Analysis of Pressure Head-Flow Loops of Pulsatile Rotodynamic Blood Pumps

• Published in: Artificial organs Vol. 38; no. 4; pp. 316 - 326
• Main Authors: Jahren, Silje E., Ochsner, Gregor, Shu, Fangjun, Amacher, Raffael, Antaki, James F., Vandenberghe, Stijn
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01.04.2014; Wiley Subscription Services, Inc
• Subjects: Blood; Continuous flow; Heart-Assist Devices; Hemodynamics; Humans; Hybrid mock circulation; In vitro study; Left ventricular assist device; Models, Cardiovascular; Pressure; Pressure head-flow loops; Prosthesis Design; Pulsatile Flow; Pulsatility; Rotodynamic blood pumps; Left ventricular assist device; In vitro study; Hybrid mock circulation; Rotodynamic blood pumps; Pulsatility; Continuous flow; Pressure head-flow loops
• ISSN: 0160-564X; 1525-1594
• DOI: 10.1111/aor.12139

The clinical importance of pulsatility is a recurring topic of debate in mechanical circulatory support. Lack of pulsatility has been identified as a possible factor responsible for adverse events and has also demonstrated a role in myocardial perfusion and cardiac recovery. A commonly used method for restoring pulsatility with rotodynamic blood pumps (RBPs) is to modulate the speed profile, synchronized to the cardiac cycle. This introduces additional parameters that influence the (un)loading of the heart, including the timing (phase shift) between the native cardiac cycle and the pump pulses, and the amplitude of speed modulation. In this study, the impact of these parameters upon the heart‐RBP interaction was examined in terms of the pressure head‐flow (HQ) diagram. The measurements were conducted using a rotodynamic Deltastream DP2 pump in a validated hybrid mock circulation with baroreflex function. The pump was operated with a sinusoidal speed profile, synchronized to the native cardiac cycle. The simulated ventriculo‐aortic cannulation showed that the level of (un)loading and the shape of the HQ loops strongly depend on the phase shift. The HQ loops displayed characteristic shapes depending on the phase shift. Increased contribution of native contraction (increased ventricular stroke work [WS]) resulted in a broadening of the loops. It was found that the previously described linear relationship between WS and the area of the HQ loop for constant pump speeds becomes a family of linear relationships, whose slope depends on the phase shift.