May-Thurner Syndrome, also known as iliac vein compression syndrome, was first described anatomically by May and Thurner in 1956 as a spur-like formation of the left common iliac vein in 22% of autopsies1. They believed this was formed as a result of the chronic pulsations of the overriding right iliac artery, leading to chronic trauma of the common iliac vein wall therefore causing local intimal proliferation, reduced venous return and chronic venous obstruction2. They concluded these changes were the factors causing a left-sided deep venous thrombus (DVT) formation.
May-Thurner Syndrome is defined as a >50% luminal constriction of the left common iliac vein, with an incidence of 18%–49% 3 and a female:male incidence of 3:1. It occurs most commonly in the second to fourth decades of life usually presenting with left lower limb swelling, pain, varicosities, venous stasis changes or DVT4 and is the concluding diagnosis in 2-5% of patients with a left lower limb DVT5.
Surgical approaches and endovascular interventions have been effective in the acute phase of the disease and endovascular venous stents can resolve the manifestations of chronic venous compression. In the acute phase, catheter-directed thrombolysis is accepted as the most appropriate treatment, which can be complemented by the use of a device to disrupt the venous clot, such as the Angiojet. Long-term, anticoagulation alone is ineffective and a consensus regarding the usage and duration of antiplatelet and antithrombotic therapy has not been established5.
Angiojet is proprietary product that pharmacomechanically removes clot6. It involves a catheter over the wire technique where a wire is place over the length of the occluded vessel. The catheter is threaded over the wire and can deliver pressurised saline or thrombolytics to disrupt the clot. After an appropriate dwell time the clot is the aspirated via the catheter. To prevent embolisation a caval filter can be deployed prior to the procedure though the risk of pulmonary embolism appears to be low7. Given the mechanical aspect of the device there is an element of haemolysis which can manifest with arrhythmia, blood pressure changes and commonly haematuria due to haemaglobinuria. Patients are anti-coagulated during the procedure and post procedure, though duration of anticoagulation will likely be modified due to clot burden and predisposing factors. There is a paucity of evidence to guide the use of these techniques and as to the relative benefits. Those most likely to benefit are those with iliofemoral DVT, symptoms for less than 14 days, low risk of bleeding and good functional status8. There is some evidence for decreased post thrombotic syndrome symptoms but none that shows lower mortality or rates of PE9.