May-Thurner Syndrome Research Articles

Intravascular US: Applications in Interventional Radiology.

Interventional radiology applications of intravascular US (IVUS) continue to expand, complementing intraprocedural angiography and providing a unique vantage from which to guide endovascular interventions. Vascular pathologic conditions become sonographically visualized rather than inferred from the planar appearance of the opacified vascular lumen. Perivascular targets become sonographically visualized rather than approximated on the basis of fluoroscopic landmarks. The authors introduce broad categories of IVUS catheters, namely radial and side-firing varieties, as well as prevailing options for each and their technical specifications. Common applications within interventional radiology are covered in a systems approach, including deep venous thrombosis, May-Thurner syndrome, nutcracker syndrome, transjugular intrahepatic portosystemic shunts, aortic interventions, peripheral arterial disease, and endovascular or perivascular biopsy. Discussions are accompanied by technical pearls from the authors, and summarized evidence where IVUS has been shown to reduce procedural time, intravascular contrast agent dose, radiation exposure, and morbidity in each space is presented. Finally, emerging applications and future directions are discussed. ©RSNA, 2022.

MAY-THURNER SYNDROME: UNCOMMONLY COMMON

SESSION TITLE: Thrombosis Jamboree: Rare and Unique Cases SESSION TYPE: Rapid Fire Case Reports PRESENTED ON: 10/19/2022 12:45 pm - 1:45 pm INTRODUCTION: May-Thurner syndrome is a venous compression syndrome characterized by common iliac vein compression between the left lumbar spine and the common iliac artery. The most common pattern is left common iliac vein compression by the right common iliac artery. Clinical presentation can vary from asymptomatic to signs and symptoms of venous stasis. This can include lower extremity swelling, edema, pain, and ulceration. More advanced stenosis results in deep vein thrombosis (DVT). The exact incidence and prevalence of MTS are unknown; however, it is felt to be underdiagnosed. MTS can be attributed to 2-5% of all venous thromboembolism (VTE). We present a case of DVT and pulmonary embolism (PE) in a patient who was found to have MTS. CASE PRESENTATION: The patient was an 83-year-old male with diabetes mellitus and hypertension who presented to the emergency department (ED) for evaluation of dyspnea on exertion. In the ED he was noted to be in respiratory distress, but otherwise hemodynamically stable. He was hypoxic, requiring supplemental oxygen via nasal cannula. Serum studies and chest radiographs were unremarkable. Computed tomography angiography of the chest revealed saddle pulmonary embolism extending into bilateral upper lobar arteries. After a thorough history, it was felt the VTE was unprovoked. The patient was admitted to the ICU and underwent emergent catheter-directed pulmonary artery thrombectomy. Anticoagulation was initiated with unfractionated heparin infusion. An echocardiogram revealed normal left ventricular function and a moderately dilated right ventricle. Lower extremity ultrasound revealed extensive clot burden in the left femoral, popliteal, and tibial veins. Lower extremity angiography revealed compression of the left common iliac vein. He subsequently underwent venous thrombectomy and common iliac vein stenting. He tolerated the procedures and hospitalization well and was ultimately discharged in stable condition DISCUSSION: MTS is characterized by compression of the left common iliac vein by the right common iliac artery, with resultant stenosis and venous stasis. It is estimated to cause 2-5% of all VTE although the prevalence may be higher (1). Diagnosis requires a high clinical suspicion, as MTS does not present specific findings in the setting of VTE. Initial presentation could range from lower extremity swelling to pain, venous stasis, or ulcerations – all of which could be attributed to the DVT (2). Making the diagnosis is important, however, as it presents a chance for therapeutic endovascular intervention. CONCLUSIONS: Our case highlights first that MTS may be very underdiagnosed. Secondly, it is a cause of provoked venous thromboembolism. It may therefore present a therapeutic endovascular option and may alter the duration of anticoagulation. For these reasons, the clinician should consider MTS in the differential for all VTE, and especially for recurrent VTE Reference #1: 1. Sigua-Arce P, Mando R, Spencer L, Halalau A. Treatment of May–Thurner's syndrome and associated complications: A multicenter experience. Int J Gen Med. 2021;14:4705–10. Reference #2: 2. Knuttinen MG, Naidu S, Oklu R, Kriegshauser S, Eversman W, Rotellini L, et al. May-Thurner: Diagnosis and endovascular management. Cardiovasc Diagn Ther. 2017;7(Suppl 3):S159–64. DISCLOSURES: No relevant relationships by Wajahat Khan No relevant relationships by Nelson Okoh

Left leg swelling: A case of May-Thurner syndrome

May-Thurner Syndrome is a left common iliac vein thrombosis caused due to its compression by right common iliac artery, an anatomical variant that is underreported. We report the case of a 52 year old female who presented with left leg swelling and was diagnosed with May-Thurner Syndrome. She underwent an iliac vein thrombectomy and was discharged on life-long anticoagulants.

