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The impact of coronary artery bypass on late myocardial infarction
Insights
Coronary artery bypass surgery shows a low rate of late myocardial infarction. This study followed 200 patients, finding that surgical management of angina pectoris is associated with favorable long-term cardiac outcomes.
Area of Science:
- Cardiology
- Cardiac Surgery
- Preventive Cardiology
Background:
- Coronary artery bypass grafting (CABG) is a common surgical intervention for coronary artery disease.
- Understanding long-term outcomes, particularly myocardial infarction (MI) rates, is crucial for patient management.
- Previous studies have varied in their reporting of perioperative and late MI following CABG.
Purpose of the Study:
- To assess the incidence of perioperative and late myocardial infarction in patients undergoing CABG.
- To evaluate the overall cumulative myocardial infarction rate up to 43 months post-surgery.
- To determine the impact of CABG on long-term cardiac health in patients with stable and unstable angina pectoris.
Main Methods:
- Prospective follow-up of 200 consecutive patients undergoing CABG for angina pectoris.
- Serial electrocardiogram (ECG) analysis (preoperative, early postoperative, late) over a mean follow-up of 18.5 months.
- Definition of myocardial infarction based on new significant Q waves (Minnesota Code).
Main Results:
- Operative mortality was low at 0.5% (1/200).
- Perioperative myocardial infarction occurred in 8.5% (17/200) of patients.
- The 43-month cumulative myocardial infarction rate, including perioperative and late events, was 14%.
Conclusions:
- Surgical management of angina pectoris via CABG is associated with a low late myocardial infarction rate.
- The study demonstrates favorable long-term cardiac event rates in patients who have undergone CABG.
- Disappearance of Q waves post-discharge suggests potential for myocardial recovery or improved ECG findings after surgery.
Abstract:
Two hundred consecutive patients undergoing coronary artery bypass for stable and unstable angina pectoris were followed clinically 3 to 53 months (mean 27) and with serial electrocardiograms (ECG's) 3 to 43 months (mean 18.5) postoperatively. Complete (twelve lead) resting ECG data including preoperative, early postoperative (in hospital), and late (post hospital) studies were available in 98 per cent (196/199) of hospital survivors. A total of 2,304 ECG's were examined by two cardiologists for a total follow-up of 3,629 patient months. Myocardial infarction was defined as the appearance of a new, significant (Minnesota Code) Q wave. Fifty-four per cent (108/200) had triple vessel disease and 24 per cent (47/200) preinfarction angina pectoris by strict criteria. There was one hospital death for an operative mortality of 0.5 per cent (1/200). There was one late fatal and three late nonfatal myocardial infarctions. Seventeen patients developed new Q waves in the early postoperative period, a perioperative infarction rate of 8.5 per cent (17/200). The 43 month cumulative myocardial infarction rate, including all early and late postoperative new Q waves and three late deaths from cardiac disease, was 14 per cent. Twenty-two per cent (20/91) showed disappearance of Q waves present at the time of hospital discharge. These data suggest that the late myocardial infarction rate is low in surgically managed patients.