality of struts <NUM> includes the transmission fiber bed <NUM> for the transmission fiber <NUM> and aligns to the sensor bed <NUM> and the transmission fiber bed <NUM> (shown in <FIG>) for housing the sensor <NUM> and the transmission fiber <NUM>, respectively.

In some embodiments, the blood pump assembly <NUM> includes features providing smooth transitions over certain structures of the blood pump assembly <NUM>. As shown in <FIG>, a cap <NUM> covers the visor notch <NUM> (not visible in figure) when the sensor visor <NUM> is properly positioned. The cap <NUM> may include an adhesive, epoxy, weld, or other structure or material that can hold the sensor visor <NUM> in place and/or provide a smooth transition across the barrier bump <NUM>. Similarly, the sensor <NUM> and/or the transmission fiber <NUM> (not visible) are coupled to the outflow cage <NUM> of the blood pump housing component <NUM> through a cover <NUM>, which may include but is not limited to a layer of epoxy providing a smooth transition across the sensor <NUM> as well as securing the sensor <NUM> and the transmission fiber <NUM> in place. One skilled in the art will appreciate that various other features providing smooth transitions over certain structures of the blood pump assembly <NUM> are possible. Preferably, all surfaces of the blood pump assembly <NUM> that touch blood are smooth to minimize thrombosis and blood flow shear stress.

<FIG> is a side view of a sensing assembly <NUM> for a catheter-based blood pump assembly. The sensing assembly <NUM> includes a sensor <NUM>, a sensor visor <NUM>, a transmission fiber <NUM>, and a connector <NUM>. The sensor <NUM> includes a sensor head <NUM> and a sensor membrane <NUM>. The sensor head <NUM> houses sensing components. The sensor visor <NUM> may be composed of a material including but not limited to stainless steel. The transmission fiber <NUM> extends from the connector <NUM> to the sensor head <NUM>. In embodiments where the sensing assembly <NUM> senses pressure and transmits sensed signals optically, the transmission fiber <NUM> optically couples the sensor head <NUM> , through the connector <NUM>, to a light source configured to send light to the sensor membrane <NUM> and the modulated signal back to the optical bench/transducer. As pressure is applied to the sensor membrane <NUM> under the high pressure and/or vacuum caused by the impeller blade (not shown in figure) rotating, the sensor membrane <NUM> deflects, causing a change/modulation of the reflected light which is sent back from the sensor head <NUM>. The change in the light is detected on behalf of the optical bench/transducer and the change in pressure is determined.

<FIG> is a partial side cross-sectional view of a sensing assembly <NUM> for a catheter-based blood pump assembly. The sensing assembly <NUM> includes a sensor <NUM>, a transmission fiber <NUM>, a jacket <NUM>, glue <NUM>, and a sensor visor <NUM>. The sensor <NUM> includes a sensor head <NUM>, a sensor membrane <NUM>, and a temperature compensation portion <NUM>. The sensor head <NUM> includes a cavity <NUM>. The transmission fiber <NUM> ends in the proximal portion of the sensor head <NUM> to which it is coupled with low loss. The cavity <NUM> in combination with the sensor membrane <NUM> forms a Fabry-Perot resonator. To allow for the resonant measuring principle, both sides of the cavity <NUM> are manufactured to reflect light. As far as detection of the signal has to be made possible, on one side, preferably the transmission fiber <NUM> side, partial reflection is realized, and preferably on the sensor membrane <NUM> side, full reflection is realized. The temperature compensation portion <NUM> is configured to prevent drift in sensed signals due to temperature fluctuations. The temperature compensation portion <NUM> is smaller in size than the sensor membrane <NUM> and may include silicon dioxide. The jacket <NUM> is positioned about the transmission fiber <NUM> and may include a glass ring. The transmission fiber <NUM> is coupled to the sensor head <NUM> by the glue <NUM>, which may be ultraviolet-curing epoxy. The sensor visor <NUM> is configured to extend beyond a distal end of the sensor membrane <NUM>.

