May-Thurner Syndrome
Ashley Davis
Baker College of Auburn Hills
VAS 233

May-Thurner Syndrome can also be known as the iliac vein compression, iliocaval compression syndrome, or cockett syndrome. This is a rare condition in which the left iliac vein is compressed by the right iliac artery due to the artery crossing over the vein. May-Thurner Syndrome was first noted in 1957 when an anatomical variant was found by R May and J Thurner (Weerakkody, Y., n.d.). Most patients are asymptomatic and go unrecognized until the symptoms develop. This disease compromises the venous return and can cause a deep venous thrombosis but fortunately can be treated and prevented. May and Thurner suggested that the constant pulsations from the right iliac artery led to the development of a “spur”, which can also be called a venous lesion, in the vein wall which would result in venous obstruction. About 2 to 5% of all individuals suffering from a vein disorder in the lower extremities have been diagnosed with May-Thurner syndrome (4 Important Things You Need to Know About May-Thurner Syndrome, n.d.). There are no facts as to why this condition happens except being thought as a congenital defect. Although it can happen because of trauma, age and extreme weight gain. This disorder is common among young women between 20 and 40 years of age.
May-Thurner syndrome can cause left iliofemoral deep venous thrombosis. The patients will complain of unilateral swelling and pain. About 18-49% of patients with a left lower extremity deep venous thrombosis has been diagnosed with May-Thurner Syndrome (Al-Nouri, O., 2011). Many patients who have had this condition for a while can present with skin color changes, varicose veins, constant leg pain, phlebitis and skin ulcers from this chronic syndrome. If the blood clot (deep venous thrombosis) breaks away, it can become a pulmonary embolism and produce symptoms like shortness of breath, coughing with blood, and tachycardia.
According to Vascular Disease Management, May-Thurner Syndrome has 3 stages (2011). Stage 1 is when the patient is asymptomatic due to the iliac vein compression. Stage 2 is the development of venous “spur”. Stage 3 is the development of left iliac vein deep venous thrombosis. There are several variants of May-Thurner Syndrome that have been identified including compression of the left common iliac vein by the left internal iliac artery, compression of the right common iliac vein by the right internal iliac artery, compression of the inferior vena cava by the right common iliac artery and right-sided May-Thurner syndrome in a patient with a left sided inferior vena cava (Al-Nouri, O., 2011).
Unfortunately, May-Thurner syndrome is not the easiest to diagnose. Doppler ultrasound will be able to diagnose a deep venous thrombosis but is unable to identify is there is an iliac vein compression. To identify if the iliac vein compression syndrome a computed tomography (CT), CT venography, magnetic resonance venography (MRV), and intravenous ultrasound, or a conventional venography can be preformed. The traditional gold standard for diagnosing May-Thurner Syndrome is conventional venography. This technique uses a special dye that is injected into the vein prior to taking x-ray images. This procedure will reveal any areas of compression or sluggish blood flow (4 Important Things You Need to Know About May-Thurner Syndrome, n.d.). Treatment for May-Thurner syndrome is to prevent the compression and development of thrombosis. May-Thurner syndrome will only be treated when it is symptomatic. The most common treatment for a deep venous thrombosis is administration of anticoagulants. If the clot needs to be removed, thrombolysis or thrombectomy will be preformed. A stent is always going to be placed into the vein at the exact location of the compression. This stent is placed to keep the vein open and to prevent any future blood clots from the compression of the artery. Patients who have a high risk for deep venous thrombosis, will undergo placement of an IVC filter. It has been found that patients who have had a thrombectomy had a patency rate of 95% to 100% at a 2 year follow-up (Kalu, S., 2013). According to University of Virgina Health System’s Heart & Vascular Center, there are some other treatments that can be done. One treatment is a bypass surgery, in which the blood flow is rerouted around the vein. Another treatment is building a tissue “sling”, which is when tissue is surgically placed between the left common iliac vein and the right common iliac artery to lift the artery so it no longer puts pressure on the vein (May-Thurner Syndrome, n.d.). R May and J Turner were among the first to diagnose May-Thurner Syndrome. Although many new forms of May-Thurner have come about, the most common is still the left iliac vein being compressed by the right iliac artery. The syndrome is becoming more common in patients with an iliofemoral venous thrombosis. Endovascular stent placement is becoming the primary treatment as well as early recognition and aggressive management. If this diagnosis is missed, thrombosis will continue to occur. It is important to remember this as a differential diagnosis when a patient presents with unilateral symptoms and possible deep venous thrombosis.

References
4 Important Things You Need to Know About May-Thurner Syndrome. (n.d.). Retrieved May 19, 2016, from http://www.veindirectory.org/article/conditions/may-thurner-syndrome
Al-Nouri, O. (2011, March 8). May-Thurner Syndrome. Retrieved May 19, 2016, from http://www.vasculardiseasemanagement.com/content/may-thurner-syndrome
Kalu, S. (2013, January). May-Thurner Syndrome: A Case Report and Review of the Literature. Retrieved May 21, 2016, from http://www.hindawi.com/journals/crivam/2013/740182/
May-Thurner Syndrome. (n.d.). Retrieved May 21, 2016, from https://heart.uvahealth.com/services/compression-disorders/may-thurner-syndrome
Peters, M., Syed, R. K., Katz, M., Moscona, J., Press, C., Nijjar, V., . . . Baldwin, D. (2012, July). May-Thurner syndrome: A not so uncommon cause of a common condition. Retrieved May 19, 2016, from http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3377287/
Weerakkody, Y. (n.d.). May-Thurner syndrome | Radiology Reference Article | Radiopaedia.org. Retrieved May 19, 2016, from http://radiopaedia.org/articles/may-thurner-syndrome-2