A new method for the evaluation of erectile dysfunction: sildenafil plus Doppler ultrasonography

Of the various methods of hemodynamic studies performed to evaluate erectile dysfunction penile color Doppler ultrasound is currently considered the best. However, intracavernous injection is invasive and has adverse effects, such as prolonged erection. We evaluated whether sildenafil may be used as a substitute for intracavernous agents when assessing impotence on color Doppler ultrasound.

A total of 42 patients with erectile dysfunction underwent color Doppler ultrasound before and after intracavernous injection of 60 mg. papaverine with genital and audiovisual sexual stimulation. Peak flow and end diastolic velocity were measured in the recorded waveforms obtained 0, 1, 5, 10 and 20 minutes after injection. The patients also underwent color Doppler ultrasound after a 50 mg. oral dose of sildenafil with genital and audiovisual sexual stimulation not before 3 days after the papaverine study. The same parameters were measured at 30, 45, 60, 75 and 90 minutes, and compared with the values obtained after papaverine injection.

Mean peak flow velocity significantly increased after oral sildenafil starting at 30 minutes and achieving a maximum value at 60 minutes. There were no significant differences in the 2 methods in mean peak velocity 1, 5, 10 and 20 minutes after papaverine injection, and 30, 45, 60, 75 and 90 minutes after oral sildenafil administration. Penile color Doppler ultrasound with intracavernous papaverine injection is accepted as the gold standard but color Doppler ultrasound with sildenafil has 90% sensitivity and 100% selectivity for demonstrating arterial insufficiency. Due to prolonged erection 5 patients (11.9%) in the papaverine group required pharmacological detumescence by intracavernous injection. No adverse effects of sildenafil were observed.

Sildenafil administration achieved increased peak flow velocity comparable to that after intracavernous papaverine injection. With no prolonged erection sildenafil emerges as a safer alternative compared to more invasive intracavernous injection.