The shield for the blood pump assembly <NUM> can be configured in other ways. In <FIG>, the shield includes an additional protective layer covering the sensor membrane. <FIG> is a partial side cross-sectional view of another sensing assembly <NUM> including an additional protective layer covering the sensor membrane. As shown, the sensing assembly <NUM> includes a sensor <NUM>, a transmission fiber <NUM>, a jacket <NUM>, glue <NUM>, a sensor visor <NUM>, and a thin layer <NUM>. The sensor <NUM> includes a sensor head <NUM>, a sensor membrane <NUM>, and a temperature compensation portion <NUM>. The sensor head <NUM> includes a cavity <NUM>. The transmission fiber <NUM> ends in the proximal portion of the sensor head <NUM> to which it is coupled with low loss. The cavity <NUM> in combination with the sensor membrane <NUM> forms a Fabry-Perot resonator. To allow for the resonant measuring principle, both sides of the cavity <NUM> are manufactured to reflect light. As far as detection of the signal has to be made possible, on one side, preferably the transmission fiber <NUM> side, partial reflection is realized, and preferably on the sensor membrane <NUM> side, full reflection is realized. The temperature compensation portion <NUM> is configured to prevent drift in sensed signals due to temperature fluctuations. The temperature compensation portion <NUM> is smaller in size than the sensor membrane <NUM> and may include silicon dioxide. The jacket <NUM> is positioned about the transmission fiber <NUM> and may include a glass ring. The transmission fiber <NUM> is coupled to the sensor head <NUM> by the glue <NUM>, which may be ultraviolet-curing epoxy. The sensor visor <NUM> is configured to extend beyond a distal end of the sensor membrane <NUM>. The thin layer <NUM> is encapsulated over and covers the sensor membrane1123, and protects the sensor membrane <NUM> from damage due to the flow of blood over the sensor membrane <NUM>. For example, the thin layer <NUM> can prevent the sensor membrane11 <NUM> from being dissolved by a chemical reaction with the patient's blood. Additionally, the thin layer <NUM> impedes biological deposits from forming directly on the sensor membrane <NUM>.

The thin layer <NUM> may include material capable of being deposited onto the sensor membrane <NUM> as a gel and curing. For example, the thin layer <NUM> may include silicone. In some embodiments, the thin layer <NUM> includes silicon oxide, oxide, metal, metal oxide (such as tantalum pentoxide (Ta<NUM>O<NUM>), titanium, or a titanium oxide), or any other coating commonly used in the processing of microelectromechanical systems (MEMS) or semiconductors. The thin layer <NUM> can have a thickness of about <NUM> micron. In some embodiments, the thin layer <NUM> has a thickness greater than <NUM> micron. For example, the thin layer <NUM> may have a thickness of <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns, > <NUM> microns, or any suitable thickness. In certain embodiments, the thin layer <NUM> has a thickness of less than <NUM> micron. For example, the thin layer <NUM> may have a thickness of <NUM> microns, <NUM> microns, <NUM> microns, <NUM> microns. < <NUM> microns, or anv suitable thickness. In certain embodiments, the protection layer could be several layers to serve as different protection barriers. For example, one layer could be a very thin layer of a metal oxide (such as tantalum pentoxide (Ta20s), titanium, or a titanium oxide), silicon oxide, oxide, metal, or any other coating commonly used in the processing of MEMS or semiconductors, and another layer could be an additional polymer protection layer such as a layer of silicone polymer. The very thin layer of metal/metal oxide could be, for example, about <NUM> nanometers thick. In other embodiments, more than two layers may be preferred to improve adhesion capabilities between the different layers (i.e. silicon, metal, polymer) and provide the desired protection capability. Depending on the stiffness or drift behavior of the materials, different thicknesses might be considered. For materials with stronger negative influence on the signal (e.g., damping, drift, nonlinearity), thin layers will be preferred. For soft protective layers, thicker layers might be preferred to improve the protective function.

