TY - JOUR
T1 - Hemodynamic exercise responses with a continuous-flow left ventricular assist device
T2 - Comparison of patients’ response and cardiorespiratory simulations
AU - Gross, Christoph
AU - Fresiello, Libera
AU - Schlöglhofer, Thomas
AU - Dimitrov, Kamen
AU - Marko, Christiane
AU - Maw, Martin
AU - Meyns, Bart
AU - Wiedemann, Dominik
AU - Zimpfer, Daniel
AU - Schima, Heinrich
AU - Moscato, Francesco
N1 - Publisher Copyright:
© 2020 Gross et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
PY - 2020
Y1 - 2020
N2 - Background Left ventricular assist devices (LVADs) are an established treatment for end stage heart failure patients. As LVADs do not currently respond to exercise demands, attention is also directed towards improvements in exercise capacity and resulting quality of life. The aim of this study was to explore hemodynamic responses observed during maximal exercise tests to infer underlying patient status and therefore investigate possible diagnostics from LVAD derived data and advance the development of physiologically adaptive LVAD controllers. Methods High resolution continuous LVAD flow waveforms were recorded from 14 LVAD patients and evaluated at rest and during maximum bicycle exercise tests (n = 24). Responses to exercise were analyzed in terms of an increase (") or decrease (#) in minimum (QMIN), mean (QMEAN), maximum flow (QMAX) and flow pulsatility (QP2P). To interpret clinical data, a cardiorespiratory numerical simulator was used that reproduced patients’ hemodynamics at rest and exercise. Different cardiovascular scenarios including chronotropic and inotropic responses, peripheral vasodilation, and aortic valve pathologies were simulated systematically and compared to the patients’ responses. Results Different patients’ responses to exercise were observed. The most common response was a positive change of ΔQMIN" and ΔQP2P" from rest to exercise (70% of exercise tests). Two responses, which were never reported in patients so far, were distinguished by QMIN" and QP2P# (observed in 17%) and by QMIN# and QP2P" (observed in 13%). The simulations indicated that the QP2P# can result from a reduced left ventricular contractility and that the QMIN# can occur with a better left ventricular contractility and/or aortic insufficiency. Conclusion LVAD flow waveforms determine a patients’ hemodynamic “fingerprint” from rest to exercise. Different waveform responses to exercise, including previously unobserved ones, were reported. The simulations indicated the left ventricular contractility as a major determinant for the different responses, thus improving patient stratification to identify how patient groups would benefit from exercise-responsive LVAD control.
AB - Background Left ventricular assist devices (LVADs) are an established treatment for end stage heart failure patients. As LVADs do not currently respond to exercise demands, attention is also directed towards improvements in exercise capacity and resulting quality of life. The aim of this study was to explore hemodynamic responses observed during maximal exercise tests to infer underlying patient status and therefore investigate possible diagnostics from LVAD derived data and advance the development of physiologically adaptive LVAD controllers. Methods High resolution continuous LVAD flow waveforms were recorded from 14 LVAD patients and evaluated at rest and during maximum bicycle exercise tests (n = 24). Responses to exercise were analyzed in terms of an increase (") or decrease (#) in minimum (QMIN), mean (QMEAN), maximum flow (QMAX) and flow pulsatility (QP2P). To interpret clinical data, a cardiorespiratory numerical simulator was used that reproduced patients’ hemodynamics at rest and exercise. Different cardiovascular scenarios including chronotropic and inotropic responses, peripheral vasodilation, and aortic valve pathologies were simulated systematically and compared to the patients’ responses. Results Different patients’ responses to exercise were observed. The most common response was a positive change of ΔQMIN" and ΔQP2P" from rest to exercise (70% of exercise tests). Two responses, which were never reported in patients so far, were distinguished by QMIN" and QP2P# (observed in 17%) and by QMIN# and QP2P" (observed in 13%). The simulations indicated that the QP2P# can result from a reduced left ventricular contractility and that the QMIN# can occur with a better left ventricular contractility and/or aortic insufficiency. Conclusion LVAD flow waveforms determine a patients’ hemodynamic “fingerprint” from rest to exercise. Different waveform responses to exercise, including previously unobserved ones, were reported. The simulations indicated the left ventricular contractility as a major determinant for the different responses, thus improving patient stratification to identify how patient groups would benefit from exercise-responsive LVAD control.
UR - http://www.scopus.com/inward/record.url?scp=85081754511&partnerID=8YFLogxK
U2 - 10.1371/journal.pone.0229688
DO - 10.1371/journal.pone.0229688
M3 - Article
C2 - 32187193
AN - SCOPUS:85081754511
SN - 1932-6203
VL - 15
JO - PLoS ONE
JF - PLoS ONE
IS - 3
M1 - e0229688
ER -
