Misguided Use of Multivariable Analysis to Study Primary Percutaneous Coronary Intervention in Patients With Prior Coronary Artery Bypass Graft

Comparison of Outcomes of Patients with vs without Previous Coronary Artery Bypass Graft Surgery Presenting with ST-Segment Elevation Acute Myocardial Infarction

The outcomes of patients with previous coronary bypass graft surgery (CABG) presenting with ST-segment elevation acute myocardial infarction (STEMI) have received limited study. We compared the clinical and procedural characteristics and outcomes of STEMI patients with and without previous CABG in a contemporary multicenter STEMI registry between 2003 and 2020. The primary outcomes of the study were mortality and major cardiac adverse events (MACE: death, MI or stroke). Survival curves were derived using the Kaplan-Meier method and compared with the log-rank test. Of the 13,893 patients included in the analyses, 7.2% had previous CABG. Mean age was 62.4 ± 13.6 years, most patients (71%) were men and 22% had diabetes. Previous CABG patients were older (69.0 ± 11.7 vs 61.9 ± 13.6 years, p <0.001) and more likely to have diabetes (40% vs 21%, p <0.001) compared with patients without previous CABG. Previous CABG patients had higher mortality and MACE at 5 years (p <0.001). Outcomes were similar with saphenous vein graft vs native coronary culprits. Previous CABG remained associated with mortality from discharge to 18 months (p = 0.044) and from 18 months to 5 years (p <0.001) after adjusting for baseline characteristics. Long term outcomes after STEMI were worse among patients with previous CABG compared with patients without previous CABG, even after adjustment for baseline characteristics.

Characteristics and Long-Term Outcomes of Patients With Prior Coronary Artery Bypass Grafting Undergoing Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction

Limited data are available on characteristics and long-term outcomes of patients with coronary artery bypass grafts (CABG) undergoing primary percutaneous coronary intervention for ST-elevation myocardial infarction (STEMI). Between January 2000 to December 2014, we identified STEMI patients with prior CABG undergoing primary percutaneous coronary intervention from 3 sites. Kaplan-Meier methods to estimate survival and major adverse cardiac events (MACE) were employed and compared to a propensity matched cohort of non-CABG STEMI patients. Independent predictors of outcomes were analyzed with Cox modeling. Of the 3,212 STEMI patients identified, there were 296 (9.2%) CABG STEMI patients, having nearly similar frequencies of culprit graft (47.6%) versus culprit native (52.4%) as the infarct-related artery (IRA). At 10 years, the adjusted survival was 44% in CABG STEMI versus 55% in non-CABG STEMI (HR 1.26; 95%CI 0.86 to 1.87; p = 0.72). Survival free of MACE was lower for CABG STEMI (graft IRA, 37%; native IRA, 46%) as compared to non-CABG STEMI controls (63%) (p = 0.02). Neither CABG history nor IRA (native vs graft) was independently associated with death or MACE in multivariable analysis. Temporal trends showed no significant change in death or MACE rates of CABG STEMI patients over time. In conclusion, long term survival of CABG STEMI patients is not significantly different than matched STEMI patients without prior CABG; however, CABG STEMI patients were at significantly higher risk for MACE events.