Discussion
Benign Superior vena cava syndrome accounts for less than 10% .Half of them due to fibrosing mediastinitis and use of indwelling catheters which increase incidence of thrombosis .
Antiphospholilpid syndrome is a thrombophilic syndrome in which venous or arterial thrombosis or both,may occur in patient with antiphospholipid antibodies positive ,the diagnosis of definite antiphospholipid syndrome must include at least one clinical event of arterial or venous thrombosis and at least one of the laboratory criteria [lupus anticoagulant or anticardiolipin IgG or IgM antibodies,this was reported in three case at Iran Journal of Immunology(3), Spain (4)and Israel(5).
The presence of a thrombus should be considered in patients with acute onset of symptoms, occlusions that can easily be traversed by a wire, and when SVCS are secondary to central venous catheters. In these patients, a trial of systemic anticoagulation or, in the acute setting, thrombolysis can be attempted by using thrombolytic agents delivered at the site of the clot through a catheter, which allows more effective local action. Reports of systematic administration of thrombolytic agents have also been described (6).By reducing the thrombus load, the length of the obstruction can often be reduced, thus reducing the number of stents needed. (7) However, thrombolysis is most effective if it is started within 2-5 days of onset of symptoms and tends to be ineffective if started after 10 days(8).
Gray et al (9)found that 88% of the cases had a successful outcome when thrombolytic treatment was commenced within 5 days. The success rate dropped to 25% when it was started after 5 days(9).They also observed that catheter-related SVCS demonstrated a better response to thrombolysis, which was attributed to the earlier detection of symptoms secondary to catheter dysfunction, the absence of extrinsic compression, and the ability to infuse the thrombolytic agent directly to the site of the thrombus via the existing catheter(11). Caution should be exercised in patients with cystic fibrosis because an increased risk of hemoptysis and gastrointestinal bleeding has been reported in this patient population(6).
Newer techniques that use pharmacomechanical thrombolysis tools, such as the Trellis Thrombectomy System (Bacchus Vascular, Santa Clara, CA) and Trellis infusion system (Covidien, Santa Clara, CA), have shown promising results in reducing the thrombus load(10,11).