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[Coronary bypass surgery within thirty days of acute inferior myocardial infarction]
M Matsumoto1, Y Konishi, K Minakata
1Department of Cardiovascular Surgery, Japanese Red Cross Society, Wakayama Medical Center, Japan.
Insights
Patients undergoing coronary artery bypass grafting after acute myocardial infarction, particularly inferior MIs, face a high risk of complete atrioventricular block and increased mortality. Early surgery (within 48 hours) showed similar mortality, but delayed surgery (48 hours to 30 days) had significantly different outcomes.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Cardiac Electrophysiology
Context:
- Coronary artery bypass grafting (CABG) is a critical intervention for acute myocardial infarction (AMI).
- The timing and location of the infarct-related artery influence surgical outcomes and complications.
- Postoperative atrioventricular (AV) block is a known complication of cardiac surgery.
Purpose:
- To compare outcomes of isolated CABG in patients with proximal right coronary artery (inferior MI) versus left coronary artery occlusions within 30 days of AMI.
- To investigate the incidence of complete AV block and associated mortality in these patient groups.
- To evaluate the impact of surgical timing (within 48 hours vs. 48 hours to 30 days post-MI) on mortality.
Summary:
- This study analyzed 82 patients undergoing isolated CABG within 30 days of AMI, comparing those with proximal right coronary artery (Group 1) versus left coronary artery (Group 2) infarcts.
- Group 1 patients more frequently had three-vessel or left main disease and experienced a higher incidence of postoperative complete AV block (30% vs. 6%) compared to Group 2.
- While early surgery (within 48 hours) showed similar mortality, delayed surgery (48 hours to 30 days) had significantly different mortality rates (22% vs. 0%), with complete AV block leading to high mortality (38% in Group 1, 67% in Group 2).
Impact:
- Patients undergoing CABG for inferior MIs are at significant risk for postoperative complete AV block, a complication strongly associated with increased mortality.
- The findings highlight the importance of considering infarct location and potential for AV block when planning CABG post-MI.
- Optimal timing for CABG after AMI requires further investigation to mitigate risks associated with delayed intervention and specific infarct-related arteries.
Abstract:
Between April 1988 and November 1998, 82 patients underwent isolated coronary artery bypass grafting within 30 days of acute myocardial infarction. The infarct-related artery was the proximal right coronary artery (27 patients; group 1) and the left coronary artery (55 patients; group 2). In group 2 the infarct-related artery was the left main coronary artery (8 patients), the left anterior descending coronary artery (33 patients), and the left circumflex coronary artery (14 patients). There was no difference between groups 1 and 2 with regard to sex, age (65 +/- 9 vs 66 +/- 10, respectively), presence of diabetes, renal insufficiency, previous myocardial infarction, and preoperative use of an intraaortic balloon pump (67% vs 71%, respectively). Compared with group 2, group 1 patients more often had three-vessel or left main disease (93% vs 65%, respectively; p = 0.018), a higher number of bypass grafts (3.0 +/- 0.8 vs 2.5 +/- 0.7, respectively; p = 0.014), and a greater incidence of postoperative complete atrioventricular (AV) block (30% vs 6%, respectively; p = 0.005). The hospital mortality rate for patients who underwent surgery within 48 hours after acute myocardial infarction did not differ between groups 1 and 2 (22% vs 18%, respectively). However, patients in both groups who underwent surgery between 48 hours and 30 days after infarction had significantly different mortality rates (22% vs 0%, respectively; p = 0.037). Patients with postoperative complete AV block had high mortality rates of 38% in group 1 and 67% in group 2. We conclude that patients who undergo coronary bypass surgery within 30 days of acute inferior myocardial infarction have a high incidence of postoperative complete AV block, which result in increased mortality.