Outcomes of management strategies in patients with prior coronary artery bypass grafting presenting with an acute coronary syndrome.

Background: Patients with prior coronary artery bypass grafting (CABG) presenting with an acute coronary syndrome (ACS) have poor outcomes and the optimal treatment strategy for this population is unknown.

Methods: Using linked administrative databases, we examined patients with an ACS between 2008 and 2019, identifying patients with prior CABG. Patients were categorized by ACS presentation type and treatment strategy. Our primary outcome was the composite of death and recurrent myocardial infarction at one year.

Results: Of 54,641 patients who presented with an ACS, 1670 (3.1%) had a history of prior CABG. Of those, 11.0% presented with an ST-elevation myocardial infarction (STEMI) of which, 15.3% were treated medically, 31.1% underwent angiography but were treated medically, 22.4% with fibrinolytic therapy and 31.1% with primary PCI. The primary outcome rate was the highest (36.8%) in patients who did not undergo angiography and was similar in the primary PCI (20.8%) and fibrinolytic group (21.9%). In patients presenting with a non-ST elevation acute coronary syndrome (NSTE-ACS) (89.0%), 33.2% were treated medically, 38.5% underwent angiography but were treated medically and 28.2% were treated with PCI. Compared to those who underwent PCI, patients treated conservatively demonstrated a higher risk of the composite outcome (14.8% vs 27.3%; adjusted hazard ratio 1.70, 95% confidence interval 1.22-2.37).

Conclusions: Patients with prior CABG presenting with an ACS are often treated conservatively without PCI, which is associated with a higher risk of adverse events.