Figure 1. Abdominal-pelvic coronary computed tomography angiography showing the i...

Figure 2. Cavo-iliac phlebography showing the occlusion of the left common iliac vein.

Figure 3. Zilver Vena self-expandable stent implantation.

Figure 4. Final angiographic result.

Introduction

May-Thurner syndrome is a rare clinical entity in which the left common iliac vein is compressed by the right common iliac artery at L5 vertebra level.¹ This sustained compression and trauma caused by the pulsatile energy of the artery on the vein damages the intima occluding venous flow andprompting the development of venous thrombosis.^2,3

Clinical case

This is the case of a 62 year-old-woman with a cardiovascular risk factor (former smoker). No other relevant past medical history was reported.

She presents with pain and swellingof left lower extremity of 12-month duration.

On the physical examination, the patient shows redness and increased temperature of her left lower extremity with hypersensitivity to compression associated with the presence of edema 3/6.

The venous echo-Doppler of the left lower extremity performed showed signs of deep venous thrombosis and varicose veins at pelvic level draining into both femoral saphenous veins with venous dilatation at such level.

The abdominal-pelvic coronary computed tomography angiography performed reveals a severe obstruction of the left iliac vein by the right common iliac artery at 5L vertebral level (May-Thurner syndrome) with pelvic varicose veins with hypogastric collateral circulation (figure 1).

Since the coronary computed tomography angiography suggests a diagnosis of May-Thurner syndrome and the patient shows signs of pain and edema in her left lower extremity, it was decided to perform endovascular treatment on the left common iliac vein.

Initially, the left femoral venous access was used to enter a 4-Fr introducer sheathand perform a diagnostic cavo-iliac phlebography that confirms the total occlusion of the left common iliac vein, unlike the left coronary computed tomography angiography that showed a severe obstruction of the left common iliac artery had due to the extrinsic compression of the right common iliac artery (figure 2).

It was decided to attempt the recanalization of the left iliac vein via endovascular access. First, the 4-Fr introducer sheath was changed for a 7-Fr sheath. After several attempts a 0.035 in hydrophilic guidewire (TERUMO) successfully crosses the total occlusion and advances towards the inferior vena cava. Afterwards, a 7- Fr JR guide catheter was used. Several thrombus aspirations were tried directly from it, but no macroscopic thrombotic material was retrieved. Since no thrombus was seen on the angiography, it was decided to continue with the procedure. Afterwards, the TERUMO guidewire was changed for a 0.035 in guidewire to provide extra support (SUPRACORE) and a Zilver Vena self-expandable stent was implanted (figure 3). An 8.0 mm-diameter balloon was used for post dilatation. The control angiography revealed the presence of another severe, radiolucent obstruction in the left external iliac vein and a Protégé GPS self-expandable stent was implanted. An 8.0 mm-diameter balloon was used for postdilatation with very good final angiographic results (figure 4). 

The patient progression was good, and she was discharged 24 hours later on a 6-month course of oral anticoagulant therapy.

At the 3-month follow-up the examination performed by the patient’s general physician confirmed that both the signs and symptoms of the disease had improved.

Discussion

The compression of the left common vein by the right common iliac artery—May-Thurner syndrome—is an entity that, on many occasions, is the underlying cause for deep venous thrombosis. Its actual prevalence is still unknown, but it is more common in women between the ages of 20 and 40. We should mention here that this condition often goes misdiagnosed.

The diagnosis of this entity is usually achieved by looking at the symptoms and clinical findings seen during the physical examination. These findings are complemented by the results obtained from the ultrasonography,^4,5 coronary computed tomography angiography, and magnetic resonance imaging performed. These imaging modalities contribute to achieve diagnosisand plan treatment. However, the cavo-iliac phlebography is crucial for diagnostic confirmation purposes. It also looks for the presence of chronic lesions inside the vessel and congenital anomalies often associated with this syndrome like duplicated venous system or rudimentary venous system.⁶

Currently, both the endovascular treatment and medical therapy have proven effective with good long-term results. In our case, we saw progression of the disease after confirmation of the total occlusion of the left common iliac vein on the cavo-iliac phlebography 2 months after performing the abdominal-pelvic coronary computed tomography angiography. Therefore, it was decided to perform the endovascular recanalization of the vessel and implant 2 self-expandable stents with very good angiographic results. Afterwards, the patient was discharged on oral anticoagulation. We could argue if, after phlebographic confirmation of the left common iliac veintotal occlusion, the procedure should have continued considering the eventual risk of thrombi embolization after crossing the guidewire during stent implantation. However, since no macroscopic thrombotic material was retrieved after multiple aspirations performed directly with the 7- Fr JR guide catheter and no thrombus was seen on the angiographic imaging, it was decided to continue the procedure achieving the successful recanalization of the vessel. The patient was discharged 24 hours later on a 6-month course of anticoagulation therapy.

Currently, endovascular treatment is the gold standard for the management of the May-Thurner syndrome and it gives good long-term results and a low rate of complications. The patient needs to be on sustained anticoagulation therapy for, at least, 6 months. According to medical literature, a 6-to-12-month course of anticoagulation therapy is advisable with only 1 episode of associated deep venous thrombosis reported. Also, it is advisable to anticoagulate indefinitely in the presence of multiple episodes of associated thrombosis.⁷

Conclusion

The May-Thurner syndrome is a progressive disease that can trigger serious complications in the long term such as deep venous thrombosis, post-thrombotic syndrome, and pulmonary thromboembolism. Therefore, an early diagnosis and treatment is crucial in the management of this entity.

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