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BACKGROUND: An inferior vena cava filter is an effective tool to prevent fatal pulmonary embolism. The existing filters have some shortcomings that limit their clinical application. OBJECTIVE: To evaluate the feasibility and capture efficiency of a new self-convertible inferior vena cava filter (SCF) in vivo. METHODS: L-lactide and ε-caprolactone were fused and polymerized to act as a degradable deformable switch of the filter. Medical stainless steel wire as the metal structure of the filter was combined with the degradable deformable switch to make the SCF. Eight SCFs were implanted into the inferior vena cava of eight adult Beagle dogs. The inferior vena cava angiography was performed to evaluate the release process, morphology and location of the filter. Venous angiography was performed 2 weeks later to evaluate the morphology and location of the filter and inferior vena cava patency. Detection of pulmonary embolism or other complications was performed at autopsy. RESULTS AND CONCLUSION: Eight SCFs were successfully implanted and positioned accurately with no tilt, and they were converted successfully at 2 weeks after the implantation, as assessed by the venous angiography. One of the eight SCFs migrated to the orifice of the right atrium, and caused asymptomatic inferior vena cava obstruction. The remaining SCFs were normally positioned with no tilt and local lesion or obstruction after deformation. No marked filling defect in the trunk of the pulmonary artery was shown by the pulmonary artery angiography. The autopsy report revealed that the filter arm had been endothelialized, and the inferior vena cava that was in contact with the filter arm had no obvious stenosis. Mild intimal hyperplasia, less than 1 mm in thickness, was found in the bottom of the filter arm, but it did not cause a stenosis in the lumen. No vena cava perforation, retroperitoneal hemorrhage, and injury of the surrounding viscera were found. Overall, the design of the SCF is feasible. [ABSTRACT FROM AUTHOR]

BACKGROUND: Inferior vena cava filter is an effective way to prevent fatal pulmonary embolism. The existing filters have some shortcomings that limit the clinical application. OBJECTIVE: To evaluate the feasibility and capture efficiency of a new self-convertible inferior vena cava filter (SCF) in vitro. METHODS: The biodegradable switch was constructed of a copolymer of ε-caprolactone and L-lactide (75%/25%, PCLA75). The biodegradable switch bound together with the apices of the convertible struts to make the self-convertible filter. The deformability and capture efficiency of the filter were tested in an in-vitro flow model with three different diameters (22, 25, 28 mm). A total of 15 filters were implanted both in the vertical and horizontal positions, and the tilt angle of the filter was tested after release. To accelerate switch degradation, a lipase perfusate was injected into the flow model and refreshed every 8 hours until conversion. RESULTS AND CONCLUSION: (1) All the filters were successfully implanted without tilting, both in the vertical and horizontal positions in the three different diameter models. (2) All the 15 SCFs were converted successfully without tilting, structural damage, and displacement. (3) The capture efficiency of the SCF had significant difference between the different diameter of the models, the size of the embolus and the position of the two models (P < 0.001). The mean capture efficiency was 82.5%, and the capture efficiency exhibited a downward trend with the increase of pipe diameter, the decrease of emboli size, and the position of pipeline changing from vertical to horizontal. All these results show that the SCF is feasible and highly efficient. [ABSTRACT FROM AUTHOR]

Objective: To examine the application effect of the modified wire-loop snare technique in retrieving severely tilted inferior vena cava filters (IVCF). Methods: The clinical data of 18 patients (12 males and 6 females, aged (62.1±13.1) years (range: 29 to 78 years)) who underwent the modified wire-loop snare technique to retrieve IVCF at the Affiliated Hospital of Qingdao University, Qingdao Eighth People's Hospital, and Jimo District Hospital of Traditional Chinese Medicine from November 2017 to April 2022 were retrospectively analyzed. The applied filters included drum-type filters (OptEase in 7 cases, Aegisy in 2 cases) and conical filters (Celect in 6 cases and Denali in 3 cases). Preoperative CT angiography and intraoperative digital subtraction angiography showed that the filter was severely tilted and the hook was covered by hyperplastic intima of the vena cave vein. A modified wire-loop snare technique was used to retrieve drum-type filters and conical filters via femoral and jugular vein approaches, respectively. After successful puncture, the long sheath was placed, the 4 F (1 F≈0.33 mm) vertebral catheter and a snare were inserted through the long sheath, and the 5 F pigtail catheter was inserted simultaneously to guide a 0.035 inch soft guide-wire (260 cm in length) to pass through the top of the filter and turning back. The tip of the soft guide-wire was snared by the vertebral catheter and pulled out of the sheath. The 4 F vertebral catheter was inserted following the tip of the guide-wire to form a wire-loop using the vertebral catheter and the pigtail catheter. After fixing the tip and tail of the soft guide-wire in vitro , the long sheath was pushed forward to cut the hyperplastic intima and the hook was pulled away from the vena cava wall to retrieve the filter under the support of two catheters. Results: The filters were successfully retrieved in 17 cases, the operation time was (25.5±8.7) minutes (range: 15 to 45 minutes), no complication occured. The hook of one filter (Celect) penetrated out of the vena vava wall and the wire-loop could not pull the hook back into the vena cava. Then the filter was removed by laparotomy. Conclusion: The modified wire-loop snare technique could retrieve the severely tilted retrivable drum-type filters and conical filters, even when serve adhesion exists between the filter and the vena cava wall.

