We agree with the comments by Chow and Szeto on the use of tranexamic acid to improve hemostasis during dental procedures. Although beyond the scope of our review, the appropriate use of local measures, which may include local pressure, tranexamic acid, tannic acid (biting on tea bags), oxidized cellulose gauze, gelatin sponges, or topical thrombin, is recommended when performing dental surgery on anticoagulated patients.
We appreciate the comments by Kearon and Hirsh on the efficacy of heparin and LMWH therapy on prevention of arterial thromboembolic events. They cite recent studies as indicating that therapy with heparin or LMWH is not as efficacious as warfarin in preventing arterial thromboembolism. The overview of randomized trials listed in favor of their argument, however, is not relevant to the interruption of oral anticoagulation.1 The principal data are based on the Heparin in Acute Embolic Stroke Trial,2 which randomized patients after acute stroke associated with atrial fibrillation to aspirin or therapeutic-dose LMWH therapy. The trial found no difference in recurrent ischemic strokes at 14 days. There are several reasons this trial does not provide information on the efficacy of heparin or LMWH therapy in decreasing the incidence of perioperative thromboembolic events. First, since the study examines treatment of an acute condition, it may not be justified to extrapolate the outcomes to long-term management. Second, recurrent stroke was defined as "persistent worsening of the original deficit after the first 48 hours," rather than stroke in a new vascular distribution. The authors of the overview point out that the lack of positive findings for LMWH therapy may have been due to "inclusion of nonthrombotic causes of worsening among events." Lastly, patients in the LMWH group were denied aspirin, which is established as an effective treatment for ischemic stroke. Kearon and Hirsh also cite a review article discussing the use of LMWH for pregnant women with mechanical heart valves.3 The authors of this article discuss the limited nature of the evidence that LMWH therapy may not be efficacious and conclude that