Surgery News - August 2007 - (Page 16)

16 THORACIC SURGERY NEWS • A U G U S T 2 0 0 7 Ventricular Status a Key Criterion for Valve Replacement BY MITCHEL L. ZOLER Else vier Global Medical Ne ws WA S H I N G T O N — Having symptoms is not the only reason that a patient with aortic stenosis may need a new aortic valve. Left ventricular hypertrophy, left ventricular dysfunction, and age are other critical factors when deciding whether a valve replacement is needed, Dr. Tomislav Mihaljevic said at the annual meeting of the American Association for Thoracic Surgery. “We hope our findings will lead to changes in the management of patients with asymptomatic aortic stenosis,” said Dr. Mihaljevic, a thoracic surgeon at the Cleveland Clinic Foundation. Currently, the presence of symptoms is the primary criterion for surgical replacement of the aortic valve in patients with severe aortic stenosis. This means that repair is usually not done until the advanced stages of the disease, with the result that patient survival following valve replacement is often not ideal, he said. “Symptoms alone are inadequate for clinical decision making. We need to pay attention to the ventricular effects of valvular heart disease. Ultimately, these patients will not die from aortic stenosis but from the effects of aortic stenosis on the ventricle, causing left ventricular failure. Left ventricular hypertrophy should not be seen as a benign side effect of aortic stenosis that’s reversed once you replace the aortic valve. Left ventricular hypertrophy is a significant risk factor for bad outcomes even after the aortic valve is re- placed,” he said. Hence, in many patients an aortic stenosis should be fixed before it causes symptoms and before it triggers left ventricular hypertrophy and ventricular failure, Dr. Mihaljevic said. “This study is potentially a landmark. It’s likely to change the management of patients with critical aortic stenosis,” commented Dr. Michael J. Mack, a cardiothoracic surgeon at a cardiopulmonary research institute in Dallas. These results “may lead to earlier operative management of patients with aortic stenosis.” The study reviewed 3,049 patients who underwent valve replacement for severe aortic stenosis at the Cleveland Clinic during 1991-2004. All patients received a bovine bioprosthesis valve. The 10-year survival of these patients was assessed against the expected survival of a com- ULTIMATELY, THESE PATIENTS WILL DIE FROM THE EFFECTS OF AORTIC STENOSIS ON THE VENTRICLE, CAUSING LEFT VENTRICLE FAILURE. parison group that was matched by age, gender, and race. The average age of the patients was about 72 years. The analysis was able to identify several risk factors that were linked with worsethan-expected survival. For example, patients who did not have left ventricular hypertrophy at the time of valve replacement had an “excellent” survival rate of about 65% during the 10 years after surgery. These patients had a left ventricular mass index of less than 100 g/m2 in women and less than 135 g/m2 in men. In contrast, patients with severe left ventricular hypertrophy, a mass index of 185 g/m2 or greater, had a 10-year survival rate of only 35%. This finding highlights the need for cardiac surgeons to use echocardiography to measure hypertrophy, Dr. Mihaljevic said. Ten-year survival rates were about 55% for patients without left ventricular dysfunction and about 30% for those with dysfunction before surgery. The size of the prosthetic valve used also significantly influenced survival, but only in younger patients. Patients younger than 65 years who received a prosthetic aortic valve that was more than 1.5 standard deviations smaller than what was required, based on body surface area, had a significantly worse outcome. In such patients, the best strategy is to use the largest prosthesis possible. But in older patients, the size of the prosthesis had much less impact on survival. Surgeons should “not expose elderly patients to the additional risk of an annulus-enlargement procedure” to accept a larger valve because it won’t improve outcomes. Dr. Mihaljevic stressed that the patients in this series were representative of typical aortic-stenosis patients. Coronary artery disease was common, and about 35% also had aortic regurgitation. In addition, about half the patients also underwent coronary artery bypass surgery. ■ http://www.facs.org/clincon2007/index.html http://www.facs.org/clincon2007/index.html

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Contents Drug Developments News From the College Thoracic Surgery Head & Neck Surgery

Surgery News - August 2007

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