Is the May-Thurner Syndrome a Major Risk Factor for Deep Vein Thrombosis in Total Hip Arthroplasty?

Background: May-Thurner syndrome (MTS) is iliac vein compression syndrome associated with postoperative deep vein thrombosis (DVT) resulting from chronic compression of the left iliac vein against lumbar vertebrae by the overlying right or left common iliac artery. MTS is not well known as a risk factor for DVT after total hip arthroplasty (THA). We evaluated the incidence of DVT after THA and analyzed if the MTS is a risk factor for DVT after THA. We hypothesized that MTS would be associated with an increased risk of developing DVT after THA. Methods: All patients > 65 years of age who underwent THA between January 1, 2009, and January 12, 2017, were identified. Among them, the patients who presented for postoperative DVT of the lower extremity were reviewed with medical record data. MTS was diagnosed with computed tomography (CT) angiography of the lower extremity. We analyzed the demographic data, symptoms, diagnoses, and treatment of MTS patients. Results: A total of 492 consecutive patients aged > 65 years who underwent operation for THA were enrolled. Among them, 5 patients (1.0%) presented for postoperative DVT of the lower extremity. After reviewing the CT angiography of the lower extremity, 4 out of 5 DVT patients (80%) were identified as having MTS. All MTS patients were female and presented with pain and swelling of the left leg. All MTS patients were treated with systemic anticoagulation, aspiration thrombectomy, and percutaneous transluminal angioplasty. Complete resolution of thrombus was observed in all patients. Conclusions: If the diagnosis of MTS is delayed, the morbidity and mortality rates are significantly increased. Orthopedic surgeons should be aware of MTS as a risk factor for DVT after THA. Moreover, preoperative evaluation with duplex sonography or CT angiography to confirm MTS should be considered. In this regard, this study is considered to have sufficient clinical value for early diagnosis and appropriate treatment of MTS after THA.

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.

Atypical iliac vein compression in patients with symptomatic May-Thurner syndrome.

PURPOSE: We aimed to investigate the incidence, etiology, treatment, and clinical course of atypical iliac vein compressions (AIVCs) among patients with May-Thurner syndrome (MTS). METHODS: A total of 173 patients who presented with MTS were retrospectively analyzed at a single center. Computed tomographic venography (CTV) was used to diagnose MTS. An AIVC was defined as the compression of the left common iliac vein (LCIV) by structures other than the right common iliac artery (RCIA) or the compression of other venous structures in the pelvic cavity instead of the LCIV. The patients with AIVC were categorized into the LCIV compression group (category A) and non-LCIV compression group (category B). RESULTS: Ten patients with AIVC were identified (5.8%; male/female, 5/5), five in category A and five in category B. The median age of patients was 76 years (range, 51-94 years), and the median follow-up duration was 388 days (range, 12-4694 days). In category A, the LCIVs were compressed by the left common iliac artery (LCIA) (n=2), uterine leiomyoma (n=1), LCIA aneurysm (n=1), and RCIA aneurysm (n=1). In category B, the right common iliac veins were compressed by the RCIA (n=4) and L5 osteophyte (n=1). Endovascular treatment, including balloon angioplasty and stent placement, was performed in six patients, three from each group. Three patients underwent conservative treatment due to their advanced age and comorbidities. Endovascular aneurysm repair was performed in one patient with RCIA aneurysm. Follow-up images were available for six patients, and all of them had patent venous flow. CONCLUSION: The AIVC had an incidence of 5.8% (10/173) among symptomatic MTS patients and wide spectrum of etiologies. Pathogenesis-tailored endovascular treatments are safe and effective.

Common iliac vein obstruction in a symptomatic population is associated with previous deep venous thrombosis, and with chronic pelvic pain in females.