The dynamic analysis of the implantation process of a new vena cava filter was carried out by finite element analysis method to reveal the influence of the angle, length, width and thickness of the filter rod on its mechanical properties and the inner wall of the blood vessel. The results showed that the high-stress and high-strain areas of the filter were mainly concentrated in the connection between the filter rod and the filter wire. With the increase of the angle of the filter rod, the maximum equivalent stress and the maximum elastic strain on the filter wall decreased, while the maximum equivalent stress on the vascular wall increased. With the increase of the length of the filter rod, the maximum equivalent stress and strain peak of the filter wall increased, but the maximum equivalent stress of the vessel wall decreased. With the increase of the width and thickness of the filter rod, the maximum equivalent stress of the filter wall, the maximum elastic strain and the maximum equivalent stress of the vessel wall all showed an upward trend. The static safety factor of all filter models was greater than 1, and the structure after implantation was safe and reliable. The results of this study are expected to provide a theoretical basis for the structural optimization and deformation mechanism of the new type vena cava filter.

Objective: To assess the technical success rate, stent patency, clinical efficacy and complications of stent placement for filter-related chronic occlusion of the inferior vena cava. Methods: A retrospective analysis was carried out for 12 patients with filter-related chronic occlusion of the inferior vena cava associated with severe post-thrombotic syndrome, who underwent stent placement after ineffective conservative therapy at Nanjing First Hospital from March 2016 to December 2018,9 males and 3 females, aged from 48 to 77 years, mean age 60 years, six had bilateral lower extremity symptoms and six had unilateral lower extremity symptoms.Technical success rate, stent patency, clinical efficacy and complications of stent placement were recorded. Clinical success was defined as relief of symptoms and a decrease in clinical, etiology, anatomy, and pathophysiology (CEAP) score for at least grade 1. Results: Stent placement in the unilateral or bilateral iliocaval occlusion was successful in 11 patients. The cause of technical failure in the single patient with failed stent placement was an inability to cross the occluded left iliacvein and the patient was treated with stent placement in the right iliocaval vein.There were 7 patients with inferior vena cava and unilateral iliocaval stent placement; 5 patients with inferior vena cava and bilateral iliocaval stent placement. Acute stent thrombosis occlusion occurred in 1 case after the operation, the blood flow recanalized after catheter-directed thrombolysis and re-stenting. All patients were followed up for 6 to 24 months, with an average of (13±6) months. During the follow-up period, CTV or venography of lower limbs showed that the blood flow in the stent was unobstructed. At the last follow-up, 12 patients were evaluated as clinically effective. Three patients had transient treatment of lateral lumbar pain during operation, which alleviated by themselves.No significant abdominal pain, severe hemorrhage, symptomatic pulmonary embolism and other complications related to treatment occurred in all patients during perioperative period and follow-up. Conclusion: Stent placement is safe and feasible in the treatment of filter-related chronic occlusion of the inferior vena cava, which can alleviate the clinical symptoms of severe post-thrombotic syndrome.

