Provisional T-stenting with bailout side branch (SB) stenting is used to treat most coronary bifurcation stenoses.

To evaluate, in vitro, two bailout side branch stenting techniques after failed provisional T-stenting. We aimed to compare flows and stent strut apposition of T And Protrusion (TAP) versus Reversed String (RS) bailout techniques using a flow simulator, optical coherence tomography (OCT), in silicon bifurcation phantoms with different angulations between branches.

Ten 30°-angle and ten 60°-angle silicon bifurcation phantoms were used. After performing provisional T-stenting, TAP and RS techniques were compared in 5 phantoms with 30° and 60° angles. Flow measurement was performed using absolute coronary flow and particle image velocimetry techniques. Strut apposition was evaluated using OCT (Fig. 1).

Each case was successfully performed and completed. Longer fluoroscopy time in the RS group compared to the TAP group (404±137 vs. 267±47seconds; P=0.043) was observed. Flow analyses showed that disturbed flow regions were observed in the vicinity of floating struts protruded into the lumen both regardless of TAP and RS techniques. OCT analysis showed a higher proportion of floating struts protruding into the main branch with TAP compared to RS, respectively (12% vs. 3%; P=0.009) in both angles (11% vs. 1% with 60°; P=0.006 and 13% vs. 6% with 30°; P=0.15).

RS reduces the proportion of floating struts protruding into the main branch compared to TAP, at comparable flow rates. Clinical studies are needed to evaluate feasibility and potential clinical benefit of this technique.