A Comprehensive Review of the Pathophysiology and Clinical Importance of Iliac Vein Obstruction

A comprehensive ultrasound approach to lower limb varicose veins and abdominal-pelvic connections

OBJECTIVE

Pelvic venous reflux may be responsible for pelvic venous disorders and/or lower-limb (LL) varicose veins. Ultrasound investigation with Doppler allows a complete study of the entire infra-diaphragmatic venous reservoir. The aim of this study was to guide and standardize the investigation of the pelvic origin of venous reflux in female patients with LL varicose veins.

METHODS

In this case-control study, we applied a comprehensive ultrasound investigation protocol, which involved four steps: (1) venous mapping of the lower limbs; (2) transperineal and vulvar approach; (3) transabdominal approach; and (4) transvaginal approach.

RESULTS

Forty-four patients in group 1 (patients with LL varicose veins and pelvic escape points [PEPs]) and 35 patients in group 2 (patients with LL varicose veins without PEPs [control group]) were studied, matched by age. The median age was 43 years in both groups. The calculated body mass index was lower in group 1 (23.4 kg/m2) compared with the control group (25.4 kg/m2), and this difference reached statistical significance (P < .001). The presence of pelvic varicose veins (PVs) by transvaginal ultrasound was 86% in group 1 and 31% in group 2. Perineal PEPs were the most prevalent, being found in 35 patients (79.5%), more frequent on the right (57.14%) than on the left (42.85%) and associated with bilateral PVs 65.7% of the time. In group 1, 23 patients (52%) reported recurrent varicose veins vs eight patients (23%) in the control group (P = .008). Regarding the complaint of dyspareunia, a significant difference was identified between the groups (P = .019), being reported in 10 (23%) patients in group 1 vs one patient (2.9%) in the control group. The median diameters in the transabdominal approach of the left gonadal veins were 6.70 mm for group 1 and 4.60 mm for group 2 (P < .001). In patients with PVs in group 1, the median diameter of PEPs at the trans-perineal window was 4.05 mm. In the transvaginal examination, the mean diameter of the veins in the peri uterine region was 8.71 mm on the left and 7.04 mm on the right.

CONCLUSIONS

The identification of PEPs by venous mapping demonstrates the pelvic origin of the reflux and its connections with the LL varicose veins. For a more adequate treatment plan, we suggest a complete investigation protocol based on the transabdominal and transvaginal study to rule out venous obstructions, thrombotic or not, and confirm the presence of varicose veins in the pelvic adnexal region.

Mechanism of effect of stenting on hemodynamics at iliac vein bifurcation

When performing stent intervention for iliac vein compression syndrome, the operator selects the appropriate stent and determines its implantation depth according to the type and severity of iliac vein stenosis in the patient. However, there is still uncertainty regarding how the structure of the stent and its implantation depth affect hemodynamics at the site of lesion. In this paper, we analyzed three commonly used stents (Vena stent from Venmedtch, Venovo from Bard, and Smart stent from Cordis) with different implantation depths (0, 10, 20 mm) using computational fluid dynamics (CFD). We focused on evaluating hemorheological parameters such as time-averaged wall shear stress (TAWSS), oscillatory shear index (OSI), etc., within one pulsatile cycle after stent implantation. The correlation between geometric parameters of the stents and hemodynamic indicators was assessed using Pearson correlation coefficient (r), which was further validated through PIV velocity measurement experiment. The results revealed that an increase in implantation depth led to a more pronounced disturbance effect on blood flow at bifurcation for densely arranged support body-type stents. This effect was particularly significant during periods of smooth blood flow. On the other hand, crown-shaped Vena stents exhibited relatively less disruption to blood flow post-implantation. Implantation depth showed a strong negative correlation with TAWSS but a strong positive correlation with OSI and RRT. These findings suggest an increased risk of thrombosis at iliac vein bifurcation following stent placement. Amongst all three tested stents, Vena Stent demonstrated more favorable periodic parameters after implantation compared to others. These results provide valuable theoretical insights into understanding contralateral circulation thrombosis associated with iliac vein stenting.

