Thrombosis Program, Division of Hematology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada.
Thrombosis Program, Division of Hematology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada; Clinical Epidemiology Unit, Ottawa Hospital Research Institute, The Ottawa Hospital, Ottawa, Ontario, Canada.
Thromb Res. 2018 Feb;162:104-109. doi: 10.1016/j.thromres.2017.11.020. Epub 2017 Dec 8.
The optimal duration of oral anticoagulant therapy after a first, unprovoked venous thromboembolism is controversial due to tightly balanced risks and benefits of indefinite anticoagulation. Risk stratification tools may assist in decision making.
We sought to determine the relationship between residual pulmonary embolism assessed by baseline ventilation-perfusion scan after completion of 5-7months of oral anticoagulant therapy and the risk of recurrent venous thromboembolism in patients with the first episode of unprovoked pulmonary embolism.
We conducted a multicentre prospective cohort study of participants with a first, unprovoked venous thromboembolism enrolled after the completion of 5-7months of oral anticoagulation therapy. The participants completed a mean 18-month follow-up. Participants with pulmonary embolism had baseline ventilation-perfusion scan before discontinuation of oral anticoagulant therapy and the percentage of vascular obstruction on baseline ventilation-perfusion scan was determined. During follow-up after discontinuation of oral anticoagulant therapy, all episodes of suspected recurrent venous thromboembolism were independently adjudicated with reference to baseline imaging.
During follow-up, 24 of 239 (10.0%) participants with an index event of isolated pulmonary embolism or pulmonary embolism associated with deep vein thrombosis and central assessment of percentage of vascular obstruction on baseline ventilation-perfusion scan had confirmed recurrent venous thromboembolism. As compared to participants with no residual pulmonary embolism on baseline ventilation-perfusion scan, the hazard ratio for recurrent venous thromboembolism was 2.0 (95% CI 0.5-7.3) for participants with percentage of vascular obstruction of 0.1%-4.9%, 2.1 (95% CI 0.5-7.8) for participants with percentage vascular obstruction of 5.0%-9.9% and 5.3 (95% CI 1.8-15.4) for participants with percentage vascular obstruction greater than or equal to 10%.
Residual pulmonary embolism assessed by pulmonary vascular obstruction on baseline ventilation-perfusion performed after 5-7months of oral anticoagulant therapy for the first episode of unprovoked pulmonary embolism was associated with a statistically significant higher risk of subsequent recurrent venous thromboembolism. Percentage of pulmonary vascular obstruction assessment by ventilation-perfusion scans maybe a useful tool to help guide the duration of oral anticoagulant therapy after a first unprovoked pulmonary embolism.
Registered at www.clinicaltrials.gov identifier: NCT00261014.
由于长期抗凝治疗的风险和获益紧密平衡，首次无诱因静脉血栓栓塞后口服抗凝剂治疗的最佳持续时间存在争议。风险分层工具可能有助于决策。
我们旨在确定在完成 5-7 个月的口服抗凝治疗后，基线通气-灌注扫描评估的残留肺栓塞与首次无诱因肺栓塞患者复发性静脉血栓栓塞风险之间的关系。
我们对完成 5-7 个月口服抗凝治疗后的首次无诱因静脉血栓栓塞患者进行了多中心前瞻性队列研究。参与者平均随访 18 个月。在停止口服抗凝治疗前，有肺栓塞的参与者完成了基线通气-灌注扫描，并确定了基线通气-灌注扫描上的血管阻塞百分比。在停止口服抗凝治疗后的随访期间，所有疑似复发性静脉血栓栓塞的发作均根据基线影像学进行独立裁决。
在随访期间，239 名首发孤立性肺栓塞或肺栓塞伴深静脉血栓形成的患者中有 24 名（10.0%）和基线通气-灌注扫描上的中央评估血管阻塞百分比有确诊的复发性静脉血栓栓塞。与基线通气-灌注扫描上无残留肺栓塞的患者相比，血管阻塞百分比为 0.1%-4.9%的患者复发性静脉血栓栓塞的风险比为 2.0（95%CI 0.5-7.3），血管阻塞百分比为 5.0%-9.9%的患者为 2.1（95%CI 0.5-7.8），血管阻塞百分比大于或等于 10%的患者为 5.3（95%CI 1.8-15.4）。
在首次无诱因性肺栓塞接受 5-7 个月的口服抗凝治疗后，通过基线通气-灌注评估的残留肺栓塞与随后复发性静脉血栓栓塞的风险显著增加相关。通气-灌注扫描评估的肺血管阻塞百分比可能是指导首次无诱因性肺栓塞后口服抗凝治疗持续时间的有用工具。
在 www.clinicaltrials.gov 上注册，标识符：NCT00261014。
