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Valve Leaflets (valve + leaflet)

Distribution by Scientific Domains

Medical Sciences	88%

Kinds of Valve Leaflets

anterior mitral valve leaflet

mitral valve leaflet

Selected Abstracts

Fabrication of a Novel Hybrid Heart Valve Leaflet for Tissue Engineering: An In Vitro Study

ARTIFICIAL ORGANS, Issue 7 2009
Hao Hong
Abstract The objective of this study was to fabricate biomatrix/polymer hybrid heart valve leaflet scaffolds using an electrospinning technique and seeded by mesenchymal stem cells. Mesenchymal stem cells were obtained from rats. Porcine aortic heart valve leaflets were decellularized, coated with basic fibroblast growth factor/chitosan/poly-4-hydroxybutyrate using an electrospinning technique, reseeded, and cultured over a time period of 14 days. Controls were reseeded and cultured over an equivalent time period. Specimens were examined biochemically, histologically, and mechanically. Recellularization of the hybrid heart valve leaflet scaffolds was significantly improved compared to controls. Biochemical and mechanical analysis revealed a significant increase of cell mass, 4-hydroxyproline, collagen, and strength in the hybrid heart valve leaflets compared to controls. This is the first attempt in tissue-engineered heart valves to fabricate hybrid heart valve leaflets using mesenchymal stem cells combined with a slow release technique and an electrospinning technique. [source]

Percutaneous stent-mounted valve for treatment of aortic or pulmonary valve disease

CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 1 2004
John G. Webb MD
Abstract The objective of this study was to develop a prosthetic cardiac valve designed for percutaneous transcatheter implantation. Percutaneous catheter-based therapies play a limited role in the management of cardiac valve disease. Surgical implantation of prosthetic valves usually requires thoracotomy and cardiopulmonary bypass. The stent-valve is constructed of a rolled sheet of heat-treated nitinol. Although malleable when cooled, once released from a restraining sheath at body temperature the stent unrolls, becomes rigid, and assumes its predetermined cylindrical conformation. A ratcheting lock-out mechanism prevents recoil and external protrusions facilitate anchoring. Valve leaflets are constructed of bovine pericardium. The feasibility of catheter implantation, prosthetic valve function, and survival were investigated in an animal model. In vitro and pulse duplicator testing documented valve durability. Endovascular delivery of the prototype stent-valve to the aortic or pulmonary position was feasible. Accurate positioning was required to ensure exclusion of the native valve leaflets and, in the case of the aortic valve, to avoid compromise of the coronary ostia or mitral apparatus. Oversizing of the stent in relation to the valve annulus was desirable to facilitate anchoring and prevent paravalvular insufficiency. Stent-valve implantation proved feasible and compatible with survival in an animal model. Transcatheter implantation of prosthetic valves is possible. Further evolution of this technology will involve lower-profile devices with design features that facilitate vascular delivery, visualization, positioning, deployment, and valvular function. Catheter Cardiovasc Interv 2004;63:89,93. © 2004 Wiley-Liss, Inc. [source]

Staphylococcus aureus Infective Endocarditis Mimicking a Hydatid Cyst

ECHOCARDIOGRAPHY, Issue 8 2010
Jeroen Walpot M.D.
We report an atypical echocardiographic presentation of Staphylococcus aureus infective endocarditis (IE) of the mitral valve in an octogenarian female. Echocardiography revealed perforation of the anterior mitral valve leaflet (AMVL), with a large cystic mass seemingly attached to the AMVL and surrounded by a thin membranous structure. These images were strongly reminiscent of a hydatid cyst. The significant comorbidity of the patient did not justify an urgent surgical approach, and the patient subsequently expired of cardiogenic and septic shock. Autopsy revealed a large vegetation attached to the interatrial septum in the immediate proximity of the AMVL, without signs of the membranous structure and without pathological evidence for septic embolism. This atypical presentation of IE prompted us to discuss a brief review of intracardiac cystic masses. (Echocardiography 2010;27:E80-E82) [source]

Necrotizing Vasculitis: A Cause of Aortic Insufficiency and Conduction System Disturbance

ECHOCARDIOGRAPHY, Issue 7 2003
Miquel Gómez Pérez M.D.
Cardiac involvement in vasculitis syndromes is uncommon. We describe a 50-year-old male who presented with progressive dyspnea and myalgies. Echocardiogram revealed significant thickening of aortic root, aortic cusps, and anterior mitral valve leaflet, with severe aortic regurgitation that required aortic valve replacement. Furthermore, this patient suffered progressive atrioventricular block that needed implantation of a pacemaker. The study performed disclosed the presence of necrotizing vasculitis positive for perinuclear antineutrophil cytoplasmic antibody. (ECHOCARDIOGRAPHY, Volume 20, October 2003) [source]

