Bail-out stenting and target-vessel failure after drug-coated balloon percutaneouS coronary angioplasty for de novo lesions: The BOSS study

• In BOSS study, bail-out stenting in case of de novo DCB PCI is associated with higher rate of 1-year target vessel revascularization. • The observed effect on the primary endpoint is predominantly attributable to target vessel-myocardial infarction. • Patients enrolled in the study predominantly received small vessel PCI. The median reference vessel diameter was indeed 2.5 mm in both groups. • The use of imaging-guided PCI was modest, but no events related to the primary endpoint occurred in patients with BOS who received it. In BOSS study, bail-out stenting in case of de novo DCB PCI is associated with higher rate of 1-year target vessel revascularization. The observed effect on the primary endpoint is predominantly attributable to target vessel-myocardial infarction. Patients enrolled in the study predominantly received small vessel PCI. The median reference vessel diameter was indeed 2.5 mm in both groups. The use of imaging-guided PCI was modest, but no events related to the primary endpoint occurred in patients with BOS who received it. Drug-coated balloon (DCB) percutaneous coronary intervention (PCI) for de-novo lesions represents a valid alternative to drug-eluting-stents in different settings. Bail-out stenting (BOS) might be applied to manage acute vessel recoil or dissections, however, its impact on clinical endpoints remains unclear. This study sought to investigate the 1-year outcomes of BOS compared to DCB-only PCI. The present study was a multicenter, ambispective, investigator-initiated all-comer study enrolling PCI patients treated with DCB at 11 hospitals. Patients were divided into two groups: those who received DCB-only treatment and those who required BOS. Primary endpoint was 12-month target-vessel-failure (TVF) defined as a composite of target-vessel-myocardial infarction (TV-MI) and ischemia driven-target vessel revascularization (ID-TVR). The study included 1085 patients and 1236 lesions. BOS occurred in 11.1% of patients. The two study groups were well balanced in terms of clinical characteristics and angiographic features. Most of the lesions involved small vessels (median RVD 2.5 mm [IQR 2.0–2.5 mm]) and were classified as intermediate-high anatomical complexity (41% type B2/C). At 12-month, the occurrence of TVF was 3.2%. The primary endpoint occurred more frequently in BOS group (6.7% vs 2.8%, p -value = 0.02;), mostly due to TV-MI (4.2% vs 0.9%, p-value = 0.01). On multivariable analysis, BOS was still independently associated with the risk of the primary endpoint. (HR 2.70; 95%CI: 1.22–5.98: p-value = 0.015). After DCB-PCI the need for bail-out stenting is an independent risk factor of TVF at 1 year. Operators should anticipate BOS as a higher-risk scenario, imaging optimization may mitigate risks.