Acute pulmonary vasodilator testing is important for patients with pulmonary arterial hypertension, but little is known about the predictors of response to such testing.Methods
Forty-eight patients (mean age, 41.3 ± 11.6 years; 91.7% women) with pulmonary arterial hypertension associated with connective tissue diseases who underwent right-heart catheterization and acute pulmonary vasodilator testing were prospectively recruited. Echocardiography was performed before and immediately after testing.Results
There were 14 responders (29.2%) to acute pulmonary vasodilator testing. Responders had lower pulmonary vascular resistance, higher peak systolic velocity of the lateral tricuspid valve annulus (right ventricular [RV] S′) and tricuspid annular plane systolic excursion, and smaller RV end-diastolic area. After vasodilator testing, mean pulmonary artery pressure and pulmonary vascular resistance decreased significantly in both groups, cardiac index increased significantly in responders, and RV function improved significantly in nonresponders. Receiver operating characteristic curve analysis identified an optimal cutoff value for RV S′ of ≥10.5 cm/sec to predict response, with sensitivity of 71% and specificity of 71%. There were more responders among patients with RV S′ ≥ 10.5 cm/sec (45.5% vs 15.4%, P = .02). On multivariate logistic regression analysis, RV S′ ≥ 10.5cm/sec emerged as an independent predictor of response (odds ratio, 4.58; 95% confidence interval, 1.18–17.79; P = .02).Conclusions
Right-heart function is better in responders to acute pulmonary vasodilator testing than in nonresponders among patients with pulmonary arterial hypertension associated with connective tissue diseases, and pulmonary vasodilators may improve RV function in nonresponders and cardiac index in responders. RV S′ is a simple and clinically useful tool for predicting the results of pulmonary vasodilator testing.