Frequency of left common iliac vein compression in asymptomatic adolescents and young adults.

Introduction: May-Thurner Syndrome (MTS) is a condition in which the left common iliac vein is compressed by the right common iliac artery, which together with intraluminal vein changes can lead to clinically symptomatic venous outflow obstruction. Patients having such pathology may suffer from symptoms of venous hypertension as well as lower leg deep venous thrombosis. In most of the MTS cases, static and continuous compression is observed which can also lead to the intraluminal spur formation. According to the literature, among the factors which can influence the severity of iliac vein compression, lumbar spinal degeneration can also be mentioned. Considering the aortic bifurcation anatomical conditions, also other, non — degenerative changes of the lumbar vertebral column segment can be taken into consideration. Aim: This study aimed to reveal the prevalence of the left common iliac vein compression in young healthy individuals as well as to assess the severity of the left iliac vein compression provoked by lumbar hyperlordosis. Material and methods: The study was performed on a group of 207 volunteers of both sexes, aged 21–27 yrs. using ultrasound examination to measure the diameter of the right common iliac vein as well as the diameter of the left common iliac vein in the area of the possible compression by the right iliac artery. In all the patients the measurements were performed in the supine position as well as in the provoked lumbar hyperlordosis position. In all the individuals the presence of the symptoms and signs of the lower leg chronic venous disease were investigated. Results: The mean anterior-posterior diameter of the right common iliac vein in the standard supine position in the whole study group was 5.71 mm (± 0.6 mm). The mean diameter of the left common iliac vein in a normal horizontal position was 4.87 mm (± 0.6 mm) with a range from 3.8 mm to 6.2 mm. In most of the cases, the difference between the left and iliac common vein diameter (when measured in the place of the right iliac artery crossing) did not exceed 20%. In 15.9% of the study subjects, the right and left iliac vein diameter difference ranges between 20–30% and in 2.41% only, the diameter difference over 30% was noticed (in none of the cases the stenosis exceeding 40% of the vein diameter was found). Looking for the effect of the overlordosis on the proclivity to decrease left iliac vein diameter, in the provoked hyperlordosis position the changes of the iliac vein diameter in the range of 21–30% were observed in 15.9% and over 30% in 2.4% of the study subjects. Hyperlordosis presence was also responsible for the shift towards lower left iliac vein diameter — in 36.2% of the patients, the left iliac vein diameter below 4 mm was noticed including 1.9% of individuals with a diameter not exceeding 3 mm. In the analysis, there was no statistically significant correlation between the presence of the reported CVD symptoms in the left leg and the reported diameter reduction between the right and left iliac veins in the population of the studied young individuals. Conclusions: Left common iliac vein compression may be anatomically conditioned at least in some of the young population individuals. Lumbar hyperlordosis influence on the left common iliac vein diameter suggests that also in healthily individuals, an incorrect spinal position can promote the occurrence of the left iliac vein compression. Further studies are needed to assess the haemodynamic influence of these findings on the lower leg venous outflow.

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). 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%). 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. 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.

