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.