A Patient-Specific Study Investigating the Relation between Coronary Hemodynamics and Neo-Intimal Thickening after Bifurcation Stenting with a Polymeric Bioresorbable Scaffold

Susanna Migliori,Marco Bologna,David Hildick-Smith,Rajiv Rampat,James Cockburn,Francesco Burzotta,Claudio Chiastra,Luca Mainardi,Eros Montin,Gabriele Dubini,Francesco Migliavacca

doi:10.3390/app8091510

Abstract

We present an application of a validated reconstruction methodology for the comparison between patient-specific hemodynamics and neo-intimal thickening at nine months from the intervention. (1) Background: Coronary bifurcation stenting alters the vessel geometry, influencing the local hemodynamics. The evaluation of wall shear stress (WSS) relies on the application of computational fluid dynamics to model its distribution along the coronary tree. The endothelium actively responds to WSS, which triggers eventual cell proliferation to cover the stent struts. (2) Methods: Baseline optical coherence tomography and angiographic data were combined to reconstruct a patient-specific coronary bifurcation with an implanted bioresorbable scaffold and to simulate the hemodynamics. Results were linked with the neo-intimal thickening after nine months from the intervention. (3) Results: Blood velocity patterns were disrupted at the bifurcation due to the presence of the stent. It was observed that 55.6% of the scaffolded lumen surface was exposed to values of time-averaged WSS lower than 0.4 Pa. Follow-up images showed a luminal narrowing of 19% in the main branch. There was also a complete coverage in 99% of struts. (4) Conclusions: This approach provided valuable complementary information that might improve the clinical outcomes in this subset of coronary diseases.

Highlights

A coronary stent is a wire mesh or cut tubular structure inserted into a stenosed or blocked coronary artery to improve blood flow to the myocardium subtended by that artery
One method to quantify strut coverage is by measuring the neo-intimal thickening (NIT), defined as the perpendicular distance between the midpoint of the adluminal strut surface and the inner luminal surface measured on optical coherence tomography (OCT) images [2]
Blood flow into the diagonal branch was disrupted by the presence of the scaffold over the orifice, flow into the diagonal branch was disrupted by the presence of the scaffold over the orifice, leading

Summary

Introduction

A coronary stent is a wire mesh or cut tubular structure inserted into a stenosed or blocked coronary artery to improve blood flow to the myocardium subtended by that artery. Bioresorbable coronary devices have been developed, seeking to overcome the limitations of the state-of-the-art drug-eluting permanent stents, including the risks of target lesion revascularization, neo-atherosclerosis, hindrance of late lumen enlargement, and the lack of reactive vasomotion in the stented vessel [1]. One method to quantify strut coverage is by measuring the neo-intimal thickening (NIT), defined as the perpendicular distance between the midpoint of the adluminal strut surface and the inner luminal surface measured on optical coherence tomography (OCT) images [2] Another method is to calculate the restenosis area, defined as the difference between the scaffold area and the sum of the strut and luminal area at a particular cross-section of the OCT on follow-up imaging. The incidence of adverse neointimal hyperplastic response may be predicted using surrogate quantities, such as a low WSS averaged over one cardiac cycle (

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