Perfusion of Intrapulmonary Arteriovenous Anastomoses Is Not Related to VO in Hypoxia and Is Unchanged by Oral Sildenafil.

Perfusion of intrapulmonary arteriovenous anastomoses (IPAVA) is increased during exercise and in hypoxia and is associated with variations in oxygen saturation (SO), resulting in blood bypassing the pulmonary microcirculation. Sildenafil is a pulmonary vasodilator that improves SO and endurance performance in hypoxia. The purpose of this study was to determine if 50 mg sildenafil would reduce IPAVA perfusion (Q) and if the decrement in maximal exercise capacity (VO) in hypoxia is related to Q.