Three dimensional reconstruction of coronary artery stents from optical coherence tomography: experimental validation and clinical feasibility

The structural morphology of coronary stents (e.g. stent expansion, lumen scaffolding, strut apposition, tissue protrusion, side branch jailing, strut fracture), and the local hemodynamic environment after stent deployment are key determinants of procedural success and subsequent clinical outcomes. High-resolution intracoronary imaging has the potential to enable the geometrically accurate three-dimensional (3D) reconstruction of coronary stents. The aim of this work was to present a novel algorithm for 3D stent reconstruction of coronary artery stents based on optical coherence tomography (OCT) and angiography, and test experimentally its accuracy, reproducibility, clinical feasibility, and ability to perform computational fluid dynamics (CFD) studies. Our method has the following steps: 3D lumen reconstruction based on OCT and angiography, stent strut segmentation in OCT images, packaging, rotation and straightening of the segmented struts, planar unrolling of the segmented struts, planar stent wireframe reconstruction, rolling back of the planar stent wireframe to the 3D reconstructed lumen, and final stent volume reconstruction. We tested the accuracy and reproducibility of our method in stented patient-specific silicone models using micro-computed tomography (μCT) and stereoscopy as references. The clinical feasibility and CFD studies were performed in clinically stented coronary bifurcations. The experimental and clinical studies showed that our algorithm (1) can reproduce the complex spatial stent configuration with high precision and reproducibility, (2) is feasible in 3D reconstructing stents deployed in bifurcations, and (3) enables CFD studies to assess the local hemodynamic environment within the stent. Notably, the high accuracy of our algorithm was consistent across different stent designs and diameters. Our method coupled with patient-specific CFD studies can lay the ground for optimization of stenting procedures, patient-specific computational stenting simulations, and research and development of new stent scaffolds and stenting techniques.

3D Reconstruction of Coronary Artery Stents From Optical Coherence Tomography: Experimental Validation and Clinical Feasibility

The structural morphology of stents (e.g. expansion, lumen scaffolding, strut apposition, tissue protrusion, side branch jailing, strut fracture), and the local hemodynamic environment after stent deployment in coronary arteries are key determinants of procedural success and subsequent clinical outcomes. High-resolution intracoronary imaging has the potential to enable the geometrically correct 3D reconstruction of coronary stents. The aim of this work was to present a novel algorithm for 3D stent reconstruction of coronary artery stents by OCT and angiography, and test experimentally its accuracy, reproducibility, clinical feasibility and ability to perform CFD studies. Our method has the following steps: 3D lumen reconstruction by OCT and angiography, stent strut segmentation on OCT images, packaging, rotation and straightening of the segmented struts, and planar unrolling of the segmented struts, planar stent wireframe reconstruction, rolling back of the planar stent wireframe to the 3D reconstructed lumen, and stent volume reconstruction. We tested the accuracy and reproducibility of our method in stented patient-specific silicone models using micro computed tomography and stereoscopy as reference. The clinical feasibility and CFD studies were performed in clinically stented coronary bifurcations. Our experimental and clinical studies showed that our proposed algorithm can reproduce the complex stent configuration in space with high precision and reproducibility. Furthermore, our studies showed that the algorithm is feasible in clinical cases with stents deployed in diseased, bifurcated coronary arteries, enabling CFD studies to assess the hemodynamic environment. Notably, the high accuracy of our algorithm was consistent across different stent designs and diameters. Our method coupled with patient-specific CFD studies can facilitate stenting optimization, training in stenting techniques, and stent research and development.

The Pivotal Role of Effective Communication in Patient Care: A Case of Coronary Stent Thrombosis

Myocardial infarction is a significant cause of morbidity and mortality worldwide, resulting in millions of percutaneous coronary interventions being performed yearly. Coronary artery stents are, however, at risk of thrombosis, with a significant mortality rate. Stent thrombosis is, however, preventable using dual antiplatelets, barring other procedural or unique personal predisposing characteristics. Good communication with patients is indispensable in ensuring adherence to dual antiplatelet therapy, protecting the patient from stent thrombosis. This paper presents a patient who discontinued his dual antiplatelet therapy prematurely and developed stent thrombosis within a week after discharge, highlighting the importance of good communication in promoting adherence to an agreed management plan.

Characterization of a Sandwich PLGA-Gallic Acid-PLGA Coating on Mg Alloy ZK60 for Bioresorbable Coronary Artery Stents

Absorbable magnesium stents have become alternatives for treating restenosis owing to their better mechanical properties than those of bioabsorbable polymer stents. However, without modification, magnesium alloys cannot provide the proper degradation rate required to match the vascular reform speed. Gallic acid is a phenolic acid with attractive biological functions, including anti-inflammation, promotion of endothelial cell proliferation, and inhibition of smooth muscle cell growth. Thus, in the present work, a small-molecule eluting coating is designed using a sandwich-like configuration with a gallic acid layer enclosed between poly (d,l-lactide-co-glycolide) layers. This coating was deposited on ZK60 substrate, a magnesium alloy that is used to fabricate bioresorbable coronary artery stents. Electrochemical analysis showed that the corrosion rate of the specimen was ~2000 times lower than that of the bare counterpart. The released gallic acid molecules from sandwich coating inhibit oxidation by capturing free radicals, selectively promote the proliferation of endothelial cells, and inhibit smooth muscle cell growth. In a cell migration assay, sandwich coating delayed wound closure in smooth muscle cells. The sandwich coating not only improved the corrosion resistance but also promoted endothelialization, and it thus has great potential for the development of functional vascular stents that prevent late-stent restenosis.