An expandable percutaneous catheter pump for left ventricular support: proof of concept

OBJECTIVES: We sought to evaluate the performance of a newly designed percutaneous catheter with expandable pump. BACKGROUND: The device was designed as a percutaneously insertable temporary support system for patients with acute left ventricular failure. METHODS: The pump catheter (introduction diameter 9-F) is positioned in the left ventricle. The rotor is driven by an external motor through a flexible drive shaft. A model circuit was used to assess pump performance, hemolysis tests, and particle image velocimetry. The feasibility of the catheter placement and pump operation were examined in 12 anesthetized sheep. Cardiogenic shock was induced in seven of the animals. Cardiac output (CO) and mean aortic blood pressure (MAP) were recorded before and during shock, and during catheter pump action. RESULTS: The catheter pump delivered a flow of 4.1 l/min at a differential pressure of 60 mm Hg. The average modified index of hemolysis was 11.6 (optimum, 1.8). Fluoroscopically and echocardiographically guided in vivo placement and deployment of the device were quick and uncomplicated. Under simulation of acute left ventricular failure (CO 43 +/- 22% and MAP 55 +/- 16% of the baseline value), the catheter pump significantly improved CO to 67 +/- 12% and MAP to 74 +/- 18%. Maximum in vivo duration of operation was 6 h (average, 3.1 +/- 1.4 h). These animal studies revealed: 1) no significant hemolysis (average plasma-free hemoglobin 26 +/- 4 mg/l after 3 h); 2) no thrombotic deposits at rotor or pump housing; and 3) no damage to the endocardium or aortic valve. CONCLUSIONS: A percutaneously insertable, expandable catheter pump is technically and clinically feasible. Our first experimental results are encouraging.