Intravascular blood pump with outflow hose

Abstract

The intravascular blood pump (200) includes a pump housing (211) having an intake port (214) and an outlet port (216). A relatively short intake cannula (226) can draw blood through the intake port (230) and deliver the blood to the intake port (214) of the pump housing (211). The intake cannula (226) is relatively short to prevent excessive hydraulic loss. An outflow hose (234) is connected to the outlet port (216) of the pump housing (211) so as to convey blood exiting the outlet port (216) downstream through the outflow hose (234) to an exhaust port (238), for example, into the aorta or other blood vessel (205). Despite the short intake cannula (226), the outflow hose (234) separates the intake port (230) longitudinally sufficiently from the exhaust port (238) so that the intake port (230) and the exhaust port (238) remain on opposite sides of the heart valve even if the intravascular heart pump (200) accidentally moves longitudinally. TIFF2023510873000002.tif127159

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 62 / 961,017, entitled "Intravascular Blood Pump with Outflow Hose," filed January 14, 2020, the entire contents of which are incorporated herein by reference for all purposes.

[0002] Technical Field The present invention relates to an intravascular blood pump, and more particularly to an intravascular blood pump having an outlet hose that increases the longitudinal spacing between the blood intake port and the blood outlet port. [Background technology]

[0003] Related technologies An intravascular blood pump is a pump that can be advanced through a patient's blood circulatory system, i.e., through veins and / or arteries, to a location in the patient's heart or elsewhere within the patient's circulatory system. For example, an intravascular blood pump can be inserted via a catheter and positioned to span a heart valve. The intravascular blood pump is typically located at the end of the catheter. Once in place, the pump pumps blood through the circulatory system and thus can be used to temporarily reduce the workload of the patient's heart, such as to allow the heart to recover after a heart attack.

[0004] Known types of intravascular blood pumps include axial flow blood pumps, centrifugal or radial flow blood pumps, and mixed flow blood pumps, in which blood flow is driven by a combination of axial and radial forces. Blood pumps typically include a pump housing defining an inlet port and an outlet port. An intake cannula extends from the inlet port of the pump housing to a blood intake port at the distal end of the intake cannula. An impeller is disposed within the pump housing. The impeller may be driven by an electric motor also disposed within the pump housing. Alternatively, the impeller may be driven by an external motor via a flexible drive shaft that extends through a catheter to the outside of the patient's body. In either case, rotation of the impeller draws blood into the blood intake port, flows through the cannula, and is expelled from an outlet port of the pump housing.

[0005] Some intravascular blood pumps have a diametrically expandable pump housing and a diametrically expandable impeller, while other blood pumps have a non-expandable, i.e., fixed-diameter pump housing and a non-expandable, i.e., fixed-diameter impeller. Expandable-housing blood pumps are inserted into a patient while the blood pump and impeller are in a compressed (non-expanded) state, and then, after the blood pump is properly positioned, the pump housing and impeller are expanded in diameter. The compressed state allows expandable-housing blood pumps to typically be introduced and guided into a patient's vasculature more easily than fixed-diameter blood pumps.

[0006] Generally, the impeller of an expandable housing blood pump increases in diameter when expanded, and therefore can operate at lower rotational speeds than fixed-diameter blood pumps to pump equivalent flow rates. These lower speeds allow expandable housing pumps to be driven by flexible drive shafts and external motors. In contrast, fixed-diameter blood pumps currently must be driven by motors located near the impeller. Such internal motors are powered by electrical wires that extend through a catheter to an external power source. Because internal motors must be smaller and rotate faster than external motors, they are more complex and expensive. Nevertheless, most intravascular blood pumps in use today are non-expandable blood pumps with internal motors.

[0007] An exemplary expandable housing blood pump is described in U.S. Pat. No. 8,439,859, and an exemplary fixed diameter blood pump is described in U.S. Patent Application Publication No. 2019 / 0046702, the entire contents of each of which are incorporated herein by reference for all purposes.

[0008] When placed in an operating position, the blood intake port of an intravascular blood pump is typically upstream of the blood outlet port. When the blood pump is placed across a heart valve, the leaflets of the heart valve open and close over the blood pump; that is, the leaflets close around the blood pump. Thus, in use, the pump body extends across the heart valve, and in the closed position, the leaflets physically capture and seal around the body of the blood pump.

[0009] Catheters and blood pumps can accidentally move for a variety of reasons, including patient movement and cardiac activity. However, for blood pumps positioned across a heart valve, it is important that the blood intake port remain on one side of the heart valve and the blood outlet port remain on the other side of the heart valve. If the blood pump were to move along the longitudinal axis of the catheter so that both the blood intake and outlet ports were on the same side of the heart valve, the efficiency of the blood pump would be seriously adversely affected. Even relatively small movements of the blood pump that move the blood outlet port into the heart valve are problematic because the heart valve would then close on the blood outlet port. Even if the blood pump is still effective and capable of pumping blood, the pumped blood would be hemolyzed.

[0010] Increasing the length of the intake cannula further separates the blood intake port from the blood outlet port, thus allowing for more longitudinal movement of the blood pump, thereby reducing the risk of the adverse effects described above. However, a longer intake cannula results in increased hydraulic loss. To mitigate this increased hydraulic loss, the intake portion of the cannula can be configured to expand in diameter after the blood pump is deployed. Such an expandable intake cannula is described in U.S. Patent Application Publication No. 2004 / 044266, the entire contents of which are incorporated herein by reference for all purposes. However, such an expandable intake cannula increases the complexity and cost of the blood pump and its insertion process. Furthermore, as noted above, most vascular blood pumps in use today are non-expandable blood pumps. Therefore, there is a need for a fixed-diameter intravascular blood pump that is more resistant to longitudinal movement than prior art blood pumps. Therefore, a technical challenge is to increase the resistance of fixed-diameter intravascular blood pumps to longitudinal movement without increasing the length of the intake cannula. [Prior art documents] [Patent documents]

[0011] [Patent Document 1] U.S. Patent No. 8,439,859 [Patent Document 2] U.S. Patent Application Publication No. 2004 / 044266 Summary of the Invention

[0012] Overview of Aspects One aspect of the present invention provides an intravascular blood pump 200 including a catheter 204, a pump housing 211, an impeller 212, and an outflow hose 234. The catheter 204 is configured to be inserted into a blood vessel 205. The blood vessel 205 defines an interior volume 207 through which blood flows in a blood flow direction 208. The pump housing 211 is attached to the catheter 204. The pump housing 211 defines an inlet port 214 and an outlet port 216. The impeller 212 is disposed within the pump housing 211. The impeller 212 is configured to pump blood from the inlet port 214 to the outlet port 216 when it rotates. The outflow hose 234 is in fluid communication with the outlet port 216 of the pump housing 211. The outflow hose 234 defines an exhaust port 238. The exhaust port 238 is longitudinally spaced 240 downstream relative to the direction of blood flow 208 from the outlet port 216 of the pump housing 211. The exhaust port 238 is in fluid communication with the interior volume 207 of the blood vessel 205.

