Effects of Human Postures on Flow Characteristics in Iliac Vein Compression Syndrome / 医用生物力学

Objective To investigate effects of human postures on flow characteristics of iliac vein compression syndrome. Methods The numerical model of iliac vein was reconstructed from CT images of a typical patient with pelvic-type iliac vein compression syndrome with collateral veins. Based on the computational fluid dynamics method, the non-Newtonian model and the porous media model were adopted to describe effects of abnormal structures on blood flow and acquire the wall shear stress and pressure of iliac vein. The discrete phase model was used to study the residence conditions of erythrocytes under three human postures. Results The pressure gradient at two ends of the compressive region was lowest under lying state, while the iliac vein showed a high pressure under sitting and walking states. The local maximum wall shear stresses under three postures were found at narrow segment of the collateral vein and convergence region of two flows of right iliac vein. The maximum shear stress was largest under lying state and smallest under sitting state. The blood residence time of 52.2 s in the left iliac vein was the longest under sitting state. The residence time of 14.8 s was shortest under lying state. The blood residence time was 23.8 s under walking state. Conclusions Porous media model used to simulate the effect of abnormal structures was highly consistent with the angiography data. The venous hypertension under sitting and walking states was consistent with the clinical results, and the lying state could relieve the hypertensive condition. In terms of wall shear stress and blood residence time in iliac vein, the continual change between three human postures would cause endothelial damage and blood flow stasis alternately, thus increase the risk of thrombosis.

Fully protruding into the inferior vena cava deployment of braided stent in the treatment of iliac compression syndrome / 中华普通外科杂志

Objective:To evaluate the clinical efficacy of metal braided stent deployed by fully protruding into the inferior vena cava for the treatment of iliac vein compression syndrome(IVCS).Methods:The clinical data of patients with IVCS treated with interwoven nitinol mesh stent protruding into the inferior vena cava and released from Jan 2018 to May 2021 in our center were retrospectively analyzed.Results:A total of 118 patients were included in this study. Among them, 7 cases were complicated with acute thrombosis, 3 cases were complicated with post thrombotic syndrome (PTS), and 108 cases were no more thrombotic iliac vein compression. The technical success rate was 100%, with an average of 2.03±0.77 stents implanted. Of the 23 ulcer patients, 18 ulcers healed after intervention, and the healing rate was 78.26%. The postoperative CEAP grade was significantly improved ( t=11.54, P<0.01), and the primary patency rate and second patency rate were 97.46% and 98.31% at 1 year after intervention. Conclusion:The fashion of fully protruding into inferior vena cava deployment in the treatment of iliac vein compressive disease has a high patency rate and satisfactory clinical efficacy.

Hemodynamic Study on the Relationship Between Collateral Circulation Caused by Iliac Vein Compression and Deep Venous Thrombosis / 医用生物力学

Objective To explore the relationship between the establishment of collateral circulation caused by iliac vein compression syndrom(IVCS) and the deep venous thrombosis (DVT). Methods Different types of ideal collateral circulation models and IVCS patient-specific models were numerically simulated using computational fluid dynamics (CFD) in combination with the blood stasis model. The relationship between blood retention and collateral types and cross-sectional area was studied, and the relationship with thrombosis was explored. Results Wall shear stress (WSS) at the distal end part of each ideal model was 0.3 Pa. After four cardiac cycles, the residual blood stayed at the stenosis and the distal end part for the lumbar ascending and pelvic type models, the old blood volume fraction (OBVF) varied with collateral cross-sectional areas, ranging from 5%-90% and 70%-80%, respectively. The OBVF of the coexistence model was above 80%. The WSS at the distal end part of the patient-specific model was 0.9 Pa, and the OBVF at the distal end part was 51.5%. Conclusions The stenosis and the distal end part are most prone to blood stasis, and closely related with DVT. The larger the collateral cross-sectional area, the more serious the blood stagnation. Blood stagnation of the coexistence model is higher compared with the model with lumbar ascending type and pelvic type.

