Preoperative intra-aortic balloon pump improves the clinical outcomes of off-pump coronary artery bypass grafting in left ventricular dysfunction patients

Abstract

Severe left ventricular (LV) dysfunction patients undergoing off-pump coronary artery bypass grafting (OPCAB) are often associated with a higher mortality. The efficacy and safety of the preoperative prophylactic intra-aortic balloon pump (IABP) insertion is not well established. 416 consecutive patients with severe LV dysfunction (ejection fraction ≤35%) undergoing isolated OPCAB were enrolled in a retrospective observational study. 191 patients was enrolled in the IABP group; the remaining 225 patients was in control group. A total of 129 pairs of patients were propensity-score matched. No significant differences in demographic and preoperative risk factors were found between the two groups. The postoperative 30-day mortality occurred more frequently in the control group compared with the IABP group (8.5% vs. 1.6%, p = 0.02). There was a significant reduction of low cardiac output syndrome in the IABP group compared with the control group (14% vs. 6.2%, p = 0.04). Prolonged mechanical ventilation (≥48 h) occurred more frequently in the control group (34.9% vs. 20.9%, p = 0.02). IABP also decreased the postoperative length of stay. Preoperative IABP was associated with a lower 30-day mortality, suggesting that it is effective in patients with severe LV dysfunction undergoing OPCAB.

Figure 1. Study flow.

A total of 18,719 patients undergoing isolated OPCAB were screened. The LVEF of 446 patients was less than 35%, and 416 patients were enrolled. Prophylactic IABP was inserted in 191 patients (IABP group); 225 patients did not receive prophylactic IABP (control group); 258 patients (129 patients in each group) were propensity matched. The postoperative 30-day mortality and morbidity were compared. IABP denotes intra-aortic balloon pump, LVEF denotes left ventricular ejection fraction, and OPCAB denotes off-pump coronary artery bypass graft.

Figure 2. Love (left panel) and Jitter plot (right panel) in propensity-matched analysis.

Figure 3. Kaplan-Meier cumulative 30-day mortality after surgery.

Kaplan-Meier survival curves shows 30-day mortality in surgical patients with preoperative IABP (red line) and without preoperative IABP (control, blue line) before (A) and after (B) propensity-score matching. IABP denotes intra-aortic balloon pump.

Figure 4. Subgroup analysis for 30-day mortality after surgery.

Subgroup analyses are shown for 30-day mortality between patients with preoperative IABP vs. controls. The p-value for interaction represents the likelihood of interaction between the variable and the relative treatment effect. BMI denotes body mass index, LV denotes left ventricular, NYHA denotes New York Heart Association, and EuroSCORE denotes European System for Cardiac Operative Risk Evaluation.