[0013] Optionally, in any embodiment, outflow hose 234 may be coaxial with catheter 204 .

[0014] Optionally, in any embodiment, the effective internal cross-sectional area 502 of the outflow hose 234 may be at least as large as the effective internal cross-sectional area 700 of the intake port 214 of the pump housing 211 .

[0015] Optionally, in any embodiment, the effective inner cross-sectional area 502 of the outflow hose 234 may be greater than the effective inner cross-sectional area 700 of the intake port 214 of the pump housing 211 .

[0016] Optionally, in any embodiment, the effective internal cross-sectional area 502 of the outflow hose 234 may be at least twice the effective internal cross-sectional area 700 of the intake port 214 of the pump housing 211 .

[0017] Optionally, in any embodiment, the effective inner cross-sectional area 502 of the outflow hose 234 may be larger than the effective inner cross-sectional area 502 of the pump housing 211 .

[0018] Optionally, in any embodiment, the exhaust port 238 of the outflow hose 234 may be longitudinally spaced 240 downstream relative to the direction of blood flow 208 by at least about 50 mm from the outlet port 216 of the pump housing 211 .

[0019] Optionally, in any embodiment, the exhaust port 238 of the outflow hose 234 may be longitudinally spaced 240 downstream relative to the direction of blood flow 208 by at least about 80 mm from the outlet port 216 of the pump housing 211 .

[0020] Optionally, in any embodiment, the exhaust port 238 of the outflow hose 234 may be longitudinally spaced 240 downstream relative to the direction of blood flow 208 by at least about 100 mm from the outlet port 216 of the pump housing 211 .

[0021] Optionally, in any embodiment, the outlet port 238 of the outflow hose 234 may be longitudinally spaced 240 approximately 50-150 mm downstream relative to the direction of blood flow 208 from the outlet port 216 of the pump housing 211 .

[0022] Optionally, in any embodiment, the outlet port 238 of the outflow hose 234 may be longitudinally spaced 240 approximately 80-120 mm downstream relative to the direction of blood flow 208 from the outlet port 216 of the pump housing 211 .

[0023] Optionally, in any embodiment, outflow hose 234 may be at least about 50 mm in length.

[0024] Optionally, in any embodiment, outflow hose 234 may be at least about 80 mm in length.

[0025] Optionally, in any embodiment, outflow hose 234 may be at least about 100 mm in length.

[0026] Optionally, in any embodiment, outflow hose 234 may be from about 50 mm to about 150 mm in length.

[0027] Optionally, in any embodiment, outflow hose 234 may be from about 80 mm to about 120 mm in length.

[0028] Optionally, in any embodiment, outflow hose 234 may be radially collapsible 600 and / or radially expandable 500. Outflow hose 234 may be configured to increase in radius by at least about 25% from an initial radius in response to blood pressure generated by impeller 212 when impeller 212 pumps blood. Outflow hose 234 may be configured to at least partially collapse 600 due to a lack of blood pressure when impeller 212 is not pumping blood.

[0029] Optionally, any embodiment may include a first pressure sensor 300 located on the pump housing 211 outside of the outflow hose 234 .

[0030] Optionally, any embodiment may include a second pressure sensor 302 located inside the outlet hose 234 .

[0031] Optionally, in any embodiment, the discharge port 216 of the pump housing 211 may include a plurality of openings defined circumferentially around the pump housing 211 .

[0032] Optionally, in any embodiment, the discharge port 216 of the pump housing 211 may include multiple openings. The multiple openings may be defined along multiple rows 1600-1604. The rows (1600-1604) may be spaced longitudinally along the outlet hose 234.

[0033] Optionally, in any embodiment, the intake port 214 of the pump housing 211 may include a cannula 226. The cannula 226 may extend longitudinally in an upstream direction relative to the blood flow direction 208 to an intake port 228 defined by the cannula 226. The intake port 228 may be in fluid communication with the interior volume 207 of the blood vessel 205.

[0034] Optionally, in any embodiment, the portion 400 of the cannula 226 that defines the intake port 228 may be radially expandable to a diameter greater than the outer diameter of the pump housing 211 .

[0035] Optionally, in any embodiment, the cannula (226) may define an intake port (230), and the outlet port 238 of the outflow hose 234 may be longitudinally spaced 236 from the intake port 230 of the cannula 226 by at least about 90 mm, or at least about 100 mm, in a downstream direction relative to the blood flow direction 208.

[0036] Optionally, any embodiment may include an electric motor 220 disposed within the pump housing 211. The electric motor 220 may be mechanically coupled to the impeller 212 and configured to rotate the impeller 212.

[0037] Optionally, any embodiment may include a drive shaft 224 disposed within catheter 204. Drive shaft 224 may be mechanically coupled to impeller 212 and configured to transfer rotational energy to impeller 212 from a motor external to intravascular blood pump 200. [Brief explanation of the drawings]

[0038] The foregoing summary and the present invention will be more fully understood from the following detailed description of specific embodiments taken in conjunction with the drawings. However, the scope of the disclosure is not limited to the specific embodiments disclosed herein.

