Tütün U, Ulus A T, Aksöyek A, Kaplan S, Ayaz S, Yilmaz S, Birincioglu L, Katircioglu S F
Department of Cardiovascular Surgery, Türkiye Yüksek Ihtisas Hospital, Ankara, Turkey.
Panminerva Med. 2002 Dec;44(4):359-63.
Mechanical prosthetic heart valve thrombosis is a serious complication with an incidence of 1-6%. The reduction in active vitamin-K dependent protein C and S levels caused by warfarin treatment also results in a prothrombotic state. This study was conducted to investigate the connection between protein C (PC), protein S (PS), antithrombin III (ATIII) deficiency and prosthetic mechanical valve thrombosis.
Twenty-nine of the 283 patients who underwent valve replacement with St. Jude medical prosthesis had mechanical valve thrombosis (group 2). The rest were considered as group 1. Twelve of the 29 patients (41.4%) had isolated aortic valve replacement, 12 had isolated mitral valve replacement (41.4%) and 5 patients had double valve replacement (17.2%). Most of the patients had rheumatic valve disease at their 1st operation. The mean time of occurrence for mechanical valve occlusion was 4.1+/-1.0 years following surgery.
The values of PC, PS and ATIII were obtained when the mechanical valves stuck or at routine follow-up. PC, PS and ATIII levels were significantly lower in the mechanical valve thrombosis group. PC levels were 75.4+/-37.6% and 49.9+/-32.2% in group 1 and 2, respectively (p=0.001). PC, PS and ATIII values were mostly lower in the 2nd group but this difference only became significant after at least 2 years of warfarin usage.
Natural anticoagulant levels can be low during the use of warfarin. In which case the dose can be increased in order to hold the international normalized ratio (INR) at 3-3.5. However, more frequent follow-up is required and patients should be investigated for hypercoagulation states or deficiency in anticoagulant proteins. Patients referred to hospital with any mechanical valve thrombosis or recurrent thromboembolism should be evaluated for hypercoagulant proteins.
机械人工心脏瓣膜血栓形成是一种严重并发症，发病率为1%-6%。华法林治疗导致活性维生素K依赖蛋白C和S水平降低，也会导致血栓前状态。本研究旨在调查蛋白C（PC）、蛋白S（PS）、抗凝血酶III（ATIII）缺乏与人工机械瓣膜血栓形成之间的联系。
283例接受圣犹达医疗假体瓣膜置换术的患者中，29例发生了机械瓣膜血栓形成（第2组）。其余患者被视为第1组。29例患者中，12例（41.4%）接受了单纯主动脉瓣置换术，12例（41.4%）接受了单纯二尖瓣置换术，5例（17.2%）接受了双瓣膜置换术。大多数患者首次手术时患有风湿性瓣膜病。机械瓣膜阻塞的平均发生时间为术后4.1±1.0年。
在机械瓣膜卡瓣时或常规随访时获得PC、PS和ATIII值。机械瓣膜血栓形成组的PC、PS和ATIII水平显著降低。第1组和第2组的PC水平分别为75.4±37.6%和49.9±32.2%（p=0.001）。第2组的PC、PS和ATIII值大多较低，但这种差异在使用华法林至少2年后才变得显著。
使用华法林期间，天然抗凝剂水平可能较低。在这种情况下，可以增加剂量以使国际标准化比值（INR）维持在3-3.5。然而，需要更频繁的随访，并且应该对患者进行高凝状态或抗凝蛋白缺乏的检查。因任何机械瓣膜血栓形成或复发性血栓栓塞入院的患者，应评估其抗凝蛋白情况。
