Comparison of Side-Branch Dilation Techniques After Resorbable Magnesium Scaffold Implantation: A Bench Study.

BACKGROUND

The resorbable magnesium scaffold (RMS) has demonstrated a good safety profile to treat de novo lesions. Nevertheless, bifurcation lesions involving a side branch (SB) >2.0 mm in diameter were excluded from these studies, and such lesions remain technically challenging due to concerns of scaffold deformation or fracture. We sought to evaluate different SB dilation strategies after provisional T-stenting strategy with RMS using silicon bifurcation phantoms.

METHODS AND RESULTS

Three different strategies were compared: proximal optimization technique (POT)-side-rePOT (rePOT), kissing-balloon inflation (KBI), and mini kissing-balloon inflation (MKBI) strategies. Strut and connector fractures were evaluated by micro computed tomography and apposition by optical coherence tomography (OCT). Twelve Magmaris scaffolds (Biotronik) were successfully implanted (4 in each group). There was no difference in strut and connector fractures among the three techniques, as no fracture was visualized. OCT demonstrated that MKBI significantly decreased global malapposition following SB inflation as compared with rePOT or KBI strategies (95.3% vs 88.3% of perfectly apposed struts [P<.001] and 93.6% [P<.01], respectively, for MKBI vs rePOT and KBI). After step-by-step over-expansion of 6 RMS devices with 3.75 mm, 4.0 mm, and 4.5 mm NC balloons at 16 atm (ie, +1.5 mm from the initial 3.0 mm RMS), no strut or connector fracture could be visualized.

CONCLUSION

Provisional single-stent technique with the Magmaris RMS on a bifurcation lesion is technically feasible with these three different strategies without scaffold fracture. MKBI strategy resulted in better apposition rates as compared with KBI or rePOT strategies. Nevertheless, Magmaris use in bifurcation lesions should not be advised before similar results are confirmed by in vivo studies.