Serial Optical Coherence Tomography Observations following Newer-Generation Drug-Eluting Stents That Combine Ultrathin Struts and Nanocoating in Patients with ST-Elevation Myocardial Infarction after Plaque Rupture

Newer-generation drug-eluting stents (DES) that combine ultrathin struts and nanocoating (biodegradable polymer sirolimus-eluting stents, BP-SES) could improve vascular healing in patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) over previous DES. However, its time course has not been elucidated.Patients with STEMI caused by plaque rupture who underwent primary PCI at our institution using BP-SES between June 2018 and August 2020 were eligible. Vascular responses were assessed by frequency-domain optical coherence tomography (OCT), which was serially performed before the final angiography (post-PCI), after 2 weeks (2W-OCT) and 1 year (1Y-OCT).A total of 24 patients with STEMI were finally assessed. The percentage of uncovered struts declined significantly at 1 year (post-PCI 61.7 ± 20.0%; 1Y-OCT 3.3 ± 3.3%; P < 0.0001). The percentage of malapposed struts also decreased significantly (% malapposed struts: post-PCI; 4.1 ± 3.6%: 1Y-OCT; 1.0 ± 2.3%, P< 0.0001). On the other hand, a total of 9 patients (37.5%) had at least 1 portion (> 3 mm length) of persistent malapposition (16.7%), late acquired malapposition (4.2%), or coronary evagination (16.7%) at 1 year. The site of late acquired malapposition was mostly at the culprit site, while the sites of persistent malapposition and evagination were not. None of the lesions showed signs of stent thrombosis.In conclusion, BP-SES implanted into culprit plaque ruptures in patients with STEMI showed fast vascular healing in the chronic phase, while subclinical malappositions and evaginations were not rare and showed dynamic changes.