Single dose of acetylsalicylic acid prevents thromboxane release after tourniquet ischemia

Background:. Ischemia, such as that caused by a tourniquet, stimulates thromboxane (Tx) A(2) synthesis. TxA(2) might sensitize the operated limb to various complications, such as compartment syndrome and thromboembolic events. Methods: We studied the effect of pretreatment with a single dose of acetylsalicylic acid (ASA) (25, 100, and 500 mg) given 3 hours before surgery on the formation of TxB(2), a stable metabolite of TxA(2), after tourniquet deflation in 32 knee or ankle surgery patients. Results: Tourniquet time varied between 60 +/- 8 to 71 +/- 7 (SE) minutes. In control patients without ASA pretreatment, the platelet-produced femoral vein serum TxB(2) concentration over 30 minutes in vitro coagulation increased remarkably (from 40.0 +/- 20 ng/mL to 73.5 +/- 39 ng/mL) immediately after tourniquet deflation. Plasma concentrations in-creased similarly, approximately threefold. Pretreatment with 100 or 500 mg ASA prevented the increase in TXB2 concentrations. Radial artery concentrations of TxB(2) were similar to venous concentrations in the different treatment groups. Conclusion: Pretreatment with a single 100-mg dose of ASA prevents the release of TxB(2) after tourniquet deflation.