The new small Viennese total artificial heart: experimental and first clinical experiences

For bridging to transplantation, a new small total artificial heart (TAH) design has been developed. Function of the two membrane pumps (filling volume left: 87 ml, and right: 75 ml; four mechanical disc valves and screwed connectors) for orthotopic implantation were studied in calf experiments. A calf survival up to 180 days was achieved without problems by pumping with a rate of 117 +/- 2.4 beats/min and a cardiac output of 7.4 +/- 0.7 L/min. For bridging to transplantation, the New Small Viennese TAH was implanted into a small 45-year-old patient (height 160 cm, weight 75 kg) with end-stage coronary heart disease. The patient deteriorated suddenly [mean aortic pressure: 38 mm Hg; cardiac output (CO): 1.8-2.1 L/min; anuria and multiple organ failure] while waiting for a donor heart. Even though his pericardial space was not enlarged, no fitting problems appeared. By using pumping rates of 104.3 +/- 8.7 beats/min, a cardiac output of 5.8 +/- 0.63 L/min was achieved (free hemoglobin was 4.1 +/- 0.48 mg/dl). Even though blood circulation was reestablished, after a TAH duration of 12 days, multiple organ failure persisted, and TAH bridging had to be stopped. In November 1989, a 50-year-old deteriorating transplant candidate with idiopathic cardiomyopathy was bridged for 6 days. Adjusting the heart rate to 86.5 +/- 11.2 beats/min, a CO of 6.84 +/- 0.46 L/min was achieved (free hemoglobin was 5.9 +/- 1.7 mg/dl). Because of chronic liver dysfunction, the patient developed severe icterus while on the TAH, and it took 2 months after heart transplantation to achieve physiological bilirubin concentrations. The patient recovered fully and remains in excellent condition.