Patent Publication Number: US-2023149695-A1

Title: Device housing features to facilitate damage free guidewire translations

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application claims priority to Provisional Application No. 63/280,345, filed Nov. 17, 2021, which is herein incorporated by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to percutaneous circulatory support systems. More specifically, the disclosure relates to percutaneous circulatory support devices that are delivered to a patient&#39;s heart using a guidewire. 
     BACKGROUND 
     Percutaneous circulatory support devices can provide transient support for up to approximately several weeks in patients with compromised heart function or cardiac output. Such devices are typically delivered to a patient&#39;s heart using a guidewire, whereby the circulatory support device is coupled to and moved along the guidewire through the patient&#39;s vasculature until the device is in the proper position within the heart. Generally, circulatory support devices are coupled to a guidewire by feeding the proximal end of a guidewire, the distal end of which has already been inserted into a patient&#39;s vasculature, through an opening in the device. The proximal end of the guidewire is then passed through the device and exits the device via another opening. The device is then able to be moved along the length of guidewire to insert the device into the patient&#39;s vasculature and ultimately into the patient&#39;s heart. As the guidewire passes through the openings in the device or the device moves along the guidewire, the guidewire may be damaged because the device is typically made of a metal material, while the guidewire is composed of a softer material or contains a coating. For example, the coating of the guidewire may be removed by contact between the guidewire and a surface of one of the openings. The removal of the coating material may cause health complications or negatively affect the performance of the guidewire and/or device. 
     SUMMARY 
     In an Example 1, a percutaneous circulatory support device for use with a guidewire comprises a housing including an interior lumen, an exterior surface, a blood inlet, and a blood outlet that includes a blood outlet aperture, wherein the blood outlet aperture includes a channel extending from the interior lumen to the exterior surface of the housing, the channel configured to non-marringly receive and support the guidewire. 
     In an Example 2, the percutaneous circulatory support device of Example 1, the device further comprises an impeller disposed within the interior lumen, the impeller configured to rotate relative to the housing to cause blood to flow into the blood inlet, through the interior lumen of the housing, and out of the blood outlet, and a motor operatively coupled to the impeller, the motor configured to rotatably drive the impeller. 
     In an Example 3, the percutaneous circulatory support device of Example 1 or 2, wherein the blood outlet aperture is a first blood outlet aperture, the blood outlet includes a second blood outlet aperture, and the channel extends proximally beyond the second blood outlet aperture. 
     In an Example 4, the percutaneous circulatory support device of any one of Examples 1 to 3, wherein the channel includes a first end portion which is sloped. 
     In an Example 5, the percutaneous circulatory support device of any one of Examples 1 to 3, wherein the channel includes a first end portion which is rounded. 
     In an Example 6, the percutaneous circulatory support device of any one of Examples 1 to 5, wherein the channel includes a width greater than the guidewire. 
     In an Example 7, the percutaneous circulatory support device of any one of Examples 1 to 6, wherein the channel has a length of 0.025 to 0.375 inches. 
     In an Example 8, the percutaneous circulatory support device of any one of Examples 1 to 7, wherein the channel includes a substantially flat surface to support the guidewire. 
     In an Example 9, the percutaneous circulatory support device of any one of Examples 1 to 8, wherein the channel is located on a proximal portion of the blood outlet aperture. 
     In an Example 10, the percutaneous circulatory support device of any one of Examples 1 to 9, wherein the housing further comprises a first housing portion proximal of the channel, a second housing portion distal of the channel, wherein the first housing portion has a first diameter and the second housing portion has a second diameter, the first diameter being smaller than the second diameter, and a tapered housing portion that extends between the first housing portion and the second housing portion, the channel being located within the tapered housing portion. 
     In an Example 11, the percutaneous circulatory support device of Example 10, wherein the channel includes a first side wall and a second side wall, the first and second side walls configured to form a flared opening adjacent the first housing portion. 
