BACKGROUND Limited data exist about the clinical presentation and outcomes of patients with inferior vena cava agenesis (IVCA) who develop deep vein thrombosis (DVT). METHODS We used the RIETE (Registro Informatizado Enfermedad Trombo Embólica) registry to compare clinical characteristics and outcomes of patients with lower limb DVT, according to the presence or absence of IVCA. Major outcomes included recurrent DVT, major bleeding and post-thrombotic syndrome (PTS). RESULTS Among 50,744 patients with lower-limb DVT recruited in October 2018, 31 (0.06%) had IVCA. On multivariable analysis, patients aged < 30 years (odds ratio [OR]: 17.9; 95%CI: 7.05-45.3), with unprovoked DVT (OR: 2.49; 95%CI: 1.17-5.29), proximal (OR: 2.81; 95%CI: 1.05-7.53) or bilateral DVT (OR: 11.5; 95%CI: 4.75-27.8) were at increased risk to have IVCA. Patients with DVT and IVCA had lower odds to present with coexisting PE (OR: 0.22; 95%CI: 0.07-0.73). During the first year of follow-up, the rates of DVT recurrences (hazard ratio [HR]: 1.30; 95%CI: 0.07-6.43), pulmonary embolism (HR: 2.30; 95%CI: 0.11-11.4) or major bleeding (HR: 1.32; 95%CI: 0.07-6.50) were not significantly different with those with versus those without IVCA. One year after the index DVT, IVCA patients had a higher rate of skin induration (OR: 3.70; 95%CI: 1.30-9.52), collateral vein circulation (OR: 3.57; 95%CI: 1.42-8.79) or venous ulcer (OR: 5.87; 95%CI: 1.36-1.87) in the lower limb than those without IVCA. CONCLUSIONS Certain clinical features such as unprovoked and bilateral proximal DVT in young patients should raise the suspicion for IVCA. Patients with IVCA had higher odds for symptoms of post-thrombotic syndrome.

中文翻译：

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RIETE登记册中下肢深静脉血栓形成患者的下腔静脉无创。什么时候以及为什么怀疑。

背景技术关于发展为深静脉血栓形成（DVT）的下腔静脉发育不全（IVCA）患者的临床表现和结局的数据有限。方法我们根据是否存在IVCA，使用RIETE（注册信息系统Enfermedad TromboEmbólica）注册中心来比较下肢DVT患者的临床特征和预后。主要结局包括复发性DVT，大出血和血栓形成后综合征（PTS）。结果2018年10月招募的50744例下肢DVT患者中，有31例（0.06％）患有IVCA。在多变量分析中，年龄小于30岁的患者（优势比[OR]：17.9； 95％CI：7.05-45.3），无缘无故DVT（OR：2.49； 95％CI：1.17-5.29），近端（OR：2.81； 95％CI：1.05-7.53）或双边DVT（OR：11.5; 95％CI：4.75-27.8）发生IVCA的风险增加。DVT和IVCA患者并存PE的几率较低（OR：0.22; 95％CI：0.07-0.73）。在随访的第一年，DVT复发率（危险比[HR]：1.30； 95％CI：0.07-6.43），肺栓塞（HR：2.30； 95％CI：0.11-11.4）或大出血（HR：1.32； 95％CI：0.07-6.50）与那些没有IVCA的患者相比没有显着差异。DVT指标一年后，IVCA患者的皮肤硬结率更高（OR：3.70； 95％CI：1.30-9.52），侧支静脉循环（OR：3.57； 95％CI：1.42-8.79）或静脉溃疡（ OR：5.87； 95％CI：1.36-1.87）。结论某些临床特征，如年轻患者的无端和双侧近端DVT，应引起对IVCA的怀疑。IVCA患者发生血栓后综合征的几率更高。