August 14, 2013

Surgery For Heart Valve Disorder Associated With Greater Long-Term Survival

In a study that included patients with mitral valve regurgitation due to a condition known as flail mitral valve leaflets, performance of early surgical correction compared with initial medical management was associated with greater long-term survival and lower risk of heart failure, according to a study in the August 14 issue of JAMA.

"Degenerative mitral regurgitation [backflow of blood from the left ventricle to the left atrium due to mitral valve insufficiency] is common and can be surgically repaired in the vast majority of patients, improving symptoms and restoring normal life expectancy. Despite the safety and efficacy of contemporary surgical correction, an ongoing international debate persists regarding the need for early intervention in patients without American College of Cardiology (ACC)/American Heart Association (AHA) guideline class I triggers (no or minimal symptoms and absence of left ventricular dysfunction). This is in part propagated by discordant views of the prognostic consequences of uncorrected severe mitral regurgitation; considered as benign by those supporting medical watchful waiting (nonsurgical observation until a distinct event is encountered) vs. conveying excess mortality and morbidity (including heart failure and atrial fibrillation) by those advocating early surgical intervention," according to background information in the article.

To understand the comparative effectiveness of early surgery vs. initial medical management strategies, Rakesh M. Suri, M.D., D.Phil., of the Mayo Clinic College of Medicine, Rochester, Minn., and colleagues conducted a study to ascertain the comparative effectiveness of initial medical management (nonsurgical observation) vs. early mitral valve surgery following the diagnosis of mitral regurgitation due to flail leaflets (an abnormality of the mitral valve in which a portion of the valve has lost its normal support). For the study, the researchers used data from the Mitral Regurgitation International Database (MIDA) registry, which includes 2,097 patients with flail mitral valve regurgitation (1980-2004) receiving routine cardiac care from 6 tertiary centers (France, Italy, Belgium, and the United States). Of 1,021 patients with mitral regurgitation without ACC and AHA guideline class I triggers, 575 patients were initially medically managed and 446 underwent mitral valve surgery within 3 months following detection.

Within 3 months following diagnosis, 8 patients died, 5 (1.1 percent) after early surgery vs. 3 (0.5 percent) during initial medical management; 9 patients developed heart failure, 4 (0.9 percent) after early surgery vs. 5 (0.9 percent) during initial medical management; and 30 patients developed new-onset atrial fibrillation, 6.2 percent after early surgery vs. 1.2 percent during initial medical management.

Ninety-eight percent of patients were followed up from diagnosis until death or at least 5 years. A total of 319 deaths were observed during an average follow-up time of 10.3 years. "Survival among the entire unmatched cohort for early surgery was 95 percent at 5 years, 86 percent at 10 years, 63 percent at 20 years vs. 84 percent at 5 years, 69 percent at 10 years, and 41 percent at 20 years for initial medical management, favoring early surgery," the authors write. Early surgical correction of mitral valve regurgitation was associated with a 5-year reduction in mortality of 53 percent.

With class II triggers (atrial fibrillation or pulmonary hypertension), survival was again better with early surgery, both overall and in the matched cohort at 10 years.

During follow-up, 167 patients incurred at least 1 incident episode of heart failure representing a rate of 16 percent at 10 years and 27 percent at 20 years. In the overall cohort, heart failure was less frequent after early surgery (7 percent for early surgery vs. 23 percent for initial medical management at 10 years and 10 percent for early surgery vs. 35 percent for initial medical management at 20 years), with a heart failure risk reduction of approximately 60 percent.

Reduction in late-onset atrial fibrillation was not observed.

"These findings emanate from institutions that together provide a very high rate of mitral valve repair (>90 percent) with low operative mortality, emphasizing that such results might also be achieved in routine practice at many advanced repair centers," the authors write. "The advantages associated with early surgical correction of mitral valve regurgitation were confirmed in both unmatched and matched populations, using multiple statistical methods."


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