Systolic blood pressure predicts survival benefit of microaxial flow pump in infarct related cardiogenic shock: A DanGer Shock analysis

Background Cardiogenic shock remains a severe complication of acute myocardial infarction (AMI-CS), with short-term mortality of 40–50%. Hypotension is a central diagnostic criterion as well as treatment target. The Danish-German (DanGer) Shock trial demonstrated a significant survival benefit from routine use of microaxial flow pump (mAFP) in selected AMI-CS patients. The DanGer Shock trial, along a recently published meta-analysis compiling data from nine individual trials in the field, showed a potential interaction with blood pressure at randomization, warranting further investigation. Purpose Investigate the influence of randomization systolic blood pressure on the treatment effect of mAFP in AMI-CS. Methods Post-hoc analysis of the DanGer Shock trial, which is an international multicenter, open-label clinical trial, randomizing AMI-CS patients to mAFP plus standard care or standard care alone. Inclusion criteria comprised adults with STEMI and cardiogenic shock (systolic blood pressure below 100mmHg or need for vasopressors, lactate > 2.5mmol/L, and left ventricular ejection fraction (LVEF) <45%). Main exclusion criteria were resuscitated out-of-hospital cardiac arrest with persistent Glasgow coma scale <8, mechanical complications, and right ventricular failure. Study endpoints are 180-day all-cause mortality. Statistical methods include cubic spline modeling, Kaplan Meier analysis, log-rank test, and multivariable logistic regression. Results Of the 355 DanGer Shock patients, 351 (98.9%) had available systolic blood pressure at randomization. 4 patients (1.1%) were included based on vasopressor need. The median age was 69 years (IQR:59-76), 74 (21%) females, the median left ventricular ejection fraction (LVEF) was 25% (IQR:15-30), and the median systolic blood pressure at randomization was 82mmHg (IQR:72-91). Patients with an initial systolic blood pressure below the median 82mmHg showed a significant 180-day all-cause mortality reduction when treated with mAFP compared to standard care (OR=0.34 (95%CI: 0.18-0.63), p<0.001). This survival benefit was not evident for systolic blood pressures above the median (OR:=0.96 95%CI: 0.53-1.7), p=0.90), (p for interaction=0.017). When assessing systolic blood pressure as a continuous variable, the same outcome was observed: As seen in Figure 1, patients with a systolic blood pressure below 83mmHg experienced a significant mortality risk reduction when treated with mAFP compared to standard care (p for interaction = 0.021 ). Survival in quartiles of randomization blood pressure is shown in Figure 2. Conclusion This exploratory post-hoc analysis suggests an impact of initial hemodynamic status on the survival benefit of mAFP in AMI-CS. In patients presenting an initial systolic blood pressure below 83 mmHg, treatment with a mAFP was associated with a significantly reduced risk of death. This survival benefit was not evident in patients with initial systolic blood pressures above 83 mmHg.