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.

Three-Year Outcomes of the Abre Venous Self-Expanding Stent System in Patients with Symptomatic Iliofemoral Venous Outflow Obstruction.

PURPOSE: To report 36-month outcomes and subgroup analysis of the ABRE study evaluating the safety and effectiveness of the Abre venous self-expanding stent system for the treatment of symptomatic iliofemoral venous outflow obstruction disease. METHODS: The ABRE study was a prospective, multicenter, nonrandomized study that enrolled and implanted Abre venous stents in 200 participants (mean age 51.5 years [SD ± 15.9], 66.5% women) with symptomatic iliofemoral venous outflow obstruction at 24 global sites. Outcomes assessed through 36 months included patency, major adverse events, stent migration, stent fracture, and quality-of-life changes. Adverse events and imaging studies were adjudicated by independent clinical events committee and core laboratories, respectively. RESULTS: Primary, primary-assisted, and secondary patency through 36 months by Kaplan-Meier estimates were 81.6%, 84.8%, and 86.3%, respectively. The cumulative incidence of major adverse events through 36 months was 10.2%, mainly driven by 12 thrombosis events. Subgroup analyses demonstrated a primary patency of 76.5% in the acute deep vein thrombosis group, 70.4% in the postthrombotic syndrome group, and 97.1% in the nonthrombotic iliac vein lesion group through 36 months. The overall mean lesion length was 112.4 mm (SD ± 66.1). There were no stent fractures or migrations in this study. Quality of life and venous functional assessments demonstrated significant improvements from baseline to 36 months across all patient subsets. CONCLUSIONS: Results from the ABRE study demonstrated sustained patency with a good safety profile after implantation of a dedicated venous stent in patients with symptomatic iliofemoral venous outflow obstruction disease.

[Cockett's syndrome, a rare differential diagnosis of unilateral inferior member oedema]. / L'image du mois. Un diagnostic différentiel rare de l'œdème de membre inférieur unilatéral : le syndrome de Cockett.

We present here a typical picture of May-Thurner syndrome, rare but treatable etiology with specific treatment, of unilateral leg oedema and thromboembolic disease of the young woman.

Nous présentons ici une image typique de syndrome de Cockett, étiologie rare mais curable par un traitement spécifique, d'œdème de membre inférieur et de maladie thrombo-embolique chez la femme jeune.

Clinical Outcomes at 3 Years After Stenting for Thrombotic and Non-thrombotic Iliac Vein Compression Syndrome Patients.

Iliac vein stenting for the treatment of iliac vein compression syndrome (IVCS) has been gradually developed. This article investigated the long-term patency and improvement of clinical symptoms after endovascular stenting for iliac vein obstruction patients. From 2020 to 2022, 83 patients at a single institution with IVCS underwent venous stent implantation and were divided into two groups: non-thrombotic IVCS (n = 55) and thrombotic IVCS (n = 28). The main stent-related outcomes include technical success, long-term patency, and thrombotic events. The technical success rate of all stent implantation was 100%. The mean length of hospital stay and cost were higher in the thrombotic IVCS group than in the non-thrombotic ICVS group, as well as the length of diseased vessel segment and the number of stents implanted were higher than in the control non-thrombotic group. The 1-, 2-, and 3-year patency rates were 85.4%, 80% and 66.7% in the thrombosis group, which were lower than 93.6%, 88.7%, and 87.5% in the control group (P = .0135, hazard ratio = 2.644). In addition, patients in both groups had a foreign body sensation after stent implantation, which resolved spontaneously within 1 year after surgery. Overall, there were statistically significant differences in long-term patency rate outcome between patients with thrombotic and non-thrombotic IVCS, the 1-, 2-, and 3-year patency rates in non-thrombotic IVCS patients were higher than those in thrombotic IVCS patients.

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.

Technical Feasibility and Clinical Efficacy of Iliac Vein Stent Placement in Adolescents and Young Adults with May-Thurner Syndrome.