<FIG> is a partial side cross-sectional view of another sensing assembly <NUM> including an additional protective layer covering the sensor membrane. The sensing assembly <NUM> includes a sensor <NUM>, a transmission fiber <NUM>, a jacket <NUM>, glue <NUM>, a sensor visor <NUM>, and a layer <NUM>. The sensor <NUM> includes a sensor head <NUM>, a sensor membrane <NUM>, and a temperature compensation portion <NUM>. The sensor head <NUM> includes a cavity <NUM>. The transmission fiber <NUM> ends in the proximal portion of the sensor head <NUM> to which it is coupled with low loss. The cavity <NUM> in combination with the sensor membrane <NUM> forms a Fabry-Perot resonator. To allow for the resonant measuring principle, both sides of the cavity <NUM> are manufactured to reflect light. As far as detection of the signal has to be made possible, on one side, preferably the transmission fiber <NUM> side, partial reflection is realized, and preferably on the sensor membrane <NUM> side, full reflection is realized. The temperature compensation portion <NUM> is configured to prevent drift in sensed signals due to temperature fluctuations. The temperature compensation portion <NUM> is smaller in size than the sensor membrane <NUM> and may include silicon dioxide. The jacket <NUM> is positioned about the transmission fiber <NUM> and may include a glass ring. The transmission fiber <NUM> is coupled to the sensor head <NUM> by the glue <NUM>, which may be ultraviolet-curing epoxy. The sensor visor <NUM> is configured to extend beyond a distal end of the sensor membrane <NUM>.

The layer <NUM> is encapsulated over and covers the sensor membrane <NUM>, and protects the sensor membrane <NUM> from damage due to the flow of blood over the sensor membrane <NUM>. For example, the layer <NUM> can prevent the sensor membrane <NUM> from being dissolved by a chemical reaction with the patient's blood. Additionally, the layer <NUM> impedes biological deposits from forming directly on the sensor membrane <NUM>. In embodiments where the sensing assembly <NUM> is a pressure sensor, the layer <NUM> transmits pressure from the blood to the sensor membrane <NUM> so that the blood pressure can be sensed. The layer <NUM> may include a material capable of being deposited onto the sensor membrane <NUM> as a gel and curing. For example, the layer <NUM> may include silicone. The layer <NUM> has a thickness of about <NUM>. In some embodiments, the layer <NUM> has a thickness of about <NUM> or greater. For example, the layer <NUM> may have a thickness of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>. <NUM>, <NUM>, <NUM>, > <NUM>, or any suitable thickness. In certain embodiments, the layer <NUM> has a thickness of about <NUM> or less. For example, the layer <NUM> may have a thickness of <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <<NUM>, or any suitable thickness. The sensor membrane <NUM> is recessed further relative to the sensor visor <NUM> in the proximal direction than the sensor membrane <NUM> in the embodiment of <FIG> by a distance approximately equal to the thickness of the layer <NUM>. Recessing the sensor membrane <NUM> further below the sensor visor <NUM> can provide improved protection from damage due to the flow of blood over the sensor membrane <NUM>. The sensing assembly <NUM> can include any number of additional protective layers deposited over the sensor membrane <NUM>, for example, <NUM>, <NUM>, or <NUM> protective layers.

The sensing assembly <NUM> can also include a gel (e.g., silicone gel) or other material proximal to the sensor membrane <NUM> and can partially or fully fill the cavity <NUM> to ensure that there is no blood ingress. This can prevent thrombosis in this area of the sensing assembly <NUM> and can also prevent damage to the sensing assembly <NUM> as blood could potentially damage the transmission fiber <NUM> and interfere with its connection with the sensor head <NUM>.

