Impact of Cardiac Arrest in Patients with Cardiogenic Shock due to ST-Elevation Myocardial Infarction

Background: Cardiogenic shock (CS) frequently complicates ST-elevation myocardial infarction (STEMI) and may be associated with cardiac arrest occurring either as out-of-hospital (OHCA) or in-hospital cardiac arrest (IHCA). Aim: To compare clinical characteristics, coronary anatomy, management and survival among patients with CS without cardiac arrest (STEMI-CS-no CA), CS with OHCA (STEMI-CS-OHCA) and CS with IHCA (STEMI-CS-IHCA). Methods: We conducted a retrospective study including consecutive patients with CS and STEMI undergoing immediate coronary angiography and percutaneous coronary intervention (PCI) who were admitted to two tertiary university hospitals between 2016 and 2025. Results: Among 345 patients, 150 (43.5%) had STEMI-CS-no CA, 120 (34.8%) STEMI-CS-OHCA, and 75 (21.7%) STEMI-CS-IHCA. STEMI-CS-IHCA patients were older, less frequently presented with an initial shockable rhythm (36.0% vs 61.0%, p=0.002) and had shorter time to return of spontaneous circulation (10.0 vs 19.6 minutes, p<0.001) compared to STEMI-CS-OHCA. They had also lower arterial pressure, left ventricular ejection fraction, estimated glomerular filtration rate and higher arterial lactate compared to STEMI-CS-no CA and STEMI-CS-OHCA. Coronary complexity increased progressively with SYNTAX score rising from 18.6 in STEMI-CS-no CA to 21.5 in STEMI-CS-OHCA and to 27.2 in STEMI-CS-IHCA (p<0.001). At 1-year, all-cause mortality was 67.3% in STEMI-CS-no CA, 78.3% in STEMI-CS-OHCA (p=0.004) and 82.7% in STEMI-CS-IHCA (p<0.001) without significant difference between cardiac arrest subgroups (p=0.555). Conclusion: In STEMI-related CS, concomitant OHCA or IHCA is associated with distinct clinical profiles, coronary anatomy, intensity of treatment and markedly impaired long-term survival.