Bioresorbable magnesium scaffold in the treatment of simple coronary bifurcation lesions: The BIFSORB pilot II study

Objectives: To evaluate the feasibility, safety, and healing response of a magnesium-based bioresorbable scaffold (BRS) in the treatment of simple bifurcation lesions using the single stent provisional technique.

Background: BRS may hold potential advantages in the treatment of coronary bifurcation lesions, however low radial strength and expansion capacity has been an issue with polymer-based scaffolds. The magnesium BRS may prove suitable for bifurcation treatment as its mechanical properties are closer to those of permanent metallic drug-eluting stents.

Methods: The study was a proof-of-concept study with planned inclusion of 20 patients with stable angina pectoris and a bifurcation lesion involving a large side branch (SB) > 2.5 mm with less than 50% diameter stenosis. Procedure and healing response were evaluated by optical coherence tomography (OCT). The main endpoints were a composite clinical safety endpoint and an OCT healing index at 1 month (range: 0-98).

Results: Eleven patients were included in the study. The study was prematurely terminated due to scaffold fractures and embolization of scaffold fragments in three cases requiring bailout stenting with drug-eluting stents. One patient underwent bypass surgery at 3 months due to stenosis proximal to the study segment. All SB were patent for 1 month. One-month OCT evaluation showed strut coverage of 96.9% and no malapposition. Scaffold fractures and uncovered jailing struts resulted in a less favorable mean OCT healing index score of 10.4 ± 9.0.

Conclusions: Implanting a magnesium scaffold by the provisional technique in nontrue bifurcation lesions was associated with scaffold fracture, embolization of scaffold fragments, and a high need for bailout stenting.