Re-evaluation of iliac compression syndrome using magnetic resonance imaging in patients with acute deep venous thromboses

Three-Year Outcomes, Risk Factors for Restenosis After Stenting for DVT Combined with Iliac Vein Compression Syndrome

This study aimed to evaluate the safety and efficacy of pharmacomechanical catheter-directed thrombolysis (PCDT) and stenting for treating acute iliofemoral deep venous thrombosis (DVT) combined with iliac vein compression syndrome (IVCS), and to identify the predictors of stent restenosis. Patients with acute proximal DVT combined with IVCS underwent PCDT and stenting from January 2017 to December 2022 were enrolled. Primary and secondary patency were assessed by duplex ultrasound (DUS). The morbidity of postthrombotic syndrome (PTS) was assessed by the Villalta score. Risk factors for stent restenosis were assessed using univariate and multivariate Cox regression models. Total of 254 patients were included. The mean follow-up time was 36.06 ± 17.66 months. The primary patency rates at 1 year, 3 years, and 5 years were 92.5%±1.7%, 85.4%±2.4%, and 82.4%±2.9%, respectively. The incidence of stent restenosis was 14.2%. Discontinuation of anticoagulants within one year [hazard ratio (HR) = 5.03; P = .048] was the factor associated with acute in-stent thrombosis. Previous DVT history (HR =2.29; P = .037) and stent placement across the inguinal ligament (HR =6.70; P < .001) were identified as independent risk factors significantly associated with stent restenosis. The overall PTS rate was 19.3%. PCDT with stenting is safe and effective for patients with iliofemoral DVT secondary to IVCS, leading to low rates of PTS. Previous DVT history and stents placed across the inguinal ligament may be predictors of stent restenosis. Furthermore, stent restenosis typically occurs within one year and is mainly caused by acute thrombosis due to discontinuation of anticoagulants.

Venous anomalies and thromboembolism

Patients with venous anomalies are at increased risk of developing venous thromboembolism (VTE) and subsequent complications, but they are often under-recognised. While unprovoked VTE may trigger testing for inherited thrombophilias and malignancy screening, anatomic variants are considered less often. Venous anomalies increase the risk due to venous flow disturbance, resulting in hypertension, reduced flow velocity and turbulence. Recognition is important as endovascular or surgical intervention may be appropriate, these patients have a high rate of VTE recurrence if anticoagulation is ceased, and the anomalies can predispose to extensive VTE and severe post-thrombotic syndrome (PTS). In this case series, we present representative cases and radiological images of May-Thurner syndrome (MTS), inferior vena cava (IVC) variants and venous aneurysms, and review the available literature regarding optimal diagnosis and management in each condition.

Back Pain and Right Leg Swelling: Unusual Presentations of May-Thurner Syndrome

May-Thurner (MT) syndrome refers to compression of the left common iliac vein by the right common iliac artery. Symptoms reported are generally left-sided leg swelling or pain. It is unusual for patients to report right-sided symptoms that are alleviated by treating MT compression. This case series describes three patients who had right-sided symptoms caused by left-sided venous compression. A retrospective chart review identified three patients over a year who presented with a variety of symptoms, including right-leg pain and swelling, and underwent treatment with left-sided venous compressions with a resolution of symptoms. Three patients were identified with right-sided back and flank pain. Venography with intravascular ultrasound (IVUS) showed the MT compression was greater than 75% in each case (mean 80.3% with a range of 75.7%-95%), and all patients were treated by decompressing the venous outflow obstruction by stenting the left common iliac vein, which relieved their symptoms. Venous compressions that occur on the anatomical left side can lead to right-sided symptoms. In patients reporting right-sided back and flank pain, MT should be considered in the differential diagnosis.

[Endovascular Therapy of Chronic Iliofemoral Venous Outflow Obstructions]

Deep vein thrombosis (DVT) is associated with a high cost burden for health care systems because of secondary cost intensive complications like pulmonary embolism and especially the post thrombotic syndrome (PTS). Current standard therapy of anticoagulation for DVT therapy has not changed through the years leaving patients especially with iliofemoral vein thrombus on a high-risk situation for developing PTS. For patients with chronic venous outflow obstruction of the iliac vein system dedicated venous stents and recanalization techniques are today available.

