Local hemostatic measures in anticoagulated patients undergoing oral surgery. A systematized literature review1

PURPOSE: To conduct a systematized review of the literature about the main local hemostatic measures to control postoperative bleeding in anticoagulated patients. METHODS: A systematized review of literature was performed in the electronic database Medline (PubMed) without restriction of the publication date. The eligibility criteria were studies involving maintenance of the anticoagulant therapy, prospective studies, retrospective studies, randomized clinical trials, controlled clinical studies, comparative studies, multicentric studies or case-control studies. Studies discontinuing anticoagulant therapy, case reports, literature reviews, in vitro studies, animal experiments and articles written in language not compatible with the search strategy adopted in this work were excluded. RESULTS: Twenty-four articles that met the adopted eligibility criteria were selected, enrolling 3891 subjects under anticoagulant therapy. A total of 171 cases of hemorrhage was observed. Tranexamic acid was the main local hemostatic measure used to controlling of postoperative bleeding. CONCLUSION: The local hemostatic measures proved to be effective according to previously published studies. Nevertheless, further clinical studies should be conducted to confirm this effectiveness.


Introduction
In oral surgery, a number of risk factors have been associated with increased risk of bleeding, such as excessive trauma to soft tissues, non-adherence to postoperative instructions, uncontrolled hypertension, as well as anticoagulant therapy 1 .
Oral anticoagulants (OA) are drugs commonly prescribed to prevent thromboembolic events associated with important medical conditions, including deep vein thrombosis, pulmonary embolism, valvular disorders, prosthetic heart valves, dilated cardiomyopathy, coronary artery bypass graft, atrial fibrillation, cerebrovascular accident and procoagulation disorder 2 . However, these anticoagulant drugs may predispose patients to developing hemorrhage during or even after minor oral surgery, such as a simple extraction 2 .
In the past few years, altering anticoagulant therapy prior to dental surgery has been an issue of great discussion. Studies have suggested the maintenance of anticoagulant therapy associated with the use of local measures to control bleeding as a safe procedure for performing tooth extractions in anticoagulated patients. Thus, the aim of this study was to perform a systematized literature review regarding the effectiveness of local hemostatic measures to controlling postoperative bleeding in patients undergoing oral surgery without anticoagulant therapy discontinuation.

Methods
A literature search in the electronic database PubMed was conducted for articles using the following terms (DeCS/MeSH) or combinations with restriction to English, Spanish and Portuguese languages: "oral surgical procedures", "anticoagulants", and "hemostatic techniques". Posteriorly, two reviewers (FSRC and FWGC) independently evaluated the titles and abstracts of the selected articles in a first round of review. In the second round, all articles fulfilling the following eligibility criteria were included: studies involving maintenance of the anticoagulant therapy, prospective studies, retrospective studies, randomized clinical trials, controlled clinical studies, comparative studies, multicentric studies or case-control studies. Studies discontinuing anticoagulant therapy, case reports, literature reviews, in vitro studies, animal experiments and articles written in language not compatible with the search strategy adopted in this work were excluded.

Results
Initial evaluation identified 615 articles. Twenty-four articles met the eligibility criteria between 1988 and 2011 were selected ( Figure 1).   A total of 1851 men and 2040 women with a mean age of 60 years old was observed. The most used anticoagulant drug was warfarin, but the authors also mentioned the use of phenprocoumarol, acenocoumarol, ticlopidine, cilostazol and dipyridamole.  Table 3. with gauze was reported, which was associated with OC and dose modification of oral anticoagulants in one study. OC was used in two studies, and in one of them, hospitalization of one patient was required. All of the bleeding cases were easily resolved with local hemostatic measures, and systemic uses of vitamin K or fresh plasma supplementation were not necessary.

Discussion
Patients undergoing oral surgery who are under anticoagulant therapy to prevent thrombotic events have an increased risk of transoperative and postoperative bleeding, since the anticoagulant therapy has the objective to maintain INR at a therapeutic level and that leads to major bleeding in these patients 7 .
The possibility of postoperative bleeding is a concern for any patient who is under anticoagulant therapy to prevent thrombosis, and usually, these patients are asked to discontinue anticoagulants for a short period of time before surgery 8  The effectiveness of TA in anticoagulated patients undergoing oral surgery has been reported 3,9,13,14 , as well as the efficacy of fibrin glue, absorbable gelatin, collagen sponges and sutures [8][9][10] .
In the present study, TA was more effective in controlling hemorrhage when compared to OC and other local measures. The higher effectiveness of TA compared to a placebo has been previously reported by some authors 10,15 who suggested that the saliva concentration of TA after using it four times a day for rinsing is enough to reduce the incidence of postoperative bleeding complications, according to previously reported results of treatment of hemophilic patients 4,5,8,13 . There does not seem to be any statistically significant difference between a two or five day The obvious advantage of local inhibition of fibrinolysis in anticoagulated patients is the simplicity and efficacy of the treatment in addition to the lack of serious side effects. The anticoagulant therapy is not discontinued, the patient is not exposed to potential complications such as thromboembolism, and hemostasis can be achieved in a safe and fast way, without major complications as observed in a few cases.
There is controversy in the literature regarding the necessity of discontinuing anticoagulant therapy prior to oral surgery in patients who are at risk for thromboembolism.
Preliminary data of this study indicate that there is no need for discontinuing anticoagulation, as long as local hemostatic measures are used 10 .

Conclusions
Patients under anticoagulant therapy are frequently submitted to oral surgery, which is why the necessity for discontinuing or not anticoagulation poses a dilemma to dentists.
Potential risks are involved in this situation, whether it decided to discontinue the medication, which can cause thromboembolism, or maintain therapeutic dose, which can lead to hemorrhage.
Considering the data reported in the literature, discontinuing medication does not seem to be necessary, provided that dentists take precautions and use local hemostatic measures efficiently and carefully. However, further clinical studies must be conducted to confirm the effectiveness of these local hemostatic measures.
Local hemostatic measures in anticoagulated patients undergoing oral surgery. A systematized literature review