Summary
One hundred and three patients suffering from recurrent venous thrombosis, recurrent
arterial thromboembolism and/or recurrent myocardial infarction and 50 healthy subjects
were tested for Hageman factor (FXII) coagulant activity and antigen. Among the 103
patients we identified 15 subjects with FXII deficiency (15%), 3 with protein C deficiency
(3%) and 3 with protein S deficiency (3%). Combined FXII and protein C, protein S
or antithrombin III deficiency was not observed. The 103 patients were devided into
subgroups according to the type of thrombotic complication. Among patients with exclusively
recurrent venous thromboembolism 8% (p = 0.153) were deficient in FXII. Among patients suffering from recurrent arterial
thromboembolism and/or myocardial infarction, the incidence of FXII deficiency was
significantly higher (20%, p < 0.003). In 67% of the patients with FXII deficiency a positive family history of
thrombosis could be established. In contrast, only 32% of all venous and 28% of all
arterial thrombosis patients had a positive family history. We believe that reduced
levels of FXII should be considered as a risk factor in the development of thromboembolism.
Consequently, more attention should be payed to the measurement of FXII when evaluating
thromboembolic risk factors especially in cases of recurrent arterial thromboembolism
and/or myocardial infarction.