Neue Therapien akuter und chronischer Beckenvenenobstruktionen

Die Inzidenz der tiefen Venenthrombose (TVT) beträgt in Westeuropa 1/1000 Einwohner pro Jahr. Je nach Lokalisation und Ausdehnung der TVT entwickeln 20–83% der Patienten ein postthrombotisches Syndrom trotz einer optimalen Antikoagulation und Kompressionstherapie. Endovaskuläre Thrombektomieverfahren mit Wiedereröffnung der iliofemoralen venösen Strombahn haben das Ziel, mittel- und langfristig ein postthrombotisches Syndrom zu vermeiden. Bei Patienten mit chronischen V.-cava- und Beckenvenenverschlüssen stehen heutzutage spezielle Rekanalisationstechniken mit Einsatz von speziellen venösen Stents zur Verfügung.

Endovascular Intervention for May-Thurner Syndrome in a Pregnant Patient with a Patent Foramen Ovale and Paradoxical Embolism

May-Thurner syndrome (MTS) is a known structural risk factor for deep vein thrombosis (DVT) and embolism. In patients with a patent foramen ovale (PFO), emboli originating from the deep veins are able to paradoxically reach the systemic circulation via the PFO, consequently resulting in transient ischemic attacks (TIA) or stroke.We report the case of a 31-year-old pregnant woman, with a recent history of TIA, who presented with chronic bilateral numbness, pain, and swelling in the lower extremities. On imaging, she was found to have a PFO and MTS. Her pregnancy was subsequently terminated. This decision was made independently by the patient. Her care team did not advise her to terminate her pregnancy as there was no specific medical reason to do so. However, the patient was in significant physical pain and distress and ultimately was not comfortable continuing with the pregnancy. This highlights the complex, multifactorial decision-making process that pregnant patients with comorbid health conditions undertake. The patient then underwent transcatheter PFO closure and stents were placed bilaterally in the left and right common iliac veins. Following the stent procedure, lower extremity symptoms swiftly resolved, allowing the patient to significantly improve her ability to ambulate. There have been no signs of TIA since her procedures, and her venous symptoms have been stable.In patients with TIA or stroke from a paradoxical embolism, MTS should be considered as a potential etiology. Endovascular intervention to treat the underlying MTS should also be considered to decrease the risk of recurrent DVT and embolism.

Non-enhanced multimodal magnetic resonance imaging in assessment of iliac vein obstruction with or without thrombosis

OBJECTIVE

To evaluate the diagnostic accuracy of a contrast-free multimodal magnetic resonance (MR) protocol (including M2DIPEAR, THRIVE, BTFE-SPAIR, and FLAIR sequences) in the detection of iliac vein obstruction with or without thrombosis.

MATERIALS AND METHODS

From May 1st, 2015, to May 1st, 2016, a total of 73 patients (aged 51.33 ± 4.21 years) who received both digital subtraction angiography (DSA) and the multimodal MR imaging were included. The protocol of the multimodal MR included M2DIPEAR and BTFE-SPAIR for presenting iliac vein obstruction, and THRIVE and FLAIR for revealing the co-existed thrombosis. Three observers who were blinded to clinical and DSA results independently analyzed all multimodal MR datasets. Per-patient evaluations on presence or absence of iliac vein obstruction were performed to calculate the diagnostic performance of MR imaging (DSA regarded as gold reference) in terms of overall accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV). Capability to display the co-existing venous thrombus was also evaluated per-MR sequence using a 3-point scale system.

RESULTS

Iliac vein obstruction was depicted with DSA in 64 patients. In per-patient evaluation, the multimodal MR imaging yielded accuracy of 95.9% (70/73), sensitivity of 96.9% (62/64), specificity of 88.9% (8/9), positive predictive value of 98.4% (62/63), and negative predictive value of 80% (8/10), respectively. In the multimodal MR sequences, balanced turbo field echo-spectral attenuated inversion recovery (BTFE-SPAIR) sequence was superior to other sequences in depicting the iliac vein configuration, but fluid attenuated inversion recovery (FLAIR) and T1 high-resolution isovolumetric examination (THRIVE) seemed superior in detecting co-existing venous thrombosis.

CONCLUSIONS

M2DIPEAR and BTFE-SPAIR sequence can reveal iliac vein obstruction while THRIVE and FLAIR can detect the co-existed thrombosis. The proposed multimodal MR protocol can accurately depict the iliac vein obstruction and accurately detect the co-existing venous thrombosis comparable with that of DSA.

