May-Thurner syndrome

May-Thurner syndrome
Classification and external resources
Iliac veins
ICD-10	I80.2
DiseasesDB	33411

In medicine, May-Thurner syndrome is a rare condition in which blood clots, called deep venous thrombosis (DVT), occur in the iliofemoral vein due to compression of the common venous outflow tract of the left lower extremity. The specific problem is compression of the left common iliac vein by the overlying right common iliac artery.^[1][2] This leads to pooling or stasis of blood, predisposing the individual to the formation of blood clots. May-Thurner syndrome is therefore more common in the left leg as the artery acutely overlaps the Left Iliac Vein. A broader disease profile known as nonthrombotic iliac vein lesions (NIVL) can involve both the right and left iliac veins as well as multiple other named venous segments.

Epidemiology and Diagnosis

It causes between two and five percent of lower-extremity venous disorders. May-Thurner Syndrome is often unrecognized; however current estimates are that this condition is three times more common in women than in men. It typically presents in the second to fourth decades of life.

It is important to consider May-Thurner Syndrome in patients who have no other obvious reason for hypercoagulability and who present with left lower extremity thrombosis. To rule out other causes for hypercoagulable state check the patient's: Antithrombin, Protein C, Protein S, Factor V Leiden, and Prothrombin G20210A.

Venography will demonstrate the classical syndrome.

In the broader disease profile the nonthrombotic iliac vein lesions (NIVLs) in the symptomatic ambulatory patient are usually not seen by venography. Morphologically, intravascular ultrasound (IVUS) has emerged as the best current tool in the broader sense. Functional testing such as duplex ultrasound, venous and interstitial pressure measurement and plethysmography are utilized routinely.

Mechanism

In contrast to the right common iliac vein, which ascends almost vertically to the inferior vena cava, the left common iliac vein takes a more transverse course. Along this course, it underlies the right common iliac artery, which may compress it against the lumbar spine.

In addition to compression the vein develops fibrous spurs from the effects of the chronic pulsatile compressive force from the artery. the Narrowed turbulent channel predisposes the patient to thrombosis.

This compressed, narrowed channel causes stasis of the blood, which is one element of Virchow's triad that precipitates deep vein thrombosis.

Treatment

Management of the underlying defect is imperative to preventing further attacks. If the patient has extensive thrombosis, it may be prudent to consider pharmacologic and/or mechanical (also known as pharmacomechanical) thrombectomy to decrease the incidence of post-thrombotic syndrome. At the time of the thrombectomy the use of an inferior vena cava filter may be considered to prevent pulmonary embolism in these patients although filter use continues to evolve and will not correct the underlying lesion alone. Patients with May-Thurner syndrome may require an angioplasty of the iliac vein. Generally a braided stainless steel stent is used to support the area from further compression following angioplasty.

References

1. ^ May R, Thurner J (1957). "The cause of the predominantly sinistral occurrence of thrombosis of the pelvic veins". Angiology 8 (5): 419–27. doi:10.1177/000331975700800505. PMID 13478912. 
2. ^ Fazel R, Froehlich JB, Williams DM, Saint S, Nallamothu BK (2007). "Clinical problem-solving. A sinister development--a 35-year-old woman presented to the emergency department with a 2-day history of progressive swelling and pain in her left leg, without antecedent trauma". N. Engl. J. Med. 357 (1): 53–9. doi:10.1056/NEJMcps061337. PMID 17611208. 

External links

• synd/3472 at Who Named It?
• Vascular medicine - Vascular medicine and angiology related topics for experts and laypersons.

See also

• Chronic cerebrospinal venous insufficiency - Venous compression in the neck
• Thoracic outlet syndrome - Similar compression in the shoulders.
• Budd–Chiari syndrome - Venous compression or obstruction in the liver.