Rotary blood pumps at fixed speeds showed unphysiological responses, with significantly lower preload sensitivity (0.105 vs 0.213 L/min/mm Hg) compared to the natural heart (P<0.001).
How do rotary blood pumps at a fixed speed setting respond to changes in preload and afterload compared to the natural human left ventricle?
Rotary blood pumps at fixed speeds exhibit unphysiological responses to preload and afterload changes compared to the natural heart, highlighting the need for preload-sensitive control mechanisms.
Absolute Event Rate: 0.105% vs 0.213%
p-value: p=<0.001
Responses of four rotary blood pumps (Incor, Heartmate II, Heartware, and Duraheart) at a single speed setting to changes in preload and afterload were assessed using the human left ventricle as a benchmark for comparison. Data for the rotary pumps were derived from pressure flow relations reported in the literature while the natural heart was characterized by the Frank-Starling curve adjusted to fit outputs at different afterloads reported in the literature. Preload sensitivity (mean ± SD) for all pumps at all afterloads tested was 0.105 ± 0.092 L/min/mm Hg, while afterload sensitivity was 0.09 ± 0.034 L/min/mm Hg-values that were not significantly different (t-test, P = 0.56). By contrast, preload sensitivity of the natural heart was over twice as high (0.213 ± 0.03 L/min/mm Hg) and afterload sensitivity about one-third (0.03 ± 0.01 L/min/mm Hg) the values recorded for rotary pumps (t-test, P < 0.001). Maximum preload sensitivity and minimum afterload sensitivity allow the right and left ventricles to synchronize outputs without neural or humoral intervention. This theoretical study reinforces the need to provide preload sensitive control mechanisms of sufficient power to enable the pump and left ventricle in combination to adapt to changes in right ventricular output automatically.
Salamonsen et al. (Tue,) conducted a other in Mechanical circulatory support. Rotary blood pumps (Incor, Heartmate II, Heartware, and Duraheart) vs. Natural heart (human left ventricle) was evaluated on Preload sensitivity (L/min/mm Hg) (p=<0.001). Rotary blood pumps at fixed speeds showed unphysiological responses, with significantly lower preload sensitivity (0.105 vs 0.213 L/min/mm Hg) compared to the natural heart (P<0.001).