| 摘要 |
<p>A pump including an essentially rigid body open at both ends and insertable into the descending aortic artery; a flexible and resilient sleeve-like membrane (18) sealingly connected to the body around the ends thereof to define, between the body and the sleeve, a variable-volume sealed intermediate space (20) and, inside said sleeve, a variable volume (22) through which the blood to be pumped flows; and means for connecting the intermediate space to a hydraulic fluid source for switching the membrane from a free state to a tensioned state in which it is radially inwardly biased, whereby the volume through which the blood passes is correlatively reduced, and vice versa. The membrane is freely movable relative to the body between the ends thereof, and comprises at least three longitudinal stiffening members (36) evenly spaced around the circumference of the membrane. The stiffening members are intended to cause a local reduction in the longitudinal resiliency of the membrane while imparting a star-like cross-sectional shape thereto when said membrane is in the tensioned state. Said star shape develops gradually between each end region and the intermediate region and leaves a residual region in which there is no contact between different parts of the membrane.</p> |
