Predictors and outcomes of early coronary angiography in patients with prior coronary artery bypass surgery presenting with non-ST elevation myocardial infarction

Abstract

Introduction: The best strategy in patients with prior coronary artery bypass graft surgery (CABG) who present with non-ST elevation myocardial infarction (NSTEMI) remains less well defined. We compare the characteristics, therapeutic interventions and outcomes of patients with prior CABG presenting with NSTEMI. Methods: All patients who presented to our hospital during 2007-2012 with available electronic records were analysed retrospectively. Outcomes were compared between patients who underwent coronary angiography or percutaneous coronary intervention (PCI) versus those who were treated medically. Results: A total of 117 patients were analysed. Of that, 79 patients were managed medically while 38 underwent early angiography, of which only 11 (9.5%) received PCI. Patients treated medically (did not undergo angiography) were older (74±10 vs70±8; p=0.05). ECG changes were the only independent predictor for early angiography (OR 0.4, 95% CI 0.15 to 0.99; p=0.05) while recurrent chest pain (OR 0.2, 95% CI 0.05 to 0.97; p=0.05) predicted PCI on multivariate analysis. The PCI group had higher Global Registry of Acute Cardiac Events (GRACE) score (176±29 vs 150±31; p=0.01). No significant difference was found in readmission rates, morbidity (unstable angina pectoris, NSTEMI, ST elevation myocardial infarction (STEMI), or combination) or mortality at 12 months between the groups who underwent angiography, PCI, or treated medically on univariate and multivariate analysis. Conclusions: The opportunity to intervene in prior CABG patients presenting with NSTEMI is often low. Initial medical management may be a reasonable option in carefully selected patients particularly in the absence of ongoing symptoms, ECG changes or very high GRACE scores. Further studies are required to evaluate the safety of non-invasive strategies in managing this population.