Provisional Stenting for the Treatment of Bifurcation Lesions: In Vitro Insights

Provisional stenting is considered the gold standard approach for most bifurcation lesions, but the benefit of routine side branch (SB) strut dilatation has not been fully elucidated. A benchtop model was used to determine the benefits of routine side branch (SB) dilatation techniques on strut apposition, acute thrombogenicity, and flow disruption. Three different provisional bifurcation techniques were compared: no SB dilatation “keep it open” method (KIO), sequential balloon dilatation (SBD), and kissing balloon inflation (KBI). Stents were deployed in a silicon bifurcation model and perfused with blood at a flow rate of 200 ml/min for 60 min. Optical coherence tomography (OCT) pullbacks were obtained before and after flow perfusion to conduct strut analysis and acute thrombus measurement respectively. Computational fluid dynamics (CFD) models were created using OCT pullbacks and simulated based on experimental conditions to analyze flow disruption. The strut analysis showed that KBI had the lowest percentage of floating (10.6 ± 2.3%) (p = 0.0004) and malapposed (41.2 ± 8.5%) struts (p = 0.59), followed by SBD and then KIO. This correlated to KBI having the lowest amount of thrombus formed at the SB, followed by SBD, with KIO being the most thrombogenic (KBI: 0.84 ± 0.22mm ², SBD: 1.17 ± 0.25mm ², KIO: 1.31 ± 0.36mm ², p = 0.18). CFD models also predicted a similar trend, with KBI having the lowest amount of area of high shear rate as well as flow recirculation. Based on this benchtop model, SB intervention strategies demonstrated a reduction in number of struts and resulting thrombogenicity at the bifurcation ostia. [Figure not available: see fulltext.]