Underlying Anatomy and Typing Diagnosis of May-Thurner Syndrome and Clinical Significance: An Observation Based on CT

Intra-abdominal Venous Thromboses and Their Management

While a plethora of articles discuss management of deep venous thromboses in extremities, there is a relative scarcity of literature comprehensively describing intra-abdominal venous thromboses, and their management. Intra-abdominal venous thromboses include iliocaval venous obstruction (ICVO), hepatic venous thrombosis (HVT), portal venous thrombosis (PVT), renal vein thrombosis (RVT), splenic vein thrombosis (SVT), and gonadal vein thrombosis (GVT); each of which provides unique microenvironmental challenges to management. Doppler ultrasound is the first line imaging modality for diagnosis, and computed tomography and magnetic resonance imaging can help define the extent of thrombus burden and aid with interventional planning. Systemic anticoagulation remains the common medical treatment for intra-abdominal venous thrombosis, however, catheter directed thrombolysis and thrombectomy show positive outcomes in ICVO, HVT, PVT, and RVT, with transjugular intrahepatic portosystemic shunt (TIPS) creation especially beneficial in HVT and PVT. In this review article, we describe pathophysiology, clinical features, imaging findings, and current management options for intra-abdominal venous thromboses.

Navigating Complexities: A Case of Multiple Abdominopelvic Vascular Compression Syndromes in Ehlers-Danlos Syndrome

Abdominopelvic vascular compression syndromes (VCS) refer to conditions where blood vessels in the abdomen or pelvis are compressed by nearby structures, leading to various symptoms and complications. These conditions include superior mesenteric artery syndrome (SMAS), nutcracker syndrome (NCS), May-Thurner syndrome (MTS), and median arcuate ligament syndrome (MALS). Each syndrome is characterized by specific compressions of blood vessels, resulting in symptoms such as pain, nausea, vomiting, weight loss, leg swelling, and other related issues. Ehlers-Danlos syndrome (EDS), characterized by hyperelasticity, altered collagen, and mobility of the viscera, has been associated with VCS, although the exact prevalence is unknown. We report a case of a patient with EDS who presented with multiple VCS, including NCS, MTS, SMAS, and MALS.

Acute left iliofemoral vein thrombosis: Comparison between simple and bony May-Thurner syndrome in CT venography

OBJECTIVES

To explore the etiology of May-Thurner syndrome (MTS) with acute iliofemoral deep vein thrombosis (DVT) regarding imaging findings and clinical features.

METHODS

We retrospectively analyzed 57 patients with acute left iliofemoral DVT from 2015 to 2020. The diameter of left common iliac vein (LCIV) at the maximal compression site and its percent compression regarding the average diameter of the uncompressed iliac vein were recorded in central and distal portions of the LCIV according to the location in the quadrant of lumbar vertebral body. Compression was categorized into simple and bony MTS; Simple MTS as LCIV compressed by the right common iliac artery (RCIA) versus Bony MTS as LCIV by lower lumbar degenerative changes regardless of RCIA compression. Initial computed tomographic venography (CTV) regarding chronic change of LCIV such as fibrotic atrophy or cordlike obliteration, extent of thrombus, and lumbar degenerative changes were evaluated. Therapeutic effect after initial therapy was assessed in follow-up CTVs after 3-6 months.

RESULTS

All patients showed LCIV compression with 19 simple MTS (mean age, 42.8 ± 14.1 years [23-67 years]; 12 females; symptom for 4.4 ± 5.5 days) and 38 bony MTS (mean age, 73.0 ± 10.2 years [49-85 years]; 26 females; symptom for 5.5 ± 4.8 days). There was significant difference in age (p < .001) and no significant difference in sex or symptom duration between two groups (p = .691 and 0.415, respectively). All simple MTS showed compression only in the central LCIV and half of bony MTS showed compression in both central and distal LCIV (p < .001). Among the lumbar degenerative changes, symmetric anterolateral osteophyte (p < .001) and asymmetric osteophyte (p < .001) were significantly associated with bony MTS, but not scoliosis (p = .799), compared to simple MTS. Although there was no significant difference in chronic change of LCIV, thrombosis extent, and therapeutic effect between two groups (p > .05), chronic change of LCIV showed significant difference between single and dual compression (23.7% vs. 57.9%, p = .024) and residual thrombus after initial therapy was occurred in 21.1% of single compression and 47.4% in dual compression with non-significant trend (p = .082).