OBJECTIVE: The objectives of this study were to determine the incidence of common iliac vein obstruction, gonadal vein incompetence, and renal vein compression/stenosis and to ascertain which referral reasons were associated with common iliac vein obstruction and gonadal vein incompetence in a population symptomatic for chronic venous insufficiency. METHODS: Data were obtained from patients, at least 18 years old, who were referred to a private vascular laboratory for venous duplex ultrasound examination between 2016 and 2017. Transabdominal ultrasound was used to assess the iliac, gonadal, and renal veins in a dedicated protocol. Demographic data, referral reasons (varicose veins, lower limb pain, lower limb edema, lower limb ulcers, chronic pelvic pain [CPP]) and history of previous deep venous thrombosis (DVT) were recorded. RESULTS: Among 421 patients (78.6% female; 57.7 ± 16.7 years), 46.7% had iliac vein obstruction, 40.1% had gonadal vein incompetence, and 29.9% had renal vein compression/stenosis. Venous disorders were significantly more prevalent among female patients and on the left side. The most common referral reasons were varicose veins for both sexes, followed by lower limb pain for females and lower limb edema for males, none of which were associated with any venous obstruction or incompetence. Previous DVT was significantly associated with common iliac vein obstruction for all patients (ß = .189; P = .001), despite its being a previous known diagnosis for only 11.4% of patients. Among females, CPP was also significantly associated with common iliac vein obstruction and gonadal vein incompetence (ß = .246 [P < .001] and ß = .201 [P = .012], respectively). Among those with CPP in this study, common iliac vein obstruction, with and without gonadal vein incompetence (33% and 35%, respectively), was more prevalent than gonadal vein incompetence alone (14%). CONCLUSIONS: History of DVT, as well as CPP among females warrants investigations of common iliac vein obstruction. Common iliac vein obstruction is likely to be a more significant contributor to CPP than gonadal vein incompetence.

Evaluation of incidence and clinical significance of obturator hook sign as a marker of chronic iliofemoral venous outflow obstruction in computed tomography venography.

OBJECTIVE: The aim of this paper was to describe the obturator hook sign (OHS), a distinctive dilated angled vein similar to a hook, by computed tomography venography (CTV). It is identified mainly on direct CTV (DCTV) as opposed to indirect CTV (ICTV), evidencing obturator vein engorgement as a marker of hemodynamically significant collateralization and representing an indirect sign for chronic iliac vein outflow obstruction. METHODS: All CTV studies of lower limbs performed from January 2014 to August 2018 in Galway University Hospital and the Galway Clinic were retrospectively reviewed. Data were analyzed using SPSS software (version 25.0; IBM Corp, Armonk, NY). RESULTS: In total, 531 CTV studies were reviewed, of which 122 (23%) were performed for acute deep venous thrombosis, 183 (35%) for follow-up after iliac stenting, and 109 (21%) for etiologic study of chronic venous disease. For the purpose of analysis for the presence of OHS, only first-time CTV studies were included in patients who were never submitted to venous intervention (n = 296), of which 40 were DCTV (14%) and 256 were ICTV (86%). Two groups were defined according to whether OHS was present, and significant predictors were identified: female sex (P = .038), younger age (P < .0001), DCTV (P < .0001), nonthrombotic iliac vein lesion (P < .001), past history of iliofemoral deep venous thrombosis (P < .0001), and dilated pelvic veins (P < .0001). OHS was significantly more common in chronic occlusions compared with chronic stenosis or acute occlusion (P < .0001). Findings from DCTV and ICTV were compared with results from ascending venography as the "gold standard," and the sign proved to have high specificity and positive predictive value (100% for both tests), whereas sensitivity and negative predictive value were low for both DCTV (65% [95% confidence interval (CI), 43%-84%] and 11% [95% CI, 7%-18%], respectively) and ICTV (8% [95% CI, 4%-14%] and 6% [95% CI, 9%-20%], respectively). From analysis of the remaining CTVs, particularly follow-up after iliac stenting, an interesting fact was recognized: successful venous stenting was associated with OHS disappearance, and stent occlusion was also sometimes associated with OHS reappearance or appearance de novo. CONCLUSIONS: The identification of hemodynamically significant lesions in patients with clinically significant chronic venous disease is the aim of any form of imaging. In this study, we have depicted a previously undescribed sign that is straightforward to identify, particularly in DCTV, immediately pointing us toward hemodynamically significant chronic iliac venous outflow obstruction diagnosis. It is too early to call it pathognomonic, but perhaps comparative analysis involving data from additional centers could lead to this conclusion.

Prevalência de compressão da veia ilíaca esquerda em imagens tomográficas de uma população / Prevalence of left iliac vein compression on computed tomography scans from a population

Resumo Contexto A síndrome de May-Thurner (SMT) é a compressão da veia ilíaca esquerda (VIE) entre a artéria ilíaca direita e o corpo vertebral associada à hipertensão venosa crônica unilateral no membro inferior esquerdo. Porém, o achado tomográfico da compressão não necessariamente se reflete em sintomas. Objetivos Avaliar o achado de compressão da veia ilíaca esquerda em tomografias realizadas por outros motivos. Métodos Angiotomografias ou tomografias computadorizadas (TCs) com fase venosa foram analisadas. Foram coletados os dados demográficos e o motivo do exame, quando presente, e foi analisada a relação do diâmetro da veia ilíaca esquerda no ponto de maior compressão com um ponto a montante. Resultados De janeiro a julho de 2016, 590 tomografias foram analisadas, sendo 357 de mulheres e 233 de homens. A compressão da VIE ocorreu em 87 (14,74%) pacientes, dos quais 74 (85,05%) eram mulheres e 13 (14,9%) homens. O diâmetro médio do ponto de maior compressão entre os pacientes que apresentavam VIE < 5 mm foi de 4,4 mm, variando de 2,67 mm a 4,97 mm. O diâmetro no ponto de maior compressão representou até metade do diâmetro na última imagem justaposta ao corpo vertebral (índice de 0,5) em 179 (30,3%) dos pacientes. Conclusões Nosso estudo sugere que a ocorrência de compressão da VIE em TC de pacientes aleatórios, sem conhecimento de insuficiência venosa crônica ou TVP em MIE, é comum. Isso mostra que o achado tomográfico de compressão não necessariamente resulta em sintomas e não deve ser a única razão para tratar um paciente.