The value of three-dimension digital subtraction angiography in diagnosis and treatment of iliac vein compression syndrome / 中华普通外科杂志

Objective:To evaluate the application value of three-dimension digital subtraction angiography (3D-DSA) in the diagnosis and treatment of iliac vein compression syndrome (IVCS).Methods:A retrospective analysis was made on 171 patients with a tentative diagnosis of IVCS based on signs, symptoms, and finding of CTV or MRV, and iliac vein angiography. The diagnostic efficacy of MRV, 2D-DSA and 3D-DSA were analyzed. The imaging advantages of 3D-DSA in the diagnosis and treatment of IVCS were evaluated.Results:Ninty-three patients underwent MRV and 3D-DSA simultaneously, 101 patients had 2D-DSA and 3D-DSA simultaneously. 3D-DSA was taken as gold standard, the diagonotic sensitivity, specificity, Youden index of MRV was 75.61%, 72.73% and 0.48 respectively. The sensitivity, specificity, Youden index of 2D-DSA was 90.22%, 100% and 0.90 respectively. There are significant differences in the diagonotic sensitivity between MRV and 3D-DSA, 2D-DSA and 3D-DSA ( P<0.05). There is no significant difference in the diagonotic specificity between MRV and 3D-DSA, 2D-DSA and 3D-DSA ( P=1.000). In this study, we found that 3D-DSA has greater imaging evaluation advantages in preoperative evaluation, intraoperative guidance and immediate postoperative reexamination in the diagnosis and treatment of iliac vein disease. Conclusions:3D-DSA can improve the detection rate of IVCS, and has its advantage in imaging evaluation.

CT angiography in the evaluation of the risk of pulmonary embolism in patients with iliac vein compression syndrome and acute iliofemoral vein thrombosis / 中华放射学杂志

Objective:To evaluate the risk and influencing factors of pulmonary embolism in patients with iliac vein compression syndrome (IVCS) and acute iliofemoral vein thrombosis by CT pulmonary angiography combined with CT venography of inferior vena cava.Methods:The data of 166 patients with acute left iliofemoral vein thrombosis diagnosed in the Affiliated Hospital of Jining Medical University from July 2016 to June 2020 were analyzed retrospectively. All patients underwent one-stop CT pulmonary angiography combined with inferior vena cava CT venography. The patients were divided into IVCS group (101 cases) and non-IVCS group (65 cases) according to the presence or absence of IVCS. The general data of the patients, the stenosis rate of left common iliac vein, the presence of inferior vena cava floating thrombosis, the presence of large pelvic collateral veins, the detection of pulmonary embolism and the pulmonary artery obstruction index of the two groups were compared, and multivariate logistic regression and multiple linear regression were used to analyze the influencing factors of the incidence and severity of pulmonary embolism in IVCS group.Results:There were significant differences in the stenosis rate of left common iliac vein [(68±8)% vs (25±14)%, t=-25.300, P<0.001], the incidence of inferior vena cava floating thrombosis [25/101, 31/65, χ2 =9.310, P=0.002], the length of inferior vena cava floating thrombosis [17.2 (10.9, 27.8)mm vs 27.4 (20.1, 55.9) mm, Z=-2.316, P=0.021], the incidence of pulmonary embolism (43/101 vs 41/65, χ2 =6.651, P=0.010) and the pulmonary artery obstruction index [(10.0% (5.0%, 17.5%) vs 22.5% (10.0%, 30.0%), Z=-3.490, P<0.001] between IVCS group and non-IVCS group. In the IVCS group, multiple logistic regression analysis revealed that the stenosis rate of left common iliac vein [β=-1.964, OR(95%CI) 0.140(0.031-0.638), P=0.011] and inferior vena cava floating thrombosis [β=1.212, OR(95%CI) 3.360(1.566-7.209), P=0.002] was independent factors for the occurrence of pulmonary embolism. Multiple linear regression showed that the influence of inferior vena cava floating thrombosis on the pulmonary artery obstruction index was statistically significant (b=0.352, t=2.410, P=0.021). Conclusion:The incidence and severity of pulmonary embolism in patients with IVCS and acute left iliofemoral vein thrombosis are lower than those without IVCS, and the presence or absence of inferior vena cava floating thrombosis is an important factor affecting the severity of pulmonary embolism.

