RISK-FACTORS FOR DEEP VENOUS THROMBOSIS OF THE UPPER EXTREMITIES

Background: Hypercoagulable states and triggering factors (surgery, tr auma, immobilization, pregnancy, and use of oral contraceptives) are a ssociated with an increased risk for deep venous thrombosis of the low er extremities. In contrast, risk factors for deep venous thrombosis o f the upper extremities have not been identified. Objective: To evalua te the prevalence of hypercoagulable states and triggering factors in patients with primary deep venous thrombosis of the upper extremities. Design: Frequency-matched case-control study. Setting: Hemophilia and thrombosis center at a university hospital. Patients: 36 patients who had primary deep venous thrombosis of the upper extremities, 121 pati ents who had primary deep venous thrombosis of the lower extremities, end 108 healthy controls. Patients who had deep venous thrombosis of t he lower extremities and study controls were frequency-matched by age, sex, geographic origin, and social status with patients who had deep venous thrombosis of the upper extremities. Measurements: Resistance t o activated protein C was evaluated by a clotting method based on the activated partial thromboplastin time. If test results were abnormal o r borderline, DNA analysis for substitution in coagulation factor V ge ne was done. Antithrombin, protein C, protein S, antiphospholipid anti bodies, and total plasma homocysteine levels were also measured. Resul ts: Prevalences of abnormalities of the natural anticoagulant system ( 9 %) and hyperhomocysteinemia (6 %) in patients who had deep venous th rombosis of the upper extremities were similar to prevalences of both factors in controls (6% and 7%, respectively) but lower than in patien ts who had deep venous thrombosis of the lower extremities (31% and 14 %, respectively). Antiphospholipid antibodies were found only in patie nts who had venous thrombosis of the lower extremities (7%). The overa ll prevalence of hypercoagulable states in patients who had thrombosis of the upper extremities (15%) was similar to that in controls (12%) but was significantly lower than that in patients who had thrombosis o f the lower extremities (56%). A recent history of strenuous exercise of muscles in the affected extremity was the most frequent triggering factor for patients who had deep venous thrombosis in the upper extrem ities (33%). Conclusions: This preliminary study indicates that the pr evalence of hypercoagulable states is low in patients who have primary deep venous thrombosis of the upper extremities.