Prevalence and predictors of radiological left common iliac vein compression in asymptomatic patients

OBJECTIVE

The aim of this study was to investigate the prevalence of radiological left common iliac vein (LCIV) compression among the asymptomatic population and identify possible predictors.

METHODS

Contrast-enhanced abdominal and/or pelvic computed tomography scans of eligible asymptomatic patients were examined. The LCIV diameter was measured from different horizontal planes in the venous phase using PACSView. Degree of LCIV compression (Dc) was calculated by a predefined formula and graded as insignificant (Dc < 25%), mild (≥25% Dc < 50%), moderate (≥50% Dc <75%), and severe (Dc ≥ 75%). Venous stenosis was defined as a Dc of ≥50%. Comparison of variables, including gender, age, body mass index (BMI), and comorbidities was performed between the different grades of LCIV compression.

RESULTS

Between November 2019 and July 2022, 1698 eligible asymptomatic patients (53.1% females; mean age, 39.3 ± 11.8 years; mean BMI, 22.9 ± 3.6 kg/m2) were reviewed. The mean Dc was 46.2% (range, 0.29%-90.4%). Insignificant, mild, moderate, and severe compression were distributed in 14.5%, 38.0%, 42.2%, and 5.2% of the cohort population, respectively. Prevalence of venous stenosis was higher in females than males (58.1% vs 42.2%; χ2 = 15.52; P < .001). Females aged ≥25 and <35 years accounted for the highest proportion of venous stenosis than other age groups and was a significant predictor (odds ratio [OR], 3.18; 95% confidence interval [CI], 1.74-7.79; P < .001). In the Asian BMI classification group, being underweight is associated with venous stenosis (OR, 4.69; 95% CI, 2.70-8.14; P < .001) and obesity may be a protective factor (OR, 0.38; 95% CI, 0.23-0.64; P < .001). There is an inverse relationship between Dc and age and BMI.

CONCLUSIONS

The prevalence of radiological LCIV compression on computed tomography scans was high, but all patients were asymptomatic. Female gender, especially those aged ≥25 and <35 years, and underweight were possible predictors for venous stenosis.

Association between the degree of iliac venous outflow obstruction by intravascular ultrasound and lower limb venous reflux

OBJECTIVE

The present study aims to evaluate the association between the degree of iliac venous outflow obstruction (IVOO) identified by intravascular ultrasound (IVUS) and venous reflux presentation in the lower limbs on duplex ultrasound (DU).

METHODS

Patients with bilateral chronic venous insufficiency, CEAP (clinical-etiology-anatomy-pathophysiology) C3 to C6, and a visual analog scale score for pain >5 underwent DU for reflux evaluation of the deep venous system (reflux ≥1 second); superficial system, great saphenous vein, and small saphenous vein (reflux ≥0.5 second); and perforator system (reflux ≥0.35 second). All patients underwent IVUS in the iliac venous territory. The area of the impaired venous segments was categorized as obstruction <50% (category 1), 50% to 79% (category 2), and ≥80% (category 3). The venous clinical severity score and reflux multisegment score (RMS) were assessed.