Vena cava filter is a filter device designed to prevent pulmonary embolism caused by thrombus detached from lower limbs and pelvis. A new retrievable vena cava filter was designed in this study. To evaluate hemodynamic performance and thrombus capture efficiency after transplanting vena cava filter, numerical simulation of computational fluid dynamics was used to simulate hemodynamics and compare it with the commercialized Denali and Aegisy filters, and in vitro experimental test was performed to compare the thrombus capture effect. In this paper, the two-phase flow model of computational fluid dynamics software was used to analyze the outlet blood flow velocity, inlet-outlet pressure difference, wall shear stress on the wall of the filter, the area ratio of the high and low wall shear stress area and thrombus capture efficiency when the thrombus diameter was 5 mm, 10 mm, 15 mm and thrombus content was 10%, 20%, 30%, respectively. Meanwhile, the thrombus capture effects of the above three filters were also compared and evaluated by in vitro experimental data. The results showed that the Denali filter has minimal interference to blood flow after implantation, but has the worst capture effect on 5 mm small diameter thrombus; the Aegisy filter has the best effect on the trapping of thrombus with different diameters and concentrations, but the low wall shear stress area ratio is the largest; the new filter designed in this study has a good filtering and capture efficiency on small-diameter thrombus, and the area ratio of low wall shear stress which is prone to thrombosis is small. The low wall shear stress area of the Denali and Aegisy filters is relatively large, and the risk of thrombosis is high. Based on the above results, it is expected that the new vena cava filter designed in this paper can provide a reference for the design and clinical selection of new filters.

Objective: To analyze the curative effect of AngioJet mechanical thrombus aspiration combined with catheter directed thrombolysis (CDT) on acute lower extremity deep vein thrombosis (LEDVT). Methods: The clinical data of 20 cases of acute LEDVT treated by AngioJet combined with CDT were analyzed. The inferior vena cava filter was implanted preoperatively, and then the thrombolysis was performed by using AngioJet. The thrombolytic catheter was placed for CDT treatment, and the thrombolysis was evaluated by review angiography. Results: All cases were successfully punctured and catheterized. The suction time was (235±75) seconds. The usage of urokinase was (180±90)*10(4) U. The differences before and after thrombolysis of ipsilateral and contralateral thigh circumference were (8.3±1.5) cm and (2.5±1.0) cm, respectively. The differences before and after thrombolysis of the ipsilateral and contralateral calf circumference were (2.4±1.0)cm and (1.5±0.7) cm, respectively. All of which had statistical significant ( P <0.01). Conclusion: AngioJet mechanical thrombus aspiration system is a novel and safe method for the treatment of acute LEDVT. When used in conjunction with CDT, its advantages was more significant.

Vena cava filter (VCF)has been increasingly applied in clinical to efficiently prevent the pulmonary embolism (PE) with the rapid development of VCF. This article summarized the development of VCF, analyzed the relationship between structure and function, described the clinical behaviour of VCF, and final y forecasted the development trend of VCF products.

Objective: To evaluate the safety and efficacy of suprarenal inferior vena cava (IVC) filter implantation in patients with venous thromboembolism (VTE)., Methods: Between May 2006 and December 2014, 28 patients with VTE underwent suprarenal IVC filter implantation, anticoagulant treatment and/or catheter-directed thrombolysis at the affiliated hospital of Xuzhou medical college. Follow up examination with color Doppler ultrasound was taken after treatment to eassess the patency of IVC., Results: One filter was successfully implanted in suprarenal IVC in each patient intraoperatively. The filter was retrieved in 26 patients after indwelling of 5 to 17 (mean 11 ± 3) days. The filter was permanently indwelled in 2 patients. There were no complications of filter tilt and migration in all cases. Twenty eight patients were followed up for 2 to 104 (mean 34 ± 34) months. None of the 2 patients whose filters were permanently indwelled presented complications of recurrent pulmonary embolism and IVC occlusion due to the filter. Among 26 patients whose filters were retrieved, the IVC was patent., Conclusion: Suprarenal IVC filter placement is a safe and effective method in the treatment of VTE.

Objective: To evaluate the efficacy and safety of catheter-directed thrombolysis (CDT) in treating with inferior vena cava (IVC) thrombosis after filter implantation., Methods: A retrospective analysis of 13 patients with IVC thrombosis after filter implantation was conducted at our institution from June 2009 to June 2012. A total of 26 lower extremities were involved.IVC filters were implanted via right internal jugular vein. Then CDT was performed through small saphenous vein, popliteal vein or femoral vein. The dosage of urokinase was 0.6-1 million/day. The occlusive segment in IVC was managed with percutaneous transluminal angioplasty (PTA) and stenting., Results: The obstructed IVC was re-opened after CDT in 11 cases. The average CDT time was 8.3 (7-13) days. PTA (n = 2) and stenting (n = 1) were performed. A total of 4 retrievable filters were planted and retrieved later successfully.No severe complications occurred. During the follow-ups, no clinically detetable sighs of pulmonary embolism were observed., Conclusion: CDT is effective, safe and feasible in the treatment of IVC thrombosis after filter implantation.

