Prevalence and characteristics of moderate to severe pulmonary hypertension in systemic sclerosis with and without interstitial lung disease.

OBJECTIVE: To determine the prevalence and characteristics of moderate to severe pulmonary hypertension (PH) in patients with systemic sclerosis (SSc) with and without interstitial lung disease (ILD).
METHODS: We retrospectively studied clinical and functional characteristics of 197 consecutive patients with SSc who had undergone a screening echocardiography to detect PH.
RESULTS: Moderate to severe PH was suspected in 36 patients (18.3%) and confirmed in 32 who underwent right heart catheterization. The prevalence of PH did not differ between patients with limited and patients with diffuse cutaneous SSc. PH was detected in 12/67 (17.9%) patients without ILD vs 24/110 (21.8%) patients with ILD (p not significant). In patients with ILD, a lower PaO2 appeared as the unique independent factor significantly associated with PH, regardless of the extent of fibrosis. In 3 patients out of 9 (33.3%) with ILD and significantly restrictive disease, PH was out of proportion to the degree of fibrosis. In patients with no ILD, a higher grade of dyspnea appeared as the unique independent factor associated with PH. In patients with no ILD, altered DLCO was the sole indicator of the pulmonary function tests associated with PH (best cutoff value 72%). DLCO correlated with systolic pulmonary arterial pressure only in patients with no ILD.
CONCLUSION: Prevalence of moderate to severe PH was similar in SSc patients with and those without ILD. In patients with ILD, a lower PaO2 was the unique independent indicator associated with PH. In some patients with severe ILD, PH was out of proportion to the degree of fibrosis. A linear correlation between DLCO and systolic pulmonary arterial pressure was observed only in patients without ILD. All these indicators should assist identification of patients with or without ILD requiring diagnostic procedures for PH before annual screening.