Schambeck C M, Schwender S, Haubitz I, Geisen U E, Grossmann R E, Keller F
Central Laboratory, University of Würzburg, Germany.
Thromb Haemost. 1997 Dec;78(6):1480-3.
The cumulative thrombotic risk of Factor V (FV) Leiden and oral contraceptives (OC) recommends screening for the mutation. Assuming that a family history of thrombosis increases the patient's likelihood of bearing FV Leiden, a selective rather than universal screening would be performed. We studied the utility of a family history of thrombosis for screening of FV Leiden before prescription of OC and, furthermore, the utility of screening even if oral contraception is favoured. 101 patients who had their first and single thromboembolic event while using OC were interviewed. 609 women without any history of thromboembolism recruited by gynecologists completed a standard questionnaire. 101 of these women, age-matched and currently using OC, were selected for a case-control study. Regarding patients with previous thromboembolism, a family history in a first-degree relative had a positive predictive value (PPV) of only 14% for FV Leiden. A PPV of 12% was calculated by investigating the 609 thrombosis-free women. Inherited FV Leiden (odds ratio = 4.9) and acquired risk factors (odds ratio = 10.1) were both found to be the most prominent, but independent additional risks. Nevertheless, FV Leiden carriers, both heterozygotes and homozygotes, did not suffer earlier from thromboembolism than patients without the mutation. In conclusion, family history is an unreliable criterion to detect FV Leiden carriers. Screening for factor V Leiden can be worthwhile even if the advantages of oral contraception are higher assessed than the thrombotic risk. Affected women knowing about their additional risk could contribute to the prevention of thrombosis in risk situations.
因子V（FV）Leiden突变和口服避孕药（OC）的累积血栓形成风险提示应对该突变进行筛查。假设血栓形成家族史会增加患者携带FV Leiden突变的可能性，那么应进行选择性而非普遍性筛查。我们研究了在开具OC处方前，利用血栓形成家族史筛查FV Leiden突变的效用，此外，还研究了即便倾向于使用口服避孕药时进行筛查的效用。对101名在使用OC期间首次发生且仅发生过一次血栓栓塞事件的患者进行了访谈。由妇科医生招募的609名无任何血栓栓塞病史的女性完成了一份标准问卷。从这些女性中选择了101名年龄匹配且目前正在使用OC的女性进行病例对照研究。对于既往有血栓栓塞史的患者，一级亲属的家族史对FV Leiden突变的阳性预测值（PPV）仅为14%。通过对609名无血栓形成的女性进行调查，计算出的PPV为12%。遗传性FV Leiden（优势比=4.9）和获得性危险因素（优势比=10.1）均被发现是最显著但独立的额外风险因素。然而，FV Leiden突变携带者，包括杂合子和纯合子，血栓栓塞的发病时间并不比未携带该突变的患者更早。总之，家族史是检测FV Leiden突变携带者的不可靠标准。即便对口服避孕药优势的评估高于血栓形成风险，筛查因子V Leiden突变仍可能是有价值的。知晓自身额外风险的受影响女性有助于在风险情况下预防血栓形成。
