May-Thurner Syndrome: Causes, Symptoms, Diagnosis, Treatment

Abstract:

May-Thurner Syndrome (MTS), also known as iliac vein compression syndrome, is a condition characterized by the compression of the left common iliac vein by the overlying right common iliac artery. This compression can lead to the development of blood clots, resulting in deep vein thrombosis (DVT) in the left leg. In this comprehensive blog post, we will delve into the details of May-Thurner Syndrome, including its causes, symptoms, diagnosis, and treatment options. By the end, you will have a clear understanding of this condition and how it can be effectively managed.

Introduction to May-Thurner Syndrome

May-Thurner Syndrome (MTS), also known as iliac vein compression syndrome, is a condition characterized by the compression of the left common iliac vein by the overlying right common iliac artery. This compression can lead to the development of blood clots, typically in the deep veins of the left lower limb. MTS is considered a significant risk factor for deep vein thrombosis (DVT) in the affected leg.

What is May-Thurner Syndrome?

• Definition and explanation of MTS:

May-Thurner Syndrome refers to the anatomical compression of the left common iliac vein by the right common iliac artery. The compression results in venous stasis, which can predispose individuals to the development of blood clots in the left lower limb.

• Brief history of the syndrome:

May-Thurner Syndrome was first described in 1957 by Drs. May and Thurner, who reported a case of left iliac vein compression associated with thrombosis. Since then, the condition has been recognized as an important cause of DVT.

• Prevalence and risk factors:

The exact prevalence of MTS is not well-established, but it is estimated to occur in approximately 20% of the population. The condition is more common in women, with a female-to-male ratio of about 3:1. Other risk factors for MTS include hormonal changes, such as pregnancy or the use of oral contraceptives, as well as anatomical variations in the venous system.

Causes and Mechanism

• Anatomy of the iliac veins and arteries:

The iliac veins and arteries are major blood vessels in the pelvis. The right common iliac artery typically crosses over the left common iliac vein, resulting in a region of compression where the two vessels overlap.

• Compression of the left common iliac vein:

In May-Thurner Syndrome, the compression of the left common iliac vein by the right common iliac artery can lead to chronic irritation and damage to the venous wall. This irritation, combined with reduced blood flow, increases the risk of blood clot formation.

• Role of hormonal changes and genetics:

Hormonal changes, such as increased estrogen levels during pregnancy or the use of oral contraceptives, can contribute to the development or worsening of MTS. There is also evidence to suggest a genetic component, as the condition can occur within families.

Symptoms and Clinical Presentation

• Common symptoms experienced by MTS patients:

The most common symptom of MTS is pain and swelling in the left lower limb. Patients may also experience leg fatigue, a feeling of heaviness, and skin discoloration. However, not all individuals with MTS develop symptoms.

• Differences between left and right leg symptoms:

Symptoms of MTS are typically limited to the left lower limb due to the compression of the left common iliac vein. The right leg is generally unaffected unless there is an underlying venous disorder.

• Chronic vs. acute symptoms:

MTS can present as either chronic or acute. Chronic MTS refers to persistent symptoms that gradually worsen over time, while acute MTS refers to the sudden onset of symptoms due to an acute thrombosis or blood clot in the affected vein.

Attitude vs. Gratitude: of May-Thurner Syndrome

• Deep vein thrombosis (DVT):

One of the most significant complications of MTS is the development of DVT in the left lower limb. The compressed and damaged venous system increases the risk of blood clot formation, which can potentially travel to the lungs and cause a pulmonary embolism.

• Post-thrombotic syndrome (PTS):

PTS is a long-term complication that can occur in individuals who have experienced a deep vein thrombosis (DVT) associated with May-Thurner Syndrome. It is characterized by chronic symptoms such as leg pain, swelling, heaviness, and skin changes in the affected limb. These symptoms can significantly impact the individual’s quality of life.