RESULTS

A total of 51 patients (n = 102 limbs; age, 50.53 ± 14.5 years; 6 men) were included. The predominant clinical severity CEAP class was C3 in 54 of 102 limbs (52.9%). The mean VCSS was 14.3 ± 6.7. A severe RMS (≥3) was registered in 63.4% of the limbs. Of the 102 limbs, 51 (50%) presented with category 1, 27 (26.5%) with category 2, and 24 (23.5%) with category 3. Previous deep vein thrombosis (DVT) was associated with critical obstruction (odds ratio [OR], 3.65; 95% confidence interval [CI], 1.29-10.38; P = .015). The superficial and perforator venous systems had no association with the degree of IVOO. Deep venous reflux (DVR) had a significant association with significant IVOO (obstruction ≥50%; OR, 6.44; 95% CI, 2.19-18.93; P = .001) and critical IVOO (obstruction ≥80%; OR, 4.57; 95% CI, 1.70-12.27; P = .003) and a significant linear association with the IVOO degree and reflux in the femoral veins (P < .001) and popliteal vein (P = .008). Significant lesions were significantly more likely to develop in the left limb (OR, 5.76; 95% CI, 2.46-13.50; P < .001). After multivariate analysis, DVR remained a predictor for significant and critical obstruction (P < .003 and P < .012, respectively). Left limb and previous DVT remained as predictors for IVOO of ≥50% and ≥80% (P < .001 and P = .043, respectively).

CONCLUSIONS

We found a significant linear association between the degree of IVOO and reflux in the deep venous system on DU. Limbs with DVR, a severe RMS, loss of respiratory variation on DU, and previous DVT were more likely to be affected by IVOO of ≥50%, especially with left leg involvement.

Impact of Common Iliac Vein Compression on the Incidence of Pulmonary Embolism in Patients with Acute Deep Vein Thrombosis

OBJECTIVE

This study aimed to investigate the association between common iliac vein (CIV) compression and pulmonary embolism (PE) in lower extremity deep vein thrombosis (DVT).

METHODS

This was a single centre retrospective study. Between January 2016 and December 2021, DVT patients with enhanced computed tomography of the iliac vein and pulmonary artery were included. Patient demographics, comorbidities, risk factors, and degree of CIV compression were collected and analysed. Logistic regression was performed to evaluate the odds ratio (OR) with a 95% confidence interval (CI) of PE in relation to compression severity groups. The association between PE and compression degree was evaluated with restricted cubic splines (RCS) based on an adjusted logistic regression model.

RESULTS

Two hundred and twenty-six DVT patients (left side, n = 153; right side, n = 73) were included. Univariable analyses suggested that symptomatic or asymptomatic PE (54.4%, 123/226) was more common in men (p = .048) and right side DVT (p = .046) patients. Compared with no CIV compression, multivariable analyses suggested that mild compression did not statistically significantly reduce the PE risk, whereas moderate (adjusted OR 0.36; 95% CI 0.15 - 0.88; p = .025) and severe (adjusted OR 0.18; 95% CI 0.06 - 0.54; p = .002) compression statistically significantly reduced the risk. RCS showed that a smaller minimum diameter or greater compression percentage was correlated with continuously decreasing PE risk at a minimum diameter of < 6.77 mm or compression > 42.9%.

CONCLUSION

PE is more common in men and right side DVT patients. An increasing severity of CIV compression is consistently associated with a decreasing risk of PE when the minimum diameter is < 6.77 mm or the compression is > 42.9%, indicating that it is a protective factor against PE.

The association between iliac vein compression degree and characteristics of first diagnosed left lower extremity deep vein thrombosis

Objective

This study aimed to investigate the association between the left common iliac vein (CIV) compression degree and characteristics of first diagnosed left lower extremity deep vein thrombosis (DVT).

Patients and methods

This was a single-center retrospective observational study. Between January 2015 and June 2022, first diagnosed left lower extremity DVT patients with enhanced computed tomography of lower extremities were included. Patient demographics, comorbidities, risk factors, DVT characteristics, and CIV compression degree were collected and analyzed. Logistic regressions were performed to evaluate the odds ratio (OR) with a 95% confidence interval (CI) of iliofemoral or mixed DVT vs. compression percentage. The association between compression percentage and iliofemoral or mixed DVT was evaluated on a continuous scale with restricted cubic splines (RCS). The association between compression percentage and thrombus burden was evaluated using the Spearman test.

