Impact of preoperative intra-aortic balloon pump on outcomes in coronary artery bypass grafting for unprotected left-main coronary artery disease

Background: Preoperative intra-aortic balloon pump (IABP) before coronary artery bypass grafting (CABG) could improve operative outcomes by augmenting the diastolic coronary blood flow. Data on preoperative IABP use in patients with left-main coronary artery (LMCA) disease are limited. This study aimed to characterize patients who received preoperative IABP before CABG for LMCA and evaluate its effect on postoperative outcomes. Methods: This multicenter retrospective cohort study that included consecutive 914 patients who underwent CABG for unprotected LMCA disease from January 2015 to December 2019 in 14 tertiary referral centers. Patients were grouped according to the preoperative IABP insertion into patients with IABP (n=101) and without IABP (n=813). Propensity score matching adjusting for preoperative variables, with 1:1 match and a caliber of 0.03 identified 80 matched pairs. The primary outcomes used in propensity score matching were cardiac mortality and major adverse cardiac and cerebrovascular events (MACCE). Results: IABP was commonly inserted in patients with previous myocardial infarction (MI), chronic kidney disease, peripheral arterial disease, and congestive heart failure. IABP patients had higher EuroSCORE [ES >8%: 95 (11.86%) vs. 40 (39.60%), P<0.001] and SYNTAX {29 [interquartile range (IQR) 25-35] vs. 33 (IQR 26-36); P=0.02} scores. Preoperative cardiogenic shock and arrhythmia were more prevalent in patients with IABP, while acute coronary syndrome was more prevalent in patients without IABP. After matching, there was no difference in vasoactive inotropic score between groups [3.5 (IQR 1-7.5) vs. 6 (IQR 1-13.5), P=0.06], and lactate levels were nonsignificantly higher in patients with IABP [2.4 (IQR 1.4-4.5) vs. 3.1 (IQR 1.05- 7.75), P=0.05]. There were no differences between groups in acute kidney injury [20 (25%) vs. 26 (32.5%), P=0.34], cerebrovascular accidents [3 (3.75%) vs. 4 (5%), P>0.99], heart failure [5 (6.25%) vs. 7 (8.75%), P=0.75], MI [7 (8.75%) vs. 8 (10%), P>0.99], major adverse cardiac and cerebrovascular events [10 (12.5%) vs. 17 (21.25%), P=0.21], and cardiac mortality [6 (7.50%) vs. 14 (17.50%), P=0.09]. Patients who received IABP had longer ventilation times [8.5 (IQR 6-23) vs. 15.5 (IQR 5-50.5) h, P=0.03] and intensive care unit (ICU) stays [3 (IQR 2-5) vs. 4 (IQR 2-7.5) days, P=0.01]. Conclusions: Preoperative IABP in patients with LMCA might not be associated with reduced cardiac mortality or hospital complications. IABP could increase the duration of mechanical ventilation and ICU stay, and its use should be individualized for each patient.