CONCLUSION

Bony MTS related to lumbar degenerative changes with acute iliofemoral DVT occurs in older patients, presenting more than one stenosis at LCIV, inducing more chronic change with possibly weaker therapeutic effect than simple MTS.

Iliac vein compression syndrome by lumbar degenerative changes is associated with deep vein thrombosis after total knee arthroplasty

INTRODUCTION

This study aimed to identify whether iliac vein compression syndrome(IVCS) is associated with deep vein thrombosis(DVT) after total knee arthroplasty(TKA) and whether lower lumbar degenerative changes were risk factors for IVCS.

MATERIALS AND METHODS

A total of 259 consecutive patients who underwent TKA from January 2019 to March 2022 was retrospectively reviewed. Preoperative plain radiographs of lumbar spines and CT venography (CTV) for DVT diagnosis at postoperative 7 days were performed in all patients. Imaging findings of lower lumbar degenerative changes were analyzed on plain radiograph including lateral osteophytes, scoliosis, lateralolisthesis, retrolisthesis, anterolisthesis, and lower lumbar lordosis angle (LLLA). Percent compression at the left common iliac vein (LCIV) and right common iliac vein (RCIV) as well as DVT were evaluated on CTV. Moreover, IVCS was defined as greater than 50% of compression of the iliac vein on CTV.

RESULTS

DVT occurred in 79 patients (30.5%) after TKA. The overall occurrence of DVT was significantly higher in patients with IVCS of LCIV (52.8%) than those without (18.8%, P < 0.001). When DVT was further subdivided, compared to non-IVCS, IVCS of LCIV was significantly associated with bilateral DVT (P < 0.001, both), especially distal DVT (P < 0.001, both), and IVCS of RCIV was significantly associated with right-side DVT (P = 0.031), especially popliteal (P = 0.008) and distal DVT(P = 0.011). Female patients (OR: 3.945, P = 0.039), presence of left osteophyte (OR: 2.348, P = 0.006), and higher LLLA (OR: 1.082, P < 0.001) were significantly associated with IVCS of LCIV, and presence of right osteophyte (OR: 3.494, P = 0.017) was significantly associated with IVCS of RCIV.

CONCLUSION

IVCS was significantly associated with DVT after TKA and lumbar degenerative changes with lateral osteophytes and hyperlordosis were significant risk factors for IVCS.

CFD Study of the Effect of the Angle Pattern on Iliac Vein Compression Syndrome

Iliac vein compression syndrome (IVCS, or May-Thurner syndrome) occurs due to the compression of the left common iliac vein between the lumbar spine and right common iliac artery. Because most patients with compression are asymptomatic, the syndrome is difficult to diagnose based on the degree of anatomical compression. In this study, we investigated how the tilt angle of the left common iliac vein affects the flow patterns in the compressed blood vessel using three-dimensional computational fluid dynamic (CFD) simulations to determine the flow fields generated after compression sites. A patient-specific iliac venous CFD model was created to verify the boundary conditions and hemodynamic parameter set in this study. Thirty-one patient-specific CFD models with various iliac venous angles were developed using computed tomography (CT) angiograms. The angles between the right or left common iliac vein and inferior vena cava at the confluence level of the common iliac vein were defined as α1 and α2. Flow fields and vortex locations after compression were calculated and compared according to the tilt angle of the veins. Our results showed that α2 affected the incidence of flow field disturbance. At α2 angles greater than 60 degrees, the incidence rate of blood flow disturbance was 90%. In addition, when α2 and α1 + α2 angles were used as indicators, significant differences in tilt angle were found between veins with laminar, transitional, and turbulent flow (p < 0.05). Using this mathematical simulation, we concluded that the tilt angle of the left common iliac vein can be used as an auxiliary indicator to determine IVCS and its severity, and as a reference for clinical decision making.

Management of May Thurner Syndrome in Pregnant Patients

May Thurner Syndrome contributes to thromboembolic disease and can cause significant morbidity in pregnant patients secondary to exaggerated anatomic relationships and physiologic changes in the hematologic system favoring thrombogenesis. Because this condition is both underrecognized and underreported, management in pregnant and postpartum patients is based on expert opinion without any formal evidence-based guidance. Herein, we review five pregnancies in four patients with May Thurner Syndrome and general management strategies. Through collaborative and multidisciplinary care, patients with May Thurner Syndrome can be safely and successfully managed during pregnancy and the postpartum period with appropriate anticoagulation.

