US Patent 7846083 Left ventricle assist device (LVAD)

A pump has an elongated shell with a generally elliptical shape, an outer convex surface and an inner concave surface. A peripheral side edge located between the inner and outer surfaces terminates in a bead edge. A flexible airtight membrane has a membrane edge bonded to the outer shell surface adjacent to the bead edge. Preforming the membrane edge looped with a maximum linear span of curvature that is greater than a maximal transverse linear extent of the bead edge, membrane operational wear during inflation and deflation cycles is reduced in the region around the bead edge. A process of forming a blood pump with a membrane preform is also provided.