Cardiac Valve Identification Atlas and Guide

Morse, Dryden P.; Steiner, Robert M.

doi:10.1007/978-1-4612-5096-8_10

Cited by 10 publications

(2 citation statements)

References 47 publications

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“…Their design used Teflon strips to link the chordae tendinae. When Dr Braunwald identified the device susceptibility to fibrous connective tissue infiltration, she considered applying Teflon to the metal ball could reduce thrombogenesis [ 1 , 2 ].…”

Section: Introductionmentioning

confidence: 99%

Normal function of a 43-year-old Braunwald Cutter heart valve

Jiménez‐Rodrìguez

Críales-Vera

Juárez-Peñaloza

et al. 2018

Oxford Medical Case Reports

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We present the case of a 72-year-old woman diagnosed with rheumatic fever at the age of 6. In 1972, she was diagnosed with mitral valve insufficiency and mitral valve stenosis, then in 1974, a decision was made to perform mitral valve replacement surgery with a 32-mm Braunwald-Cutter ball cage prosthesis. An echocardiogram performed in 2014 revealed normal biventricular systolic function, mechanical prosthesis in mitral position with maximum speed of 1.9 m/s, maximum gradient of 15 mmHg, mean gradient of 6 mmHg, severe tricuspid valve insufficiency, inferior vena cava measuring 15 mm with more than 50% collapse and pulmonary artery systolic pressure of 40 mmHg. We report the use of the 32-mm Braunwald-Cutter ball cage prosthesis with the longest longevity that remains functional after more than 43 years of implantation.

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Section: Introductionmentioning

confidence: 99%

Normal function of a 43-year-old Braunwald Cutter heart valve

Jiménez‐Rodrìguez

Críales-Vera

Juárez-Peñaloza

et al. 2018

Oxford Medical Case Reports

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“…Barium Sulfate (BaSO 4 ) has been used as a radio‐opaque agent in several implanted medical devices 13, 14. It appears ‘white’ during X‐ray screening, making it easy for doctors to track the implant.…”

Section: Introductionmentioning

confidence: 99%

Effect of radio‐opaque filler on biodegradable stent properties

Chan

Bini

Venkatraman

et al. 2006

J Biomedical Materials Res

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The effect of the addition of a radio-opaque filler, barium sulfate (BaSO(4)), on the mechanical properties of a biodegradable amorphous polymer film (poly-lactic-co-glycolic acid, PLGA) was studied, as a function of degradation. With up to about 18% loading (v/v), the modulus of the filled polymer increases; beyond this concentration, agglomerates are formed. The filled systems are also radio-opaque, over a thickness range of 0.07-0.19 mm in stent form (helicoidal). These stents were then immersed in phosphate buffer pH 7.4 at 37(o)C for 2 weeks. The radial strength of stent was measured by using a compression test. It was found that filler-loaded stent (FS) increased in radial strength by about 4 times (14.95 +/- 1.20 N/mm) compared to the unfilled stent (UFS). However, both samples lost radial strength as the polymer degraded in buffer, but FS retained 60% (9.05 +/- 0.07 N/mm) of its strength after 2 weeks whereas only 36% (1.39 +/- 1.04 N/mm) was retained for UFS. Moreover, UFS lost its helical shape after 3 weeks. The findings have implications for optimization of degradable stent formulations.

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Tissue heart valves: Current challenges and future research perspectives

Schoen¹,

Levy²

1999

J. Biomed. Mater. Res.

408

215

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Substitute heart valves composed of human or animal tissues have been used since the early 1960s, when aortic valves obtained fresh from human cadavers were transplanted to other individuals as allografts. Today, tissue valves are used in 40% or more of valve replacements worldwide, predominantly as stented porcine aortic valves (PAV) and bovine pericardial valves (BPV) preserved by glutaraldehyde (GLUT) (collectively termed bioprostheses). The principal disadvantage of tissue valves is progressive calcific and noncalcific deterioration, limiting durability. Native heart valves (typified by the aortic valve) are cellular and layered, with regional specializations of the extracellular matrix (ECM). These elements facilitate marked repetitive changes in shape and dimension throughout the cardiac cycle, effective stress transfer to the adjacent aortic wall, and ongoing repair of injury incurred during normal function. Although GLUT bioprostheses mimic natural aortic valve structure (a) their cells are nonviable and thereby incapable of normal turnover or remodeling ECM proteins; (b) their cuspal microstructure is locked into a configuration which is at best characteristic of one phase of the cardiac cycle (usually diastole); and (c) their mechanical properties are markedly different from those of natural aortic valve cusps. Consequently, tissue valves suffer a high rate of progressive and age-dependent structural valve deterioration resulting in stenosis or regurgitation (>50% of PAV overall fail within 10-15 years; the failure rate is nearly 100% in 5 years in those <35 years old but only 10% in 10 years in those >65). Two distinct processes-intrinsic calcification and noncalcific degradation of the ECM-account for structural valve deterioration. Calcification is a direct consequence of the inability of the nonviable cells of the GLUT-preserved tissue to maintain normally low intracellular calcium. Consequently, nucleation of calcium-phosphate crystals occurs at the phospholipid-rich membranes and their remnants. Collagen and elastin also calcify. Tissue valve mineralization has complex host, implant, and mechanical determinants. Noncalcific degradation in the absence of physiological repair mechanisms of the valvular structural matrix is increasingly being appreciated as a critical yet independent mechanism of valve deterioration. These degradation mechanisms are largely rationalized on the basis of the changes to natural valves when they are fabricated into a tissue valve (mentioned above), and the subsequent interactions with the physiologic environment that are induced following implantation. The "Holy Grail" is a nonobstructive, nonthrombogenic tissue valve which will last the lifetime of the patient (and potentially grow in maturing recipients). There is considerable activity in basic research, industrial development, and clinical investigation to improve tissue valves. Particularly exciting in concept, yet early in practice is tissue engineering, a technique in which an anatomically appropriate construct con...

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Cardiac Valve Identification Atlas and Guide

Cited by 10 publications

References 47 publications

Normal function of a 43-year-old Braunwald Cutter heart valve

Normal function of a 43-year-old Braunwald Cutter heart valve

Effect of radio‐opaque filler on biodegradable stent properties

Tissue heart valves: Current challenges and future research perspectives

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