Prevalence of left iliac vein compression in an asymptomatic population and patients with left iliofemoral deep vein thrombosis: A multicenter cross-sectional study in southern China

OBJECTIVE

Population-based epidemiological data on left common iliac vein (LCIV) compression is scarce. This study aimed to investigate the prevalence of LCIV compression in an asymptomatic population and patients with left iliofemoral deep vein thrombosis (IF-DVT).

MATERIALS AND METHODS

Nonprobability sampling method was used in this multicenter cross-sectional study. The minimum diameter of LCIV and right common iliac vein minimum were measured. The percentage of LCIV compression (LCIV-CP) was calculated. Compression severity (CS) was classified as mild (CP ≤ 50%), moderate (50% < CP ≤ 70%), and severe (CP > 70%).

RESULTS

In all, 896 subjects constituted the asymptomatic population and 93 patients constituted the IF-DVT population. In the asymptomatic population, LCIV-CP ranged from 1.1% to 89.9% (mean 44.0%), and people with mild, moderate, and severe CS accounted for 62.3%, 28.2%, and 9.5%, respectively. In the IF-DVT population, the mean LCIV-CP was 71.1% (range 42.2%-95.2%), and patients with severe CS accounted for 75.3%. Gender and age differences in LCIV-CP and CS distribution were observed in the asymptomatic population. Females, the young- and middle-aged group had higher LCIV-CPs. In the population with moderate-severe CS, the middle-aged group accounted for a larger proportion. Middle-aged females comprised the highest percentage of patients with moderate or severe CS. Sex and age affected the LCIV-CP and CS distribution. No gender and age differences were observed in the IF-DVT population.

CONCLUSIONS

LCIV compression is common in population. Middle-aged females are the predominant population with moderate-severe compression. Overlapping of LCIV-CP in the asymptomatic and IF-DVT population is significant and other risk factors should be integrated into the consideration when assessing the risk of IF-DVT secondary to LCIV compression.

Diagnostic Value of the Iliac Vein Stenosis Percentage Combined With Indicators of Venous Reflux for Iliac Vein Compression Syndrome With Computed Tomography Venography

OBJECTIVES

To identify a cutoff value of iliac vein stenosis in computed tomography venography (CTV) for assisting in the diagnosis of iliac vein compression syndrome (IVCS). Meanwhile, determining whether the inclusion of venous return and collateral imaging findings could further enhance the diagnostic performance.

METHODS

We conducted a retrospective study on 264 patients suspected of IVCS who underwent both CTV and digital subtraction venography (DSV) from January 2016 to December 2020; they were assigned to either a control group (n = 101) or an IVCS group (n = 163) based on the DSV results. The narrowest anteroposterior diameter of the common iliac vein and the anteroposterior diameter of the distal end were measured to calculate the percentage of iliac vein stenosis. Receiver operating characteristic curve analysis was performed to determine the predictive accuracy of the percentage of iliac vein stenosis for IVCS and whether the inclusion of venous reflux indicators can further improve the diagnostic accuracy.

RESULTS

With respect to the DSV results, the area under the curve was 0.797 (P < 0.001). The best cutoff value was 46.67%, corresponding to a sensitivity of 83.44% and a specificity of 69.31% for predicting IVCS. Moreover, the combination diagnostic method had higher sensitivity and accuracy (94.48% vs 83.44% [P = 0.01] and 84.85% vs 78.03% [P = 0.04], respectively).

CONCLUSIONS

The best cutoff percentage of iliac vein stenosis to diagnose IVCS was 46.67% with CTV. The sensitivity and accuracy of the combined diagnostic method were higher than those of the iliac vein stenosis ratio diagnostic method.

May Thurner syndrome: Sixty years later

May-Thurner syndrome (MTS) was described sixty years ago. Once ignored for several years, it is currently a recognized pathology in the vascular surgery community; but not long ago due to several factors, it was underdiagnosed and sub-optimally treated. In the last 20 years, with renewed interest in venous pathology, technical imaging advances and the recent interventional procedures, it has become a better known disease. On the other hand, nowadays the easiness in diagnosis and treatment of the syndrome has lead to overtreatment of such patients. In this article, we do a historical review and describe the significant advances and current management of May-Thurner syndrome.

