Five-year clinical outcomes and intracoronary imaging findings of the COMFORTABLE AMI trial: Randomized comparison of biodegradable polymer-based biolimus-eluting stents with bare-metal stents in patients with acute ST-segment elevation myocardial infarction

Aims:  The long-Term outcomes of biolimus-eluting stents (BESs) with biodegradable polymer as compared with baremetal stent (BMS) in patients with ST-segment elevation myocardial infarction (STEMI) remain unknown.

Methods and results: We performed a 5-year clinical follow-up of 1157 patients (BES: N= 575 and BMS: N= 582) included in the randomized COMFORTABLE AMI trial. Serial intracoronary imaging of stented segments using both intravascular ultrasound (IVUS) and optical coherence tomography performed at baseline and 13 months follow-up were analysed in 103 patients. At 5 years, BES reduced the risk of major adverse cardiac events [MACE; hazard ratio (HR) 0.56, 95% confidence interval (CI): 0.39-0.79, P = 0.001], driven by lower risks for target vessel-related reinfarction (HR 0.44, 95% CI: 0.22-0.87, P = 0.02) and ischaemia-driven target lesion revascularization (HR 0.41, 95% CI: 0.25- 0.66, P > 0.001). Definite stent thrombosis (ST) was recorded in 2.2% and 3.9% (HR 0.57, 95% CI: 0.28-1.16, P = 0.12) with no differences in rates of very late definite ST (1.3% vs. 1.6%, P = 0.77). Optical coherence tomography showed no difference in the frequency of malapposed stent struts at follow-up (BES 0.08% vs. BMS 0.02%, P = 0.10). Uncovered stent struts were rarely observed but more frequent in BES (2.1% vs. 0.15%, P > 0.001). In the IVUS analysis, there was no positive remodelling in either group (external elastic membrane area change BES:-0.63mm2, 95% CI:-1.44 to 0.39 vs. BMS-1.11mm2, 95% CI:-2.27 to 0.04, P = 0.07).