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Modeling heart valve annuli

Adarsh Krishnamurthy, Matthew J Gonzales, Gregory Sturgeon, W Paul Segars, Andrew D McCulloch
Cubic Hermite hexahedral finite element meshes have some well-known advantages over linear tetrahedral finite element meshes in biomechanical and anatomic modeling using isogeometric analysis. These include faster convergence rates as well as the ability to easily model rule-based anatomic features such as cardiac fiber directions. However, it is not possible to create closed complex objects with only regular nodes; these objects require the presence of extraordinary nodes (nodes with 3 or >= 5 adjacent elements in 2D) in the mesh...
March 2016: Computer Aided Geometric Design
Ellen Kuhl
Living systems can grow, develop, adapt, and evolve. These phenomena are non-intuitive to traditional engineers and often difficult to understand. Yet, classical engineering tools can provide valuable insight into the mechanisms of growth in health and disease. Within the past decade, the concept of incompatible configurations has evolved as a powerful tool to model growing systems within the framework of nonlinear continuum mechanics. However, there is still a substantial disconnect between the individual disciplines, which explore the phenomenon of growth from different angles...
January 2014: Journal of the Mechanical Behavior of Biomedical Materials
Michael Scharfschwerdt, Roza Meyer-Saraei, Claudia Schmidtke, Hans-Hinrich Sievers
OBJECTIVES: During implantation of transcatheter aortic valves into severe calcified aortic annuli, misdeployments due to asymmetric shapes of the target region were reported. Whether the resultant stent deformations influence valve performance has not been quantified. The objective of this study was to investigate in vitro hemodynamics of the Edwards Sapien XT (Edwards Lifesciences, Irvine, Calif) after valve deployment in noncircular aortic annuli. METHODS: Six Edwards Sapien XT valves were implanted into a model of the aortic annulus with different shapes (elliptical, triangular, and bulged compared with ideal circular) and investigated in a pulsatile flow simulator...
July 2014: Journal of Thoracic and Cardiovascular Surgery
Hyungseop Kim, Chiyoung Jung, Hyuck-Jun Yoon, Hyoung-Seob Park, Yun-Kyeong Cho, Chang-Wook Nam, Seung-Ho Hur, Yoon-Nyun Kim, Kwon-Bae Kim
BACKGROUND: Right ventricular function is associated with long-term outcomes of heart failure (HF), particularly with atrial fibrillation (AF). The aim of this study was to evaluate the prognostic value of Doppler tissue imaging at the mitral and tricuspid annuli in patients with HF and AF. METHODS: In this prospective observational study, 457 patients (mean age, 67 years; 283 men) referred for HF with AF were enrolled and underwent conventional echocardiography including pulsed-wave Doppler tissue imaging...
April 2012: Journal of the American Society of Echocardiography
Manuel K Rausch, Wolfgang Bothe, John-Peder Escobar Kvitting, Julia C Swanson, D Craig Miller, Ellen Kuhl
Mitral valve annuloplasty is a common surgical technique used in the repair of a leaking valve by implanting an annuloplasty device. To enhance repair durability, these devices are designed to increase leaflet coaptation, while preserving the native annular shape and motion; however, the precise impact of device implantation on annular deformation, strain, and curvature is unknown. In this article, we quantify how three frequently used devices significantly impair native annular dynamics. In controlled in vivo experiments, we surgically implanted 11 flexible-incomplete, 11 semi-rigid-complete, and 12 rigid-complete devices around the mitral annuli of 34 sheep, each tagged with 16 equally spaced tantalum markers...
March 2012: Annals of Biomedical Engineering
J Scott Rankin, L Alan Beavan, William E Cohn
OBJECTIVE: A need exists for a stable annuloplasty method for aortic valve repair. On the basis of a "hemispherical" model of aortic valve geometry, a prototype annuloplasty frame was constructed and initially tested. Specific goals were to develop a clinically applicable transaortic implant technique and to evaluate the system in isolated and intact animal preparations. METHODS: Eight isolated porcine aortic roots were perfused from a water reservoir at a constant pressure of 100 mm Hg, and valve leak was measured by timed collection in a beaker...
October 2011: Journal of Thoracic and Cardiovascular Surgery
Manuel K Rausch, Wolfgang Bothe, John-Peder Escobar Kvitting, Julia C Swanson, Neil B Ingels, D Craig Miller, Ellen Kuhl
The objective of this study is to establish a mathematical characterization of the mitral valve annulus that allows a precise qualitative and quantitative assessment of annular dynamics in the beating heart. We define annular geometry through 16 miniature markers sewn onto the annuli of 55 sheep. Using biplane videofluoroscopy, we record marker coordinates in vivo. By approximating these 16 marker coordinates through piecewise cubic splines, we generate a smooth mathematical representation of the 55 mitral annuli...
