Crescenzo D G, Hilbert S L, Messier R H, Domkowski P W, Barrick M K, Lange P L, Ferrans V J, Wallace R B, Hopkins R A
Georgetown University School of Medicine, Washington, DC.
Ann Thorac Surg. 1993 Jan;55(1):25-30; discussion 30-1. doi: 10.1016/0003-4975(93)90469-x.
Twenty-five human cryopreserved valves with harvest-related warm ischemic times (WITs) ranging from 0 to 20 hours were studied using transmission electron microscopy to characterize the effects of harvesting and preservation on leaflet matrix cells. The valves were divided into seven groups on the basis of WIT and processed using standard transmission electron microscopic methods. Each cell (528 micrographs) was graded for reversible and irreversible cellular injury and subjected to a Cochran-Mantel-Haenszel trend analysis. Our results demonstrated a progression in cellular injury with increasing WIT. During the first 12 hours of warm ischemia, reversible cellular injury predominated (0.0%, 30.0%, 51.2%, 31.3%, 35.1%, 45.1%, and 40.0% at WITs of 0, 1, 2, 8, 12, 16, and 20 hours, respectively). A positive correlation (p < 0.0001) between increasing WIT and reversible cellular injury through the first 12 hours was observed. Minimal morphologic evidence of irreversible injury was noted in valves harvested with less than 12 hours of warm ischemia; however, after 12 hours there was a marked increase (0.0%, 0.0%, 4.7%, 2.4%, 2.7%, 31.4%, and 40.0% at WITs of 0, 1, 2, 8, 12, 16, and 20 hours, respectively) in irreversible cellular injury (p < 0.001 between 12 and 20 hours WIT). These data demonstrate a progression in cellular injury with increasing WIT. There was virtually no morphologic injury in valves with harvest-related WITs less than 2 hours and minimal irreversible cellular injury observed in valves exposed to 12 hours or less of warm ischemia. If cellular viability is critical to homograft durability then harvest-related warm ischemia may need to be restricted to 12 hours.
对25个与收获相关的热缺血时间（WIT）为0至20小时的人冷冻保存瓣膜进行了研究，采用透射电子显微镜来表征收获和保存对瓣叶基质细胞的影响。根据WIT将瓣膜分为七组，并使用标准透射电子显微镜方法进行处理。对每个细胞（528张显微照片）进行可逆性和不可逆性细胞损伤分级，并进行Cochran-Mantel-Haenszel趋势分析。我们的结果表明，随着WIT增加，细胞损伤呈进展性变化。在热缺血的前12小时，可逆性细胞损伤占主导（在WIT为0、1、2、8、12、16和20小时时，分别为0.0%、30.0%、51.2%、31.3%、35.1%、45.1%和40.0%）。观察到在前12小时内，WIT增加与可逆性细胞损伤之间存在正相关（p < 0.0001）。在热缺血时间少于12小时收获的瓣膜中，不可逆损伤的形态学证据极少；然而，12小时后，不可逆性细胞损伤显著增加（在WIT为0、1、2、8、12、16和20小时时，分别为0.0%、0.0%、4.7%、2.4%、2.7%、31.4%和40.0%）（WIT在12至20小时之间，p < 0.001）。这些数据表明，随着WIT增加，细胞损伤呈进展性变化。收获相关WIT少于2小时的瓣膜几乎没有形态学损伤，暴露于12小时或更短热缺血时间的瓣膜中观察到的不可逆性细胞损伤极少。如果细胞活力对同种异体移植物的耐久性至关重要，那么与收获相关的热缺血可能需要限制在12小时以内。
