Impact of participation in randomized trials of reperfusion therapy on the time to reperfusion and hospital mortality in ST-segment elevation myocardial infarction: A single-centre cohort study

Aim: There is uncertainty as to whether consenting and randomizing patients in randomized clinical trials (RCTs) in acute ST-segment elevation myocardial infarction (STEMI) delays reperfusion and increases mortality. The aim of this study was to determine whether participation of patients with STEMI in RCTs is associated with delay in implementation of reperfusion therapy and increased hospital mortality.

Methods and results: A consecutive sample of 2523 patients, admitted within 6 hours of symptom onset without cardiogenic shock, was recruited from a single tertiary academic centre. They were categorized according to participation (n=392, 15.5%) or nonparticipation (n=2131, 84.5%) in RCTs of reperfusion therapy. Primary outcome was hospital mortality. Additional outcome was time from symptom onset to receipt of reperfusion therapy. Trial participants were more likely to receive fibrinolysis with a 37 min delay in comparison with patients not included in RCTs. Time from symptom onset to reperfusion (minutes) was longer for trial participants than nonparticipants (246 ± 85 vs 233 ± 93, p=0.01). Hospital mortality was 3.61% for nonparticipants. Expected mortality (based on risk modeling) for trial participants was 2.74% (p=0.014 vs nonparticipants). Observed mortality was 1.53% (p=0.034 vs nonparticipants; p=0.16 vs expected mortality). In a multivariable analysis using logistic regression, participation in a RCT was not an independent correlate of hospital mortality (odds ratio 0.54, 95% confidence interval 0.23-2.43, p=0.16).

Conclusions: In this consecutive cohort, despite a longer delay to reperfusion, there was no indication that participation in a RCT, starting before initiation of reperfusion therapy, was associated with a detectable increase in risk of hospital mortality among patients with STEMI. These data suggest that it is possible to consent and randomize patients with STEMI into RCTs without jeopardizing their survival.