Better vascular healing of ultrathin strut biodegradable-polymer sirolimus-eluting stents in patients with acute coronary syndrome

This study aimed to compare the strut coverage between Orsiro ultrathin struts biodegradable polymer sirolimus-eluting stents (O-SES) and Xience thin struts durable polymer everolimus-eluting stents (X-EES) in acute coronary syndrome (ACS) patients using optical coherence tomography (OCT). In BIOSTEMI trial, O-SESs were superior to X-EESs with respect to target lesion failure (TLF) in ACS patients. However, there were few reports comparing intravascular imaging between the two stents in ACS. Between August 2016 and February 2020, 50 lesions from 50 ACS patients who underwent OCT-guided percutaneous coronary intervention (PCI) were enrolled. We compared mid-term vascular healing using OCT between O-SESs and X-EESs at 8-month after stenting. The protocol was approved by the Osaka Rosai Hospiral ethics committee. Among 50 lesions, the X-EES group consisted of 25 lesions and the O-SES of 25 lesions. The percentage of covered strut, the percentage of malapposed strut and mean neointimal thickness at 8-month were evaluated. In the 8-month OCT analysis, the proportion of covered strut was significantly higher in the O-SES group than in in the X-EES group (97.3% vs. 86.0%; p = 0.001). On the other hand, there were no significant differences in the frequency of malapposed strut (0.4% vs 1.0%, p = 0.238). The O-SES group had the tendency of thinner neointima compared to the X-EES group (60µm vs 76µm, p = 0.089). Compared to X-EESs, O-SESs showed better mid-term vascular healing and tended to have thinner neointima in ACS patients. Ultra-thin strut may play a key role in better vascular healing.