Introduction:
Primary percutaneous coronary intervention (PCI) is the standard reperfusion strategy for ST-elevation myocardial infarction (STEMI). However, contemporary real-world outcomes of de novo PCI in older adults with a history of coronary artery bypass grafting (CABG) are not well described. We compared in-hospital outcomes and 30-day readmissions after STEMI-related de novo PCI among older patients with and without prior CABG.

Material and methods:
Using the Nationwide Readmissions Database (2016–2022), we identified patients aged ≥ 65 years hospitalized with a primary diagnosis of STEMI who underwent de novo PCI. Patients were stratified by prior CABG status. Multivariable logistic regression assessed in-hospital adverse events (including mortality). Among survivors, Cox proportional hazards models were used to evaluate 30-day all-cause readmissions.

Results:
Among 194,958 patients, 9,929 (5.09%) had prior CABG, and 185,029 (94.91%) did not. After adjustment, prior CABG was associated with lower odds of acute kidney injury (AKI), cardiac arrest, cardiogenic shock, and vasopressor use. There were no significant differences in mechanical circulatory support, AKI requiring hemodialysis, ischemic stroke, hemorrhagic stroke, or in-hospital mortality. Among survivors, 30-day readmissions were more frequent among patients with prior CABG (12.79% vs. 10.48%; HR = 1.145, 95% CI: 1.021–1.217; p = 0.015). Mean time to readmission was similar (10.66 vs. 10.54 days; p = 0.757).

Conclusions:
In older STEMI patients undergoing de novo PCI, prior CABG was associated with similar in-hospital mortality and fewer in-hospital adverse events, but higher 30-day readmission risk. These findings suggest that while prior CABG may not worsen immediate outcomes, it identifies patients who may benefit from enhanced post-discharge follow-up and transitional care.