An emergency balloon occlusion system for a rotary blood pump left ventricular assist system

A fatal outcome is expected in a left ventricular assist system (LVAS) util izing a rotary blood pump if there is no mechanism to prevent the backflow from the aorta to the heart in the case of acute pump failure. To solve thi s problem, a passive mechanical clamping system at the outflow graft of a r otary blood pump was developed together with Fuji Systems, Inc., Yokohama, Japan. The system consisted of an emergency clamp port and an occlusion bal loon. The balloon was fixed around the outlet graft of the LVAS. In an in v itro study, a fail-safe clamping operation with 2 ml saline injection under 7 L/min flow against 140 mm Hg pressure reduced the flow to 0.5 L/min whil e the pressure in the system increased to 190 mm Hg. The systems were also applied to 2 in vivo LVAD studies. When the pumps were stopped, there were approximately 3.0 L/min regurgitant flows. The balloon occluder prevented t his regurgitant flow effectively against a 100/80 mm Hg arterial pressure. In conclusion, this emergency balloon occlusion system is relatively easy t o operate and will work efficiently in all possible clinically encountered malfunctions of the rotary blood pump LVAS.