Decoding In-Stent Restenosis: A Single Center Experience

Aim: The current study aims to investigate the underlying mechanisms contributing to the development of in-stent restenosis (ISR), the effectiveness of various treatment approaches, and the role of advanced imaging techniques in its diagnosis and management. The study focuses on providing comprehensive insights to improve patient care and clinical outcomes in ISR cases.

Study Design: Retrospective observational monocentric study.

Place and Duration of Study: Apollo Hospitals, Chennai on 50 patients with ISR from April 2022 to October 2023

Methodology: Patients with prior percutaneous coronary intervention (PCI) presenting with ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI), unstable angina, positive stress tests, or revascularization failure in bare metal stent (BMS) or drug eluting stent (DES) were included. Exclusions were coronary artery bypass grafting (CABG), non-drug-coated balloons, left main restenosis, thrombus, or early restenosis within three months. The primary outcome, major adverse cardiovascular events (MACE), was a composite of cardiovascular death, target lesion revascularization (TLR), target vessel revascularization (TVR), and myocardial infarction (MI).

Results: Analysis of ISR mechanisms showed stent under-expansion in 48% of cases with stent boost. On imaging Neo-intimal hyperplasia was found in 20%, and neoatherosclerosis in 14% of patients. The imaging group had a significant reduction in MACE. Most patients (78%) received DES, while 22% received Drug coated balloon (DCB), with no significant outcome differences between them. Additionally, ticagrelor or prasugrel use in ISR patients significantly reduced event rates.

Conclusion: Our findings suggest that imaging-guided PCI can significantly reduce the incidence of major adverse cardiac events. Additionally, potent P2Y12 inhibitors like ticagrelor and prasugrel may offer superior outcomes to clopidogrel in ISR patients. While both adequate lesion preparation using ELCA or specialty balloons and understanding the mechanism of ISR using imaging followed by DCB or DES or combining both demonstrated fairly similar outcomes in our study with a slight inclination towards imaging and ELCA for better long term results, further research and large number of studies is needed to assess their relative efficacy in ISR definitively.