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Timing of coronary artery bypass grafting after acute myocardial infarction
H Wasvary1, F Shannon, J Bassett
1Department of General Surgery, William Beaumont Hospital, Royal Oak, Michigan 48073, USA.
Insights
Timing of coronary artery bypass grafting (CABG) after acute myocardial infarction (AMI) did not significantly impact hospital mortality. Factors like low ejection fraction and cardiogenic shock were more critical predictors of patient outcomes.
Area of Science:
- Cardiology
- Cardiac Surgery
Background:
- The optimal timing for coronary artery bypass grafting (CABG) following an acute myocardial infarction (AMI) is a subject of ongoing debate.
- Patients often require urgent surgical intervention for complications like postinfarction angina or complex coronary anatomy.
Purpose of the Study:
- To investigate the relationship between the time interval from acute myocardial infarction (AMI) to coronary artery bypass grafting (CABG) and operative mortality.
- To identify preoperative factors influencing hospital mortality in patients undergoing CABG after AMI.
Main Methods:
- Retrospective analysis of 423 patients who underwent CABG within 21 days of AMI between 1992 and 1995.
- Statistical evaluation of various preoperative parameters, including patient demographics, cardiac condition, and surgical indications.
Main Results:
- Operative mortality rates varied across different time intervals from AMI to CABG, but the overall interval did not significantly impact patient outcomes.
- Factors significantly associated with increased hospital mortality included ejection fraction < 30%, age > 70 years, cardiogenic shock, and cardiac index < 1.5.
- Cardiac index was identified as the most significant predictor of mortality (P < 0.001).
Conclusions:
- The timing of CABG within three weeks of AMI does not appear to independently affect hospital mortality in symptomatic patients.
- Preoperative patient factors, particularly cardiac function and hemodynamic stability, are more crucial determinants of surgical outcomes after AMI.
Abstract:
Appropriate timing for coronary artery bypass grafting (CABG) after acute myocardial infarction (AMI) remains controversial. We retrospectively examined 423 patients who underwent CABG within 21 days of an AMI between 1992 and 1995, mainly for postinfarction angina and complex anatomy. The operative mortality rates associated with increasing time intervals between AMI and CABG were 17.4, 9.1, 4.0, and 5.8 per cent, for less than 6 hours, 6 to 24 hours, 1 to 7 days, and 7 to 21 days, respectively. There were 25 (5.9%) deaths overall. Statistical analysis was performed to evaluate the following preoperative parameters: age, sex, reoperation, previous myocardial infarction (MI), MI type and location, anatomy, cardiogenic shock, unstable angina, ventricular arrhythmias, extending MI, ejection fraction, indications for surgery, cardiac index, and interval from infarction to CABG. Interval between operation and AMI did not have a significant impact on patient outcome. Factors associated with an increased hospital mortality were ejection fraction < 30 per cent, age > 70 years, presence of cardiogenic shock, and cardiac index < 1.5. Only cardiac index proved to be a significant predictor of mortality (P < 0.001). We conclude that the timing of CABG, in and of itself, has no significant effect on hospital mortality of symptomatic patients within 3 weeks of AMI.