Clinical and echocardiographic correlations of exercise-induced pulmonary hypertension in systemic sclerosis: a multicenter study

BACKGROUND: Patients with systemic sclerosis (SSc) are at risk for developing pulmonary hypertension, which is associated with a poor prognosis. Exercise Doppler echocardiography enables the identification of exercise-induced increase in pulmonary artery systolic pressure (PASP) and may provide a thorough noninvasive hemodynamic evaluation. AIM: The aim of this study was to evaluate the clinical and echocardiographic determinants of exercise-induced increase in PASP in a large population of patients with SSc. METHODS: We selected 164 patients with SSc (age 58 ± 13 years, 91% female) with normal resting PASP (<40 mm Hg) who underwent a comprehensive 2-dimensional and Doppler echocardiography and graded bicycle semisupine exercise Doppler echocardiography. Pulmonary artery systolic pressure, cardiac output, and pulmonary vascular resistance (PVR) were estimated noninvasively. Cutoff values of PASP ≥50 mm Hg and PVR ≥3.0 Wood Units at peak exercise were considered a significant exercise-induced increase in PASP and PVR, respectively. RESULTS: Sixty-nine (42%) patients showed a significant exercise-induced increase in PASP. Among them, peak PVR ≥3 Wood Units was present only in 11% of patients, about 5% of the total population. Univariate analysis showed that age, presence of interstitial lung disease, and both right and left diastolic dysfunction are predictors of peak PASP ≥50 mm Hg, but none of these parameters predict elevated peak PVR. CONCLUSIONS: Exercise-induced increase in PASP occurs in almost one-half of patients with SSc with normal resting PASP. Peak exercise PASP is affected by age, interstitial lung disease, and right and left ventricular diastolic dysfunction and, only in 5% of the patients, is associated with an increase in PVR during exercise, suggesting heterogeneity of the mechanisms underlying exercise-induced pulmonary hypertension in SSc.