Abstract
To the Editor:
Anticoagulants are used to treat individuals who are at risk for primary or recurrent thromboembolism. Patients at risk include those with mechanical heart valves, valvular heart disease, atrial fibrillation, a history of stroke, pulmonary embolus, myocardial infarction, and deep vein thrombosis. It has been common practice to discontinue anticoagulants before any surgical procedure, major or minor. Is this dogma truly supported in the literature?
As the population ages and life spans increase, the frequency of surgical procedures performed on older persons also increases, especially in the realm of cutaneous malignancies. Also, with increasing age comes the inevitable fact that more people will be on anticoagulants for many different reasons. Is it thus warranted to discontinue anticoagulants on everyone prior to surgery?
Anticoagulants
The following are the different categories of anticoagulants:
antiplatelet agents: aspirin, clopidogrel bisulfate (Plavix), and glycoprotein IIb/IIIa inhibitors
antithrombin agents: low-molecular-weight heparin (Fragmin), warfarin (Coumadin), factor Xa inhibitors (Arixtra)
thrombolytic agents: plasminogen activators (streptokinase)
Evidence
In 1993, Goldsmith and colleagues stated that there was a need to individualize the need for warfarin versus the risk of hemorrhagic complications for the particular type of surgery being contemplated. 1 It was further stated that the anticoagulant should not be adjusted without consulting whoever prescribed the medication. In general, they stated that, in most cases, warfarin could be continued without any major risk to the patient. Careful intraoperative hemostasis and postoperative pressure dressings should be used. However, it was felt that there was probably more surgical risk from continuance of aspirin than from its discontinuance. Aspirin should be discontinued 7 to 10 days prior to surgery and could be restarted as soon as 1 day postoperatively. However, if the drug is just being used as a platelet inhibitor, it would be wise to consult the patient's internist before discontinuing it.
In 1997, Billingsley and Maloney did a prospective study regarding the postoperative complications in patients on acetylsalicylic acid (ASA), warfarin, and nonsteroidal anti-inflammatory drugs and found no difference in postoperative bleeding complications between patients on these medications and controls. 2 As such, the authors concluded that there was no need to discontinue these medications in patients undergoing common dermasurgical procedures, including Mohs surgery.
In 2001, Alcalay looked at patients in his practice, 560 treated with Mohs surgery and 530 treated with excisional procedures. 3 Sixteen patients on warfarin had an international normalized ratio in the therapeutic range, and 77 patients without warfarin were used as controls. All intraoperative bleeding was easily controlled, and there was no difference in postoperative bleeding in any patient. It was recommended that warfarin be continued to lessen the chance of postoperative thromboembolic events.
In 2004, Alcalay and Alkalay, in consideration of the increased numbers of elderly and the general population using anticoagulants, performed a study to compare the risks and benefits of blood thinners in the perioperative period of patients undergoing Mohs or another cutaneous surgery. 4 This two-part study included a search of the English literature and data from clinical practice.
The results from a review of the English literature showed no increase in complications in the perioperative period. The clinical practice data were based on 2,790 patients, of whom 2.4% were on ASA. Intraoperative bleeding was easily controlled, and there were no episodes of postoperative bleeding. The authors concluded that there were no contraindications to continuing anticoagulants in Mohs surgery and other dermasurgery and that discontinuance of anticoagulants may increase the risk of cardiovascular and cerebrovascular events.
There is evidence in the literature of adverse thromboembolic events occurring postoperatively in patients who had preoperative discontinuance of their anticoagulants.5,6
In 2002, West and colleagues stated that blinded observers of cutaneous surgical procedures could not accurately predict whether patients were on anticoagulants. 7 Blinded physician evaluators observed the intraoperative ooze of 110 patients during cutaneous surgery and then rated the oozing and judged the likelihood of whether patients were on anticoagulants. Ten of 110 patients were assessed as having excess oozing and were assessed to be on blood thinners, whereas, in fact, only 4 of these 10 were actually on blood thinners. The authors thus concluded that visual inspection of intraoperative ooze is actually a poor correlator of whether a patient is on anticoagulants.
Discussion
So why do surgeons still recommend the discontinuance of anticoagulants before surgery? Most cite anecdotal experiences and believe that anticoagulants lead to undue postoperative bleeding. Is this thinking still valid? Where does this leave us? Evidence in the literature does not find significant perioperative bleeding complications in patients who maintain their anticoagulant status. However, there is evidence in the literature supporting the finding of thromboembolic events in patients whose anticoagulants were stopped. It would appear that patients who are on ASA for prevention only, not for medical reasons, can safely stop their ASA. Patients on ASA for a significant reason could be continued on their ASA unless there will be significant deep tissue resection or dissection. At this point, their prescribing physician should be consulted. Discontinuance of warfarin is, however, associated with a higher rate of thromboembolic events, so it should be continued. It would be wise in these circumstances to consult with the prescribing physician.