Objective: To evaluate the application of inferior vena cava filter (IVCF) in prevention of peri-operative pulmonary embolism (PE) in lower limb bone fracture patients with deep venous thrombosis (DVT)., Methods: From January 2003 to December 2012, 2 248 cases of lower limb and pelvic fractures with DVT were retrospectively analyzed. Before the procedure of IVCF implantation began, January 2003 to December 2007, there were 1 052 cases of acute trauma patients with DVT were classified as the group of early none-IVCF. The IVCF implantation was began since January 2008. From that time to December 2012, 712 cases of bone fractures with DVT received filter implantation, which were classified as IVCF group. The other 484 patients who had not undergone filter deployment were divided as group of late none-IVCF. The baseline conditions of the three groups were significantly different in addition to the ages between group of early none-IVCF and IVCF group. The incidences of PE and mortality of PE in each group were recorded and analyzed by χ(2) test., Results: There were totally 31 cases of symptomatic PE, among which 12 cases died. Totally 712 filters were deployed successfully without any major complications. The incidences of symptomatic PE were 0.14% (1/712), 2.19% (23/1 052) and 1.45% (7/484) in IVCF group, group of early none-IVCF and group of late none-IVCF, respectively. The mortality of PE were 0 (0/712), 0.86% (9/1 052) and 0.62% (3/484) in these groups. The incidence of symptomatic PE in IVCF group was significantly different from that in the group of early and late none-IVCF (χ(2) = 11.762, P = 0.001; χ(2) = 7.395, P = 0.007, respectively). The mortality of IVCF group was also significantly lower compared with the other two groups (χ(2) = 6.122, P = 0.013; χ(2) = 4.424, P = 0.035, respectively)., Conclusion: IVCF implantation effectively prevents symptomatic and fatal PE of patients of lower limb and pelvic fractures with DVT in the peri-operative period.

Objective: To explore the characteristic, diagnosis and treatment of deep venous thromboembolism (DVT) patients with congenital double inferior vena cava., Methods: Retrospective analyses were conducted for the indications, filter types and efficacies of vena cava filter insertion in 7 hospitalized DVT patients with congenital double inferior vena at our hospital from 2006 to 2012., Results: All of them had definite indications for vena cava filter insertion. Temporary and permanent vena caval filters were implanted in one subject while retrievable vena caval filters in another five subjects. One retrievable filter was replaced by a permanent filter due to excessive thrombus entrapped in filter. Other temporary or retrievable filters were extracted successfully. All subjects were prescribed postoperatively with oral anticoagulants. The follow-up period was 1-72 months. No recurrent DVT or pulmonary embolism occurred., Conclusion: The complications of double inferior vena cava in DVT subjects are often misdiagnosed due to its low incidence rate and a lack of clinical manifestations. Fatal pulmonary embolism after implantation may be due to an inappropriate location of filter implant. If implanted in a proper position, satisfactory outcomes ensue.

Objective: To explore the clinical profiles of patients with lower extremity deep venous thrombosis (DVT) complicated with inferior vena cava (IVC) thrombus and summarize their clinical diagnostic and therapeutic experiences., Methods: The clinical characteristics, diagnosis and treatment of 20 hospitalized patients with DVT complicated with inferior vena cava thrombus were analyzed retrospectively., Results: All of them were of proximal DVT. There were phlegmasia cerulea dolens (n = 3), pulmonary embolism (n = 3) and completely occlusion of IVC (n = 5). Clinical manifestations were severe. Retrievable inferior vena cava filter (IVCF) was implanted for 17 cases. Catheter-directed thrombolysis (CDT) through ipsilateral popliteal vein was applied for 7 cases and systemic thrombolysis therapy for 8 cases. The effective rate of thrombolysis for fresh IVC thrombus was 100%. Among 5 cases with Cockett Syndrome, 3 cases underwent balloon dilatation angioplasty and endovascular stenting of iliac vein. And 17 IVCFs were retrieved successfully within 3 weeks. IVC thrombus disappeared completely in 15 cases., Conclusion: Systemic or local thrombolysis with protective IVCF is a safe and effective therapy for nonocclusive IVC thrombus in DVT. And CDT is recommended for symptomatic occlusive IVC thrombus.

