ABC | Volume 111, Nº3, September 2018

Original Article Andrade et al Anticoagulation and dental procedure Arq Bras Cardiol. 2018; 111(3):394-399 Figure 1 – Bleeding scale. • 0. No bleeding • 1. Hemostasis achieved before compression measures were taken • 2. Significant bleeding on the following day • 2.1. Significant bleeding present for 48 hours • 3. Delayed bleeding Results Clinical characteristics of the sample From January to June 2017, 48 patients with nonvalvular AF were selected, and 11 patients who required no bloody dental procedure were excluded. This study included 37 patients, 19 (51.4%) of the female sex, ages ranging from 34 to 85 years (median, 69 years, IQR: 58-65 years). The patients had multiple comorbidities, such as hypertension (78.4%), diabetes (37.8%), and heart failure (27%). All patients were on regular medical follow-up and on regular use of the drugs prescribed by their attending physicians. Of the patients included in the study, 25 were selected for the warfarin group and 12, for the dabigatran group (150 mg). When comparing both groups, before the intervention, no significant statistical difference was observed regarding age, sex, race, educational level, family income, systemic blood pressure, heart rate, weight, height and number of teeth to be extracted (Table 1). Clinical outcomes Regarding the primary outcome, bleeding time 1 showed no statistically significant difference between the groups (median of 300 seconds for both groups). Regarding the other outcomes, such as bleeding time 2, bleeding before dental extraction, bleeding during dental extraction, bleeding 48 hours after the procedure, and the bleeding scale, no significant difference was found. However, bleeding 24 hours after the procedure was not identified in any patient in the dabigatran group, but eight patients in the warfarin group (32%) had it, resulting in a statistically significant difference (p=0.028) between the groups. No significant difference was observed in delayed bleeding, during and after suture removal. Table 2 illustrates the clinical outcomes of bleeding in both groups before and after the intervention. Continuous outcomes (expressed as median and 25th and 75th percentiles) were compared by use of Mann-Whitney U test. Categorical outcomes were compared by use of Fisher exact test (frequencies expected ≤ 5). Discussion This study’s results show, in individuals submitted to dental extraction, no statistically significant difference in the bleeding intensity of individuals on dabigatran as compared to those on warfarin, but suggest a lower frequency of bleeding 24 hours after the procedure in those on dabigatran. The InterFib registry has assessed 15,174 patients with AF in 47 countries, including Brazil and South America. When analyzing the data of our region, the rate of an oral anticoagulant use was 45%, of which 44% had INR within the 2-3 therapeutic range. Thus, of the patients with AF and indication for an oral anticoagulant, only 20% were properly anticoagulated. 11 There has been great controversy regarding the use of anticoagulants in planning dental treatments that involve bleeding. The major concerns about the use of NOACs in invasive dental procedures involving bleeding were the lack of a specific antidote for reversing the medicine effect and the risk of the thrombotic disease for which anticoagulation was indicated. 12 In April 2017, the Brazilian Sanitary Surveillance Agency (Anvisa) approved the use of idarucizumab in Brazil to reverse anticoagulation in patients on dabigatran. Idarucizumab is a fragment of monoclonal antibody, which, upon injection into the bloodstream, neutralizes dabigatran via direct binding, preventing its anticoagulant effect. It has been widely used in the emergency setting. The results of the RE-VERSE AD study have confirmed the efficacy and safety of that drug. More recent guidelines on the reversion of the effect of NOACs recommend its use. 13-15 Patients on oral anticoagulants for different reasons, such as AF, need to have their risk for bleeding and complications during a dental procedure assessed. The management of individuals on warfarin who need to undergo invasive dental procedures involving bleeding and/or oral and maxillofacial surgery has been well documented in the literature and follows the recommendations of the III Brazilian Guideline on Perioperative Assessment. 16 In contrast, there is no clinical trial in the literature providing specific recommendations for patients on NOACs who need to undergo dental procedures. 17 A recent study on the use of dabigatran and perioperative management has recommended not to suspend that drug in patients submitted tominor procedures, such as dental cleaning, dental extraction, skin biopsy or cataract surgery, and to perform the procedure preferably 10 hours after the ingestion of the last dose to minimize the risk of bleeding. 18 Another study has recommended not to interrupt NOACs in simple procedures, such as up to three dental extractions, three implantations, radicular scraping and smoothing, and alveoloplasties. 19 Cohen et al. 20 have reported that, for more complex periodontal surgery or more than three extractions, the medication should be suspended 48 hours before and reinitiated 24 hours after the procedure in patients with normal renal function. Breik et al. 21 have suggested that dabigatran or any anticoagulant should only be interrupted before dental procedures after consultation with the patient’s attending physician (clinician or 396