The evolution and impact of the American College of Chest Physicians consensus statement on antithrombotic therapy

The evolution of the American College of Chest Physicians consensus on antithrombotic therapy is reviewed, specifically with regard to the prevention and treatment of venous thromboembolism and the rules of evidence applied. A perspective on the impact of the recommendations is offered.

Safety of electrical cardioversion in patients with previous embolic events

OBJECTIVE

To assess thromboembolic complications in cardioversions in patients with atrial fibrillation or flutter and a previous embolic event.

PATIENTS AND METHODS

The study population consisted of 104 patients with previous embolic events who underwent 128 electrical cardioversions for termination of atrial fibrillation or flutter. The primary outcome measure was successful cardioversion.

RESULTS

Anticoagulants were administered in 118 procedures (92%). Cardioversion was successful in 108 (84%) of the 128 procedures. Only 1 embolic event occurred within 30 days after cardioversion (incidence, 0.9% of successful procedures; 95 % confidence interval, 0.02%-5.3%). The single embolic event was a transient neurologic deficit occurring 22 days after cardioversion in a patient with previous atrial fibrillation. This patient had a sub-therapeutic level of anticoagulation. Transesophageal echocardiography revealed no spontaneous echo contrast or thrombi before the procedure. No thromboembolism was noted in patients who had therapeutic anticoagulation or in those with failed cardioversion.

CONCLUSION

Patients with previous embolism are not at additional risk of thromboembolic complications after cardioversion if anticoagulation is adequate.

Warfarin sodium-induced skin necrosis

Skin necrosis is a rare complication of treatment with coumarin derivatives. Since it was first identified by Verhagen in 1952, approximately 200 cases of skin necrosis have been reported worldwide, but only 73 have been reported in the English language literature. A telltale clinical scenario of pain and petechiae progressing to sharply demarcated ecchymosis, bullae formation, and gangrenous necrosis manifests most often in the adipose tissues of middle-aged women. Necrosis usually appears within 3 to 6 days of the initiation of warfarin sodium therapy. We report a case of cutaneous necrosis that began 46 days after warfarin sodium therapy was begun.

Double-blind randomised trial of a very-low-dose warfarin for prevention of thromboembolism in stage IV breast cancer

Patients receiving chemotherapy for metastatic breast cancer are at high risk of thromboembolic disease. Long-term oral anticoagulant therapy is needed but increases the risk of haemorrhagic complications. We have assessed the safety and efficacy of warfarin in very low doses as prophylaxis. Women receiving chemotherapy for metastatic breast cancer were randomly assigned either very-low-dose warfarin (152 patients) or placebo (159). The warfarin dose was 1 mg daily for 6 weeks and was then adjusted to maintain the prothrombin time at an international normalised ratio (INR) of 1.3 to 1.9. Study treatment continued until 1 week after the end of chemotherapy. The average daily dose from initiation of titration was 2.6 (SD 1.2) mg for the warfarin group and the mean INR was 1.52. The mean time at risk of thrombosis was 199 (126) days for warfarin-treated patients and 188 (137) days for placebo recipients (p = 0.45). There were 7 thromboembolic events (6 deep-vein thrombosis, 1 pulmonary embolism) in the placebo group and 1 (pulmonary embolism) in the warfarin group, a relative risk reduction of about 85% (p = 0.031). Major bleeding occurred in 2 placebo recipients and 1 warfarin-treated patient. There was no detectable difference in survival between the treatment groups. Very-low-dose warfarin is a safe and effective method for prevention of thromboembolism in patients with metastatic breast cancer who are receiving chemotherapy.