I NTRODUCTION

Retroperitoneal hematoma resulting from penetration of an inferior vena cava (IVC) filter is rare but fatal, especially in patients with double filters in the IVC. We describe a case of successful endovascular treatment of thrombosis in the IVC and follow-up of the subsequent retroperitoneal hematoma.

CASE REPORT

This case report was approved by our Institutional Review Board. A 55-year-old man with right lower extremity deep vein thrombosis (DVT) and inferior vena cava (IVC) thrombosis underwent IVC filter implantation and anticoagulant therapy in February 2003 at another hospital. The Vena Tech LP filter (B.Braun Medical S.A., Boulogne, France) can be seen in the IVC (Figure 1). The patient did not receive regular anticoagulant therapy after the filter implantation.Seven years later (April 2010), the patient was admitted to our hospital with complaints of bilateral lower limb swelling and pain of 1 week’s duration.Color Doppler ultrasound imaging indicated DVT in the left lower extremity and thrombosis in the IVC.

Figure 1. Abdominal X-ray showing permanent inferior vena cava filter.

Figure 2. Venography showing left lower extremity DVT and thrombosis in the IVC.

Venography showed left lower extremity DVT and a thrombus that had formed in the IVC filter (Figure 2).The original filter had lost the ability to prevent a pulmonary embolism (PE). To reduce the risk of thrombosis and pulmonary embolism and relieve clinical symptoms, a retrievable Günther Tulip filter(William Cook Europe, Bjaeverskov, Denmark) was placed intraoperatively in the appropriate suprarenal position and catheter-directed thrombolysis (CDT)and anticoagulant therapy was performed. Urokinase(500,000 U) was infused via a thrombolysis catheter(Angiodynamics, Uni Fuse, USA) over the course of 2 to 3 h, twice daily. Low-molecular-weight heparin calcium (0.4 mL) was injected subcutaneously twice daily.

Two days later, vena cava angiography showed that the thrombus in the IVC had partially dissolved.Lower limb swelling was alleviated. Laboratory data showed hemoglobin (HB) 135 g/L. However, due to the remaining thrombosis of the filter, the returned blood of IVC was limited, and further low-dose CDT treatment was required to be given. Six days after filter placement, the patient experienced sudden, persistent pain in the upper right abdomen, accompanied by pale skin and mucosa. The systolic blood pressure decreased to 90 mmHg. Laboratory data revealed HB 91 g/L, platelets 90 × 109/L, international normal ratio(INR) 1.2; abdominal computed tomography (CT)showed a large retroperitoneal hematoma along the lateral side of the IVC filter struts (Figure 3). The retroperitoneal hematoma may have been caused by the IVC as a result of the IVC wall injury by the filter.Removal of the IVC filter was planned to control the retroperitoneal hematoma. Vena cava angiography indicated that the residual intrafilter thrombus had completely dissolved (Figure 4). Lower limb swelling had totally resolved. However, attempted Günther Tulip filter retrieval through the right jugular approach were unsuccessful due to filter tilt. For this reason,thrombolysis was terminated, and symptomatic treatment, blood transfusion, and fluid infusion were administered.

尽管国际经济出现复苏，但全球性贸易仍然继续震荡，欧元区经济增速放缓，新兴市场经济动荡加剧，加上西方一些国家所设的各种经济壁垒，国际林产品市场竞争激烈，我国木材制品出口仍较困难。随着“一带一路”倡议的推进，深圳、成都、郑州等多个城市相继开通中欧班列，由于班列运输时间比海运缩短三分之二，价格是空运的四分之一，因而加速我国木材加工产品对“一带一路”沿线国家的出口速度，前3季度我国的刨花板和胶合板出口数量都实现了增长。纤维板的出口数量下降不少，但出口金额降幅收窄，木家具出口数量有增长，但出口金额基本与去年同期持平。

其中，Wij 是上层输入层单元i 和j 的权值，Oi 是上一层i 的输出，Bj 是j 的偏置，Oj 是j 的输出。

DISCUSSION

Figure 3. Retroperitoneal hematoma along with the struts of filter.

Figure 4. Unobstructed vena cava.

Vena cava filters are rarely complicated by retroperitoneal hematoma, especially when the retrievable Günther Tulip filter is used (8,9). The retrievable Günther Tulip filter has small barbed hooks at the caudal ends for fixation. This design of Tulip filters with less area that would come in contact with the vena cava can reduce the rate of vena cava perforation. Only one case of retrievable Günther Tulip filter placement complicated by sepsis and retroperitoneal hemorrhage has been reported, in 2005(10). This case was a woman with right femoral vein thrombosis. A retrievable Günther Tulip filter was inserted before knee replacement surgery. A large hematoma was formed, and the patient went into shock. The filter was removed and retroperitoneal hemorrhage was successfully controlled.

Retroperitoneal hematoma should be recognized as a rare but fatal complication after IVC filter placement,especially during anticoagulant and thrombolytic therapy (3). The struts of the vena cava filter may pierce the vessel wall (4). However, most patients are asymptomatic and rarely develop retroperitoneal hematoma (5). However, the occurrence of sudden abdominal pain, severe hypotension, or shock after insertion of a filter, is highly suggestive of a retroperitoneal hematoma (6,7).

Two days later, the patient‘s symptoms and hematologic profile had improved (HB 129 g/L, INR 1.2). Thereafter, the clinical course was favorable.Heparin was continued after discharge. Abdominal CT scans at 2, 3, and 6 months showed no evidence of recurrent thrombus, and there was a progressive decrease in size and absorption of the hematoma(Figures 5-8).

