Erectile dysfunction may be the first sign of vascular disease in apparently healthy men without clear cardiac risk factors, according to an article in the January 21st issue of the Journal of the American College of Cardiology.

"If a patient does have erectile dysfunction, then we can speculate that he probably has some early disease in other blood vessels in other parts of his body. We don't know if these men are going to go on to develop heart attacks and strokes, but the next step is to look at men like this, and follow them out over time, and see if they are at risk for having other major vascular events," said Alan J. Bank, MD, senior author of the study.

In the current study, American researchers compared 30 men in their mid-40s who had erectile dysfunction but were otherwise apparently healthy with a control group of 27 age-matched men. The participants were recruited through a sexual dysfunction clinic and newspaper advertisements. The study excluded smokers or men who knew they had one or more cardiac risk factors including hypertension, hypercholesterolemia, or diabetes. The researchers also excluded men whose erectile dysfunction appeared to be related to nervous system or psychiatric issues in order to focus on the vascular dysfunction that commonly causes erectile dysfunction.

The two groups were without significant differences in measures such as arterial diameter, intima-media thickness, aortic pulse-wave velocity, and coronary calcification. However, the groups differed significantly in tests of endothelium-dependent and endothelium-independent vasodilation in the brachial artery. When blood flow was constricted and released using a blood pressure cuff and when participants were given nitroglycerin to stimulate vasodilation, the men with erectile dysfunction had significantly reduced responses compared with the control group.

Bank said similar responses to the stimuli of blood pressure cuff and nitroglycerin indicate that the defect in patients with erectile dysfunction appears to be in the vascular smooth muscle.

"Not only is there a defect in the penile smooth muscle, there is also a defect in the smooth muscle in an artery in a different part of the body, the brachial artery in the arm. So we think there is a systemic or generalized defect in the ability of the smooth muscle to relax in response to nitrates," Bank explained.

"It was easy to find men who had erectile dysfunction, but didn't have any other known cardiac disease or blood vessel disease. Then we found that the erectile dysfunction was a very early manifestation of vascular disease; that is, there are many men who have erectile dysfunction as their first symptom of blood vessel disease," Bank added.

In an editorial in the journal, Melvin D. Cheitlin, MD, agreed that physicians should evaluate erectile dysfunction patients for the presence of vascular disease and question vascular disease patients about erectile dysfunction: "The important message here is that many patients with erectile dysfunction have a vascular mechanism similar to that seen in atherosclerosis and that its presence should alert the clinician to the possible presence or future development of vascular disease."

Cheitlin wrote that the study produced intriguing findings that will have to be confirmed. "The question arises as to whether all known risk factors were ruled out: Lipoprotein (a), elevated homocysteine, glucose intolerance, and insulin resistance were not examined. It is possible that the patients had risk factors predisposing them to atherosclerosis. Still, the earliest sign before any demonstrable vascular disease was the development of erectile dysfunction," he concluded.