Resistance to tearing of calf and ostrich pericardium: Influence of the type of suture material and the direction of the suture line

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 2 2004
José María García Páez
Abstract The tearing of the valve leaflet of a cardiac bioprosthesis can cause early failure of this device, which is employed to replace a diseased native valve. This report involves the study of the behavior of 312 tissue samples (152 of calf pericardium and 160 of ostrich pericardium) treated with glutaraldehyde and subsequently subjected to tear testing. The samples were cut in the two principal directions: longitudinally, or root to apex, and transversely. They included a series of control samples that were left unsutured, and the remaining samples were repaired with the use of two different suture techniques: a running suture in the direction of the load and a telescoping suture perpendicular to the load. Four commercially available suture materials were employed: Pronova®, nylon, Gore-Tex®, or silk. The unsutured control samples of both types of pericardium exhibited a similar anisotropic behavior in the tear test. The mean resistance to tearing of the calf pericardium was 24.29 kN m in samples cut longitudinally and 34.78 kN m in those cut transversely (p = .03); the values were 28.08 kN m and 37.12 kN m (p = .002), respectively, in ostrich pericardium. The series repaired with the telescoping suture always exhibited greater resistance to tearing, with values that ranged between 44.34 and 64.27 kN for the samples of calf pericardium and from 41.65 to 47.65 kN for those obtained from ostrich. These assays confirm the anisotropic behavior of calf and ostrich pericardium treated with glutaraldehyde when subjected to tear testing, as well as the loss of this behavior in ostrich pericardium after suturing. Suturing techniques, such as the telescoping model, that provide a greater resistance to tearing should be studied for use in the design of the valve leaflets of cardiac bioprostheses made of biological materials. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 69B: 125,134, 2004 [source]

Usefulness of Intraoperative Real-Time 3D Transesophageal Echocardiography in Cardiac Surgery

JOURNAL OF CARDIAC SURGERY, Issue 6 2008
Thierry V. Scohy M.D.
Methods: Preoperative transthoral echocardiography (TTE) revealed: hypertrophic ventricular septum (TTE:19.3 mm), systolic anterior motion (SAM) not causing obstruction and malcoaptation of the anterior mitral valve leaflet (AMVL), and posterior mitral valve leaflet (PMVL) with severe mitral regurgitation. Results: Intraoperative TEE with a x7-2t MATRIX-array transducer (Philips, Andover, MA, USA) with a transducer frequency of x7,2 t mHz, connected to a iE33 (Philips), shows us that the main mechanism and site of regurgitation was an AMVL cleft. We also measured a 24.3-mm thickness of the ventricular septum and analyzing the 3D full volume acquisition revealed that there was no SAM. Conclusion: Intraoperative RT3DTEE permitted comprehensive 3D viewing of the mitral valve revealing the mechanism of mitral valve regurgitation, SAM, and the exact width of the hypertrophic ventricular septum. [source]

AAIR Versus DDDR Pacing in the Bradycardia Tachycardia Syndrome: A Prospective, Randomized, Double-blind, Crossover Trial

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2001
BERNHARD SCHWAAB
SCHWABB, B., et al.: AAIR Versus DDDR Pacing in the Bradycardia Tachycardia Syndrome: A Prospective, Randomized, Double-blind, Crossover Trial. In 19 patients paced and medicated for bradycardia tachycardia syndrome (BTS), AAIR and DDDR pacing were compared with regard to quality of life (QoL), atrial tachyarrhythmia (AFib), exercise tolerance, and left ventricular (LV) function. Patients had a PQ interval , 240 ms during sinus rhythm, no second or third degree AV block, no bundle branch block, or bifascicular block. In DDDR mode, AV delay was optimized using the aortic time velocity integral. After 3 months, QoL was assessed by questionnaires, patients were investigated by 24-hour Holter, cardiopulmonary exercise testing (CPX) was performed, and LV function was determined by echocardiography. QoL was similar in all dimensions, except dizziness, showing a significantly lower prevalence in AAIR mode. The incidence of AFib was 12 episodes in 2 patients with AAIR versus 22 episodes in 7 patients with DDDR pacing (P = 0.072). In AAIR mode, 164 events of second and third degree AV block were detected in 7 patients (37%) with pauses between 1 and 4 seconds. During CPX, exercise duration and work load were higher in AAIR than in DDDR mode (423 ± 127 vs 402 ± 102 s and 103 ± 31 vs 96 ± 27 Watt, P < 0.05). Oxygen consumption (VO2), was similar in both modes. During echocardiography, only deceleration of early diastolic flow velocity and early diastolic closure rate of the anterior mitral valve leaflet were higher in DDD than in AAI pacing (5.16 ± 1.35 vs 3.56 ± 0.95 m/s2 and 69.2 ± 23 vs 54.1 ± 26 mm/s, P < 0.05). As preferred pacing mode, 11 patients chose DDDR, 8 patients chose AAIR. Hence, AAIR and DDDR pacing seem to be equally effective in BTS patients. In view of a considerable rate of high degree AV block during AAIR pacing, DDDR mode should be preferred for safety reasons. [source]