The development of PTS is thought to be related to the damage caused by the initial DVT, including venous valve dysfunction, venous reflux, and impaired blood flow. The chronic venous insufficiency resulting from these changes leads to the persistent symptoms seen in PTS.

• Pulmonary embolism risk:

May-Thurner Syndrome increases the risk of developing a pulmonary embolism (PE), which occurs when a blood clot from the lower limb travels to the lungs. If a blood clot breaks off from the iliac vein and reaches the pulmonary circulation, it can block the blood flow to the lungs, leading to potentially life-threatening consequences.

Prompt diagnosis and appropriate management of May-Thurner Syndrome are essential to reduce the risk of complications such as DVT, PTS, and pulmonary embolism. Treatment options may include anticoagulant medications to prevent clot formation, endovascular procedures to relieve venous compression, and lifestyle modifications to improve venous circulation.

Diagnosis of May-Thurner Syndrome

May-Thurner Syndrome (MTS) is a condition characterized by the compression of the left iliac vein by the right iliac artery, resulting in venous stasis and the potential development of deep vein thrombosis (DVT) in the left lower extremity. The diagnosis of MTS requires a comprehensive evaluation using various diagnostic techniques. This section will provide an overview of the diagnostic methods and considerations for May-Thurner Syndrome.

Medical History and Physical Examination

A thorough medical history and physical examination play a crucial role in the diagnosis of May-Thurner Syndrome. Important points to consider include:

• Importance of a thorough medical history: Gathering information about the patient’s symptoms, medical conditions, previous surgeries, and history of DVT or pulmonary embolism is essential. Additionally, assessing any risk factors for venous thromboembolism, such as obesity, immobility, hormonal therapy, or pregnancy, is important.
• Clinical signs and physical examination findings: Although the clinical signs of MTS can vary, some common findings include swelling, pain, or heaviness in the left leg. Skin discoloration, varicose veins, and collateral veins may also be observed. However, it is important to note that physical examination findings alone are not sufficient for a definitive diagnosis of MTS.
• Differential diagnosis considerations: May-Thurner Syndrome should be differentiated from other conditions that cause similar symptoms, such as DVT, chronic venous insufficiency, arterial disease, or musculoskeletal causes. A comprehensive evaluation should be conducted to rule out these potential conditions.

Imaging Techniques

Imaging techniques play a vital role in confirming the diagnosis of May-Thurner Syndrome. The following methods are commonly used:

• Ultrasound examination for initial screening: Doppler ultrasound is often the initial imaging modality used to evaluate the iliac veins. It can identify the presence of iliac vein compression, assess blood flow, and detect the presence of DVT. However, it may not provide detailed anatomical information and may require further imaging for confirmation.
• Computed tomography (CT) scan: CT scanning with intravenous contrast can provide detailed anatomical information about the iliac veins and help identify the compression of the left iliac vein by the right iliac artery. It can also evaluate for the presence of DVT and assess the severity of venous stenosis.
• Magnetic resonance imaging (MRI) with venography: MRI with contrast and venography can provide excellent visualization of the iliac veins and accurately assess the degree of venous compression. This technique is particularly useful when planning for endovascular intervention or stenting.

Other Diagnostic Tests

In addition to imaging techniques, several other diagnostic tests can aid in the diagnosis of May-Thurner Syndrome:

• D-Dimer blood test: D-Dimer is a marker of blood clot formation and breakdown. Elevated D-Dimer levels may suggest the presence of DVT, but it is a non-specific test and cannot confirm the diagnosis of MTS alone. However, it can be useful in combination with other diagnostic methods.
• Venous duplex ultrasound: This imaging technique combines B-mode ultrasound and Doppler ultrasound to assess the flow of blood in the veins. It can detect the presence of DVT and evaluate the hemodynamics of the iliac veins. Duplex ultrasound is commonly used in conjunction with other imaging modalities for a comprehensive evaluation.
• Contrast venography: Contrast venography involves injecting a contrast dye into the veins to visualize blood flow and detect any abnormalities. While this method provides detailed information, it is an invasive procedure and is typically reserved for cases where other imaging modalities have not provided a definitive diagnosis or when planning for endovascular intervention.

