Clinical Characteristics and Outcomes of Patients with Acute Coronary Syndrome and Prior Coronary Artery Bypass Grafting in a Large Middle Eastern Cohort

BACKGROUND Acute Coronary Syndrome (ACS) can occur in patients with prior coronary artery bypass grafting (CABG). In the Gulf Registry of acute coronary events (Gulf RACE), we identified the clinical characteristics and in-hospital outcomes of these patients. METHODS Clinical characteristics and in-hospital outcomes for 461 ACS patients with prior CABG are compared to 7715 ACS patients without prior CABG enrolled from 64 hospitals in 6 Gulf countries over a 6-month period. RESULTS The overall incidence of ACS with prior CABG was 5.6% out of 8176 patients. The ACS with prior CABG were older (63 vs 55 years, P<0.0001), had more history of diabetes (62.3 vs 37.6%, P <0.0001), dyslipidemia (70.3 vs 29.5%, P<0.0001), and hypertension (75.7 vs 47.8%, P<0.0001) compared with the non-CABG group. They presented more frequently with dyspnea (14.8 vs 9.5%, P<0.0005), non-ST segment elevation myocardial infarction (41.4 vs 31.6%, P<0.0001) and echocardiographic evidence of left ventricular dysfunction (49.4 vs 29.8%, P<0.0001) than ACS without prior CABG. They had a complicated in-hospital course with more recurrent ischemia (13.9 vs 9.3%, P=0.0011), heart failure (24.1 vs 15.7%), and stroke (2.2 vs 0.6%) compared with those without CABG. The in-hospital mortality rate was 5.6% in the CABG group compared with 3.5% in the ACS without prior CABG group. After adjusting for confounders, prior CABG was independently associated with recurrent ischemia and shock, more in patients presenting with ST elevation than non-ST elevation ACS. CONCLUSIONS Patients with ACS and prior CABG are a high-risk group with poor outcomes irrespective of their older age and comorbidities. They should be identified and treated differently to improve their outcomes.