Randomized clinical trials of patients with acute myocardial infarction-related cardiogenic shock: a systematic review of used cardiogenic shock definitions and outcomes

Background: Cardiogenic shock (CS) is a critical complication to acute myocardial infarction (AMI), with short-term mortality rates exceeding 40%. However, no international consensus of a CS definition exists. This may compromise interstudy comparability. Aims: The aim of the current study was to review differences and similarities of CS enrolment criteria in AMI-related CS randomized clinical trials (RCT). Methods: From the electronic databases MEDLINE and EMBASE we identified all AMI-related CS trials. Results: A total of 19 trials comprising a total of 2674 unique patients with CS were identified. Seven trials investigated left ventricular assist devices, eight investigated medical treatments, three percutaneous coronary intervention (PCI), and one trial investigated targeted temperature management. The inclusion criteria, baseline hemodynamics, endpoints, and mortality varied markedly between trials. Hypotension was the most frequent overall inclusion criterion (17 [90%] trials), and a systolic blood pressure <90 mm Hg (and/or need of vasopressors) was the most frequently used limit. Twelve (63%) trials had signs of impaired end-organ perfusion as an inclusion criterion and 10 (53%) signs of impaired cardiovascular function most frequently low cardiac index and reduced left ventricular ejection fraction. Ten (53%) trials included patients resuscitated from a cardiac arrest, three trials excluded cardiac arrest patients whereas six trials did not state whether cardiac arrest was an exclusion criterion. Mortality ranged from 8% to 73%. Conclusions: The RCTs of AMI-related CS have marked heterogeneity in enrolment criteria and outcomes potentially hampering interstudy comparability. The overall consensus of CS enrolment criteria appears needed for future selection of patients.