Long-term effectiveness and predictors of success of low-intensity shockwave therapy in phosphodiesterase type 5 inhibitors non-responders

Objective: To evaluate the long-term (18 months) effectiveness, safety, and factors that may predict the success of low-intensity shockwave lithotripsy (Li-SWT) in patients with erectile dysfunction (ED) who fail to respond to oral phosphodiesterase type 5 inhibitors (PDE5i). Patients and Methods: This prospective study included 52 patients with ED of vascular origin who failed to respond to oral PDE5i. The International Index of Erectile Function-Erectile Function domain (IIEF-EF) and Erection Hardness Score (EHS) questionnaires were used to evaluate EF. Patients under went two Li-SWT treatment sessions per week for 3 weeks, followed by a 3-week treatment-free period, and the cycle was repeated until each patient received 12 treatment sessions. Patients were followed-up after Li-SWT at 3, 6, 12, and 18 months. Results: At the 18-month follow-up, 33 patients (63.5%) were able to achieve an erection sufficient for penetration with or without PDE5i (22 were maintained on oral PDE5i). The remaining 19 patients (36.5%) had a poor response to Li-SWT and oral PDE5i. The initial response showed some decline in 50% of the initial responders. Younger men (aged <45 years), short ED duration (<2 years), and moderate ED severity responded better to Li-SWT. There were no adverse side-effects. Conclusion: In the present study, Li-SWT was a safe and effective treatment in 63.5% of men with ED who failed to respond to oral PDE5i. Factors such as age (<45 years), ED duration (<2 years), and ED severity can predict treatment outcome in such patients. Abbreviations: CDU: colour Doppler ultrasonography; ED: erectile dysfunction; EDV: end-diastolic velocity; EF: erectile function; EHS: Erection Hardness Score; FU: follow-up; IIEF-EF: International Index of Erectile Function-EF domain; Li-SWT: low-intensity shockwave lithotripsy; PDE5i: phosphodiesterase type 5 inhibitors; PGE1: prostaglandin E1; PSV: peak systolic velocity; RI: resistive index; VOD: veno-occlusive dysfunction