Delayed erection profiles in men with elevated end-diastolic velocities during penile duplex Doppler ultrasound

Abstract

Background: Penile Doppler ultrasound (PDUS) is considered the gold standard for diagnosing vascular erectile dysfunction. For optimal results, it is essential to fully relax the cavernosal smooth muscle.

Aim: We aimed to profile the end-diastolic velocity (EDV) values and probabilities of delayed erection after PDUS.

Methods: We reported on men who underwent PDUS using a vasoactive agent redosing protocol. The PDUS was performed after the patient achieved full rigidity or the maximum dose of vasoactive agent (up to 100 units) was administered. EDV parameters were assessed. Corporvenocclusive dysfunction (CVOD) was defined as EDV of ≥5 cm/s. Erection rigidity was evaluated 30 minutes after PDUS using the Erection Hardness Scale (EHS). A logistic regression model was created for the outcome of delayed erection (persistent erection or erection achieved after PDUS, EHS ≥ 3) after PDUS with EDV as the predictor.

Outcomes: EDV values and EHS ≥ 3 after completion of PDUS.

Results: 722 men were assessed. Median age was 68 (IQR 62, 73) years. 93% had trimix for the PDUS. Most of the patients (72%) received 100 units of the vasoactive agent. The median EHS during PDUS was 2 (2, 3), median EDV 8.3 (IQR 4, 12) cm/s. Five hundred twenty-three (72%) met the criteria for CVOD during the PDUS. However, 25% of the entire cohort and 12% of those with elevated EDV values required erection reversal. When based on EDV values, the probability of delayed erection was 27% of men with an EDV threshold of 5 cm/s and 11% at 10 cm/s.

Clinical implications: In a redosing PDUS protocol setting, EDV values are insufficient for CVOD diagnosis. Monitoring delayed erection after PDUS is critical. If the patient remains without delayed erection after PDUS, in men who had PDUS with a redosing protocol and it showed high EDV values, CVOD diagnosis is confirmed.

Strengths and limitations: In addition to being an operator-dependent technique, ultrasound can exhibit inter-observer variability. Our rigorous, standardized, and consistent PDUS redosing protocol and the robust statistical analyses are the strengths of this analysis.

Conclusion: In a redosing PDUS protocol, a higher EDV value indicates a lower probability of delayed erection. A quarter of men with EDV values threshold of 5 cm/s, and one-tenth of men with EDV values at 10 cm/s, thus mandating patient monitoring for delayed erection after completion of the study to confirm CVOD diagnosis.

Keywords: accuracy; corporal veno-occlusive dysfunction; erectile dysfunction; penile Doppler ultrasound.