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Optimal timing of coronary artery bypass graft surgery after acute myocardial infarction
J H Braxton1, G L Hammond, G V Letsou
1Section of Cardiothoracic Surgery, Yale University School of Medicine, New Haven, Conn 06520, USA.
Insights
For acute myocardial infarction (AMI) patients, coronary artery bypass graft surgery (CABG) timing is crucial. Non-Q-wave infarction patients can have CABG anytime, while Q-wave infarction patients should wait over 48 hours for safer outcomes.
Area of Science:
- Cardiology
- Cardiac Surgery
- Cardiovascular Research
Background:
- Optimal timing for coronary artery bypass graft surgery (CABG) after acute myocardial infarction (AMI) remains a critical clinical question.
- Previous studies have not clearly defined the risks associated with early revascularization post-infarction.
- This study aims to assess the impact of time from infarction to CABG on patient outcomes.
Purpose of the Study:
- To determine the optimal timing for CABG in patients who have experienced an acute myocardial infarction (AMI).
- To evaluate the risks associated with early versus delayed CABG after different types of myocardial infarction (MI).
Main Methods:
- Retrospective review of 116 patients undergoing CABG within 6 weeks of MI (Jan 1991-Jul 1992).
- Patients were divided into groups based on time from MI to revascularization: within 48 hours, 3-5 days, and after 5 days.
- Comparison with a control group of 255 patients undergoing CABG for refractory angina without recent MI.
Main Results:
- All patients undergoing CABG post-MI showed increased risk of requiring intra-aortic balloon pump, vasopressors, and perioperative MI compared to controls.
- Surgical mortality was highest immediately following Q-wave infarctions.
- Patients with non-Q-wave MI and those with Q-wave MI revascularized after 48 hours had comparable outcomes to controls.
Conclusions:
- Coronary artery bypass graft surgery (CABG) can be performed relatively safely at any time for patients with non-Q-wave infarction.
- For patients with Q-wave infarction, delaying CABG until after 48 hours post-MI is recommended for improved safety.
Background:
To assess optimal timing for coronary artery bypass graft surgery (CABG) after an acute myocardial infarction (AMI), all patients undergoing CABG without associated procedures at our institution from January 1, 1991, to July 30, 1992, were reviewed. Patients were divided into three groups based on time from infarct to revascularization. The control group consisted of patients operated on for angina refractory to medical management. Relative risks (incident infarction group divided by incident control group) were established for need of vasopressors, new balloon to separate from bypass, perioperative myocardial infarction, and hospital mortality.
Methods And Results:
One hundred sixteen patients underwent CABG within 6 weeks of infarction. In the experimental group, 58 patients underwent CABG for non-Q-wave infarction, and 58 patients underwent CABG for Q-wave infarction. In the control group, 255 patients underwent surgery for angina without infarction. Patients were analyzed by group relative to the time between infarction and CABG. Patients were analyzed between infarction and CABG and assigned to one of three groups. Group 1 patients were revascularized within 48 hours; group 2, between 3 and 5 days; and group 3, after 5 days. Significance was determined by Fisher's exact or Mantel-Haenszel chi 2 test where appropriate. Multivariate analysis was performed on statistics that were significant. All patients within all groups after Q-wave or non-Q-wave myocardial infarction had a significantly higher risk of needing an intra-aortic balloon pump and vasopressors to be weaned from bypass and a greater incidence of perioperative MI compared with control patients. Surgical mortality is highest immediately after Q-wave infarctions.
Conclusions:
Patients with non-Q-wave infarction may undergo CABG relatively safely at any time. Acceptable timing for CABG after Q-wave infarction is after 48 hours.