目的：通过对先天性心脏病肺动脉高压(肺高压)患者血浆中血栓素B2/6-酮-前列环素F1a (TXB2/6-K-PGF1a)，Von Willebrand因子(VWF：Ag)，组织纤溶酶原激活物(tPA)测定及形态学改变(光、电镜改变)的研究，结合血液动力学，以探讨肺高压的发生机制。方法：分别采用放免分析、免疫扩散电泳法、发色底物分析法测定TXB2/6-K-PGF1a，VWF：Ag，tPA及对肺活检组织行光、电镜检查及VWF：Ag免疫过氧化酶染色。根据肺血管阻力(PVR)将病例分为3组(Ⅰ组PVR≤3.5 wood's单位；Ⅱ组PVR 3.5～5 wood's单位；Ⅲ组PVR>5 wood's)。结果：①肺高压组中TXB2/6-K-PGF1a，VWF：Ag明显上升，不同程度肺高压组中存在显著性差异(P<0.05)，且血浆中VWF：Ag与PVR，肺小动脉阻力(PAR)成直线正相关(r=0.89，0.82)，而tPA无明显改变。②随着肺高压的发展变化，肺血管内皮内的粗面内质网，微管微丝增生活跃，内膜下有大量弹力蛋白，且有纤维组织明显增生；VWF：Ag免疫过氧化酶染色随病理改变的严重而加深，同时肺血管病理改变的严重程度与临床生理检测到的肺高压的严重程度是一致的。结论：肺血管功能、结构改变可能是先天性心脏病肺高压发生的关键因素，本研究为药物干预性防治肺高压的发生提供了一定的理论依据。

OBJECTIVE: To investigate possible mechanisms resulting in pulmonary hypertension (PH) in patients with congenital heart disease (CHD). METHODS: Thromboxane B2/6keto Prostaglandin F1a (TXB2/6-K-PGF1a), Von Willebrand factor (VWF: Ag) and tissue plasminogen activator (tPA) plasma levels were measured. Changes in pulmonary vascular endothelial cells were assessed with light and electron microscopy. Ninety-nine children with CHD were divided into 3 groups according to pulmonary vascular resistance (PVR) (Group Ⅰ: PVR≤3.5 wood's unit; Group Ⅱ: PVR 3.5～5 wood's unit; Group Ⅲ: PVR>5 wood's unit). RESULTS: TXB2/6-K-PGF1a and VWF:Ag increased significantly in PH, and varied in different PH groups (P<0.05). There was a positive association between PVR and VWF: Ag (r=0.89, P<0.05) and between pulmonary artery resistance (PAR)and VWF: Ag (r=0.82, P<0.05). The levels of tPA in PH did not differ from normal. With the progressive changes on the light microscopy, the increases in the volume density of rough endoplasmic recticulum and microfilament bundles on the transmission electron microscopy were more significant and the immunostain for VWF: Ag was more intense. CONCLUSIONS: The functional and structural changes of endothelial cells are important in the pathogenesis of PH secondary to CHD. The experiments provide a theoretical basis for the modification of PH secondary to CHD with drug therapy.