     In an Example 12, a method for using a percutaneous circulatory support device comprises inserting a distal end of a guidewire into the vasculature of a patient, inserting a proximal end of the guidewire into a housing of the device, the housing comprising an interior lumen, an impeller within the interior lumen, an exterior surface, and a blood outlet that includes a blood outlet aperture, the blood outlet aperture includes a channel, the channel extending from the interior lumen to the exterior surface of the housing and configured to non-marringly receive and support the guidewire, passing the proximal end of the guidewire through the interior lumen of the housing, passing the proximal end of the guidewire adjacent to the impeller, and passing the proximal end of the guidewire through the channel of the blood outlet aperture such that the guidewire extends from the interior lumen to an exterior surface of the housing. 
     In an Example 13, the method of Example 12, wherein the channel is located on a proximal portion of the blood outlet aperture. 
     In an Example 14, the method of Example 13, wherein the blood outlet aperture is a first blood outlet aperture, the housing includes a second blood outlet aperture, and the channel extends proximally beyond the second blood outlet aperture. 
     In an Example 15, the method of any one of Examples 12 to 14, further comprising moving the device along the guidewire and inserting the device into the vasculature of the patient. 
     In an Example 16, a percutaneous circulatory support device for use with a guidewire, comprises a housing comprising an interior lumen, an exterior surface, a blood inlet, and a blood outlet that includes a blood outlet aperture, an impeller disposed within the interior lumen, the impeller configured to rotate relative to the housing to cause blood to flow into the blood inlet, through the interior lumen of the housing, and out of the blood outlet; and a motor operatively coupled to the impeller, the motor configured to rotatably drive the impeller, wherein the blood outlet aperture includes a channel extending from the interior lumen to the exterior surface of the housing, the channel configured to non-marringly receive and support the guidewire. 
     In an Example 17, the percutaneous circulatory support device of Example 16, wherein the blood outlet aperture is a first blood outlet aperture, the blood outlet includes a second blood outlet aperture, and the channel extends proximally beyond the second blood outlet aperture. 
     In an Example 18, the percutaneous circulatory support device of Example 16, wherein the channel includes a first end portion which is sloped. 
     In an Example 19, the percutaneous circulatory support device of Example 16, wherein the channel includes a first end portion which is rounded. 
     In an Example 20, the percutaneous circulatory support device of Example 16, wherein the channel includes a width greater than the guidewire. 
     In an Example 21, the percutaneous circulatory support device of Example 16, wherein the channel has a length of 0.025 to 0.375 inches. 
     In an Example 22, the percutaneous circulatory support device of Example 16, wherein the channel includes a substantially flat surface to support the guidewire. 
     In an Example 23, the percutaneous circulatory support device of Example 16, wherein the channel is located on a proximal portion of the blood outlet aperture. 
     In an Example 24, the percutaneous circulatory support device of Example 16, wherein the housing further comprises a first housing portion proximal of the channel, a second housing portion distal of the channel, wherein the first housing portion has a first diameter and the second housing portion has a second diameter, the first diameter being smaller than the second diameter, and a tapered housing portion that extends between the first housing portion and the second housing portion, the channel being located within the tapered housing portion. 
     In an Example 25, the percutaneous circulatory support device of Example 24, wherein the channel includes a first side wall and a second side wall, the first and second side walls configured to form a flared opening adjacent the first housing portion. 
     In an Example 26, a percutaneous circulatory support device for use with a guidewire comprises a housing comprising an interior lumen, an exterior surface, a blood inlet, and a blood outlet that includes a first blood outlet aperture and a second blood outlet aperture, an impeller disposed within the interior lumen, the impeller configured to rotate relative to the housing to cause blood to flow into the blood inlet, through the interior lumen of the housing, and out of the first and second blood outlet apertures, and a motor operatively coupled to the impeller, the motor configured to rotatably drive the impeller, wherein the first blood outlet aperture that includes a channel configured to non-marringly receive and support the guidewire, the channel extending from the interior lumen to the exterior surface of the housing and proximally beyond the second blood outlet aperture. 