<FIG> is a flow diagram of an exemplary process <NUM> for manufacturing a blood pump assembly. At Step <NUM>, a sensor (e.g., sensor <NUM> in <FIG>) is coupled to a blood pump housing component (e.g., outflow cage <NUM> of blood pump housing component <NUM> in <FIG>), such as using epoxy. Coupling the sensor to the outflow cage of the blood pump housing component may include positioning the sensor into a recess (e.g., recess <NUM> in <FIG>) in the blood pump housing component. Alternatively and as previously stated, the sensor can be coupled to a cannula assembly of the blood pump assembly. The sensor includes a sensor membrane (e.g., sensor membrane <NUM> in <FIG>) configured to deflect in response to changes in blood parameters, for example, changes in pressure, flow rate, fluid composition, or viscosity. The sensor membrane is coupled to a transmission fiber (e.g., transmission fiber <NUM> in <FIG>). The sensor includes a sensor visor (e.g., sensor visor <NUM> in <FIG>) extending over the sensor membrane. One or more protective layers (e.g., thin layer <NUM> in <FIG>) may be deposited over the sensor membrane to protect the sensor membrane from damage due to the flow of blood over the sensor membrane. For example, the protective layer can prevent the sensor membrane from being dissolved by a chemical reaction with the patient's blood. Additionally, the protective layer can impede biological deposits from forming directly on the sensor membrane. Alternatively, the protective layer may be thicker than the thin layer <NUM> in <FIG> (e.g., layer <NUM> in <FIG>) and the sensor membrane may be recessed further below the sensor visor by a distance approximately equal to the thickness of the layer. Recessing the sensor membrane further below the sensor visor can provide improved protection from damage due to the flow of blood over the sensor membrane.

At Step <NUM>, an impeller hub and blade (e.g., impeller hub <NUM> and impeller blade <NUM> of <FIG>) are coupled to a drive shaft (e.g., drive shaft <NUM> of <FIG>) such that the impeller hub and impeller blade rotate as the drive shaft rotates. Alternatively, the impeller hub, blade, and drive shaft can be monolithic and integrally formed. The outflow cage of the blood pump housing component may include one or more output ports (e.g., output ports <NUM> of <FIG>) and a plurality of struts (e.g., struts <NUM> in <FIG>) extending between the one or more output ports. The recess may be positioned distal to one of the strut of the plurality of struts in the outflow cage of the blood pump housing component.

At Step <NUM>, a cannula assembly (e.g., cannula assembly <NUM> in <FIG>) is coupled to the blood pump housing component. At Step <NUM>, the sensor visor is positioned in a visor notch of a barrier bump (e.g., visor notch <NUM> of barrier bump <NUM> in <FIG>) which protrudes from the outflow cage of the blood pump housing component. The barrier bump and the sensor visor provide advantages to the sensor in connection with permitting the sensor to traverse the torturous and calcified anatomy of the vascular system and remain operable. At Step <NUM>, a blood inflow cage (e.g., blood inflow cage <NUM> of <FIG>) is coupled to the cannula assembly. At Step <NUM>, a flexible atraumatic extension (e.g., flexible atraumatic extension <NUM> of <FIG>) is coupled to the blood inflow cage.

<FIG> is a flow diagram of an exemplary process <NUM> for detecting blood pressure. At Step <NUM>, blood is pumped through a cannula assembly (e.g., cannula assembly <NUM> in <FIG>) using an impeller blade (e.g., impeller blade <NUM> in <FIG>) positioned at least in part in the blood pump housing component (e.g., blood pump housing component <NUM> in <FIG>). The impeller blade is coupled to an impeller hub (e.g., impeller hub <NUM> of <FIG>) rotated by a drive shaft coupled to the impeller hub. The blood pump housing component includes an outflow cage (e.g., outflow cage <NUM> in <FIG>). Pumping blood may include pumping blood through one or more output ports (e.g., output port <NUM> in <FIG>) in the blood pump housing component.