Abstract 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.

Incidence and Risk Factors of Deep Venous Thrombosis in Asymptomatic Iliac Vein Compression: A Prospective Cohort Study.

BACKGROUND: Deep vein thrombosis (DVT) may be associated with iliac vein compression. Up to now, the majority of data has come from a retrospective study about the correlation between DVT and iliac vein compression. This prospective study was to determine the incidence of DVT in individuals with iliac vein compression and identify risk factors predictive of DVT. METHODS: A total of 500 volunteers without symptoms of venous diseases of lower extremities and overt risk factors of deep venous thrombosis between October 2011 and September 2012 in Shijitan Hospital were enrolled in this cohort study. All the participants underwent contrast-enhanced abdominal computed tomography (CT) to evaluate iliac vein compression. Baseline demographic information and degree of iliac vein compression were collected. They were categorized into ≥50% or <50% iliac vein compression group. Ultrasound examination was performed to screen DVT at the time of CT examination and 3, 6, 9, and 12 months after the examination. Primary event was DVT of ipsilateral lower extremity. Correlation between DVT and iliac vein compression was estimated by multivariate Logistic regression after adjusting for age, gender, malignancy, surgery/immobilization, chemotherapy/hormonal therapy, and pregnancy. RESULTS: In 500 volunteers, 8.8% (44) had ≥50% iliac vein compression and 91.2% (456) had <50% iliac vein compression. Ipsilateral DVT occurred in six volunteers including two in iliofemoral vein, two in popliteal vein, and two in calf vein within 1 year. Univariate analysis showed that the incidence of DVT was 6.8% in ≥50% compression group, significantly higher than that in <50% compression group (0.7%) (χ2 = 12.84, P = 0.01). Patients with malignancy had significantly higher incidence of DVT than those without malignancy (χ2 = 69.60,P< 0.01). Multivariate Logistic regression indicated that iliac vein compression and malignancy were independent risk factors of DVT. After adjustment for malignancy, patients with ≥50% iliac vein compression had 10-fold increased risk of developing DVT (adjusted relative risk [RR] = 10.162, 95% confidence interval [CI]: 1.149-89.865, P = 0.037). In subgroup analysis, patients with malignancy and ≥50% iliac vein compression had 12-fold increased the risk of DVT than those without malignance and ≥50% compression (RR = 12.389, 95% CI: 2.327-65.957, P = 0.003). CONCLUSIONS: Iliac vein compression is common, but the incidence of DVT is low. Only individuals with ≥50% iliac vein compression or compression combined with other risk factors might have significantly increased the risk of DVT. Further study is recommended to improve prevention strategies for DVT in significant iliac vein compression.

Iliac vein compression syndrome: literature review / Síndrome de compressão da veia ilíaca: revisão de literatura

Iliac vein compression syndrome is a clinical condition in which the right common iliac artery extrinsically compresses the left common iliac vein. The syndrome predominantly affects young women between their 2nd and 4th decades of life. In view of the syndrome's potential complications, it should be recognized/diagnosed and treated in symptomatic patients before it causes irreversible damage to patients' venous systems. Noninvasive methods, such as venous color Doppler US are reasonable screening methods, but angiotomography and magnetic resonance angiography are more reliable diagnostic tools and the method of choice for confirmation of diagnosis remains multi-plane phlebography with measurement of pressure gradients. Endovascular treatment (angioplasty with placement of self-expanding stents) is safe and effective and can replace open surgical reconstruction and/or anticoagulation alone...