Tissue Engineered Heart Valves: Autologous Cell Seeding on Biodegradable Polymer Scaffold

ARTIFICIAL ORGANS, Issue 5 2002
Toshiharu Shinoka
Abstract: We previosly reported on the successful creation of tissue-engineered valve leaflets and the implantation of these autologous tissue leaflets in the pulmonary valve position. Mixed cell populations of endothelial cells and fibroblasts were isolated from explanted ovine arteries. Endothelial cells were selectively labeled with an acetylated low-density lipoprotein marker and separated from fibroblasts using a fluorescent activated cell sorter. A synthetic biodegradable scaffold consisting of polyglycolic acid fibers was seeded first with fibroblasts then subsequently coated with endothelial cells. Using these methods, autologous cell/polymer constructs were implanted in 6 animals. In 2 additional control animals, a leaflet of polymer was implanted without prior cell seeding. In each animal, using cardiopulmonary bypass, the right-posterior leaflet of the pulmonary valve was resected completely and replaced with an engineered valve leaflet with (n = 6) or without (n = 2) prior cultured cell seeding. After 6 h and 1, 6, 7, 9, and 11 weeks, the animals were sacrificed and the implanted valve leaflets were examined histologically, biochemically, and biomechanically. Animals receiving leaflets made from polymer without cell seeding were sacrificed and examined in a similar fashion after 8 weeks. In the control animals, the acellular polymer leaflets were degraded completely leaving no residual leaflet tissue at 8 weeks. The tissue-engineered valve leaflet persisted in each animal in the experimental group; 4-hydroxyproline analysis of the constructs showed a progressive increase in collagen content. Immunohistochemical staining demonstrated elastin fibers in the matrix and factor VIII on the surface of the leaflet. The cell labeling experiments demonstrated that the cells on the leaflets had persisted from the in vitro seeding of the leaflets. In the tissue-engineered heart valve leaflet, transplanted autologous cells generated proper matrix on the polymer scaffold in a physiologic environment at a period of 8 weeks after implantation. [source]

Late Presentation of Pulmonary Valve Stenosis Confirmed by Cardiovascular Magnetic Resonance

CONGENITAL HEART DISEASE, Issue 3 2008
Didier Locca MD
ABSTRACT We describe the case of a 70-year-old man who presented with increasing exertional dyspnea. He was found to have an ejection systolic murmur and evidence of right ventricular outflow tract obstruction, with a peak velocity of 4.5 m/s recorded by transthoracic Doppler echocardiography. Cardiovascular magnetic resonance showed right ventricular hypertrophy, pulmonary valve stenosis, peak recorded velocity 4.2 m/s, with thickened pulmonary valve leaflets of reduced mobility, and poststenotic dilatation of the main pulmonary artery. The case illustrates that severe pulmonary valve stenosis can present late in life and that cardiovascular magnetic resonance can be useful in clarifying nature and level of right ventricular outflow tract obstruction in an adult. [source]

Aortic Valve Sclerosis: Is It a Cardiovascular Risk Factor or a Cardiac Disease Marker?

ECHOCARDIOGRAPHY, Issue 3 2007
F.I.S.C.U., Pasquale Palmiero M.D.
Background: Aortic valve sclerosis, without stenosis, has been associated with an increased cardiovascular mortality and morbidity due to myocardial infarction. However, it is unclear whether it is a cardiovascular risk factor or a cardiac disease marker. The goal of our study is to evaluate the difference in the prevalence of cardiovascular disease and risk factors among patients with or without aortic sclerosis. Methods: This observational study compared a group of 142 consecutive subjects with aortic valve sclerosis, assigned as group S, with a group of 101 subjects without aortic sclerosis, assigned as group C. Patients with bicuspid aortic valves and those with antegrade Doppler velocity across aortic valve leaflets exceeding 2.0 m/sec were excluded. Results: Mean ages of groups S and C were 71 ± 8, and 68.8 ± 6 years, respectively (P value = not significant). The prevalence of smoking, diabetes, hypercholesterolemia, hypertension, pulse pressure, left ventricular diastolic dysfunction, atrial fibrillation, and stroke was not significantly different between the two groups. However, there was a significantly higher prevalence of left ventricular hypertrophy (P = 0.05), ventricular arrhythmias (P = 0.02), myocardial infarction (P = 0.04), and systolic heart failure (P = 0.04) in aortic sclerosis group. Conclusions: Aortic sclerosis is associated with a higher prevalence of left ventricular hypertrophy, ventricular arrhythmias, myocardial infarction, and systolic heart failure, while the prevalence of cardiovascular risk factors is not different between aortic sclerosis patients and controls. Hence, aortic sclerosis represents a cardiac disease marker useful for early identification of high-risk patients beyond cardiovascular risk factors rate. [source]

