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 bare-metal 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 13months follow-up were analysed in 103 patients. At 5years, 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: -0.63mm(2), 95% CI: -1.44 to 0.39 vs. BMS -1.11mm(2), 95% CI: -2.27 to 0.04, P=0.07). Conclusion Compared with BMS, the implantation of biodegradable polymer-coated BES resulted in a lower 5-year rate of MACE in patients with STEMI undergoing primary percutaneous coronary intervention. At 13months, vascular healing in treated culprit lesions was almost complete irrespective of stent type. Clinical Trial Registration http://www.clinicaltrials.gov. Unique identifier: NCT00962416.