Left ventricular assist system with a simplified cannulation technique.

A simplified cannulation system was developed without thoracotomy for a ventricular assist system (VAS) that will be applicable even in an emergency. This system consists of an air driven and diaphragm type pump, cannulae, and devices for insertion. The inlet cannula was inserted into the left atrium through the femoral vein using a modified brockenbrough transseptal method. This system was installed without thoracotomy in a chronic experiment in two goats and was removed without any trouble after 14 days of pumping. In a 40 day experiment with this system implanted between the left atrium and the aorta, bypass flow was maintained at 2.7 to 3.3 L/min, and plasma free hemoglobin levels were below 7 mg/dl. When this system was implanted between the left atrium and the aorta, and activated in an induced heart failure goat, output through the pump was 3.0 +/- 0.4 L/min, and mean aortic pressure was increased to 91.7 +/- 15.9 mmHg from 55.8 +/- 15.4 mmHg. This system takes a middle position between an IABP and VAS with thoracotomy in capability of circulatory support and convenience.