Timing of intra-aortic balloon pump support and early mortality after isolated coronary artery bypass grafting in patients with preserved ejection fraction: a single-centre retrospective cohort study

Abstract Background. An intra-aortic balloon pump (IABP) is sometimes needed after coronary artery bypass grafting (CABG), but it is unclear what the timing of that need says about the patient with preserved left ventricular function. Most published series mix different open-heart operations, and the chance of needing support depends partly on the operation. We studied IABP use and timing in one homogeneous group, comparing support already running when the patient left the operating room with rescue support started in the intensive care unit (ICU). Methods. We reviewed consecutive adults who had elective or urgent isolated on-pump CABG with cross-clamping between July 2024 and December 2025, all with a preoperative ejection fraction (EF) of at least 50%. The primary outcome was operative mortality: death during the index stay, or within 30 days. Patients given an IABP were grouped by when it went in and by where support was running: OR-IABP if the balloon was working as the patient came off bypass, ICU-IABP if it started later in the ICU. Results. Of 1224 patients, 57 (4.7%) received an IABP. Operative mortality was 49.1% with IABP and 2.3% without (p < 0.001), and rose across the preoperative, intraoperative and postoperative groups (18.8%, 38.5% and 71.4%; p = 0.002). It was 32.0% for OR-IABP (n = 25) and 71.4% for ICU-IABP (n = 28; p = 0.004); 30-day mortality was 24.0% and 67.9% (p = 0.001). Urgent surgery was more common in the OR-IABP group (76.0% versus 50.0%; p = 0.051). Crude odds of death were higher with ICU-IABP (odds ratio 5.31, 95% CI 1.64–17.19; p = 0.005); after adjustment for age, sex, renal function and urgency the estimate was 4.54 (0.84–24.46; p = 0.078). Conclusions. Needing an IABP after elective or urgent isolated CABG with preserved EF marks a very high early risk. Rescue support started in the ICU carried much higher crude mortality than support established before the patient left the operating room, even though the former group was less acutely ill. These findings raise a hypothesis; they do not show that earlier support saves lives.