[0039] [Figure 1] FIG. 1 shows a conventional intravascular blood pump placed in the left ventricle of a human heart according to the prior art. [Figure 2] FIG. 1 illustrates an intravascular blood pump according to one embodiment of the present invention positioned in the left ventricle of a human heart. [Figure 3] Figure 3a is an enlarged view of a portion of Figure 2. Figure 3b is an enlarged view of a portion of Figure 2 according to an alternative embodiment of the present invention. [Figure 4] 3 shows an enlarged distal end portion of the intake cannula of the intravascular blood pump of FIG. 2 according to an alternative embodiment of the present invention. [Figure 5] FIG. 5 is a cross-sectional view of the outflow hose and catheter of the intravascular blood pump of FIGS. 2-4, with the outflow hose inflated, according to one embodiment of the present invention. [Figure 6] FIG. 6 is a cross-sectional view of the outflow hose and catheter of FIG. 5 with the outflow hose in a collapsed state, according to one embodiment of the present invention. [Figure 7] FIG. 5 is a cross-sectional view of a pump housing and an intake port of the pump housing of the intravascular blood pump of FIGS. 2-4, according to one embodiment of the present invention. [Figure 8] FIG. 4 is a perspective view of an end portion of the intravascular blood pump of FIGS. 2-3, according to one embodiment of the present invention. [Figure 9] FIG. 4 is a cross-sectional view of an end portion of the intravascular blood pump of FIGS. 2-3, according to one embodiment of the present invention. [Figure 10] FIG. 4 is a longitudinal cross-sectional view of an end portion of the intravascular blood pump of FIGS. 2-3, according to one embodiment of the present invention. [Figure 11] FIG. 4 is a perspective view of an end portion of the intravascular blood pump of FIGS. 2-3, according to another embodiment of the present invention. [Figure 12] FIG. 4 is a cross-sectional view of an end portion of the intravascular blood pump of FIGS. 2-3, according to another embodiment of the present invention. [Figure 13] FIG. 4 is a perspective view of an end portion of the intravascular blood pump of FIGS. 2-3, according to yet another embodiment of the present invention. [Figure 14] FIG. 4 is a cross-sectional view of an end portion of the intravascular blood pump of FIGS. 2-3, according to yet another embodiment of the present invention. [Figure 15] FIG. 10 illustrates an intravascular blood pump including an alternative intake cannula positioned in the left ventricle of a human heart, according to another aspect of the present invention. [Figure 16] FIG. 2 is a perspective view (rotated 90 degrees about the longitudinal axis) of an intravascular blood pump according to an alternative embodiment of the present invention. [Figure 17] FIG. 1 is a side view (rotated 90 degrees about the longitudinal axis) of an intravascular blood pump according to an alternative embodiment of the present invention. [Figure 18] FIG. 1 is a side view (rotated 90 degrees about the longitudinal axis) of an intravascular blood pump according to an alternative embodiment of the present invention. [Figure 19] 19A-19C illustrate exemplary blood flow from the exhaust port from the intravascular blood pump of FIGS. 16-18, as simulated by a computer program. DETAILED DESCRIPTION OF THE INVENTION

[0040] Detailed Description of Specific Embodiments Aspects of the present invention provide fixed-diameter (non-expandable) intravascular blood pumps that are resistant to longitudinal movement along their respective catheters without lengthening the intake cannula or suffering a resulting increase in hydraulic loss. Intravascular blood pumps according to the present invention reduce the risk of accidentally displacing both the blood intake port and the blood outlet port on the same side of the heart valve. Furthermore, intravascular blood pumps according to the present invention reduce the risk of accidentally displacing the blood outlet port in its position within the heart valve. Each such intravascular blood pump includes an outflow hose. The outflow hose provides a blood outlet port that is longitudinally separated downstream from the pump outlet port. The outflow hose longitudinally separates the blood outlet port from the blood intake port by more than prior art blood pumps, without lengthening the intake cannula. In some aspects, the intake cannula is shorter than prior art.

[0041] Prior Art Intravascular Blood Pumps 1 shows a conventional fixed diameter (non-expandable) intravascular blood pump 100 positioned in the left ventricle 102 of a human patient's heart 104. The blood pump 100 is positioned at one end of a catheter 106 for inserting the blood pump 100 into the left ventricle 102, such as via the aorta 108. The blood pump 100 is positioned to extend through an aortic valve 110, the leaflets of which close around the blood pump 100.

[0042] Blood pump 100 includes a pump housing 112 that houses an impeller and a motor (not visible). Pump housing 112 defines an axial pump housing inlet port 114 and a radial pump housing outlet port 116. Radial pump housing outlet port 116 may include a plurality of openings (windows) defined circumferentially around pump housing 112. The impeller draws blood into pump housing 112 through axial pump housing inlet port 114 and withdraws blood from radial pump housing outlet port 116, as indicated by arrows.

[0043] Blood pump 100 includes an inlet cannula 118 having one end attached in fluid communication to axial pump housing inlet port 114. The opposite end of inlet cannula 118 defines an intake port 120. Cannula intake port 120 may include a plurality of openings (windows) defined circumferentially around intake cannula 118. Thus, blood is drawn from left ventricle 102, through cannula intake port 120, into inlet cannula 118, and delivered to axial pump housing inlet port 114.

[0044] The intake port 120 and the pump housing outlet port 116 are separated by a distance 122 so that, when the blood pump 100 is positioned within the heart 104, the intake port 120 and the pump housing outlet port 116 are positioned on opposite sides of the aortic valve 110, making it less likely that expected longitudinal movement of the blood pump 100 will cause the intake port 120 and the pump housing outlet port 116 to move to the same side of the aortic valve 110 or move the pump housing outlet port 116 into the aortic valve 110. The distance 122 requires a relatively long inlet cannula 118, which, as noted above, results in relatively high hydraulic losses, particularly because the inlet cannula 116 is connected to the suction (suction) end of the pump housing 112.

[0045] Both pumps do not actually mechanically force fluid into the pump, but rather push or expel fluid from the pump. Discharging fluid from the pump creates a partial vacuum within the pump. Ambient pressure of the fluid at the pump's intake (suction) port, such as the pressure of blood in the left ventricle 102, forces the fluid into the pump. The effectiveness of this pushing depends, at least in part, on the pressure difference between the ambient pressure and the partial vacuum. Without sufficient inlet pressure, the pump will not operate properly. The available net positive suction head (NPSHa) must be sufficient to meet the pump's net positive suction head requirement (NPSHr); otherwise, the pump may experience cavitation. The blood pressure in the left ventricle 102 is relatively low. Therefore, the blood pump 100 is particularly sensitive to friction losses caused by the inlet cannula 118.

[0046] Intravascular blood pump with outflow hose Figure 2 illustrates a fixed diameter (non-expandable) intravascular blood pump 200 according to one embodiment of the present invention. The intravascular blood pump 200 is shown positioned in the left ventricle 102 of a human patient's heart 104. Figures 3a and 3b are enlarged views of portion 202 of Figure 2 according to two respective embodiments.

[0047] Blood pump 200 includes a catheter 204 for inserting blood pump 200 into left ventricle 102 via aorta 108, which includes descending aorta 205 and aortic arch 206. Catheter 204 is configured to be inserted into a blood vessel, such as aorta 206, that defines an interior volume 207 through which blood flows in a direction of blood flow, e.g., as indicated by arrow 208. Catheter 204 extends to a controller (not shown), such as the Automatic Impella Controller (“AIC”) available from Abiomed, Inc. of Danvers, Massachusetts 01923. The controller provides a user interface for controlling and monitoring intravascular blood pump 200.

[0048] As used herein, the term "distal" refers to a direction or position along the catheter 204 away from the controller or user, and the term "proximal" refers to a direction or position along the catheter 204 toward the controller or user.

