Laird Harrison

May 20, 2013

SAN DIEGO, California — One third of the stents used in an experimental treatment for erectile dysfunction partially occluded after 1 year, according to a new study.

"You probably need to design a specific stent for the area," investigator Tobias Köhler, MD, from the Southern Illinois University School of Medicine in Springfield, told Medscape Medical News.

Despite the restenosis rate, the patients maintained high scores on the International Index of Erectile Function 6.

"For many of my patients, it's been a fabulous experience," another of the study investigators, Irwin Goldstein, MD, director of the Institute for Sexual Medicine in San Diego, California, told reporters attending a news conference.

Dr. Köhler and Dr. Goldstein presented the team's results here at the American Urological Association 2013 Annual Scientific Meeting.

Their report updates data provided by the ZEN trial, which attracted a lot of attention because of its novel approach.

Current treatments for erectile dysfunction, such as drugs and vacuum pumps, can be inconvenient and lead to adverse effects, Dr. Goldstein explained. "None of these treatments deal with the cause of the erectile dysfunction."

At the same time, millions of patients receive stents that effectively treat atherosclerosis of their coronary arteries.

 
You probably need to design a specific stent for the area.
 

To test the feasibility and safety of stent therapy for erectile dysfunction, and to measure outcomes, the investigators recruited 30 men with atherosclerotic lesions of the internal pudendal artery.

All had tried phosphodiesterase-5 inhibitors for at least 4 weeks and still scored below 21 on the International Index of Erectile Function 6, all had a peak systolic velocity of less than 30 cm/s bilaterally, and all had angiographic stenosis of 1 or both internal pudendal arteries.

The investigators used zotarolimus-eluting cobalt chromium peripheral stents to treat 45 lesions in the 30 men.

At the 1-year mark, restenosis was found in 11 of the 32 original lesions. That's a much higher rate than is typical for coronary artery stents, said Dr. Köhler.

Mean peak systolic velocity on penile Doppler increased from 16.4 cm/s at baseline to 28.8 cm/sec at 3 months, 42 cm/s at 6 months, and 32.4 cm/s at 1 year.

Although the peak systolic velocity declined from 42.0 cm/s at 6 months to 32.0 cm/s at 12 months, that change could be a statistical artifact, the investigators note.

Anything above 30 cm/s is considered a normal erection, they point out, adding that scores had increased by at least 4 points at 1 year in 81% of the study subjects.

Penile and Heart Blood Flow Differ

The treatment appears to be safe and well-tolerated, the investigators conclude. However, they note that additional research is needed to test whether "pudendal artery stenting is a viable adjunctive treatment for men with vasculogenic erectile dysfunction."

Pudendal arteries are different from the coronary arteries for which the stents were designed, said Dr. Köhler. Although blood flow to the heart is continuous, the penis needs a lot of blood flow for erections but much less the rest of the time.

He speculated that bare-metal stents might work better in pudendal arteries, or perhaps stents that elute more medication.

Dr. Goldstein suggested that just placing a stent might not be enough to help these men. Patients with atherosclerosis of the pudendal artery should control their cholesterol, exercise, and eat a healthy diet, just as patients with coronary atherosclerosis should, he said.

"There has to be active involvement in lifestyle changes," he told Medscape Medical News. "If you're going to do this, you have to realize it's a systemic disease."

This technique is "very interesting and worth pursuing," Ira Sharlip, MD, from the University of California at San Francisco, told Medscape Medical News. However, it will probably only be applicable to a small number of men. "You have to have a very specific blood-flow blockage in the pudendal artery with normal blood flow distal to that."

The investigators estimate that perhaps 3% of men with erectile dysfunction might be candidates. About 30 million men in the United States and 300 million worldwide suffer from the disorder.

Medtronic, which funded this trial, cancelled its plans to pursue the research. Dr. Köhler and colleagues are currently looking for funding to launch a larger trial.

This study was funded by Medtronic. Dr. Köhler reports being a consultant to Medtronic, Coloplast, American Medical Systems, and Actient Pharmaceuticals; a lecturer for Allergan and Auxilium Pharmaceuticals; and having done research for Abbott. Dr. Goldstein is a consultant to Medtronic. Dr. Sharlip has disclosed no relevant financial relationships.

American Urological Association (AUA) 2013 Annual Scientific Meeting: Abstract 1525. Presented May 7, 2013.

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