Comparison of intravascular ultrasound and venography in the intraoperative evaluation of iliac vein compression syndrome / 中华普通外科杂志

Objective@#To compare intravascular ultrasound (IVUS) with venography in the intraoperative evaluation of iliac vein compression syndrome (IVCS).@*Methods@#From Sep 2017 to Mar 2018, consecutive patients with suspicious iliac vein compression, underwent both venography and IVUS. The results were compared between IVUS and venography.@*Results@#40 patients with 48 limbs were enrolled. Venography underestimated both the diameter and area stenosis compared with IVUS (39.63%±15.48% vs. 64.97%±16.42%, P<0.001; 51.83%±18.23% vs. 59.19%±14.17%, P=0.021, respectively). The eccentricity detected by venography was lower than IVUS (0.69±0.17 vs. 0.93±0.17, P<0.001). Taking IVUS as gold standard, the sensitivity and the specificity of venography for detecting a ≥50% stenosis was 18.92% and 81.82%, and the intertechnique agreement was extremely low between venography and IVUS (κ=0.004).@*Conclusion@#Compared with IVUS, venography underestimated the degree of stenosis in IVCS. The sensitivity of venography in detecting a significant stenosis was very low.

Comparison of intravascular ultrasound and venography in the intraoperative evaluation of iliac vein compression syndrome / 中华普通外科杂志

Objective To compare intravascular ultrasound (IVUS) with venography in the intraoperative evaluation of iliac vein compression syndrome (IVCS).Methods From Sep 2017 to Mar 2018,consecutive patients with suspicious iliac vein compression,underwent both venography and IVUS.The results were compared between IVUS and venography.Results 40 patients with 48 limbs were enrolled.Venography underestimated both the diameter and area stenosis compared with IVUS (39.63％ ± 15.48％ vs.64.97％ ±16.42％,P＜0.001;51.83％ ±18.23％ vs.59.19％ ±14.17％,P=0.021,respectively).The eccentricity detected by venography was lower than IVUS (0.69 ±0.17 vs.0.93 ±0.17,P ＜0.001).Taking IVUS as gold standard,the sensitivity and the specificity of venography for detecting a ≥50％ stenosis was 18.92％ and 81.82％,and the intertechnique agreement was extremely low between venography and IVUS (κ =0.004).Conclusion Compared with IVUS,venography underestimated the degree of stenosis in IVCS.The sensitivity of venography in detecting a significant stenosis was very low.

Sonographic manifestations of iliac vein compression syndrome in elderly patients / 中华老年医学杂志

Objective To evaluate the sonographic manifestations of iliac vein compression syndrome (IVCS)in elderly patients.Methods Sonographic data (including gray scale,color Doppler and spectral Doppler ultrasound)of 26 patients diagnosed with IVCS by venogram were analyzed retrospectively,and their sonographic manifestations were categorized.Results The sonographic manifestations of IVCS can be categorized into three types.Type one presented as iliac vein stenosis and an increase in focal blood flow velocity(5/26,19.2％).Type two presented as masses around the iliac vein and vein thrombosis(4/26,15.4％).Type three manifested thrombosis in the iliac vein and deep veins of lower extremity,without obvious masses or iliac vein stenosis (17/26,65.4％).Of all patients,nine were diagnosed with IVCS by ultrasound(9/26,34.6％).The other 17 patients were confirmed by venogram after suggestive ultrasound signs.Conclusions Ultrasound plays an important role in the early diagnosis of IVCS and can help decide on the need for further diagnostic tests.

Clinical value of magnetic resonance venography in diagnosing Cockett syndrome / 介入放射学杂志

Objective To evaluate non-enhancement magnetic resonance venography (MRV) of iliac vein in diagnosing Cockett syndrome.Methods Magnetic resonance iliac venography was performed with Ingenia 3.0 T superconducting type MRI system.Abdominal surface coil was employed.The scanning sequences included M2DIPEAR (TR/TE=45/5.8 ms,flip angle=60°),THRIVE (TR/TE=6.8/3.5 ms,flip angle=10°),BTFESPAIR (TR/TE=3.4/1.7 ms,flip angle=80°) and FLAIR (TR/TE=9 000/120 ms,flip angle 90°).The layer thickness of 3 mm was used in all scanning,and the average number of acquisition was 3 times.Results On MRV imaging,Cockett syndrome was characterized by narrowed anteroposterior diameter and broadened transverse diameter of the compressed iliac vein,and curved impression could be seen on its anterior border,and collateral vessel formation could be observed.The mean diameters of the left iliac veins in the light,mnedium and severe patients with Cockett syndrome were 7.52,4.83 and 2.76 mm respectively,with the average compression ratios being 37％,69％ and 83％ respectively.Conclusion Non-enhanced MRV is a feasible method for the diagnosis of iliac vein stenosis,this examination is especially suitable for the checking needs of specific population.

