无支架带腱索支持生物心脏瓣膜的研究

STENTLESS CHORDALLY SUPPORTED BIOPROSTHETIC HEART VALVE:AN EXPERIMENTAL STUDY IN SHEEP

为研制无支架带腱索支持生物心脏瓣膜并对其血流动力学及抗钙化性能进行评价,试验选用年幼绵羊9只,新鲜牛心包经98％甘油鞣制后,缝制成21mm无支架生物瓣,在常温体外循环下行绵羊二尖瓣替换。术后不抗凝,2～8个月后择期行心导管,左室造影及病理检查。结果表明:全组无血栓、栓塞或感染。8例于术后168.4±55.3天,经血流动力学检测:平均跨瓣压差0.76±0.20kPa,有效瓣口面积1.9±0.75cm^2,心脏指数104.1±38.7ml/kg/min;瓣膜无关闭不全或轻度关闭不全者各3例,中度关闭不全者2例。瓣膜病理检查:仅2例有中度钙化,6例轻度钙化。电镜扫描示7例有内皮细胞覆盖生长。1例于术后220天死于心衰,为瓣膜交界处缝线松脱,产生关闭不全所致;其瓣膜表面光泽、柔软,无任何增厚或钙化灶。提示该无支架带腱索支持生物心脏瓣膜的血流动力学及抗钙化性能均满意。

Object:To research and fabricate a stentless chordally supported bioprosthetic heart valve, and evalute its hemodynamic functions and anticalcification properties in vivo. Method: Using fresh bovine pericardium after tanned with 98% glycerol, 21mm stentless tissue valves were fabricated for MVR under normothermic CPB in 9 juvenile sheep. Non of the 9 sheep received anticoagulation therapy. They were selectively sacrificed for heart cathterization, left ventricle angiography and pathological examination after a period of 2-8 months postoperatively. Results: All the sheep showed no thrombus, embolism or infection. 8 sheep received hemodynamic studies on 168. 4 ± 55. 3 days after MVR, which showed a mean gradient of 0. 76±0. 20kPa across the prosthesis, EGA 1.90 ± 0. 75cm2, CI 104. 1 ± 38. 7ml/kg/min;no regurgitation in 3 sheep, mild in 3, moderate in 2. Pathological studies showed only 2 sheep had moderate valvular calcification, 6 had mild calcification;SEM examinations showed 7 valves had host endothelial covering. 1 sheep died of heart failure 220 days postoperatively due to tore of the suture of the valvular commissure, but the valve was still smooth and soft, without any thickening or calcic focus. Conclusion: The hemodynamic functions and anticalcification properties of the stentless chordally supported bioprosthetic heart valve are satisfactory.