Hemodynamics of Stent Implantation Procedures in Coronary Bifurcations: an in vitro study

Stent implantation in coronary bifurcations presents unique challenges and currently there is no universally accepted stent deployment approach. Despite clinical and computational studies, to date, the effect of each stent implantation method on the coronary artery hemodynamics is not well understood. In this study the hemodynamics of stented coronary bifurcations under pulsatile flow conditions were investigated experimentally. Three implantation methods, provisional side branch (PSB), culotte (CUL), and crush (CRU), were investigated using time-resolved particle image velocimetry (PIV) to measure the velocity fields. Subsequently, hemodynamic parameters including wall shear stress (WSS), oscillatory shear index (OSI), and relative residence time (RRT) were calculated and the pressure field through the vessel was non-invasively quantified. The effects of each stented case were evaluated and compared against an un-stented case. CRU provided the lowest compliance mismatch, but demonstrated detrimental stent interactions. PSB, the clinically preferred method, and CUL maintained many normal flow conditions. However, PSB provided about a 300% increase in both OSI and RRT. CUL yielded a 10% and 85% increase in OSI and RRT, respectively. The results of this study support the concept that different bifurcation stenting techniques result in hemodynamic environments that deviate from that of un-stented bifurcations, to varying degrees.Comment: 33 pages, 8 figures, 3 table

Percutaneous Valve-in-Valve Treatment of a (Very Old and Fluoroscopy Invisible) Degenerated Tricuspid Prosthesis Through the Right Jugular Vein Approach

Tricuspid valve dysfunction adversely affects prognosis and may cause severe symptoms. Among the different opportunity offered by transcatheter techniques, the valve in valve represents an emerging strategy to treat patients with degenerated surgical biological prosthesis. We describe a case report of a percutaneous valve in valve treatment of a very old and fluoroscopy invisible tricuspid degenerated bioprosthesis. In the reported case, pivotal issue for percutaneous valve in valve procedure success was the achievement of perfect alignment between transcatheter valve and degenerated bioprosthesis despite the horizontal right chamber axis and the poor valve visibility. Of note, the combination of jugular vein approach, transapical delivery system rotation, right ventricle guidewire placement, and right atrium angiography made the valve in valve procedure safely

Right coronary artery patency as a modulator for unprotected left main PCI risk: myth or reality?

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An Unusual Treatment of Atrial Fibrillation Percutaneous Exclusion of a Large Coronary Aneurysm

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Randomized comparison between 3-month Cre8 DES vs. 1-month Vision/Multilink8 BMS neointimal coverage assessed by OCT evaluation: The DEMONSTRATE study

AbstractBackgroundIt has been hypothesized that incomplete endothelialization and delayed vascular healing may trigger stent thrombosis events after drug-eluting stent (DES) implantation. We aimed to demonstrate non-inferiority in terms of neointimal coverage of novel Cre8 DES at 3months, compared to Vision/Multilink8 Bare Metal Stent (BMS) at 1month.MethodsThe ranDomizEd coMparisOn betweeN novel Cre8 DES and BMS to assess neoinTimal coveRAge by OCT Evaluation (DEMONSTRATE) was a multicenter, randomized, parallel group study. Thirty-eight patients undergoing angioplasty of de-novo coronary lesion were randomized to Cre8 (19) or Vision/Multilink8 (19) stent placement at 6 OCT-experienced centers. Primary end-point was the Ratio of Uncovered to Total Stent Struts Per Cross Section (RUTTS) score of <30%, determined by OCT at 3 and 1months for Cre8 and Vision/Multilink8, respectively. Percentage of uncovered/malapposed stent struts, neointimal growth and thickness were the main secondary end-points.ResultsThe primary end-point of RUTTS score <30% occurred in 99.8% (899/901) of Cre8 struts and in 99.6% (1116/1121) of Vision/Multilink8 struts (difference 0.2, CI 95% −0.2 to 0.6, p for noninferiority <0.001). The percentage of uncovered/malapposed struts was comparable (0.36±0.64 vs. 0.12±0.24, p=0.145) in the two study groups, while both neointimal percentage area (8.46±5.29 vs. 19.84±15.93, p<0.001) and thickness (0.07±0.04 vs. 0.16±0.12, p<0.001) were significantly reduced by Cre8 stent.ConclusionsThe Cre8 DES at 3months has comparable strut coverage to Vision/Multilink8 BMS at 1month while preserving a greater efficacy in neo-intima formation reduction. Further studies to assess clinical implication of these Cre8 characteristics are warranted

