Effect of sildenafil on arterial stiffness and wave reflection

While sildenafil (Viagra) is widely prescribed for erectile dysfunction, its effect on arterial function is not established. The elastic properties of the aorta, as well as the magnitude and timing of wave reflection, are important factors for efficient performance of the cardiovascular system and have been identified as prognosticators of cardiovascular risk. A total of 24 subjects with coronary artery disease, of whom 14 were hypertensives, aged 69 +/- 8 years, were studied in a randomized, placebo-controlled, double-blind, cross-over design. Measurements lasted for 3 h after the sildenafil intake (50 mg, p.o.) or placebo. Aortic elastic properties were evaluated with carotid-femoral pulse wave velocity; wave reflection was evaluated with augmentation index and augmented pressure of the aortic pressure waveform. Pulse wave velocity decreased significantly (by 0.65 m/s, p = 0.005), denoting a decrease in aortic stiffness. Augmentation index and augmented pressure decreased significantly (by 4.47% absolute and by 4.01 mmHg; p < 0.001 and p = 0.001, respectively), denoting a decreased effect of wave reflection from the periphery. Aortic pulse pressure decreased significantly (by 6.74 mmHg, p < 0.05). An active effect of the drug on aortic wall appears to contribute to the decrease in pulse wave velocity, although other mechanisms such as a decrease of blood pressure and autonomic reflexes could also have contributed. The effect of sildenafil lasted throughout the study (3 h), being evident 30 min after drug intake. In conclusion, this study shows, for the first time, that sildenafil has a favorable effect on aortic stiffness and wave reflection in patients with coronary artery disease. This finding may have important implications for cardiovascular performance and exercise capacity during intercourse.