Effectiveness of long term oral anticoagulation treatment in preventing venous thrombosis in hereditary protein S deficiency.

In eight of 14 patients who were deficient in protein S and who belonged to two unrelated families thrombosis presented as thrombophlebitis in seven and deep vein thrombosis in six, complicated by pulmonary embolism in four and leg ulcers in two. In four patients superficial thrombophlebitis preceded deep vein thrombosis by one to 11 years. Post-thrombotic varicose veins and venous insufficiency had developed in four patients. In three of those and in a fourth patient symptomatic superficial thrombophlebitis, deep vein thrombosis, and pulmonary embolism did not recur while they were taking oral anticoagulant treatment for six to 12 years. The anticoagulation intensity corresponded to international normalised ratio values of over 2.5. It is concluded that the benefits of anticoagulant treatment for patients with congenital thrombotic disease are great, and thus it is necessary to make an early diagnosis and treat patients at risk of developing thrombosis.