June 2011: Annals of Biomedical Engineering
Basar Candemir, Fatih Sinan Ertas, Cansin Tulunay Kaya, Cagdas Ozdol, Taner Hasan, Ozay Arikan Akan, Mustafa Sahin, Cetin Erol
BACKGROUND AND AIM OF THE STUDY: Mechanisms leading to vascular and tissue calcification are not yet fully understood. Previously, an association has been demonstrated between a controversial calcifying nanoparticle (CNP; also known as 'nanobacteria') and vascular calcification and kidney stone formation. The study aim was to evaluate a possible association between mitral annular calcification (MAC) and CNP infection. METHODS: A total of 93 patients with MAC, detected using echocardiography, and 94 asymptomatic subjects without valvular and coronary artery calcification, were enrolled in the study...
November 2010: Journal of Heart Valve Disease
Zhaoming He, Shamik Bhattacharya
BACKGROUND AND AIM OF THE STUDY: The mitral annulus mechanics associated with annular dilation in pathologies such as mitral valve (MV) prolapse, ischemic and dilative heart diseases remain unknown. The study aim was to investigate annulus tension (AT) in the dilated annulus and in the displaced papillary muscles due to these pathological conditions. METHODS: Ten porcine MVs were harvested and mounted on a MV closure test rig with the papillary muscles held in the slack, normal, and taut positions...
November 2010: Journal of Heart Valve Disease
Andrea Hutter, Anke Opitz, Sabine Bleiziffer, Hendrik Ruge, Ina Hettich, Domenico Mazzitelli, Albrecht Will, Peter Tassani, Robert Bauernschmitt, Ruediger Lange
OBJECTIVES: We compared the annulus diameters measured by transthoracic echocardiography (TTE), transesophageal echocardiography (TEE), and dual-source computed tomography (DSCT) before transcatheter aortic valve implantation (TAVI). BACKGROUND: In TAVI correct evaluation of the aortic annulus is mandatory to choose the correct prosthesis type and size and to prevent complications. There is no gold standard for the assessment of aortic annulus diameters. METHODS: Preoperative assessment of the aortic annulus with TTE, TEE, and DSCT was performed in 187 consecutive patients referred for TAVI between June 2007 and May 2009...
December 1, 2010: Catheterization and Cardiovascular Interventions
Sabine Bleiziffer, Hendrik Ruge, Jürgen Hörer, Andrea Hutter, Sarah Geisbüsch, Gernot Brockmann, Domenico Mazzitelli, Robert Bauernschmitt, Rüdiger Lange
OBJECTIVES: The aim of this study was to identify risk factors for new-onset atrioventricular (AV) block requiring pacemaker (PM) implantation after transcatheter aortic valve implantation (TAVI). BACKGROUND: High-grade AV block and consecutive PM implantation are frequent complications following TAVI. METHODS: For logistic regression analysis, we included 159 patients (mean age: 81 +/- 6 years, EuroSCORE: 22 +/- 13%) who underwent TAVI (n = 116 transfemoral, n = 4 via subclavian artery, n = 37 transapical, n = 2 transaortic) between June 2007 and January 2009 and who had no previously implanted PM...
May 2010: JACC. Cardiovascular Interventions
Hans Henrik Odland, Grete A B Kro, Thor Edvardsen, Erik Thaulow, Ola Didrik Saugstad
BACKGROUND: Global hypoxia may affect regions of the neonatal heart during systole and diastole differently. OBJECTIVE: In the first study, the aim was to assess longitudinal myocardial function in newborn pigs during global hypoxia and recovery. In the second study, invasive hemodynamic data were evaluated and compared with tissue velocities and acceleration. METHODS: Myocardial Doppler measurements of velocity and acceleration in the atrioventricular valve annuli during global hypoxia were made...
2010: Neonatology
Richard R Heuser, Thomas Witzel, Duane Dickens, Patricia A Takeda
AIMS: Percutaneous edge-to-edge techniques and annuloplasty have been used to treat mitral regurgitation (MR). However, neither intervention can be performed reliably a second time and, with annuloplasty, a foreign body is left behind. The mitral and tricuspid annuli are areas of dense collagen (Fig. 1); treatment with radiofrequency (RF) energy in sheep reduces their size, and can be repeated without affecting the coronary sinus. RF energy may also be used in leaflet procedures. Our aim was to improve mitral valve competence using techniques that can be incorporated into a minimally invasive approach...
