External validity of a contemporaneous primary percutaneous coronary intervention trial in patients with acute ST-elevation myocardial infarction: insights from a single-centre investigation

EuroIntervention. 2016 Oct 20;12(9):1135-1143. doi: 10.4244/EIJV12I9A185.


Aims: Randomised controlled trials (RCTs) represent the most robust source of evidence-based medicine. However, the generalisability of RCTs is limited by the inclusion of selected populations. We sought to assess the external validity of a contemporary trial including patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI).

Methods and results: Patients presenting to Bern University Hospital during the inclusion period of the COMFORTABLE AMI trial were divided into three groups: RCT participants (41%), eligible not included (17.5%), and excluded patients (41.5%). Major adverse cardiac events (MACE) were defined as one-year death and myocardial infarction. RCT participants compared with RCT-eligible patients had comparable baseline characteristics and outcomes; however, excluded patients differed in risk and had higher rates of MACE (HR 3.63, 95% CI: 2.03-6.48, p<0.001), death (HR 6.23, 95% CI: 2.93-13.24, p<0,001) and definite/probable stent thrombosis (HR 3.63, 95% CI: 1.79-7.36, p<0.001). Inability to provide consent was the most frequent exclusion criterion and was independently associated with an increased risk for MACE (HR 6.85, 95% CI: 3.97-11.81, p<0.001).

Conclusions: In this single-centre investigation, results from the COMFORTABLE AMI trial appeared applicable to a broad representation of RCT-eligible patients. However, patients excluded from the trial represented a higher-risk population with impaired clinical outcomes and a lower adherence to cardiovascular medication.

MeSH terms

  • Aged
  • Aged, 80 and over
  • Cause of Death
  • Comorbidity
  • Eligibility Determination
  • Female
  • Humans
  • Hydroxymethylglutaryl-CoA Reductase Inhibitors / therapeutic use*
  • Logistic Models
  • Male
  • Middle Aged
  • Mortality
  • Myocardial Infarction / epidemiology
  • Percutaneous Coronary Intervention / methods*
  • Platelet Aggregation Inhibitors / therapeutic use*
  • Postoperative Care
  • Proportional Hazards Models
  • Randomized Controlled Trials as Topic
  • Recurrence
  • Renal Insufficiency / epidemiology
  • Reproducibility of Results
  • ST Elevation Myocardial Infarction / epidemiology
  • ST Elevation Myocardial Infarction / therapy*
  • Secondary Prevention
  • Treatment Outcome


  • Hydroxymethylglutaryl-CoA Reductase Inhibitors
  • Platelet Aggregation Inhibitors