Patent Publication Number: US-2005119599-A1

Title: Supplemental port for catheter perfusion of surgical site and methods of use

Description:
RELATED APPLICATIONS  
      This application is divisional of co-pending U.S. patent application Ser. No. 09/641,012, filed Aug. 16, 2000, which is a continuation-in-part of U.S. application Ser. No. 09/313,268, filed May 18, 1999, now abandoned. 
    
    
     FIELD OF THE INVENTION  
      The present invention relates generally to blood pumps for use during heart surgery. More specifically, the present invention involves providing a supplemental port on a blood pump for delivering blood to a surgical site via a catheter or cannula arrangement to perfuse the tissue downstream from the surgical site.  
     BACKGROUND OF THE INVENTION  
      During open heart surgery and in some emergency cardiopulmonary situations, it is necessary to have some means to bypass the heart with a blood pump. The bypass circuit may be used to completely replace the function of the heart or it may be employed to assist the heart. Typically in a bypass circuit, an inflow cannula is placed within the left ventricle and an outflow cannula is placed within the aorta. Bypass surgery typically is used to repair damaged or occluded vessels on the heart. To repair a vessel or occlusion, the surgeon usually will graft a new vessel that will supply blood to the affected area. Before applying the graft, the surgeon will occlude the target vessel proximally to the damaged area. One problem with doing this is that healthy tissue beyond or downstream from the damaged area no longer receives sufficient blood or oxygen during the operation.  
      Typically, such a circuit will be used for cardiopulmonary arterial bypass graph (CABG) surgery to support or supplement the heart. While CABG surgery may be accomplished on a beating heart or a still heart, the trend is moving towards beating heart surgery because it is less traumatic to the patient. When conducting beating heart CABG surgery, the patient&#39;s vessels and arteries require a replenished flow of oxygenated blood in order for the tissues to sustain without damage. When the surgeon is performing an anastomosis, the target vessel is occluded proximally to the surgical site. Problems associated with occluding the vessel include damage to tissue distal the anastomosis site. In extreme cases, the patient will require a second surgery to correct complications that were created by the first surgery.  
      The present invention is directed at overcoming, or at least reducing the effects of, one or more of the problems set forth above.  
     SUMMARY OF THE INVENTION  
      The present invention concerns a blood pump with a supplemental outflow port(s). A catheter can be attached to the supplemental port at a proximal end, while the distal end of the catheter may be placed where it is desired to have a supplemental blood flow.  
      During CABG surgery, typically one or more of the patient&#39;s vessels are occluded. Once the vessel is occluded, the surgeon may make an anastomosis beyond the occlusion. Typically, the vessel that was occluded does not have any blood flowing through it. One prior art way to remedy this problem is to insert a stent in the area where the anastomosis is going to be placed. Unfortunately, the stent may occupy a large cross-sectional area of the vessel, reducing the overall flow through the vessel such that the area distal to the stent does not receive sufficient oxygenated blood.  
      This supplemental outflow port of the present invention eliminates the need for a stent and provides for a continuous source of oxygenated blood and therefore may reduce the post-surgical damage to the surrounding tissue after an anastomosis has been performed.  
      The present invention also concerns a supplemental inflow port for use with a blood pump. The supplemental input port can be used to input blood from an area other than the main inflow region. For example, blood removed from the heart can be filtered and then introduced back into the patient through the supplemental inflow port.  
      In one broad aspect of the present invention, an apparatus is provided comprising a blood pump, a main inflow port operably connected to the blood pump, a main outflow port operably connected to the blood pump, and a supplemental port operably connected to the blood pump.  
      In one embodiment, the supplemental port is a supplemental outflow port.  
      In one embodiment, the supplemental outflow port is connected to a catheter adapted to supply blood to perfuse a vein or artery.  
      In one embodiment, the supplemental outflow port is connected to a cannula adapted to be positioned in the patient&#39;s aorta.  
      In one embodiment, the supplemental port is a supplemental inflow port.  
      In one embodiment, the supplemental inflow port is connected to a catheter connected to a supply of blood.  
      In one embodiment, the supply of blood is connected to a catheter adapted to be positioned in the body to remove blood from the patient.  
      In one embodiment, the apparatus further comprises a valve at the supplemental port.  
      In one embodiment, the main inflow port is connected to a cannula adapted to be positioned in a patient&#39;s atrium or ventricle.  
      In one embodiment, the main outflow port is connected to a cannula to be positioned in a patient&#39;s aorta.  
      In one embodiment, the main outflow port is connected to a cannula to be positioned within a patient&#39;s artery.  
      In one embodiment, the blood pump is connected to an oxygenator.  
