Exercise-Induced Pulmonary Arterial Hypertension in Patients With Systemic Sclerosis*

Abstract

Pulmonary arterial hypertension (PAH) is the most common cause of scleroderma-related deaths. New medications for PAH patients make it necessary to identify patients with high risk factors for PAH. This study looks at the use of an exercise echocardiogram in identifying patients who may have PAH and may be candidates for early therapeutic intervention. This study included 54 scleroderma patients with symptoms suggesting they were at risk for pulmonary hypertension, including dyspnea on exertion, diffusing capacity of the lung for carbon monoxide (Dlco)<60% of predicted, FVC<70% of predicted, percentage of predicted FVC/percentage of predicted Dlco (FVC%/Dlco%) ratio>1.6, or resting right ventricular systolic pressure (RVSP)>35 mm Hg. The exercise echocardiogram protocol involved the standard Bruce stress echocardiogram protocol with remeasurement of the RVSP within 1 min of stopping exercise. A positive exercise test result was defined as an increase of at least 20 mm Hg in the RVSP with exercise. Right-heart catheterization with exercise was performed in those with a positive exercise test result. Resting mean RVSP was 34.5 mm Hg, which increased to 51.4 mm Hg with exercise; 44% had at a positive exercise test result, which correlated with a low Dlco, high FVC%/Dlco% ratio (p<0.001), a positive anti-centromere antibody, and RVSP>35 mm Hg (p<0.05). PAH was confirmed by right-heart catheterization in 81% of patients: 19% at rest and 62% of patients with exercise. Exercise-induced pulmonary hypertension is a common finding in patients at high risk for PAH. This may be a sensitive way to identify patients with early PAH. Long-term follow-up and early treatment should be studied in these patients.