Objective: To explore the efficacy and feasibility of color Doppler flow imaging (CDFI)-guided inferior vena caval filter (IVCF) insertion through the right internal jugular vein for prevention of pulmonary embolism in patients with deep venous thrombosis (DVT)., Methods: Thirty-eight patients with lower extremity DVT confirmed by clinical and CDFI examinations underwent IVCF insertion through the right internal jugular vein under guidance of CDFI for prevention of pulmonary embolism. The shape and position of IVCF were monitored by CDFI regularly. After 32 to 45 days, the retrievable filters were removed under CDFI guidance via the right internal jugular vein. All patients were followed up to monitor the occurrence of filter complications and pulmonary embolism PE., Results: Preoperative CDFI clearly displayed the locations of the right internal jugular vein, inferior vena caval (IVC), bifurcation of the common iliac vein, and the bilateral renal veins in all the 38 patients. All the veins were free of anatomical variations or embolism. Under CDFI guidance, 23 retrievable IVCF and 15 permanent IVCF were placed without technical difficulty via the right internal jugular vein. Follow-up examination with CDFI and abdominal plain X-ray film showed that all the filters were placed in right positions with complete opening. The 23 retrievable filters were retrieved via the right internal jugular vein after 32-45 days. IVCF captured venous emboli in 14 cases (36.5%). None of the patients had filter displacement, tilting, or fracture or showed IVC perforation or the occurrence of pulmonary embolism., Conclusion: CDFI-guided IVCF insertion via the jugular vein is safe and feasible. Compared with X-ray guidance, CDFI guidance is convenient and substantially reduces the procedural cost and avoids the risk of radiation exposure.

Objectives: To evaluate the application of inferior vena cava filter (IVCF) in prevention of peri-operative pulmonary embolism in patients with bone fracture combined with deep venous thrombosis (DVT)., Methods: From July 2007 to April 2011, 572 cases of bone fractures consequent with DVT that confirmed by Duplex were deployed IVCF to avoid fatal pulmonary embolism in the para-operative period. There were 318 male and 254 female patients with a mean age of (51±23) years (ranging from 16 to 94 years)., Results: All the operations of deployment of the IVCFs were successfully. There were 174 permanent and 399 temporary IVCFs deployed. In all 399 temporary filters, 389 filters were taken out successfully. The mean station time in the IVC of the temporary filters was 22.8 days (7 to 60 days), among which, 118 were found of captured thrombus. After the follow-up of mean 16 months (3 to 40 months) of 566 patients, no pulmonary embolism occurred, but symptomatic DVT were revealed in 15 patients, and the conditions were improved after anticoagulation treatment. No serious complication of post thrombotic syndrome occurred., Conclusion: IVCF deployment can prevent the trauma patients with deep vein thrombosis of fatal pulmonary embolism in the peri-operative period, which may also offer a safe condition to the orthopedic operations.

Objective: To investigate the indications, safety and efficacy of catheter directed thrombolysis for early left lower extremity deep venous thrombosis (DVT) without vena cava filters protection., Methods: Clinical data of 54 cases of early left lower extremity DVT received catheter directed thrombolysis without vena cava filters from July 2008 to June 2010 were retrospectively analyzed. The thrombosis was entire without free floating clots and no thrombosis in vena cava detected with ultrasound scan. Twenty-five patients were male and 29 were female with the average age of 52.8 years. Fifty-one of which were iliofemoral and popliteal, the other 3 were iliofemoral. The course were ≤ 7 d in 45 cases and these were 8 to 30 d in 9 cases. Urokinase of 300 000 U was infused through catheters per 2 h twice a day. Meanwhile 4000 U of low weight heparin was administered subcutaneously per 12 h, or heparin infusion at dosage of 18 U×kg(-1)×h(-1)., Results: The procedure technically succeeded in all patients. In total cases venous score decreased to 4.6 ± 2.1 post 6 to 10 d of thrombolysis from 10.8 ± 1.0 with thrombolysis rate of 58% ± 18% which was not significantly different between groups of ≤ 7 d and 8 to 30 d (t = 1.02, P = 0.34). On 14(th) day, 11 patients (20.4%) completely recovered, 35 cases (64.8%) experienced large improvement, 8 patients (14.8%) had mild improvement and nobody was failed, resulting in total efficacy of 100%. No patient developed clinical symptomatic pulmonary embolism. SpO2 did not alter markedly post thrombolysis [(91.0 ± 2.6)% vs. (90.8 ± 2.4)%, t = 2.03, P = 0.05]. No patients suffered from cerebral hemorrhage and haemoturia, and catheter induced inflammation occurred in 4 cases (7.41%). There was mild bleeding in puncture sites in 11 patients (20.4%) during the course. There were 36 patients (66.7%) had been followed up with the time of 6 to 21 months. In which 31 cases had no lower extremity edema or had mild edema after activities. Two patients developed serious edema after activities for deep venous insufficiency. Three cases combined with malignant tumor or renal failure recurred., Conclusions: For early left extremity DVT which is entire without free floating clots and no thrombosis in vena cava, catheter directed thrombolysis without filter protection maybe administered with safety, efficiency and lower expense.