Percutaneous mechanical thrombectomy with subsequent iliac vein stent implantation accomplished by single-procedure for acute deep venous thrombosis of lower extremity: preliminary results in 12 cases / 介入放射学杂志

Objective To evaluate the feasibility,safety and effectiveness of percutaneous mechanical thrombectomy (PMT) and iliac vein stent implantation which are accomplished by single-procedure in treating acute deep venous thrombosis (DVT) of lower extremity.Methods During the period from December 2014 to January 2016,a total of 12 patients with acute DVT of lower extremity,including 3 males and 9 females with a mean age of (50.42±16.21) years old,were admitted to authors' hospital to receive treatment.Clinically,all patients presented with left leg swelling and pain.Central type of DVT was seen in 3 patients and mixed type of DVT was found in 9 patients.Preoperative placement of inferior vena cava filter was employed in all patients,which was retrieved after the treatment.PMT by using Angio Jet thrombus removal catheter,balloon angioplasty,and iliac vein stent implantation were successively carried out during the same procedure.When residual thrombus was identified on checkup angiography the catheter sheath would be reserved,and the thrombolytic therapy would be adopted.The patients were followed up at outpatient clinic at one,3,6 and 12 months after the treatment,and reexamination of color ultrasound and/or lower limb venography was used to assess the blood flow in the deep veins and in the stents.Results The combination of several therapies was accomplished in a single procedure,the technical success rate was 100％.The used time for the operation was 60-110 minutes,with a mean of (96.25±14.32) minutes.The used time for thrombus aspiration was 51-280 seconds,with a mean of (199.92±74.89) seconds.Thrombus clearance rate of grade Ⅲ was obtained in 10 patients,and thrombus clearance rate of grade Ⅱ was seen in 2 patients;the clinical symptoms were improved in all patients.Except some patients complained of different degrees of pain during the performance of balloon dilatation of left common iliac vein,no serious complications such as pulmonary embolism,severe hemorrhage,etc.occurred.The patients were followed up for (5.58±2.75) months;color ultrasound and/or lower limb venography performed in 11 patients showed that the blood flow in deep veins and iliac vein stents was unobstructed,and relapse of DVT was observed in one patient with cerebral astrocytoma.Conclusion For the treatment of DVT of lower extremity,PMT combined with iliac vein stent implantation that is accomplished by single-procedure is safe and feasible,its preliminary clinical results are satisfactory.

The application of combined venography in the diagnosis of iliac vein compression syndrome with dual-source CT / 实用放射学杂志

Objective To explore the clinical value of the combined dual-source CT venography(CTV)for the diagnosis of iliac vein compression syndrome(IVCS).Methods 43 patients with clinically suspected IVCS underwent CTV examination.Among them,22 cases were assessed with combined CTV while 21 cases were given conventionally indirect CTV.The lower extremity deep vein was scanned from foot to head.The dual-energy technology was applied for data acquisition.Results Two kinds of CTV methods could be used directly for diagnosing IVCS and checking the asymptomatic mild iliac vein compression.32 IVCS patients were diagnosed by CTV.In 27 cases with deep venous thrombosis(DVT),the average diameter of the left iliac vein was(3.23 ± 1.45)mm and the average compression rate was 67%.The differences were statistically significant in comparisons of the average diameter of left iliac vein between IVCS patients with or without DVT and patients without IVCS.The image quality scores of bidirectional CTV were higher than indirect CTV with statistically significant difference.Conclusion Combined CTV is a feasible technique for lower extremity venography.The image quality of combined CTV is better than conventional indirect CTV with greater clinical value.