Acute deep venous thrombosis induced by May-Thurner syndrome after spondylolisthesis surgery: A case report and review of literature

BACKGROUND

Deep venous thrombosis (DVT) is a serious complication of lumbar spine surgery. Current guidelines recommend pharmacomechanical prophylaxis for patients at high risk of DVT after spine surgery. May-Thurner syndrome (MTS), a venous anatomical variation that may require invasive intervention, is an often overlooked cause of DVT. To date, no case reports of symptomatic MTS caused by isthmic spondylolisthesis or subsequent acute DVT after posterior lumbar surgery have been published.

CASE SUMMARY

We here present a case of a patient who developed acute DVT 4 h after spondylolisthesis surgery, and MTS was only considered after surgery, during a review of a gynecological enhanced computed tomography image taken before the procedure.

CONCLUSION

In conclusion, clinicians should consider MTS in the presence of a dangerous triad: spondylolisthesis, elevated D-dimer levels, and sonographically indicated unilateral deep vein dilation. Consultation with a vascular surgeon is also essential to MTS management.

Non-enhanced multimodal magnetic resonance imaging in assessment of iliac vein obstruction with or without thrombosis

OBJECTIVE

To evaluate the diagnostic accuracy of a contrast-free multimodal magnetic resonance (MR) protocol (including M2DIPEAR, THRIVE, BTFE-SPAIR, and FLAIR sequences) in the detection of iliac vein obstruction with or without thrombosis.

MATERIALS AND METHODS

From May 1st, 2015, to May 1st, 2016, a total of 73 patients (aged 51.33 ± 4.21 years) who received both digital subtraction angiography (DSA) and the multimodal MR imaging were included. The protocol of the multimodal MR included M2DIPEAR and BTFE-SPAIR for presenting iliac vein obstruction, and THRIVE and FLAIR for revealing the co-existed thrombosis. Three observers who were blinded to clinical and DSA results independently analyzed all multimodal MR datasets. Per-patient evaluations on presence or absence of iliac vein obstruction were performed to calculate the diagnostic performance of MR imaging (DSA regarded as gold reference) in terms of overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Capability to display the co-existing venous thrombus was also evaluated per-MR sequence using a 3-point scale system.

RESULTS

Iliac vein obstruction was depicted with DSA in 64 patients. In per-patient evaluation, the multimodal MR imaging yielded accuracy of 95.9% (70/73), sensitivity of 96.9% (62/64), specificity of 88.9% (8/9), positive predictive value of 98.4% (62/63), and negative predictive value of 80% (8/10), respectively. In the multimodal MR sequences, balanced turbo field echo-spectral attenuated inversion recovery (BTFE-SPAIR) sequence was superior to other sequences in depicting the iliac vein configuration, but fluid attenuated inversion recovery (FLAIR) and T1 high-resolution isovolumetric examination (THRIVE) seemed superior in detecting co-existing venous thrombosis.

CONCLUSIONS

M2DIPEAR and BTFE-SPAIR sequence can reveal iliac vein obstruction while THRIVE and FLAIR can detect the co-existed thrombosis. The proposed multimodal MR protocol can accurately depict the iliac vein obstruction and accurately detect the co-existing venous thrombosis comparable with that of DSA.

Comparing the efficacy of endovascular treatment for iliac vein compression syndrome with or without acute deep venous thrombosis: A single-center retrospective study

BACKGROUND

To compare the efficacy of endovascular treatment for iliac vein compression syndrome (IVCS) with or without acute deep venous thrombosis of lower extremity.

METHODS

This study retrospectively analyzed the clinical data of 300 IVCS patients, who received endovascular treatment between January 2013 and December 2017. According to whether IVCS was complicated by deep venous thrombosis or not, these patients were divided into non-thrombotic iliac vein lesion group (NIVL group, n = 127) and post-thrombotic iliac vein lesion group (PIVL group, n = 173). After endovascular treatment, all patients were followed up to assess the symptoms improvement and to evaluate the patency of iliac vein.

