Infarct-related cardiogenic shock with and without cardiac arrest: Insights from randomized trials of mechanical circulatory support

The Danish-German Cardiogenic Shock (DanGer-Shock) trial found a 180-day survival benefit with routine mechanical circulatory support (MCS) but notably excluded comatose pre-randomization cardiac arrest patients. Following the publication of DanGer Shock, the high six-month mortality rate of 58.5% among controls has come under scrutiny, as other studies have not reported similar rates. However, cardiac arrest cases are frequent in most MCS studies besides DanGer shock, which makes direct comparison across studies difficult.

To assess the 180-day mortality of patients assigned to the control group without cardiac arrest before randomization in available randomized MCS trials.

Individual patient data meta-analysis of MCS trials with six-month mortality data comparing routine MCS versus control in infarct-related cardiogenic shock. For this analysis, only patients randomized to the control group were assessed. The cohort was stratified based on whether they had received cardiopulmonary resuscitation before randomization and compared between patients in the DanGer and patients from other MCS trials. All-cause mortality at 180 days was assessed as a time-to-event by Cox regression, including an adjusted analysis.

Among 530 patients randomized to standard-of-care, 254 had not been resuscitated within 24 hours prior to randomization. 143 of these originated from the DanGer-Shock and 111 from seven other MCS trials. The control patients without cardiac arrest in the DanGer-shock had lower systolic blood pressure (median 80, (interquartile range (IQR) 70-91 mmHg) vs. 87 (73-107), p=0.005); lower left ventricular ejection fraction (20 % (IQR 15-30) vs. 27 % (IQR 20-35), p=0.003); but lower lactate (4.4 mmol/L (IQR 3.1-6.3) vs. 5.3 mmol/L (IQR 3.6-9.6), p=0.003). Mortality at day 180 in the DanGer-Shock non-arrested population was 60% and 59% in the other MCS trials (hazard ratio (HR) 1.10 (95% CI: 0.79-1.51) and adjusted HR 1.09 (95% CI: 0.74-1.58). In the control population with cardiac arrest (n=261), we found that the mortality at day 180 in DanGer-Shock cardiac arrest population was 52% (17/33) vs. 53% (121/229) in the other trials (hazard ratio (HR) 0.89 (95% CI: 0.53-1.47) and adjusted HR 0.71 (95% CI: 0.40-1.3).