肺小动脉原位血栓是慢性肺动脉高压重要的病理改变之一，诊断难度大且严重影响疾病的转归，目前多采用口服抗凝药物治疗但可能带来出血风险。若能无创性早期预警并早期干预治疗，针对原位血栓定点高浓度释药，定能显著提高溶栓效果。既往有研究表明靶向载药超声造影剂可以高效助溶体循环新鲜血栓，但对肺动脉原位血栓的溶栓未见报道。为此，本研究拟通过建立兔慢性肺动脉高压状态并肺小动脉原位血栓模型，超声心动图监测肺循环血流动力学参数变化及右心功能改变，结合血浆D-二聚体、纤维蛋白原等凝血/纤溶指标水平，右心导管肺动脉测压及肺组织病理学检查，探讨超声预警肺小动脉原位血栓的价值。进而，采用携RGDS载尿激酶靶向脂质体微泡在体溶栓，探讨靶向载药造影剂微泡助溶肺小动脉原位血栓的价值及可能机制，有望为临床早期干预治疗提供新的思路及依据，极大可能推进对肺动脉高压肺小动脉原位血栓的溶栓治疗。

Situ-thrombosis in pulmonary arterioles is one of prominent and common pathological findings in chronic pulmonary hypertension, which is hard to diagnose and a crucial factor for prognosis. At present, oral anticoagulants are frequently employed as therapeutic modality but with high bleeding risk. Given noninvasive early warning and early intervention in situ-thrombi in pulmonary arterioles by the thrombus-targeted and high-concentration drug release, the effect of the thrombolytic therapy would be significantly enhanced. Studies have showed that drug-loading targeted ultrasound contrast agent can effectively dissolve systemic fresh thrombus, yet there is no report on thrombolysis for situ-thrombosis in pulmonary arterioles. Therefore, this study is designed to explore the value of echocardigraphic parameters of pulmonary hemodynamics and right heart function in predicting situ thrombosis in pulmonary arterioles, by establishing rabbit model of pulmonary hypertension injected with Monocrotaline, combined with monitoring changes in plasma D-dimer and fibrinogen among blood coagulation-fibrinolysis system, pulmonary arterial pressure through right heart catheterization, and pathological tests on the lung tissue. And then, the availability of vivo thrombolysis of targeted liposome microbubbles which carry urokinase and RGDS is further investigated. This is expected to provide novel conception and evidence for early clinical treatment, and greatly promote the thrombolytic therapy of situ-thrombosis in pulmonary arterioles in pulmonary hypertension.