Iliac vein compression in an asymptomatic patient population

Deep venous thrombosis (DVT) has been noted to occur as much as 60% more frequently in the left lower extremity than in the right extremity [1]. Virchow first suggested this disparity in 1851 when he observed that iliofemoral vein thrombosis was five times more likely to occur in the left leg than in the right leg [2]. In 1957, May and Thurner [3] pathologic changes at the points where the right common iliac artery crosses over the left common iliac artery. They found that the right iliac artery compressed the left iliac vein against the fifth lumbar vertebra in 22% of 430 cadavers. A recent large number of study using computed tomography showed that mean percentage of compression was 36.6%: 29.7% (66/222) of greater than 50% compression and 7.2% (16/222) of greater than 70% compression [4]. They concluded that increasing levels of percentage compression were not associated with left-sided DVT up to 70%; however, greater than 70% compression might be associated with left DVT. The results of this study are consistent with those of previous smaller studies on iliac vein compression [5,6]. However, Kibbe et al. [7] reported that hemodynamically significant left common iliac vein compression is a frequent anatomic variant in asymptomatic individuals. Hence, they concluded that compression of the left iliac vein might represent a normal anatomic pattern that has thus far been thought as a pathologic condition. Several studies have demonstrated that therapeutic roles of lymphadenectomy in endometrial cancer and cervical cancer [8-10]. Moreover, extended systematic lymph node dissection resulted in high regional tumor control and high metastatic lymph node rate in cervical cancer [11,12]. To perform the extended systematic lymphadenectomy, it is important to know the exact anatomy of major retroperitoneal vascular structure. Kose et al. [13] demonstrated that prevalence of major retroperitoneal vascular structure anomalies was 17% and common iliac artery and/or vein anomalies was 1.8%. Presence of these anomalies may lead to devastating complications resulting in organ loss or death. However, a few data on anomalies of common iliac vessels are available. Cancer patients are at increased risk of venous thromboembolism and pulmonary embolism. For prediction of venous thromboembolism, several biomarkers were introduced including blood count analysis (elevated leukocyte and platelet count and decreased hemoglobin), D-dimer, prothrombin fragment, soluble P-selectin, and clotting factor VII [14]. Furthermore, risk assessment models were developed that include clinical and laboratory markers. From a clinical perspective, it would be helpful to have biomarkers that enable early identification of cancer patients at risk of venous thromboembolism and to target anticoagulation for primary prevention of venous thormboembolism based on risk stratification. In summary, severe compression of the common iliac vein may be associated with left-sided DVT. We should be concerned about the degree of compression to the common iliac vein during systematic para-aortic and pelvic lymphadenectomy for the treatment of gynecologic cancer patients. To prevent life threatening bleeding during systematic lymphadenectomy, it is important to know the exact anatomy of major retroperitoneal vascular structure including common iliac vessels [15]. Thromboprophylaxis is considered to reduce venous thromoembolism using several biomarkers and clinical parameters.

Purpose: To develop a strategy for the iliac vein stenting in patients with a combination of the left common iliac vein (LCIV) compression stenosis and pelvic venous insufficiency (PVI). Methods: This prospective comparative cohort study included 55 patients with hemodynamically significant LCIV stenosis out of 285 females with PVI screened in 2014–2022. All 55 patients underwent duplex ultrasound, multi-detector computed venography, ovarian venography, and multiplanar pelvic venography. Patients underwent LCIV stenting or the left gonadal vein (LGV) embolization as the primary intervention. The endpoints (chronic pelvic pain [CPP] relief, patency of stents, and reduction in pelvic venous reflux [PVR]) were evaluated 1 and 10 days, as well as 1, 6, and 12 months after the procedure. All patients received antithrombotic therapy after the interventions. Results: The primary LCIV stenting was performed in 49 patients and resulted in the CPP relief in 69.4%, pain reduction from 7.9±1.3 to 1.7±1.1 visual analog scale (VAS) scores (p=0.005), and substantial reduction of PVR in LGV (from 4.3±0.6 seconds to 1.9±0.3 seconds, p=0.003). The LGV embolization as the second stage of treatment was performed in 30.6% of patients with the LGV reflux greater than 5 seconds as a possible cause for the CPP persistence. The primary LGV embolization failed in 100% of patients (no changes in CPP and PVR). The LCIV stenting at the second stage resulted in the CPP relief within 10 days and the pelvic venous reflux (PVR) reduction. There were no complications of stenting, and the patency of stents in the follow-up period was 100%. Postembolization syndrome occurred in 9.5% of patients. No thromboses of the veins of the pelvis and lower extremities were identified. Conclusion: Treatment of patients with a combination of LCIV compression and PVI involves staged endovascular interventions: the LCIV stenting should be considered the first-line treatment, while the LGV embolization is performed when the PVI symptoms persist for more than 6 months and is not acceptable as the first-line treatment. Clinical Impact The developed strategy of endovascular treatment for the combination of left common iliac vein (LCIV) and pelvic venous insufficiency (PVI) provides an effective elimination of chronic pelvic pain (CPP) and reflux in the pelvic veins and avoids unnecessary embolizations of the gonadal veins, thereby eliminating possible risks related to complications of embolization. The use of antithrombotic therapy is an effective and safe approach for preventing venous thromboembolic events after endovascular interventions.

