Chugging to silent machines: development of mechanical cardiac support.

Abstract

The concept of a mechanical device to support failing hearts arose after the introduction of the heart lung bypass machine pioneered by Gibbon. The initial devices were the pulsatile paracorporeal and total artificial heart (TAH), driven by noisy chugging pneumatic pumps. Further development moved in three directions, namely short-term paracorporeal devices, left ventricular assist devices (LVADs), and TAH. The paracorporeal pumps moved in the direction of electrically driven continuous-flow pumps as well as catheter-mounted intracardiac pumps for short-term use. The LVAD became the silent durable electric, implantable continuous-flow pumps. The TAH remains a pneumatically driven pulsatile device with limited application, but newer technology is moving toward electrically operated TAH. The most successful pumps are the durable implantable continuous-flow pumps now taken over by the 3rd-generation pumps for the bridge to transplant and long-term use with significantly improved survival and quality of life. But bleeding including gastrointestinal bleeding, strokes, and percutaneous driveline infections exist as troublesome issues. Available data supports less adverse hemocompatibility of HeartMate 3 LVAD. Eliminations of the driveline will significantly improve the freedom from infections. Restoring physiological pulsatility to continuous-flow pumps is in the pipeline. Development of appropriate right VAD, miniaturization, and pediatric devices is awaited. Poor cost-effectiveness from the cost of LVAD needs to be resolved before mechanical cardiac support becomes universally available as a substitute for heart transplantation.