At Step <NUM>, blood pressure of the pumped blood is detected using an optical pressure sensor (e.g., sensor <NUM> in <FIG>) coupled to the outflow cage of the blood pump housing component. The optical pressure sensor includes a sensor membrane (e.g., sensor membrane <NUM> in <FIG>) configured to deflect in response to a change in pressure on the sensor membrane. The sensor membrane may include a glass/silicon material. The sensor membrane may be facing toward a distal end of the blood pump assembly. The sensor membrane may have a thickness as previously described. The optical pressure sensor includes a sensor visor (e.g., sensor visor <NUM> in <FIG>) extending a distance in the distal direction beyond the sensor membrane so as to form a shroud portion overhanging the sensor membrane. The outflow cage of the blood pump housing component may include a barrier bump (e.g., barrier bump <NUM> in <FIG>) protruding from the outflow cage of the blood pump housing component. The barrier bump and the sensor visor provide advantages to the optical pressure sensor in connection with permitting the optical pressure sensor to traverse the torturous and calcified anatomy of the vascular system and remain operable. The barrier bump may protect the sensor membrane by deflecting upcoming obstacles presented by calcification within the vascular system or changes in direction of the sensor. The sensor visor may protect the sensor membrane by preventing soft obstructions, such as valve leaves on a blood pump introducer, from contacting and damaging the sensor membrane. Obstacles deflected by the baraer bump may ride over the sensor visor, thereby preventing the obstacles from contacting and/or damaging the sensor membrane. The barrier bump may be positioned in front of a recess (e.g., recess <NUM> in <FIG>). The recess may be between the barrier bump and the sensor membrane.

A protective layer (e.g., thin layer <NUM> in <FIG>) or layers may be deposited over the sensor membrane to protect the sensor membrane from damage due to the flow of blood over the sensor membrane. For example, the layers can prevent the sensor membrane from being dissolved by a chemical or biological reaction with the patient's blood. Additionally, the layer can impede biological deposits from forming directly on the sensor membrane. Alternatively, the protective layer may be thicker than the thin layer <NUM> in <FIG> (e.g., layer <NUM> in <FIG>) and the sensor membrane may be recessed further below the sensor visor by a distance approximately equal to the thickness of the layer. Recessing the sensor membrane below the sensor visor can provide improved protection from damage due to the flow of blood over the sensor membrane. In the case of an optical sensor, the sensor is coupled directly or indirectly to an optical fiber (e.g., transmission fiber <NUM> in <FIG>).

At Step <NUM>, the sensor membrane is washed by blood flowing through a blood aperture (e.g., blood aperture <NUM> of <FIG>) extending through the outflow cage of the blood pump housing component. Washing the sensor membrane prevents buildup or clotting of blood on the surface of the sensor membrane.

At Step <NUM>, blood flowing through the blood aperture is deflected using the sensor visor which can extend from the optical pressure sensor over the sensor membrane and into a visor notch in the barrier bump. The blood can also exit through the blood aperture and a new volume of blood can enter the blood aperture.

Additional embodiments include the embodiments listed below. The invention, however, comprises all technical features defined in claim <NUM>.

In a first additional embodiment (not claimed), a blood pump assembly comprises: 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 being coupled to a transmission fiber; wherein the blood pump assembly includes a shield that covers at least a portion of the sensor membrane to protect the sensor from physical damage.

The blood pump assembly of A1, wherein the shield comprises a barrier bump positioned distal relative to the sensor membrane.

The blood pump assembly of A2, further comprising a sensor visor to protect the sensor from physical damage, the sensor visor extending in a distal direction beyond the sensor membrane.

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

The blood pump assembly of A4, further comprising a cap that covers the visor notch.

The blood pump assembly of any of A3-A5, wherein the sensor visor is attached to the barrier bump by adhesive or welding.

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.

The blood pump assembly of any of A3-A7, wherein the sensor membrane is recessed in a proximal direction relative to the sensor visor.

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 relative to the sensor membrane for washing the sensor membrane with blood (claimed).

In a second additional embodiment (not claimed), a blood pump assembly comprises: a blood pump housing component; and 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 being coupled to a transmission fiber, wherein the blood pump assembly includes a passive protective mechanism for protecting the sensor from damage when the blood pump assembly is inserted into a patient.

