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

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 non-rescue 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.