Results

A total of 196 (mean age, 61.8 ± 16.1 years; 86 males) patients were included. The median CIV compression percentage in iliofemoral or mixed DVT patients was significantly greater than in non-iliofemoral or non-mixed DVT, respectively (64.4 vs. 46.6%, p < 0.001; 67.8 vs. 54.8%, p = 0.004). CIV compression >50% was associated with significantly increased morbidity of iliofemoral DVT (adjusted OR, 2.96; 95% CI, 1.58-5.52; p = 0.001) or mixed DVT (adjusted OR, 2.39; 95% CI, 1.19-4.81; p = 0.014). RCS showed that a greater compression percentage was associated with a continuously increased OR of iliofemoral DVT (overall p = 0.003, non-linear p = 0.577) or mixed DVT (overall p = 0.020, non-linear p = 0.771). CIV compression percentage had a positive correlation with thrombus burden (rs = 0.284, p < 0.001).

Conclusion

A greater left CIV compression percentage may be associated with increasing likelihood of more proximal location and severe clot extent in first diagnosed left lower extremity DVT.

Midterm and Long-Term Outcomes following Dedicated Endovenous Nitinol Stent Placement for Symptomatic Iliofemoral Venous Obstruction: Three- to 5-Year Results of the VIRTUS Study

PURPOSE

To assess the midterm patency and long-term safety of placement of a dedicated venous stent (Vici Venous Stent System) for the treatment of venous lesions of the iliofemoral outflow tract.

MATERIALS AND METHODS

Patients with unilateral obstructive disease of the iliofemoral veins and a Clinical, Etiological, Anatomical, Pathophysiological class of 3 or higher or a Venous Clinical Severity Score of 2 or greater were enrolled in this prospective, multicenter, single-arm study at 23 sites in the United States and Europe. The patients were followed up for 36 months after the index procedure for the assessment of patency and up to 60 months for the assessment of safety. The clinical outcomes in 11 patients with a stent fracture were assessed.

RESULTS

A total of 200 patients enrolled in 2 cohorts (ie, feasibility cohort, n = 30; pivotal cohort, n = 170) were combined for this analysis. The overall 36-month primary patency rate was 71.7% (86/120), and the 36-month primary patency rate was 96.4% (27/28) for the nonthrombotic group and 64.1% (59/92) for the postthrombotic group. The freedom from major adverse events was 81.2% (53/65) through 60 months. The 60-month Kaplan-Meier estimate of freedom from target vessel revascularization (TVR) was 84.3%. In 9 of the 11 patients who had a stent fracture (1 patient with nonthrombotic etiology and 10 patients with postthrombotic etiology) identified at 12 months, the stents extended into the common femoral vein. The TVR rates and clinical outcomes were similar between patients with and without a stent fracture.

CONCLUSIONS

The results of the VIRTUS study demonstrated good midterm patency and long-term safety following the placement of a dedicated venous stent for iliofemoral obstruction.

Imaging Signs of May-Thurner Syndrome in Asymptomatic Patients: Computed Tomography Angiography Analysis of Kidney Donors1

OBJECTIVE

The current study aimed to evaluate the distance between the right common iliac artery (RCIA) and lumbar vertebra in asymptomatic patients in order to determine whether such distance was statistically correlated with the left common iliac vein (LCIV) diameter (LCIVD) and to investigate if both measures were related to demographic characteristics and anthropometric data, such as sex, age, height, and body mass index (BMI).

METHODS

In this descriptive and uncontrolled anatomic study, data from high-definition computed tomography (CT) angiography images of living kidney donors without a medical history of chronic venous insufficiency or past deep vein thrombosis (DVT) were analyzed. The RCIA crossed over the LCIV in 311 individuals, who were then included in this study. CT scans were reviewed to measure (1) the narrowest space between the RCIA and fifth lumbar vertebral body and (2) the LCIVD. Measures were subjected to normality tests and were divided according to the sex of the study population. Correlations of measures with age, BMI, and height were calculated.

