Background: 

Debulking balloon angioplasty (DBA) using a cutting or scoring balloon is commonly used in patients with calcified coronary arteries. Intravascular lithotripsy (IVL) is often used in the treatment of in-stent restenosis (ISR). However, this is an off-label use. The aim of this subgroup analysis of a two-center, all-comers registry was to compare the safety and effectiveness of IVL to that of DBA in patients with ISR.

Methods: 

The cohort (n=117) included all patients with an ISR treated by DBA or IVL between 2019 and 2021. The primary endpoint was strategy success (<20% residual stenosis). The secondary endpoint was long-term safety outcomes. Quantitative coronary angiography was performed in all patients. 

Results:  

A total of n=36 patients were treated by IVL and n=81 patients by DBA. 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 (5.8% 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 (Odds Ratio (OR) 17.4); standard error (SE) 1.166; P=0.014). Further, patients with severe calcification had a lower probability for reaching the primary endpoint (Estimate -1.838 (OR 0.16); SE 0.705; P=0.009). The use of a drug coated balloon (P=0.693) or a drug eluting stent (P=0.693), as well as predilatation pressure (P=0.804) or postdilatation pressure (P=0.902), stent length (P=0.309) and stent diameter (P=0.841) had no effect on the primary endpoint.

During the follow-up period (450 days) there was no significant difference in cardiovascular mortality rate (IVL n=2 (1.7%) vs. DBA n=3 (2.6%); P=0.643; IVL Hazard ratio (HR) 1.6; 95% Confidence interval (CI) 0.27-9.51); P=0.612). No significant differences were found in long-term rate of acute myocardial infarction (IVL n=2 (1.7%) vs. DBA n=4 (3.4%); P=0.999; IVL HR 1.13 CI 95% 0.21-6.20; P=0.89) and target lesion failure/revascularization (IVL n=5 (4.3%) vs. DBA n=14 (12%); P=0.851; IVL HR 0.79 CI 95% 0.29-2.20; P=0.653). 

Conclusion: 

IVL results in a significantly lower rate of residual stenosis than DBA in patients with an ISR. During the long-term follow-up, no differences in cardiovascular mortality, occurrence of acute myocardial infarction or target lesion failure/revascularization were observed.