Right Ventricular Spherical Dilatation Combined with Pulmonary Artery Compliance Predicts Severe-Acute Right Heart Failure after LVAD Implantation

Abstract

Background Right heart failure (RHF) remains a major contributor to morbidity and mortality after left ventricular assist device (LVAD) implantation. Our ability to predict which patients are at highest risk for RHF remains limited. Pulmonary artery compliance (PAC), as a measure of right ventricular (RV) pulsatile load, is associated with RHF after LVAD. We hypothesized that the addition of RV spherical dilatation, which indexes the RV response to load, could further characterize the risk of post LVAD RHF. Methods We retrospectively studied 144 patients who underwent durable LVAD between 2009 and 2018 at our center and had both preoperative echocardiographic and hemodynamic data. RV spherical dilatation (RVs) was indexed by the RV basal short axis length in the apical 4-chamber view. PAC was calculated as SV/(PASP-PADP) and was indexed to body surface area to generate PACi. We generated a new composite variable, the Sphericity Index (SpI), where SpI = RVs/PACi; higher SpI values indicate more composite RV dilatation and pulsatile load. RHF was defined per INTERMACS classifications, with Severe RHF being ≥14d postoperative inotrope dependence and Severe-Acute RHF being need for RVAD or death from RHF. Multivariate logistic regression modeling was used to assess the relationship between SpI and PACi to both Severe and Severe-Acute RHF. Results Forty patients (27.8%) developed Severe RHF and 14 patients (9.7%) developed Severe-Acute RHF. Median PACi and SpI were 0.72 ml/mmHg/m2 (IQR 0.44 ml/mmHg/m2) and 1.62 cm*mmHg/ml/m2 (IQR 1.04 cm*mmHg/ml/m2), respectively. Lower PACi (OR 0.16 [0.04-0.64], p = 0.01) and higher SpI (OR 1.79 [1.12-2.83], p = 0.01) were associated with Severe RHF, adjusted for INTERMACS profile and heart rate. However, only SpI was associated with Severe-Acute RHF (OR 2.69 [1.44-5.00], p = 0.002), whereas PACi did not reach significance (p = 0.06). Conclusion SpI, a composite index combining RV spherical dilatation and PACi, characterizes both RV load and response to load and may predict Severe-Acute RHF after LVAD better than PACi alone.