Case Presentation: A 36-year-old female with past medical history of endometrial polyp and lumbar degenerative disease presented with chest pressure, lower extremity swelling, and shortness of breath for four days. Physical examination revealed increased work of breathing, bilateral crackles, and trace lower extremity edema. Lab work showed elevated NT-Pro-BNP of 5930 pg/ml, mildly elevated creatinine, normal liver function test, normal thyroid function test, and elevated ESR/CRP inflammatory markers. Deep venous thrombosis (DVT) was ruled out by lower extremity venous doppler. CT chest, abdomen, and pelvis revealed bilateral pleural effusions, pulmonary edema, borderline cardiomegaly, hepatosplenomegaly, prominent parametrial veins and enlarged left ovarian vein consistent with pelvic congestion. A working diagnosis of new onset congestive heart failure exacerbation was suspected, and patient was treated with intravenous furosemide with improvement in symptoms. Transthoracic echocardiogram showed preserved left ventricular ejection fraction, no diastolic dysfunction, and no valvular abnormality. A CT venogram of the abdomen and pelvis showed left common iliac vein compression by the overlying right common iliac artery. Cardiac MRI was negative for infiltrative pathology. Given lower extremity edema, pelvic congestion, and imaging finding, patient was diagnosed with May-Thurner syndrome. Intravascular ultrasound was performed by intervention cardiology and findings were consistent with May-Thurner syndrome. She underwent successful percutaneous stent placement of inferior vena cava, left common iliac, and left external iliac vein with significant improvement in stenosis.
Discussion: May-Thurner syndrome (MTS), also known as iliac vein compression syndrome, is an underdiagnosed pathology due to the overriding right common iliac artery causing compression of the left common iliac vein against the lumbar spine. MTS mostly occurs in the second to fourth decade of life. MTS is often asymptomatic in the early stage. As such, initial symptomatic presentation can include pelvic congestion, unilateral left lower extremity swelling, and/or unilateral DVT. In our case, the patient presented with signs of new onset acute congestive heart failure with work up revealing MTS. If MTS is suspected, contrast venography, magnetic resonance imaging, or intravascular ultrasound should be performed. The mainstay of therapy has traditionally involved open repair of the affected vein. However, the standard of care has since evolved into a hybrid approach, involving the combination of thrombolytics and endovascular intervention. Excellent short-term results with stent placement have been reported. When left untreated, MTS leads to long-term disabling complications including chronic leg swelling, venous stasis ulcers, DVT, and pulmonary embolism.
Conclusions: MTS should be considered in the different diagnosis of patient presenting with unexplained lower extremity edema and pelvic congestion, especially in young women. As MTS is underdiagnosed, there should be a low threshold for inpatient investigation especially if other etiologies are ruled out. Failure to recognize MTS early can lead to future DVT. Therefore, mechanical compression should be ideally recognized prior to the onset of DVT. Endovascular treatment with stent placement is a good alternative to surgical repair and yields excellent short-term results.