Underlying CT anatomy and subtype diagnosis of iliac vein compression syndrome / 中华放射学杂志

Objective To explore the underlying anatomy of iliac vein compression syndrome (IVCS) using CT, and discuss the imageological index for subtype diagnosis and potential clinical significance. Methods We retrospectively analyzed the imageological data of 69 IVCS patients from July, 2009 to June, 2014. According to CT findings, patients were categorized to simple IVCS (sIVCS, the iliac vein is compressed by only the anterior iliac artery, n=22), lumbar degeneration?related IVCS ( dIVCS, besides the iliac artery, the lower lumbar degenerative changes including osteophyte, protruded disc, etc. pressed the iliac vein from the back, n=33) and other IVCS causes (oIVCS, including tuberculosis, inflammation and fracture hematoma of the lumbar spine, n=14); meanwhile, 69 age? and sex?matched subjects was set as a control group. Evaluated indexes were onset age, course of lower limb swelling and pain, size of the iliac vein tunnel ahead lumbar (IVTAL), lower lumbar spine forward curvature angle (LLSCA), iliac vein?pressed signs by lower lumbar degeneration, compression sites, scope of deep venous thrombosis and interventional therapeutic effect. The differences of those indexes of various groups were compared. Data as onset age, course of disease, sizes of IVTAL and LLSCA were evaluated using variance analysis of the general linear model, with Bofferroni test correction for multiple comparisons. Data as iliac vein?pressed site, scope of venous embolism and therapeutic effect were assessed by crossing table χ2 test. All statistical analyses were performed using SPSS17.0 software (SPSS company, Chicago, USA). Bilateral P≤0.05 were considered to be significant. Results The onset mean age was (61.5 ± 10.6) yr. in dIVCS, (42.3 ± 6.5)yr in sIVCS. and(53.1 ± 16.8)yr. in oIVCS with a significant difference ( F=11.030, P<0.01). Mean sagittal diameter of the IVTAL and LLSCA were(2.3±0.5)mm and(121.8±5.4)° in dIVCS and(2.5± 0.5)mm and(124.4 ± 3.9)° in sIVCS, respectively; which were smaller than those of control group [(6.4 ± 1.6)mm and(127.5 ± 7.3)° , respectively ] and oIVCS [(5.9 ± 2.3)mm and(129.5 ± 5.9)° , respectively ](F=125.275,P<0.01 for sigittal diameter and F=7.95,P<0.01 for LLSCA). The degenerative changes compressing the iliac vein of dIVCS had 41 sites of 33 patients which were respectively the discal forward protrusion or bulge (51%, 17/33), vertebral anterior osteophyte (50%, 16/33)and lower lumbar vertebrae slippage (19%,8/33). The compression sites of dIVCS located exactly anterior to the fifth lumbar(18/33, 56%), the intervertebral disk between the fourth and fifth lumbar(9/33, 26%), the right front (3/33, 9%) and left front (3/33, 9%) of the fifth lumbar, however, that of sIVCS sited the right front(14/22, 64%), exactly the front(4/22, 18%)of the fifth lumbar and exactly anterior(4/22, 18%)to the intervertebral disk between the fourth and fifth lumbar, with a significant difference of location distribution(χ2=19.305, P<0.01). In sIVCSs, deep vein thrombosis of all exceeded the iliac vein length and implicated the femoral vein by 27%(6/22)and the popliteal vein by 73%(16/22), while in dIVCSs 18%(6/33)patients had deep vein thrombosis in the iliac vein, 30%(10/33)in the femoral vein and 52%(17/33)in the popliteal vein, and in oIVCSs, 30%(4/14)patients had deep vein thrombosis in the iliac vein, 40%(6/14)in the femoral vein and 30%(4/14)in the popliteal vein, with a significant difference of thrombosis scope(χ2=9.28, P<0.01). 86%sIVCSs needed intravenous stent?implanted operation to obtain effective treatment, only 52%dIVCSs were performed stent?implanted operation for effective therapy, none of oIVCSs had stent?implanted operation before the iliac vein recanalization. Conclusion CT can precisely display the pathological anatomy features of different IVCS patients, which can potentially help clinicians plan accurate treatment strategy.

