Comparative Analysis of Patient Characteristics in Cardiogenic Shock Studies: Differences Between Trials and Registries

Objectives: This study sought to evaluate the differences in cardiogenic shock patient characteristics in trial patients and real-life patients. Background: Cardiogenic shock (CS) is a leading cause of mortality in patients presenting with acute myocardial infarction (AMI). However, the enrollment of patients into clinical trials is challenging and may not be representative of real-world patients. Methods: We performed a systematic review of studies in patients presenting with AMI-related CS and compared patient characteristics of those enrolled into randomized controlled trials (RCTs) with those in registries. Results: We included 14 RCTs (n = 2,154) and 12 registries (n = 133,617). RCTs included more men (73% vs 67.7%, P < 0.001) compared with registries. Patients enrolled in RCTs had fewer comorbidities, including less hypertension (61.6% vs 65.9%, P < 0.001), dyslipidemia (36.4% vs 53.6%, P < 0.001), a history of stroke or transient ischemic attack (7.1% vs 10.7%, P < 0.001), and prior coronary artery bypass graft surgery (5.4% vs 7.5%, P < 0.001). Patients enrolled in RCTs also had lower lactate levels (4.7 ± 2.3 mmol/L vs 5.9 ± 1.9 mmol/L, P < 0.001) and higher mean arterial pressure (73.0 ± 8.8 mm Hg vs 62.5 ± 12.2 mm Hg, P < 0.001). Percutaneous coronary intervention (97.5% vs 58.4%, P < 0.001) and extracorporeal membrane oxygenation (11.6% vs 3.4%, P < 0.001) were used more often in RCTs. The in-hospital mortality (23.9% vs 38.4%, P < 0.001) and 30-day mortality (39.9% vs 45.9%, P < 0.001) were lower in RCT patients. Conclusions: RCTs in AMI-related CS tend to enroll fewer women and lower-risk patients compared with registries. Patients enrolled in RCTs are more likely to receive aggressive treatment with percutaneous coronary intervention and extracorporeal membrane oxygenation and have lower in-hospital and 30-day mortality.