Comparison of long-term outcome in patients with in-stent restenosis treated with intravascular lithotripsy or with modified balloon angioplasty

Background: Modified balloon angioplasty (MB) using a cutting-/scoring balloon or intravascular lithotripsy (IVL) is used in patients with in-stent restenosis (ISR). However, IVL is an off-label use in this setting. The aim of this subgroup analysis of an all-comers registry was to compare IVL to MB angioplasty in patients with ISR.Methods: The subgroup (n = 117) included all patients with an ISR treated by MB or IVL between 2019 and 2021. Primary endpoint was strategy success (< 20% residual stenosis). The secondary endpoint was cardiac death, acute myocardial infarction (AMI) and target lesion failure/revascularization (TVR). Quantitative coronary angiography was performed in all patients.Results: A total of n = 36 patients were treated by IVL and n = 81 patients by MB. No significant differences in baseline characteristics were observed between the groups. The primary endpoint was reached in 99 patients (84.6%). Patients in the IVL group had less residual stenosis (2.8% vs. 21.0%; p = 0.012). Multivariate regression analysis revealed that IVL had a significant positive effect on reaching the primary end point (Estimate 2.857; standard error (SE) 1.166; p = 0.014). During the follow-up period (450 days) there were no significant differences in rates of cardiac death (IVL n = 2 (1.7%) vs. MB n = 3 (2.6%); p = 0.643), AMI (IVL n = 2 (1.7%) vs. MB n = 4 (3.4%); p = 0.999) and TVR (IVL n = 5 (4.3%) vs. MB n = 14 (12%); p = 0.851).Conclusion: IVL results in a significantly lower rate of residual stenosis than MB in patients with ISR. During the long-term follow-up, no differences in rates of cardiac death, AMI or TVR were observed.