Drug-coated versus conventional balloons for side branch treatment in coronary bifurcation lesions: an optical coherence tomography substudy of the OCVC-BIF randomised trial.

BACKGROUND: Coronary bifurcation lesions remain prone to side-branch (SB) ostial restenosis. Kissing balloon inflation (KBI) is the standard for provisional stenting but induces mechanical injury. Drug-coated balloons (DCB) may pharmacologically inhibit neointimal hyperplasia to improve long-term patency. AIMS: To evaluate mechanistic vascular healing and luminal changes at the SB after adjunctive SB-DCB versus SB-conventional balloon treatment using high-resolution serial optical coherence tomography (OCT). METHODS: The randomized OCVC-BIF trial compared adjunctive SB-DCB (n=149) to Non-DCB (n=150) following main-vessel stenting and protocolled KBI. The present pre-specified study was restricted to those patients who completed evaluable follow-up OCT pullbacks (n=221). Endpoints included the SB volume change and the main vessel stent healing parameters. Although difference reached statistical significance in the prespecified parametric analysis (p=0.042), in sensitivity analysis using the Wilcoxon rank-sum test, the difference was attenuated (0.45 [-3.83, 4.00] in DCB vs -0.65 [-5.00, 2.50] in Non-DCB, p=0.093). While in the DCB group, SB lumen volume change from immediately after PCI to follow-up was not statistically significant (p=0.81), the Non-DCB group demonstrated a statistically significant reduction in SB lumen volume (p=0.03). At 9 months, the incidence of uncovered and malapposed struts was low and comparable between groups across all segments. CONCLUSIONS: Adjunctive SB-DCB treatment after KBI showed no adverse effect on main-vessel stent healing and a possible signal toward preservation of SB lumen. These findings may support the mechanistic feasibility of this strategy in selected bifurcation lesions. (Japan Registry of Clinical Trials: 052200077).