     In an Example 27, the percutaneous circulatory support system of Example 26, wherein the channel includes a first end portion which is sloped. 
     In an Example 28, the percutaneous circulatory support system of Example 26, wherein the channel includes a first end portion which is rounded. 
     In an Example 29, the percutaneous circulatory support system of Example 26, wherein the channel includes a substantially flat surface to support the guidewire. 
     In an Example 30, the percutaneous circulatory support system of Example 26, wherein the housing further comprises a first housing portion proximal of the channel, a second housing portion distal of the channel, wherein the first housing portion has a first diameter and the second housing portion has a second diameter, the first diameter being smaller than the second diameter, and a tapered housing portion that extends between the first housing portion and the second housing portion, the channel being located within the tapered housing portion. 
     In an Example 31, the percutaneous circulatory support device of Example 30, wherein the channel includes a first side wall and a second side wall, the first and second side walls configured to form a flared opening adjacent the first housing portion. 
     In an Example 32, a method for using a percutaneous circulatory support device, comprises inserting a distal end of a guidewire into the vasculature of a patient, inserting a proximal end of the guidewire into a housing of the device, the housing comprising an interior lumen, an impeller within the interior lumen, an exterior surface, and a blood outlet that includes a blood outlet aperture, the blood outlet aperture includes a channel, the channel extending from the interior lumen to the exterior surface of the housing and configured to non-marringly receive and support the guidewire, passing the proximal end of the guidewire through the interior lumen of the housing, passing the proximal end of the guidewire adjacent to the impeller, and passing the proximal end of the guidewire through the channel of the blood outlet aperture such that the guidewire extends from the interior lumen to an exterior surface of the housing. 
     In an Example 33, the method of Example 32, wherein the channel is located on a proximal portion of the blood outlet aperture. 
     In an Example 34, the method of Example 33, wherein the blood outlet aperture is a first blood outlet aperture, the housing includes a second blood outlet aperture, and the channel extends proximally beyond the second blood outlet aperture. 
     In an Example 35, the method of Example 32, further comprising moving the device along the guidewire and inserting the device into the vasculature of the patient. 
     While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a side sectional view of an illustrative mechanical circulatory support device (also referred to herein, interchangeably, as a “blood pump”), in accordance with embodiments of the subject matter disclosed herein. 
         FIG.  2 A  is a perspective view of the mechanical circulatory support device of  FIG.  1   , in accordance with embodiments of the subject matter disclosed herein. 
         FIG.  2 B  is a perspective view of an illustrative blood outlet aperture and channel, in accordance with embodiments of the subject matter disclosed herein. 
         FIG.  2 C  is a perspective view of an illustrative blood outlet aperture and channel, in accordance with embodiments of the subject matter disclosed herein. 
         FIG.  3    is a perspective view of the mechanical circulatory support device of  FIG.  1    and further illustrating a guidewire, in accordance with embodiments of the subject matter disclosed herein 
         FIG.  4    is a side sectional view of the mechanical circulatory support device of  FIG.  1    further illustrating a guidewire, introducer sheath, and blood vessel. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION 
       FIG.  1    depicts a partial side sectional view of an illustrative percutaneous circulatory support device  100  (also referred to herein, interchangeably, as a “blood pump”) in accordance with embodiments of the subject matter disclosed herein. The device  100  may form part of a percutaneous circulatory support system, together with a guidewire (shown elsewhere) and an introducer sheath (shown elsewhere). More specifically, the guidewire and the introducer sheath may facilitate percutaneously delivering the device  100  to a target location within a patient, such as within the patient&#39;s heart. Alternatively, the device  100  may be delivered to a different target location within a patient. 