Restoring Venous Patency with the ClotTriever Following Deep Vein Thrombosis

Although randomized data remain inconclusive, invasive endovenous therapy is increasingly favored in patients with extensive iliocaval or iliofemoral deep vein thrombosis (DVT) to reduce the rates of postthrombotic syndrome. Previously, pharmacomechanical thrombectomy was the therapy of choice, but the Inari ClotTriever device is an appealing, purely mechanical, alternative. It may reduce bleeding risk, intensive care unit admission, and the need for multiple procedures when compared with traditional thrombolysis. We present a series of 18 patients treated with the ClotTriever for extensive iliocaval or iliofemoral DVT. The Inari ClotTriever is a percutaneous mechanical thrombectomy system consisting of an expandable nitinol collection bag that is dragged along the vein wall, separating and capturing thrombus for collection into the retrieval sheath. We retrospectively reviewed all patients undergoing ClotTriever thrombectomy since the device became available at our quaternary referral center in June 2019. The review of these patients' records was determined to be exempt by our institutional review board. Eighteen patients underwent ClotTriever thrombectomy between June 2019 and November 2021. Most patients (N=16, 89%) presented within 2weeks of symptom onset, and identifiable provoking factors were present in all patients. The most common provoking factor was anatomy, with May-Thurner syndrome present in 8 patients. All patients had restoration of unimpeded venous flow in the treated segments, although 3 had some residual nonflow limiting thrombus. There were no bleeding events or repeat venous procedures. The median postprocedure length of stay of 2days. Postoperative venous imaging was performed in 15 patients and showed patency of the treated segment in 14 patients. Revised Clinical Venous Severity Scores were available in 14 patients during the course of follow-up. Of these, 9 patients' highest scores were 0, 2 patients' highest scores were 2, 2 patients' highest scores were 4, and 1 patient had a high score of8. Venous flow was re-established in all 18 patients treated with the ClotTriever in this series, with no bleeding complications, and median postprocedure length of stay of 2days. All patients with available follow-up, except 1, retained patency of the treated venous segments, and most had mild postthrombotic syndrome or none at all. These findings suggest that the ClotTriever is a safe and effective way to treat extensive iliocaval/femoral DVT.

Safety and Efficacy of the Treatment of Iliofemoral Deep Vein Thromboses With the Inari ClotTriever

Safety and Efficacy of the Treatment of Iliofemoral Deep Vein Thromboses With the Inari ClotTriever

How Prior History of Deep Vein Thrombosis Influences Iliac Vein Stenting

We observed that a history of deep vein thrombosis (DVT) was more prevalent than expected among patients undergoing iliofemoral vein stent placement for nonthrombotic iliac vein lesion (NIVL), of which May-Thurner syndrome is the most common. We undertook this study to understand how prior DVT affects perioperative outcomes among these patients.

Synergistic Effect of May–Thurner Syndrome and COVID-19

May–Thurner syndrome (MTS) is also called Cockett syndrome or iliocaval syndrome is described as compression of the left iliofemoral vein by the right common iliac artery against the vertebral body. We present a rare case of MTS in a 31-year-old female in the left lower extremity complicated after COVID-19. Screening magnetic resonance imaging pelvis showed compression of left common iliac vein by right common iliac artery over L5 lumbar vertebra suggestive of MTS. Findings were confirmed by a lower limb computed tomography venogram. A high degree of clinical suspicion of COVID-19 post sequela is needed for early diagnosis in this era.

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

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). 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. Of the 311 patients analyzed, 66.6% (n=207) were female. The mean lumbar vertebral body-iliac artery distance (LVBIAD) was 7.2mm, whereas the mean LCIVD was 8.5mm; both were higher in men (P<0.001). The statistical analysis of LVBIAD and LCIVD distributions revealed no normality pattern (P<0.05). 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=0.884). The LVBIAD was <5mm and <3mm 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.

Criteria to predict midterm outcome after stenting of chronic iliac vein obstructions (PROMISE trial)

