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 of care for provisional stenting, but it induces mechanical injury. Drug-coated balloons (DCBs) may pharmacologically inhibit neointimal hyperplasia to improve long-term patency.

AIMS: We sought to evaluate mechanistic vascular healing and luminal changes of the SB after adjunctive SB-DCB versus SB-conventional balloon treatment using high-resolution serial optical coherence tomography (OCT).

METHODS

The randomised OCVC-BIF trial compared adjunctive SB-DCB (n=149) with non-DCB treatment (n=150) following main vessel stenting and protocolled KBI. The present prespecified study was restricted to those patients who completed analysable follow-up OCT pullbacks (n=221). Endpoints included the SB volume change and the main vessel stent healing parameters.

RESULTS

There was no significant difference in the ostium, minimum SB area, or SB volume between the DCB and non-DCB groups following percutaneous coronary intervention (PCI). Serial OCT analysis showed that the DCB group exhibited a lumen volume gain at the SB of 0.14±5.64 mm3 from post-PCI to 9-month follow-up, whereas the non-DCB group showed a mean loss of 2.15±9.51 mm3. Although this difference reached statistical significance in the prespecified parametric analysis (p=0.042), in the sensitivity analysis using the Wilcoxon rank-sum test, the difference was attenuated (0.45 [interquartile range [IQR] -3.83, 4.00] in DCB vs -0.65 [IQR -5.00, 2.50] in non-DCB; p=0.093). While in the DCB group, the 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 towards preservation of the SB lumen. These findings may support the mechanistic feasibility of this strategy in selected bifurcation lesions. (Japan Registry of Clinical Trials: jRCTs052200077).