RESULTS

The technical success rate was 98% (294/300), and percutaneous transluminal angioplasty with stenting was adopted in 294 cases. The incidence of perioperative complications was 36.33% (109/300), but no severe complications occurred. During a mean follow-up of 22.3 months (range 6-30 months), 9(6.82%, 9/132) patients in PIVL group had recurrence of deep venous thrombosis, but nobody had deep venous thrombosis and varicose veins recurrence in NIVL group. The effective rate of endovascular treatment in NIVL group and PIVL group was 96.88% and 90.15% (P = 0.050), while the cumulative primary patency of iliac vein in NIVL group was significantly higher than that in PIVL group (P = 0.008).

CONCLUSIONS

The endovascular treatment is an effective, feasible, safe method for treating IVCS. There is no difference in the efficacy of IVCS patients with or without deep venous thrombosis, but the medium and long-term patency of patients with deep venous thrombosis is lower than that in patients without deep venous thrombosis.

Novel typing of iliac vein compression in asymptomatic individuals evaluated by contrast enhanced CT

Purpose

Compression of the iliac vein between the iliac artery and lumbosacral vertebra can cause iliac vein compression syndrome (IVCS). The purpose of this study is to assess compression characteristics and establish a new sub-typing in asymptomatic IVCS individuals using contrast-enhanced CT.

Methods

A retrospective analysis of abdomen contrast-enhanced CT images from 195 asymptomatic subjects with iliac vein compressed was investigated. Patients had no history of venous pathology, and images were collected from June 2018 to January 2019. Qualitative and quantitative characteristics of compression were examined including the location, pattern, minor diameter, area, and the percentage compression on an orthogonal section by the post-processing of multiple planar reconstruction and volume rendering.

Results

There were 107 females and 88 males with age range 18–92 years. The most common site of iliac vein compression was localized to the left common iliac vein (LCIV) (178/195, 91.3%). Notably, four compression types (type I–IV) were established according to the compression location, with type II being the most common. The four compression types had differences in the upper limit and fluctuation range of compression. It was found that the average level of iliac vein compression was below 25%. The compression degree of the left common iliac vein in type II was relatively concentrated, and the upper limit of compression was close to 70%.

Conclusion

Asymptomatic iliac vein compression was categorized according to compression location. The proposal of four types might help clinicians to predict which IVCS patients would benefit from interventional therapy.

Prevalence of left iliac vein compression on computed tomography scans from a population

BACKGROUND

May-Thurner syndrome (MTS) is defined as compression of the left iliac vein between the right iliac artery and the lumbar vertebral body in the presence of signs and symptoms of unilateral left chronic venous insufficiency. However, imaging findings of compression are not manifest in symptoms of the syndrome in all subjects.

OBJECTIVES

To evaluate findings of compression in an asymptomatic population.

METHODS

Computed tomography angiographies or venous phase computed tomographies were analyzed. Demographic data and reason for the exam were recorded. Vein diameter was measured at the site of greatest compression and distal of the compression and the ratio between the two diameters was calculated.

RESULTS

From January to July of 2016, 590 computed tomography scans were analyzed (357 women and 233 men). Left iliac compression was found in 14.74% of patients. Patients with a left iliac diameter below the 5mm threshold had a mean diameter at the site of greatest iliac vein compression of 4.4 mm (range: 2.67 mm-4.97 mm). The ratio between the two measurements was < 0.5 in 30% of patients.

CONCLUSIONS

Our study suggests that iliac vein compression is common among random patients who have had computed tomography for any other reason. This indicates that compression found on tomography images is not the only finding to consider when treating a patient.

Compression of left renal vein and left common iliac vein on CT scans: how often are they detected?

Background

The nutcracker and May-Thurner syndromes are rare and, although often underdiagnosed, they can cause limiting symptoms. They are frequently considered only after exclusion of other diagnoses and there is no consensus in the literature on prevalence, incidence, or diagnostic criteria.

Objectives

To estimate the frequency of compression of the left common iliac vein and left renal vein in CT scans of the abdomen and pelvis.

Methods

Descriptive, quantitative, cross-sectional study. The criteria used to define compression of the left renal vein were a hilar/aortomesenteric diameter ratio > 4 and aortomesenteric angle < 39° and the criterion for compression of the left common iliac vein was a diameter < 4mm.