BackgroundEndovenous stent placement has become a first-line approach to prevent post-thrombotic syndrome in patients with chronic post-thrombotic obstruction (PTO) or nonthrombotic iliac vein lesions if conservative management fails. This study aims to identify factors associated with loss of patency to facilitate patient selection for endovenous stenting. MethodsWe retrospectively analyzed 108 consecutive patients after successful endovenous stenting for chronic vein obstruction performed at a single institution from January 2008 to July 2020. Using multivariable logistic regression, we explored potential predictive factors for loss of stent patency, including baseline demographics, post-thrombotic changes, and peak flow velocities measured in the common femoral vein (CFV), deep femoral vein, and femoral vein (FV) using duplex ultrasound examination. ResultsThe mean follow-up duration was 41 ± 26 months, and participants had a mean age of 47.4 ± 15.4 years with 46.3% women. Ninety (83.3%) patients had PTO and 18 (16.7%) had nonthrombotic iliac vein lesions, predominantly due to May-Thurner syndrome. Loss of patency occurred in 20 (18.5%) patients, all treated for PTO. Comorbidities, side of intervention, and sex did not differ between patients with occluded and patent stents. Stent occlusion was more common with increasing number of stents implanted (P < .001) and with distal stent extension into and beyond the CFV (P < .001). Preinterventional predictive factors for stent occlusion were lower duplex ultrasound peak velocity in the CFV (odds ratio [OR]: 7.52, 95% confidence interval [CI]: 2.54-22.28; P < .001) and FV (OR: 10.75, 95% CI: 2.07-55.82; P < .005), and post-thrombotic changes in the deep femoral vein (OR: 4.51, 95% CI: 1.53-13.25; P = .006) and FV (OR: 3.62: 95% CI: 1.11-11.84; P = .033). Peak velocities of ≤7 cm/s (interquartile range: 0-20 cm/s) in the CVF and ≤8 cm/s (interquartile range: 5-10 cm/s) in the FV were significantly associated with loss of patency. ConclusionsInsufficient venous inflow as assessed by low peak velocities in the CFV and FV as well as post-thrombotic findings represent reliable risk predictors for stent occlusions, warranting their inclusion into the decision-making process for invasive treatment of PTO.

Ilio-femoral venous thrombosis in a young patient? Think of May-Thurner Syndrome!

Ilio-femoral venous thrombosis in a young patient? Think of May-Thurner Syndrome!

Lethal hemorrhage from iliac vein rupture complicating inferior vena cava thrombosis demonstrated by post-mortem CT angiography.

Spontaneous iliac vein rupture is a rare cause of retroperitoneal hemorrhage that may present to the forensic pathologist. It has been reported in association with venous thrombosis, anatomical variants such as May-Thurner syndrome, and as a complication of a long-term indwelling IVC filter. It has a female predominance and most often occurs due to rupture of the left iliac vein. This is the first report of the use of post-mortem computed tomography (PMCT) and post-mortem computed tomography angiography (PMCTA) as an adjunct to a conventional autopsy to diagnose rupture of the left iliac vein causing retroperitoneal hemorrhage arising as a complication of an inferior vena cava (IVC) thrombus. We discuss the use of PMCTA as a useful tool in the diagnosis of vascular injury and how it can be used to assist the forensic pathologist. The use of PMCT with PMCTA is an invaluable adjunct to conventional autopsy to diagnose the site of vascular rupture.

Case Report of May-Thurner Syndrome Identified on Abdominal Ultrasound

Case Report of May-Thurner Syndrome Identified on Abdominal Ultrasound

A rare case of left inferior vena cava presenting with May-Thurner syndrome

BackgroundMay–Thurner anomaly is characterized as external venous compression by the arterial framework against hard bony structures. This chronic anatomical lesion infrequently leads to deep vein thrombosis in the lower extremity, and it may lead to leg swelling as a long-term post-thrombotic complication. Left iliac vein compression may not be as uncommon as was previously thought, and it typically occurs in women more than men. Congenital anomalies of venous tree are not rare; they exist in 8.7% of the general population.Case-presentationWe herein present the first case of right-sided May Thurner Syndrome in a patient with IVC anomalies. In our patient, both common iliac veins formed the left-sided IVC, which extended to the hemiazygos vein and the superior vena cava. Additionally, there was a right-sided suprarenal IVC, which extended to the right atrium.ConclusionUnderstanding the proper anatomy in May-Thurner syndrome helps in better decision making for management of disease pathophysiology.

A Case Report of May-Thurner Syndrome Identified on Abdominal Ultrasound.

May-Thurner Syndrome, leg swelling, POCUS, ultrasound, deep venous thrombosis.

Trans-abdominal Color Doppler US versus Direct Multi-detector Computed Tomography Venography in the Diagnosis of May-Thurner Syndrome

Trans-abdominal Color Doppler US versus Direct Multi-detector Computed Tomography Venography in the Diagnosis of May-Thurner Syndrome

