(Stroke. 2005;36:1822.)
© 2005 American Heart Association, Inc.
Letters to the Editor |
Cerebral Venous Sinus Thrombosis: Prevention of Recurrent Thromboembolism
Department of Neurology, Radboud University Nijmegen Medical Centre, The Netherlands
To the Editor:
Patients who have recovered from cerebral venous sinus thrombosis (CVST) are at risk for sustaining a recurrence of CVST or other thrombotic events (Table). For example, in the recent International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT) that was performed in 624 patients with cerebral vein or dural sinus thrombosis, the cumulative risk for recurrent CVST or other thrombotic events after CVST was 6.5%.1 Recurrent thrombosis is potentially fatal. Therefore, an important clinical question is whether recurrence of CVST or other thrombotic events can be prevented in this group.
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Currently, the standard care for patients with a first episode of CVST is anticoagulation therapy, which is usually prescribed for 3 to 6 months in the absence of an identifiable cause.2 However, controlled data about the benefit and optimal duration of oral anticoagulation in patients with CVST are missing.3 More prolonged treatment may be required, because the cumulative risk for recurrent CVST or other thrombotic events after 3 to 6 months of oral anticoagulation therapy ranges between 5.5 and 26% (calculated over a mean follow-up period of 18 to 77.8 months).2,4,5 At the time of these recurrences, which mostly occurred within 1 year, none of the patients received anticoagulation therapy. In the recent ISCVT study, 58.8% of the patients with a recurrence of thrombotic event were not undergoing anticoagulation therapy.1 The significance of these observations is underscored by the fact that recurrence of cerebral venous thrombosis after stopping anticoagulation therapy can occasionally run a fatal course.6
The need for more chronic treatment is further supported by recent observations on the effects of prolonged anticoagulant therapy in patients with idiopathic venous thromboembolism (either pulmonary or deep venous thrombosis).7 This study evaluated the efficacy of long-term, low-intensity warfarin therapy (international normalized ratio, 1.5 to 2.0) in preventing recurrent thrombotic events among patients with idiopathic venous thromboembolism who had completed at least 3 months of therapy with conventional-dose warfarin. Compared with placebo, long-term and low-intensity warfarin afforded a risk reduction for recurrent thromboembolism of 64% over a mean follow-up period of 2.1 years.
The practical implication was that clinical practice should presumably consist of this prolonged, low-intensity anticoagulant regime, at least for patients with a prior event of pulmonary or deep venous thrombosis.7 In this particular study, patients with CVST were not specifically studied. However, it seems justified to extrapolate the findings on pulmonary embolism or deep venous thrombosis to CVST, because the underlying risk factors associated with these conditions are identical.8 Thus, applying this potential risk reduction of 64% to the ISCVT study, long-term anticoagulation therapy could have prevented recurrent thromboembolism in 15 of the 24 patients where recurrence occurred in the absence of anticoagulants. In other words, prolonged anticoagulation in the ISCVT study could have resulted in a cumulative risk for recurrent CVST and other thrombotic events of 4.1%, instead of 6.5%.
We, therefore, suggest that, to reduce recurrence of thrombotic events after CVST, it may be prudent to treat these patients with long-term anticoagulation therapy. Future research should determine the optimal duration and intensity of oral anticoagulation therapy that is necessary to optimally reduce the risk for recurrence of thrombotic events.
References
- Ferro JM, Canhao P, Stam J, Bousser MG, Barinagarrementeria F; ISCVT Investigators. Prognosis of cerebral vein and dural sinus thrombosis: results of the International Study on Cerebral Vein and Dural Sinus Thrombosis (ISCVT). Stroke. 2004; 35: 664–670.
[Abstract/Free Full Text] - Breteau G, Mounier-Vehier F, Godefroy O, Gauvrit JY, Mackowiak-Cordoliani MA, Girot M, Bertheloot D, Henon H, Lucas C, Leclerc X, Fourrier F, Pruvo JP, Leys D. Cerebral venous thrombosis 3-year clinical outcome in 55 consecutive patients. J Neurol. 2003; 250: 29–35.[CrossRef][Medline] [Order article via Infotrieve]
- Masuhr F, Mehraein S, Einhaupl K. Cerebral venous and sinus thrombosis. J Neurol. 2004; 251: 11–23.[CrossRef][Medline] [Order article via Infotrieve]
- Preter M, Tzourio C, Ameri A, Bousser MG. Long-term prognosis in cerebral venous thrombosis. Follow-up of 77 patients. Stroke. 1996; 27: 243–246.
[Abstract/Free Full Text] - Ferro JM, Lopes MG, Rosas MJ, Ferro MA, Fontes J. Long-term prognosis of cerebral vein and dural sinus thrombosis. Results of the VENOPORT study. Cerebrovasc Dis. 2002; 13: 272–278.[CrossRef][Medline] [Order article via Infotrieve]
- van den Berg JS, Boerman RH, vd Stolpe A, Kremer HP. Cerebral venous thrombosis: recurrence with fatal course. J Neurol. 1999; 246: 144–146.[Medline] [Order article via Infotrieve]
- Ridker PM, Goldhaber SZ, Danielson E, Rosenberg Y, Eby CS, Deitcher SR, Cushman M, Moll S, Kessler CM, Elliott CG, Paulson R, Wong T, Bauer KA, Schwartz BA, Miletich JP, Bounameaux H, Glynn RJ; PREVENT Investigators. Long-term, low-intensity warfarin therapy for the prevention of recurrent venous thromboembolism. N Engl J Med. 2003; 348: 1425–1434.
[Abstract/Free Full Text] - de Bruijn. Cerebral Versus Sinus Thrombosis. Clinical and Epidemiological Studies. Amsterdam: Thesis Publishers; 1998.
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