Novel markers of myocardial recovery in patients with left ventricular assist device: A cardiopulmonary exercise test and hemodynamic analysis

Background: Left ventricular assist device (LVAD)-associated myocardial recovery is possible.Beyond peak O2 consumption (pVO2), parameters obtained from cardiopulmonary exercise testing (CPET), such as post-exercise oxygen uptake recovery delay (VO2RD), ventilatory efficiency (VE/VCO2 slope), and pressure-flow slopes from invasive hemodynamics, may offer novel insights in recovery assessment. Methods:We performed a retrospective analysis of 46 LVAD recipients with CPET (2014-2024), of whom five had complete recovery and LVAD explant (recovered group).A subset (n=23) had invasive hemodynamics during CPET.VO2RD thresholds were defined as the time required for VO2 to fall below 12.5%, 25%, and 50% of pVO2 (T12.5%,T25%, T50%).Pressure-flow slopes were derived by regressing pulmonary artery wedge pressure (PAWP) and mean pulmonary artery pressure (PAP) against cardiac output (CO) throughout exercise.Results: Compared to non-recovered group, recovered patients had higher LVEF (47% [45-48] vs. 19% [16-28], p=0.001), higher pVO2 (14.0 [13.6-20.6] vs. 11.0 [9.9-12.3]ml/kg/min,p=0.007), shorter VO2RD thresholds (T12.5%:31.411.7 vs. 47.719.1sec,p=0.03;T25%: 46.87.1 vs. 65.325sec,p=0.0038;T50%: 8210.1 vs. 99.620.9sec,p=0.027), lower PAWP/CO (1.1 vs.3.6 mmHg/L/min, p=0.003) and PAP/CO (2.4 vs. 4.3 mmHg/L/min, p=0.03) slopes.VE/VCO2 slope components in all exercise phases were similar.Conclusions: VO2RD and pressure-flow slopes were lower in recovered patients, and could be incorporated into a prospective wean protocol assessing for complete myocardial recovery in LVAD-supported patients.