Dose Omission and the New Oral Anticoagulants

Tuesday, June 13, 2017
Author: 

R.L. Wynn

Two independent studies show that there is very little bleeding risk in patients undergoing dental surgery who are medicated with the new anticoagulants and that dose omission before or after dental surgery is not necessary. “New” anticoagulants include dabigatran, rivaroxaban, and epixaban and are collectively termed direct acting oral anticoagulants (DOACs).

Prospective data collected in a study out of London showed that, for patients medicated with DOACs, oral surgeons might anticipate a post-operative bleeding rate requiring additional local measures for hemostasis in as few as 6% of cases. The authors state that it is possible to safely conduct dentoalveolar procedures for patients prescribed DOACs.

A study out of Tel Aviv showed that the risk of bleeding in dental patients using DOACs is low with no major consequences. The data support not stopping DOACs prior to dental treatment, regardless of the complexity or extent of the procedure.

London Study

The first study was conducted at the King’s College Hospital, King’s College, London and can be accessed at: Patel JP, et al. “Managing direct oral anticoagulants in patients undergoing dentoalveolar surgery.” British Dental Journal 2017; 222:245-249.

The objective of the study was to describe experiences in managing a cohort of adult patients prescribed DOACs undergoing dentoalveolar procedures between November 2012 and May 2016.

Methods

The hospital had no clinical experience managing DOAC therapy during oral surgery. The department of oral surgery decided to prospectively manage each patient on a case-by-case basis. It involved consideration of the past medical history of the patient, the indication for the anticoagulant, any renal impairment and risk of bleeding associated with the planed procedure, and the risk of thrombosis if the anticoagulant was temporarily stopped.

Using the information, a specific plan was formulated for each patient, including if the DOAC should be continued as usual, omitted, or the timing of DOAC administration altered.

If any patient experienced bleeding, they were categorized according to the following:

  1. Bleeding present but no action required
  2. Patient required consultation in the dental unit, but no specific intervention was required
  3. Patient required surgical intervention (resuturing and hemostatic packing) and/or use of an antifibrinolytic, along with IV blood transfusion, replacement therapy, or desmopressin

Results

The study included 82 subjects who underwent 111 procedures while medicated with DOAC. Those procedures were:

  • Routine dental extraction: N=82 (73.9%)
  • Surgical dental extraction: N=23 (20.7%)
  • Other: N=6 (5.4%)

Categories of advice given in managing the DOAC medication:

  • Continue DOAC as per usual: N=68 (61%)
  • Omit a single dose before procedure: N= 26 (23%)
  • Omit a single dose of DOAC before and after the procedure: N=5 (5%)
  • Omit a single dose after procedure: N=3 (3%)
  • Delay the evening dose after procedure: N=8 (7%)
  • Omit for 2 days before procedure and restart the evening following procedure: N=1 (1%)

Over time and with increasing experience, advice to omit doses of DOACs became less frequent, and whenever possible, an adjustment of the timing of DOACs on the day of the procedure became more prevalent.

On the day of the procedure, the median time that elapsed between the last dose of DOAC and the start of the procedure was 15 hours, with a range of 8-20 hours. In patients who received inferior alveolar block injection for anesthesia, no bleeding or hematoma occurred at the injection site.

Persistent bleeding occurred following 15 procedures (13.5%). In six cases, the bleeding was trivial with no specific action required. Following two procedures, specific consultation in the oral surgery unit was required, but no intervention implemented. Intervention to arrest bleeding, either resuturing and hemostatic packing and/or the use of an antifibrinolytic agent, was required following the remaining seven procedures (6.3%).

Conclusion

Based on the data collected in this study, for patients medicated with DOACs, oral surgeons might anticipate a post-operative bleeding rate requiring additional local measures for hemostasis in the region of 6%.

According to the authors, it is possible to safely conduct dentoalveolar procedures for patients prescribed DOACs. To minimize post-operative bleeding and complications, it is important to consider the time the DOAC is ingested and when the procedure is planned. Oral surgeons should aim to perform the procedure when peak DOAC concentrations have subsided, i.e., 5-6 hours post last dose.

