Investigation of non-physiological calcification in artificial organs after implantation ; OPN and macrophages

小口径血管假体用于儿童的愈合特点很少被观察到，因为取出标本很麻烦。对13例先天性心脏病患者采用改良的Blalock - Taussig分流术，采用小口径膨胀聚四氟乙烯（ePTFE）血管移植物和纤维移植物。在全矫正手术时，10例患者的10块ePTFE移植物和4例患者的6块织物移植物从远端肺吻合处取出，并进行评估。植入时间11个月~ 5年7个月（平均2年6个月）。切除时，患者平均年龄为4岁，所有移植物均通畅。显微镜下观察到3块ePTFE移植物壁钙化，免疫组织学观察到移植物壁内存在巨噬细胞。血栓形成、内膜增生和输卵管脱离是常见的。在织物移植物中，许多毛细血管渗透到间隙中，经常从移植物的周围侧到达管腔。这些结果表明，在紫绀儿童中，ePTFE移植物纤维内和周围的血管生成活跃，钙化加速。当使用高多孔纤维血管假体时，由血管生成引起的整个长度的完全内皮化可能在小孩中实现。

Healing characteristics of small-caliber vascular prostheses used in small children have rarely been observed because removing specimens are troublesome. Modified Blalock Taussig shunt procedures were performed using small caliber expanded polytetrafluoroethylene (ePTFE) vascular grafts and fabric grafts in 13 patients with congenital heart disease. At the time of total corrective procedures, a piece of 10 ePTFE grafts in 10 patients and six fabric grafts in four patients were removed from the distal pulmonary anastomosis, and evaluated. The implantation duration was from 11 months to 5 years and 7 months (mean, 2 years and 6 months). At removal, average patient age was 4 years and all grafts were patent. Microscopically, the wall of three ePTFE grafts were calcified, and macrophages were immunohistologically observed in the graft wall. Thrombus formation, intimal hyperplasia, and pannus detachment was common. In the fabric grafts, many capillaries infiltrated the interstices and often reached the lumen from the perigraft side. These results suggested that in cyanotic small children, angiogenesis in and around fabric grafts was active and calcification was accelerated in ePTFE grafts. Complete endothelialization throughout the length, caused by angiogenesis, might be possible in small children when highly porous fabric vascular prostheses are used.