Kearon C, Ginsberg J S, Anderson D R, Kovacs M J, Wells P, Julian J A, Mackinnon B, Demers C, Douketis J, Turpie A G, Van Nguyen P, Green D, Kassis J, Kahn S R, Solymoss S, Desjardins L, Geerts W, Johnston M, Weitz J I, Hirsh J, Gent M
McMaster University, Hamilton, Ontario, Canada.
J Thromb Haemost. 2004 May;2(5):743-9. doi: 10.1046/j.1538-7836.2004.00698.x.
The risk of recurrence is lower after treatment of an episode of venous thromboembolism associated with a transient risk factor, such as recent surgery, than after an episode associated with a permanent, or no, risk factor. Retrospective analyses suggest that 1 month of anticoagulation is adequate for patients whose venous thromboembolic event was provoked by a transient risk factor.
In this double-blind study, patients who had completed 1 month of anticoagulant therapy for a first episode of venous thromboembolism provoked by a transient risk factor were randomly assigned to continue warfarin or to placebo for an additional 2 months. Our goal was to determine if the duration of treatment could be reduced without increasing the rate of recurrent venous thromboembolism during 11 months of follow-up.
Of 84 patients assigned to placebo, five (6.0%) had recurrent venous thromboembolism, compared with three of 81 (3.7%) assigned to warfarin, resulting in an absolute risk difference of 2.3%[95% confidence interval (CI) - 5.2, 10.0]. The incidence of recurrent venous thromboembolism after discontinuation of warfarin was 6.8% per patient-year in those who received warfarin for 1 month and 3.2% per patient-year in those who received warfarin for 3 months (rate difference of 3.6% per patient-year; 95% CI - 3.8, 11.0). There were no major bleeds in either group.
Duration of anticoagulant therapy for venous thromboembolism provoked by a transient risk factor should not be reduced from 3 months to 1 month as this is likely to increase recurrent venous thromboembolism without achieving a clinically important decrease in bleeding.
与短暂性危险因素（如近期手术）相关的静脉血栓栓塞发作经治疗后的复发风险低于与永久性或无危险因素相关的发作。回顾性分析表明，对于静脉血栓栓塞事件由短暂性危险因素引发的患者，1个月的抗凝治疗就足够了。
在这项双盲研究中，因短暂性危险因素引发首次静脉血栓栓塞发作且已完成1个月抗凝治疗的患者被随机分配继续服用华法林或安慰剂，为期2个月。我们的目标是确定在11个月的随访期间，治疗时长能否在不增加静脉血栓栓塞复发率的情况下从3个月减至1个月。
在分配至安慰剂组的84例患者中，5例（6.0%）出现复发性静脉血栓栓塞，而分配至华法林组的81例中有3例（3.7%）出现，绝对风险差异为2.3%[95%置信区间（CI）-5.2，10.0]。停用华法林后，接受1个月华法林治疗的患者复发性静脉血栓栓塞发生率为每人年6.8%，接受3个月华法林治疗的患者为每人年3.2%（每人年发生率差异为3.6%；95%CI-3.8，11.0）。两组均未出现严重出血。
由短暂性危险因素引发的静脉血栓栓塞的抗凝治疗时长不应从3个月减至1个月，因为这可能会增加复发性静脉血栓栓塞，且无法在临床上显著降低出血风险。
