Evidence of Inotropic Improvement in LVAD Patients with High I-CARS Score

Abstract

<h3>Purpose</h3> A high INTERMACS Cardiac Recovery Score (I-CARS≥7) has greater likelihood of myocardial recovery in bridge-to-recovery patients compared to a low score (<7). This scoring index was limited in predicting echocardiography changes for an unselected left ventricular assist device (LVAD) population. We investigated its use in predicting pressure-volume (PV) loop changes in bridge-to-transplant patients using non-invasively derived PV loops. <h3>Methods</h3> We prospectively recruited 32 HeartWare Assist Device (HVAD) patients (mean 55.9±12.3 years, 81.3% male) and calculated their I-CARS. HVAD controller-derived parameters and oscillometric brachial pressure (SphygmoCor Xcel) were obtained to non-invasively estimate single-cycle ventricular pressure and volume. PV loops (n=77) and contractile indices were derived at pre-defined timepoints post-implant: 1, 3, 6 months (n=26, 29, 22). The trends of contractility indices, dPdtmax (peak contractility in isovolumic phase), dPdtmax/devP (sensitive to inotropic changes) and dPdtmax/LVEDV (independent of preload), were analysed according to high (≥7) vs low (<7) I-CARS. <h3>Results</h3> I-CARS was calculated in all patients (18.5% I-CARS≥7). Patients with low I-CARS were less likely to have <2 years heart failure diagnosis, more likely to have an implanted ICD and a higher pre-implant creatinine level (Table). Other demographic variables were comparable. Using a statistical linear mixed model, high I-CARS patients demonstrated a 0.50±0.15s monthly increase in dPdtmax/devP (p=0.001) and only modest changes in dPdtmax and dPdtmax/LVEDV (p=0.055, p=0.110). dPdtmax, dPdtmax/devP and dPdtmax/LVEDV remained largely unchanged in low I-CARS patients across the 6-month period. <h3>Conclusion</h3> Selective improvement in dPdtmax/devP amongst high I-CARS patients suggests strong associations between determinants of I-CARS and cardiac contractility. Larger scale studies to understand the determinants of I-CARS and its relation to inotropic improvement would inform remodelling.