Nano-crush technique in narrow angle (<70˚) bifurcation - bench test, computed tomographic 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-centre 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 4 (10%) patients which included 1 (2.5%) death and 3 (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.