Nano-crush technique in narrow-angle (<70°) bifurcation: bench test, CT reconstruction, fluid dynamics, and clinical outcomes.

Background: Bifurcation stenting techniques are still refining and under testing. Nano-crush is a novel technique which allow minimum protrusion of side branch struts at the ostium. To demonstrate the efficacy of Nano-crush technique in narrow-angle bifurcation (<70°) using bench test model, 3D reconstruction of the stent structure, computational fluid dynamics study and a clinical follow-up.

Methods: This was a retrospective observational single-center study which included 40 patients who underwent angioplasty using Nano-crush technique for de-novo complex coronary bifurcation lesions with narrow bifurcation angle (<70°) between April-2016 to March-2019. The in-vitro bench test and computational fluid dynamics analysis were performed using a bifurcation model designed. The clinical primary endpoint was major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, and target lesion revascularization (TLR) at one-year angiographic follow-up.

Results: The reconstructed results of in-vitro bench test showed minimum length of stent struts moving away from the rounded side branch ostium. The mean age of patients was 62.8±7.98 years (32 male) and presented 100% procedural success. The mean bifurcation angle was 47.3±9.2°. The MACE was reported in four (10%) patients which included one (2.5%) death and three (7.5%) TLR at the mean follow-up of 35.54±12.31 months. No significant correlation between occurrence of MACE and gender, age, comorbidities and bifurcation angle was reported.

Conclusions: The Nano-crush technique demonstrated least metal load around carina and abnormal flow dynamics in narrow angle (<70°) bifurcation lesions and also reported favorable long-term clinical outcomes.