[0049] During insertion, the intravascular blood pump 200 is positioned to extend through the aortic valve 110, as shown in FIG. 2, although in other applications, the intravascular blood pump 200 may be positioned elsewhere in the patient's vasculature, not necessarily within the heart. Additionally, while FIG. 2 shows the intravascular blood pump 200 inserted such that the blood flow direction 208 is away from the distal end of the catheter 204, in other applications, the intravascular blood pump 200 may be inserted such that the blood flow direction 208 is toward the distal end of the catheter 204. For example, the intravascular blood pump 200 may be inserted from the left atrium 209 through the mitral valve 210 into the left ventricle 102. In the application shown in FIG. 2, the leaflets of the aortic valve 110 close around the blood pump 200.

[0050] Intravascular blood pump 200 includes a pump housing 211 (best shown in FIGS. 3a and 3b) that houses an impeller (not visible, but indicated by reference numeral 212). Pump housing 211 defines an axial pump housing inlet port 214 and a radial pump housing outlet port 216. Radial pump housing outlet port 216 may include a plurality of openings (windows) defined circumferentially around pump housing 211. As impeller 212 rotates, it is configured to pump blood from pump housing inlet port 214 to pump housing outlet port 216. Impeller 212 draws blood into pump housing 212 through axial pump housing inlet port 214 and withdraws blood from radial pump housing outlet port 216, as indicated by arrow 218.

[0051] In some embodiments, an electric motor (not visible, but indicated by reference numeral 220) is disposed within or adjacent to pump housing 211. Motor 220 is mechanically coupled to impeller 212 and configured to rotate impeller 212. Electrical wires 222 extend from motor 220 through catheter 204 to a controller to provide power to motor 220. In other embodiments, impeller 212 is driven by a flexible drive shaft 224 (only a portion of which is shown in phantom) that extends through catheter 204 to an external motor (not shown), such as a motor in the controller.

[0052] Intake port 214 of pump housing 211 includes intake cannula 226. One end of intake cannula 226 is attached in fluid communication to axial pump housing inlet port 214. Cannula 226 extends longitudinally in an upstream direction relative to blood flow direction 208. The opposite end of intake cannula 226 defines intake port 228. Cannula intake port 228 may include a plurality of openings (windows), represented by openings 230, defined circumferentially around intake cannula 226.

[0053] Intake cannula 226 is relatively short, thereby causing relatively little hydraulic loss. In some embodiments, intake cannula 226 is about 5-60 mm long, or about 10-25 mm long. Experiments and / or simulations have shown that such a relatively short intake cannula 226 can increase blood flow by about 0.2 L / min or more compared to a conventional, otherwise equivalent intravascular blood pump. Alternatively, intake cannula 226 of other suitable lengths may be used.

[0054] Optionally, as shown in Figure 4, enlarged distal end portion 400 of intake cannula 226 has larger inner and outer diameters than the remainder of intake cannula 226 and larger than pump housing 211. Enlarged distal end portion 400 of intake cannula 226 may define a plurality of openings 402 circumferentially around intake cannula 226, for example, as the spacing between adjacent struts represented by struts 404.

[0055] 2, blood is drawn from the left ventricle 102 through multiple openings 230 into cannula intake port 228 and delivered through intake cannula 226 to axial pump housing inlet port 214. As discussed in more detail herein, intake cannula 226 is much shorter than the much longer intake cannula 118 of the prior art intravascular heart pump 100 shown in FIG. 1, and therefore incurs much less hydraulic loss.

[0056] At its distal end, intravascular blood pump 200 includes a soft pigtail or J-tip 232 configured to facilitate insertion of intravascular blood pump 200 into patient's heart 104 without harming surrounding tissue. Soft tip 232 also helps keep soft tissue away from blood flow inlet opening 230 of intake cannula 226. Soft tip 232 may be, for example, about 10-60 mm in length, or about 20-35 mm in length.

[0057] Outlet hose As previously described, intake cannula 226, intake port 228, and radial pump housing outlet port 216 are all located within left ventricle 102. However, intravascular blood pump 200 also includes an outflow hose 234 that extends from radial pump housing outlet port 216 through aortic valve 110 and into aorta 108. Outflow hose 234 separates intake port 230 and the location where blood exits intravascular blood pump 200 by a distance 236 that is at least as large as in the prior art, without requiring a long intake cannula 118 (FIG. 1).

[0058] Outlet hose 234 may be substantially cylindrical and coaxial with catheter 204, as shown in cross section in Figure 5. Alternatively, outflow hose 234 may have another suitable cross-sectional shape (not shown). Outlet hose 234 may be positioned to surround catheter 204 over the length of outflow hose 234, as shown in Figure 5. Alternatively (not shown), outflow hose 234 may run parallel to, but not coaxial with, catheter 204.

[0059] Outflow hose 234 is in fluid communication with outlet port 216 of pump housing 211. The proximal end 237 of outflow hose 234 should be mechanically attached to catheter 204 to prevent proximal end 237 from sliding along catheter 204 into left ventricle 102. Similarly, the distal end 304 of outflow hose 234 should be mechanically attached to cannula 204, pump housing 211, or intake cannula 226.

[0060] As shown in Figure 3a, the distal end 304 of the outflow hose 234 may be distal to the distal-most portion of the opening of the outlet port 216. However, this configuration may result in an undesirable blood recirculation zone 306 between the distal end 304 of the outflow hose 234 and the distal-most portion of the opening of the outlet port 216. To avoid this potential problem, as shown in Figure 3b, the distal-most end 304 of the outflow hose 234 should be attached to the cannula 204, pump housing 211, or intake cannula 226 as close as possible to the distal-most portion of the opening of the outlet port 216.

[0061] The outer diameter of the portion of outflow hose 234 near its proximal end 237 may taper radially inward along the proximal, i.e., downstream, direction to facilitate insertion and withdrawal of intravascular blood pump 200. However, in other embodiments, the outer diameter of the proximal portion of outflow hose 234 is not tapered.

[0062] Outlet hose 234 defines an exhaust port 238 near its proximal end 237, which may include multiple openings defined circumferentially around outflow hose 234. Exhaust port 238 is in fluid communication with the interior volume 207 of the blood vessel (in this case, the aorta 205).

[0063] The apertures may all be defined along a single circumferential row around the outflow hose 234, as shown in FIG. 3. Alternatively, the apertures may be defined along two or more circumferential rows, as shown in FIGS. 16-19. The pump housing 211 and the discharge port 216 of the pump housing 211 are shown in phantom in FIG. 16. While the embodiment shown in FIGS. 16-19 has three rows of apertures 1600, 1602, and 1604, other embodiments may have other numbers of rows, such as two, four, five, six, or more rows of apertures. The rows 1600-1604 may be spaced longitudinally along the outflow hose 234, as illustrated by the longitudinal spacing 1606. Each row 1600-1604 may include one or more apertures.

