Impotence: A Red Flag for Heart Disease
The two share common physiologic pathways, experts say
SUNDAY, Sept. 26, 2004 (HealthDayNews) -- For men, flagging potency can be a red flag that something's not right in the cardiovascular system. And experts say men who rush to fix the problem with impotence drugs may be ignoring a bigger threat to their health.
"Erectile dysfunction [ED] is frequently a manifestation of underlying cardiovascular problems. It even precedes angina -- it can be an early warning, in that respect," said Dr. Andrew McCullough, director of male sexual health, fertility and microsurgery at New York University School of Medicine in New York City.
The advent of Viagra, Cialis and Levitra has put the research spotlight back on ED, and a series of studies are suggesting that, for most men, the condition has physiological, not psychological, origins.
Early in 2004, researchers led by Dr. Alan Bank of the St. Paul Heart Clinic in Minnesota published a study showing that the arteries of men with ED expanded less efficiently than men without erectile difficulties -- a possible sign of underlying heart disease.
McCullough likened ED to a common plumbing problem: "If you turn on your kitchen faucet and you don't get any flow, either the faucet's broken or the pipes are clogged."
For men with advanced heart disease, the clogged-pipe explanation probably holds true, since buildup of cholesterol in arteries can greatly reduce blood flow.
But many men with ED aren't anywhere near this stage of cardiovascular deterioration. For them, the faucet -- the vessels inside the penis and the smooth muscle around them -- may be broken on a biochemical level.
"We're learning that erectile dysfunction is largely due to reduced nitric oxide in the endothelium, the inner lining of blood vessels," explained Dr. David Gutterman, professor of medicine at the Medical College of Wisconsin in Milwaukee.
As blood flow demands increase (as happens during an erection), the endothelium releases nitric oxide to help trigger blood vessel expansion.
"Nitric oxide is very important for normal erectile function," Gutterman said. "It's also -- and here's the link to heart disease -- very important as an anti-atherosclerotic agent, resisting 'hardening of the arteries.' "
In that sense, ED may serve as an early signal that blood vessels elsewhere in the body aren't expanding as they should, either.
It's no coincidence, then, that drugs such as Viagra -- which helps increase nitric oxide levels in the endothelium -- were first studied as possible treatments for cardiac trouble.
"However, it was found that these drugs do this better in some organs rather than others," Gutterman said. "It was found that they work much better for urological problems than for the heart."
Looking at the problem from the other side, Bank's team is currently researching whether or not the statin family of cholesterol-lowering drugs might help fight ED.
"We do know that statins improve the function of the enzyme, nitric oxide synthase, that produces nitric oxide inside the blood vessels," Gutterman pointed out. "That's probably related to the very mechanism that helps get rid of ED."
In the meantime, men with erectile difficulties should stop and consider the possible underlying cause of that dysfunction, McCullough said.
"Initially, when Viagra was first approved, there were all kinds of direct-to-consumer ads associating ED with a physiologic process, to convince men that it wasn't just psychological, and that it might be linked to underlying cardiovascular disease," he said.
"But now, there's a minimalization of all that in these ads. So guys who have these problems just say 'OK, I'll go online and get some Viagra,' " McCullough said.
But that type of attitude has its dangers, he said.
"One of the most serious things, in my mind, is the guy who fails Viagra, Cialis, Levitra. Because to me, that suggests he's got more serious underlying disease than some guy for whom it works," he said.
McCullough's advice? "Go see your doctor."
Gutterman agreed. "Some folks with undiagnosed heart disease might not get chest pain first, but they'll get erectile dysfunction. It's just another way of picking up on early coronary disease."
To learn more about ED, visit the American Academy of Family Physicians.