DALLAS, Nov. 11 -- The first comprehensive guidelines to assist physicians in diagnosing and treating the many diseases that can affect the valves of the heart were presented today at the American Heart Association's 71st Scientific Sessions.
"Guidelines for the Management of Patients with Valvular Heart Disease," developed jointly by the American College of Cardiology (ACC) and the American Heart Association (AHA), is the first publication to cover the entire spectrum of heart-valve disorders in one volume. It addresses common disorders such as mitral valve prolapse and aortic stenosis as well as rare ailments. It also provides advice for evaluating and treating adults, teens, and pregnant women with defective valves, and recommends how to assess people who took potentially valve-damaging appetite suppressants.
Heart-valve disease contributed to more than 34,000 deaths and 82,000 hospitalizations in the United States in 1995, according to the American Heart Association. Severe valve problems often require surgery to repair or replace the damaged valve. Valve defects may be inherited or acquired, and the risk of valve damage increases with age.
"It's common for valves, which are opening and closing with every heartbeat during one's life, to eventually develop problems," says Robert O. Bonow, M.D., director of the division of cardiology at Northwestern University Medical School in Chicago and chairman of the joint ACC/AHA Committee on Management of Patients with Valvular Heart Disease. "As the population ages, we are seeing more and more people developing valve disease," he says.
The purpose of the guidelines is to provide recommendations -- based on a thorough evaluation of existing medical studies -- for an area of heart disease in which physicians have often disagreed about when and how to treat the disorder.
"Valvular heart disease is not a single disease," says Bonow. "There are four valves in the heart and different conditions can affect any or all of them. A valve may be too tight or it may not close properly and leak. These conditions, when severe, increase the work of the heart and ultimately may impair the heart's ability to pump blood."
Because few large clinical trials exist in the field of valvular heart disease, the guidelines' authors frequently had to examine a number of small studies to draw their conclusions on any issue. Heart-valve problems are usually first detected when a physician hears a heart "murmur," an abnormal heart sound. Murmurs may indicate a serious valve defect or even a tiny hole in the heart wall, or they may be harmless. A major section of the guidelines deals with evaluating heart murmurs and distinguishing those that are the most serious.
The guidelines are intended not only for cardiologists but also for primary-care physicians, who often are the first to diagnose the condition and treat the patients. Because heart-valve diseases are common in the young as well as the old, the new guidelines offer extensive advice on treating adolescents and young adults with valve defects.
The guidelines provide recommendations on the use of diagnostic tests including when and how often echocardiograms should be performed; offer details on how to care for individuals with a valve defect in whom coronary heart disease develops; and give information about therapy used to prevent blood clots from forming in individuals with artificial heart valves. Also included is information about which valve disorders may cause dire effects during pregnancy and which will not.
"In many cases, these guidelines address issues that doctors have disagreed about for years. The committee has tried to present the guidelines in a balanced fashion," Bonow says. "In some cases a consensus was not reached." Among many recommendations, the guidelines advise:
- All people who took either fenfluramine or dexfenfluramine, alone or with
phentermine, should be examined. The diet-drug combination of fenfluramine and
phentermine is known as Fen-Phen. Fenfluramine and dexfenfluramine were
withdrawn from the market after the discovery last year that they may cause
heart valve damage. The committee recommends a stethoscope examination for
people without symptoms and a follow-up exam six to eight months later if no
problems are found. Those with symptoms or heart murmurs should be examined by
echocardiography (ultrasound of the heart). Individuals in whom a heart murmur
is difficult to detect -- because of body size -- should undergo an ultrasound
exam prior to dental procedures to determine whether they should take
precautions against bacterial endocarditis. Bonow says physicians should use
clinical judgment to determine which patients without symptoms should have
precautionary echocardiograms.
- Some individuals without symptoms who have aortic regurgitation or mitral
regurgitation, in which blood leaks backward through the valve because it does
not close properly, should have surgery to correct the defect. "We have tried
to identify those patients, and we have made recommendations about which ones
should receive vasodilators to try to reduce the amount of regurgitation, or
back flow," Bonow says.
- People with mitral valve prolapse who have mitral regurgitation or severe
thickening of the mitrial valve leaflets should receive antibiotics before
having specific surgical or dental procedures due to the risk of contracting
bacterial endocarditis, an infection of the heart valves caused by bacteria in
the bloodstream. About 5 percent of Americans have mitral valve prolapse, in
which one or both flaps of the valve between the two left chambers of the heart
are enlarged, but most of them have no symptoms and suffer no ill effects.
- By itself, aortic stenosis -- a narrowing of the valve through which blood flows from the heart to the body's main artery -- does not always indicate a need for surgery. "This has been a subject of much debate," Bonow says. "Some physicians would recommend surgery just because a patient has severe aortic stenosis, which may not be necessary. We are recommending surgery for patients who have symptoms or evidence that aortic stenosis is causing the heart muscle to overwork excessively, but not for everybody with this valve problem."
Co-authors of the guideline summary are Blase Carabello, M.D.; Antonio C. de Leon, Jr., M.D.; L. Henry Edmunds Jr., M.D.; Bradley J. Fedderly, M.D.; Michael D. Freed, M.D.; William H. Gaasch, M.D.; Charles R. McKay, M.D.; Rick A. Nishimura, M.D.; Patrick T. O'Gara, M.D.; Robert A. O'Rourke, M.D.; and Shahbudin H. Rahimtoola, M.D.
Members of the ACC/AHA practice guidelines task force are James L. Ritchie, M.D., (chairman); Melvin D. Cheitlin, M.D.; Kim A. Eagle, M.D.; Timothy J. Gardner, M.D.; Arthur Garson, Jr., M.D.; Raymond J. Gibbons, M.D.; Richard O. Russell, M.D.; Thomas J. Ryan, M.D.; and Sidney C. Smith Jr., M.D.
Media advisory: Dr. Bonow can be reached by phone at (312) 908-1105; or by fax at (312) 908-1434. (Please do not publish numbers.)