| 在最近的一项Meta分析中，Yang Liu，Huan Lu（河南省肿瘤医院，郑州，中国）和他的同事发现没有足够的证据证明下腔静脉(IVC)过滤器可以降低肺栓塞 (PE) 相关死亡率和整体死亡率。 然而，他们确实发现IVC过滤器减少PE的发生，而不增加深静脉血栓栓塞(DVT)和大出血。 因此，他们得出结论：“IVC过滤器应该考虑在平衡有禁忌症的患者对PE的高风险抗凝治疗的好处和风险之后。”
Writing in the Journal of Vascular Surgery: Venous and Lymphatic Disorders, Liu, Lu, et al outline the scale of the issue at the core of their analysis: “Venous thromboembolism (VTE), which mainly presents as DVT and PE, is an important and potentially fatal disease with a high incidence and causes a huge burden.”
Considering treatment options, they write that, besides anticoagulation, the application of IVC filters is “commonly used” in patients with contraindications to anticoagulation therapy—for example, those who have been injured or who are at high risk of bleeding—or patients with a high risk of embolism occurrence. “However,” they write, “there is no clear consensus on the benefits and risks of IVCs from randomised controlled trials (RCTs)”.
Liu, Lu, and colleagues elaborate: “Systematic reviews have shown that IVC filters appear to reduce the incidence of subsequent PE, while appearing to increase the chance of DVT, and they have a limited effect on overall mortality. However, data in half of the included trials were not pooled into the effect size (odds ratio), which weakens the evidence of the conclusion.” Due to this lack of clarity on the subject, the researchers performed a systematic review and meta-analysis of RCTs with “more appropriate effect measures and more trials” in order to investigate the effect of IVC filters on PE-related mortality and complications.
The team searched PubMed and Cochrane libraries from inception to 31 October 2019 to identify RCTs for their meta-analysis. They detail that the primary outcome was mortality related to PE; secondary outcomes were overall mortality, occurrence of PE, DVT, and major bleeding.
Overall, the investigators included seven articles, comprising 1,274 patients, in their meta-analysis. They report that there was no significant difference in mortality related to PE between the IVC filter groups and the control group within three months (risk difference, -0.01; 95% confidence interval [CI], -0.03–0; p=0.11) and during the whole follow-up time with low heterogeneity (I2=0%).
However, they relay that the rates of new occurrence of PE within three months and during the whole follow-up period were lower in the IVC filter group than those in the control group (0.81% vs. 5.98%; risk ratio, 0.17; 95% CI, 0.04–0.65; p=0.01; 3.2% vs. 7.79%; risk ratio, 0.42; 95% CI, 0.25–0.71; p=0.0001, respectively).
Finally, Liu, Lu, et al communicate that there were no significant differences in the rates of new occurrence of DVT, major bleeding, and mortality rates during the whole follow-up period between the groups (p>0.05).
The authors acknowledge some limitations of the present study. They recognise, for example, that patients who were recruited in the included trials were “not completely consistent” regarding disease conditions and that performing subgroup analyses was limited because of the paucity of trials. Finally, they state that performance bias was a high risk, which was attributed to the “dramatic difference” in therapy between the two groups. “This made participants and personnel blinding from the intervention strategy impossible, and might have affected the outcomes to a certain extent,” they remark.
Looking forward, Liu, Lu, and colleagues suggest that large RCTs are required “to provide more robust evidence”.
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