THE EFFECT OF ASPIRIN ON HEMOSTATIC ACTIVITY IN THE TREATMENT OF CHRONIC VENOUS LEG ULCERATION

An increased rate of venous ulcer healing with the use of oral enteric -coated aspirin (300 mg) daily has been reported.(1) Whether the effec t of aspirin in this condition is related to its action on the haemost atic mechanism is unclear, and therefore this study aimed to assess th e effect of aspirin on some haemostatic parameters in patients with ch ronic venous leg ulcers. A double-blind, randomized, placebo-controlle d, parallel-group study of haemostatic activity and the effect of aspi rin was implemented over a 4-month period. Twenty patients with venous leg ulcers, and 20 age- and sex-matched controls were studied. Patien ts received enteric-coated aspirin (300 mg) or placebo (one tablet) da ily for 4 months, in addition to standardized local compressive bandag ing (Setopress(R)). Assessments made at recruitment, and at 2 and 4 mo nths, included measurement of total ulcer surface area, haematological and biochemical screening, measurement of coagulation times, coagulat ion factor VIII:C (FVIII:C) and von Willebrand factor (vWF), and plasm inogen activator inhibitor-1 (PAI-1) levels. Procoagulant activity was assessed by a computer-assisted technique, to determine the rate of t hrombin production in vitro. Patients with venous ulcers had increased levels of fibrinogen (P < 0.01), FVIII:C (P < 0.05), vWF (P < 0.05) a nd PAI-1 antigen (P < 0.01) compared with controls. Shortening of the coagulation rate, shown by a reduction of the time to generate 50% max imal thrombin activity in seconds (T-50), was seen in patients, in com parison with control subjects (P < 0.05). T-50 was longer in patients receiving aspirin than those receiving placebo, reflecting prolongatio n of coagulation rate in the aspirin-treated group. In addition, an in creased rate of ulcer healing occurred in subjects receiving aspirin c ompared with the placebo-treated group (P < 0.01, P < 0.02 at 2 and 4 months, respectively). No significant change in fibrinogen, FVIII:C, v WF or PAI-1 levels occurred in either group during the 4-month period.