Increased sympathetic tone may cause an equivocal response to a
prostaglandin E1 (
PGE1) penile Doppler ultrasound (US) examination interpreted as a venous leak. We evaluated the US parameters and erectile response to the addition of
phentolamine to a
PGE1 penile Doppler US examination to ascertain whether addition of
phentolamine would abolish a suboptimal response. 32 patients (median age 29 years, range 17-70 years) with either a previous Doppler US pattern of venous leakage or a clinical suspicion of
venogenic impotence, underwent Doppler US after a total dose of 20 microg of
PGE1. Peak systolic velocity (PSV), end diastolic velocity (EDV) and grade of erection were documented. If erectile response was suboptimal irrespective of the EDV measurement, 2 mg-intracavernosal
phentolamine was administered and measurements repeated. Six patients had a normal erectile response, the remaining 26 received
phentolamine. A significant increase in PSV between baseline and 20 microg
PGE1 (p<0.001) was observed in all cases. Following
phentolamine there was a significant increase in grade of erection (p=0.0001) and a significant reduction in the EDV (p=0.0001). A reduction of the EDV to below 0.0 cm s(-1) was observed in 16 patients. Four patients with EDV <5.0 cm s(-1) but >0.0 cm s(-1) had improved erectile response following
phentolamine while six showed persistent EDV elevation >5 cm s(-1). No
priapism was documented. It is essential to ensure cavernosal relaxation using
phentolamine before a Doppler US diagnosis of venous leak is made. This two-stage assessment will allow this to be done efficiently and with a low risk of
priapism.