PURPOSE: To report technical feasibility and clinical efficacy of iliac vein stent placement in adolescent patients with May-Thurner Syndrome (MTS). MATERIALS AND METHODS: Single-institution retrospective review of the medical record between 2014 and 2021 found 63 symptomatic patients (F = 40/63; mean age 16.1 years, 12-20 years) who underwent left common iliac vein (LCIV) stent placement for treatment of LCIV compression from an overriding right common iliac artery, or equivalent (n = 1, left IVC). 32/63 (50.7%) patients presented with non-thrombotic iliac vein lesions (NIVL). 31/63 (49.2%) patients presented with deep vein thrombosis of the lower extremity and required catheter-directed thrombolysis after stent placement (tMTS). Outcomes include technically successful stent placement with resolution of anatomic compression and symptom improvement. Stent patency was monitored with Kaplan-Meier analysis at 3, 6, 12, 24, and 36 months. Anticoagulation and antiplatelet (AC/AP) regimens were reported. RESULTS: Technical success rate was 98.4%. 74 bare-metal self-expanding stents were placed in 63 patients. Primary patency at 12, and 24-months was 93.5%, and 88.9% for the NIVL group and 84.4% and 84.4% for the tMTS group for the same period. Overall patency for the same time intervals was 100%, and 95.4% for the NIVL group and 96.9%, and 96.9% for the tMTS group. Procedural complication rate was 3.2% (2/63) with no thrombolysis-related bleeding complications. Clinical success was achieved in 30/32 (93.8%) and 29/31 (93.5%) patients with tMTS and NIVL groups, respectively. CONCLUSION: CIV stent placement in the setting of tMTS and NIVL is technically feasible and clinically efficacious in young patients with excellent patency rates and a favorable safety profile.

In situ management of late thrombosis of a renal graft vein in a patient with Cockett syndrome / Prise en charge in situ d'une thrombose tardive de la veine d'un greffon rénal chez une patiente avec un syndrome de Cockett

Late thrombosis of the renal graft vein is a rare complication that results in graft loss in the majority of cases. We describe the case of a 57-year-old female patient who had a kidney transplant 32 years ago and developed a late thrombosis of the graft vein, accompanied by extensive thrombosis in the common femoral and iliac veins. Risk factors included severe malnutrition, chronic inflammation due to an anal fistula, and Cockett syndrome. The treatment consisted of mechanical thrombectomy of the iliac vein, placement of a stent in the common iliac vein, partial thromboaspiration of the renal vein thrombus with local thrombolysis, followed by systemic anticoagulation. With this approach, renal function fully recovered without major complications.

La thrombose tardive de la veine du greffon rénal est une complication rare qui conduit à la perte du greffon dans la majorité des cas. Nous présentons le cas d'une femme de 57 ans, transplantée depuis 32 ans, qui a développé une thrombose de la veine du greffon, se manifestant par une insuffisance rénale aiguë anurique. Cette thrombose compliquait une thrombose extensive débutant dans la veine fémorale superficielle et s'étendant dans les veines fémorale commune et iliaque. La patiente présentait plusieurs facteurs de risque de thrombose veineuse, tels qu'un état de malnutrition sévère, une inflammation chronique due à une fistule anale chronique et un syndrome de Cockett. La patiente a été traitée en plusieurs étapes successives : une thrombectomie mécanique de toute la veine iliaque a d'abord été réalisée, suivie de la mise en place d'un stent dans la veine iliaque commune gauche en raison du syndrome de Cockett, puis d'une thrombo-aspiration partielle du thrombus de la veine rénale combinée à une thrombolyse locale (par urokinase) de la veine rénale via un cathéter, et enfin d'une anticoagulation systémique. Cette approche a permis une récupération complète de la fonction rénale sans complication notable. Nous rapportons cette prise en charge in situ d'une thrombose tardive de la veine d'un greffon rénal chez une patiente avec un syndrome de Cockett, ayant permis une issue favorable.