Objective: To evaluate the clinical features, diagnostic methods and treatment of venous thromboembolic disease (VTE) during pregnancy., Methods: From June 2006 to June 2011, a total of 20 pregnant women were diagnosed VTE at the Department of Obstetrics and Gynaecology, Qilu Hospital of Shandong University. Clinical data of these patients were analyzed retrospectively., Results: (1) Characteristics of patients:the symptoms of all the 20 patients commenced in pregnancy. Of these, 6(30%) happened in the first trimester, 7 (35%) in the second trimester, and 7 (35%) in the third trimester. Twelve (60%) patients went to hospital in one week after they had symptoms, while 8 (40%) went to hospital after one week. (2) Clinical manifestation: 18 patients were diagnosed deep venous thrombosis (DVT), one was diagnosed pulmonary embolism (PE). One patient was diagnosed DVT and PE simultaneously. Among the 19 DVT patients, 16 (16/19)were on the left side, 3(3/19)were on the other. They all came with sudden swelling and pain of the affected lower extremity. In 17 (17/19) patients, the circumference differences between two legs were beyond (4.0 ± 0.5) cm. In all the 20 patients, 12(60%) had elevated plasma level of D-dimmer. The diagnosis of DVT was made mainly by a Doppler ultrasound. Among the 19 DVT events, 7 (7/19) were proximal DVT, 2 (2/19) were distal, and 10(10/19) were mixed type. (3) Anticoagulant therapy: patients with VTE during pregnancy were treated with low molecular weight heparin (LMWH) (enoxaparin, once 1 mg/kg subcutaneous, twice a day). After delivery, patients were treated with subcutaneous LMWH and warfarin simultaneously for at least 5 days, until the prothrombin time-international normalized ratio (PT-INR) was > 2.0 for 24 hours. (4) Thrombolytic therapy: for most patients with VTE, we are against the routine use of thrombolytic therapy, especially before delivery. For patients with acute massive PE, urokinase of 600 000 units intravenously daily was recommended for 3 days. For those patients with DVT whose standard anticoagulation therapy was < 30 days, an inferior vena cava filter (IVCF) placement was recommended before delivery or abortion. If it was ≥ 30 days, IVCF was not recommended as a routine, and anticoagulant therapy was used 24 hours after delivery. If there was no recurrent DVT or PE, IVCF was retrieved routinely in 12 days. (5) OUTCOME: among patients treated with LMWH (95%, 19/20). Three received IVCF placement, which was retrieved successfully in 12 days, with no interventional complication. All patients recovered well after 2 weeks, and the circumference differences between two legs were within (2.0 ± 0.3) cm. Of the 18 patients maintained to the third trimester, 17 received anticoagulant therapy, and no abnormal findings were found during antenatal examination. Ten patients received cesarean section (50%, 10/20), while 8 had vaginal delivery (40%, 8/20). Neither neonatal asphyxia nor malformation was observed. The patients were followed-up for 1 - 24 months, no venous thrombus extension was found in 17 cases by Doppler ultrasound, thrombus disappeared in 2 cases of distal DVT after 4 weeks and 8 weeks respectively. By echocardiography, the pulmonary arterial pressure of the 2 patients with PE was found normal 3 months after hospital discharge. There was no maternal death during the study, no recurrent PE or bleeding occured., Conclusions: LMWH is safe and effective for VTE during pregnancy. Routine use of thrombolytic therapy is not recommended. VTE in pregnancy is not the absolute indication of termination of pregnancy. The indication of an IVCF placement should be stricter, and a retrievable suprarenal IVCF is recommended under certain circumstances.

