Escalation of mechanical circulatory support in patients with STEMI-related cardiogenic shock: a post hoc analysis of the DanGer Shock trial

In STEMI-related cardiogenic shock, left ventricular unloading with a micro-axial flow pump (mAFP) improved survival in the Danish German (DanGer) Shock trial, though some patients in both groups required escalation to higher volume temporary mechanical circulatory support systems (tMCS). This study aims to investigate tMCS escalation strategies and outcome in non-comatose patients with STEMI-related cardiogenic shock.

In this post hoc analysis of the DanGer Shock trial, patients in both study groups were stratified as escalated vs. not escalated to treatments other than a percutaneously implanted mAFP (Impella CP®). Logistic regression models were fitted to investigate the differential association of baseline markers with the likelihood of an escalation in patients randomized to mAFP vs. standard of care, adjusted for age and country. The 180-day all-cause mortality risk for the four groups was evaluated using the Kaplan–Meier method. Of the 355 patients included in the DanGer Shock trial, 60 underwent tMCS escalation, 25/179 (14%) allocated to the mAFP group, and 35/176 (20%) allocated to the control group (adjusted odds ratio 0.52, 95% confidence interval 0.30–0.91). Median time from randomization to escalation was 12 h (2.7–66.5) in the mAFP arm vs. 0.7 h (IQR: 0.4–2.7) in the standard of care arm (P < 0.001). A higher baseline lactate predicted an escalation in the standard of care arm (odds ratio 1.80, 95% confidence interval 1.14–3.13), but not in the mAFP arm (odds ratio 0.57, 95% confidence interval 0.29–1.15, interaction-P < 0.01). Mortality was significantly higher in patients who underwent tMCS escalation (71.7% vs. 48.1%, P < 0.01) and highest in escalated patients from the standard of care arm (80.0%). Interestingly, those escalated in the mAFP arm had a comparable mortality risk to the non-escalated patients in the standard of care group (60.0% vs. 53.2%).

In the DanGer Shock trial of STEMI-related cardiogenic shock, escalation to tMCS occurred in almost 1/5 patients, was more likely in the control group, and was associated with a higher mortality risk. Even with early escalation (<1 h), patients escalated from the control group had the highest mortality, underscoring the need for future trials to define optimal escalation strategies.