Results

CT scans of 95 patients were analyzed; 61% were women and 39% were men. Left renal vein compression was observed in 24.2% of the sample, with a mean age of 48.8 years, occurring in 27.6% of the women and 18.9% of the men (p = 0.3366). Compression of the left common iliac vein was detected in 15.7% of the sample, with a mean age of 45.9 years, occurring in 24.1% of the women and 2.7% of the men (p = 0.0024). Both veins were compressed in 7.4% of the patients.

Conclusions

Left renal vein compression was detected in women and men at similar frequencies, whereas left common iliac vein compression was more frequent in women. Both venous compressions were most frequently found in patients aged 41 to 50 years.

Lumbosacral exostosis as a rare cause of iliac vein compression and significant limb swelling

A 67-year-old woman presented to our vein clinic for chronic left lower extremity edema, pain, and varicosities. After failed conservative management, a computed tomography scan revealed central venous stenosis secondary to compression of the left common iliac vein by a large osteophyte along the anterolateral aspect of the L5-S1 disk space. An anterior osteophytectomy was performed, followed by iliac venous stenting at a 1-month interval. The patient had resolution of symptoms and remains symptom free at 15 months of follow-up. This report describes a spinal exostosis causing symptomatic venous compression successfully relieved by surgical decompression.

A case report of May-Thurner syndrome induced by anterior lumbar disc herniation: Novel treatment with radiofrequency thermocoagulation

RATIONALE

Lumbar degeneration-related May-Thurner syndrome (dMTS) is characterized by venous compression induced by degenerated lower lumbar structures. Treatment strategies for May-Thurner syndrome (MTS) include clearing the thrombus and correcting venous compression. Despite having different etiological factors from other MTS types, treatments for dMTS are similar, including endovascular angioplasty and continuous anticoagulation therapies. Thus, a particular treatment was designed herein to focus on compressive lumbar structures instead of intravenous management.

PATIENT CONCERNS

A 59-year-old female patient with dMTS, which was induced by inferior vena cava (IVC) stenosis compressed by L4-5 anterior disc herniation.

DIAGNOSIS

The patient was diagnosed with IVC stenosis and L4-5 lumbar disc herniation based on abdominal computed tomography, ultrasound, and lumbar magnetic resonance imaging findings.

INTERVENTIONS

Radiofrequency thermocoagulation (RF) was applied to the patient to decrease the compression caused by anterior disc herniation.

OUTCOMES

After surgery, the patient's swelling started to improve within 5 hours and completely diminished after 48 hours. Postsurgical abdominal ultrasound showed that her IVC patency increased by 20%. On follow-up, her leg symptoms did not recur at 12 months after surgery.

LESSONS

We provided a novel idea in the treatment of dMTS, in which we shifted the treatment focus from endovascular patency restoration to extravascular decompression. Our case proved that RF was effective in treating dMTS, which is a complementary treatment modality to angioplasty.

Strategies for the diagnosis and treatment of the iliac vein compression syndrome

AIM

To evaluate the diagnosis and treatment strategies for the iliac vein compression syndrome (IVCS) and the factors that affect the treatment outcome.

METHODS

In total, 69 patients with IVCS were enrolled in the study. The patients underwent computed tomography (CT) venography before treatment. CT observations included assessment of the iliac venous channel sagittal diameter (IVCD) before the lower lumbar vertebra, causes of oppression, thrombus density, and embolization range. The patients with IVCS were divided into the simple IVCS (sIVCS, n = 22), lumbar degeneration-related type IVCS (dIVCS, n = 33), and IVCS of other causes (oIVCS, n = 14) including lumbar fracture, hematoma of infection, and abscess wraping around and compressing the iliac vein, groups. The treatment methods included target venous catheter-directed thrombolysis (CDT), a mechanical breaking and sucking treatment for the thrombi, followed by balloon dilatation and iliac vein stent implantation. The factors that may possibly affect the treatment outcomes included IVCS type, duration of disease, thrombus hardness, embolization length, and treatment regimen. Logistic regression was used to analyze the factors that affected the therapeutic efficacy.

