Hyperhomocysteinemia Is a Risk Factor of Recurrent Venous Thromboembolism
S. Eichinger (1) , A. Stümpflen (2) , M. Hirschl (3) , C. Bialonczyk (4) , K. Herkner (5) , M. Stain (1) , B. Schneider (6) , I. Pabinger (1) , K. Lechner (1) , P. A. Kyrle (1)
From the (1) Department of Internal Medicine I, University of Vienna, (2) Department of Internal Medicine II, University of Vienna, (3) Hanuschkrankenhaus, Vienna, (4) Wilhelminenspital, Vienna, (5) Department of Pediatrics, University of Vienna, and th
Hyperhomocysteinemia is a risk factor of venous thromboembolism.
The risk of recurrence in patients with hyperhomocysteinemia is
unknown, and the optimal therapy for these patients after acute venous
thromboembolism is uncertain.
In a multicenter study, 264 patients with an objectively documented
single episode of idiopathic venous thromboembolism were prospectively
followed after discontinuation of oral anticoagulants. Patients
were classified as hyperhomocysteinemic if their homocysteine levels
exceeded the 95th percentile of the controls. The outcome events
studied were objectively confirmed deep-vein thrombosis and/or
Homocysteine levels were elevated in 66 patients (25%) and normal
in 198 patients (75%). Recurrent venous thromboembolism occurred in
12 of 66 patients with hyperhomocysteinemia (18.2%) and in 16 of
198 patients without hyperhomocysteinemia (8.1%). The cumulative
probability of recurrence 24 months after discontinuation of oral anti-coagulants
was 19.2 percent (95 percent confidence interval 8.7-27) in
patients with hyperhomocysteinemia and was 6.3 percent (95 percent
confidence interval 2.4-10.1; p = 0.001) in those without hyperhomocysteinemia.
The relative risk of recurrent thrombosis was higher in
patients with hyperhomocysteinemia [RR 2.7 (1.3-5.8), p = 0.009].
Patients with hyperhomocysteinemia are at high risk of recurrent
venous thromboembolism. The high prevalence of hyperhomocysteinemia
in thrombosis patients together with the increased risk of
recurrence warrants extended patient screening. The impact on the risk
of recurrence of prolonged anticoagulation, supplementation of folate
and vitamin B12 , or both have to be investigated.