Echo-Doppler-flowmetric assessment of penile dorsal arteries and their role in the erectile mechanism.

Echo-doppler-flowmetric investigation is the best non-invasive technique for evaluating vascular dynamics of the erection mechanism. Previous studies were carried out with the aim of obtaining some reference parameters for healthy subjects and for subjects affected by impotence with different etiology. All of these studies focused on the penile cavernous artery, neglecting the role played by the penile dorsal artery in the erection process. In this study we examined the flowmetric pattern of the penile dorsal artery before and after intracavernous injection of PGE1 10 micrograms. A significant increase in the velocity of systolic and diastolic velocity was observed in dorsal arteries after intracavernous injection (P < 0.0001) in control subjects and in non-arteriogenic impotent patients. Moreover, the systolic velocity of dorsal arteries presents, after pharmacological stimulation, a statistically significant difference in comparison to the homolateral cavernous artery in non-arteriogenic impotent patients and in healthy subjects. In patients with arterial insufficiency, the absence of the dorsal artery was observed in 5 cases. Furthermore, the systolic velocity of dorsal arteries turns out to be significantly lower than the systolic velocity of dorsal arteries in normal subjects; it is, however, higher than the reference standard for arteriogenic impotent patients. It is likely that the penile dorsal artery, because of its extensive vascular connections with the cavernous artery, provides a hemodynamic support, which can counterbalance slight disorders of cavernous arteries. When the dorsal artery is absent (agenesis, aplasia), or diseased, even slight alterations can result in an early onset of erectile insufficiency.