Decreased incidence of left common iliac vein compression in patients with abdominal aortic aneurysms

The goal of this study was to assess the degree of the left common iliac vein (LCIV) compression by the right common iliac artery (RCIA) on magnetic resonance imaging (MRI), and verify differences in compression measurements in end-inspiration, end-expiration, supine, and prone decubitus between patients with and without symptoms in the lower limbs.Methods and Results:A total of 82 consecutive participants provided informed consent and underwent pelvic MRI for different clinical indications other than vascular-related disorders. The participants answered a questionnaire about venous disease in the lower limbs and history of previous deep vein thrombosis. This study measured the area and diameter of the LCIV at the site of the crossing with the RCIA and in the uncompressed caudal LCIV segment. Statistical analysis was performed to compare the degree of LCIV compression by the RCIA and verify differences in compression measurements. A total of 71 participants were included; 46.6% were in group A and did not experience signs and symptoms in lower limbs and 53.6% were in group B and answered at least one question with a positive answer. It was observed that there was a statistically significant difference between groups for end-expiration. No statistically significant differences were observed for all other measurements. A substantial percentage of the asymptomatic and symptomatic population showed compression of the LCIV, suggesting there are no clear relationships between stenosis and non-specific symptomatology in the general population.

No. 50 May-Thurner syndrome: can it be diagnosed on a solitary MRV study?

To determine if compression of the left common iliac vein (LCIV) by the right common iliac artery is associated with left-sided deep venous thrombosis (DVT). This institutional review board-approved case-control study was performed in a cohort of 230 consecutive patients (94 men, 136 women; mean age, 57.5 years; range, 10-94 years) at one institution who had undergone contrast material-enhanced computed tomography of the pelvis prior to a diagnosis of unilateral DVT. Demographic data and information on risk factors were collected. Two board-certified radiologists determined iliac vein compression by using quantitative measures of percentage compression {[1 minus (LCIV diameter at point of maximal compression/distal right common iliac vein diameter)] times 100%}, as well as qualitative measures (none, mild, moderate, severe), with estimates of measurement variability. Logistic regression analysis was performed (independent variable, left vs right DVT; dependent variable, iliac vein compression). Cutpoints of relevant compression were evaluated by using splines. Means (with 95% confidence intervals [CIs]) and odds ratios (ORs) (and 95% CIs) of left DVT per 1% increase in percentage compression were calculated. Patients with right DVT were more likely than those with left DVT to have a history of pulmonary embolism. Overall, in all study patients, mean percentage compression was 36.6%, 66 (29.7%) of 222 had greater than 50% compression, and 16 (7.2%) had greater than 70% compression. At most levels of compression, increasing compression was not associated with left DVT (adjusted ORs, 1.00, 0.99, 1.02) but above 70%, LCIV compression may be associated with left DVT (adjusted ORs, 3.03, 0.91, 10.15). Increasing levels of percentage compression were not associated with left-sided DVT up to 70%; however, greater than 70% compression may be associated with left DVT. http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111580/-/DC1.

Objective By using computer tomography (CT) to evaluate the left common iliac vein (LCIV) minor diameter and stenosis in deep vein thrombosis (DVT) patients and normal population,and to explore the correlation between LCIV compression and left-sided DVT.Methods Measurement and calculation of LCIV minor diameter and stenosis were conducted in 19 right-sided DVT,60 left-sided DVT and 218 control subjects.Multiple factors regression analysis was used to study the correlation of LCIV minor diameter and stenosis with left-sided DVT.Results In control group,51.8％ had greater than 50％ compression of LCIV,and 24.3％ had greater than 70％ compression.LCIV diameter in women [(4.7 ± 2.7) mm] was significantly smaller than that of men [(6.6 ± 3.3) mm,P ＜ 0.05)].LCIV diameter in leftsided DVT [(2.4 ± 1.0) mm] was significantly smaller than that in control group [(5.4 ± 3.1) mm,P ＜0.001)] or right-sided DVT [(6.2 ± 1.8) mm,P ＜0.01].LCIV stenosis in left-sided DVT [(78 ±8) ％]was higher than that in control group [(49 ±25)％,P ＜0.01)] or right-sided DVT [(38 ±21)％,P ＜0.01)].The odds of left DVT increased by a factor of 2.69 for each millimeter decrease in LCIV diameter (P ＜ 0.001,95％ CI 1.91-3.77),and 2.78 for each ten percent increase in LCIV stenosis (P ＜ 0.001,95％ CI 1.95-3.96).With LCIV stenosis ＞75％,the risk of left DVT was associated with an 11.10-fold increase,and with LCIV diameter ＜ 2.5 mm,the risk was associated with a 13.57-fold increase.Conclusions LCIV compression was an independent risk factor for left-sided DVT.Patients with severe LCIV compression were at high risk for left-sided DVT. Key words: Venous thrombosis; Risk factors; Iliac vein