RESULTS

Of the 311 patients analyzed, 66.6% (n = 207) were female. The mean lumbar vertebral body-iliac artery distance (LVBIAD) was 7.2 mm, whereas the mean LCIVD was 8.5 mm; both were higher in men (P < .001). The statistical analysis of LVBIAD and LCIVD distributions revealed no normality pattern (P < .05). The analysis of the correlation between them showed a weak statistically significant relationship with age. A linear regression model considering the normality percentile interval indicated a strong positive correlation between LVBIAD and LCIVD (R² = .884).

CONCLUSIONS

The LVBIAD was <5 mm and <3 mm in 25% and 5% of asymptomatic individuals, respectively. The LCIVD correlated with the space between the RCIA and lumbar vertebra. The distance between the RCIA and lumbar vertebra and the LCIVD were higher in male subjects and older patients, but did not correlate with BMI and height.

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.

The Clinical Problem of Pelvic Venous Disorders

Pelvic venous disorders are inter-related pathologic conditions caused by reflux and obstruction in the pelvic veins. It can present a spectrum of clinical features based on the route of transmission of venous hypertension to either distal or caudal venous reservoirs. Imaging can help to visualize pelvic vascular and visceral structures to rule out other gynecologic, gastrointestinal, and urologic diseases. Endovascular treatment, owing to its low invasive nature and high success rate, has become the mainstay in the management of pelvic venous disorders. This article reviews the pathophysiology, clinical presentations, and diagnostic and therapeutic approaches to pelvic venous disorders.

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.

Editor's Choice - Clinical Efficacy of Venastent - A Novel Iliac Vein Stent for Non-Thrombotic Iliac Vein Lesions: A Multi-Centre Randomised Controlled Trial

OBJECTIVE

To determine the efficacy of Venastent - a novel iliac vein stent for non-thrombotic iliac vein lesions (NIVLs).

METHODS

From October 2018 to January 2021, 256 NIVL patients were recruited at 19 Chinese hospitals. A randomised controlled trial was conducted to compare the efficacy of the new iliac vein stent-Venastent (Tianhong China) with Zilver stent (Cook USA). All patients were allocated randomly to two groups: the experimental group patients used Venastent, while the control group received the Zilver stent. The trial was registered in Chinese Clinical Trial Registry (ChiCTR2200057851).

RESULTS

A total of 123 patients in the experimental group and 122 patients in the control group had a full set of data collected (p = ns). The technical success rate was 100% (n = 245/245). The patency rate was 100% (n = 123/123) in the experimental group and 98.4% (n = 120/122) in control group one year after operation (p = ns). The lower extremity swelling remission rate was 79.1% (n = 87/110) in the experimental group and 78.4% (n = 91/116) in the control group (p = ns). The lower extremity pain relief rate was 68.8% (n = 50/80) in the experimental group and 77.2% (n = 71/92) in the control group (p = ns). The ulcer healing rate was 90% (n = 18/20) in the experimental group and 87% (n = 20/23) in the control group (p = ns). There was no difference in stent re-stenosis or clinical remission between the two groups.

CONCLUSION

The new iliac vein stent, Venastent, had a comparable high patency rate and safety profile as the Zilver stent (Cook) in NIVLs patients. Venastent significantly reduced symptoms of chronic venous disease.

Pivotal Study Evaluating the Safety and Effectiveness of the Abre Venous Self-Expanding Stent System in Patients With Symptomatic Iliofemoral Venous Outflow Obstruction

Supplemental Digital Content is available in the text.

Background:

Iliofemoral venous obstruction is recognized with increasing frequency as the underlying cause of lower extremity symptoms including edema, pain, skin changes, and, in advanced cases, ulceration. This study sought to evaluate the safety and effectiveness of the Abre venous self-expanding stent system for the treatment of symptomatic iliofemoral venous outflow obstruction.

