P2592Incremental predictive ability of baseline and sequential pulmonary artery pressure, RV free wall strain and 6MW in predicting outcome of pulmonary arterial hypertension

Abstract

Background: Pulmonary arterial hypertension (PAH) patients are tracked sequentially throughout treatment with 6MW distance (6MWD) and echocardiography. Single time point measures for these markers are related to outcome, but little is known about the predictive ability of the change of variables. We sought the prognostic implications of change in RV function parameters in PAH. Methods: 96 patients with invasively diagnosed PAH were followed over 3 visits. PASP was assessed with TR velocity, and RV function was measured as RV free wall strain (RVFWS) and tricuspid annular plane excursion (TAPSE), right atrial area (RAA) was used as a surrogate of RV filling pressure, pulmonary artery systolic pressure (PASP) was measured with TR velocity and functional capacity measured with 6MWD. Predictors of mortality were assessed in nested Cox models. Between-visit changes of each variable were averaged for each patient. Patients were categorized in into those who displayed an improvement versus decline, nested Cox models were used to identify independent association with outcome. Results: 29 of 96 pts died after a median follow up of 46 months. The mean change in RVFWS was 0.53±2.0%, 6MWD 13±42 m, PASP -3±11 mmHg. The univariable predictors of death were age, sex, RVFWS and RAA (all p<0.01), but not TAPSE or PASP. Improvement of RVFWS (HR 0.80 [0.38-1.70], p=0.55), 6MWD (HR 0.56 [0.25-1.39], p=0.23) and PASP (HR 0.91 [0.43-1.90], p=0.81) were not associated with outcome. In nested models (Figure 1), RVFWS (HR 0.91, p=0.007) and 6MWD (HR 0.99, p<0.001) but not PASP were independent and incremental to age and sex as predictors of mortality. Conclusion: The baseline echocardiographic parameters are more predictive of long term outcome than changes with treatment. Efforts directed towards assessment of PASP in PAH are less strongly associated with outcome than 6MWD and RVFWS. (Figure Presented).