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

BackgroundMay–Thurner syndrome is an anatomical condition characterized by compression of the left common iliac vein by the right common iliac artery, causing venous outflow obstruction. It is an uncommon cause of deep vein thrombosis and is more prevalent among women. This paper highlights the importance of considering May–Thurner syndrome in young males without risk factors presenting with left lower limb pain, as endovascular treatment may be required.Case presentationA 23 year-old Caucasian male presented with a 1-week history of left lower limb pain, edema, and pallor. He was found to have an unprovoked deep vein thrombosis on Doppler ultrasound involving the left fibular, soleus, gastrocnemius, popliteal, femoral, common femoral, and external iliac veins. A heparin infusion was commenced as the initial treatment for deep vein thrombosis. Further investigation with computer tomography pulmonary angiogram and computer tomography venography of the abdomen and pelvis showed bilateral pulmonary emboli and left common iliac vein compression with left common, internal, and external iliac vein thrombosis. He was diagnosed with May–Thurner syndrome despite having no risk factors. A retrievable Cook Celect Platinum inferior vena cava filter was placed, and thrombus of the left common femoral, external, and common iliac veins was treated successfully with AngioJet thrombectomy, thrombolysis using 200,000 units of urokinase, angioplasty and stenting using two Cook Zilver Vena venous self-expanding stents. Therapeutic enoxaparin was commenced on discharge. His filter was removed after 10 weeks. Hematological follow-up 4 months later showed an overall negative thrombophilia screen, and anticoagulation was switched to apixaban. He has had no recurrent thrombosis.ConclusionsClinicians should have a low threshold to investigate for May-Thurner syndrome in patients with left lower limb venous thrombotic events regardless of risk factors, as endovascular treatment may be required to minimize the long-term sequelae of deep vein thrombosis. Duplex ultrasound can be used initially for diagnosis, and computer tomography venography used subsequently if the common iliac vein is not visualized on ultrasound. Endovascular treatment is preferred over anticoagulation alone, especially in otherwise fit patients presenting early, the aim being to reduce the chances of chronic venous hypertension in the lower limb.

Objectives: This study aimed to assess what diameter constitutes clinically-significant left common iliac vein (LCIV) compression in patients with May-Thurner syndrome (MTS). Materials and Methods: Nineteen patients with MTS were over a 10-year period. Minimum LCIV diameter was compared to 100 asymptomatic controls and 27 age- and gender-matched controls. Results: Mean LCIV diameter in MTS group was 3.82 mm (standard deviation [SD] 1.38), control group (mean 7.17 mm SD 3.19,P&lt; 0.0001), and matched control group (mean 6.86 mm SD 3.03,P= 0.007). Statistical threshold analysis showed in MTS patients, a LCIV diameter of 4.7mm or less had an 87.5% sensitivity and 72.7% specificity for the diagnosis. Conclusions: Patients with MTS had a minimum LCIV diameter threshold of 4.7mm, and this can be used in correlating the diagnosis of MTS on computed tomography. However, minimum diameters less than 4.7 mm are also seen in the general population and as such compression alone does not constitute a diagnosis of MTS.

Contemporary outcomes after venography-guided treatment of patients with May-Thurner syndrome.

May-Thurner syndrome (MTS), also known as the iliac vein compression syndrome, is an anatomic anomaly in which the compression of the left common iliac vein by an overlying right common iliac artery leads to blood stasis, which predisposes to deep venous thrombosis (DVT) in the iliofemoral venous system. We present a case of a female with a history of DVT and currently on warfarin with a therapeutic international normalized ratio (INR), admitted with left leg swelling, redness, and intractable pain. Venous Doppler scan confirmed a massive DVT from the level of the left common femoral vein to the popliteal vein. The clot recurred after an unsuccessful trial of argatroban, in-line pharmacokinetic thrombolysis with local catheter-based alteplase infusion, and interventional radiology (IR)-guided mechanical thrombectomy. Subsequently, the patient was diagnosed as MTS with overlying left common iliac vein compression, as evident on venous Doppler ultrasound. She was managed successfully by venous stent placement and ongoing systemic anticoagulation with fondaparinux.