Objective: To summarize the clinical experiences of treating deep venous thrombosis (DVT) with retrievable vena cava filter., Methods: A total of 180 patients with DVT in unilateral lower extremity were recruited. There were 82 males and 98 females with an average age of 46 years old. After the diagnosis of vascular color Doppler ultrasound, retrievable vena cava filter was implanted through contralateral femoral vein. Simultaneously another 114 patients underwent femoral vein embolectomy. All cases received the post-operative therapies of anticoagulation, thrombolysis and vasodilation., Results: The implantation of retrievable vena cava filter was successful in all cases. Among 142 cases of attempted extraction, 116 filters were extracted successfully at Days 12 - 24. The success rate was 81.69%. Filters captured thrombosis in 34 cases (29.31%)., Conclusion: As a safe and efficacious method, the implantation of retrievable vena cava filter prevents the occurrence of pulmonary embolism in the patients with DVT in unilateral lower extremity. Its timely extraction may avoid the long-term complications.

Objective: To evaluate the clinical outcome of surgical venous thrombectomy and simultaneous stenting in patients with acute, symptomatic iliofemoral deep venous thrombosis (DVT)., Methods: From October 2008 to December 2010, a total of 15 patients with acute symptomatic DVT underwent combined surgical venous thrombectomy and endovascular stenting in ipsilateral iliac vein. There were 6 male and 9 female patients, with a mean age of 57.4 years (ranging from 36 to 71 years). All patients underwent Duplex ultrasonography for diagnosis of DVT. The location of thrombosis was femoro-ilio-caval vein in 2 cases, bilateral iliac vein in 1 case and left iliofemoral vein in 12 cases. All patients had leg swelling and 12 cases had severe leg pain. The mean time of symptomatic DVT occurring at operation was 3.3 d. The factors related to DVT were operation in 6 cases, DVT reoccur in 2 cases. Coexist diseases were digestive tract bleeding in 1 case, gastric ulcer in 1 case, hypertension in 3 cases and 1 case had cerebral infarction. The inferior vena cava filter was inserted before thrombectomy, iliac vein compression and residual stenosis were treated with a self-expandable stent after thrombectomy., Results: Intraoperative venography showed severe venous stenosis in all patients including 80% of iliac vein compression syndrome, 18 self-expandable stents were inserted successfully, the procedural successful rate was 100%, the 30-day mortality rate was 0.One case was suffered from hematoma at incision after operation. 3 patients were lost during follow-up. Median follow-up was 10.3 months (ranging from 2 to 26 months). There was no case of re-thrombosis. Leg pain was disappeared in all cases and only 2 patients showed slight leg swelling after excise., Conclusion: Combined surgical thrombectomy and endovascular treatment for patients with acute symptomatic iliofemoral venous thrombosis is an effective and safe technique with low morbidity and good clinical results.

Objective: To measure the diameter and length of infrarenal inferior vena cava (IVC) in Shandong Peninsula adult through digital subtraction angiography (DSA) for better vena cava filter (VCF) choice and placement., Methods: From April 2008 to June 2010, 83 discontinuous patients (49 males and 34 females, mean age 56.4 years) with deep venous thrombosis (DVT) of lower extremity were placed VCF through DSA according to ACCP-8. During operation, diameter and length of infrarenal IVC were measured. At the same time, the renal vein location and the type of the IVC were identified to help the VCF choice., Results: All the VCFs were placed successfully, no complications occurred. The diameter of infrarenal IVC was 10 to 26 mm with a mean of (19 ± 5) mm. The average length from beginning of IVC to the lower renal vein was (10.6 ± 2.8) cm. The renal vein was located between the first and second lumbar vertebra, the IVC beginning was located between the fourth and fifth lumbar vertebra., Conclusions: Diameter and length measurement of infrarenal IVC is helpful to the VCF selection and the domestic VCF research. Vena cava angiography is very important to the accurate placement of VCF.