A Síndrome de Compressão da Veia Ilíaca (SCVI) é uma situação clínica na qual a artéria ilíaca comum direita comprime extrinsecamente a veia ilíaca comum esquerda. Há uma predominância em mulheres jovens, entre a segunda e a quarta décadas de vida. Levando-se em consideração as complicações potenciais da síndrome, esta deve ser reconhecida/diagnosticada e tratada, em pacientes sintomáticos, antes que cause alterações irreversíveis no sistema venoso do paciente. Métodos não invasivos, como o US-Doppler colorido, quando realizados por examinadores experientes, são métodos de triagem razoáveis; porém, a angiotomografia e a angiorressonância são mais fidedignas. O método de escolha para a confirmação diagnóstica consiste na flebografia, em múltiplas incidências, com aferição de gradientes pressóricos. O tratamento endovascular (angioplastia com colocação de stent autoexpansível) é seguro e efetivo, podendo substituir a reconstrução cirúrgica aberta e/ou a anticoagulação isolada...

Incidence and clinical significance of iliac vein compression.

OBJECTIVES: To determine the frequency of left common iliac vein (CIV) compression by the right common iliac artery (CIA) based on CT scan images. METHODS: CT scan images were reviewed and the diameter of CIV was measured at the area of minimal diameter and compared to the distal adjacent segment and the contralateral CIV at the same level. Medical records were reviewed for symptoms, deep vein thrombosis (DVT) and risk factors that might be associated with DVT. Data were analyzed with SPSS program using both Chi square and t test. A p < 0.05 was considered statistically significant. Linear regression (R2) was used to evaluate correlation. RESULTS: A total of 300 complete records were reviewed. The mean age was 51.89 years, with 126 (42%) males. Comparison between the two groups (>70% vs <70%) showed similar clinical factors such as history of DVT, surgery, immobilization, malignancy, limb trauma, pregnancy, obesity, CHF, and smoking. There were more females with CIV compression of 70% or more than males (19.5% vs 11.1% P < .049). CONCLUSION: Diameter stenosis more than 70% was present in 30.6% of cases with higher incidence in females. The presence of stenosis was not associated with the presence of clinical symptoms.

Endovascular treatment for symptomatic iliac vein compression syndrome: a prospective consecutive series of 48 patients.

BACKGROUND: We sought to assess the prevalence of iliac vein compression syndrome (IVCS) in patients with unilateral left lower limb chronic venous disease and evaluate the feasibility and effectiveness of endovascular treatment for IVCS. METHODS: We conducted a prospective cohort study of 48 consecutive patients diagnosed with IVCS between December 2008 and May 2012. We divided the patients into 2 groups: thrombotic IVCS (n = 12) and nonthrombotic IVCS (n = 36). We evaluated the perioperative, 30-day, and 1-year outcomes of endovascular treatment. We estimated the stent patency rate using the Kaplan-Meier method. RESULTS: The prevalence of IVCS within our cohort was 14.8% (48/324). The technical success rate of the endovascular treatment was 95.8%. There was no death, pulmonary embolism, or contrast-induced nephropathy among the patients. The 1-year primary patency rate was 93.0%. There was no significant difference between the thrombotic and nonthrombotic IVCS groups (P = 0.156). Perioperative complications were minor and improved quickly. The median pain level recorded on a visual analogue scale declined from 4.5 to 1.2 (P < 0.05) in the thrombotic ICVS group and from 3.3 to 0.3 (P < 0.05) in the nonthrombotic ICVS group. The edema relief rates in the thrombotic and nonthrombotic ICVS groups were 81.8% and 58.5%, respectively. The cumulative recurrence free ulcer healing rate was 71.4% 12 months after treatment. CONCLUSIONS: IVCS is more common than previously thought among patients with unilateral left lower limb chronic venous disease. Endovascular therapy, a minimally invasive approach to treating venous lesions, is a feasible and effective treatment for left-sided IVCS and has a high technical success rate and an acceptable complication profile.

May-Thurner syndrome: update and review.

May-Thurner syndrome (MTS) is an anatomically variable condition of venous outflow obstruction caused by extrinsic compression. Although this syndrome is rare, its prevalence is likely underestimated. The pathology of this condition is secondary to a partial obstruction of the common iliac vein by an overlying common iliac artery with subsequent entrapment of the left common iliac vein. Regardless of the mechanism, this causes partial or complete impedance to the iliac vein outflow with subsequent possible obstruction and extensive ipsilateral deep vein thrombosis (DVT) of the ipsilateral extremity. Clinical presentations include, but are not limited to pain, swelling, venous stasis ulcers, and skin discoloration. With extensive DVT, postphlebetic syndrome, with all of its sequelae, may also develop. Treatment is based on the clinical presentation and includes staged thrombolysis with/without prophylactic retrievable inferior vena cava filter placement, followed by angioplasty/stenting of the left iliac vein in MTS patients with extensive DVT. This review highlights the variable presentations of MTS and outlines possible management within the current Society for Vascular Surgery consensus.