[0064] The embodiment shown in FIGS. 16-19 has two apertures per row 1600-1604, as shown most clearly in FIGS. 17-18. However, other embodiments may have other numbers of apertures per row 1600-1604, such as one, three, four, five, six, or more apertures per row. While it is possible for all rows 1600-1604 to have the same number of apertures, this is not necessarily the case. The apertures in each row 1600-1604 may be offset by an angle 1606, such as about 90° or another suitable angle, from the apertures in the adjacent row(s) 1600-1604. The multiple rows 1600-1604 of apertures and the angular offset 1606 help reduce vibrations in the intravascular blood pump 200 and stabilize the intravascular blood pump 200. 19 shows an exemplary spiral blood flow 1900 from the exhaust port 238 as a result of multiple rows of apertures 1600-1603 and angular offset 1606, as simulated by a computer program. Advantageously, the multiple rows of apertures 1600-1603 and angular offset 1606 may prevent or limit backflow of blood during diastole.

[0065] Exhaust port 238 is longitudinally spaced downstream relative to blood flow direction 208 from outlet port 216 of pump housing 211. This longitudinal spacing is indicated by distance 240. In various embodiments, distance 240 may be at least about 50 mm, at least about 80 mm, at least about 100 mm, about 50-150 mm, about 80-120 mm, or another distance suitable for reducing the risk of exhaust port 238 and intake port 230 accidentally moving to the same side of aortic valve 110 and / or the risk of exhaust port 238 accidentally moving into aortic valve 110, even if intravascular blood pump 200 moves longitudinally an expected distance further into left ventricle 102.

[0066] Distance 240 may be selected based on various considerations, such as the size of the patient's expected heart chambers and / or heart valves, taking into account the patient's age and / or cardiac condition, the size of pump housing 211 and / or the size of other components of intravascular heart pump 200, and the desired length of intake cannula 226 to achieve a desired low hydraulic loss in intake cannula 226. However, placing exhaust port 238 too high in aorta 108 may result in undesirable blood flow patterns, such as retrograde flow during cardiac ejection.

[0067] In some embodiments, the outflow hose 234 has a length of at least about 50 mm, at least about 80 mm, about 100 mm, at least about 100 mm, about 50 to 150 mm, about 80 to 120 mm, or another length suitable to reduce the risk of the exhaust port 238 and the intake port 230 accidentally moving to the same side of the aortic valve 110 and / or to reduce the risk of the exhaust port 238 accidentally moving into the aortic valve 110, even if the intravascular blood pump 200 moves further longitudinally into the left ventricle 102 an expected distance.

[0068] The length of the outflow hose 234 may be selected based on various considerations, such as the expected size of the patient's heart, taking into account the patient's age and / or cardiac condition, the size of the pump housing 211 and / or the size of other components of the intravascular heart pump 200, and the desired length of the intake cannula 226 to achieve the desired low hydraulic loss in the intake cannula 226.

[0069] Exhaust port 238 is longitudinally spaced downstream relative to blood flow direction 208 from intake port 230 of intake cannula 226. This longitudinal spacing is indicated by distance 236. In some embodiments, distance 236 is at least about 90 mm. In other embodiments, distance 236 is at least about 100 mm. In yet other embodiments, distance 236 is another distance suitable for reducing the risk of exhaust port 238 and intake port 230 accidentally moving to the same side of aortic valve 110 and / or for reducing the risk of exhaust port 238 accidentally moving into aortic valve 110, even if intravascular blood pump 200 moves longitudinally an expected distance further into left ventricle 102.

[0070] The distance 236 may be selected based on various considerations, such as the expected dimensions of the patient's heart chambers and / or heart valves, taking into account the patient's age and / or cardiac condition, the dimensions of the pump housing 211 and / or the dimensions of other components of the intravascular heart pump 200, and the desired length of the intake cannula 226 to achieve the desired low hydraulic loss in the intake cannula 226.

[0071] Some prior art expandable intravascular heart pumps (not shown) have impellers located relatively close to their intake ports. Such intravascular heart pumps advantageously experience relatively little hydraulic loss in the inlet cannula due to the proximity of the impeller to the intake port, i.e., the relatively short inlet cannula. However, in this configuration, the intake port is located relatively close to the distal end of the catheter, near the pigtail or J-tip. This location of the intake port is relatively close to the inner wall of the heart chamber. Therefore, there is a relatively high risk that the rotating impeller will draw cardiac tissue, such as trabeculae, into the intake port, potentially damaging the cardiac tissue. Ideally, the impeller 212 should be spaced at least about 2 cm from the intake port 230 to prevent the impeller 212 from damaging the trabeculae it has drawn in.

[0072] On the other hand, prior art intravascular heart pumps 100 position the impeller relatively far from the intake port 114, thereby advantageously reducing the risk of damage to cardiac tissue. However, as noted above, this placement of the impeller requires a relatively long inlet cannula 118 with the attendant relatively high hydraulic losses.

[0073] Aspects of the present invention solve this dilemma, providing the benefits of both low risk or damage to cardiac tissue and low hydraulic loss.

[0074] Outlet hose 234 may be made of a suitable biocompatible material, such as a suitable polymer, such as polyurethane, polyamide, nylon, silicone, or the like. In some embodiments, outflow hose 234 is radially collapsible, as indicated by arrow 600 in FIG. 6 , and / or radially expandable, as indicated by arrow 500 in FIG. 5 . In such embodiments, outflow hose 234 may be configured to increase in radius by, for example, at least about 25%, or at least about 50%, or at least about 75%, or at least about 100%, or at least about 133%, or at least about 150% from its initial radius in response to blood pressure generated by impeller 212 as it pumps blood. Essentially, the blood pressure causes outflow hose 234 to expand. FIG. 5 shows outflow hose 234 and catheter 204 with outflow hose 234 in an expanded state. In some embodiments, outflow hose 234 is elastically radially collapsible and / or elastically radially expandable. In other embodiments, the expandable and / or collapsible nature of outflow hose 234 need not be elastic. In other words, outflow hose 234 may be "floppy" when not inflated, and outflow hose 234 may essentially fold or wrinkle to collapse and unfold to expand. As used herein, the term "inflating" does not necessarily require stretching the material of outflow hose 234, and "collapse" does not necessarily require the opposite, stretching the material of outflow hose 234.

[0075] Outlet hose 234 may be configured to radially collapse when impeller 212 is not pumping blood due to a lack of blood pressure, as shown in FIG. 6 , which illustrates outflow hose 234 and catheter 204 with outflow hose 234 in a collapsed state. Such a radially expandable outflow hose 234 facilitates insertion and removal of intravascular blood pump 200 by reducing the outer diameter of outflow hose 234 during insertion and removal. For example, in some embodiments, catheter 204 may have a size of approximately 9 Fr, and outflow hose 234 may have essentially the same size (9 Fr) or slightly larger when collapsed or unexpanded, while outflow hose 234 may have a size of approximately 18-21 Fr when expanded.