Reduced External Iliac Venous Blood Flow Rate Is Associated with Asymptomatic Compression of the Common Iliac Veins

Background and Objectives: Compression of the common iliac veins (CIV) is not always associated with lower extremity symptoms. This study analyzed this issue from the perspective of patient venous blood flow changes using quantitative flow magnetic resonance imaging. Materials and Methods: After we excluded patients with active deep vein thrombosis, the mean flux (MF) and mean velocity (MV) of the popliteal vein, femoral vein, and external iliac vein (EIV) were compared between the left and right sides. Results: Overall, 26 of the patients had unilateral CIV compression, of which 16 patients had symptoms. No significant differences were noted in the MF or MV of the veins between the two sides. However, for the 10 patients without symptoms, the EIV MF of the compression side was significantly lower than the EIV MF of the non-compression side (p = 0.04). The receiver operating characteristic curve and chi-squared analyses showed that when the percentage difference of EIV MF between the compression and non-compression sides was ≤-18.5%, the relative risk of associated lower extremity symptoms was 0.44 (p = 0.016). Conclusions: If a person has compression of the CIV, a decrease in EIV blood flow rate on the compression side reduces the rate of symptom occurrence.

Magnetic Resonance Imaging Evaluation of Left Common Iliac Vein Compression in Patients With and Without Symptoms of Venous Disease

BACKGROUND

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.

CONCLUSIONS

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.

May-Thurner syndrome: History of understanding and need for defining population prevalence

Patients with May-Thurner syndrome (MTS) are at elevated risk of developing an extensive left iliofemoral deep vein thrombosis (DVT; localized blood clot) due to an anatomical variant where the right common iliac artery compresses the left common iliac vein against the lumbar spine. While MTS was initially presumed to be rare when it was first anatomically defined in 1957, case reports of this syndrome have recently become more frequent, perhaps due to improved imaging techniques allowing for enhanced visualization of the iliac veins. Still, the population burden of this condition is unknown, and there is speculation it may be higher than generally perceived. In the present review, we (a) review history of how MTS became recognized, (b) describe practical challenges of studying MTS in population-based settings due to the specialized imaging required for diagnosis, (c) discuss why the contribution of MTS to DVT may be underestimated, (d) describe uncertainty regarding the degree of venous compression which leads to DVT, and (e) outline future research needs. Our goal is to raise awareness of MTS and spark additional research into the epidemiology of this condition, which may be an underappreciated causative venous thromboembolism risk factor.

Standards for recanalisation of chronic venous outflow obstructions

Abstract. Postthrombotic syndrome (PTS) is the most common complication after iliofemoral deep vein thrombosis. It reduces quality of life and increases deep vein thrombosis (DVT)-related costs. The clinical symptoms and severity of PTS may vary; the most common symptoms include edema, pain (venous claudication), hyperpigmentation, lipodermatosclerosis, and ulceration. PTS is based on the principle of outflow obstruction, which may be caused by venous hypertension and may lead to valvular damage and venous reflux or insufficiency. Recent technical developments and new stent techniques now allow recanalisation of even complex venous outflow obstructions within the iliac vein and the inferior vena cava. This manuscript gives an overview on the latest standards for venous recanalisation.

The Midterm Effect of Iliac Vein Stenting following Catheter-directed Thrombolysis for the Treatment of Deep Vein Thrombosis

BACKGROUND

When following catheter-directed thrombolysis (CDT) for deep vein thrombosis (DVT), the stenosed iliac veins is controversy. To evaluate the mid-term outcomes of CDT with or without stent implantation for DVT in the presence of iliac vein compression.

METHODS

Seventy-three patients with iliac vein compression following CDT for acute lower extremity DVT from January 2009 to December 2014 were retrospectively analyzed. There were 32 males and 41 females, with average age of 53.57 ± 15.60 years (median: 45 years, range: 20-79 years). After CDT, patients with iliac vein compression were divided into 2 groups: the stenting group (n = 40) and the nonstenting group (n = 33). Patency rate of the deep vein, chronic change of vessels, clinical, etiological, anatomical, and pathological elements (CEAP) classification, venous clinical severity score, and Villalta scale were chosen to evaluate the midterm and long-term outcomes.

RESULTS

Eighty-eight limbs among the patients (58 unilateral and 15 bilateral) were followed with mean time of 38.38 ± 14.91 months. The difference in vein patency between 2 groups (85.17 ± 25.62 vs. 54.61 ± 40.42) was statistically significant (P < 0.05). According to the C in CEAP classification, the difference in clinical manifestations between the 2 groups was statistically significant (P < 0.05). In addition, the Villalta scale scores were also significantly different between the 2 groups (1.73 ± 2.86 vs. 4.39 ± 5.16, P < 0.05).

