Viagra may be of help to heart disease patients

MEDICAL MATTERS

July 07, 2006|By JUDY FOREMAN

Medical Matters Is Viagra, the erectile dysfunction drug, good for the heart, too?

Probably, although more studies are needed.

In the first human study of its kind, Dr. David Kass, a cardiologist at the Johns Hopkins University School of Medicine, reported last fall in the journal Circulation that Viagra can suppress the effects of stress hormones on the heart, a potential boon to many people with heart disease.

In the study, 35 healthy male and female volunteers were given a drug called dobutamine, which stimulates the heart much as the natural hormone, adrenalin, does.

Their hearts responded just as expected - pumping harder and increasing cardiac output. The point of this was to show that their hearts responded to this chemical stress.

About 30 minutes later, Kass divided the group in two. Half got Viagra, the other half, placebo. Neither the doctors nor the subjects knew who got which drug.

About half an hour later, all subjects got another dose of dobutamine. The hearts of people who had gotten Viagra showed less increase in contraction than those of people who got placebo, suggesting, said Kass, that Viagra, also known as sildenafil, "acts like a brake on the heart."

In the penis, Viagra works through a chain of chemical reactions to dilate blood vessels - the key to getting and maintaining an erection. In the heart, Viagra works through the same chemical pathway but the result, instead of vasodilation, is a decrease in the heart's response to stress.

In another study, Kass's team has found this decrease in susceptibility to stress can reduce the thickening of the heart muscle that often follows long-term high blood pressure, a problem called cardiac hypertrophy.

Dr. Michael Mendelsohn, director of the Molecular Cardiology Research Institute at Tufts-New England Medical Center, said that the new evidence of Viagra's effect on the heart means that "it is time to start studying the possibility of using Viagra as a heart drug."

Viagra and similar drugs such as Cialis and Levitra, said Kass, could be taken once a day by people who have thickened heart walls, a problem for about 2.5 million Americans with congestive heart failure.

A new study using Cialis, which is longer acting than Viagra, is expected to begin this month. So far, though, doctors don't recommend taking Viagra for heart problems.

Is lowering salt consumption important for health?

Many medical organizations say yes, though there's room for disagreement.

Last month, the American Medical Association urged the government to develop regulations to limit salt - or sodium - in processed and restaurant foods, noting that excess sodium can increase blood pressure.

A 2004 report by the Institute of Medicine, a branch of the National Academy of Sciences, said that healthy adults should keep their salt consumption under 2,300 milligrams a day. Most Americans consume far more than that, in part because the food industry laces so many products with salt.

Lowering salt consumption can reduce blood pressure, said Dr. Lawrence Appel, a professor of medicine at Hopkins. "Elevated blood pressure is a powerful risk factor for cardiovascular disease and is extremely modifiable by lifestyle changes including sodium reduction," he said. "Reducing salt is even easier for most people than losing weight or making other dietary changes."

While the American Heart Association and the federal government recommend sodium reduction, a review of the issue by the Cochrane Collaboration, an international not-for-profit research group, showed that reducing salt intake is linked to reductions in blood pressure by only a few points.

Moreover, lowering blood pressure by salt reduction may not translate to a survival advantage.

A study published in February in the American Journal of Medicine by Hillel Cohen, an associate professor of epidemiology and population health at the Albert Einstein College of Medicine in New York, concluded that people who reduced salt actually had a 37 percent greater risk of death than those who didn't.

Salt reduction studies, he said, present "a very mixed picture."

One of Cohen's co-authors, Dr. Michael H. Alderman, president of the International Society of Hypertension, has been a consultant, albeit unpaid, to the Salt Institute, an industry group based in Alexandria, Va. The Salt Institute did not pay for the study.

Bottom line? Take all advice on salt, including this, with a grain thereof.

Send your questions to foreman@baltsun.com.

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