     With continued reference to  FIG.  1   , the device  100  generally includes a housing  101  that includes an impeller housing  102  and a motor housing  104 . In some embodiments, the impeller housing  102  and the motor housing  104  may be integrally or monolithically constructed. In other embodiments, the impeller housing  102  and the motor housing  104  may be separate components configured to be removably or permanently coupled. In some embodiments, the blood pump  100  may lack a separate motor housing  104  and the impeller housing  102  may be coupled directly to the motor  105  described below, or the motor housing  104  may be integrally constructed with the motor  105  described below. Impeller housing  102  includes an interior lumen  102   a,  an interior surface  102   b,  and an exterior surface  102 c. Similarly, the motor housing  104  includes an interior lumen  104   a,  an interior surface  104   b,  and an exterior surface  104   c.  Center axis  103  passes longitudinally through the housing  101 . 
     The impeller housing  102  carries an impeller assembly  106  therein. The impeller assembly  106  includes an impeller shaft  108  that is rotatably supported by at least one bearing, such as a bearing  110 . The impeller assembly  106  also includes an impeller  112  that rotates relative to the impeller housing  102  to drive blood through the device  100 . More specifically, the impeller  112  causes blood to flow from a blood inlet  114  formed on the impeller housing  102 , through the impeller housing  102 , and out of a blood outlet  116  formed on the impeller housing  102 . In some embodiments and as illustrated, the impeller shaft  108  and the impeller  112  may be separate components, and in other embodiments the impeller shaft  108  and the impeller  112  may be integrated. In some embodiments and as described in more detail below, the inlet  114  and/or the outlet  116  may each include multiple apertures (see e.g.,  FIGS.  2 - 4   ). In other embodiments, the inlet  114  and/or the outlet  116  may each include a single aperture. In some embodiments and as illustrated, the inlet  114  may be formed on an end portion of the impeller housing  102  and the outlet  116  may be formed on a side portion of the impeller housing  102 . In other embodiments, the inlet  114  and/or the outlet  116  may be formed on other portions of the impeller housing  102 . In some embodiments, the impeller housing  102  may couple to a distally extending cannula (not shown), and the cannula may receive and deliver blood to the inlet  114 . 
     With continued reference to  FIG.  1   , the motor housing  104  carries a motor  105 , and the motor  105  is configured to rotatably drive the impeller  112  relative to the impeller housing  102 . In the illustrated embodiment, the motor  105  rotates a drive shaft  120 , which is coupled to a driving magnet  122 . Rotation of the driving magnet  122  causes rotation of a driven magnet  124 , which is connected to and rotates together with the impeller assembly  106 . More specifically, in embodiments incorporating the impeller shaft  108 , the impeller shaft  108  and the impeller  112  are configured to rotate with the driven magnet  124 . In other embodiments, the motor  105  may couple to the impeller assembly  106  via other components. 
     In some embodiments, a controller (not shown) may be operably coupled to the motor  105  and configured to control the motor  105 . In some embodiments, the controller may be disposed within the motor housing  104 . In other embodiments, the controller may be disposed outside of the motor housing  104  (for example, in an independent housing, etc.). In some embodiments, the controller may include multiple components, one or more of which may be disposed within the motor housing  104 . According to embodiments, the controller may be, may include, or may be included in one or more Field Programmable Gate Arrays (FPGAs), one or more Programmable Logic Devices (PLDs), one or more Complex PLDs (CPLDs), one or more custom Application Specific Integrated Circuits (ASICs), one or more dedicated processors (e.g., microprocessors), one or more Central Processing Units (CPUs), software, hardware, firmware, or any combination of these and/or other components. Although the controller is referred to herein in the singular, the controller may be implemented in multiple instances, distributed across multiple computing devices, instantiated within multiple virtual machines, and/or the like. In other embodiments, the motor  105  may be controlled in other manners. 
