Cardiac compression band-stay-pad assembly and method of replacing the same

摘要

A ventricular assist device for a heart includes a compression band-stay-pad assembly for encircling substantially the heart perimeter and comprising an elongated band member or chain disposed in a sealed protective structure filled with a lubricating medium. The band member may be fixed at one end and wound upon, or unwound from, a rotatable spool by a drive motor through a speed reducer. Force-transmitting support or stay assemblies are disposed in the protective structure between the band member and a resilient pad assembly for encircling the heart and promoting heart tissue ingrowth therein. The force-transmitting stay assemblies are biased circumferentially, and thus radially outward, by compression return springs disposed therebetween. The resilient pad assembly includes a corrugated surface provided with vertical coil springs, which help prevent damage to heart tissue and facilitate return of the pad assembly to an initial condition, embedded defibrillator electrodes and relatively soft portions to prevent damage to coronary arteries. The device may be constructed so that it can be surgically removed, except for a sealing film and an ingrown pad assembly, which remain in situ on the heart. A net structure suspended below the device supports the apical portion of the heart. In certain embodiments, power or motor devices are provided between respective ones of the force-transmitting stay assemblies to contract and expand the device. The circumferential length of the assembly may be adjustable and/or may comprise two band members movable in opposite directions.