Endovascular Treatment for Iliac Vein Compression Syndrome in 112 Cases / 中国微创外科杂志

Objective To investigate the clinical efficacy of endovascular treatment for iliac vein compression syndrome (IVCS) in 112 cases. Methods From September 2011 to June 2015, 112 cases of IVCS (Cockett syndrome) were treated in our hospital with endovascular methods .The case numbers of different CEAP ( clinical etiological anatomical pathophysical ) classifications were C2 (45 cases), C3 (23 cases), C4 (19 cases), C5 (11 cases) and C6 (14 cases).All the cases were diagnosed by venography .The operations started from puncturing the ipsilateral veins .The stenotic degree and compressed intensity of iliac vein were evaluated by the minimum diameter with low pressure balloon .And then a stent was placed into after percutaneous transluminal angioplasty ( PTA) when residual stenosis was more than 50%.The occlusive segment was dilated by 8 mm diameter balloon firstly , and catheter directed thrombolysis treatment was applied if thrombus was detected .The PTA and stenting were performed when the thrombus was completely removed .The improvement of clinical symptoms was observed after operation and the patients were followed up by ultrasound and venograghy . Results Nine cases were given PTA only , and the other 103 cases underwent stent placement . Postoperative venography showed collateral vessels were disappeared in 22 cases, obviously decreased in 56 cases and mildly decreased in 34 cases.The average difference of swelling leg ’s circle was diminished from (2.56 ±0.88) cm pre-operation to (0.93 ±0.71) cm post-operation, while the average area of skin ulcer was diminished from (6.34 ±3.78) cm2 pre-operation to (2.13 ±1.88) cm2 post-operation, all of which were statistically significant (t =20.24 and 7.19,P=0.000).A total of 86 cases were successfully followed up during a period from 2 months to 45 months (average, 19.2 months).The patency rate of treated iliac vein 12 months after operation was 76.2%in the PTA group, and in the PTA with stenting group was 96.7%, 88.6%, and 86.1%, respectively, at 12, 24, and 36 months after operation, in which a statistical significance was detected (log-rank χ2 =30.32, P=0.000).The patency rate in diameter ≥16 mm group was 95.2%and 95.2%, respectively, at 12 and 24 months after operation, while in diameter <16 mm group was 97.0%and 93.3%, respectively, in which no statistical significance was detected (log-rankχ2 =0.39, P=0.532).Thrombotic complication was found in 2 cases during the follow-up period , including 1 case of iliac vein thrombosis at 1 month and 1 case of thrombus in contralateral leg 8 months later .According to the results of venography in 78 cases at 12 months after operation , restenosis was found in 5 out of 6 cases in the PTA group, and the patency rate in the stent placement group was 95.8%(69/72).No stent migration was found . Conclusion Comfortable clinical results were obtained after endovascular therapy for iliac vein compression syndrome , and the application of stenting could increase the middle and long term patency rate of treated vessels .

Multi-slice spiral CT venography and digital subtraction venography for the diagnosis of iliac vein ;compression syndrome：a comparison study / 介入放射学杂志

Objective To evaluate multi-slice spiral CT venography (MSCTV) and digital subtraction venography (DSV) in diagnosing iliac vein compression syndrome (IVCS) and secondary thrombosis. Methods The imaging materials, including MSCTV and DSV performed before and after the thrombolysis therapy, of 38 patients with clinically-suspected IVCS were collected. The inner diameters of the compressed iliac veins were measured on MSCTV images and the compression ratio was calculated. Usingχ2 test, the detection rates of IVCS by MSCTV and DSV were compared. Results Of 38 patients, IVCS was detected by MSCTV in 29, by pretreatment DSV in 20 and by post-treatment DSV in 29. The difference in the detection rate of IVCS between MSCTV and pre-treatment DSV was statistically significant (χ2=4.65, 0.010.05). Conclusion For the diagnosis of IVCS, MSCTV is superior to pre-treatment DSV in the diagnostic accuracy of iliac vein compression syndrome. Therefore, MSCTV should be used as the preferred method of examination.(J Intervent Radiol, 2015, 24:301-305)

