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Predicting Operative Risk During Coronary Revascularization

Although operative mortality and morbidity from coronary artery bypass grafting have decreased dramatically over the last 20 years, patients with moderate-to-severe left ventricular (LV) dysfunction remain at high risk. Many who would have died from an MI now survive and require definitive surgical revascularization. In this retrospective study from the Toronto Hospital, researchers identified independent predictors of operative mortality for 20,614 consecutive patients who underwent isolated CABG between 1982 and 1997.

Twenty percent of patients had moderate LV dysfunction (ejection fraction, 20 percent to 40 percent) and 3.3 percent had severe LV dysfunction (ejection fraction, less than 20 percent). Those with worse LV function were more likely to be male and have more extensive coronary disease or left main stenosis but less likely to receive an internal thoracic artery graft. Independent predictors of mortality for the entire cohort were reoperation (risk ratio, 2.87), female sex (RR, 1.75), advanced LV dysfunction (RR, 1.7), left main coronary stenosis (RR, 1.61), urgent operation (RR, 1.54), increased age (RR, 1.05), and earlier year of surgery (RR, 0.91). For severe LV dysfunction, the only significant independent predictors were urgent surgery and reoperation.

Comment: The percentage of patients with moderately impaired LV function undergoing CABG has risen during the past 15 years while operative mortality has declined. This study identified useful predictors of operative mortality for patients with normal or moderately impaired LV function. Unfortunately, patients with severe LV dysfunction represented less than 5 percent of the study population, but their mortality rate was 4-fold higher (8 percent vs. 2 percent for those with preserved LV function). Future studies should focus on more accurate risk stratification and management strategies for this high-risk population.

— GW Dec

Published in Journal Watch Cardiology January 21, 2000

Citation(s):

Yau TM et al. Predictors of operative risk for coronary bypass operations in patients with left ventricular dysfunction. J Thorac Cardiovasc Surg 1999 Dec 118 1006-1013.

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