RESULTS

At the first stage, CDT was only effective in 15 cases (5 dIVCSs and 10 oIVCSs) and was ineffective in the remaining 54 cases, which required further mechanical breaking and sucking of the thrombi and intravenous balloon dilatation. In the second stage, combination of thrombi breaking and suction and balloon dilatation was preliminarily effective in 26 cases (6 sIVCSs, 16 dIVCSs and 4 oIVCSs), but during follow-up from 1 to 6 months, treatment was considered futile for 9 recurrent cases (3 sIVCSs and 6 dIVCSs). So, 28 cases of preliminary ineffective treatment and 9 relapse in the second stage were arranged to the third stage of treatment by iliac vein stent implantation. All 37 cases were treated effectively and achieved a satisfactory iliac vein patency, and were followed-up for 24 months without recurrence. Logistic regression analysis showed that IVCS type (β = 4.14; Wald test, P < 0.01), duration of illness (β = -5.33; Wald test, P = 0.02), thrombus density (β = -6.46; Wald test, P = 0.01), embolization length (β = 2.74; Wald test, P = 0.03), and treatment regimens (β = 11.92; Wald test, P = 0.01) all had a significant effect on the treatment outcomes.

CONCLUSION

The selection of a suitable intervention treatment regimen for different types of IVCS may aid in improving the curative effect.

Left iliac vein compression is not associated with infrainguinal deep venous thrombosis but is associated with iliac vein involvement

OBJECTIVE

The purpose of this study was to investigate whether left iliac vein (LIV) compression had similar correlation with the risk of left iliac deep venous thrombosis (DVT; iliac vein involvement) and infrainguinal DVT (without iliac vein involvement).

METHODS

A retrospective analysis of records and enhanced computed tomography images was conducted of 278 patients with left-sided DVT (iliac DVT, 228 patients; infrainguinal DVT, 50 patients) and 232 control patients without DVT on either side. The influences of LIV compression on the risk of left iliac DVT and infrainguinal DVT were investigated using logistic regression analysis.

RESULTS

Mean percentage compression of the LIV in left iliac DVT (74.64% ± 0.99%) patients was significantly higher than in non-DVT patients (53.42% ± 1.49%; P < .01). However, mean percentage compression of the LIV in left infrainguinal DVT patients (45.37% ± 2.71%) was significantly lower than in non-DVT patients (53.42% ± 1.49%; P < .01). LIV compression was associated with increased odds of left iliac DVT (odds ratio, 1.88; 95% confidence interval, 1.64-2.15; P < .01) for each 10% increase in percentage compression of the LIV. However, LIV compression was not associated with increased odds of infrainguinal DVT (odds ratio, 0.89; 95% confidence interval, 0.76-1.03; P = .126).

CONCLUSIONS

Left iliac DVT patients had more severe LIV compression than left infrainguinal DVT patients did. LIV compression was not associated with development of left infrainguinal DVT, but it did correlate with the presence of left-sided DVT with iliac vein involvement.

Late-Onset Nonthrombotic Left Common Iliac Vein Compression Secondary to Degenerative Lumbar Disc: A Case Report of May-Thurner Variant

May-Thurner syndrome (MTS) refers to venous outflow obstruction caused by extrinsic compression of the left common iliac vein (LCIV) by the overlying pulsatile right common iliac artery against lumbar vertebrae. The classic clinical presentation is acute unilateral left leg painful swelling due to deep venous thrombosis in a young woman in the second or third decade of life. We present a case of a 66-year-old woman who presented with late-onset left leg swelling caused by nonthrombotic venous hypertension due to degenerative lumbar disc bulge leading to LCIV compression against the left common iliac artery which was confirmed by computed tomography and intravascular ultrasound. Our case highlights the importance of high index of suspicion for MTS in elderly patients with unilateral leg swelling and the importance of multimodality imaging for understanding the mechanism and appropriate treatment of MTS.

A Rare Presentation of an Isolated Internal Iliac Artery Aneurysm: Report of a Case and Literature Review

Isolated internal iliac artery aneurysms (IIIAAs) are extremely rare. We present the case of a 75-year-old white Caucasian male patient admitted for right lower limb deep venous thrombosis and low-risk pulmonary embolism due to the compression of the external iliac vein from an IIIAA. A review of the literature was also performed to identify the epidemiologic, clinical characteristics and diagnostic and operative strategies of this disease. At present, a recommendation for the best operative strategy in the presence of an IIIAA is difficult. Our analysis demonstrated controversial results, but we are confident to recommend the endovascular treatment in an elective setting.