Stent Compression in Iliac Vein Compression Syndrome Associated with Acute Ilio-Femoral Deep Vein Thrombosis

OBJECTIVE: This study was conducted to evaluate stent compression in iliac vein compression syndrome (IVCS) and to identify its association with stent patency. MATERIALS AND METHODS: Between May 2005 and June 2014, after stent placement for the treatment of IVCS with acute ilio-femoral deep vein thrombosis, follow-up CT venography was performed in 48 patients (35 women, 13 men; age range 23-87 years; median age 56 years). Using follow-up CT venography, the degree of the stent compression was calculated and used to divide patients into two groups. Possible factors associated with stent compression and patency were evaluated. The cumulative degree of stent compression and patency rate were analyzed. RESULTS: All of the stents used were laser-cut nitinol stents. The proportion of limbs showing significant stent compression was 33%. Fifty-six percent of limbs in the significant stent compression group developed stent occlusion. On the other hand, only 9% of limbs in the insignificant stent compression group developed stent occlusion. Significant stent compression was inversely correlated with stent patency (p < 0.001). The median patency period evaluated with Kaplan-Meier analysis was 20.0 months for patients with significant stent compression. Other factors including gender, age, and type of stent were not correlated with stent patency. Significant stent compression occurred most frequently (87.5%) at the upper end of the stent (ilio-caval junction). CONCLUSION: Significant compression of nitinol stents placed in IVCS highly affects stent patency. Therefore, in order to prevent stent compression in IVCS, nitinol stents with higher radial resistive force may be required.

Endovascular treatment of iliac vein compression syndrome:analysis of 33 cases / 中国医师进修杂志

Objective To evaluate the clinical effect of the endovascular treatment of iliac vein compression syndrome.Methods Thirty-three patients with iliac vein compression syndrome were treated with endovascular treatment.Of which,edema and varicose vein of the left lower extremity in 29 patients,complicated with acute deep vein thrombosis of left lower extremity in 3 patients,post deep venous thrombosis syndrome in 1 patient.Balloon dilatation and stent implantation were performed in all 33 patients.The diameter of balloon was 10-12 mm,diameter 12-14 mm Bard self expandable stent.Five patients with varicose vein and ulcer of left lower extremity were treated with two stage operation.Results The diagnosis was confirmed by left lower extremity deep veins angiography.There was no death patient,and no hematoma of hematoma locus.Follow-up for 3-30 months,the rate of follow-up was 100％(33/33).The edema of the lower extremity was markedly reduced or disappeared in 28 patients.Color Doppler ultrasound and left lower extremity angiography showed that the stent was unobstructed,no stent occlusion and new onset thrombosis cases.Conclusion Endovascular treatment is safe,effective with few complications,and is the first choice for the treatment of iliac vein compression syndrome.

Ipsilateral leg swelling after renal transplantation as an alarming sign of Iliac vein stenosis

Iliac vein stenosis is a rare vascular complication of renal transplantation that may compromise allograft function if not recognized and corrected in a timely fashion. Because chronic venous stenosis may remain undiagnosed for several years, a high index of suspicion should be maintained until diagnosing this rare disease. A 56-year-old renal transplant recipient presented with unilateral leg swelling and renal dysfunction 16 years after transplantation. Computed tomography excluded deep vein thrombosis and revealed tight iliac vein stenosis on the side of the renal transplant. Following angiographic confirmation of the stenosis, endovascular treatment was successfully performed with a purposefully designed, self-expanding, venous stent. Ipsilateral leg swelling is an alarming sign for the diagnosis of iliac vein stenosis after renal transplantation. Percutaneous intervention with venous stent placement seems to be a safe and effective treatment of this rare condition.