The authors cite the Scottish Dental Clinical Effectiveness Programme (SDCEP), which provides guidance on the management of dental patients taking anticoagulant drugs. The SDCEP suggests that if bleeding risks is low, treatment should be performed without interrupting the DOAC, and that if bleeding risk is high, according to a list of specified procedures, patients should be advised to miss or delay the morning dose before treatment.

Current SDCEP guidance suggests achieving this by delaying the morning dose of a DOAC for procedures with a high risk of bleeding. Consideration is also to be given as to when the DOAC is recommenced. The authors suggest waiting a minimum of 4-6 hours after the procedure and determining that hemostasis is secure. The authors recognized that optimum periprocedural strategy for managing surgery patients on DOACs has yet to be confirmed.

Tel Aviv Study

The second study was done at the Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, and can be accessed at: Zeevi I, et al. “Four-year cross-sectional study of bleeding risk in dental patients on direct oral anticoagulants.” Quintessence Int 2017; 48:503-509.

The study assessed the bleeding risk in dental patients on DOACs. The dental patient was defined as one medicated with DOACs who undertook any sort of dental activity including: dental examination, hygienist treatment, restorative procedures, and potential bleeding procedures (i.e., biopsy, extractions, dental implants, bone augmentation).

Methods

Data were collected from patients’ records. They included the type of dental procedure performed, instructions to withdraw DOAC therapy prior to treatment, and any intraoperative and postoperative complications.

Bleeding events were defined as a patients’ return to the hospital within 2 weeks of the procedure with active bleeding or the development of substantial oral or facial hematoma or ecchymosis.

Local hemostatic measures used during the surgical procedures included suture only or suture combined with either gelatin sponges, cellulose, of tranexamic acid rinse at the discretion of the surgeon.

Results

One hundred and eleven patients were included in the results.

The most frequent indication for DOACs was atrial fibrillation (81%). Rivaroxaban was the most frequent DOAC used (50%), followed by dabigatran (32%). Twenty-five patients were also taking either aspirin or clopidogrel along with the DOAC.

For those undergoing potential dental bleeding procedures (N=72), one major (1.4%) and six minor (8.3%) bleeding events were recorded. When considering all visits (115), the overall frequency of bleeding events was 6.1%.

Summarizing the seven post-operative bleeding events, six were persistent oozing, and one was facial soft tissue hematoma. No bleeding event occurred after scaling and root planing. The time between the surgical procedure and the occurrence of the bleeding event ranged from 12 hours to nine days. Five occurred after six days or more.

Local hemostatic measures were applied in all the seven cases.

The major bleeding event in the one patient consisted of persistent oozing starting six days after simple extractions of two teeth. In the emergency room, he was treated with local hemostasis by placing sutures under local anesthesia. The patient returned to the ER three more times in a time interval of 2-3 days. Each time, he exhibited persistent oozing and was treated with local hemostasis. His aspirin treatment was discontinued and DOAC dosage was reduced, resulting in bleeding resolution.

Discussion

This was one of the few studies which gathered data concerning bleeding outcomes in dental patients. The results demonstrate a low bleeding risk in dental patients on DOACs undergoing surgery.

The incidence of bleeding events in the Tel Aviv study (6.1%) was comparable to that of the King’s College study, in which the post-operative bleeding rate requiring additional local measures for hemostasis was in the region of 6%.

The data showed a significant association between postoperative bleeding and procedures involving soft tissue manipulation. Also, this study showed that withdrawal of DOACs was not associated with lower risk of post-operative bleeding. The majority of patients were continuously treated with DOACs during their dental treatment and did not experience postoperative bleeding, despite multiple and complex procedures.

The data suggest that modification of DOAC therapy for dental surgery is unnecessary, regardless of the type, complexity, or extent of the procedure. It appears that postoperative bleeding occurs infrequently and usually can be managed by simple measures with no further complications.

Whenever modification of anticoagulant therapy is considered, the potential risk of postoperative bleeding must be weighed against the risks of thromboembolic complications. After general medical surgery, the risk of major bleeding complications exceeds the risk for thromboembolic complications. In dental surgery, it is the opposite. The risk of embolic complications usually exceeds the risk of significant bleeding episodes following surgical procedures in the oral cavity.

Richard L. Wynn, BS Pharm, PhD, is professor of pharmacology at the Baltimore College of Dental Surgery, Dental School, University of Maryland Baltimore.

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