Extracardiac Mechanical Support Device Placement by a Minimally Invasive Approach is Safe and Effective

Abstract

All current short-term mechanical cardiac assist devices are placed intravascularly and are associated with relatively high rates of thrombosis and infection. We examined a non-blood-contacting extracardiac device that can be inserted with a minimally invasive technique. The CorInnova cardiac assist device consists of 2 polyurethane chambers and a nitinol wire frame. It surrounds the left and right ventricles (fig 1). Its low-profile allows actuation within the pericardium. Air chambers pressurize cyclically to compress the heart during systole. Minimally invasive implantation was assessed in ovine studies. In a beating-heart procedure under general anesthesia, cardiac access was via a 2-3 inch subxiphoid incision. A small pericardial incision was made at the cardiac apex. Under fluoroscopy, the device was advanced to surround the ventricles within the pericardial space (fig 2). After chest closure, fluid was infused into the device's innermost chamber to conform the device to the epicardium. Minimally invasive deployment and attachment was successful for 55 devices in 25 acute studies. No animal sustained any cardiac injury as confirmed by necropsy. The wire frame allowed the device to self-flare around the heart. The intact pericardium kept the device intimately attached to the myocardium. Device-heart coupling was enhanced by the fluid chamber. This feature was verified in several (25+) acute studies and one 5-day study as documented by fluoroscopic imaging and subsequent explant. A novel extracardiac assist device can be placed safely using a minimally invasive procedure.