Outcomes of emergency coronary angiography after cardiac surgery

Perioperative myocardial infarction (PMI) is a serious complication after cardiac surgery with an estimated incidence of 1–10%. It is associated with increased inhospital morbidity and mortality. The subtle and challenging presentation of PMI often requires rapid and effective diagnostic and therapeutic interventions, to salvage the ischaemic myocardium, protect from endothelial dysfunction and preserve cardiac function. Emergency coronary angiography (ECA) has emerged as a safe and effective tool to identify PMI in post coronary artery bypass graft (CABG) patients with haemodynamic instability. However, its role in other cardiac surgeries is unclear. It should be emphasized that ECA after cardiac surgery procedure is performed in patients in a critical condition, which increases the risk of cardiac and non-cardiac complications, including sudden cardiac arrest, bleeding, acute kidney injury and others. We report our institutional experience of performing ECA in patients with haemodynamic instability or suspected myocardial ischaemia within 24 h after cardiac surgery. Out of 11,537 consecutive cardiac surgeries performed at our institution over a five year period, 115 patients (1.19%) underwent ECA during the early postoperative period of 24 h after cardiac surgery. Cardiac surgeries were performed using standard operative techniques. ECA was performed during the early post operative period if the patient had any of the following criteria: new unexplained haemodynamic collapse, malignant ventricular arrhythmias, sudden cardiac arrest, persistent ST-segment changes on electrocardiogram (ECG), elevation in high-sensitivity cardiac troponin T, ck-MB levels or new regional wall motion abnormalities on 2D-transthoracic echocardiogram or any other clinical findings suggestive of myocardial ischaemia. ECA was deferred if acceptable haemodynamic stability could not be maintained despite maximal medical therapy. ECAs were performed in a standardized way by a cardiologist. After the ECA patients were transferred to the cardiothoracic surgery intensive care unit. The decision to pursue percutaneous versus surgical revascularization was left to the discretion of physicians based on the results of ECA. The chi-square test was used for categorical variables. Associations between non-parametric and parametric variables were assessed by Spearman’s and Pearson’s tests, respectively. Multiple logistic regression was used to identify the predictors of in-hospital mortality in the ECA cohort. A two sided alpha (p value) of less than 0.05 was considered statistically significant. In-hospital mortality was defined as any death that occurred during the same hospital admission corresponding to cardiac surgery. The ECA cohort was composed of 66.2% males and a mean (SD) age of 65.9 11.4 years. Coronary artery disease (CAD) (80.1%) and hypertension (78.8%) were the most common comorbidities. Sixty per cent had prior myocardial infarction and 31.2% had prior percutaneous coronary intervention (PCI). The most common indication for ECA was haemodynamic instability (35%) followed by ECG changes (25%), cardiac arrest (23%), troponins elevation (8%) and miscellaneous causes (9%). The most common finding on ECA was graft failure (31.3%) followed by coronary artery occlusion (7.8%), coronary artery embolism (7.0%), coronary artery spasm (4.3%), extrinsic compression (2.6%), diffuse