Abstract 11811: Importance of Pulmonary Arterial Capacitance in Pulmonary Hypertension With Left Heart Disease

Abstract

Background: Pulmonary hypertension due to left heart disease (LHD-PH) accounts for the largest proportion of pulmonary hypertension. However, prognostic factor of LHD-PH is poorly understood. Recently, pulmonary arterial capacitance (PAC) has attracted attention for being a factor of right ventricular afterload along with pulmonary vascular resistance. We investigated the clinical significance of PAC in LHD-PH. Methods: Two hundred fifty-two consecutive LHD-PH patients (145 men, mean age 63.4 ± 14.7 year) diagnosed by right heart catheterization were classified into four groups according to the level of PAC. PAC was estimated by the ratio between stroke volume and pulmonary arterial pulse pressure. The end point was a composite of cardiac mortality and rehospitalization due to worsening heart failure. The Cox proportional hazard regression model was used to determine what variables were associated with cardiac events. Results: Fifty-four patients encountered cardiac events during the follow-up period (median 943 days). The event free rate of the 1st quartile was significantly lower than that of the 3rd and 4th quartiles (66.7% vs 82.5% [3rd quartile], P = 0.008; and 92.1% [4th quartile], P < 0.001). The Cox hazard analysis revealed that PAC was associated with cardiac events (HR 0.556, 95% CI 0.424 - 0.730, P < 0.001). Cut-off value of 2.48 ml/mmHg of PAC from ROC curve analysis for prediction of cardiac events had 70.4% sensitivity and 58.1% specificity. Conclusion: PAC is the important prognostic factor in LHD-PH patients. PAC should be taken into account to manage patients with LHD-PH.