Timing of IABP initiation and its impact on outcomes in acute myocardial infarction with cardiogenic shock: insights from a bi-center retrospective study

Clinical Research in Cardiology https://doi.org/10.1007/s00392-026-02951-1 ORIGINAL PAPER Timing of IABP initiation and its impact on outcomes in acute myocardial infarction with cardiogenic shock: insights from a bi‑center retrospective study Istvan Bojti1 · Sarolta Bojtine Kovacs2,3 · David Kovacs4 · Antonia Ziegler1 · Alexander Maier1 · Dirk Westermann1 · Miroslaw Ferenc1 · Attila Csaba Nagy5 · Kalman Racz6 · Zsolt Koszegi7 · Gabor Tamas Szabo7 Received: 15 December 2025 / Accepted: 21 May 2026 © The Author(s) 2026 Abstract Background The optimal timing of intra-aortic balloon pump (IABP) initiation in cardiogenic shock (CS) complicating acute myocardial infarction (AMI) remains uncertain. Contemporary ESC guidance and the recent EACTS/STS/AATS MCS guideline highlight gaps regarding timing, patient selection, and ischemic burden. In this study, the association between IABP timing, myocardial area at risk (AAR), and survival in AMI-CS was evaluated. Methods We retrospectively analyzed 399 AMI-CS patients treated with primary PCI at two tertiary centers. Patients were categorized as no IABP (n = 124), non-rescue IABP (started during PCI; n = 216), or rescue IABP (inserted after PCI; n = 59). Clinical and angiographic parameters, including AAR quantified by a coronary anatomy–based algorithm, were assessed. Multivariable logistic regression identified predictors of in-hospital and 1-year mortality. Results Non-rescue IABP was independently associated with lower in-hospital mortality vs. no IABP (OR 0.29, 95% CI 0.16–0.52). Rescue IABP showed a weaker association with lower in-hospital mortality (OR 0.41, 95% CI 0.19–0.89). At 1 year, mortality was higher in both no IABP (OR 3.27, 95% CI 1.86–5.76) and rescue IABP groups (OR 2.04, 95% CI 1.04–3.98) compared with nonrescue IABP. An augmented inverse-probability weighted (AIPW) analysis confirmed these findings, demonstrating a significant reduction in 1-year mortality with early IABP use compared with no IABP (ATE − 0.24, 95% CI − 0.375 to − 0.104), whereas no significant effect was observed for rescue IABP. A significant interaction between AAR and timing indicated that early IABP offered the greatest benefit in patients with moderate AAR (30–55%), whereas no benefit was observed with extensive AAR (> 80%). Conclusions In AMI-CS, early IABP initiation was associated with improved in-hospital and long-term survival, particularly in patients with a moderate AAR. These findings support the need for refining IABP use based on both ischemic burden and the timing of hemodynamic support. Trial registration number and date of registration. DRKS00038637, 03.12.2025. * Istvan Bojti 1 Department of Cardiology and Angiology, Faculty of Medicine, University Heart Center Freiburg, University of Freiburg, Freiburg, Germany 2 IMM‑PACT Cluster of Excellence, Faculty of Medicine, University of Freiburg, Freiburg, Germany 3 Section of Molecular Hematology, Department of Medicine I, Hematology, Oncology and Stem Cell Transplantation, Medical Center, Faculty of Medicine, University of Freiburg, University of Freiburg, Freiburg, Germany 4 Department of Otorhinolaryngology and Head‑Neck Surgery, Faculty of Medicine, University of Debrecen, Debrecen, Hungary 5 Department of Epidemiology, Faculty of Health Sciences, University of Debrecen, Debrecen, Hungary 6 Department of Forensic Medicine, Faculty of Medicine, University of Debrecen, Debrecen, Hungary 7 Department of Cardiology and Cardiac Surgery, Faculty of Medicine, University of Debrecen, Debrecen, Hungary Vol.:(0123456789) Clinical Research in Cardiology Graphical Abstract Keywords Acute myocardial infarction · Cardiogenic shock · IABP · Area at risk Introduction Cardiogenic shock (CS) represents a heterogeneous clinical syndrome arising from multiple etiologies—including acute myocardial infarction (AMI), acute decompensated heart failure, fulminant myocarditis, valvular disease, and profound post-cardiac surgery failure—and remains associated with mortality rates exceeding 40% despite significant advances in revascularization and intensive care [1]. Regardless of its underlying etiology, CS is characterized by rapidly progressive circulatory collapse and end-organ hypoperfusion, often emerging mechanical circulatory support (MCS) devices to stabilize hemodynamics and bridge patients to recovery or advanced therapies [2, 3]. MCS modalities provide varying levels of circulatory augmentation, the intra-aortic balloon pump (IABP) offers modest support (0.5–1.0 L/min), while the Impella system provides more substantial cardiac unloading (2.5–4.0 L/min) [4], and veno-arterial extracorporeal membrane oxygenation (VA-ECMO) delivers full cardiopulmonary support but requires extensive expertise and resources [5]. Observational data suggest that early MCS initiation—particularly before irreversible end-organ damage—may improve survival across CS etiologies [6, 7]. The recently published EACTS/STS/AATS guideline on temporary mechanical circulatory support, focusing on short-term MCS use in adult cardiac surgery and perioperative cardiogenic shock, highlights persistent gaps in the evidence base for AMI-related CS (AMI-CS). Specifically, the guideline emphasizes that the most relevant randomized trial—IABP-SHOCK II—demonstrated no mortality benefit with routine IABP use in AMI-CS, yet did not evaluate the timing of IABP initiation or stratify key subgroups, including patients with varying degrees of threatened myocardium [8, 9]. Similar concerns were raised by Szabó et al. regarding the BCIS-1 study evaluating IABP use in high-risk PCI, in which neither the extent of jeopardized myocardium nor the precise timing of counterpulsation initiation were prospectively stratified, potentially contributing to the trial’s neutral results [10, 11]. These limitations reinforce key unanswered questions, particularly which CS patients and at what stage of ischemic injury may benefit most from IABP support? Notably, the concept of a jeopardized myocardial territory—commonly expressed as the area at risk (AAR)—is Clinical Research in Cardiology relevant not only in AMI-CS but across multiple CS contexts. In AMI-CS, the AAR represents acutely ischemic but potentially salvageable myocardium whose reperfusion and unloading can prevent infarct expansion, left ventricular dysfunction, and refractory shock [12]. Even in selected forms of non-ischemic CS, such as acute myocarditis or decompensated heart failure, the amount of salvageable myocardial tissue—or the degree of metabolic and microvascular reserve—may influence the effectiveness of early support [13]. Thus, across etiologies, the presence and extent of jeopardized but viable myocardium may determine both the biological plausibility and potential impact of MCS therapies. Despite its modest hemodynamic augmentation, IABP remains the most accessible and affordable temporary MCS modality worldwide. Its relatively low cost renders it esp (...truncated)