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

The Society for Cardiovascular Angiography and Intervention (SCAI) has suggested an arrest modifier for patients with anoxic brain injury at each cardiogenic shock (CS) stage. However, outcomes differ between those with favorable and unfavorable 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.

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, favorable and unfavorable AMICS-OHCA patients; and (2) to evaluate the impact of intubation on 30-day mortality across all 3 above-mentioned categories of patients with AMICS .

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, favorable AMICS-OHCA (witnessed arrest and return of spontaneous circulation <30 minutes), and unfavorable AMICS-OHCA. Multivariable Cox regression was used to compare 30-day mortality rates among the 3 groups, and subsequent subgroup analyses assessed the association between intubation and 30-day mortality in each group.

In total, 2226 patients were included (AMICS without OHCA = 1313, favorable AMICS-OHCA = 490, and unfavorable AMICS-OHCA = 423). Favorable AMICS-OHCA was associated with a lower (HR 0.74, 95% CI 0.59-0.92), but unfavorable AMICS-OHCA with a higher adjusted risk of 30-day mortality (HR 1.31, 95% CI 1.06-1.63) compared to patients with AMICS without OHCA. Intubation was associated with a higher 30-day mortality rate across all groups.

In AMICS patients undergoing percutaneous coronary intervention, 30-day mortality risk was lower in patients with favorable OHCA compared to those with unfavorable OHCA. Intubation was an independent predictor of 30-day mortality in all subgroups. These findings highlight the need for better characterization of OHCA rather than using 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.