Production of penile veno-occlusive insufficiency by arterial occlusion in a canine model

Effects of chronic unilateral internal pudendal arterial occlusion on reactivity of isolated corpus cavernosum strips from rabbits

An animal model was developed to elucidate the effect of chronic obstruction of the internal pudendal artery on the responsiveness of the corpus cavernosum. In male albino rabbits, the internal pudendal artery was chronically ligated unilaterally with a silk tie and the occlusion was maintained for 1 month. The control group was sham-operated. The reactivity of corpus cavernosum tissue from the ligated animals and the control animals was studied in organ chambers. Unilateral chronic ligation of the internal pudendal artery caused an impaired contractile response to alpha-adrenoceptor stimulation with decreased Em and pD2 values and an impaired relaxant response to electrical field stimulation but resulted in a marked increase in the endothelium-dependent relaxant response to carbachol with an increased pD2 value. However chronic obstruction of the pudendal artery had no effect on adenosine-, papaverine- and sodium nitroprusside-induced relaxant responses, and there was no change in agonist potency. These data indicate that altered penile hemodynamics have an effect on the reactivity of the corpus cavernosum and may contribute to the etiology of impotence.

Colour duplex sonography in the assessment of impotence

We present our experience with colour duplex sonography (Acuson 128) in the assessment of 83 impotent men. Cavernosal artery measurements were taken before and after the intracorporeal injection of papaverine. The peak velocities following papaverine injection correlated well with the degree of clinical response. Percentage diameter change corresponded with some groups of clinical erection grade, although it was not as good a discriminator as peak velocity. Twelve patients with 24 cavernosal arteries were also examined using pharmacological selective arteriography. Correlation between duplex sonography and arteriography showed an accuracy of 87.5%, specificity of 100.0% and sensitivity of 82.4%. All patients with a clinically good response following papaverine injection had peak bilateral cavernosal artery velocities greater than or equal to 25 cm/s. Amongst the remaining suboptimal responders, 18 also had this finding. Fifteen of these underwent pharmacological cavernosography and 14 exhibited venous leakage. Duplex sonography is a valuable and non-invasive tool in the assessment of impotence and can provide valuable information in deciding the course of further evaluation and treatment. The procedure was always completed more quickly with the guidance of colour Doppler.

High resolution ultrasonography and pulsed wave Doppler for detection of corporovenous incompetence in erectile dysfunction

Cavernosometry and cavernosography have been the primary modalities available for detection and mapping of corporovenous incompetence in patients with erectile dysfunction. These procedures are expensive, time-consuming and associated with some morbidity, prompting us to study a less invasive method, high resolution ultrasonography and pulsed wave Doppler ultrasound. We evaluated 13 patients with nonendocrinological, nonneurological erectile dysfunction by high resolution and Doppler ultrasound for flow in the dorsal and cavernosal veins after intracorporeal papaverine. All patients had a nonrigid response to papaverine and a mean maximum cavernous arterial systolic velocity of greater than 25 cm. per second. The 13 patients were subsequently studied by dynamic cavernosometry and cavernosography, which revealed evidence of venous incompetence (12 with dorsal venous leaks and 11 with cavernous venous leaks). Only 5 of the 12 patients with dorsal venous incompetence had flow detected in the dorsal vein by ultrasound and Doppler studies. High resolution and Doppler ultrasound was unable to detect leakage in the cavernous veins. Among the 2 groups of patients with dorsal venous leaks (those with and without flow detectable by Doppler ultrasound) there was no significant difference in mean cavernous artery diameter or mean cavernous arterial maximum velocity. Similarly, there was no significant difference between the 2 groups in induction, maintenance or initial decompression rates on cavernosometry. We conclude that high resolution and Doppler ultrasound cannot replace dynamic cavernosometry and cavernosography as the diagnostic modality for venous incompetence.

Quantitative and qualitative analysis of dynamic cavernosographies in erectile dysfunction due to venous leakage

Of 521 patients with erectile dysfunction in whom a multidisciplinary approach was used, 145 (27.8%) showed venous leakage as (concomitant) etiology of the impotence in dynamic cavernosography. The rate of the maintenance flow corresponded well with the response to a standardized intracavernosal injection of vasoactive drugs (p less than 0.05) in patients with venous leakage. The maintenance flow increased with the age in secondary impotent men. It was not statistically different in patients with or without concomitant arterial insufficiency (p = 0.19). Fifty-one of 145 patients (32.2%) presented a pathologic cavernosal drainage via a single venous system; 94/145 (64.8%) showed a combined venous leakage. The type of leakage corresponded neither to the maintenance flow nor to the response to intracavernosal injections. Our findings show that standardized intracavernosal testing and Doppler have a high predictive value for the status of the venous occlusive system. Exact evaluation of the type of leakage can be made by bidimensional cavernosography only.

Alpha-adrenoceptor function in isolated penile circumflex veins from potent and impotent men

Alpha-adrenoceptor functions were investigated in isolated human penile circumflex veins from six potent and four impotent men. Contractions elicited by noradrenaline and phenylephrine were inhibited by prazosin, yohimbine, phentolamine and papaverine. No differences were found between vessels from potent and impotent men. The results suggest that alpha-adrenoceptors in penile circumflex veins are of both alpha 1- and alpha 2-type, and that no changes in alpha-adrenoceptor function occur in impotence associated with an increased penile venous outflow.

Duplex scanning in suspected vasculogenic impotence: a worthwhile exercise?

The value of duplex scanning in the assessment of impotence was evaluated in 146 impotent men. Scanning was by means of a Diasonics DRF 400 and penile artery measurements were taken before and after the intracorporeal injection of papaverine hydrochloride. The penile/brachial index was measured in 82 patients and its predictive value compared with the results of duplex scanning and papaverine-induced erection. On scanning evidence of good arterial inflow but poor erections, indirect evidence of venous leakage was assumed. The results showed that the deep artery responses best characterised the erectile response, with the dorsal artery being less helpful. All 37 patients with full erections following papaverine exhibited bilateral deep artery peak velocities of greater than or equal to 25 cm/s. Of the remaining 109 sub-optimal responders, 17 also has this finding; all had undergone dynamic cavernosography, with 16 exhibiting venous leakage. The penile/brachial index was found to classify 13 patients incorrectly. A critical value of deep artery response to attain erection is postulated, enabling more logical use of cavernosography. The penile/brachial index was shown to be suspect and it was concluded that duplex scanning is a useful, non-invasive method in the assessment of impotence.