Prophylactic intra-aortic balloon counterpulsation before surgical myocardial revascularization in patients with acute myocardial infarction.

INTRODUCTION: Prophylactic intra-aortic balloon counterpulsation (pIABC) is recommended for high-risk patients undergoing coronary artery bypass grafting (CABG) surgery. Criteria for high-risk patients benefiting from pIABC are unclear. This study aimed to specifically describe the effect of pIABC on outcomes of patients with acute myocardial infarction (AMI) undergoing CABG. METHODS: In 178 of 484 AMI patients (non-ST-segment elevation myocardial infarction [NSTEMI] or ST-segment elevation myocardial infarction [STEMI] ≤5 days before surgery) without cardiogenic shock who underwent CABG between 2008 and 2013, pIABC was initiated preoperatively. After propensity score matching, the outcomes of 400 patients were analyzed (pIABC: 150; Control: 250). RESULTS: After propensity score matching, baseline and operative characteristics were balanced between the groups except for a higher rate of patients with a left ventricular ejection fraction (LVEF)≤30% in the pIABC group (26% vs. Control: 13%; p=0.032). Seven point two percent (7.2%) of the control patients received an IABP intraoperatively or postoperatively. Postoperative extracorporeal life support (ECLS) was only needed in the control group (1.2% vs. 0%; p=0.01). Postoperative plasma curves of troponin I, creatine kinase (CK) and creatine kinase isoform MB (CK-MB) levels were reduced in the pIABC group compared with the control group. In-hospital mortality was reduced in the pIABC group (3.3% vs. control: 6.4%; p=0.18). After multivariate adjustment for other preoperative risk factors, pIABC was significantly protective concerning in-hospital mortality (HR 0.56; 95%-CI 0.023-0.74; p=0.021). Mortality (pIABC vs. control) was more affected in patients with preoperative LVEF≤30% (2/36 (5.6%) vs. 6/31 (19%); heart rate (HR) 0.25; 95%-CI 0.046-1.3; p=0.13) compared with LVEF>30% (3/114 (2.6%) vs. 10/219 (4.6%); HR 0.56; 95%-CI 0.15-2.1; p=0.55). Long-term survival did not differ between the groups. CONCLUSIONS: pIABC in CABG for AMI is associated with reduced perioperative cardiac injury and in-hospital mortality. Long-term survival is not affected.

Total arterial revascularization in patients with acute myocardial infarction - feasibility and outcomes.

BACKGROUND: In acute situations such as acute myocardial infarction (AMI) with indication for coronary artery bypass grafting (CABG), total arterial revascularization (TAR) is often rejected in favour of saphenous vein (SV) grafting, which is assumed to allow for quicker vessel harvesting, a simpler anastomosis technique, and thus quicker revascularization and fewer bleeding complications. The aim of this study was to evaluate whether reluctance to apply TAR in AMI is still justified from a technical point of view in the current era and whether superiority of TAR results is also evident in emergency patients with AMI undergoing CABG. METHODS: In this retrospective analysis of 434 consecutive patients undergoing CABG for AMI with either TAR or with a combination of one internal mammary artery and SV grafts between 2008 and 2014, procedural data, short-term and mid-term outcome were compared. Propensity score matching of the groups was performed. RESULTS: After propensity score matching, 250 patients were included in the analysis (TAR group: n = 98; SV group n = 152). The procedural time (TAR group: 211 min vs. SV group: 200 min, p = 0.46) did not differ between the groups. Erythrocyte transfusion rates were higher in the SV group (76% vs. 57%; p < 0.001). Rates of re-exploration for bleeding did not differ. Thirty-day mortality rates were comparable (TAR group: 3.4% vs. SV group: 4.5%, p = 0.68). Kaplan-Meier analysis until 7 years postoperatively revealed a tendency for improved survival after TAR (75% vs. 62%; log-rank p = 0.12). CONCLUSION: TAR neither impairs rapid revascularization nor reduces its safety in patients with AMI. It may result in improved long-term outcome and should be preferred in the clinical setting of AMI.

Is delayed surgical revascularization in acute myocardial infarction useful or dangerous? New insights into an old problem.

OBJECTIVES: Haemodynamically stable patients admitted for coronary artery bypass grafting in acute myocardial infarction often undergo delayed surgery in order to avoid the risks of emergency surgery. However, initially stable patients undergoing delayed surgery may develop low cardiac output syndrome (LCOS) during the waiting period, which might be a major drawback of this strategy. We aim to define risk factors and clinical consequences of LCOS during the waiting period. METHODS: A total of 530 consecutive patients with acute myocardial infarction (33% non-ST-segment elevation myocardial infarction and 67% ST-segment-elevation myocardial infarction) underwent isolated coronary artery bypass grafting between 2008 and 2013. Outcomes after either immediate (<48 h after onset of symptoms) or delayed (>48 h after onset of symptoms) therapy were compared. Predictors of preoperative development of LCOS were identified using multivariate regression analysis. RESULTS: Of the 327 patients undergoing delayed therapy, 39 (12%) developed preoperative LCOS, resulting in increased mortality compared with patients who remained stable (21 vs 7.6%, P < 0.001). Immediate therapy resulted in similar mortality compared with delayed therapy (6.4 vs 7.6%; P = 0.68) and better 7-year survival (70 vs 55%; P < 0.001). Predictors of developing LCOS were reduced left ventricular function (odds ratio 4.4), renal impairment (odds ratio 3.0), acute pulmonary infection (odds ratio 3.4) and the extent of troponin elevation at admission (odds ratio 1.01 per increase by 1 µg/l). CONCLUSIONS: In patients with acute myocardial infarction undergoing delayed coronary artery bypass grafting, preoperative LCOS is a relevant and dangerous condition that can be avoided by operating immediately or by carefully selecting patients to be delayed according to the risk parameters identified preoperatively.