Key result
The PII centrifugal pump with a volute casing demonstrated a shallower H-Q curve and greater flow pulsatility synchronized with the native heart beating compared to the PI pump.
Why the study?
Does the design of a centrifugal pump (volute casing and large output port) affect in vivo flow pulsatility in left ventricular assist devices?
Does the design of a centrifugal pump (volute casing and large output port) affect in vivo flow pulsatility in left ventricular assist devices?
Centrifugal pumps for left ventricular assist devices should be designed with a shallow H-Q curve (e.g., using a volute casing and large outlet port) to optimize pulsatility synchronized with native cardiac output.
We have been developing centrifugal pumps for an implantable left ventricular assist device. We manufactured 2 prototype centrifugal pumps (PI, PII). These two have similar designs except for the PII having a volute casing and a large output port. To determine the differences in the hydraulic characteristics between the PI and PII, we carried out in vitro and in vivo experiments. In vitro study showed that the PII had a shallower H-Q curve than that of the PI, and the PII required a pump speed faster than the PI for the same flow rate and pressure head. On the other hand, in vivo study showed that the PII demonstrated a flow pulsatility greater than that of the PI at 1,900 rpm and 8 L/min although no significant change was observed at low pump speeds (< or = 1,500 rpm). This greater pulsatility consisted of a large discharge according to the small differential pressure during the systolic phase and a small discharge according to the large differential pressure during the diastolic phase. In contrast, the PI, having the steeper H-Q curve, showed a small discharge in the systolic phase and a large discharge in the diastolic phase. These results showed that pulsatility synchronized with the native heart beating depended on the slope of the H-Q curve. As a result, the slope of the H-Q curve is important to determine the component of pulsatility synchronized with native cardiac output. Regarding the slope of the H-Q curve, a pump having a volute casing and a large outlet port demonstrates a shallow slope in the H-Q curve. In conclusion, we suggest that a centrifugal pump for use in left ventricular aortic bypass should be designed considering the effect on the native heart pulsatility.
No takes yet. Share an insight, caveat, or question.
Tagusari et al. (1998) studied Left ventricular assist device development. Prototype centrifugal pump PII (with volute casing and large output port) vs. Prototype centrifugal pump PI was evaluated on Flow pulsatility and H-Q curve characteristics. The PII centrifugal pump with a volute casing demonstrated a shallower H-Q curve and greater flow pulsatility synchronized with the native heart beating compared to the PI pump.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: