What nonresponse to intracavernous injection really indicates: a determination by quantitative analysis

Area of Science:

• Urology
• Andrology
• Sexual Medicine

Background:

• Intracavernous injection (ICI) is used therapeutically and diagnostically for erectile dysfunction (ED).
• A positive response to ICI rules out venous leakage, but a negative response may not accurately reflect erectile function.
• Quantitative analysis is needed to understand the significance of failed responses to ICI testing.

Purpose of the Study:

• To quantitatively analyze the significance of failed responses to intracavernous injection testing in patients with erectile dysfunction.
• To identify predictors of non-response to ICI testing.

Main Methods:

• 122 patients with ED underwent a standard assessment including a test dose of ICI (papaverine, phentolamine, prostaglandin E1).
• All patients subsequently underwent nocturnal penile tumescence testing, penile blood flow study, and re-dose pharmacocavernosography.
• Results were quantitatively compared to the ICI test outcome using Receiver Operator Characteristics (ROC) curve analysis.

Main Results:

• 87 patients failed to respond to the initial ICI test.
• Non-responders were older (46.8 vs 33.8 years) and had longer ED duration (31.0 vs 13.7 months) than responders.
• ED duration (ROC 0.99), patient age (ROC 0.87), maintenance flow (ROC 0.86), pressure loss (ROC 0.83), and resistive index (ROC 0.82) were the best predictors of ICI test response.

Conclusions:

• Age and ED duration are key factors influencing ICI test results.
• In men over 40 with ED >2 years, non-response to ICI is strongly linked to venous insufficiency.
• Venous leakage is the likely cause of failed ICI tests in older men with long-standing ED; cavernosometry offers valuable confirmatory data.