The Influence of Different Operating Conditions on the Blood Damage of a Pulsatile Ventricular Assist Device

Abstract

Because of pulsatile blood flow's benefit for myocardial recovery, perfusion of coronary arteries and end organs, pulsatile ventricular assist devices (VADs) are still widely used as paracorporeal mechanical circulatory support devices in clinical applications, especially in pediatric heart failure patients. However, severe blood damage limits the VAD's service period. Besides optimizing the VAD geometry to reduce blood damage, the blood damage may also be decreased by changing the operating conditions. In this article, a pulsatile VAD was used to investigate the influence of operating conditions on its blood damage, including hemolysis, platelet activation, and platelet deposition. Three motion profiles of pusher plate (sine, cosine, and polynomial), three stroke volumes (ejection fractions) (56 ml [70%], 42 ml [52.5%], and 28 ml [35%]), three pulsatile rates (75, 100, and 150 bpm), and two assist modes (copulsation and counterpulsation) were implemented respectively in VAD fluid-structure interaction simulations to calculate blood damage. The blood damage indices indicate that cosine motion profile, higher ejection fraction, higher pulsatile rate, and counterpulsation can decrease platelet deposition whereas increase hemolysis and platelet activation, and vice versa. The results suggest that different operating conditions have different effects on pulsatile VAD's blood damage and may be beneficial to choose suitable operating condition to reduce blood damage in clinical applications.

A Review of Hemolysis Prediction Models for Computational Fluid Dynamics

“…Mechanical hemolysis, which is the mechanical damage of red blood cells (RBCs) induced by excessively high stress, is a grave issue for the development of all blood pumps . It is encountered in numerous biomedical devices when large velocity gradients are found .…”

Haemolysis induced by mechanical circulatory support devices: unsolved problems

“…In pulsatile ventricular assist devices (VADs), haemolysis is generally lower because flow velocities and shear rates are lower. Xu et al 17 were able to demonstrate that haemolysis in these systems also depends on the operating mode of the pump. In vitro the haemolysis level increases with higher impact rate, higher impact volume and operation with counter-pulsation.…”

Comprehensive Management Considerations of Select Noncardiac Organ Systems in the Cardiac Intensive Care Unit

“…82 In models of pulsatile pumps, it has been implied that the operating parameters determine hemolysis more than patient parameters. 86 The evolution of continuous flow devices in pediatric patients has led to pediatric VAD patients being discharged from the hospital; however, chronic surveillance for hemolysis must be continued. In adult patients, hemolysis is recognized to be common and failure to intervene is associated with cerebrovascular events and death.…”