Comparative analysis of cardiac mechano-energetics in isolated hearts supported by pulsatile or rotary blood pumps

Benedikt Locher,Nikola Cesarovic,Marcus Granegger,Frithjof Lemme,Martin Schweiger,Emanuel J Hubmann,Young Choi,Michael Hübler,Philipp Aigner

doi:10.1038/s41598-019-56344-8

Abstract

The previously more frequently implanted pulsatile blood pumps (PBPs) showed higher recovery rates than the currently preferred rotary blood pumps (RBPs), with unclear causality. The aim of this study was to comparatively assess the capability of PBPs and RPBs to unload the left ventricle and maintain cardiac energetics as a possible implication for recovery. An RBP and a heartbeat synchronized PBP were alternately connected to isolated porcine hearts. Rotational speed of RBPs was set to different support levels. For PBP support, the start of ejection was phased to different points during the cardiac cycle, prescribed as percentage delays from 0% to 90%. Cardiac efficiency, quantified by the ratio of external work over myocardial oxygen consumption, was determined. For RBP support, higher degrees of RBP support correlated with lower left atrial pressures (LAP) and lower cardiac efficiency (r = 0.91 ± 0.12). In contrast, depending on the phase delay of a PBP, LAP and cardiac efficiency exhibited a sinusoidal relationship with the LAP minimum at 90% and efficiency maximum at 60%. Phasing of a PBP offers the possibility to maintain a high cardiac efficiency and simultaneously unload the ventricle. These results warrant future studies investigating whether optimized cardiac energetics promotes functional recovery with LVAD therapy.

Highlights

The previously more frequently implanted pulsatile blood pumps (PBPs) showed higher recovery rates than the currently preferred rotary blood pumps (RBPs), with unclear causality
Krabatsch et al observed an almost threefold higher chance of cardiac recovery in patients treated with PBPs compared to RBPs5
With the RBP implanted, in six isolated porcine hearts at least three speed settings were recorded with stable cardiac output, aortic pressure (AoP), and heart rate (HR, acceptance criteria ±10%) throughout the speed changes (Table 1)

Summary

Introduction

The previously more frequently implanted pulsatile blood pumps (PBPs) showed higher recovery rates than the currently preferred rotary blood pumps (RBPs), with unclear causality. Phasing of a PBP offers the possibility to maintain a high cardiac efficiency and simultaneously unload the ventricle These results warrant future studies investigating whether optimized cardiac energetics promotes functional recovery with LVAD therapy. Krabatsch et al observed an almost threefold higher chance of cardiac recovery in patients treated with PBPs compared to RBPs5 What causes these differences in cardiac recovery rates between RBPs and PBPs remains unclear. Conditions for reverse remodeling and cardiac recovery with MCS has become an ongoing research topic and major focus in the scientific community[8,9] It is debated whether prolonged MCS support with RBPs may lead to beneficial reverse remodeling but in parallel induce unfavorable myocardial atrophy[15,16]. This decline toward cardiac atrophy could possibly be prevented by providing a balanced degree of ventricular unloading that adequately unloads the LV without inducing the negative cascade toward atrophy

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