Serpiginous Pubic Vein: A Clue for May-Thurner Syndrome
By: Ritoban Sen, MD, John Blebea, MD, MBA, & Harry Ma, MD, PhD
Department of Surgery
University of Oklahoma College of Medicine
May-Thurner syndrome is an under-reported cause of a common clinical condition. Although it has an anatomic prevalence of approximately 22%, it is only reported as a potential cause in 2-3% of lower extremity DVTs. It is likely overlooked even in cases of recurrent DVTs with no other identifiable inciting events. We report a case of a patient with May-Thurner syndrome who presented not only with recurrent lower extremity DVTs, but also a prominent subcutaneous collateral vein in the pelvic region which prompted further investigation and led to the identification of the underlying condition.
May-Thurner syndrome is a clinical condition in which patients develop ilio-femoral deep vein thrombosis (DVT) due to the anatomic compression of the left common iliac vein between the crossing right common iliac artery and underlying lumbar spine. It was first described in 1956 by Robert May and Josef Thurner of Austria in a paper entitled ‘The Cause of the Predominantly Sinistral Occurrence of Thrombosis of the Pelvic Veins’ in which they describe the area as a ‘spur’ which they found to occur in 22% of the 430 cadavers they examined. Subsequent retrospective analysis of CT scans reported a similar prevalence of 22-24%. However, in clinical practice, it is described as an identifiable cause in only 2-3% of all lower extremity DVTs. This is thought to reflect both a lack of causative recognition and subsequent underreporting in the literature. More recently, the definition of May-Thurner syndrome has been expanded to a broader disease profile known as non-thrombotic iliac vein lesions (NIVL) which can involve both the right and left iliac veins as well as multiple other named venous segments. This syndrome frequently manifests as pain when the limb is dependent and/or significant swelling of the whole limb.
A 78 year old Caucasian woman presented with a history of four episodes of left lower extremity DVTs in her life-time as well as persistent swelling of the leg. The patient stated that the first episode had been precipitated by prolonged bed rest after a hysterectomy but she could not recall any specific inciting events which may have led to the other episodes. She had been on therapeutic warfarin for several years but still developed DVTs despite this.
Physical examination was unremarkable except for mild swelling of the left lower extremity and the presence of a tortuous vein in the subcutaneous tissue of the suprapubic area (Fig 1). A CT scan demonstrated the compression of the left common iliac vein by the overlying right common iliac artery (Fig 2) as well as a large venous collateral arising from the left iliac vein and draining into the right iliac system (Fig 3).
After appropriate pre-operative preparation, a venogram was performed. In the supine position, vascular access was obtained under ultrasound guidance via the left common femoral vein and a 5 French sheath was placed. The venogram revealed a chronic occlusion of the left common iliac vein as well as mild disease in the distal external iliac vein and the proximal common femoral vein (Fig 4). The cross-pelvic collateral vein and other draining vessels were clearly evident. The inferior vena cava was widely patent. Although it was initially challenging, a 0.035 angled Glidewire (Terumo Interventional Systems; Somerset, NJ) supported by a 5 Fr Berenstein catheter (Angiodynamics; Latham, NY) was navigated across the lesion (Fig 5). We then performed balloon venoplasty of the left common iliac vein and IVC junction with a 20x40 mm Atlas high-pressure balloon (Bard Peripheral Vascular; Tempe, AZ) and venoplasty of the external iliac vein with a 12x40mm Charger balloon (Boston Scientific; Marlborough, MA). This was followed by the placement of a series of Wallstents, 20x40mm, 18x40mm and16x40mm (Boston Scientific; Marlborough, MA) extending from the inferior vena cava to the external iliac vein. A completion venogram demonstrated rapid flow through the iliac system and complete resolution of cross-pelvic collateral flow (Fig 6). The patient did well post-operatively and her left leg swelling receded.
Clinical May-Thurner syndrome has historically not been frequently diagnosed but should be considered in the differential diagnosis in patients who present with recurrent lower extremity DVTs. The reason for the infrequent diagnosis and reporting of May-Thurner syndrome may be the prevalence of other more easily recognized risk factors for DVT in these patients. The left-sided predominance for DVT (56%) also suggests this anatomic risk factor to be more important that previously appreciated. Patients presenting with dilated subcutaneous veins in the vulvar/perineal locations should prompt the clinician to consider proximal venous stenosis/occlusion. Venography is both diagnostic and provides the opportunity for therapeutic interventions which most commonly include stenting of the compressed common iliac vein.
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