Bifurcated outflow cannulae

Abstract

A bifurcated cannula for directing blood into the arterial system. The bifurcated cannula including an ingress channel and first and second egress channels. The first egress channel directs a first portion of the blood entering the bifurcated cannula into the arterial system in a first direction. The second egress channel directs a second portion of the blood entering the bifurcated cannula into the arterial system in a direction that opposes the first direction.

1 . A bifurcated cannula for directing blood into the arterial system having blood flowing in a first direction, the bifurcated cannula comprising:
 an ingress channel for receiving blood flow from a pump;   a first egress channel configured to direct a first portion of the blood from the ingress channel into the arterial system in the first direction; and   a second egress channel configured to direct a second portion of the blood from the ingress channel into the arterial system in a direction that opposes the first direction.   
     
     
         2 . The bifurcated cannula of  claim 1 , wherein a cross-sectional area of each of the first and second egress channels determines the first and second portions of blood flowing through the first and second egress channels. 
     
     
         3 . The bifurcated cannula of  claim 2 , wherein cross-sectional areas of the first and second egress channels are sized such that the first portion of the blood is less than the second portion of the blood. 
     
     
         4 . The bifurcated cannula of  claim 2 , wherein cross-sectional areas of the first and second egress channels are sized such that the first and second portions of the blood are each 50% of the blood flowing through the ingress channel. 
     
     
         5 . The bifurcated cannula of  claim 1 , wherein first and second stent grafts are coupled in fluid communication respectively with the first and second egress channels and further adapted to be connected to the arterial system. 
     
     
         6 . The bifurcated cannula of  claim 5 , wherein an outer surface of each of the first and second egress channels includes barbs for retaining the respective stent grafts. 
     
     
         7 . The bifurcated cannula of  claim 1 , wherein an extension tube is coupled in fluidic communication with the ingress channel and further adapted to be connected to the pump. 
     
     
         8 . The bifurcated cannula of  claim 1 , further comprising a flow selector configured to reduce a cross-sectional area of either of the first or second egress channels. 
     
     
         9 . The bifurcated cannula of  claim 8 , wherein the flow selector is an iris having two or more pivotable blades. 
     
     
         10 . The bifurcated cannula of  claim 1  further comprising:
 a first channel fitting received by the first egress channel, wherein a cross-sectional area of a lumen through the first channel fitting is smaller than a cross-sectional area of the first egress channel. 
 
     
     
         11 . The bifurcated cannula of  claim 10 , further comprising:
 a second channel fitting received by the second egress channel, wherein a cross-sectional area of a lumen through the second channel fitting is smaller than a cross-sectional area of the second egress channel.   
     
     
         12 . A method of removing the bifurcated cannula of  claim 1 , wherein first and second stent grafts couple the first and second egress channels to the arterial system, the method comprising:
 disengaging the pump from the ingress channel;   removing the pump;   removing the bifurcated cannula; and   fluidicly coupling the first and second stent grafts such that the blood flowing in the first direction enters the second stent graft and flows into the first stent graft in the first direction and then flows back into the arterial system in the first direction.   
     
     
         13 . A method of directing blood from a pump to the arterial system having blood flowing in a first direction with a bifurcated cannula comprising an ingress channel and first and second egress channels, the method comprising:
 directing the blood from the pump into the ingress channel of the bifurcated cannula;   directing a first portion of the blood through the first egress channel and into the arterial system such that the first portion enters the arterial system in the first direction; and   directing a second portion of the blood entering the bifurcated cannula from the ingress channel through the second egress channel and into the arterial system such that the second portion of the blood enters the arterial system in a direction that opposes the first direction.   
     
     
         14 . The method according to  claim 13 , wherein directing the first and second portions is determined by relative cross-sectional areas of each of the first and second egress channels. 
     
     
         15 . The method according to  claim 13 , wherein the directing of the first and second portions is determined by a flow selector, wherein the flow selector is configured to reduce a cross-sectional area of either of the first or second egress channels. 
     
     
         16 . The method according to  claim 13 , further comprising:
 coupling the first and second egress channels in fluidic communication respectively to the arterial system by first and second stent grafts.   
     
     
         17 . A method of disengaging a circulatory assist system from the arterial system of a patient having blood flowing in a first direction, wherein the circulatory assist system includes a flexible cannula body coupling the left side of the heart of a patient to a pump and a bifurcated cannula comprising an ingress channel for receiving blood from the pump, a first egress channel configured to direct a first portion of the blood from the ingress channel into a first stent graft coupled to the arterial system such that the blood moves in the first direction, and a second egress channel configured to direct a second portion of the blood from the ingress channel into a second stent graft coupled to the arterial system such that the blood moves in a direction that opposes the first direction, the method comprising:
 disengaging the first and second egress channels from the first and second stent grafts; and   fluidicly coupling the first and second stent grafts such that the blood flowing in the first direction enters the second stent graft and flows into the first stent graft in the first direction and then flows back into the arterial system in the first direction.