Post-dilatation improves stent apposition in patients with ST-segment elevation myocardial infarction receiving primary percutaneous intervention: A multicenter,randomized controlled trial using optical coherence tomography

BACKGROUND: Stent failure is more likely in the lipid rich and thrombus laden culprit lesions underlying ST-segment elevation myocardial infarction(STEMI).This study assessed the effectiveness of post-dilatation in primary percutaneous coronary intervention(pPCI) for acute STEMI.METHODS: The multi-center POST-STEMI trial enrolled 41 consecutive STEMI patients with symptom onset <12 hours undergoing manual thrombus aspiration and Promus Element stent implantation.Patients were randomly assigned to control group(n=20) or post-dilatation group(n=21) in which a non-compliant balloon was inflated to >16 atm pressure.Strut apposition and coverage were evaluated by optical coherence tomography(OCT) after intracoronary verapamil administration via thrombus aspiration catheter, post pPCI and at 7-month follow-up.The primary endpoint was rate of incomplete strut apposition(ISA) at 7 months after pPCI.RESULTS: There were similar baseline characteristics except for stent length(21.9 [SD 6.5] mm vs.26.0 [SD 5.8] mm, respectively, P=0.03).In post-dilatation vs.control group, ISA rate was lower(2.5% vs.4.5%, P=0.04) immediately after pPCI without affecting final TIMI flow 3 rate(95.2% vs.95.0%, P>0.05) or corrected TIMI frame counts(22.6±9.4 vs.22.0±9.7, P>0.05); and at 7-month follow-up(0.7% vs.1.8%, P<0.0001), the primary study endpoint, with similar strut coverage(98.5% vs.98.4%, P=0.63) and 1-year rate of major adverse cardiovascular events(MACE).CONCLUSION: In STEMI patients, post-dilatation after stent implantation and thrombus aspiration improved strut apposition up to 7 months without affecting coronary blood flow or 1-year MACE rate.Larger and longer term studies are warranted to further assess safety(Clinical Trials.gov identifier: NCT02121223).