Side branch fractional flow reserve measurements after main vessel stenting: A Nordic-Baltic Bifurcation Study III substudy

Aims: The substudy was performed to evaluate the acute and eight-month follow-up effect of final kissing balloon dilatation (FKBD) on fractional flow reserve (FFR) in the side branch (SB) after main vessel (MV) stenting. Methods and results: We included 75 patients in the Nordic-Baltic Bifurcation Study III FFR substudy: 42 in the FKBD group and 33 in the no-FKBD group. Complete angiographic and FFR eight-month follow-up was obtained in 25 (60%) patients in the FKBD group and 21 (63%) patients in the no-FKBD group. In the FKBD group the post-PCI mean SB FFR was significantly higher compared to the no-FKBD group (0.92 vs. 0.85, respectively; p=0.011). No significant difference in FFR value between treatments was detected at eight-month follow-up (0.91 vs. 0.87; p=0.19). There were no significant changes in mean SB FFR during the follow-up period (0.92 vs. 0.91; p=0.80) in the FKBD group and (0.87 vs. 0.87; p=0.91) in the no-FKBD group. Conclusions: FKBD in simple stenting of bifurcation lesions improved acute functional outcome in SB compared to leaving the SB jailed. No significant difference was detected at follow-up. In both groups there was no significant functional late loss during follow-up. Thus, both strategies were equally effective in ensuring that side branch jailing would not cause ischaemia in the long term.