Objective: To investigate the efficacy of anticoagulation and thrombolysis for deep venous thrombosis via local vein approach and peripheral vein approach to guide clinical treatment., Methods: There were 225 patients with deep venous thrombosis admitted from January 2001 to May 2008. The cases were divided into two groups by therapy procedures. The patients in group A were treated by deep femoral vein catheter-directed anticoagulation and thrombolysis, including a total number of 71 patients, with right lower extremity in 20 patients, left lower extremity in 47 patients and bilateral lower extremities in 4 patients. One hundred and fifty-four patients were included in group B with anticoagulation and thrombolysis through peripheral vein, among them right lower extremity in 27 patients, left lower extremity in 121 patients and bilateral lower extremities in 6 patients. The efficacy was evaluated and compared by observing clinical symptoms and measuring of changes in limb circumference., Results: Symptoms were alleviated in all patients in 3 d after the treatment, but the efficacy of group A was better than group B (94.4% vs.69.5%, P < 0.01). The efficacy of group A was also better than group B in 7 days after treatment, but with no significant difference (85.9% vs. 75.3%, P > 0.05). A mean follow-up period was (43 ± 18) months. There was no significant difference in incidence of complication and recurrence between two groups., Conclusions: The earlier efficacy of anticoagulation and thrombolysis via femoral vein approach is better than via peripheral vein approach in earlier period of deep venous thrombosis. While peripheral intravenous therapy has also good results after long-term treatment.

Objective: To discuss the efficacy of anticoagulation on patency post-permanent inferior vena caval filter (IVCF) placements., Methods: The patients with deep vein thrombosis (DVT) of the lower extremity who were accepted permanent IVCF placement from December 2001 to December 2007 were reviewed retrospectively. Data on vital status, filter thromboembolism, anticoagulation time, and so on were obtained through follow-up. One hundred and thirty eight patients (75 male and 63 female) with a mean age of 65 years were enrolled in the study. All the patients were divided into non-anticoagulation group, anticoagulation group A with taking warfarin less than 6 months, or anticoagulation group B with taking warfarin more than 6 months. chi(2) test, t test, Kaplan-Meier survival curve, Log-rank test were used for statistics analysis., Results: Sixteen patients died, and 1 of them died of pulmonary embolism. Including the 1 patient mentioned before, there were 19 patients (13.8%) suffered from filter thromboembolism. Upon chi(2) test, there were no significant differences (P = 0.288) on the patency rates between non-anticoagulation, anticoagulation group A and anticoagulation group B (87.8%, 75.0%, and 88.3% respectively). Upon Kaplan-Meier survival analysis, there were still no significant differences (P = 0.227) on the mean patency time and the cumulate rates of patency at the 1st or 3rd year between the 3 groups (87.1%, 80.0%, 94.8% and 87.1%, 74.3%, 85.4% respectively)., Conclusion: Anticoagulation has no efficacy on patency post-permanent IVCF placements.

Objective: To assess the effectiveness and safety of non-permanent filter in preventing pulmonary embolism (PE) caused by deep venous thromboembolism (DVT)., Methods: The clinical data of 12 patients who were implanted with non-permanent filter for documented deep venous thromboembolism in Peking Union Medical College Hospital from September 2003 to June 2006 were retrospectively analyzed., Results: Among these 12 patients, 10 were implanted with temporary filters, and 2 with retrievable filters. All the 12 operations were successful without major complications. In the 10 patients who received temporary filters, filters were smoothly removed after 4 weeks in 9 patients, while one patient was further treated with anticoagulation therapy for 12 weeks because large emboli were entrapped by filter. In the 2 patients who received retrievable filters, filter were smoothly removed 2 weeks later in one patient; however, in another patient, the filter was left inside because large emboli were entrapped by filter. In all the 12 patients, emboli were entrapped in 6 filters (50%), in which the emboli were larger than 2 cm in 2 patients, larger than 1 cm but less than 2 cm in 1 patient, and less than 1 cm in 3 patients. PE scanning was performed in 10 patients before primary implantation, and PE was found in 5 patients. PE scanning was performed in 8 patients 6 months after implantation, and minor PE was found in 4 patients, whose symptoms and affected pulmonary artery were obviously improved. All patients received regular follow-up (ranged from 3 months to 2 years), 1 patient died of malignant tumor 4 months after operation, 1 patient suffered inferior vena cava occlusion due to large emboli entrapped by the temporary filter, and 1 patient experienced the recurrence of symptomatic DVT. Symptoms were improved in all the 5 patients with PE., Conclusions: Non-permanent filter can safely and effectively protect patients from PE. More standardized criteria for placement and protocols to ensure timely removal should be developed and implemented.

Venous thromboembolism is a common vascular disease with clinically high morbidity and mortality. Prevention and treatment strategies should be based on risk stratification. Anticoagulation remains the mainstay of therapy for patients with venous thromboembolism. More evidence-based studies should be performed to establish the strategy of prevention and treatment for venous thromboembolism in China.