[0076] Outflow hose 234 has an effective inner cross-sectional area 502 ( FIG. 5 ) that is equal to the inner cross-sectional area of ​​outflow hose 234 minus the outer cross-sectional area of ​​catheter 204 and any other structure(s) inside outflow hose 234 that obstruct blood flow between pump housing outlet port 216 and exhaust port 238. In the embodiment shown in FIG. 5 , effective inner cross-sectional area 502 is toroidal in shape. In other embodiments, effective inner cross-sectional area 502 may have another shape.

[0077] The effective inner cross-sectional area 502 of the outflow hose 234 should be at least as large as the inner cross-sectional area 700 (FIG. 7) of the intake port 214 of the pump housing 211. Preferably, the effective inner cross-sectional area 502 of the outflow hose 234 is larger than the inner cross-sectional area of ​​the intake port 214 of the pump housing 211. In some embodiments, the effective inner cross-sectional area 502 of the outflow hose 234 is at least twice the inner cross-sectional area of ​​the intake port 214 of the pump housing 211. The effective inner cross-sectional area 502 of the outflow hose 234 must be larger than the inner cross-sectional area of ​​the pump housing 211.

[0078] The effective inner cross-sectional area 502 of the outflow hose 234 should be at least as large as the inner cross-sectional area of ​​the intake cannula 226. Preferably, the effective inner cross-sectional area 502 of the outflow hose 234 is larger than the inner cross-sectional area of ​​the intake cannula 226. In some embodiments, the effective inner cross-sectional area 502 of the outflow hose 234 is at least twice the inner cross-sectional area of ​​the intake cannula 226.

[0079] Such an outflow hose 234 can provide an increase in blood flow of up to about 0.2 L / min over a conventional, otherwise equivalent, intravascular blood pump. For a 14F intravascular blood pump 200, i.e., an intravascular blood pump 200 having a maximum outer diameter of approximately 5 mm, the total achievable blood flow under normal conditions is about 4 L / min.

[0080] Pressure Sensor The flow rate of intravascular blood pump 200 can be estimated based on the dimensions of intravascular blood pump 200 and the difference between pressure measurements taken at two or more locations. To facilitate measuring these pressures, a first pressure sensor 300 (FIG. 3) may be located on pump housing 211 upstream of the distal end of outflow hose 234. Alternatively, the first pressure sensor may be located elsewhere along intake cannula 226, such as at or near the proximal end of intake cannula 226, adjacent to pump housing inlet port 214, or proximate opening 230 of intake port 228, as shown at 242 (FIG. 2), so long as first pressure sensor 300 contacts the blood in left ventricle 102 directly, i.e., not through the interior of intravascular blood pump 200. In other words, first pressure sensor 300 should be external to intravascular blood pump 200. The first pressure sensor 300 should be placed in a location that is unlikely to escape the left ventricle 102 under any possible usage scenario while the intravascular blood pump 200 is operating, so that the first pressure sensor 300 can reliably report the pressure within the left ventricle 102. The locations described herein meet this criterion.

[0081] In the prior art, an intravascular blood pump 100 ( FIG. 1 ) including an intake cannula 118 attached to a pump housing 112 is typically positioned such that the pump housing 112 straddles a heart valve 110. Because the intravascular blood pump 100 may move longitudinally during use, the intake cannula 118, rather than the pump housing 112, may end up located within the heart valve 110. Therefore, it is not appropriate for such prior art intravascular blood pumps 100 to include a pressure sensor near the pump housing 112. Such a pressure sensor may move away from the left ventricle 102 and, therefore, may provide erroneous pressure measurements. Therefore, in prior art intravascular blood pumps 100, the pressure sensor is typically positioned at the distal end of the intake cannula 118. Aspects of the present invention do not suffer from this drawback.

[0082] A second pressure sensor 302 (FIG. 3) may be disposed inside the outflow hose 234 to measure the pressure of the outflow blood generated by the intravascular blood pump 200. The pressure inside the outflow hose 234 is substantially the same as the pressure in the aorta 205 because blood flows from the outflow hose 234 into the aorta 205 without substantial pressure loss. The outflow hose 234 and the exhaust port 238 include a plurality of openings defined circumferentially around the outflow hose 234 and are configured to provide substantially unimpeded blood flow therethrough so as not to cause a substantial pressure drop. Alternatively, the second pressure sensor may be disposed on the catheter 204, inside or outside the outflow hose 234. However, it is preferable to position the second pressure sensor 302 on the motor housing 211 for ease of connection to wires extending through the catheter 204 to the controller. These wires transmit signals from the first pressure sensor 300 and the second pressure sensor 302 to the controller.

[0083] The controller may be configured to estimate the flow rate of the intravascular blood pump 200 from the blood pressure measurements provided by the first pressure sensor 300 and the second pressure sensor 302, i.e., from the blood pressure in the left ventricle 102 and the blood pressure in the outflow hose 234.

[0084] Blood flow inlet opening As described above, the enlarged distal end portion 400 of the intake cannula 226 can have an enlarged diameter section 400 (FIG. 4) defining a plurality of openings 402. FIGS. 8-10 are perspective, cross-sectional, and longitudinal cross-sectional views, respectively, of the enlarged diameter section 400 of the intake cannula 226, according to one embodiment of the present invention. FIGS. 8-10 show the enlarged diameter section 400 of the intake cannula 226 under normal intravascular blood pump 200 operating conditions, including typical blood pressure and a flow rate of approximately 4 liters per minute (l / min).

[0085] The plurality of openings 402 are defined by a framework structure, such as a cage 802, that includes struts 804. Each strut 804 separates a pair of adjacent openings 402 from one another. In this embodiment, the struts 804 extend substantially axially, parallel to the longitudinal axis 806 of the intake cannula 226. However, in other embodiments, the struts 804 may extend radially or helically, or the struts 804 may form any other suitable shape that defines openings 402 therebetween. In the embodiment shown in FIGS. 8-10, five struts 804 form the cage 802. However, other embodiments may include more or fewer struts 804. For example, some embodiments (not shown) include three, four, six, seven, eight, or more struts 804.

[0086] Optionally, in any embodiment, struts 804 may be interconnected by members, represented by members 808 shown in phantom, that extend between pairs of struts 804. Members 808 are configured to strengthen cage 802 to resist crushing and other deformations.

[0087] A sleeve 810 covers a portion of the enlarged distal end portion 400 of the intake cannula 226 to reduce the possibility of tissue being drawn into the opening 402. The sleeve 810 overlaps a portion of the intake cannula 226 and extends over a proximal portion of the cage 802.