Methods:

The ABRE Study (A Multi-Center, Non-Randomized Study to Evaluate the Safety and Effectiveness of the Abre Venous Self-Expanding Stent System in Patients With Symptomatic Iliofemoral Venous Outflow Obstruction) is a single-arm, multicenter, prospective study that included 200 subjects from 24 global sites. The primary end points were 12-month primary patency and major adverse events within 30 days. Secondary end points included lesion and procedure success, primary-assisted and secondary patency, major adverse events, stent migration, stent fracture, and quality of life changes. End point-related adverse events and imaging studies were adjudicated by independent clinical events committee and core laboratories, respectively.

Results:

Venous obstruction cause was classified as acute deep vein thrombosis (16.5%, 33/200), post-thrombotic syndrome (47.5%, 95/200), or nonthrombotic iliac vein lesion (36.0%, 72/200). The common iliac and external iliac veins were stented in 96.0% (192/200), 80.5% (161/200) of subjects, respectively. Stent implant into the common femoral vein was required in 44.0% (88/200). Primary patency at 12 months was 88.0% (162/184). Four (2.0%) major adverse events occurred within 30 days. Twelve-month primary-assisted and secondary patency were 91.8% (169/184) and 92.9% (171/184), respectively. No stent fractures or migrations were reported. Mean target limb Villalta score decreased from 11.2±5.6 at baseline to 4.1±4.8 at 12 months, and the mean target limb revised Venous Clinical Severity Score decreased from 8.8±4.7 at baseline to 4.3±3.6 at 12 months. Clinically meaningful improvements in quality of life and venous functional assessment scores from baseline were demonstrated through 12 months in all measures.

Conclusions:

Symptomatic iliofemoral venous obstruction can be successfully treated with an Abre venous stent. Study outcomes demonstrated a high patency rate with a good safety profile. Patients demonstrated a significant reduction in clinical symptoms and improvement in quality of life that was maintained through 12-month follow-up.

Registration:

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03038438.

Left common iliac vein compression identified by vascular ultrasonography in asymptomatic women: does standing position influence diagnosis?

Background

Vascular ultrasonography is the imaging exam of choice for initial screening for left common iliac vein compression, which is an asymptomatic finding that can be detected in up to 25% of some patient samples.

Objective

To determine, using vascular ultrasonography, whether findings of left common iliac vein compression in asymptomatic women are different when assessed in the prone and standing positions.

Methods

This is a cross-sectional observational study of 50 adult female volunteers with no symptoms of pelvic venous compression. The parameters assessed with vascular ultrasonography in the prone and standing positions were diameters and maximum velocities of the left common iliac vein at the point at which it crosses behind the right common iliac artery and before this point, in addition to left common iliac vein velocity indices at the crossing.

Results

Eight cases of significant compression of the left common iliac vein were identified when assessed in prone position (16%) and just two cases (4%) were identified in the standing position. Left common iliac vein diameters were statistically larger (p = 0.002) at the point where it crosses behind the right common iliac artery in the standing position and velocities and velocity indices were statistically higher (p < 0.001) in the prone position. No significant compression of the left common iliac vein was identified in the standing position when velocity indices were normal in the prone position.

Conclusions

There was no difference in detection of significant compression of the left common iliac vein when assessed in the standing position in comparison with assessment in the prone position. However, the study showed that anatomic compression of the left common iliac vein may be reduced in the standing position.

Choosing the Most Appropriate Treatment Option for Pelvic Venous Disease: Stenting versus Embolization

Pelvic venous disease (PeVD) in women encompasses a wide variety of entities all resulting in pelvic pain and varices. Successful treatment with percutaneous interventions is dependent on identifying underlying factors contributing to the disease and addressing them with either embolization of incompetent veins or stenting for venous stenoses. There are a multitude of embolization methods with marked practice heterogeneity. Moreover, with the ongoing development of dedicated venous stents in the treatment of chronic venous disease, there are more opportunities to consider this modality for the treatment of PeVD, as many patients present with combined vein reflux and central venous stenosis. The necessity to address both and the order of interventions in these patients is still to be elucidated. Here, we describe when to choose stenting or embolization for PeVD, their limitations, and our practice and identify further areas of research in this field.

