Study Population

Using the data from January 2019 to December 2021, we included patients undergoing PCI from 1190 hospitals (n=734 379) (Figure 1). We excluded the patients with missing information on outcomes (n=50) and those outside the age range of 20 to 100 years (n=106). We also excluded patients who underwent PCI with a clinical presentation other than ACS (n=45 904), in an elective setting (n=78 280), and without CS (n=178 523). Of 24 516 patients undergoing PCI for ACS complicated with CS from 1072 hospitals, we also excluded patients who underwent PCI without MCS (n=12 101) and those with MCS other than an IABP/venoarterial extracorporeal membrane oxygenation (VA‐ECMO)/Impella (n=244). We ultimately identified 12 171 patients undergoing PCI for ACS complicated CS under MCS from 937 hospitals.

ACS indicates acute coronary syndrome; CS, cardiogenic shock; IABP, intra‐aortic balloon pump; MCS, mechanical circulatory support; PCI, percutaneous coronary intervention; and VA‐ECMO, venoarterial extracorporeal membrane oxygenation.

The eligible patients were stratified into 3 groups according to the MCS modalities: (1) IABP alone, (2) Impella, and (3) VA‐ECMO. The VA‐ECMO group was further stratified into 3 groups according to the concomitant MCS devices: (3a) VA‐ECMO alone, (3b) VA‐ECMO + IABP, and (3c) VA‐ECMO + Impella (ECPella). Given that the presence of patients receiving these modalities overlapped (Table S1), we categorized the groups according to the following hierarchy: VA‐ECMO outweighs Impella, and Impella outweighs IABP. ¹⁹