Patent ID: 7524277

Claim:
A method of withdrawing blood from a heart of a body, the heart having an apex in proximity to a left ventricle and an aortic valve fluidicly disposed between the left ventricle and an aorta, the aorta providing a distribution of blood to the body, comprising: a. obtaining a cannula assembly having an outer cannula and an inner cannula, the outer cannula having a transition portion from a first introductory inner perimeter of the outer cannula to a second inner perimeter of the outer cannula, the first introductory inner perimeter being sized in proximity to an outer perimeter of the inner cannula and the second inner perimeter being sized larger than the first introductory inner perimeter, the second inner perimeter forming an annulus around a length of the inner cannula to establish a flow path through the annulus fluidicly separate from a flow path through the inner cannula, the transition portion having a port to allow blood flow into the annulus; b. creating an incision in proximity of the apex of the heart; c. inserting the cannula assembly through the incision and into the left ventricle of the heart, at least a portion of the outer cannula comprising the transition portion and at least a portion of the annulus being disposed in the left ventricle and fluidicly coupled to the left ventricle; d. inserting a portion of the inner cannula through the aortic valve of the heart; and e. allowing blood to be withdrawn from the left ventricle into the port and through the annulus to an outlet of the outer cannula to establish a downstream direction in the annulus flow path along the length of the inner cannula disposed inside the outer cannula while restricting blood flow downstream of the transition portion within the heart along the annulus flow path from external to the outer cannula into the annulus, wherein a portion of the outer cannula downstream of the transition portion is disposed within the heart.