The Design and Feasibility of Optimal Treatment for Coronary Drug-Eluting Stent In-Stent Restenosis (OPEN-ISR)-A Prospective, Randomised, Multicentre Clinical Trial.

Percutaneous coronary intervention (PCI) with drug-eluting stents (DES) is a cornerstone of the management of ischemic heart disease. However, in-stent restenosis (ISR) remains a significant clinical challenge, occurring in approximately 5-10% of patients undergoing PCI. This study is designed to compare the efficacy and safety of the primary therapeutic approaches for DES-ISR, specifically drug-coated balloons (DCBs)-paclitaxel-coated balloons (PCBs) and sirolimus-coated balloons (SCBs)-with a new-generation everolimus-eluting stent (EES), contributing to the evolving field of personalized medicine. This prospective, multicentre, randomised, non-inferiority trial aims to enroll 150 patients with DES-ISR, who will be randomised into one of the following: SCB, PCB, or EES. The primary endpoint comparing DCB and EES is late lumen loss (LLL) at 6 months, as measured by quantitative coronary angiography (QCA). Secondary endpoints comparing the three arms include a device-oriented composite endpoint, intraluminal gain, optical coherence tomography (OCT) measured LLL, and correlations between LLL and quantitative flow ratio (QFR). The primary endpoint will be analysed using a non-inferiority design, with a margin set at 0.25 mm, for which the sample size was calculated. Statistical analysis of the primary endpoint will be conducted on an intention-to-treat basis with a one-tailed Mann-Whitney U test with a significance level of 95. Secondary endpoints will be analysed via superiority testing using ANOVA, the Kruskal-Wallis test, logistic regression, or Fisher's exact test, as appropriate. The study protocol has been approved by the Medical Devices Department of the Hungarian National Institute of Pharmacy and Nutrition, ensuring compliance with ethical standards as outlined in the Declaration of Helsinki. All investigators declare no conflicts of interest related to this study. The trial is registered in ClinicalTrials.gov under the ID: NCT04862052.