The blood pump assembly of A10, wherein the passive protective mechanism includes a barrier positioned distal to the sensor membrane.

The blood pump assembly of A11, wherein the barrier protrudes from the blood pump housing component.

The blood pump assembly of any of A11-A12, wherein the barrier is composed of the same material as the blood pump housing component.

The blood pump assembly of any of A11-A13, wherein the barrier has a smooth outer surface which contacts the blood.

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

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 a distal end of the blood pump assembly.

The blood pump assembly of A16, wherein the one or more protective layers include a single layer deposited over the sensor membrane and formed of a material capable of being deposited as a gel and curing.

The blood pump assembly of A16 or A17, wherein the one or more protective layers comprise a material capable of preventing the sensor membrane from being dissolved by a chemical or biological reaction with blood.

The blood pump assembly of any of A16-A18, wherein the one or more protective layers comprise a layer of silicone.

The blood pump assembly of any of A16-A19, wherein the one or more protective layers comprise a metal oxide.

The blood pump assembly of any of A10-A20, wherein the sensor membrane has a thickness of <NUM> microns or less.

The blood pump assembly of any of A10-A21, wherein the sensor is positioned in a sensor bed in the blood pump housing component.

The blood pump assembly of any of A10-<NUM>, wherein the sensor is an optical sensor that transmits optical signals.

The blood pump assembly of any of A10-A23, wherein the blood pump housing component has a substantially cylindrical and elongate shape.

In a third additional embodiment (not claimed), a blood pump assembly comprises: a drive unit; an impeller blade rotatably coupled to the drive unit; a blood pump housing component including a peripheral wall extending about a rotational axis of the impeller blade: a cannula assembly coupled to the blood pump housing component; and 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, the sensor membrane being coupled to a transmission fiber; wherein the blood pump assembly includes a shield that covers at least a portion of the sensor membrane.

The blood pump assembly of Bl, wherein the shield includes a barrier bump positioned distal relative to the sensor membrane and a sensor visor overhanging the sensor membrane.

The blood pump assembly of B2, wherein the sensor visor extends to the barrier bump.

The blood pump assembly of B3, wherein the sensor visor extends into a visor notch in the barrier bump.

The blood pump assembly of B4, wherein a cap covers the visor notch.

The blood pump assembly of any of B2-B5, wherein the sensor visor is attached to the barrier bump by adhesive.

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

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

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 relative to the sensor membrane for washing the sensor membrane.

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

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

In a fourth additional embodiment (not claimed), a blood pump assembly comprises: a drive unit; an impeller blade rotatably coupled to the drive unit; a blood pump housing component including a peripheral wall extending about a rotational axis of the impeller blade; a cannula assembly coupled to the blood pump housing component; and 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, the sensor membrane being coupled to a transmission fiber; wherein the blood pump assembly includes a shield configured as a passive protective mechanism positioned distal relative to the sensor membrane.

The blood pump assembly of B12, wherein the passive protective mechanism positioned distal relative to the sensor membrane includes a barrier positioned distal relative to the sensor membrane.

The blood pump assembly of B13, wherein the barrier positioned distal relative to the sensor membrane includes a barrier bump positioned distal relative to the sensor membrane.

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

The blood pump assembly of any of B14-B15, wherein the barrier bump is composed of the same material as the blood pump housing component.

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

The blood pump assembly of any of B14-B17, wherein the barrier bump is composed of stainless steel.

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

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.

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.

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

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

The blood pump assembly of B23, wherein the barrier positioned such that the sensor membrane is between the barrier and the peripheral wall of the blood pump housing component includes a sensor visor overhanging the sensor membrane.

The blood pump assembly of B24, wherein the sensor visor is stainless steel.

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

The blood pump assembly of B24-B26, wherein the sensor includes a biocompatible material.

The blood pump assembly of B24-B27, wherein the sensor visor is coated by a biocompatible material.