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

To explore the etiology of May-Thurner syndrome (MTS) with acute iliofemoral deep vein thrombosis (DVT) regarding imaging findings and clinical features. We retrospectively analyzed 57 patients with acute left iliofemoral DVT from 2015 to 2020. The diameter of left common iliac vein (LCIV) at the maximal compression site and its percent compression regarding the average diameter of the uncompressed iliac vein were recorded in central and distal portions of the LCIV according to the location in the quadrant of lumbar vertebral body. Compression was categorized into simple and bony MTS; Simple MTS as LCIV compressed by the right common iliac artery (RCIA) versus Bony MTS as LCIV by lower lumbar degenerative changes regardless of RCIA compression. Initial computed tomographic venography (CTV) regarding chronic change of LCIV such as fibrotic atrophy or cordlike obliteration, extent of thrombus, and lumbar degenerative changes were evaluated. Therapeutic effect after initial therapy was assessed in follow-up CTVs after 3-6months. All patients showed LCIV compression with 19 simple MTS (mean age, 42.8 ± 14.1years [23-67years]; 12 females; symptom for 4.4 ± 5.5days) and 38 bony MTS (mean age, 73.0 ± 10.2years [49-85years]; 26 females; symptom for 5.5 ± 4.8days). There was significant difference in age (p < .001) and no significant difference in sex or symptom duration between two groups (p = .691 and 0.415, respectively). All simple MTS showed compression only in the central LCIV and half of bony MTS showed compression in both central and distal LCIV (p < .001). Among the lumbar degenerative changes, symmetric anterolateral osteophyte (p < .001) and asymmetric osteophyte (p < .001) were significantly associated with bony MTS, but not scoliosis (p = .799), compared to simple MTS. Although there was no significant difference in chronic change of LCIV, thrombosis extent, and therapeutic effect between two groups (p > .05), chronic change of LCIV showed significant difference between single and dual compression (23.7% vs. 57.9%, p = .024) and residual thrombus after initial therapy was occurred in 21.1% of single compression and 47.4% in dual compression with non-significant trend (p = .082). Bony MTS related to lumbar degenerative changes with acute iliofemoral DVT occurs in older patients, presenting more than one stenosis at LCIV, inducing more chronic change with possibly weaker therapeutic effect than simple MTS.

May-Thurner Syndrome and Lymphedema Reconstruction.

Background:May-Thurner syndrome (MTS) is an anatomical variant that results in compression of the left common iliac vein by the right common iliac artery. Although often asymptomatic, lower extremity swelling/edema, deep venous thrombosis, post-thrombotic syndrome, and eventual lymphedema (due to long-standing venous obstruction) can develop. The clinical management of patients presenting for lymphedema surgery with concomitant or undiagnosed MTS is not well described.Methods:This review investigates two patients who were evaluated for unilateral lower extremity lymphedema, both of whom were subsequently diagnosed with MTS. Standard imaging (including lymphoscintigraphy, indocyanine green lymphangiography, and magnetic resonance venography) were performed to identify proximal venous obstruction. Treatment was accomplished using vascular surgical management, including stenting of the iliac vein before lymphedema reconstruction with vascularized lymph node transfer and multiple lymphovenous bypass.Results:Both patients we examined in this review had improvement of lymphedema with vascular surgical management. Literature review reveals that MTS has an incidence as high as 20% in the population, although commonly unidentified due to lack of symptomatology.Conclusions:There are no studies documenting the incidence of MTS in patients referred for lymphedema surgical management. Routine studies should be obtained to screen for proximal venous obstruction in patients presenting for surgical management of lower extremity lymphedema. Additional research is needed regarding the approach to managing patients with both MTS and lymphedema. Careful observational and prospective studies may elucidate the appropriate time interval between venous stenting and lymphedema microsurgical reconstruction.

Abstract No. 534 Effects of lumbar spine construct and movements in May-Thurner syndrome using a detailed Finite Element Model (FEM)

The pathological understanding and medical management of May-Thurner Syndrome (MTS) has progressed significantly over time. However, there remains a paucity of data on diagnostic criteria and patient specific etiology to guide clinical management. The present abstract presents a biomechanics-based computational model to elucidate the cause of common iliac vein compression.

Abstract No. 394 May-Thurner iliac venous compression and clinical presentation with evaluated with 4D Flow MRI

May-Thurner Syndrome (MTS) is caused by compression of the left common iliac vein (LCIV). While imaging findings and clinical manifestations may be associated, these relationships are complex. We aimed to determine whether hemodynamic significance of LCIV compression and related clinical manifestations could be assessed by measuring the relative blood flow in the proximal LCIV and proximal right common iliac vein (RCIV). 4D Flow MRI quantified LCIV and RCIV blood flow and LCIV/RCIV flow ratio was calculated in patients with LCIV compression compared with control patients with no vascular abnormalities (NVA).

Abstract No. 23 Catheter-directed therapy for pediatric patients with deep venous thrombosis and underlying May-Thurner syndrome

Some pediatric patients develop left lower extremity deep venous thrombosis (DVT) due to May-Thurner syndrome (MTS), an anatomical variant in which the right common iliac artery compresses the left common iliac vein against the lumbar spine. This case series seeks to document endovascular therapy, including catheter-directed thrombolysis/pharmaco-mechanical thrombectomy (CDT) and venous stenting for this subpopulation, which is underreported in current literature.