      In another broad aspect of the present invention, an apparatus is provided comprising a blood pump including a main inflow port, a main outflow port, and a supplemental outflow port. The apparatus also includes a perfusion catheter connected to the supplemental outflow port, the catheter adapted to supply blood to an artery on the heart during a bypass operation on that artery.  
      In a still further broad aspect of the present invention, a method is provided comprising the steps of: (a) operably connecting a blood pump to a patient; (b) pumping blood from one part of the heart to another part of the heart; and (c) supplying blood through a supplemental port on the blood pump to an artery one the heart during a bypass operation to that artery.  
      In one embodiment, the blood passes through an oxygenator.  
      In one embodiment, the blood is supplied from the supplemental port to the artery through a catheter.  
      In one embodiment, the blood is supplied from the supplemental port to the artery through a cannula. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a top view of a centrifugal blood pump having a supplemental outflow port in accordance with the present invention;  
       FIG. 2  is a side view of a heart (in partial cross-section) illustrating the use of a pump and cannula system having a perfusion catheter coupled to the supplemental outflow port in accordance with the present invention;  
       FIG. 3  is a side view of a vessel illustrating the positioning of the distal end of the perfusion catheter to deliver blood downstream from the surgical site according to the present invention; and;  
       FIG. 4  is a side view of a centrifugal blood pump and cannula system having a supplemental inflow port for receiving blood from a reservoir. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
      Illustrative embodiments of the invention are described below. In the interest of clarity, not all features of an actual implementation are described in this specification. It will of course be appreciated that in the development of any such actual embodiment, numerous implementation-specific decisions must be made to achieve the developers&#39; specific goals, such as compliance with system-related and business-related constraints, which will vary from one implementation to another. Moreover, it will be appreciated that such a development effort might be complex and time-consuming, but would nevertheless be a routine undertaking for those of ordinary skill in the art having the benefit of this disclosure.  
      The present invention is directed at providing an improved device and related methods for delivering blood and/or other fluids to perfuse tissue and/or organs located downstream from a surgical site. Referring initially to  FIG. 1 , this is accomplished in one basic embodiment by equipping a pump  10  with a supplemental outflow port  12  in addition to the main fluid inflow  14  and main fluid outflow  16  traditionally found in pumps. By way of example only, the pump  10  is presented as a centrifugal blood pump well known in the art. The pump  10  normally operates under the direction of a motor (not shown) which drives an internally disposed impeller (not shown) so as to transport blood from the main fluid inflow port  14  in a generally tangential fashion out the main outflow port  16 . In accordance with one embodiment of the present invention, the supplemental port  12  is formed on the structure defining the main fluid outflow port  16 . As such, blood may be simultaneously directed through both the main outflow port  16  and the supplemental outflow port  12 . As will be explained in greater detail below, when conducting an anastomosis or other surgical procedure that requires a supply of oxygenated blood, a cannula or catheter attached to the supplemental outflow port  12  may be employed to supply a pressurized flow of blood to (or downstream from) a surgical site.  
      Referring to  FIG. 2 , the pump  10  having the supplemental outflow port  12  according to the present invention is illustrated in use as part of a pump and cannula arrangement for providing left-heart assist. More specifically, an inflow cannula  20  is coupled to the main inflow port  14 , an outflow cannula  22  is coupled to the main outflow port  16 , and a perfusion catheter or cannula  24  is coupled to the supplemental outflow port  12 . The inflow cannula  20  is dimensioned to extend through the wall of the left atrium such that its distal end is disposed within the left ventricle. The outflow cannula  22  is dimensioned to extend through the wall of the aorta. Under the direction of the pump  10 , blood may thus be withdrawn from the left ventricle and re-directed into the aorta, effectively bypassing the aortic valve, as may be required for various cardiac surgery procedures. In accordance with one embodiment of the present invention, the perfusion catheter  24  is dimensioned to extend into a blood vessel  30  on the exterior of the heart. More specifically, with combined reference to  FIGS. 2 and 3 , the perfusion catheter  24  is preferably to be positioned within the blood vessel  30  such that the distal end  26  extends past a damaged or diseased section  32  of the blood vessel  30 , which is to be bypassed (such as via a coronary artery bypass graph (CABG) procedure) removed, or otherwise treated. In practice, the target vessel  30  will be occluded upstream of the damaged or diseased section  32 , the occlusion being shown generically at  40 .  
      According to the present invention, positioning the distal end  26  of the perfusion catheter  24  as shown provides the ability to deliver oxygenated blood within the vessel  30  to perfuse the heart tissue located downstream from the occlusion  40 , such as while the surgeon is performing an anastomosis to bypass the damaged or diseased section  32  in CABG procedures. In one embodiment, the distal end  26  of the perfusion catheter  24  may be equipped with a selectively inflatable balloon or similar occluding structure  28  designed to prevent the flow of blood upstream towards the damaged or diseased section  32 . In this fashion, the balloon or occluding structure  28  helps to establish and maintain a bloodless field along a portion of the target blood vessel  30 , thereby easing the challenge for the surgeon in performing the anastomosis.  
