Iliac Vein Compression Syndrome

Authors:
Corey Goldman, MD, PhD; Back Kim, MD; and Tae An Choi, ANP-BC
Heart Vein NYC, New York, New York

Citation:
Goldman C, Kim B, Choi TA. Iliac vein compression syndrome. Consultant. 2017;56(12):722-724.

A 38-year-old para 1 woman presented with a 7-year history of painful swelling and associated mild hyperpigmentation of the lower extremities. The swelling initially had been treated conservatively with compression stockings, but because her symptoms had continued, she underwent endovenous laser treatment (EVLT) and calf phlebectomy, which had resulted in marginal improvement.

History. During her recent pregnancy, the woman had experienced marked worsening of the swelling in her left thigh and leg. No deep-vein thrombosis (DVT) had been identified, and despite negative findings on lower-extremity venous duplex ultrasonography, she was treated empirically with subcutaneous enoxaparin for possible missed iliofemoral DVT. Anticoagulation had failed to improve symptoms. She had experienced mild improvement postpartum, but the limb heaviness and throbbing had persisted, especially when she walked up stairs.

Physical examination. Physical examination demonstrated mild thigh and calf asymmetry associated with skin hyperpigmentation, 1+ edema, and a bulging serpiginous great saphenous vein (GSV) branch coursing from the lateral inguinal region to the distal medial thigh (Figure 1).

Diagnostic tests. A repeated superficial venous reflux study with duplex ultrasonography demonstrated recurrent reflux of the left GSV. The decision to proceed with venography was agreed upon.

Left iliac venography was performed using proximal GSV venipuncture. An intravascular ultrasound (IVUS) catheter was advanced under fluoroscopy, the results of which demonstrated a 65% diameter reduction of the common iliac vein compared with an adjacent normal segment (Figure 2). Limited venography using 20 mL of iso-osmolar contrast confirmed the focal stenosis (Figure 3).

Figure 2: IVUS-guided stenting was performed under fluoroscopy without contrast. Before left iliac vein stenting (left), the IVUS catheter nearly occluded the lumen. After left iliac vein stenting, a lumen is more apparent.

Figure 3: Fluoroscopy of the pelvis using contrast-filled expansion balloons before (left) and after (right) stent deployment revealed 65% stenosis of the left common iliac vein.

Discussion. This patient has classic iliac vein compression syndrome, also known as May-Thurner syndrome.^1,2

In iliac vein compression syndrome, the overlying right iliac artery causes extrinsic compression of the left iliac vein in more than 80% of cases, resulting in impaired limb venous return.³ The cardinal features of the syndrome are asymmetric limb swelling and associated aching and heaviness. Symptom severity varies from asymptomatic to severe chronic venous insufficiency (CVI) with DVT.⁴ Clinically, similar unilateral findings on the right are due to right-sided iliac vein compression from the ipsilateral iliac and femoral arteries.^5,6

The clinical pathway for a patient such as ours is parallel to the initial conservative management of CVI after confirming the presence of superficial venous reflux and the absence of DVT using venous duplex ultrasonography. Standard management includes leg elevation and compression. Because conservative management failed to produce adequate relief in our patient’s case, treatment included closure of the incompetent superficial veins using EVLT and phlebectomy. Despite this standard approach, her bothersome symptoms of ipsilateral edema and tenderness persisted. While the presence of intractable lymphedema was considered, the fluctuating nature of the edema was more suggestive of a reversible process. Iliac venography using IVUS was chosen to assess the iliac vein because it allows immediate treatment with stenting when obstruction is present, and it more clearly identifies the degree of iliac vein compression compared with computed tomography (CT), magnetic resonance imaging, and routine venography.

The normal iliac arteries traverse the corresponding iliac veins. Anatomically, iliac vein compression has been observed in as many as 24% of asymptomatic patients and may be dismissed as a normal variant.^7,8 In this context, routine abdominal and pelvic CT scan reports may overlook the finding of iliac vein narrowing. More recently, our clinic and others⁹ use IVUS to better quantify the degree of compression. While pregnancy may have exacerbated our patient’s symptoms, the causative clinical correlates leading to compression have not yet been defined. Despite this, symptomatic iliac vein compression syndrome is a well-defined clinical constellation that includes clinical signs and symptoms and radiologic findings.

Conservative treatment using compression stockings is the first-line therapy but rarely reverses symptoms in the long term. Stenting of the compressed vein often results in rapid resolution of pain, burning, and heaviness.

After stenting, the vein wall is potentially thrombogenic due to pressure injury from the deployment balloon and from the metallic stent. Maintenance of stent patency requires either antiplatelet or anticoagulant medications. While the approach to anticoagulation with arterial stents is guidelines-based, the optimal antithrombotic regimen has not yet been delineated. In our experience, dual antiplatelet therapy is insufficient in the immediate post-stenting period (1 month) and is associated with an increased occurrence of subacute stent thrombosis. In this context, we employ therapeutic anticoagulation for 1 to 3 months using one of the novel anticoagulants (rivaroxaban or apixaban) and switch to a single antiplatelet regimen thereafter indefinitely. Other authors have stated that anticoagulation is guided by the presence or absence of intraluminal thrombus.¹⁰

Outcome of the case. Vein stenting resulted in rapid and significant improvement in limb pain, and these results have continued for more than 1 year. Her acute inflammation-associated skin changes rapidly subsided, including a decrease in tenderness and resolution of erythema and warmth. The patient further noted less skin dryness and lightening of the initial mild hyperpigmentation. 

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