Intubation Rather Than Cardiac Arrest as a Risk-modifier of Mortality in Infarction-Related Cardiogenic Shock

BACKGROUND: The Society for Cardiovascular Angiography and Intervention (SCAI) has suggested an arrest modifier for patients with anoxic brain injury to each cardiogenic shock (CS) stage. However, outcomes differ between those with favourable and unfavourable out-of-hospital cardiac arrest (OHCA) characteristics. Intubation might capture a wider spectrum of critical illness and may alternatively predict mortality in patients with acute myocardial infarction-related CS (AMICS), with and without OHCA. OBJECTIVES: We aimed (1) To assess whether using 'arrest' as a modifier in the SCAI classification is justified, by comparing 30-day mortality risk in AMICS patients without OHCA, favourable and unfavourable AMICS-OHCA patients, and- 2) To evaluate the impact of intubation on 30-day mortality across all 3 abovementioned categories of AMICS patients. METHODS: We used data from the Netherlands Heart Registration (2017-2021) from 14 hospitals, including patients with AMICS undergoing percutaneous coronary intervention. Patients were stratified into 3 subgroups; AMICS without OHCA, favourable AMICS-OHCA (witnessed arrest and Return of Spontaneous Circulation <30 minutes) and unfavourable AMICS-OHCA. Multivariable Cox regression was used to compare 30-day mortality between the three groups and subsequent subgroup analyses assessed the association between intubation and 30-day mortality in each group. RESULTS: In total 2226 patients were included (AMICS without OHCA = 1313, favourable AMICS-OHCA = 490 and unfavourable AMICS-OHCA = 423). Favourable AMICS-OHCA was associated with lower (HR 0.74, 95%-CI 0.59- 0.92), but unfavourable AMICS-OHCA with higher adjusted risk of 30-day mortality (HR 1.31, 95%-CI 1.06- 1.63) compared to AMICS without OHCA. Intubation was associated with higher 30-day mortality across all groups. CONCLUSION: In AMICS patients undergoing PCI, 30-day mortality risk was lower in patients with favourable OHCA compared to those with unfavourable OHCA. Intubation was an independent predictor for 30-day mortality in all subgroups. These findings highlight the need for better characterization of OHCA rather than to use it as a binary risk modifier. Meanwhile, these results support further research to determine whether intubation is a robust clinical marker suitable for inclusion in the SCAI shock classification.