Venous compression syndromes in females: A descriptive review.

Venous compression syndromes have been described, yet the role of sex is poorly understood. Although iliac vein compression has been discussed more often with the advent of newer technologies, research has fallen short on defining epidemiology, best practices for evaluation and treatment, and differences in responses to treatment between men and females. The authors report on iliac vein compression, nonthrombotic renal vein compression, and other venous compression syndromes in females. Literature searches of PubMed were performed using the following keywords: females/females and May Thurner, venous stenting, venous outcomes, deep venous disease, deep venous compression, venous stenting, renal vein compression, renal vein surgery/stent, popliteal vein entrapment, venous thoracic vein entrapment, and popliteal vein entrapment. The articles prompted the authors to research further as the referenced articles were reviewed. Sex representation has not been addressed adequately in the research of venous compression syndromes, making the discussion of best treatment options and long-term outcomes difficult. More specific understanding of epidemiology and response to interventions will only come from research that addresses these issues directly, understanding that some of these syndromes occur rarely.

Efficacy of modified time of flight magnetic resonance venography in diagnosis of iliac vein compression syndrome.

OBJECTIVE: We investigated the diagnostic efficacy of modified time of flight magnetic resonance venography (mTOF-MRV) for iliac vein compression syndrome diagnosis by optimizing the scanning parameters and improving image quality. METHODS: A retrospective study was conducted on 69 patients who underwent routine time of flight magnetic resonance venography (TOF-MRV) and 85 patients who received mTOF-MRV. Assessment of image quality of the two methods was performed by two radiologists using a four-point method. The sensitivity, specificity, positive and negative predictive values of TOF-MRV and mTOF-MRV in the diagnosis of significant iliac vein compression (stenosis >50%) were analyzed by calculating the iliac vein stenosis rates of the two methods and using digital subtraction angiography (DSA) as the gold standard. RESULTS: Inter-observer assessment of objective data measurement revealed excellent agreement {ICC [95% confidence interval (CI)]: 0.972 (0.953 to 0.983) for TOF-MRV and 0.979 (0.965 to 0.988) for m-TOF MRV, 0.976 (0.960 to 0.986) for DSA}. The mean error of stenosis rate of mTOF-MRV was markedly smaller than that of TOF-MRV (p < 0.05). Sensitivity, specificity, positive and negative predictive values of TOF-MRV in the diagnosis of significant stenosis were 100%, 95%, 67% and 100%, respectively. The sensitivity, specificity, positive and negative predictive values of mTOF-MRV were 100%. The mean image score for the mTOF-MRV was 3.63 ± 0.59, which was significantly higher compared with that of TOF-MRV (2.19 ± 0.42). CONCLUSION: mTOF-MRV has better image quality and can accurately diagnose venous stenosis. Therefore, it can be used for the detection of iliac vein compression syndrome and further assessment after endovascular interventions.

An ultrasound imaging and computational fluid dynamics protocol to assess hemodynamics in iliac vein compression syndrome.

