Drug Eluting Stent Revascularization for Erectile Dysfunction (ED): Does It Work?
Erectile dysfunction (ED), the recurrent inability to achieve and maintain an erection satisfactory for sexual intercourse, is an important and growing health issue. Although ED is not a life threatening medical problem, successful treatment has a substantial impact on a man’s quality of life. It is estimated worldwide over 200 million men suffer from ED; in the United States, 50% of men between the ages of 40 and 70 years old report some degree of ED. Notably, many experts believe ED is both under reported and under treated.
Current ED evaluation therapies consist of identifying and treating reversible causes and, typically the use of phosphodiesterase-5 (PDE5) inhibitors. Unfortunately, despite the large market in PDE5 inhibitors (Viagra™, Cialis™, Levitra™) 50% of men have a suboptimal response to these inhibitors which worsens over time. Once a male fails PDE5 inhibitors, subsequent therapies tend to be invasive (penile implants), cumbersome and uncomfortable (i.e. intercavernovial injections of vaso-relaxants). As such, there is a substantial clinical need to provide an efficacious easy to use and less invasive therapy for ED.
The currently enrolling ZEN trial (Medtronic Zotarolimus-eluting peripheral stent system for erectile dysfunction treatment in males with suboptimal response to PDE5 inhibitors) tests the hypothesis that drug eluting stent revascularization of an obstructed internal pudendal artery (IPA) may be an important endovascular therapy for arterial vasculogenic ED. This endovascular approach has many potential benefits for men who have suboptimal or failed responses to drug therapy and is clearly less invasive than surgical therapies. The results of this innovative trial will be reported at the late breaking trial session of the VIVA 11 conference in October.
The ZEN trial enrolled 30 patients with established ED, refractory to drug therapy and angiographically confirmed obstructive atherosclerosis in the internal pudendal artery. This important first-in-man, proof of concept feasibility and safety trial included important pre-interventional screening and post-intervention assessment of improvement of patient reported erectile function at 3 and 6 months. Angiographic to assessment of stent patency at 6 months was performed and correlation with patient reported erectile function was assessed. Importantly, ZEN marks an important initial step in the evaluation of endovascular therapies for ED.
The etiology of ED is multifactorial with the majority of cases vasculogenic; either related to inadequate arterial inflow during sexual arousal, impaired cavernosal smooth muscle relaxation, or increased permeability of venous sinusoids leading to "venous leak," most common in diabetics. The epidemiologic link between ED, coronary disease (CAD) and peripheral artery disease (PAD) is of special importance for cardiovascular specialists as all three conditions share the common risk factors of diabetes, dyslipidemia, hypertension and tobacco abuse. Indeed, ED has emerged as a potential harbinger of subsequent cardiovascular events. It is estimated that 70% of men with new onset anginal symptoms and/or angiographically documented coronary disease have some degree of vasculogenic ED.
What is the normal angiographic anatomy of the IPA and how do angiographic findings correlate with ED symptoms? How many men with suspected or known coronary or peripheral arterial disease have significant atherosclerotic IPA disease and ED and could be considered potential candidates for IPA drug eluting stent revascularization? These important questions will be addressed in the ongoing IMPASSE (Incidence of Male Pudendal Artery Stenosis in Suboptimal Erection) study. This important follow-up to ZEN will evaluate the angiographic pattern of potential IPA atherosclerosis disease in 350 men undergoing coronary or peripheral angiographic procedures with a diagnosis or treatment of CAD or PAD at 15 US sites. This registry will attempt to correlate angiographic evidence of IPA atherosclerosis disease in men with and without ED. Men with ED at the time of angiography will be followed longitudinally for three years to assess the potential development ED.
The initial questions posed and to be answered by the ZEN and IMPASSE studies will be important additions to our understanding of vasculogenic ED and assist in the future identification of the appropriate target population. Click Here to contact VIVA for more information.