In a fifth additional embodiment (not claimed), a blood pump assembly comprises: a drive unit; an impeller blade rotatablv coupled to the drive unit; a blood pump housing component including a peripheral wall extending about a rotational axis of the impeller blade, a cannula assembly coupled to the blood pump housing component; and 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, the sensor membrane being coupled to a transmission fiber; wherein the blood pump assembly includes a shield configured as a passive protective mechanism covering a surface of the sensor membrane.

The blood pump assembly of B29, wherein the passive protective mechanism covering the surface of the sensor membrane includes a barrier covering the surface of the sensor membrane.

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.

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 the surface of the sensor membrane is deposited on the surface of the sensor membrane facing toward a distal end of the blood pump assembly.

The blood pump assembly of any of B31-B32, wherein the protective layer has a thickness approximately equal to <NUM> or greater.

The blood pump assembly of any of claims B31-B32, wherein the protective layer has a thickness approximately equal to <NUM> or greater.

The blood pump assembly of any of B31-B34, wherein the protective layer comprises a material capable of being deposited as a gel and hardening.

The blood pump assembly of any of B31-B35, wherein the protective layer comprises a material capable of preventing the sensor membrane from being dissolved by a chemical reaction with blood.

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

In a sixth additional embodiment (not claimed), a blood pump assembly comprises: a drive unit; an impeller blade rotatably coupled to the drive unit; a blood pump housing component including a peripheral wall extending about a rotational axis of the impeller blade; a cannula assembly coupled to the blood pump housing component; and 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, the sensor membrane being coupled to a transmission fiber; wherein the blood pump assembly includes a shield configured as one or more active protective mechanisms for the sensor membrane.

The blood pump assembly of B38, wherein the one or more active protective mechanisms include a mechanism for washing the sensor membrane.

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

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

The blood pump assembly of B41, wherein the peripheral wall of the blood pump housing component includes a recess positioned distal relative to the sensor membrane.

The blood pump assembly of B42, wherein the recess is wider than the sensor.

The blood pump assembly of B43, wherein the blood aperture is positioned in the recess.

The blood pump assembly of any of B41-B44, wherein the blood aperture permits blood flowing through the cannula assembly and into the blood pump housing component to exit the blood pump housing component and wash the sensor membrane.

The blood pump assembly of any of B1-B45, wherein the peripheral wall of the blood pump housing component includes one or more blood exhaust windows.

The blood pump assembly of any of B1-B46, wherein the peripheral wall of the blood pump housing component includes an transmission fiber bed recessed within the peripheral wall of the blood pump housing component, the transmission fiber of the sensor positioned in the transmission fiber bed.

The blood pump assembly of any of B1-B47, wherein the sensor includes a glass ring positioned about the transmission fiber.

The blood pump assembly of any of B1-B48, wherein the sensor membrane has a thickness of <NUM> microns or less.

The blood pump assembly of any of B1-B48, wherein the sensor membrane has a thickness of <NUM> microns or less.

The blood pump assembly of any of B1-B50, wherein the sensor is positioned in a sensor bed in the peripheral wall of the blood pump housing component.

The blood pump assembly of B46, wherein the blood pump housing component includes a plurality of struts extending between the blood exhaust windows.

The blood pump assembly of B52, wherein the transmission fiber bed is positioned in a strut of the plurality of struts of the blood pump housing component.

The blood pump assembly of B53, wherein the transmission fiber is coupled to the strut of the plurality of struts by an epoxy.

The blood pump assembly of any of B1-B54, wherein the impeller blade is positioned at least in part in the blood pump housing component.

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 the blood pump housing component is coupled to the cannula assembly at a second end opposite the first end.

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

The blood pump assembly of B57, wherein the blood inflow cage includes a plurality of inlet openings.

The blood pump assembly of any of B57-B58, further comprising a flexi ble atraumatic extension coupled to the blood inflow cage.

