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).