Severe aortic stenosis without symptoms — A clinical challenge

Tuesday, October 07, 2008

SCOTTSDALE, Ariz. – A routine physical can uncover the condition when the physician discovers a heart murmur. Left undetected, however, the heart muscle weakens, blood flow is constricted and the result can mean sudden death or life-threatening heart failure.

Aortic stenosis, or aortic valve stenosis, can hamper normal life activities, straining the heart and causing shortness of breath, chest pain and fainting. The patient is also at risk for endocarditis, an infection of the heart's inner lining.

Treatment for aortic stenosis, depending on severity of symptoms, has ranged from the conservative – medications – to the much more aggressive – repair or replacement of the aortic valve (aortic valve replacement) – to allow blood to flow normally into the aorta and the rest of the body.

Now a Mayo Clinic study suggests that some patients who remain asymptomatic despite severe aortic stenosis may need close observation and careful calculation of risk, involved in "watchful waiting" to monitor the disease progression before undergoing a timely valve replacement surgery.

According to Bijoy Khandheria, M.D., Chair of Cardiology, Mayo Clinic, co-author of the study, "Patients with severe aortic stenosis can be relatively free of symptoms, yet be at risk for serious consequences, such as sudden cardiac death." This presents a significant challenge for the physician, Dr. Khandheria added. "We have to weigh the individual patient risks for aortic valve replacement versus watchful waiting – risking sudden cardiac death or doing the valve surgery on the patient at a much later, non-optimal age."

Another complicating factor is that the absence of symptoms in a patient may delay detection of aortic stenosis and therefore delay treatment options. "Even more risky is the situation where the patient, previously asymptomatic, suddenly develops symptoms, particularly over a short period of time. The prognosis is often a bleak picture," warns Partho Sengupta, M.D., the corresponding author of the study. Patients are therefore counseled to self-report the onset of any symptoms, advice that although wise, can have its own complications. Patients may subconsciously dial down their daily activities, and as a result, may appear "asymptomatic," an outcome that can delay treatment, according to Dr. Sengupta.

So why not advocate preemptive surgery in the asymptomatic patient to ensure intervention in a timely manner and not risk doing the surgery when the patient may be considered too old?

"That may be the way to go in the future," advises Dr. Khandheria, "But for now, our study indicates that unselected, premature aortic valve replacement surgery carries a number of risks, including valve prosthesis complications, as well as risk of anti-coagulation-related bleeding and infective endocarditis." He also notes that surgical mortality increases progressively with age, and is up to 9 percent in patients over age 80.

Importantly, according to the study findings, surgical intervention as standard for the asymptomatic aortic stenosis patient will depend on the yet unproven myocardial function assessment and improvements in valve design. Such expedited surgery may be reasonable, however, for those patients with higher risks for severe valve calcification and accompanying coronary artery disease.

The watchful waiting approach for patients without symptoms, while largely favored, should incorporate close monitoring and follow-up, the study advises.

One in four patients over age 65 has evidence of aortic sclerosis (calcium accumulation on the aortic valve) and more than 4 percent of the North American population age 75 or older has aortic stenosis.

The study, called "Management of Asymptomatic Severe Aortic Stenosis," was published in the Oct.14 issue of the Journal of the American College of Cardiology.

Other Mayo Clinic investigators of the study were Mackram Eleid, M.D.; Farouk Mookadam, M.D. and Federico Gentile, M.D.

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Mayo Clinic is the first and largest integrated, not-for-profit group practice in the world. As a leading academic medical center in the Southwest, Mayo Clinic focuses on providing specialty and surgical care in more than 65 disciplines at its outpatient facility in north Scottsdale and at Mayo Clinic Hospital. The 244-licensed bed hospital is located at 56th Street and Mayo Boulevard (north of Bell Road) in northeast Phoenix, and provides inpatient care to support the medical and surgical specialties of the clinic, which is located at 134th Street and Shea Boulevard in Scottsdale.

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