Abstract
Background: Cardiogenic shock complicating acute myocardial infarction (AMICS) remains a high 30-day mortality. Mechanical circulatory support devices are increasingly used in AMICS, but their effects on mortality vary partly because of shock severity. Aims: This study aimed to evaluate the association between intra-aortic balloon pump (IABP) and 30-day mortality in patients with early-stage AMICS. Methods: We retrospectively analyzed patients with ST-segment elevation myocardial infarction (STEMI) based on a multicenter clinical trial (NCT04996901). Patients were stratified by IABP use, and shock severity was classified according to the Society for Cardiovascular Angiography and Interventions (SCAI) SHOCK stages. The primary outcome was 30-day all-cause mortality. The association between IABP and 30-day mortality was evaluated across shock stages using propensity score matching, weighting, and logistic regression. Results: Five thousand three hundred forty-three patients were included, and 299 received IABP. The SCAI SHOCK stage was associated with 30-day mortality (odds ratio [OR], 20.19; 95% confidence interval [CI], 13.60-29.97; P < 0.001). In the 580 matched patients, a significant interaction between IABP and 30-day mortality at different shock stages was observed ( P = 0.005). Intra-aortic balloon pump was associated with lower 30-day mortality among patients with shock stage A/B (5.8% vs. 1.2%; OR, 0.19; 95% CI, 0.03-0.73; P = 0.034) but not stage C/D/E (29.3% vs. 38.1%; OR, 1.49; 95% CI, 0.84-2.65; P = 0.172). These results were confirmed by sensitivity analyses of the weighted cohort. Conclusions: Intra-aortic balloon pump reduced 30-day mortality in patients with early-stage AMICS. The SCAI SHOCK stage provides risk stratification for patients with STEMI and helps identify those who may respond well to IABP.