Purpose: To assess the incidence of congenital and acquired thrombophilia and to analyse the clinical characteristics of a group of patients with high risk criteria for thrombophilia.
Patients and methods: Two hundred and eighty-five consecutive patients seen at the anticoagulant outpatient clinic of the Oviedo Central Hospital between 1987 and 1993 were evaluated. The patients had to meet one or more of the following: 1) venous thrombosis (VT) under 45 years of age; 2) repeat VT; 3) family history of VT; 4) unusual VT location (mesenteric, brain, etc.). The study was performed 4 to 7 months after the first acute episode and at least one month after suppression of anti-vitamin K treatment. The following test were carried out: blood cell counts, basic coagulation tests (APTT, PT, TT, RT and fibrinogen), lupus-like anticoagulant detection, with and without platelet extract, diluted tissular thromboplastin inhibition test, antibodies, anticardiolipin, liver and kidney functional screen, cholesterol, HDL, triglycerides and glycaemia. The venous occlusion test after 20-minute stasis was used for the global fibrinolysis study. The statistical evaluation was performed with the SPSS programme.
Results: Biologic alterations were present in 98 patients (35%), 12% corresponding to congenital thrombophilia and 23% to acquired thrombophilia. The study was normal in 187 patients (65%). Of the patients with congenital thrombophilia, 4.9% had protein C (PC) deficit, 3.4% protein S (PS) deficit, and 2.4% antithrombin III (AT-III) deficit. Of the patients with acquired thrombophilia, 4.5% had antiphospholipid antibodies and 18% had impaired fibrinolysis. Of all the data analysed, the patient history was found of scarce predictive value as to the risk for thrombophilia. Significant differences were found for family history of VT (p < 0.0005) and for the association of more than one criteria for inclusion (p < 0.001).
Conclusions: No conclusions could be drawn from this study regarding the prophylactic attitude in patients with congenital abnormalities or anti-phospholipid antibodies. It is recommended to assess in such patients PC, PS and AT-III activities.