Degenerative processes in bioprosthetic mitral valves in juvenile pigs

Abstract

BackgroundGlutaraldehyde-treated bioprosthetic heart valves are commonly used for replacement of diseased heart valves. However, calcification and wear limit their durability, and the development of new and improved bioprosthetic valve designs is needed and must be evaluated in a reliable animal model. We studied glutaraldehyde-treated valves 6 months after implantation to evaluate bioprosthetic valve complications in the mitral position in juvenile pigs.MaterialsThe study material comprised eight, 5-month old, 60-kg pigs. All pigs received a size 27, glutaraldehyde-treated, stented, Carpentier-Edwards S.A.V. mitral valve prosthesis. After six months, echocardiography was performed, and the valves explanted for gross examination, high resolution X-ray, and histological evaluation.ResultsFive pigs survived the follow-up period. Preexplant echocardiography revealed a median peak and mean velocity of 1.61 m/s (range: 1.17-2.00) and 1.20 (SD = ±0.25), respectively, and a median peak and mean pressure difference of 10.42 mmHg (range: 5.83-16.55) and 6.51 mmHg (SD = ±2.57), respectively. Gross examination showed minor thrombotic depositions at two commissures in two valves and at all three commissures in three valves. High resolution X-ray imaging revealed different degrees of calcification in all explanted valves, primarily in the commissural and belly areas. In all valves, histological evaluation demonstrated various degrees of fibrous sheath formation, limited immunological infiltration, and no overgrowth of host endothelium.ConclusionsBioprosthetic glutaraldehyde-treated mitral valves can be implanted into the mitral position in pigs and function after 6 months. Echocardiographic data, calcification, and histological examinations were comparable to results obtained in sheep models and human demonstrating the suitability of the porcine model.

The analysis of oauses of bioprosthetio valve dysfunction: the example of «UniLine» bioprosthesis

“…Отсутствие кальцификатов в местах скопления клеток, а также отсутствие клеток вблизи мелких кальцификатов ставит под сомнение первостепенную роль клеток реципиента в процессе кальцификации. Аналогичные результаты были получены Honge et al (2011) [15]. Таким образом, присутствие в ткани биопротеза клеток можно рассматривать как проблему дегенеративных изменений биоматериала без кальцификации.…”

Impact on porcine heart valve tissue treating with carbodiimide

“…Bioprostheses are produced from aortic valves -trileaflet, implantation is very similar to aortic. There were studies that show calcification of these aortic bioprosthesis cusps calcification after implantation in mitral valve position [6]. But again in this study aortic trileaflet valve was used.…”

Modern understanding of mechanisms of bioprosthetic valve structural degeneration: a literature review

“…Как правило, крупные клеточные инфильтраты и выраженный воспалительный ответ наблюдается в базальной части протеза, особенно, на контакте тканей донора и реципиента. Эта закономерность характерна как для людей [21], так и для животных моделей [27].…”