     With continued reference to  FIG.  1    and additional reference to  FIG.  2 A , the device  100  facilitates passage of a guidewire (shown elsewhere) through device  100  by the incorporation of a channel  126  in a blood outlet aperture  128  of the blood outlet  116 . As described above, the blood outlet  116  may include more than one aperture, for example as shown in  FIG.  2 A , the blood outlet  116  includes six blood outlet apertures  128 ,  130 ,  131 ,  132 ,  133 , and  134 . As shown in  FIG.  2 A , the blood outlet aperture  128  includes a proximal portion  136  and a distal portion  138 . In some embodiments and as shown in  FIG.  2 A , the channel  126  is located on the proximal portion  136  of the blood outlet aperture  128 . In other embodiments, the channel  126  could be located on other portions of a blood outlet aperture, for example on the distal portion  138 . As shown in  FIG.  2 A , the channel  126  extends from the blood outlet aperture  128  in a proximal direction. As also shown in  FIG.  2 A , the channel  126  extends proximally beyond each of the other blood outlet apertures  130 ,  131 ,  132 ,  133 , and  134 , thus indicating to a user that a guidewire should be passed through the blood outlet aperture  128  rather than the other blood outlet apertures  130 ,  131 ,  132 ,  133 , and  134 . Additional indicators, such as markings or lettering, may be placed near the channel  126  to indicate the proper location of the guidewire. The channel  126  has a width  140  and a length  142 . The width  140  is generally no narrower than the width of the guidewire. In some embodiments, the length  142  may vary from 0.025 inches to 0.375 inches. 
     In the embodiment in  FIGS.  2 A-C , the channel  126  includes a first end portion  144  at the distal end  146  of the channel  126 , that is, where the channel  126  meets interior surface  102   b.  Similarly, in the embodiment in  FIGS.  2 A-C , the channel  126  also includes a second end portion  148  at the proximal end  150  of the channel  126 , where the channel  126  meets the exterior surface  104   c.    FIG.  2 B  illustrates a first end portion  144   b  that has not been sloped, beveled, rounded, or otherwise mechanically altered to smooth the first end portion  144   a.  In contrast, in some embodiments, the first end portion  144  and/or second end portion  148  may be sloped, beveled, rounded, or otherwise mechanically altered to smooth the first end portion  144  and second end portion  148 . For example, as shown in  FIG.  2 C , first end portion  144   c  is rounded to smooth the first end portion  144   c.  In some embodiments, channel  126  may include fewer or additional edges or surfaces than shown in  FIGS.  2 A-C , and some or all of such edges or surfaces may be smoothed through sloping, beveling, rounding, or other mechanical alteration. As further shown in  FIGS.  2 A-C , in some embodiments, the channel  126  includes a first side wall  152  and a second side wall  154 , separated by the width  140 , both of which extend along the length  142  and flare away from each other to form a flared opening  158  adjacent to the distal end  146  of the channel  126 . The flared opening  158  may be, for example, at most  120  degrees wide. In some embodiments, the first side wall  152  and the second wall  154  may be sloped, beveled, rounded, or otherwise mechanically altered to smooth the surfaces of the first side wall  152  and a second side wall  154 . For example, as shown in  FIG.  2 C , the second wall  154   c  is rounded. In other embodiments, the first side wall  152  and the second wall  154  may remain unaltered, as shown by second wall  154 b in  FIG.  2 B . 
     As shown in  FIGS.  2 A-C  and  3 , the channel  126  also includes a substantially flat surface  156  extending between the end portions  144 ,  148  and the side walls  152 ,  154 . Although the surface  156  may be slightly angled or tapered from the proximal end  150  and the distal end  146 , the surface  156  is substantially flat to support the guidewire  200  along the channel  126  in the embodiment shown in  FIG.  2    and  FIG.  3   . The guidewire  200  includes a distal end (not shown) and a proximal end  202 , and may be composed of one or more metals, one or more plastics, composites, or the like. In some embodiments, the guidewire  200  may include a coating (not shown) that facilitates trackability within patient vasculature and reduces friction while advancing the device  100  over the guidewire  200  or while advancing the guidewire  200  through device  100 . Such coatings may include PTFE, polymer coatings, or ceramic coatings through chemical vapor deposition processes such as atomic layer deposition. 
