Aorta
IVC
RCIA
LCIA
LCIV
Figure 2. Image of the left common iliac vein thrombus captured during thrombectomy. The aorta and the common iliac arteries have been drawn for clarification. The blue arrow is pointing at the thrombus. IVC= Inferior Vena Cava, RCIA= Right Common Iliac Artery, LCIA= Left Common Iliac Artery, LCIV= Left Common Iliac Vein
DISCUSSION May Thurner Syndrome is defined as extrinsic venous compression by the arterial system against bony structures in the iliocaval venous territory, most commonly of the left common iliac vein by the right common iliac artery. 3 It develops in individuals with an anatomic variant in which the right common iliac artery overlies and compresses the left common iliac vein against the lumbar spine. 2 Clinical phases of MTS include a prolonged asymptomatic period of left iliac vein compression followed by the gradual development of an intraluminal venous fibrous band (ie, spur), which can subsequently progress to an acute unilateral left iliofemoral DVT. 5 Prevalence of MTS is unknown for certain and is likely underestimated, largely because most individuals with this anatomic anomaly remain asymptomatic. 3 Among symptomatic patients, MTS has been estimated to be the underlying etiology in 2 to 5 percent of patients. 3 A greater than 70% compression of the iliac vein is needed to cause DVT in MTS. 4 MTS is more common in females than in males and occurs most frequently between the second and fourth decades of life.4 Research suggests that a female’s pelvis exhibits more of an accentuation of the lumbar lordosis that pushes the lower lumbar vertebrae anteriorly, thereby compressing the left common iliac vein against the right common iliac artery. 5 Duplex ultrasound is used initially for diagnostic purposes for patients with MTS with thrombosis. 1 For MTS without thrombosis, noninvasive venous imaging such as CT or MR venography should be used for diagnosis and intervention of the deep leg veins. 1 Treatment recommendations differ between thrombotic and nonthrombotic MTS. 3 For nonthrombotic MTS with no or mild symptoms, treatment is conservative such as compression stockings. 1 For nonthrombotic MTS with moderate to severe symptoms, treatment is angioplasty and stenting of affected segment. 3 For thrombotic MTS with no contraindications to lytic therapy, such as in this case, treatment begins with full therapeutic anticoagulation. 3 Figure 2. Image of the left common iliac vein thrombus captured during thrombectomy. The aorta and the common iliac arteries have been drawn for clarification. The blue arrow is pointing at the thrombus. IVC= Inferior Vena Cava, RCIA= Right Common Iliac Artery, LCIA= Left Common Iliac Artery, LCIV= Left Common Iliac Vein The patient had elevated D-dimer levels and factor VIII activity assay. She was started on enoxaparin 30 mg subcutaneously every 12 hours. She underwent a balloon thrombectomy ( Figure 2 ) with stent placement and had subsequent resolution of swelling in the affected leg. The patient was discharged with plans to continue life long Apixaban 5 mg BID to prevent future recurrence. Discussion May Thurner Syndrome is defined as extrinsic venous compression by the arterial system against bony structures in the iliocaval venous territory, most commonly of the left common iliac vein by the right common iliac artery. 3 It develops in individuals with an anatomic variant in which the right common iliac artery overlies and compresses the left common iliac vein against the lumbar spine. 2 Clinical phases of MTS include a prolonged asymptomatic period of left iliac vein compression
Medical treatment with anticoagulation alone is associated with suboptimal outcomes in those with MTS. With successful treatment of MTS, rates of post-thrombotic syndrome are less than 10 percent. 3 Without treatment, post-thrombotic syndrome is associated to occur in 80 to 90 percent of patients. 3 In conclusion, May-Thurner Syndrome is an uncommon and undiagnosed cause of DVT resulting from Iliac vein compression. Clinical symptoms and physical signs do not always correlate with imaging results. Endovascular therapy, a minimally invasive approach to treating venous lesions, is an effective treatment option for this condition, followed by long term anticoagulation. REFERENCES 1. Mangla A, Hamad H. May-Thurner Syndrome. [Updated 2022 May 14]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www. ncbi.nlm.nih.gov/books/NBK554377/ 2. Sharafi S, Farsad K. Variant May-Thurner syndrome: Compression of the left common iliac vein by the ipsilateral internal iliac artery. Radiol Case Rep. 2018;13(2):419-423. doi:10.1016/j.radcr.2018.01.001
3. Mousa AY, AbuRahma AF. May-Thurner syndrome: update and review. Ann Vasc Surg. 2013;27:984–95.
4. Baloch ZQ, Hussain M, Ayyaz M, Dagli N, Abbas SA. May- Thurner Syndrome Presenting as Acute Unexplained Deep Venous Thrombosis. Ann Vasc Surg. 2018 Nov;53:266.e1-266. e3. doi: 10.1016/j.avsg.2018.03.031. Epub 2018 May 21. PMID: 29793013 5. Harbin, MM, Lutsey, PL. May-Thurner syndrome: History of understanding and need for defining population prevalence. J Thromb Haemost. 2020; 18: 534– 542. https://doi.org/10.1111/ jth.14707 ■
27
J LA MED SOC | VOL 174 | FALL 2022
Made with FlippingBook Digital Publishing Software