Optimized performance of the Abiomed BVS 5000: adjustment of the pump height based on Doppler control of the flow pattern

The Abiomed BVS 5000 is an automatic volume-driven paracorporeal pulsatile assist device providing left, right or biventricular support. The paracorpo real position allows optical adjustment of filling volumes of the device, w hich determines the output of the system. A procedure to adjust for maximal stable flow has not yet been established. In vitro measurements have been performed to assess the flow and pressure c haracteristics of the Abiomed BVS 5000 by raising the preload in 5 mmHg ste ps before running the system. Doppler probes were placed at the inflow and outflow lines of the pump. After setting the afterload at 80 mmHg the assis t device was started. Two measurements were performed to find optimal flow (based on Doppler control and optical adjustment). (1) By Doppler control a stable flow pattern was found at a preload of 25 mmHg with a mean atrial p ressure of 5 mmHg and a mean flow of 5.3 +/- 0.7 l/min (mean +/- standard d eviation) at the inflow and outflow sites (the console flow was 4.8 +/- 0.4 l/min with a frequency of 61.8 +/- 2.0 l/min). (2) Optical adjustment of t he pump height gave rise to a preload of 35 mmHg where we recorded a maxima l atrial pressure of 107 +/- 5.8 mmHg, a maximal retrograde flow of -4.3 +/ - 1.2 l/min at the inflow and -1.2 +/- 0.4 l/min at the outflow site. The m ean flow at the inflow and outflow sites was 5.1 +/- 0.5 l/min (the console flow was 4.6 +/- 0.3 l/min with a frequency of 59.6 +/- 2.6 Hz). At an ini tial afterload of 60 and 40 mmHg the system showed the same qualitative beh aviour, but the results were less accurate. Optical adjustment of the pump height may result in an atrioventricular valve insufficiency with undetecte d retrograde flow and high atrial pressures. We conclude that a Doppler flo w probe must be placed at the inflow site to guarantee maximal stable flow.