[0088] Sleeve 810 may have a funnel shape to increase the blood flow rate of intravascular blood pump 200. The funnel shape has a cross-sectional diameter that decreases in a direction from distal end 812 of sleeve 810 to proximal end 814 of sleeve 810. Sleeve 810 should have a monotonically narrowing cross-sectional diameter in a direction from distal end 812 to proximal end 814. In particular, the cross-sectional diameter of distal end 812 of sleeve 810 should not decrease in an upstream direction.

[0089] 9, the cross-sectional shape of sleeve 810 may be substantially circular, at least when blood is not being pumped, and sleeve 810 may be supported by struts 804 of cage 802. That is, the inner wall of sleeve 810 may contact struts 804 and be held in a fixed radially outward position.

[0090] However, in some embodiments (not shown), the inner diameter of sleeve 810 may be larger than the outer diameter of a circle circumscribing struts 804. Under certain conditions, sleeve 810 may be held radially open by blood flowing into sleeve 810. In this case, the flowing blood exerts pressure on inner surface 900 of sleeve 810, maintaining the funnel shape of sleeve 810 and thus preventing collapse of sleeve 810 during operation of intravascular blood pump 200. Optionally, or alternatively, sleeve 810 may be made of a suitable material strong enough to prevent collapse of sleeve 810, or sleeve 810 may be reinforced by a suitable structure, as described herein.

[0091] In some embodiments, or under certain circumstances, sleeve 810 may have a cross-sectional shape other than substantially circular, as shown, for example, in Figures 11-12. Sleeve 810 may fit closely around struts 804. For example, if cage 802 includes five struts 804, sleeve 810 may have a pentagonal cross-sectional shape, as shown in Figure 12.

[0092] As a result of the inward pressure, indicated by arrows 1400 ( FIG. 14 ), exerted by blood at the distal end 812 of the sleeve 810, the sleeve 810 may deflect inward from the struts 804 into the openings 402. However, the sleeve 810, struts 804, etc. should be configured to limit deflection radially inward to no more than about 0.2 mm on each side so as not to adversely affect blood flow under expected pressures and flow rates. In particular, the sleeve 810 should be sufficiently rigid to prevent the sleeve 810 from being sucked into the openings 402, which could block the openings 402.

[0093] Expandable cage Optionally, in any embodiment, cage 802, as well as sleeve 810, and optionally intake cannula 226, may be diametrically expandable. That is, these components may be configured such that they assume a compressed configuration having a relatively small diameter prior to insertion into the operating position, and can be diametrically expanded to a larger diameter after insertion into the operating position. In particular, in the compressed configuration (not shown), the outer diameter of enlarged diameter portion 400 may be substantially the same as or smaller than the outer diameter of the remainder of intake cannula 226 to facilitate delivery of intravascular blood pump 200 through the introducer sheath. Then, after intravascular blood pump 200 is positioned for operation, enlarged diameter portion 400 may be expanded to an outer diameter larger than the outer diameter of the remainder of intake cannula 226, as shown in the figure.

[0094] Sleeve 810 may have a structure that provides sufficient radial stiffness to prevent sleeve 810 from collapsing during normal operation of intravascular blood pump 200, for example, a structure including a membrane of a suitable material such as polyurethane, although additional reinforcing structure attached to or embedded in sleeve 810 may be provided. The reinforcing structure provides radial stiffness during operation of intravascular blood pump 200, but at the same time provides expansion and compression characteristics, allowing the components to resiliently (a) compress to facilitate insertion of intravascular blood pump 200, (b) expand once the blood pump is in place, and (c) subsequently compress again to facilitate removal of intravascular blood pump 200 from the patient. In some embodiments, intake cannula 266 is expandable to an outer diameter greater than the outer diameter of pump housing 211 over most or all of its axial length. The expandable cage 802 and sleeve 810 may be made using the information described in the aforementioned U.S. Patent No. 8,439,859 and / or U.S. Patent Application Publication No. 2019 / 0046702.

[0095] Such an expandable cage 802 and sleeve 810 can provide an increase in blood flow of up to about 0.2 L / min over an otherwise equivalent conventional intravascular blood pump without increasing the risk of hemolysis. An intake cannula 226 that is expandable over most of its axial length can provide an additional increase in blood flow of up to about 0.2 L / min over an otherwise equivalent conventional intravascular blood pump 100. An expandable pump housing such as that described in the aforementioned U.S. Patent No. 8,439,859 can be used as the intake cannula 226 of the intravascular blood pump 200 described herein.

[0096] Alternative uptake cannula FIG. 15 illustrates another embodiment of a blood pump 200 in which only the configuration of the intake cannula 226 differs from the embodiment described with reference to FIGS. 2-3 . In the embodiment shown in FIG. 15 , the enlarged diameter portion 400 of the intake cannula 226 extends the entire length of the intake cannula 226. Thus, the opening 402 is located at the distal end portion of the cage structure 802. However, the remainder of the cage structure 802 is covered by a sleeve 810, and the proximal end of the cage structure 802 is attached to the intake port 214 of the pump housing 211. The intake cannula 226 can be manufactured in the same manner as the pump housing of the expandable intravascular blood pumps discussed herein. For example, the cage structure 802 can be manufactured using well-known laser cutting techniques. Advantageously, the pump housing 211 and the cage structure 802 of the intake cannula 226 can be manufactured from a single tube so that they form an integral part.

[0097] The various intake cannulas 266 and openings 402 described herein prevent, or at least reduce the risk of, soft tissue, such as a filament, within the left ventricle 102 being drawn into the openings 402. Additionally, the intake cannulas 226 described herein prevent, or at least reduce the risk of, the openings 402 being pulled out of the left ventricle 102 while the intravascular blood pump 200 is in use, even as a result of slight longitudinal movement of the intravascular blood pump 200.

[0098] Although the present invention has been described through the above exemplary embodiments, modifications and variations of the exemplary embodiments can be made without departing from the inventive concept disclosed herein. For example, although specific parameter values ​​such as dimensions and materials may be described in connection with the disclosed embodiments within the scope of the present invention, the values ​​of all parameters can be varied over a wide range to suit various applications. Unless otherwise indicated in the context or understood by one of ordinary skill in the art, terms such as "about" mean within ±20%.

[0099] As used herein, including the claims, the term "and / or" when used in connection with a list of items means one or more of the items in the list, i.e., at least one of the items in the list, but not necessarily all of the items in the list. As used herein, including the claims, the term "or" when used in connection with a list of items means one or more of the items in the list, i.e., at least one of the items in the list, but not necessarily all of the items in the list. "Or" does not mean "exclusive or."

[0100] Aspects of the disclosure, or portions thereof, may be combined in ways not described above and / or not expressly claimed. In addition, the embodiments disclosed herein may suitably be practiced in the absence of any element not specifically disclosed herein. Thus, the present invention should not be considered limited to the disclosed embodiments.

