BACKGROUND: Pulmonary hypertension refers to elevated pulmonary artery pressure. It is a disease of the small pulmonary arteries, characterized by vascular narrowing leading to a progressive increase in pulmonary vascular resistance. It can be primary or secondary to a variety of known causes. Until now, the therapeutic options that are easy to administer, inexpensive and with minimal side effect to control the symptoms and slows down the progression of the disease is limited. Sildenafil, a phosphodiesterase-5 inhibitor (PDE5) that is an approved drug for erectile dysfunction has been reported to improved symptoms and hemodynamic parameters of patients with pulmonary hypertension
OBJECTIVE: The objective of this study is to assess the clinical efficacy of sildenafil among patients with moderate to severe pulmonary hypertension in terms of pulmonary artery pressure, cardiac index (CI), and pulmonary vascular resistance (PVR)
RESEARCH QUESTION: What is the effect of sildenafil in patients with pulmonary hypertension compared with placebo and other drugs indicated for pulmonary hypertension, particularly epoprostenol, a prostacyclin derivative, and a combination of sildenafil and iloprost?
INCLUSION CRITERIA: RCTs on adult patients with pulmonary hypertension, either primary or secondary with pulmonary artery pressure, CI, and/or PVR as among the hemodynamic outcome measures
METHOD: An electronic search thru medline was made. The following key terms were entered: sildenafil and pulmonary hypertension. It was limited to randomized controlled trial, adult 19+, and human. There are only six randomized controlled trials on the medline database. Three RCTs that assessed acute and short-term effects of sildenafil met the inclusion criteria. There is one study found in the free search using yahoo engine search that met the inclusion criteria
RESULTS: For the pulmonary artery systolic pressure (PASP), comparing sildenafil with placebo, correlation coefficient (R) was -0.780 suggesting a large effect. When sildenafil is compared with epoprostenol and a combination of sildenafil and iloprost, the mean pulmonary arterial pressure (mPAP) R is -0.475, showing moderate effect. Comparator groups showed larger effect sizes compared with sildenafil on PVR and CI
CONCLUSION: Sildenafil is a promising drug for pulmonary hypertension, either alone, or as an add-in to current drugs for patients with this condition. Sildenafil showed a large effect size on PASP compared with placebo and moderate lowering effect on mPAP compared with either epoprostenol or sildenafil + iloprost (epoprostenol and iloprost are two of the current standard treatment for pulmonary hypertension). Effect size of sildenafil + iloprost was large compared with sildenafil alone in reducing PVR, while epoprostenol or sildenafil + iloprost showed large effect on CI compared with sildenafil alone. (Author)