OBJECTIVE: Elevated shear rates are known to play a role in arterial thrombosis; however, shear rates have not been thoroughly investigated in patients with iliac vein compression syndrome (IVCS) owing to imaging limitations and assumptions on the low shear nature of venous flows. This study was undertaken to develop a standardized protocol that quantifies IVCS shear rates and can aid in the diagnosis and treatment of patients with moderate yet symptomatic compression. METHODS: Study patients with and without IVCS had their iliac vein hemodynamics measured via duplex ultrasound (US) at two of the following three vessel locations: infrarenal inferior vena cava (IVC), right common iliac vein, and left common iliac vein, in addition to acquiring data at the right and left external iliac veins. US velocity spectra were multiplied by a weighted cross-sectional area calculated from US and computed tomography (CT) data to create flow waveforms. Flow waveforms were then scaled to enforce conservation of flow across the IVC and common iliac veins. A three-dimensional (3D), patient-specific model of the iliac vein anatomy was constructed from CT and US examination. Flow waveforms and the 3D model were used as a basis to run a computational fluid dynamics (CFD) simulation. Owing to collateral vessel flow and discrepancies between CT and US area measurements, flows in internal iliac veins and cross-sectional areas of the common iliac veins were calibrated iteratively against target common iliac flow. Simulation results on mean velocity were validated against US data at measurement locations. Simulation results were postprocessed to derive spatial and temporal values of quantities such as velocity and shear rate. RESULTS: Using our modeling protocol, we were able to build CFD models of the iliac veins that matched common iliac flow splits within 2% and measured US velocities within 10%. Proof-of-concept analyses (1 subject, 1 control) have revealed that patients with IVCS may experience elevated shear rates in the compressed left common iliac vein, more typical of the arterial rather than the venous circulation. These results encourage us to extend this protocol to a larger group of patients with IVCS and controls. CONCLUSIONS: We developed a protocol that obtains hemodynamic measurements of the IVC and iliac veins from US, creates patient-specific 3D reconstructions of the venous anatomy using CT and US examinations, and computes shear rates using calibrated CFD methods. Proof-of-concept results have indicated that patients with IVCS may experience elevated shear rates in the compressed left common iliac vein. Larger cohorts are needed to assess the relationship between venous compression and shear rates in patients with IVCS as compared with controls with noncompressed iliac veins. Further studies using this protocol may also give promising insights into whether or not to treat patients with moderate, yet symptomatic compression.

Tromboembolismo pulmonar asociado a COVID-19 en paciente con síndrome de May-Thurner / COVID-19-associated Pulmonary Thromboembolism in a Patient with May-Thurner Syndrome

Introducción: El síndrome de May-Thurner es una enfermedad cuya prevalencia real es desconocida. Suele ser asintomática y las manifestaciones clínicas aparecen en el contexto de las complicaciones asociadas a la enfermedad. La aproximación diagnóstica se realiza por medio de imágenes, donde se identifican alteraciones patognomónicas que permiten descartar diagnósticos diferenciales. Se ha demostrado que la COVID-19 genera un estado protrombótico, que en contexto del síndrome de May-Thurner puede derivar en complicaciones tromboembólicas. Objetivo: Comparar la clínica y la posible relación de la enfermedad tromboembólica venosa en el curso de la COVID-19 en pacientes con SMT. Caso clínico: Mujer de 24 años, secretaria de profesión y residente en Bucaramanga. Presentó un cuadro clínico de 20 días de evolución que inició con rinorrea hialina, tos ocasional y mialgias; cinco días después manifestó fiebre no cuantificada y tos con expectoración hemoptoica. Conclusiones: Dentro de la fisiopatología de la infección por SARS-CoV-2 se desarrollan mecanismos procoagulantes, lo cual incrementa el riesgo de eventos trombóticos en pacientes con o sin factores de riesgo(AU)

Introduction: May-Thurner syndrome is a disease whose actual prevalence is unknown. It is usually asymptomatic and clinical manifestations appear in the context of complications associated with the disease. The diagnostic approach is performed by imaging, where pathognomonic alterations are identified to rule out differential diagnoses. It has been demonstrated that COVID-19 generates a prothrombotic state, which particularly in patients with May-Thurner syndrome would lead to thromboembolic complications. Objective: To compare the clinical and possible relationship of venous thromboembolic disease in the course of COVID-19 in patients with May-Thurner syndrome. Clinical case: 24-year-old woman, secretary by profession and resident in Bucaramanga, Colombia. She presented a clinical picture of 20 days of evolution that began with hyaline rhinorrhea, occasional cough and myalgias; five days later she manifested unquantified fever and cough with hemoptotic expectoration. Conclusions: Within the pathophysiology of SARS-CoV-2 infection, procoagulant mechanisms develop, which increases the risk of thrombotic events in patients with or without risk factors(AU)

The utility of computed tomography venography in the routine evaluation of patients who present to a lymphedema center with lower extremity edema.

