SAN DIEGO – Whether to stop anticoagulation therapy before dermatologic surgery can be a tricky call, said Dr. Tissa Hata.
Based on the serious nature of thrombotic complications and low risk of serious hemorrhagic complications, most clinicians would agree that patients on warfarin "should have therapy continued throughout the procedure and the INR [international normalized ratio] should be within the accepted therapeutic range – usually less than 3.0," Dr. Hata said at a meeting on superficial anatomy and cutaneous surgery, sponsored by the University of California, San Diego School of Medicine and the Scripps Clinic.
Patients on aspirin, if medically necessary, "should be continued," advised Dr. Hata, professor of dermatology at the University of California, San Diego. "If aspirin is not medically necessary, the surgeon may choose to continue to discontinue. Always involve the prescribing physician in any decision to discontinue any of the medications."
She based her remarks in part on results from a prospective study of 5,950 skin cancer lesions excised in 2,394 patients (Br. J. Surg. 2007;94:1356-60). The rate of postoperative bleeding was 0.7% overall and 2.5% among the 320 patients who were taking warfarin.
The rate of bleeding was 1.0% for skin flap repairs, 0.4% for simple excision and closure, and 5.0% for skin grafts. Of the 40 cases of bleeding in the study, 26 were hemorrhages and 14 were hematomas. Three patients (two of whom were on warfarin) required exploration and one had vessel ligation. Two patients (neither of whom were on warfarin) had hematoma evacuation.
The following factors were associated with a significantly increased risk of bleeding: age greater than 67 years (odds ratio 4.7), being on warfarin therapy (OR 2.9), having undergone flap or graft surgery (OR 2.7), and having undergone ear surgery (OR 2.6).
A more recent meta-analysis representing 1,373 patients undergoing dermatologic surgery who were taking anticoagulant medications prior to surgery found that patients taking warfarin were nearly seven times more likely to have a moderate to severe complication, compared with controls (Dermatol. Surg. 2008;34:160-5). Patients taking aspirin were nearly twice as likely to have a moderate to severe complication, compared with controls.
"It does appear that warfarin and aspirin do increase your risk of bleeding and complications," Dr. Hata said. "What does that mean for us? Should we stop all of our aspirin and anticoagulants prior to procedures? What’s the risk of thrombotic complications when we stop their therapy?"
A review of studies associated with preoperative warfarin discontinuation found that the rates of thromboembolism range from 5.8%-47% within 1 month of stopping warfarin, while the yearly incidence of thromboembolism for patients with nonvalvular atrial fibrillation is 4.5% and 8% for patients with a mechanical heart valve (Dermatol. Surg. 2000;26:785-9).
According to a survey of 271 members of the American College of Mohs Micrographic Surgery and Cutaneous Oncology, 126 complications were associated with discontinuing warfarin and aspirin, most notably stroke (39 cases), transient ischemic attack (25 cases), and myocardial infarction (19 cases). More than half of respondents (56%) said that they never stop warfarin therapy prior to surgery, 41% sometimes do, and 3% always do (Dermatol. Surg. 2007;33:1189-97). In addition, 63% said that they never discontinue medically necessary aspirin prior to surgery, 34% sometimes do, and 3% always do.
Dr. Hata said that she had no relevant financial conflicts to disclose.