     In traditional circulatory support devices, as a guidewire is passed through the openings a circulatory support device, or the device moves along a guidewire, the guidewire may be damaged by contact between the guidewire and the device housing. For example, if the housing is made of a metal material, and the guidewire is composed of a softer material or contains a coating, the guidewire may be damaged, or the coating on the guidewire may be scraped off, during contact with relatively abrupt housing surfaces. Also, in traditional circulatory support devices, the guidewire may be bent at a relatively large angle or angles as the guidewire transitions from the interior to the exterior of the device housing. 
     In contrast to traditional devices, the likelihood of damage is substantially decreased with the device  100  due to the guidewire  200  passing through the channel  126 . In particular, the above-described features of the channel  126  substantially reduce the chances that a coating on the guidewire  200  will be scraped off or damaged. In addition, the above-described features of the channel  126  minimize the amount that the guidewire  200  is deformed or bent as it transitions from the interior lumen  102   a  of the impeller housing  102  to the exterior surface  104   c  of the motor housing  104 , providing the guidewire  200  with a flatter profile, and thus advantageously taking up less space within the introducer sheath  300 , as shown in  FIG.  4   . Also, the flatter profile of the guidewire  200  facilitates easier movement of the device  100  along the guidewire  200 , including through the introducer sheath  300  and the blood vessel V. 
     The above-described features of the channel  126  facilitate non-marringly receiving and supporting the guidewire  200  as the guidewire  200  passes through the blood outlet aperture  128 . In particular, the channel  126  in the blood outlet aperture  128  provides a relatively smooth surface for the guidewire  200  to pass from the interior lumen  102   a  of the impeller housing  102  to the exterior surface  104   c  of the motor housing  104 , as shown in  FIG.  3   . By incorporating the sloped, beveled, rounded, or otherwise modified first and second end portions  144 ,  148 , the first and second side walls  152 ,  154 , as well as the flared opening  152  and the substantially flat surface  156 , the likelihood that the guidewire  200  will be damaged as the guidewire  200  passes through the blood outlet aperture  128 , or when the device  100  is moved along the guidewire  200 , is diminished as compared to other blood outlet apertures, such as the blood outlet apertures  130 ,  131 ,  132 ,  133 , and  134 , that do not include such features. For example, the channel  126  reduces the likelihood that a coating on the surface of the guidewire  200  is scraped off when the guidewire  200  passes through the blood outlet aperture  128 , or when the device  100  is moved along the guidewire  200 . 
     In addition, the above-described features of the channel  126  minimize the amount that the guidewire  200  deforms or bends as the guidewire  200  passes from the interior lumen  102   a  of the impeller housing  102  to the exterior surface 104   c  of the motor housing  104 , as shown in  FIG.  3   . Stated another way, by lengthening the transition area from the interior lumen  102   a  of the impeller housing  102  to the exterior surface  104   c  of the motor housing  104 , the guidewire  200  assumes a flatter profile as compared to a guidewire transitioning in another blood outlet aperture, such as the blood outlet apertures  130 ,  131 ,  132 ,  133 , and  134  that do not include a feature like the channel  126 . As noted above, a flatter profile of the guidewire allows the guidewire to take up less space within the introducer sheath  300  and also permits easier movement of the device  100  along the guidewire  200 . 
