[Extracorporeal circulatory assistance with centrifugal pumps in postcardiotomy low-output syndrome]. / Extrakorporale Kreislaufassistenz mit Zentrifugalpumpen beim Postkardiotomie-low-output-Syndrom.

From 6/86 to 5/89 seven out of 1700 (0.4%) open heart patients had to be assisted with centrifugal pumps for postcardiotomy low cardiac output syndrome. In 4 cases a left ventricular assist device (LVAD) was used, one case each had a right ventricular assist device (RVAD), an extracorporeal membrane oxygenation (ECMO) and a biventricular assist device (BVAD) with ECMO and ultrafiltration. The last 3 patients were assisted non-pulsatile without intraaortic balloon counterpulsation (IABP) and no impairment of vital organ function was observed. Four out of 7 patients could be weaned from the assist device after a mean of 30 hours (0.5-48). Three patients became long-term survivors with 2 assisted non-pulsatile. Transesophageal echocardiography (TEE) was used to determine the timing for wean off and was found to be an important adjunct to the monitoring of filling--and systemic pressure.

In-vitro assessment of centrifugal pumps for ventricular assist.

Currently two major types of centrifugal pumps are commercially available for ventricular assist: the Biomedicus-cone (Group I) and the Centrimed-impeller pump (now Sarns 3M) (Group II). To compare them for blood trauma and hemolysis, an in-vitro experiment was designed with a Stöckert roller pump as a standard control (Group III). The in-vitro circuit was constructed consisting of a pump head, electromagnetic flow probe, polyvinyl chloride tubing and a reservoir, identical for all groups. Human ACD blood was used for priming and was circulated with a flow rate of 2 L/min for 24 h. Blood samples were taken at 0, 1, 3, 6, 12, and 24 h and zero control values were subtracted from the resulting data per time interval. Among the 16 parameters studied, a highly significant difference in favor of Group I was found for glutamate oxalacetate transaminase (GOT) and lactate dehydrogenase (p less than 0.0001) and for the free plasma hemoglobin (p less than 0.0001) after 12 and 24 h, respectively. The hemolytic index (Allen) again was lowest for group I in contrast to Groups II and III (0.012 versus 0.060 and 1.70) after 24 h. All other parameters studied did not render significant differences between the systems tested. The authors conclude that the Biomedicus pump currently is the least traumatic centrifugal pump for ventricular assist.

[Successful post-bypass extracorporeal circulatory assistance with the centrifugal pump]. / Erfolgreiche post-Bypass extracorporale Kreislaufassistenz mit Zentrifugalpumpe.

Patients with reduced left ventricular function do have an increased risk of inability to be weaned off bypass after open heart surgery despite maximal pharmacologic support and intraaortic balloon counter-pulsation. Centrifugal pumps used for extracorporeal circulatory assist can maintain a patient in low cardiac output up to days without anticoagulation. We used a centrifugal pump in 3 patients: as a left ventricular assist device (LVAD) in 2 patients and right ventricular assist device (RVAD) in 1 patient. One LVAD-patient became a long-term survivor after 20 h of assist, another was bridged successfully to an open heart procedure for 2 h after papillary muscle rupture. One RVAD patient died on the operating table due to massive tracheal bleeding probably caused by pulmonary hypertension.