Langanki D, Ogle M F, Cameron J D, Lirtzman R A, Schroeder R F, Mirsch M W
St. Jude Medical, Inc., St. Paul, Minnesota 55117, USA.
J Heart Valve Dis. 1998 Nov;7(6):633-8.
The St. Jude Medical (SJM) Epic valve has been designed to diminish the risk of prosthetic valve endocarditis by the use of silver-coated polyester fabric, and to inhibit dystrophic calcification by the use of ethanol pretreatment.
A 20-week juvenile sheep mitral valve implant model was used to determine safety and efficacy of the device, as well as the rate of silver release and degree of dystrophic calcification. The SJM Epic valves were compared with SJM Biocor porcine valves (not ethanol-pretreated, not silver-modified polyester fabric) and Baxter Carpentier-EdwardsR standard valves.
Blood concentrations of silver reached a maximum of 40 p.p.b. within 10 days of SJM Epic valve implantation, and were well below toxic levels (300 p.p.b.). Blood silver concentrations returned to baseline within 30 days after surgery. Maximal silver accumulation occurred in the liver (16.75 mg/g dry weight); concentrations in the brain, spleen, kidney and lung were similar to those reported for other silver-modified prosthetic valves. No statistically significant difference was found in calcium content between SJM Epic and Biocor valves. The fibrous response to the sewing cuff was similar among the three valve types.
At all times tested, silver release from the SJM Epic valve led to blood concentrations well below toxic levels. Although calcification in the two SJM valve groups was extremely low, the 20-week sheep model may be insufficiently sensitive to detect differences in calcium accumulation in modern bioprosthetic valves.
圣犹达医疗公司（St. Jude Medical，SJM）的Epic瓣膜旨在通过使用涂银聚酯纤维织物降低人工瓣膜心内膜炎的风险，并通过乙醇预处理抑制营养不良性钙化。
采用为期20周的幼年绵羊二尖瓣植入模型来确定该装置的安全性和有效性，以及银释放速率和营养不良性钙化程度。将SJM Epic瓣膜与SJM Biocor猪瓣膜（未进行乙醇预处理，未采用银改性聚酯纤维织物）和百特Carpentier-EdwardsR标准瓣膜进行比较。
SJM Epic瓣膜植入后10天内，血液中银浓度最高达到40 ppb，远低于中毒水平（300 ppb）。术后30天内血银浓度恢复至基线水平。银的最大蓄积发生在肝脏（16.75 mg/g干重）；大脑、脾脏、肾脏和肺中的浓度与其他银改性人工瓣膜报道的浓度相似。SJM Epic瓣膜和Biocor瓣膜之间的钙含量未发现统计学上的显著差异。三种瓣膜类型对缝合袖口的纤维反应相似。
在所有测试时间点，SJM Epic瓣膜释放的银导致血液浓度远低于中毒水平。尽管两个SJM瓣膜组中的钙化程度极低，但20周的绵羊模型可能对检测现代生物人工瓣膜中钙蓄积的差异不够敏感。