[0101] As used herein, numerical terms such as "first," "second," and "third" are used to distinguish one pressure sensor or other element from another, and are not intended to indicate a particular order or total number of pressure sensors or other elements in a particular embodiment. Thus, for example, a given embodiment may include only a second pressure sensor and a third pressure sensor.

Claims

1. a catheter (204) configured for insertion into a blood vessel (205) defining an interior volume (207) through which blood flows in a blood flow direction (208); a pump housing (211) attached to the catheter (204) and defining an intake port (214) and an outlet port (216); an impeller (212) disposed within the pump housing (211) and configured to pump blood from the intake port (214) to the outlet port (216) when the impeller rotates; a cannula (226) having a proximal end and a distal end, the proximal end of the cannula (226) attached in fluid communication with the intake port (214) of the pump housing (211), the cannula (226) defining an intake port (228) distal to the intake port (214) of the pump housing (211); an outflow hose (234) in fluid communication with the discharge port (216) of the pump housing (211), the outflow hose (234) being longitudinally spaced (240) from the discharge port (216) of the pump housing (211) in a downstream direction relative to the blood flow direction (208), the outflow hose (234) defining an exhaust port (238) in fluid communication with the interior volume (207) of the blood vessel (205); an intravascular blood pump (200), including:

2. 2. The intravascular blood pump (200) of claim 1, wherein the outflow hose (234) is coaxial with the catheter (204), the outflow hose (234) has a proximal end and a distal end, the proximal end of the outflow hose (234) is attached to the catheter (204), the outflow hose (234) surrounds a portion of the catheter (204) and the outlet port (216) of the pump housing (211), and the intake port (228) of the cannula (226) is outside and distal to the distal end of the outflow hose (234).

3. 2. The intravascular blood pump (200) of claim 1, wherein the effective inner cross-sectional area (502) of the outflow hose (234) is at least as large as the effective inner cross-sectional area (700) of the intake port (214) of the pump housing (211).

4. 2. The intravascular blood pump (200) of claim 1, wherein an effective internal cross-sectional area (502) of the outflow hose (234) is greater than an effective internal cross-sectional area (700) of the intake port (214) of the pump housing (211).

5. 2. The intravascular blood pump (200) of claim 1, wherein the effective inner cross-sectional area (502) of the outflow hose (234) is at least twice the effective inner cross-sectional area (700) of the intake port (214) of the pump housing (211).

6. 2. The intravascular blood pump (200) of claim 1, wherein the effective inner cross-sectional area (502) of the outflow hose (234) is greater than the effective inner cross-sectional area (502) of the pump housing (211).

7. 2. The intravascular blood pump (200) of claim 1, wherein the exhaust port (238) of the outflow hose (234) is longitudinally spaced (240) downstream relative to the blood flow direction (208) from the outlet port (216) of the pump housing (211) by at least about 50 mm.

8. 2. The intravascular blood pump (200) of claim 1, wherein the exhaust port (238) of the outflow hose (234) is longitudinally spaced (240) downstream relative to the blood flow direction (208) from the outlet port (216) of the pump housing (211) by at least about 80 mm.

9. 2. The intravascular blood pump (200) of claim 1, wherein the exhaust port (238) of the outflow hose (234) is longitudinally spaced (240) downstream relative to the blood flow direction (208) from the outlet port (216) of the pump housing (211) by at least about 100 mm.

10. 2. The intravascular blood pump (200) of claim 1, wherein the exhaust port (238) of the outflow hose (234) is longitudinally spaced (240) downstream relative to the blood flow direction (208) from the outlet port (216) of the pump housing (211) by approximately 50 to 150 mm.

11. 2. The intravascular blood pump (200) of claim 1, wherein the exhaust port (238) of the outflow hose (234) is longitudinally spaced (240) downstream relative to the blood flow direction (208) by approximately 80 to 120 mm from the outlet port (216) of the pump housing (211).

12. 10. The intravascular blood pump (200) of claim 1, wherein the outflow hose (234) is at least about 50 mm in length.

13. 10. The intravascular blood pump (200) of claim 1, wherein the outflow hose (234) is at least about 80 mm in length.

14. 10. The intravascular blood pump (200) of claim 1, wherein the outflow hose (234) is at least about 100 mm in length.

15. The intravascular blood pump (200) of any preceding claim, wherein the outflow hose (234) is between about 50 mm and about 150 mm in length.

16. The intravascular blood pump (200) of any preceding claim, wherein the outflow hose (234) is between about 80 mm and about 120 mm in length.

17. 2. The intravascular blood pump of claim 1, wherein the outflow hose is radially collapsible and / or radially expandable, configured to increase in radius from an initial radius by at least about 25% in response to blood pressure generated by the impeller when the impeller pumps blood, and to at least partially collapse due to insufficient blood pressure when the impeller does not pump blood.

18. 10. The intravascular blood pump (200) of claim 1, further comprising a first pressure sensor (300) disposed on the pump housing (211) outside the outflow hose (234).

19. 20. The intravascular blood pump (200) of claim 18, further comprising a second pressure sensor (302) disposed inside the outflow hose (234).

20. An intravascular blood pump (200) according to any one of claims 1 to 19, wherein the discharge port (216) of the pump housing (211) comprises a plurality of openings defined circumferentially around the pump housing (211).

21. 20. An intravascular blood pump (200) according to any one of claims 1 to 19, wherein the exhaust port (238) of the outflow hose (234) comprises a plurality of openings defined along a plurality of rows (1600-1604), the rows (1600-1604) being spaced longitudinally along the outflow hose (234).

22. 20. An intravascular blood pump (200) according to any one of claims 1 to 19, wherein the intake port (214) of the pump housing (211) includes the cannula (226), which extends longitudinally in an upstream direction relative to the blood flow direction (208) to the intake port (228) defined by the cannula (226), and the intake port (228) is in fluid communication with the internal volume (207) of the blood vessel (205).

23. 23. The intravascular blood pump (200) of claim 22, wherein a portion (400) of the cannula (226) defining the intake port (228) is radially expandable to a diameter greater than the outer diameter of the pump housing (211).

24. An intravascular blood pump (200) as described in any one of claims 1 to 19, wherein the discharge port (238) of the outflow hose (234) is longitudinally spaced (236) at least approximately 90 mm downstream from the intake port (230) of the cannula (226) relative to the blood flow direction (208).

25. an electric motor (220) disposed within the pump housing (211) and mechanically coupled to the impeller (212) and configured to rotate the impeller (212); The intravascular blood pump (200) of any one of claims 1 to 19, further comprising:

26. a drive shaft (224) disposed within the catheter (204) and mechanically coupled to the impeller (212) and configured to transfer rotational energy to the impeller (212) from a motor external to the intravascular blood pump (200); The intravascular blood pump (200) of any one of claims 1 to 19, further comprising:

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