Classification Systems

To assess the severity of iliac vein compression and guide treatment decisions, several classification systems have been developed for May-Thurner Syndrome. These systems include:

• May-Thurner Syndrome grading systems: The most commonly used grading systems are the Cockett classification and the Villalta score. The Cockett classification grades the severity of iliac vein compression based on the extent of venous collaterals and the presence of DVT. The Villalta score assesses the clinical signs and symptoms of chronic venous disease, including pain, swelling, and skin changes.
• Determining the severity of iliac vein compression: The severity of iliac vein compression can be assessed based on the degree of stenosis or occlusion observed on imaging studies. Measurements of the narrowest point of the left iliac vein are taken, and the degree of stenosis is calculated as a percentage. This information helps guide treatment decisions and determine the appropriate intervention, such as angioplasty or stenting.

Treatment Options for May-Thurner Syndrome

May-Thurner Syndrome (MTS) is a condition characterized by the compression of the left iliac vein by the overlying right iliac artery. This compression can lead to the development of blood clots in the affected vein, known as deep vein thrombosis (DVT). The treatment options for May-Thurner Syndrome aim to relieve the compression, restore normal blood flow, and prevent further complications such as pulmonary embolism.

Conservative Management

Conservative management refers to non-invasive treatment options that are generally recommended as the initial approach for patients with May-Thurner Syndrome, particularly in cases where the symptoms are not severe or when the blood clots are small. These conservative measures may include:

• Compression stockings and leg elevation: Wearing compression stockings can help improve blood flow in the legs and reduce swelling. Elevating the legs above heart level when resting can also promote blood circulation.
• Lifestyle modifications and exercise: Maintaining a healthy lifestyle is important in managing May-Thurner Syndrome. Regular exercise, such as walking or swimming, can help improve blood circulation and prevent blood clots. It is advisable to avoid prolonged periods of sitting or standing.
• Medications for blood thinning: Anticoagulant medications, such as heparin or warfarin, may be prescribed to prevent further clot formation and promote the dissolution of existing blood clots. These medications work by inhibiting the clotting factors in the blood.

Catheter-Directed Thrombolysis

Catheter-directed thrombolysis is a minimally invasive procedure that involves the use of a catheter to deliver clot-dissolving medications directly to the site of the blood clot. This procedure has several steps and benefits, including:

• Procedure overview and benefits: Under image guidance, a catheter is inserted into the affected vein, and a clot-dissolving medication, such as tissue plasminogen activator (tPA), is administered directly into the clot. This allows for targeted and efficient dissolution of the clot, restoring normal blood flow. Catheter-directed thrombolysis can help relieve symptoms, prevent further clot propagation, and reduce the risk of long-term complications.
• Dissolving blood clots with medications: The clot-dissolving medication used during catheter-directed thrombolysis helps break down the blood clot by activating the body’s natural clot-dissolving mechanisms. This process is known as fibrinolysis.
• Risks and potential complications: Although catheter-directed thrombolysis is generally safe and effective, there are risks associated with the procedure. These risks include bleeding, infection, damage to the blood vessel, and allergic reactions to the medication. The procedure should be performed by experienced interventional radiologists or vascular surgeons to minimize the risks.

Angioplasty and Stenting

Angioplasty and stenting are procedures performed to alleviate the compression of the iliac vein and restore normal blood flow. These procedures involve the following steps:

• Balloon angioplasty to open the compressed vein: During balloon angioplasty, a catheter with a deflated balloon at its tip is inserted into the compressed vein. The balloon is then inflated, expanding the narrowed portion of the vein and improving blood flow. The balloon is then deflated and removed.
• Placement of a stent to maintain vein patency: In some cases, after balloon angioplasty, a stent may be inserted to help keep the vein open. The stent is a small, mesh-like tube that provides structural support and prevents the vein from collapsing or becoming compressed again. Stents used in May-Thurner Syndrome are typically made of metal alloys or synthetic materials and are designed to be permanent implants.
• Success rates and long-term outcomes: Angioplasty with stenting has shown favorable success rates in relieving the compression of the iliac vein and improving blood flow. Studies have demonstrated that the majority of patients experience significant symptom relief and a reduction in the risk of recurrent DVT. However, long-term outcomes can vary depending on factors such as the extent of venous disease and individual patient characteristics. Regular follow-up visits and adherence to post-procedure care guidelines are essential to ensure the long-term effectiveness of angioplasty and stenting.