Dr. Albert P. Marshall, Oral History Interview, 1998

Dr. Albert P. Marshall served Eastern Michigan University from 1969 until 1980, during which time he taught library science, served as Library Director and Dean of Academic Services. This interview serves as a comprehensive biography of Marshall, from childhood through his time as Dean of Academic Services at Eastern Michigan University. Notable are Marshall’s experiences as librarian for the United States Coast Guard before arriving at EMU, and his concern for the welfare of black students at Eastern. This interview was conducted for the purpose of gathering primary research for Laurence Smith’s book, Eastern Michigan University: A Sesquicentennial Portrait (1999).https://commons.emich.edu/oral_histories/1006/thumbnail.jp

A framework for computational fluid dynamic analyses of patient-specific stented coronary arteries from optical coherence tomography images

The clinical challenge of percutaneous coronary interventions (PCI) is highly dependent on the recognition of the coronary anatomy of each individual. The classic imaging modality used for PCI is angiography, but advanced imaging techniques that are routinely performed during PCI, like optical coherence tomography (OCT), may provide detailed knowledge of the pre-intervention vessel anatomy as well as the post-procedural assessment of the specific stent-to-vessel interactions. Computational fluid dynamics (CFD) is an emerging investigational tool in the setting of optimization of PCI results. In this study, an OCT-based reconstruction method was developed for the execution of CFD simulations of patient-specific coronary artery models which include the actual geometry of the implanted stent. The method was applied to a rigid phantom resembling a stented segment of the left anterior descending coronary artery. The segmentation algorithm was validated against manual segmentation. A strong correlation was found between automatic and manual segmentation of lumen in terms of area values. Similarity indices resulted >96% for the lumen segmentation and >77% for the stent strut segmentation. The 3D reconstruction achieved for the stented phantom was also assessed with the geometry provided by X-ray computed micro tomography scan, used as ground truth, and showed the incidence of distortion from catheter-based imaging techniques. The 3D reconstruction was successfully used to perform CFD analyses, demonstrating a great potential for patient-specific investigations. In conclusion, OCT may represent a reliable source for patient-specific CFD analyses which may be optimized using dedicated automatic segmentation algorithms

Local fluid dynamics in patients with bifurcated coronary lesions undergoing percutaneous coronary interventions

Although the coronary arteries are uniformly exposed to systemic cardiovascular risk factors, atherosclerosis development has a non-random distribution, which follows the local mechanical stresses including flow-related hemodynamic forces. Among these, wall shear stress plays an essential role and it represents the major flow-related factor affecting the distribution of atherosclerosis in coronary bifurcations. Furthermore, an emerging body of evidence suggests that hemodynamic factors such as low and oscillating wall shear stress may facilitate the development of in-stent restenosis and stent thrombosis after successful drug-eluting stent implantation. Drug-eluting stent implantation represents the gold standard for bifurcation interventions. In this specific setting of interventions on bifurcated lesions, the impact of fluid dynamics is expected to play a major role and constitutes substantial opportunity for future technicalimprovement. In the present review, available data is summarized regarding the role of local fluid dynamics in the clinical outcome of patients with bifurcated lesions

Composite Y internal thoracic artery–saphenous vein grafts: short-term angiographic results and vasoreactive profile

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