WEDNESDAY, Aug. 5 (HealthDay News) -- Patients with pulmonary hypertension and heart failure have stiffer arteries and reduced sensitivity to vasodilators compared with patients without hypertension, which can be reversed by sildenafil (Viagra), according to a study in the Aug. 11 issue of the Journal of the American College of Cardiology.

Vojtech Melenovsky, M.D., and colleagues from the Institute of Clinical and Experimental Medicine-IKEM in Prague, Czech Republic, examined 22 patients with heart failure and high pulmonary vascular resistance (H-PVR) and 24 matched patients with low pulmonary vascular resistance. Blood samples were taken to determine transpulmonary B-type natriuretic peptide (BNP) uptake and cyclic guanosine monophosphate (cGMP) release.

The researchers found that patients with H-PVR had normal BNP uptake, reduced cGMP release, lower pulmonary artery compliance, lower systemic arterial compliance, and a lower cardiac index. These could all be reversed after an oral dose of sildenafil, a phosphodiesterase-5A inhibitor.

"The H-PVR patients have stiffening of both pulmonary and systemic arteries, preserved transpulmonary BNP uptake, but diminished cGMP release, which is reversible by the administration of sildenafil," Melenovsky and colleagues conclude. "This study provides in vivo evidence that phosphodiesterase 5A inhibition restores sensitivity of pulmonary vasculature to endogenous cGMP-dependent vasodilators."

One of the authors is an advisory board member for several biotechnology companies.

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