Shrestha Biraj, Poudel Bidhya, Mene-Afejuku Tuoyo
Internal Medicine, Reading Hospital Tower Health System, Reading, USA.
Internal Medicine, AMITA Health Saint Francis Hospital, Evanston, USA.
Cureus. 2022 Apr 8;14(4):e23945. doi: 10.7759/cureus.23945. eCollection 2022 Apr.
Prosthetic valve thrombosis (PVT) is a frequent complication with a mechanical valve that presents with symptoms of heart failure or thromboembolic episodes. A 45-year-old lady with antiphospholipid syndrome (APS) complicated by a previous history of native mitral valve thrombus and mechanical mitral valve replacement maintained on warfarin presented with complaints of chest pain and shortness of breath (NYHA class 2). The initial lab showed a subtherapeutic international normalized ratio (INR) of 1.8. Transthoracic echo (TTE) showed severe mitral stenosis with a normal ejection fraction of 65%, elevated peak gradient of 34.5 mmHg, mean gradient of 23.7 mmHg, and pressure half time of 214 ms. Cine-fluoroscopic images revealed an immobile posterior mitral valve leaflet. She failed two trials of low-dose alteplase therapy during the hospitalization. Hence cardiac CT with contrast was done, which showed a small degree of pannus formation on the ventricular surface of the mitral valve ring and a small thrombus. Due to persistent immobility of the post mitral valve after two doses of alteplase and a cardiac CT scan concerning pannus formation, a multi-departmental decision was made to proceed with mechanical mitral valve replacement, following which she had a good recovery. Our case report depicts the importance of imaging study, like cardiac CT scan that can help distinguish thrombus (which has a lower Hounsfield unit, HU of <90) vs. pannus (higher HU of more than 145).
人工瓣膜血栓形成（PVT）是机械瓣膜常见的并发症，表现为心力衰竭或血栓栓塞发作的症状。一名45岁患有抗磷脂综合征（APS）的女性，既往有天然二尖瓣血栓病史且接受了机械二尖瓣置换术，一直服用华法林，现出现胸痛和呼吸急促（纽约心脏协会心功能分级为2级）的症状。初始实验室检查显示国际标准化比值（INR）低于治疗水平，为1.8。经胸超声心动图（TTE）显示严重二尖瓣狭窄，射血分数正常，为65%，峰值梯度升高至34.5 mmHg，平均梯度为23.7 mmHg，压力减半时间为214毫秒。荧光透视图像显示二尖瓣后叶活动度减低。住院期间，她两次低剂量阿替普酶治疗均失败。因此进行了心脏增强CT检查，结果显示二尖瓣环心室表面有轻度血管翳形成及小血栓。由于两剂阿替普酶治疗后二尖瓣后叶仍持续不能活动，且心脏CT扫描提示有血管翳形成，多科室决定进行机械二尖瓣置换术，术后她恢复良好。我们的病例报告描述了影像学检查的重要性，如心脏CT扫描有助于区分血栓（亨氏单位较低，<90 HU）和血管翳（较高，>145 HU）。