Surgical Options

In cases where conservative management or minimally invasive procedures are not sufficient or feasible, surgical interventions may be considered for the treatment of May-Thurner Syndrome. The surgical options include:

• Vein bypass surgery: Vein bypass surgery involves creating a new pathway for blood flow by bypassing the compressed segment of the iliac vein. This procedure typically involves using a synthetic graft or a segment of the patient’s own vein to create the bypass. Vein bypass surgery may be recommended for patients with extensive venous disease or when other treatment options have failed.
• Endovenous laser or radiofrequency ablation: These minimally invasive procedures are used to treat underlying venous insufficiency associated with May-Thurner Syndrome. They involve the use of laser or radiofrequency energy to heat and seal the affected vein, redirecting blood flow to healthier veins. These procedures can help alleviate symptoms, improve blood circulation, and reduce the risk of further complications.
• Thrombectomy for extensive clot removal: In cases where there are extensive blood clots or acute iliofemoral DVT, a surgical procedure called thrombectomy may be performed. Thrombectomy involves the removal of the blood clot from the affected vein to restore normal blood flow. This procedure is typically performed by vascular surgeons and may be combined with other treatment options, such as angioplasty or stenting.

Prevention and Prognosis of May-Thurner Syndrome

May-Thurner Syndrome (MTS) is a condition characterized by the compression of the left iliac vein by the overlying right iliac artery. This compression can lead to the development of deep vein thrombosis (DVT) in the left lower extremity. While MTS can be challenging to prevent due to its anatomical nature, there are measures that can be taken to reduce the risk of its occurrence and manage the condition effectively. This section will discuss lifestyle measures, recognizing risk factors, prognosis and long-term management, as well as patient education and support in relation to May-Thurner Syndrome.

Lifestyle Measures

• mportance of regular exercise and movement: Regular exercise, particularly activities that promote leg movement, can help improve blood circulation and reduce the risk of developing blood clots. Activities such as walking, swimming, and cycling are beneficial for maintaining healthy blood flow.
• Maintaining a healthy weight: Obesity and excess weight can put additional pressure on the veins, potentially exacerbating the compression caused by May-Thurner Syndrome. Maintaining a healthy weight through a balanced diet and regular exercise can help reduce the strain on the veins.
• Avoiding prolonged periods of sitting or immobility: Prolonged periods of sitting or immobility can increase the risk of developing blood clots. It is important to take frequent breaks, especially during long trips or sedentary activities, to stretch the legs and promote blood circulation.

Recognizing Risk Factors

• Identifying genetic predisposition: Some individuals may have a genetic predisposition to developing May-Thurner Syndrome. It is important to be aware of any family history of blood clotting disorders or venous conditions, as this may indicate an increased risk.
• Addressing hormonal changes in women: Hormonal changes, such as those that occur during pregnancy or while taking hormonal contraceptives, can contribute to the development of blood clots. Women should be cautious and discuss the potential risks with their healthcare provider.
• Understanding the relationship with pregnancy: Pregnancy can increase the risk of developing May-Thurner Syndrome due to the physiological changes that occur during this period. Healthcare providers should monitor pregnant women for signs of DVT and provide appropriate preventive measures.