CONCLUSIONS

Stent implantation in severely stenosed iliac segments following CDT for lower extremity DVT increased the patency of deep veins and improved midterm quality of life compared with that of nonstenting.

Sonography’s Role in the Diagnosis of May–Thurner Syndrome

May–Thurner syndrome (MTS), also known as Cockett syndrome or iliac vein compression syndrome, is a condition in which patients develop swelling, deep vein thrombosis (DVT), venous insufficiency, and other symptoms of the left lower extremity due to an anatomic variant in which the right common iliac artery overlies and compresses the left common iliac vein against the lumbar spine. Although it is an uncommonly diagnosed condition, it is estimated to compose up to half of cases of left lower extremity venous disease. Although having some degree of iliac vein compression is considered a normal anatomic variant in an asymptomatic patient, those who experience severe swelling, venous reflux, and DVT often have anatomically abnormal veins with a spur formation. With proper technique and proficiency, transabdominal sonography can be used as a valuable diagnostic tool in the discovery and to facilitate treatment of May–Thurner syndrome. Diagnostic ultrasound also can monitor the development of recurring DVT and identify symptoms of postthrombotic syndrome.

Anatomic and clinical risk factors for pulmonary embolism in patients with deep venous thrombosis of the lower extremity

Purpose

Iliac vein compression is a known culprit of deep vein thrombosis (DVT). In contrast, the compression may prevent the pulmonary embolism (PE). The aim of this study was to evaluate the anatomic and clinical risk factors of PE in patients with lower extremity DVT.

Methods

PE was evaluated using chest computed tomography in patients with lower extremity DVT. The patients were classified into group I (DVT without PE) and group II (DVT with PE) and analyzed to clarify the anatomic and clinical risk factors associated with PE in patients with DVT. As the anatomic factor, the shortest length between the common iliac artery (CIA) and spinal body (SB) was measured. Statistical analyses utilized the multivariable logistic regression model, and receiver operating characteristic (ROC) curve analysis.

Results

We examined 114 patients (age; 62.7 ± 16.9 years, 41.7% men) with DVT with/without PE. The prevalence of concurrent DVT with PE was 52.6%. Blood tests showed no difference between the 2 groups. Of all the assessed patients' characteristics, only infection was significantly and independently associated with PE (P = 0.04). The shortest length between CIA and SB was 6.7 ± 3.5 mm in group I and 11.3 ± 3.7 mm in group II (P < 0.001). ROC curve analysis showed that 7.6 mm was the cut-off value for the anatomic risk of PE.

Conclusion

Infection was significantly associated with concurrent DVT and PE. The shortest length between CIA and SB (<7.6 mm) may prevent PE in patients with DVT.

Compression of the right iliac vein in asymptomatic subjects and patients with iliofemoral deep vein thrombosis

OBJECTIVE

To evaluate right iliac vein and left iliac vein compression in asymptomatic subjects, right-sided and left-sided iliofemoral deep vein thrombosis patients.

METHODS

A retrospective analysis of records and computed tomography images was conducted in 200 asymptomatic subjects (male:female, 100:100). A prospective analysis was conducted in 79 consecutive deep vein thrombosis patients (left:right deep vein thrombosis, 47:32) who had undergone contrast-enhanced computed tomography examination. The minor diameter and percentage compression of the iliac vein were evaluated.

RESULTS

In asymptomatic subjects, 13.5% had right iliac vein compression >50%, 2.0% had right iliac vein compression >70%, mean compression was 23.48%; 45.0% had left iliac vein compression >50% and 17.0% had left iliac vein compression >70%, mean compression was 47.58%. Right iliac vein sandwiched between the right external iliac artery and the right internal iliac artery was the most common compression pattern (59.26%). Males had higher right iliac vein compression than the females (male:female, 26.29%:20.68%, P < 0.001). Mean percentage compression of the right iliac vein was higher in right deep vein thrombosis patients than in left deep vein thrombosis patients (right:left deep vein thrombosis, 48.54%:22.29%, P < 0.001).

CONCLUSION

Similar to left iliac vein compression, right iliac vein compression was a frequent imaging finding in CT and represented a normal anatomic pattern. Right deep vein thrombosis patients had more serious right iliac vein compression than left deep vein thrombosis patients, and further research is required on the association of right iliac vein compression with right iliofemoral deep vein thrombosis.

