The optimal timing for coronary artery bypass grafting after acute myocardial infarction is not well established. The California Discharge Database facilitates the study of this issue by providing data from a large patient cohort free of institutional bias. We examine the timing of coronary artery bypass grafting after acute myocardial infarction on short-term outcomes.
Methods
We reviewed California Discharge Data to identify 40,159 patients who were hospitalized for acute myocardial infarction (day 0) and underwent subsequent coronary artery bypass grafting. Patients were stratified by the timing of coronary artery bypass grafting to “early” (days 0–2) and “late” groups (day 3 or later). The primary outcome variable was all-cause hospital mortality. Multiple logistic and linear regression and propensity analyses assessed the risk of adverse events, controlling for factors associated with preoperative clinical acuity, including the Charlson Comorbidity Index, shock, mechanical ventilation, and the use of intra-aortic balloon counterpulsation.
Results
Of 9476 patients identified, 4676 (49%) were in the early coronary artery bypass grafting group and 4800 (51%) were in the late coronary artery bypass grafting group. A total of 444 patients (4.7%) died during hospitalization, with a peak mortality rate of 8.2% among patients undergoing coronary artery bypass grafting on day 0, declining to a nadir of 3.0% among patients undergoing coronary artery bypass grafting on day 3. The mean time to coronary artery bypass grafting was 3.2 days. Patients undergoing early coronary artery bypass grafting experienced a higher mortality rate than those undergoing late coronary artery bypass grafting (5.6% vs 3.8%, P < .001). Early coronary artery bypass grafting was an independent predictor of mortality after controlling for clinical acuity and on propensity analysis (odds ratio 1.43, P = .003).
Conclusion
Patients undergoing coronary artery bypass grafting within 2 days of hospitalization for acute myocardial infarction experienced higher mortality rates than those undergoing coronary artery bypass grafting 3 or more days after acute myocardial infarction, independently of clinical acuity. This suggests that coronary artery bypass grafting may best be deferred for 3 or more days after admission for acute myocardial infarction in nonurgent cases.
CTSNet classification
20
23
Abbreviations and Acronyms
AMI
acute myocardial infarction
CABG
coronary artery bypass graft
IABP
intra-aortic balloon pump
ICD-9-CM
International Classification of Diseases, Ninth Revision, Clinical Modification
OR
odds ratio
PCI
percutaneous coronary intervention
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Presented at the 33rd Annual Meeting of the Western Thoracic Association, June 27 to 30, Santa Anna Pueblo, New Mexico, Sampson Award Finalist.