Prognosis and Long-Term Management

• Prognostic factors for May-Thurner Syndrome: The severity of May-Thurner Syndrome can vary among individuals. Factors such as the extent of vein compression, the presence of blood clots, and associated symptoms can influence the prognosis. Timely diagnosis and appropriate treatment are crucial for managing the condition effectively.
• Long-term follow-up and monitoring: After initial treatment, individuals with May-Thurner Syndrome should undergo regular follow-up appointments with their healthcare provider. This helps monitor the progression of the condition, identify any recurrence of blood clots, and assess the effectiveness of preventive measures.
• Potential recurrence and prevention strategies: While treatment can alleviate the immediate symptoms and address the blood clot, there is a risk of recurrence. To minimize this risk, individuals may be advised to continue lifestyle modifications, use compression stockings, and consider anticoagulant medications or other preventive measures as prescribed by their healthcare provider.

Patient Education and Support

• Importance of patient education: Patients should be educated about the nature of May-Thurner Syndrome, its risk factors, and preventive measures. Understanding the condition empowers patients to actively participate in their own care and make informed decisions.
• Resources and support groups for MTS patients: There are various resources available to support individuals with May-Thurner Syndrome, including online communities, support groups, and patient advocacy organizations dedicated to venous disorders. These resources provide a platform for individuals to connect with others who share similar experiences, seek advice, and access educational materials.
• Coping strategies and lifestyle adjustments: Living with May-Thurner Syndrome may require certain lifestyle adjustments to manage the condition effectively. Patients can learn coping strategies such as practicing stress management techniques, elevating the legs when resting, and wearing compression stockings as recommended by their healthcare provider. These strategies can help alleviate symptoms and improve overall quality of life.

Conclusion

May-Thurner Syndrome is a condition that can have significant implications for individuals, particularly in terms of deep vein thrombosis and its associated complications. Understanding the causes, symptoms, diagnosis, and treatment options is crucial in effectively managing this syndrome. By implementing preventive measures and seeking appropriate medical care, individuals with May-Thurner Syndrome can experience improved outcomes and quality of life.

Glossary:

• Compression: The application of pressure or squeezing force on an object or body part.
• Deep vein thrombosis (DVT): The formation of a blood clot within a deep vein, typically in the legs.
• Post-thrombotic syndrome (PTS): A condition that occurs as a result of chronic damage to veins following a deep vein thrombosis.
• Pulmonary embolism: A potentially life-threatening condition where a blood clot travels to the lungs and blocks blood flow.
• Iliac veins and arteries: Blood vessels located in the pelvic region responsible for carrying blood to and from the legs.
• Differential diagnosis: The process of distinguishing between two or more conditions with similar symptoms to identify the correct diagnosis.
• Venography: An imaging technique that uses contrast material to visualize veins.
• D-Dimer: A blood test used to detect the presence of blood clots.
• Angioplasty: A procedure to widen narrowed or blocked blood vessels.
• Stent: A small mesh tube used to prop open a narrowed or collapsed vein or artery.
• Thrombectomy: The surgical removal of a blood clot.
• Endovenous laser or radiofrequency ablation: Minimally invasive procedures that use heat to seal off and close varicose veins.
• Prognostic factors: Factors that help predict the likely outcome or course of a disease or condition.

Last worded from Author

Remember, staying informed and proactive is key in managing May-Thurner Syndrome. By understanding the condition and seeking appropriate care, you can take control of your health and enjoy a better quality of life.

FAQs

Reference

(1) May-Thurner Syndrome – UPMC Heart and Vascular Institute. https://www.upmc.com/services/heart-vascular/conditions-treatments/may-thurner-syndrome.

(2) May–Thurner syndrome – Wikipedia. https://en.wikipedia.org/wiki/May%E2%80%93Thurner_syndrome.

(3) May-Thurner Syndrome Article – StatPearls. https://www.statpearls.com/articlelibrary/viewarticle/55124/.

(5) May-Thurner syndrome | Radiology Reference Article | Radiopaedia.org. https://radiopaedia.org/articles/may-thurner-syndrome-2.

(6) May-Thurner syndrome – PMC – National Center for Biotechnology Information. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8569277/.