April 2008: Journal of Interventional Cardiology
Ganesh Acharya, Juha Räsänen, Kaarin Mäkikallio, Tiina Erkinaro, Tomi Kavasmaa, Mervi Haapsamo, Luc Mertens, James C Huhta
We hypothesized that acute fetal metabolic acidosis decreases fetal myocardial motion in a chronic sheep model of increased placental vascular resistance (R(ua)). Eleven ewes and fetuses were instrumented at 118-122 days of gestation. After 5 days of recovery and 24 h of placental embolization to increase R(ua), longitudinal myocardial velocities of the right and left ventricles and interventricular septum (IVS) were assessed at the level of the atrioventricular valve annuli via tissue Doppler imaging (TDI)...
January 2008: American Journal of Physiology. Heart and Circulatory Physiology
Matthew A Allison, Dominic DiTomasso, Michael H Criqui, Robert D Langer, C Michael Wright
In this study we tested the hypothesis that calcium due to atherosclerosis in the renal arteries would be significantly associated with calcium in multiple other vascular beds, independent of traditional risk factors for cardiovascular disease (CVD). Electron beam computed tomography was conducted in 1461 consecutive asymptomatic patients free of clinical CVD to determine the presence and extent of calcium in the renal arteries, coronary and non-coronary vasculature and the aortic and mitral annuli. The overall prevalence for calcium in either renal artery was 18...
November 2006: Vascular Medicine
Angel López-Candales, Navin Rajagopalan, Beth Gulyasy, Kathy Edelman, Raveen Bazaz
BACKGROUND: Annular motion (AM) has been shown to occur during all dynamic phases of the cardiac cycle; but little is known regarding comparisons between mitral and tricuspid AM. We elected to use M-mode to examine the extent and timing of mitral and tricuspid AM events. METHODS: A complete echocardiogram was obtained in 50 patients [mean age 53 +/- 16 years, mean left ventricular ejection fraction (LVEF) 57 +/- 19%, and mean right ventricular fractional area change (RVFAC) of 49 +/- 20%]...
April 2007: Echocardiography
Jorge Hernan Jimenez, Dennis Dam Soerensen, Zhaoming He, Jennifer Ritchie, Ajit P Yoganathan
Since variations in annular motion/shape and papillary muscle displacement have been observed in studies of dilated cardiomyopathy and ischemic mitral regurgitation, the objective of this study was to investigate the effects of annular motion/flexibility and papillary muscle displacement on chordal force and mitral valve function. Six human mitral valves were studied in a left heart simulator using a flexible annular model. Mitral flow, trans-mitral pressure and chordae tendineae tension were monitored online in normal and pathophysiologic papillary muscle positions...
May 2005: Annals of Biomedical Engineering
Ivo Wolf, Raffaele De Simone, Mark Hastenteufel, Tobias Kunert, Sibylle Link, Hans-Peter Meinzer
Knowledge about annuli shape and blood flow patterns, both optimally assessed by transesophageal 3D Doppler echocardiography, can be used in computer assisted surgical planning of heart valve reconstruction. Moreover, information about the individual shape of the annulus anatomy can guide the design of annular prostheses. The problem is that the annulus cannot be easily differentiated from the valve and the myocardium with standard visualization methods. We have developed a nearly automatic method for annulus segmentation...
2002: Studies in Health Technology and Informatics
F H Sheehan, E L Bolson, J A McDonald
The authors' system for quantitative three-dimensional echocardiography (3D echo) now enables analysis of all four heart chambers, valves and associated structures. After image acquisition using freehand scanning and a magnetic field tracking device, the borders of cardiac structures are manually traced. Chambers are reconstructed with a piecewise smooth subdivision surface. The mitral and tricuspid annuli are fitted using a 4 term Fourier series. Other valves and orifices are reconstructed as ellipses. Anatomic labeling enables identification of the chordae, coronary sinus, intervalvular fibrosa, septum, and right and left ventricular apex...
2000: Computers in Cardiology
Joseph H Gorman, Robert C Gorman, Benjamin M Jackson, Yoshiharu Enomoto, Martin G St John-Sutton, L Henry Edmunds
BACKGROUND: Chronic ischemic mitral regurgitation (CIMR) is poorly understood and repair operations are often unsatisfactory. This study elucidates the mechanism of CIMR in an ovine model. METHODS: Sonomicrometry array localization measured the three-dimensional geometry of the mitral annulus and subvalvular apparatus in five sheep before and 8 weeks after a posterior infarction of the left ventricle that produced progressive severe CIMR. RESULTS: End systolic annular area increased from 647 +/- 44 mm(2) to 1,094 +/- 173 mm(2) (p = 0...
November 2003: Annals of Thoracic Surgery
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