Search results for " heart valves"

Tailoring Electrospinning Fabrication for Scaffolds for Heart Valve Tissue Engineering

2010

Previous work in controlling mechanical properties of electrospun scaffolds has largely been limited to altering the orientation of the fibrous network by either large rotational velocity or by altering the electric field during fabrication. Our lab has previously developed a technique to analyze the complete microstructural topology of electrospun scaffolds and extract key descriptors. In this project, we translated the target mandrel at varying speeds along its rotational axis in order to modify the microarchitecture without altering the fiber orientation angle. Using the algorithm mentioned above, we determined that increasing the translation speed resulted in a decrease in fiber interse…

A MICRO-ARCHITECTURAL BASED STRUCTURAL MODEL FOR ELASTOMERIC ELECTROSPUN SCAFFOLDS FOR HEART VALVE TISSUE ENGINEERING

2010

BACKGROUND. Improving how scaffold architectures affect cell morphology, metabolism, phenotypic expression, and predicting mechanical behaviors, are crucial goals in the development of engineered heart valve scaffolds. Studies are required to elucidate how the fibrous microstructure translates into specific tissue (or meso-scale) level mechanical behavior. Deterministic structural models can quantify how key structures contribute to the mechanical response as a function of bulk deformation across multiple scales, as well as provide a better understanding of cellular mechanical response to local micro-structural deformations. An appropriate representative volume element (RVE) size was determ…

Anatomical and procedural features associated with aortic root rupture during balloon-expandable transcatheter aortic valve replacement

2013

Background— Aortic root rupture is a major concern with balloon-expandable transcatheter aortic valve replacement (TAVR). We sought to identify predictors of aortic root rupture during balloon-expandable TAVR by using multidetector computed tomography. Methods and Results— Thirty-one consecutive patients who experienced left ventricular outflow tract (LVOT)/annular/aortic contained/noncontained rupture during TAVR were collected from 16 centers. A caliper-matched sample of 31 consecutive patients without annular rupture, who underwent pre-TAVR multidetector computed tomography served as a control group. Multidetector computed tomography assessment included short- and long-axis diameters an…

Effects of Rastering Velocity on Electrospun Polyeurthane Structure and Mechanical Properties

2010

Incidence of thromboembolic complications in patients with mechanical heart valves with a subtherapeutic international normalized ratio.

2008

Objective Subtherapeutic international normalized ratios are frequently encountered in clinical practice, and patients with mechanical heart valves with inadequate anticoagulation may be exposed to an increased risk of thromboembolic events. There are no data on thromboembolic event risk for these patients. Methods We assessed the current practice patterns in the management of patients with mechanical heart valves with subtherapeutic international normalized ratios and assessed the risk of thromboembolic complications in this setting. The charts of patients with mechanical heart valves followed up in two anticoagulation clinics were reviewed. Patients with a history of stable, therapeutic a…

Long-Term Outcome with New Generation Prostheses in Patients Undergoing Transcatheter Aortic Valve Replacement

2021

The aim of this study was to compare patients with transcatheter aortic valve replacement (TAVR) receiving new generation prostheses SAPIEN 3 (S3, Edwards Lifesc.) and Evolut R (ER, Medtronic Inc.) in terms of periprocedural and long-term outcome. Our retrospective, single-center analysis included 359 consecutive patients with severe aortic stenosis who underwent TAVR with S3 or ER from 2014–2016 (mean age 82 ± 7 years, 47% male, mean EuroSCORE II 8.0 ± 8%, mean follow-up 3.8 years). Device Success was equal (S3 93.0% vs. ER 92.4%, p = 0.812). We report a 30-day mortality of 2.8% in the S3 group, and 2.1% in the ER group (p = 0.674). There was no difference in stroke, conversion to open sur…

Effect of Physiologic Oscillatory Fluid Shear Stress on Engineered Heart Valve Tissue Formation.

2010

It was previously demonstrated that combined flexure and flow in vitro conditioning augments engineered heart valve tissue formation using bone marrow-derived mesenchymal stem cells (MSC) seeded on polyglycolic acid (PGA)/poly-L-lactic acid (PLLA) blend nonwoven fibrous scaffolds (Engelmayr, et al., Biomaterials 2006; vol. 27 pp. 6083-95). Additionally, seeded scaffolds incorporated into a tissue engineered valve construct experienced significant increases in tissue formation rates with media supplementation (basic fibroblast growth factor [bFGF] and ascorbic acid-2-phosphate [AA2P]) and dynamic conditioning approximating pulmonary valve levels (Ramaswamy, et al., Biomaterials 2010; vol. 31…