In a seventh additional embodiment (not claimed), a method of manufacturing a blood pump assembly comprises: 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 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 a rotational axis of the impeller blade; and coupling a cannula assembly to the blood pump housing component.

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

The method of any of B60-B61, wherein coupling the sensor to the peripheral wall of the blood pump housing component includes affixing the sensor to the peripheral wall of the blood pump housing component.

The method of any of B60-B62, wherein coupling the sensor to the peripheral wall of the blood pump housing component includes positioning the sensor into a blood recess in the peripheral wall of the blood pump housing component.

The method of B63, wherein the blood pump housing component includes a plurality of blood exhaust windows and a plurality of struts extending between the blood exhaust windows and wherein the blood recess is positioned in a strut of the plurality of struts in the blood pump housing component.

The method of any of B60-B64, further comprising coupling a blood inflow cage to the cannula assembly.

The method of B65, further comprising coupling a flexible atraumatic extension to the blood inflow cage.

The method of any of B60-B66, further comprising depositing a protective layer over a surface of the sensor membrane.

The method of any of B60-B66, further comprising depositing a protective layer over a surface of the sensor membrane and recessing the sensor membrane further below the sensor visor by a distance approximately equal to the thickness of the protective layer.

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

The blood pump assembly of any of B1-B69, wherein the sensor transmits its sensed signals optically.

The blood pump assembly of B70, wherein the transmission fiber is an optical fiber.

The blood pump assembly of any of B1-<NUM>, wherein the drive unit is driven by an external motor.

In an eighth additional embodiment (not claimed), a method of detecting blood pressure comprises: pumping blood through a cannula assembly coupled to a blood pump housing component, the blood pumped by an impeller blade positioned at least in part in the blood pump housing component, the impeller blade rotated by a drive unit coupled to the impeller blade, the blood pump housing component including a peripheral wall extending about a rotational axis of the impeller blade; and detecting a blood pressure of the blood pumped using 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 a change in pressure on the sensor membrane, the sensor membrane coupled to an optical fiber, and the optical pressure sensor including a sensor visor overhanging the sensor membrane.

The method of B73, wherein pumping blood includes pumping blood through one or more blood exhaust windows in the blood pump housing component.

The method of any of B73-B74, further comprising washing the sensor membrane using blood flow through a blood aperture extending through the peripheral wall of the blood pump housing component, the blood aperture positioned in a blood recess positioned in front of the sensor membrane of the optical pressure sensor.

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 positioned in front of the blood recess, such that the blood recess is between the barrier bump and the sensor membrane.

The method of B76, further comprising deflecting the blood flowing through the blood aperture using a sensor visor extending from the optical pressure sensor over the sensor membrane and into a visor notch in the barrier bump.

The method of any of B73-B77, wherein the sensor membrane includes a glass material.

The method of any of B73-B78, wherein the sensor membrane faces toward a distal end of the pump.

The method of any of B73-B79, wherein the sensor membrane is less than <NUM> microns thick.

The method of any of B73-B80, wherein a protective layer is deposited over a surface of the sensor membrane.

The method of any of B73-B80, wherein a protective layer is deposited over a 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.

Claim 1:
A blood pump assembly (<NUM>) comprising:
a blood pump housing component (<NUM>);
at least one input port (<NUM>) and at least one outlet port (<NUM>); and
a sensor (<NUM>) coupled to the blood pump housing component (<NUM>), the sensor (<NUM>) including a sensor membrane (<NUM>) configured to deflect in response to a change in a blood parameter, the sensor (<NUM>) being coupled to a transmission fiber (<NUM>);
wherein the blood pump assembly (<NUM>) includes a shield that covers at least a portion of the sensor membrane (<NUM>) to protect the sensor (<NUM>) from physical damage, characterized in that the shield includes a blood aperture (<NUM>) extending through the blood pump housing component (<NUM>) and positioned distal relative to the sensor membrane (<NUM>) for washing the sensor membrane (<NUM>) with blood.