AUTHOR=Mulligan Lawrence J. , Thrash Julian , Mitrev Ludmil , Folk Douglas , Exarchakis Alyssa , Ewert Daniel , Hill Jeffrey C. 

TITLE=Evaluation of vascular aging on measures of cardiac function and mechanical efficiency: insights from in-silico modeling

JOURNAL=Frontiers in Cardiovascular Medicine

VOLUME=11

YEAR=2024

URL=https://www.frontiersin.org/journals/cardiovascular-medicine/articles/10.3389/fcvm.2024.1351484

DOI=10.3389/fcvm.2024.1351484

ISSN=2297-055X

ABSTRACT=<sec><title>Introduction</title><p>This study evaluated the hypothesis that vascular aging (VA) reduces ventricular contractile function and mechanical efficiency (ME) using the left ventricular pressure-volume (PV) construct.</p></sec><sec><title>Methods</title><p>A previously published <italic>in-silico</italic> computational model (CM) was modified to evaluate the hypothesis in two phases. In phase I, the CM included five settings of aortic compliance (<italic>C<sub>A</sub></italic>) from normal to stiff, studied at a heart rate of 80 bpm, and phase II included the normal to stiff <italic>C<sub>A</sub></italic> settings evaluated at 60, 100, and 140 bpm. The PV construct provided steady-state and transient data through a simulated vena caval occlusion (VCO). The steady-state data included left ventricular volumes (EDV and ESV), stroke work (SW), and VCO provided the PV area (PVA) data in addition to the three measures of contractile state (CS): end-systolic pressure-volume relationship (ESPVR), <italic>dP/dt</italic><sub>max</sub>-EDV and preload recruitable stroke work (PRSW). Finally, ME was calculated with the SW/PVA parameter.</p></sec><sec><title>Results</title><p>In phase I, EDV and ESV increased, as did SW and PVA. The impact on the CS parameters demonstrated a small decrease in ESPVR, no change in <italic>dP/dt</italic><sub>max</sub>-EDV, and a large increase in PRSW. ME decreased from 71.5 to 60.8%, respectively. In phase II, at the normal and stiff <italic>C<sub>A</sub></italic> settings, across the heart rates studied, EDV and ESV decreased, ESPVR and <italic>dP/dt</italic><sub>max</sub>-EDV increased and PRSW decreased. ME decreased from 76.4 to 62.6% at the normal <italic>C<sub>A</sub></italic> and 65.8 to 53.2% at the stiff <italic>C<sub>A</sub></italic>.</p></sec><sec><title>Discussion</title><p>The CM generated new insights regarding how the VA process impacts the contractile state of the myocardium and ME.</p></sec>