Prevalence of exercise pulmonary arterial hypertension in scleroderma

Pulmonary arterial hypertension (PAH) is a complication of scleroderma (systemic sclerosis, SSc); as soon as PAH develops, the patient's prognosis deteriorates rapidly. Early detection of PAH ensures timely treatment. We investigated the prevalence of exercise-induced PAH in a cohort of patients with SSc, and examined the relation between exercise-induced PAH and clinical characteristics and biochemical markers.

Patients with SSc and normal resting systolic pulmonary arterial pressure (sPAP) were studied. Eligible patients were asked to perform cycloergometer exercise until exhaustion, and exercise sPAP was measured. All patients had their pulmonary function tested and underwent echocardiography at rest. Brain natriuretic peptide (BNP) was also determined.

Forty-one patients with SSc were studied. Mean sPAP at rest was 29.7 mm Hg, rising to a mean of 41.4 mm Hg on exercise. Eleven of 41 patients (26.8%) had sPAP post-exercise > 50 mm Hg and 8/41 (19.5%) > 55 mm Hg. A significant correlation was found between exercise sPAP and DLCO (p = 0.008) and between sPAP and BNP levels (p = 0.04). Pre-existing severe Raynaud's phenomenon was more prevalent (50% vs 20%), DLCO levels lower (78.9 vs 92.7 % predicted), and BNP levels higher (72.6 vs 42.1 pmol/ml) in patients with exercise sPAP > 55 mm Hg.

The prevalence of exercise-induced PAH in patients with scleroderma is high. Patients with lower DLCO and higher levels of BNP are at higher risk of developing higher sPAP. Studies with longterm followup are required to evaluate the risk of developing resting PAH in these patients.