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Coronary artery bypass for recent infarction. Predictors of mortality
K S Naunheim1, K A Kesler, K R Kanter
1Department of Surgery, St. Louis University Medical Center, Missouri.
Insights
Coronary artery bypass (CAB) surgery after myocardial infarction is controversial. Advanced age, poor left ventricular function, and clinical group independently predict mortality in these high-risk patients.
Area of Science:
- Cardiology
- Cardiac Surgery
- Interventional Cardiology
Background:
- The optimal timing and role of coronary artery bypass (CAB) surgery following myocardial infarction (MI) are debated.
- Recent MI patients undergoing CAB surgery represent a high-risk population with variable outcomes.
Purpose of the Study:
- To evaluate the operative risks and identify predictors of mortality in patients undergoing isolated CAB surgery within 30 days of MI.
- To stratify risk based on clinical presentation and patient characteristics.
Main Methods:
- A retrospective review of 336 patients who underwent isolated CAB surgery within 30 days of MI.
- Patients were categorized into four clinical groups based on angina severity and hemodynamic status.
- Multivariate logistic regression analysis was used to identify independent predictors of mortality.
Main Results:
- Overall mortality was 7.7%, with significant variation across clinical groups (2.3% to 47.8%).
- Independent predictors of mortality included advanced age (p=0.002), left ventricular wall-motion score (p=0.004), and clinical group (p=0.048).
- Variables such as interval from infarction to CAB, number of diseased vessels, and bypass times were not independent predictors.
Conclusions:
- CAB surgery in the early post-MI period carries significant risk, particularly in patients with severe ischemia or cardiogenic shock.
- Risk stratification using clinical presentation, age, and left ventricular function is crucial for patient selection and management.
- Further research is warranted to refine patient selection criteria and optimize outcomes for this vulnerable population.
Abstract:
The role of coronary artery bypass (CAB) surgery in patients with recent myocardial infarction remains controversial. To more clearly define the operative risks, we reviewed 336 patients who underwent isolated CAB within 30 days of infarction. There were 129 patients with stable or no angina (Group 1), 163 with angina at rest (Group 2), 21 with angina requiring intra-aortic balloon counterpulsation for pain control (Group 3), and 23 with severe postinfarction ischemia or extension complicated by cardiogenic shock (Group 4). There were 26 (7.7%) deaths overall. The mortality was 2.3% in Group 1, 6.1% in Group 2, 9.5% in Group 3, and 47.8% in Group 4. Univariate analysis (Student's t and chi 2 tests) and multivariate analysis (stepwise logistic regression model) were performed on 17 variables: age, gender, clinical Group (1-4), number of diseased vessels, presence of left main artery disease, left ventricular wall-motion score, left ventricular end-diastolic pressure, presence of mitral insufficiency, extent of infarction (subendocardial vs. transmural), interval from infarction to CAB, number of distal anastomoses performed, preoperative hemodynamic status, aortic cross-clamp time, and total cardiopulmonary bypass time. Only advanced age (p = 0.002), left ventricular wall-motion score (p = 0.004), and clinical group (p = 0.048) proved to be independent predictors of mortality by multivariate analysis.(ABSTRACT TRUNCATED AT 250 WORDS)