Comparative Effectiveness Of Pulmonary Vascular Resistance, Capacitance, And Resistance-Capacitance Time In The Escape Trial

Introduction: Right ventricular (RV) function portends adverse outcomes in heart failure (HF). Markers of RV load include pulmonary vascular resistance (PVR), pulmonary capacitance (PC), and the Resistance-Capacitance Time (RCT), a product of PVR and PC. The impact of changes in these indices during hemodynamic optimization is unknown. Hypothesis: PVR, PC and RCT after therapy and changes in these indices during therapy would be differentially associated with outcomes in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization (PAC) Effectiveness (ESCAPE) trial. Methods: Using Cox proportional hazards regression and Kaplan Meier survival analysis, we analyzed associations of PVR, PC, and RCT indices with the outcomes of death, transplantation, and left ventricular assist device (DTxLVAD) and a combined rehospitalization outcome (DTxLVADH) during 6 months follow-up. Results: Among 138 patients (age 56.9 ± 13.6 years, 30.4% female), PVR at the end of therapy was associated with increased DTxLVAD (HR 1.28 per 1 W.U. increase; 95% CI 1.11-1.47; P=0.0007), and final PC was associated with a decreased DTxLVAD (HR 0.60 per unit PC increase; 95% CI 0.41-0.87; P=0.0007). The final RCT was not associated with DTxLVAD (HR 0.70; CI 0.48-1.03; P=0.07). Changes in PVR during therapy (median -0.38 W.U.; IQR -1.57 to 0.62 W.U.) were associated with increased rehospitalization (DTxLVADH) during follow-up (HR 1.13; 95% CI 1.02-1.25; P=0.02). In a binary analysis, patients with an increase in PVR > 0.1 W.U. during therapy had a trend for more DTxLVADH events (log-rank P=0.058; Figure). Changes in PVR and PC during therapy were not associated with survival. Conclusions: Final PVR and PAC measurements but not changes in these parameters during therapy were associated with survival, although changes in PVR during therapy were associated with rehospitalization. More studies are needed to understand the utility of RV load parameters in HF therapy.