     With continued reference to  FIGS.  2 A-C  and  3 , in some embodiments, the impeller housing  102  has an outer diameter that is larger than the outer diameter of the motor housing  104 . In alternative embodiments, the outer diameter of the impeller housing  102  may be substantially equal to the outer diameter of the motor housing  104 , for example when impeller housing  102  and motor housing  104  are integrally or monolithically constructed. In still other embodiments, the outer diameter of the motor housing  104  may be larger than the outer diameter of the impeller housing  102 . As shown in  FIGS.  2 A-C  and  3 , a tapered housing portion  160  extends between the impeller housing  102  and the motor housing  104 . The tapered housing portion  160  creates a smooth transition along the housing  101  from the larger outer diameter of the impeller housing  102  to the relatively smaller outer diameter of the motor housing  104 . As shown in  FIG.  2 A-C  and  FIG.  3   , the channel  126  is located in the tapered housing portion  160  and is configured to facilitate the passage of the guidewire  200  from the interior lumen  102   a  of the impeller housing  102  to the exterior surface  104   c  of the motor housing  104 . More specifically, in the embodiment shown in FIG. 2 A-C and  FIG.  3    the channel  126  is designed to minimize the amount that the guidewire  200  deforms or bends as the guidewire  200  passes from the interior lumen  102   a  of the impeller housing  102  to the exterior surface  104   c  of the motor housing  104 . Stated differently, and illustrated in  FIGS.  3  and  4   , when the channel  126  is incorporated into a device  100  with a tapered housing portion  160 , the guidewire  200  extends along the exterior surface  104   c  of the motor housing  104 , passes through the blood outlet aperture  128  and into the interior lumen  102   a  of the impeller housing  102 , while maintaining the same or similar distance from the center axis  103  of the housing  101 . 
     In other embodiments, other portions besides the proximal portion  136  of the blood outlet  128  aperture may include a channel or similar structure for non-marringly receiving and supporting a guidewire. For example, the distal portion  138  of the blood outlet aperture  128  may include a channel or similar structure for non-marringly receiving and supporting a guidewire. In such an embodiment, the interior surface  102   b  of the impeller housing  102  at the distal portion  138  may be configured receive a guidewire, such as by the inclusion of a feature similar to the channel  126  described above. In other embodiments, the interior surface  102   b  of the impeller housing  102  at the distal portion  138  may be modified, sculpted, rounded, or otherwise configured to non-marringly receive and support a guidewire. In addition, in other embodiments, portions of the entirety of a blood outlet aperture may be treated with a coating or surface treatment to prevent damage to a guidewire. In still other embodiments, other apertures, such one or more of the apertures of the blood inlet  114 , may include a channel, such as the channel  126 , or similar structure for non-marringly receiving and supporting a guidewire. 
       FIGS.  2 A-C ,  3 , and  4  facilitate explanation of the method by which the blood pump  100  is used with the guidewire  200  and the advantages provided by the above-described features of the housing  101 , including the channel  126 . In an exemplary procedure, an introducer sheath  300  is inserted into the blood vessel (not shown), and the guidewire  200  is inserted through the introducer sheath  300  such that the proximal end  202  of the guidewire  200  is located outside the introducer sheath  300  and outside of the patient&#39;s body. The distal end (not shown) of the guidewire  200  is disposed distally from the introducer sheath  300  and located within the patient&#39;s vasculature, for example in the left ventricle of the heart. The blood pump  100  is then coupled to the guidewire  200  by feeding the proximal end  202  of the guidewire  200  through an opening in blood pump  100 , such as the blood inlet  114 . The proximal end  202  of the guidewire  200  is then passed through the housing  101 , for example through the interior lumen  102   a  of the impeller housing  102 , past the impeller  112 , and exits the blood pump  100  via another opening, such as the blood outlet  116 , and in particular and as shown in  FIGS.  3  and  4   , through the blood outlet aperture  128 . As the guidewire  200  passes through the blood outlet aperture  128 , the guidewire  200  is received and supported by the channel  126 , thereby inhibiting damage to the guidewire  200  as it contacts the housing  101 .  FIG.  4    in particular illustrates the guidewire  200  extending proximally from the blood outlet aperture  128 , including along the exterior surface  104   c  of the motor housing  104  and within the introducer sheath  300  and blood vessel V. Once coupled to the guidewire  200 , the blood pump  100  is able to be moved along the length of the guidewire  200 , through the introducer sheath  300  to insert the device  100  into the blood vessel V and ultimately into the patient&#39;s heart. 
     Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.