OBJECTIVE: Computed tomography venography (CTV) is not routinely used to screen patients presenting with a presumed lower extremity lymphedema diagnosis for left iliac vein obstruction (IVO) or May-Thurner syndrome (MTS). The objective of this study is to determine the utility of routine CTV screening for these patients by evaluating the proportion presenting with clinically significant CTV-identified left IVO. METHODS: We retrospectively reviewed 121 patients who had presented to our lymphedema center with lower extremity edema between November 2020 and May 2022. Information regarding demographics, comorbidities, lymphedema characteristics, and imaging reports was collected. Cases of IVO present on CTV were reviewed by a multidisciplinary team to determine the clinical significance of the CTV findings. RESULTS: Of the patients with complete imaging studies, 49% (n = 25) had abnormal lymphoscintigraphy findings, 45% (n = 46) had reflux on ultrasound, and 11.4% (n = 9) had IVO on CTV. Seven patients (6%) had CTV findings of IVO and edema of either the isolated left (n = 4) or bilateral (n = 3) lower extremities. Cases of IVO on CTV were determined by the multidisciplinary team to be the predominant cause of lower extremity edema for three of these seven cases (43%; or 2.5% of all 121 patients). CONCLUSIONS: Six percent of patients presenting to a lymphedema center with lower extremity edema had left-sided IVO on CTV suggestive of MTS. However, the cases of IVO were determined to be clinically significant <50% of the time or for 2.5% of all patients. CTV should be reserved for patients with isolated left-sided or bilateral lower extremity edema with a greater left-sided component and a history of findings that raise clinical suspicion for MTS.

Spontaneous iliac vein rupture and thrombosis in patients with May-Thurner syndrome: A narrative review.

Spontaneous iliac vein rupture (SIVR) is extremely rare and can lead to serious complications, including death. Etiologies include inflammatory processes and hormonal and mechanical triggers, with concomitant May-Thurner syndrome (MTS) being a rare cause. Management can be challenging due to the difficult balance between reducing thrombotic burden and life-threatening hemorrhage that can result from aggressive anticoagulation. Furthermore, surgical interventions are associated with high mortality, making conservative management more desirable. We report a case of SIVR with retroperitoneal hematoma and concurrent MTS that was successfully managed using conservative measures. We further provide a narrative review of the current literature addressing the diagnosis, management, and outcome of SIVR focusing on cases with concurrent MTS.

Effect of stent treatment on hemodynamics in iliac vein compression syndrome with collateral vein.

BACKGROUND: Iliac vein compression syndrome (IVCS) leads to blood flow obstruction in the lower extremities and is usually treated with stents, but stenting may worsen the hemodynamics and increase the risk of thrombosis in the iliac vein. The present work evaluates the advantages and disadvantages of the stent on IVCS with a collateral vein. METHODS: The computational fluid dynamics method is adopted to analyze the preoperative and postoperative flow fields in a typical IVCS. The geometric models of the iliac vein are constructed from medical imaging data. The porous model is used to simulate the flow obstruction in IVCS. RESULTS: The preoperative and postoperative hemodynamic characteristics in the iliac vein are obtained, e.g., the pressure gradient at two ends of the compressive region and the wall shear stress. It is found that the stenting restores the blood flow in the left iliac vein. CONCLUSION: Impacts of the stent are classified into short-term and long-term effects. The short-term effects are beneficial in relieving IVCS, i.e., shortening the blood stasis and reducing the pressure gradient. The long-term effects increase the risk of thrombosis in the stent, i.e., enlarging wall shear stress due to a large corner and a diameter constriction in the distal vessel, and suggests the need to develop a venous stent for IVCS.