Post-operative echocardiographic evaluation of bioprosthetic mitral valve implantation in sheep

Abstract

The ovine model is generally considered to be the best for testing bioprosthetic heart valve durability. Although echocardiography is the method of choice for the interim evaluation of the valve, literature on sheep echocardiography is scarce. Within the context of a study on treatment of pericardial heart valve prostheses, 19 adolescent sheep underwent transthoracic echocardiography six days after mitral implantation of bioprosthetic valves. Echocardiographic examination was performed under mild anesthesia and animals were put in a right lateral decubitus position. Four images were obtained: right parasternal long axis four and five chamber views, right parasternal long axis view with left ventricular outflow, and right parasternal short axis view through the mitral valve. We measured aortic annulus and velocity time integral over the aortic valve to determine stroke volume, cardiac output and cardiac index. The mitral valve was evaluated through color Doppler imaging for valvular and paravalvular leakages. Pulsed wave spectral Doppler was used for the measurement of velocities, pressures and velocity time integrals. For the evaluation of valve stenosis deceleration time and pressure half-time were determined. Effective orifice area of the mitral valve was derived. And, although not measured, other structures could clearly be visualized: right and left ventricle and atrium, wall thicknesses, tricuspid valve. This study shows that echocardiography in sheep is feasible, and that right parasternal images, obtained in animals in a right lateral decubitus position, are well qualified for the interim evaluation of bioprosthetic valves implanted in the mitral position. Besides the implanted valve, other cardiac structures like atria and ventricles can be visualized and evaluated.

A novel tissue treatment to reduce mineralization of bovine pericardial heart valves

“…Transthoracic echocardiography was conducted at 1 week, 5 weeks, and 20 weeks postimplantation using previously described methods. 16 At death, a necropsy was performed and radiographs of the explanted device conducted. Heart and valve pathology were evaluated macroscopically and by histologic examination (hematoxylin and eosin and Von Kossa staining) by an independent pathologist.…”

Anatomical Similarities Between Mitral and Tricuspid Valves in Sheep, Ovis aries, Hearts

“…Twenty-five sheep hearts were obtained from Carolina Biological Supply (Burlington, NC). Sample size was estimated to account for variability in anatomy and size of the heart using previously published studies 5 . Hearts with any damage at the time of harvesting were excluded, and all dissections were performed by SSK and SRK.…”

Bacterial cellulose as a promising material for pulmonary valve prostheses: In vivo study in a sheep model

“…Because previous studies showed the excellent biocompatibility of BC, 13 in accordance with our earlier published method, 14 and euthanasia was carried out after 7 months.…”