Contemporary treatment of May-Thurner Syndrome

Compression of the left common iliac vein by the overlying right common iliac artery is a benign anatomic abnormality in most individuals. However, in patients with significant vein compression, outflow obstruction and chronic intraluminal venous damage may lead to May-Thurner Syndrome. This syndrome commonly manifests as unilateral left leg swelling or acute iliofemoral deep venous thrombosis. In addition to clinical findings, diagnosis is made with ultrasound, computed tomography venography, or magnetic resonance venography. The extent of compression of the iliac vein is best determined by venography with intravascular ultrasound. Symptoms and hemodynamic significance of the compression guides the ideal treatment approach. Iliocaval stenting has become the standard treatment for this condition and has promising patency rates and clinical outcomes. This review paper provides an overview of pathophysiology, and utility and limitations of the existing diagnostic modalities and treatment options in the management of May-Thurner Syndrome.

Iliac Vein Stenosis: Is the Data Strong Enough for Stenting in the Young Pelvic Venous Disorders (PeVD) Population?

Iliac vein stenosis is a clinical condition resulting from external compression of the iliocaval venous unit with the consequent remodeling of the vascular wall, hemodynamic alterations, and predisposition to venous thrombosis. As such, the most common indications for percutaneous endovascular iliac vein stenting supported by the literature, include the management of thrombotic and non-thrombotic iliac venous lesions associated with advanced chronic venous disease (CVD). However, its clinical presentation is variable, and it may also include features associated with PeVD such as chronic pelvic pain, perineal heaviness, urinary urgency, postcoital pain, and vulvar or superficial non-saphenous veins varicosities. In this setting, the management revolves around the relieving venous obstruction and restoring normal blood flow through the compressed vein with percutaneous endovascular iliac vein stenting, that can be augmented with ovarian vein embolization (OVE) or direct embolization of the superficial varices. Given the heterogeneity of PeVD presentation and the lack of high-level quality data in outcomes for iliac vein stenosis stenting, this review will discuss the current evidence available for this intervention and clinical issues to consider when evaluating these patients.

Endovascular versus medical treatment of venous compression syndrome of the iliac vein - a systematic review

The treatment of non-thrombotic iliac vein lesions (NIVL) remains debatable with many advocating conservative treatments, whilst others offering venous stenting. The objective of this review was to systematically assess the treatment options for symptomatic iliac vein compression syndrome (IVCS) in patients without evidence of thrombotic disease at the time of diagnosis. An online search of published literature looking for randomised controlled trials and observational studies that evaluated the treatment for symptomatic NIVL was performed. Nine studies were included with a total 953 patients of which 782 patients had NIVL. Patency rates ranged between 94.8%-100% in the first month, 88.2%-94.1% in six months and 73.4%-98% in 12 months, in patients with NIVL post stenting. Longer follow-up of up to 5 years shows promising patency rates of 94% in patients with IVCS. Patients with IVCS are likely to benefit from a combination of endovenous treatment at the time of diagnosis including stent placement to maintain lumen patency and prevent recurrent deep venpus thrombosis and/or postthrombotic syndrome.

Atypical May-Thurner syndrome caused by endovascular aortic aneurysm repair

May-Thurner syndrome is characterized by unilateral lower extremity venous hypertension and stasis due to compression of an iliac vein between an iliac artery and the lumbar spine. In almost all cases, the left common iliac vein is compressed by the right common iliac artery; however, other patterns have been described. Rarely, May-Thurner syndrome may be created iatrogenically as a result of iliac artery stenting. We present an unusual case of new left common iliac vein thrombosis caused by ipsilateral left iliac artery compression after aortobi-iliac endovascular aneurysm repair.