Endovascular Treatment for Iliac Vein Compression Syndrome: a Comparison between the Presence and Absence of Secondary Thrombosis

OBJECTIVE: To evaluate the value of early identification and endovascular treatment of iliac vein compression syndrome (IVCS), with or without deep vein thrombosis (DVT). MATERIALS AND METHODS: Three groups of patients, IVCS without DVT (group 1, n = 39), IVCS with fresh thrombosis (group 2, n = 52) and IVCS with non-fresh thrombosis (group 3, n = 34) were detected by Doppler ultrasonography, magnetic resonance venography, computed tomography or venography. The fresh venous thrombosis were treated by aspiration and thrombectomy, whereas the iliac vein compression per se were treated with a self-expandable stent. In cases with fresh thrombus, the inferior vena cava filter was inserted before the thrombosis suction, mechanical thrombus ablation, percutaneous transluminal angioplasty, stenting or transcatheter thrombolysis. RESULTS: Stenting was performed in 111 patients (38 of 39 group 1 patients and 73 of 86 group 2 or 3 patients). The stenting was tried in one of group 1 and in three of group 2 or 3 patients only to fail. The initial patency rates were 95% (group 1), 89% (group 2) and 65% (group 3), respectively and were significantly different (p = 0.001). Further, the six month patency rates were 93% (group 1), 83% (group 2) and 50% (group 3), respectively, and were similarly significantly different (p = 0.001). Both the initial and six month patency rates in the IVCS patients (without thrombosis or with fresh thrombosis), were significantly greater than the patency rates of IVCS patients with non-fresh thrombosis. CONCLUSION: From the cases examined, the study suggests that endovascular treatment of IVCS, with or without thrombosis, is effective.

Iliac Vein Compression Syndrome in Spinal Cord Injury

OBJECTIVE: Iliac vein compression syndrome is a well-recognized anatomic variant that is associated with the development of symptomatic deep venous thrombosis (DVT) of the left iliac vein. However, its relation with DVT in spinal cord injury has not been established. The purpose of this study was to determine the relation between iliac vein compression syndrome and DVT in spinal cord injured patients. METHOD: Thirteen spinal cord injured patients diagnosed with DVT from January 2002 to December 2003 were evaluated. After ascending venography, the catheter-directed thrombolytic therapy and balloon angioplasty with stent insertion after 24 hours of thrombolytic therapy were done. RESULTS: Twelve of 13 patients showed that the left iliac vein was compressed by the right iliac artery, with thrombosis shown in the distal venous segment of the crossover point and had a collateral formation. All 12 patients had residual stenosis of left iliac vein in spite of the thrombolytic therapy. The unimpeded venous flow of iliofemoral veins was revealed after the balloon angioplasty with stent insertion. CONCLUSION: We suggested that the proper evaluation and management about iliac vein compression syndrome be considered when residual stenosis was persistent through the chemical dissolution in spinal cord injured patient with left iliac vein thrombosis.

Evaluation of Catheter-Directed Thrombolysis for Acute Deep Vein Thrombosis / 日本心臓血管外科学会雑誌

We report the efficacy of catheter-directed thrombolysis (CDT) for acute deep vein thrombosis. Between January 2003 and August 2004, 20 patients were treated with CDT for occlusive femoral, ilio-femoral and vena caval thrombosis, for less than 2 weeks from onset. Average age was 56.4 years (range 30-78 years), 11 patients were male, and the duration of leg symptoms was 4.4 days (range 1-12 days). Routine temporary inferior vena caval filters were used, and a multi-lumen catheter was inserted from the popliteal vein. Urokinase was used via the catheter by the combination drip infusion method and pulse-spray method. All patients received heparin and stasis of venous flow was prevented with intermittent pneumatic compression. If thrombus remained, mechanical thrombolysis was necessary. Metallic stents were implanted for iliac vein compression syndrome and organized thrombus. Venographic severity score (VS score) and extremity circumference were used to evaluate the effects of treatment. The duration of the treatment was 5.0±0.28 days (range 2-9 days) and the total dosage of urokinase was 1, 025, 000±57, 000 units (range 360, 000-1, 680, 000 unit). One (5%) iliac vein compression syndrome and two (10%) organized thrombi were treated by implanted metallic stents. Giant thrombi was captured by temporary inferior vena caval filters in two patients, but there was no pulmonary embolism. Two patients had thrombophilia, one was antiphospholipid syndrome and one was protein S deficiency. There was an early recurrence in one patient and re-CDT was needed. The VS score deteriorated to 6.2±2.5 (post CDT) significantly (<i>p</i><0.0001) from 26.2±6.3 (pre CDT). CDT for acute deep vein thrombosis was effective and its early outcome was acceptable.