Early Postoperative Complications in Patients with Acute Myocardial Infarction During Emergency Coronary Bypassing

Abstract

Despite the success results of interventional cardiology, the indications for coronary artery bypass grafting in acute myocardial infarction, according to the recommendations, are quite limited. In recent years, the optimization of perioperative management of patients, including myocardial protection, has helped to improve the effects of treatment by emergency surgical revascularization in patients with cardiogenic shock. Thus, it is important to learn the results of emergency surgical myocardial revascularization in patients with acute myocardial infarction (AMI), which were previously considered incurable or in cases where interventional cardiology is ineffective. Therefore, the aim of the study was to conduct a prospective analysis of the immediate clinical results of the early postoperative period to determine the factors of early mortality in emergency coronary artery bypass grafting. Research methods. The research is based on the prospective investigation of 129 patients who were hospitalized in Kyiv “Heart Center” through the period from 2011 to 2015. At 100,0% the ST-elevated myocardial infarction (STEMI) of them it was verified, at 29,0 patients non- ST-elevated myocardial infarction (NSTEMI) was set. In early postoperative period, we have analyzed such events like inotropic support duration, necessity of intra-aortic balloon pump, the episodes of the development kidney injury and respiratory failure, complete atrioventricular blockade, supraventricular tachyarrhythmia episodes, encephalopathy, rethoracotomy needs. Also early postoperative mortality endpoints were evaluated. Research results. It has been proven that in the presence of STEMI type of acute myocardial injury compared with NSTEMI type, there is a higher risk of acute left ventricular failure (p <0.05) followed by intra-aortic balloon pulsation (IABP)- procedure (p <0,05) and inotropic support (p <0,05) in the early postoperative period. In patients of the STEMI group, acute kidney injury was recorded more often with reliable indexes of absolute and relative risks (p <0,05). All cases of transient atrioventricular block after emergency coronary artery bypass grafting (CABG) were registered in patients with STEMI injury with significant changes of odds ratio (p <0.05). It was established that the main structure of respiratory complications was due to prolonged mechanical ventilation, but the difference in the relative risk and odds ratio between the STEMI and NSTEMI groups is insignificant (p> 0.05), however the likelihood of supraventricular arrhythmia and encephalopathy in the NSTEMI group was reliably higher (p <0.05). Estimates of the level of early postoperative mortality (12.4%) proved the probable relative risk (p <0.05) and the odds ratio (p <0.05) of mortality in the STEMI group, which was confirmed by the analysis of cumulative survival by Kaplan-Meyer method (Criterion log-rank 2,74; p = 0,006). Mortality in the STEMI group was associated with previously diagnosed acute heart failure (56,2%), the onset of cardiogenic shock (31,3%) and the development of acute mitral regurgitation (12.5%). Conclusions. STEMI type of acute myocardial damage installed reliably higher absolute and relative risk of acute left ventricle failure (p<0,05) with following intra-aortic balloon pump (p<0,05), inotropic support (p<0,05) and acute kidney injury with glomerular rate reduction (p<0,05) in the early postoperative period. The higher absolute and relative risks of encephalopathy, as well as the possibility of supraventricular arrhythmia presented at NSTEMI patients (p<0,05). All cases of transient atrioventricular blockade and early hospital mortality with reliable odds ratio, absolute and relative risks changes registered at STEMI patients (p<0,05). Prospects for further research are long-term prospective observation, analysis of long-term clinical results of coronary artery bypass grafting in patients with acute myocardial infarction, as well as assessment of risk factors for long-term mortality.