      Although shown as part of a left-heart bypass arrangement in  FIG. 2 , it is to be readily understood that the pump  10  having the supplemental port  12  of the present invention may be used in any number of cannulation arrangements for cardiac surgery. These may include (but are not necessarily limited to) pump and cannula arrangements for providing left-heart and/or right-heart support, such as set forth in U.S. patent application Ser. No. 08/891,456, now U.S. Pat. No. 6,123,725 (assigned to the assignee of the present application and filed on Jul. 11, 1997), the entire contents of which are hereby expressly incorporated herein by reference. When employed as part of a right-heart cannulation system, the pump  10  of the present invention would provide venous blood (withdrawn from the right side of the heart) through the supplemental port  12 . Although this venous blood is (by definition) oxygen depleted, this blood supply may nonetheless be helpful in perfusing locations downstream from a surgical site, as even oxygen-depleted blood is better than no downstream blood flow at all. Moreover, while blood pump  10  is shown as a generic centrifugal blood pump, it is to be readily understood that blood pump  10  may comprise any number of blood pumps, including but not limited to the miniature centrifugal blood pump shown and described in U.S. Provisional Patent Application No. 60/178,479 (filed by the assignee of this application on Jan. 26, 2000), the entire disclosure of which is hereby expressly incorporated herein by reference. It should also be appreciated that, although shown and described above in use with the perfusion catheter  24  for tissue perfusion, the supplemental outflow port  12  may have a variety of other uses. These may include (but are not necessarily limited to) use as a pressure tap to determine the pressure of the outflow from the pump  10 , as well as for obtaining blood samples, such as for determining blood. gas content.  
      Referring finally to  FIG. 4 , shown is an alternate embodiment of the present invention. The blood pump  10  is provided with a supplemental inflow port  18  formed as part of the structure defining the main inflow port  14 . Under the direction of the motor (not shown), the internally disposed impeller (not shown) will draw blood through the inflow cannula  20 , through the pump  10 , for delivery out a cannula (not shown) coupled to the main outflow port  16 . In accordance with this aspect of the present invention, the supplemental inflow port  18  will provide the ability to draw another fluid into the pump  10  for delivery out the main outflow port  16 . For example, during most surgical procedures, blood is drained from the patient&#39;s chest cavity through the use of a suction device. Generally, this blood is deposited in a reservoir, such as at  40 , via any suitable tubing or fluid conduit  42 . The reservoir  40  may serve many purposes, such as for removing any bubbles that develop in the blood during suction and/or filtering the blood  44  in order to recondition it for introduction back into the patient&#39;s blood supply. This filtering can be accomplished via any suitable mechanism, such as via the filter shown generally at  46  near the bottom of the reservoir  40 . As blood enters the reservoir  40 , air will migrate towards the surface of the blood  44  and escape into the atmosphere. A return conduit  48  extends between the reservoir  40  and the supplemental inflow port  18  to allow the reconditioned blood  44  to be withdrawn into the blood supply being delivered into the pump  10 . The reservoir  40  may be equipped with a flow regulating mechanism (such as check-valve  50 ) to ensure that the return conduit  48  is occluded in the event the blood  44  within the reservoir  40  drops below a predetermined level.  
      The pump  10 , equipped with the supplemental inflow port  18  according to the present invention, also advantageously allows the physician to infuse any of a variety of fluids into the blood stream of the patient. As well as the infusion of reconditioned or recaptured blood as shown in  FIG. 4 , it may be necessary to infuse fluids or substances such as saline and/or various drugs into the patient. The supplemental inflow port  18  of the present invention also provides the ability to deliver these fluids in large quantities and in quick fashion, which may be required in emergency situations where such actions must be taken to save the life of the patient.  
      As will be appreciated, other combination of the various methods and elements can be used as appropriate. For example, the blood pump of the present invention may be coupled to an oxygenator. While the present invention has been described with reference to the aforementioned examples, this description is not intended to be construed in a limiting sense. It should be readily understood that the components disclosed herein should all be made of materials suitable for medical use, which materials are well known in the art. It should also be understood that all aspects of the present invention are not limited to the specific depictions, and that relative proportions and sizing of the components may vary depending upon the particular situation or application.  
      Various modifications in form and detail of the embodiments shown herein will be apparent to skilled artisans upon reference to this disclosure. It is therefore contemplated that all attendant claims shall cover any such modifications or variations of the described embodiments as following within the true spirit and scope of the present invention.