To our knowledge, this is the first case of double IVC filters being placed in one patient with long-term follow-up results. Placement of an IVC filter is an increasingly common request in patients with proximal lower extremity DVT (1). A number of permanent and retrievable filters are currently available (2). These filters are designed to prevent pulmonary embolism and reduce complications (2).However, there are no therapeutic modalities that can completely prevent all complications.

In the present case, a 55-year-old man with a permanent IVC filter developed thrombosis of the vena cava. The original filter had lost its ability to prevent PE, and on the contrary, it can be a potential risk factor for PE. On this occasion, a retrievable Tulip filter was placed in the appropriate suprarenal position.The benefit of a retrievable filter is that it can be removed when occlusion of the IVC has resolved or the risk of pulmonary embolism is over. A retrievable IVC filter can be left in place as a permanent filter if the risk of PE persists. We have previously used the Tulip filter to treat thrombosis in the IVC (11).Although thrombolytic therapy was effective in the present case, a retroperitoneal hematoma was presented on the sixth day after the filter implantation.It has been suggested that placement of a filter in the suprarenal position of the IVC may lead to penetration of the IVC wall as a result of respiratory motion and cardiac and aortic pulsation (10). Others have suggested that the risk of penetration is greater in a smaller IVC (12). Our patient may have had both of these risk factors.

Figure 5. Retroperitoneal hematoma absorbed gradually 2 months after discharge.

Figure 6. Further shrinkage of retroperitoneal hematoma 3 months after discharge.

Leonardi et al. reported the treatment of retroperitoneal hematoma by surgery. However, the mortality rate of surgery was high, and there was no long-term follow-up information (13). In this case, we found that the retroperitoneal hematoma was caused by the perforation of IVC filter other than anticoagulant or thrombolysis, because INR was in the normal range during thrombolytic treatment. In this way, the possibility of retroperitoneal hemorrhage induced by thrombolysis or anticoagulant was excluded. Although the filter retrieval attempts were unsuccessful due to filter tilt, the patient completely recovered by conservative treatment. Post-operation abdominal CT scans at 2, 3, and 6 months showed that there was no evidence of recurrent thrombus, and the hematoma was gradually absorbed.

采用上述方法对掘进工作面风筒布置方式及高压外喷雾降尘系统进行优化后，掘进工作面进风侧及回风侧测点处硫化氢浓度及净化效率检测结果见表1。可以看出，经过风筒位置优化后硫化氢治理效率在原有基础的平均值上提高6.3%，进风侧掘进机司机及其后5 m处硫化氢体积分数均降低到了3.6×10-6以下，在调整风筒位置情况下，对外喷雾布置调整后进风侧硫化氢体积分数降低到了1.8×10-6以下，回风侧体积分数降低到了6.1×10-6以下，对硫化氢的治理效率均值达到了95.6%。

Figure 7. Retroperitoneal hematoma disappear at 6 months.

Figure 8. Unobstructed vena cava and no recurrent thrombus.

REFERENCES

1. Wang SL, Lloyd AJ. Clinical review: inferior vena cava filters in the age of patient-centered outcomes. Ann Med 2013; 45:474-481.

2. Sing RF, Fischer PE. Inferior vena cava filters: indications and management. Curr Opin Cardiol 2013; 28:625-631.

3. Hanlon D. An evidence-based approach to managing the anticoagulated patient in the emergency department.Emerg Med Pract 2011; 13:1-19; quiz 19.

4. Piecuch, Wiewiora, Nowowiejska W, et al. Perforation of inferior vena cava during filter placement. Vasa 2011;40:157-162.

5. Ivascu FA, Janczyk RJ, Bair HA, et al. Spontaneous retroperitoneal hemorrhage. Am J Surg 2005;189:345-347.

6. González C, Penado S, Llata L, et al. The clinical spectrum of retroperitoneal hematoma in anticoagulated patients.Medicine 2003; 82:257-262.

7. Wang Y, Chang H, Wang W, et al. Delayed retroperitoneal arterial hemorrhage after inferior vena cava filter deployment. Medicine 2018; 97:e9618.

8. Neuerburg JM, Günther RW, Vorwerk D, et al. Results of a multicenter study of the retrievable Tulip vena cava filter: Early clinical experience. Cardiovasc Intervent Radiol 1997; 20:10-16.

9. Ray CE, Jr., Kaufman JA. Complications of inferior vena cava filters. Abdom Imaging 1996; 21:368-374.

10. Shimizu M, Tatsumi K, Matsukawa R, et al. Retrievable Günther Tulip Filter complicated by sepsis and retroperitoneal hemorrhage: Successful management by filter retrieval. Intern Med 2005; 44:593-597.

11. Xiao L, Shen J, Tong J-J, et al. Transcatheter thrombolytic therapy for symptomatic thrombo-occlusion of inferior vena cava filter. Exp Ther Med 2012;5:533-538.

12. Hoekstra A, Elstrodt JM, Nikkels PGJ, et al. Vessel wall reaction after vena cava filter placement. Cardiovasc Intervent Radiol 2002; 25:53-56.

13. Leonardi MJ. The rate of bleeding complications after pharmacologic deep venous thrombosis prophylaxis: A systematic review of 33 randomized controlled trials.Arch Surg 2006; 141:790-799.