CIRSE standards of practice guidelines on iliocaval stenting

Chronic venous insufficiency (CVI) as an advanced stage of chronic venous disease is a common problem that occurs in approximately 1-5 % of the adult population. CVI has either a nonthrombotic (primary) or postthrombotic (secondary) cause involving reflux, obstruction, or a combination of both. The role of venous obstruction is increasingly recognized as a major cause of CVI, with obstructive lesions in the iliocaval segment being markedly more relevant than lesions at the levels of the crural and femoral veins. Approximately 70-80 % of iliac veins develop a variable degree of obstruction following an episode of acute deep venous thrombosis. Nonthrombotic iliac vein obstruction also known as May-Thurner or Cockett's syndrome is the most common cause of nonthrombotic iliac vein occlusion. While compression therapy is the basis of therapy in CVI, in many cases, venous recanalization or correction of obstructive iliac vein lesions may result in resolution of symptoms. This document reviews the current evidence on iliocaval vein recanalization and provides standards of practice for iliocaval stenting in primary and secondary causes of chronic venous disease.

Iliac vein compression as risk factor for left- versus right-sided deep venous thrombosis: case-control study

PURPOSE

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).

MATERIALS AND METHODS

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.

RESULTS

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).

CONCLUSION

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.

SUPPLEMENTAL MATERIAL

http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.12111580/-/DC1.

"Right-sided" May-Thurner syndrome

The May-Thurner syndrome is a well-known anatomical anomaly where the left common iliac vein (LCIV) is compressed between the right common iliac artery and the fifth vertebral body. This report describes the case of a "right-sided" May-Thurner syndrome where the right common iliac vein (RCIV) is compressed by the left common iliac artery in a patient with a left-sided inferior vena cava (IVC). A 26-year-old woman was admitted to our institution with acute edema of the right lower limb. The diagnosis of May-Thurner syndrome was done by CT scan and confirmed by phlebography. An endovascular treatment with stenting was carried out, with good patency and clinical result at 12-month follow-up.

Symptomatic ileofemoral DVT after onset of oral contraceptive use in women with previously undiagnosed May-Thurner Syndrome

OBJECTIVE

May-Thurner syndrome is characterized by left common iliac obstruction secondary to compression of the left iliac vein by the right common iliac artery against the fifth-lumbar vertebra. This anatomic variant results in an increased incidence of left-sided deep venous thrombosis (DVT). Furthermore, while a preponderance of left-sided DVT has been demonstrated in women during pregnancy and oral contraceptive use, patients are not typically screened for this condition after developing a left-sided DVT. As anticoagulation alone is ineffective for DVT treatment in the setting of May-Thurner anatomy, more aggressive treatment is warranted. Failure to diagnosis this condition predisposes these women to the unnecessary risks of recurrent DVT and post-thrombotic syndrome.

METHODS

We present the occurrence of 7 adolescent patients with previously undiagnosed May-Thurner syndrome who presented with DVT after the initiation of oral contraceptive steroids (OCP) use. All 7 patients elected to proceed with mechanical thrombolysis/catheter based thrombolysis followed by endovascular stenting and were postoperatively treated with 6 months of warfarin.

RESULTS

Mean patient age was 18.3 +/- 3.3 years (range, 16-24 years). Mean time to presentation after initiation of OCP was 5 weeks (range, 2-10 weeks). Mean time to intervention was 16.8 days (range, 10-24 days). All patients were treated with mechanical thrombectomy. Our rate of intraoperative clot resolution was 100%. All 7 patients were treated with self expanding nitinol stents after angioplasty of the iliac vein stenosis with resolution of the stenotic segment. Primary stent patency is 100% (7/7). Mean follow-up time is 13 +/- 13.84 months (range, 6-42 months). There have been no long-term complications related to surgical treatment or anticoagulation. All 7 patients have experienced resolution of left leg swelling and pain and have no evidence of post-thrombotic syndrome or DVT recurrence to date.

CONCLUSIONS

Women on OCPs presenting with left-sided iliofemoral DVT should be screened for hypercoagulable disorders and underlying May-Thurner anatomy. Treatment of May-Thurner syndrome should include thrombolysis/thrombectomy and anticoagulation for current DVT in addition to angioplasty and stenting of the underlying obstruction.