Objective: This study aims to provide data on the use of oral sildenafil in patients in New York Heart Association functional class III or IV with severe idiopathic pulmonary arterial hypertension unresponsive to conventional therapy.
Method: In this series, six patients with idiopathic pulmonary arterial hypertension were prospectively treated with 2 to 8 mg of oral sildenafil in four to six doses a day. All patients were submitted to physical examination, electrocardiogram and echocardiogram, chest computed tomography, ventilation and pulmonary perfusion scintigraphy, coagulation studies, and tests for collagen vascular disease, acquired immune deficiency syndrome and schistosomiasis in order to rule out secondary causes of pulmonary arterial hypertension. All patients underwent cardiac catheterization for vasoreactivity tests using nitric oxide, O2 at 100% and oral nifedipine, and a 6 minute walking test was performed in those patients who were considered able to exercise.
Results: All patients achieved a good therapeutic response, with improvement by at least one functional class, and presented an increase in systemic arterial oxygen saturation. Five patients showed a decrease in the pulmonary systolic pressure to systemic systolic pressure ratio and improvement in the six-minute walking test. No major side effects were observed at 4 to 36 months of follow-up. One patient had sudden death after sildenafil had been withdrawn by mistake.
Conclusions: These data suggest that sildenafil may be useful in the management of idiopathic pulmonary arterial hypertension. Patients should be advised against the withdrawal of sildenafil without medical supervision.