Objectives: Prophylactic intra-aortic balloon pump (IABP) insertion is recommended for high-risk patients undergoing coronary artery bypass grafting surgery (CABG). Criteria for high-risk patients benefiting from IABP are unclear. IABP effects on coronary perfusion and afterload might be particularly relevant in patients with critically reduced coronary perfusion and acutely impaired left-ventricular ejection fraction (LVEF), namely patients with acute myocardial infarction (AMI). We analyzed the outcomes of AMI patients undergoing CABG with or without prophylactic IABP.
Methods: 484 AMI patients (NSTEMI or STEMI < 5 days before surgery) without cardiogenic shock underwent isolated CABG between 2008 and 2013. In 178, an IABP was inserted preoperatively. After propensity-score matching, perioperative outcomes of 400 patients were analyzed (IABP: 150; control: 250). Cardiac injury was quantified as serum levels of cardiac biomarkers until postoperative day 4 adjusted for the preoperative baseline (BL) values.
Results: Baseline and operative characteristics were balanced between the groups except for a higher rate of patients with LVEF< 30% in the IABP group (26% versus Control: 12.6%; p = 0.032). EuroSCORE II in the IABP group (7.2%) and control group (6.7%) were comparable (p = 0.67). 7.2% of control patients received an IABP intra- or postoperatively. Postoperative ECLS was only needed in the control group (1.2% versus 0%; p = 0.01). Acute kidney injury (AKIN stages 2 and 3) tended to occur more often in the control group (10% versus 6.8%; p = 0.27). Postoperative mean troponin I (IABP: 8.2*BL versus control: 32*BL; p = 0.035), CK-MB (1.5*BL versus 2.1*BL; p = 0.045) and CK (4.3*BL versus 7.8*BL; p = 0.001) levels were reduced in the IABP group compared with the control group. In-hospital mortality in the IABP group was 46% of the mortality predicted by EuroSCORE II, compared with 95% in the control group. Between the groups, mortality was non-significantly reduced in the IABP group (3.3% versus control: 6.4%; p = 0.18). Mortality (IABP versus control) was more affected in patients with preoperative LVEF≤30% (HR 0.25; 95%-CI 0.046–1.3; p = 0.13) compared with LVEF>30% (HR 0.56; 95%-CI 0.15–2.1; p = 0.55).
Conclusion: Prophylactic IABP in CABG for AMI reduces perioperative cardiac injury. It is associated with reduced mortality compared with preoperative risk estimation and might reduce mortality compared with withhold of preoperative IABP, especially in patients with severely reduced LVEF.
