The Efficacy of Penile Duplex Ultrasound in Erectile Dysfunction Management Decision-Making: A Systematic Review

Restorative therapy clinical trials for erectile dysfunction: a scoping review of endpoint measures

Given the lack of regulatory approval for restorative therapies for the treatment of erectile dysfunction, we hypothesized that clinical trials would vary in methodology and endpoint measurements. Our objective was to analyze methodological approaches and outcome measures of clinical trials evaluating restorative therapies for erectile dysfunction. Data was extracted from clinicaltrials.gov on trials which contained the keywords "erectile dysfunction". We evaluated trials initiated between 2004 and 2021 which listed a restorative therapy intervention. We identified 95 trials investigating energy-based/shockwave therapies (60/95), stem cell therapies (25/95), platelet-based therapies (6/95), and others (4/95). Only 41.1% of the trials evaluated safety. The most common efficacy endpoint was International Index of Erectile Function and Sexual Health Inventory for Men, and only 29.5% utilized penile Doppler. Thirty (31.6%) trials had been completed yet only 3 (3.2%) have published results. We found substantial heterogeneity in methodological approach in the trials. Subjective measures of erectile function were commonly reported, but definitions of inclusion criteria and objective outcome measures were inconsistent. These results provide a basis for the design of future clinical trials to improve the quality of trial data and aid in the development of standardized criteria for erectile dysfunction clinical trials.

The penile duplex ultrasound: How and when to perform it?

BACKGROUND

Because it is a superficial structure, the penis is ideally suited to ultrasound imaging. A number of disease processes, including Peyronie's disease, penile fractures and tumors, are clearly visualized with ultrasound. Baseline and dynamic assessment of cavernosal arterial changes after pharmaco-stimulation with alprostadil allows standardized diagnosis of arterial and venogenic causes of erectile dysfunction (ED).

OBJECTIVE

To illustrate how to correctly perform flaccid and dynamic penile duplex ultrasound (D-PDU) and in which patients to recommend it.

MATERIALS/METHODS

An extensive search of the literature was carried out on Pubmed with the insertion of the following Medical Subjects Headings (MeSH) terms and keywords "penile color Doppler ultrasound" "peak systolic velocity" "end-diastolic velocity", "acceleration time", "resistance index".

EVIDENCE

In our experience, arterial erectile dysfunction is identified after standardized intracavernous injection (ICI) of alprostadil (10 mcg) when values of peak systolic velocity (PSV) are <35 cm/s and, in the most severe forms, for values <25 cm/s. Arterial insufficiency can also be identified by increased acceleration time (AT) values (>110 ms) and/or by a lack of visualization of helicine arteries at power Doppler mode along with incomplete achievement of penile rigidity. The veno-occlusive incompetence is determined when end-diastolic velocity (EDV) values are >4.5-5 cm/s or in the case of resistance index (RI) values <0.75. The assessment of additional surrogate markers of endothelial dysfunction, that is, intima-media thickness, mean platelet volume (MPV), endothelial progenitor cells (EPC), endothelial cell specific molecule-1(endocan) are also useful in assessing the patient's cardiovascular risk but are still considered investigational in the interpretation of D-PDU results.

CONCLUSION

D-PDU scan after ICI with vasoactive drugs is a safe procedure and represents the gold standard for the diagnostics of penile pathologies and should be performed in men with ED not responding to oral conventional therapies and/or in those requiring accurate stratification of cardiovascular risk.