Transesophageal and Transpharyngeal Ultrasound Demonstration of Reversed Diastolic Flow in Aortic Arch Branches and Neck Vessels in Severe Aortic Regurgitation

ECHOCARDIOGRAPHY, Issue 4 2004
Deepak Khanna M.D.
In the current study, we describe an adult patient with torrential aortic regurgitation due to an aortic dissection flap interfering with aortic cusp motion, in whom a transesophageal echocardiogram with the probe positioned in the upper esophagus and transpharyngeal ultrasound examination demonstrated prominent reversed flow throughout diastole in the left subclavian, left vertebral, left common carotid, and left internal carotid arteries. Another unique finding was the demonstration of aortic valve leaflets held in the fully opened position in diastole by the dissection flap as it prolapsed into the left ventricular outflow tract, dramatically documenting the mechanism of torrential aortic regurgitation in this patient. (ECHOCARDIOGRAPHY, Volume 21, May 2004) [source]

Fibrotic Aortic Stenosis in a Patient with Dwarfism

ECHOCARDIOGRAPHY, Issue 7 2000
Wen Ying Huang M.D.
In this report, we present an adult patient with dwarfism who had severe aortic stenosis with markedly thickened fibrotic valve leaflets without calcification. These findings were well demonstrated by both two- and three-dimensional transesophageal echocardiography and confirmed at surgery and by pathological examination. [source]

Resistance to tearing of calf and ostrich pericardium: Influence of the type of suture material and the direction of the suture line

Cardiac amyloidosis: MR imaging findings and T1 quantification, comparison with control subjects

JOURNAL OF MAGNETIC RESONANCE IMAGING, Issue 6 2007
Gabriele A. Krombach MD
Abstract In cardiac amyloidosis an interstitial deposition of amyloid fibrils causes concentric thickening of the atrial and ventricular walls. We describe the results of tissue characterization of the myocardium by T1 quantification and MRI findings in a patient with cardiac amyloidosis. The T1 time of the myocardium was elevated compared to that in individuals without amyloidosis. The T1 time of the myocardium was 1387 ± 63 msec (mean value obtained from four measurements ± standard deviation [SD]) in the patient with cardiac amyloidosis, while the reference value obtained from the myocardium of 10 individuals without known myocardial disease was 1083 ± 33 msec (mean value ± SD). In combination with other MR findings suggestive of amyloidosis, such as homogeneous thickening of the ventricular and atrial walls, thickening of the valve leaflets, restrictive filling pattern, and reduction of systolic function, T1 quantification may increase diagnostic confidence. J. Magn. Reson. Imaging 2007;25:1283,1287. © 2007 Wiley-Liss, Inc. [source]

Prospective Evaluation of the Balloon-to-Annulus Ratio for Valvuloplasty in the Treatment of Pulmonic Stenosis in the Dog

JOURNAL OF VETERINARY INTERNAL MEDICINE, Issue 4 2006
Amara Estrada
Background: In dogs, treatment of pulmonic valve stenosis (PS) with pulmonary balloon valvuloplasty (PBV) is a viable method to decrease the pressure gradient across the valve. However, to the authors' knowledge, the variables that influence the selection of the correct balloon size for the procedure have not been explored. Moreover, the lesions caused by the procedure have not been detailed. Hypothesis: Variables that influence the measurement of the annulus could affect selection of the balloon size. We sought to determine the effects of treatment when the balloon-to-annulus ratio (BAR) was or > 1.3, but within the recommended range of 1.2,1.5, regardless of whether dilation was performed with single or double balloon technique. Animals: Twenty-five Beagles with PS were studied. Methods: Inter-and intra-observer variability, echocardiography versus angiocardiography, and systolic versus diastolic timing were evaluated for the BAR. Assessment of right ventricular (RV) pressure, Doppler gradient, stenotic valve area, and RV wall thickness were compared before and 1, 90, and 180 days after treatment. Postmortem examination of the heart was done. Results: Significant correlations existed in measurement of the annulus; however, variation existed that would change balloon size. Improvement in the degree of PS was significant regardless of the BAR or single or double ballooning. In the most severely affected dogs, continued improvement was noted on day 90. Postmortem examination revealed tears in the commissures and the valve leaflets. Conclusions: Multiple factors influenced determination of the BAR and a range of 1.2,1.5 was effective without detrimental consequences. Dogs with severe PS had continued decrease in RV pressure 3 months after treatment. [source]