# Heterogeneity of Treatment Effect for Intra‐Aortic Balloon Pump Use Across Lactate Trajectories in Cardiogenic Shock Patients Supported by VA‐ECMO: An Analysis of the Chinese Extracorporeal Life Support Registry

## TL;DR

This study shows that lactate levels over time can predict outcomes in heart attack patients on VA-ECMO and that IABP treatment has different effects depending on these patterns.

## Contribution

The study identifies distinct lactate trajectories and demonstrates how they influence treatment outcomes for IABP in cardiogenic shock patients.

## Key findings

- Three distinct lactate trajectories were identified in patients with cardiogenic shock.
- Higher mortality was observed in Classes 2 and 3 compared to Class 1.
- IABP use increased mortality and complications in Class 1 but not in Classes 2 or 3.

## Abstract

This study aimed to investigate the heterogeneity of treatment effect for intra‐aortic balloon pump (IABP) across various lactate trajectories in patients with acute myocardial infarction‐related cardiogenic shock (AMICS) supported by veno‐arterial extracorporeal membrane oxygenation (VA‐ECMO). Retrospective data from the China Extracorporeal Life Support Registry included AMICS patients who received VA‐ECMO. The latent class growth model was used to identify distinct lactate trajectories. The primary outcome was in‐hospital mortality. Baseline characteristics and outcomes were compared across trajectory classes, and the heterogeneity of treatment effect for IABP was assessed. Among 1264 patients, three lactate trajectories were identified. Compared with Class 1, both Class 2 (odds ratio [OR] 2.03, 95% confidence interval [CI] 1.54–2.67) and Class 3 (OR 3.99, 95% CI 2.77–5.78) had significantly higher in‐hospital mortality. Moreover, heterogeneity of treatment effect across the classes was found. IABP use was associated with increased risks of in‐hospital mortality and multiple complications (bleeding, renal, metabolic, and infection) in Class 1, whereas no associations were observed in Class 2 or Class 3, except for a higher risk of infection in Class 2. In summary, lactate trajectories can stratify mortality risk in AMICS patients receiving VA‐ECMO support and reflect heterogeneous responses to IABP treatment.

Lactate trajectories can stratify the mortality risk in patients with acute myocardial infarction‐related cardiogenic shock receiving VA‐ECMO and reflect heterogeneity of treatment effect for intra‐aortic balloon pump.