Abstract
The aim was to evaluate the management strategies of Dutch oral and maxillofacial surgeons when performing invasive dental or oral surgery in patients using oral antithrombotic medication (OAM). In November 2009 a survey was mailed to all 213 members of the Dutch Society for Oral and Maxillofacial Surgery. A response rate of 57% was achieved with 79 surveys returned through mail and 38 surveys answered through the Internet. The results show that many different treatment strategies are advocated by Dutch oral and maxillofacial surgeons, regarding preferred international normalised ratio (INR) value and continuation or discontinuation of OAM prior to invasive dental or oral surgery. The risk of bleeding during or after an invasive dental procedure was overestimated. A need for a practice guideline on this topic was expressed by 73% of respondents.
Oral antithrombotic medication (OAM) is one of the most frequently used medications in the Western world and has a proven beneficial effect in the primary and secondary prevention of cardiovascular disease, such as myocardial infarction and stroke. The most commonly used types of antithrombotics are antiplatelet medications such as acetylsalicylic acid (ASA) and vitamin K inhibitors (VKA), such as warfarin, acenocoumarol and fenprocoumon.
In the past, most dentists and oral and maxillofacial surgeons (OMSs) routinely advised their patients to discontinue these medications prior to invasive dental and surgical procedures. Recent studies have shown that the risk and sequelae of rethrombosis after discontinuation of OAM might be more harmful than the risk of a clinically significant bleeding during or after an oral surgical procedure in a patient who continues taking this medication. International guidelines for dentists on the management of patients using OAM have been published since 2007, which recommend no interruption of low-dose aspirin therapy for outpatient dental procedures and no modification of warfarin therapy for patients within therapeutic range of international normalised ratio (INR) of 3.5 or below. No official practice guideline is available in the Netherlands on this topic.
In a previous study Dutch dentists stated that they ask for advice or refer this group of patients to OMSs. The aim of the current study was to evaluate the opinion of OMSs in the Netherlands on the management of patients using OAM when performing invasive dental or oral surgery. The authors’ hypothesis is that OMSs have different opinions on this issue and thus will provide divergent advice to dentists, especially in the absence of an official practice guideline. The authors also hypothesise that there is a difference in the management of surgical procedures in patients using OAM between OMSs working in university hospitals and OMSs working in district hospitals.
Materials and methods
The Dutch Society for Oral and Maxillofacial Surgery (NVMKA) provided the authors with a list of names and addresses of all 213 OMSs practicing in the Netherlands. In November 2009, the authors sent a paper-form survey and an internet-link to an identical web-based survey to all 213 OMSs. One hundred and twenty-one surgeons anonymously returned the completed or partially completed questionnaire (57%). Four OMSs were not clinically active/working, and they were excluded from the study, leading to a sample size of 117. Seventy-nine of all OMSs who participated in the study, returned the paper-based survey (68%) and 38 took the survey digitally (32%). The percentage of males was 80%, the mean age of the entire group of respondents was 48.0 years (29–67 years), the mean clinical experience was 22 years (0–38 years). The location of their practices was equally distributed throughout the Netherlands; 64% worked predominantly in a district hospital, 22% mainly in a university hospital, and 10% in a private clinic ( Fig. 1 ).
The survey consisted of 10 questions on the topic of dental/surgical treatment of patients taking OAM ( Appendix A ). The survey was pre-tested by two general dentists and one OMS and is a modification of the survey used in a previous study. The questions were mainly structured questions with a closed answer format. When multiple answers were possible, this was stated in the question. The survey contained questions on demographic data related to active participation in patient treatment, age, gender, years of practice and working affiliation. Questions 1–3 addressed the topic of consulting medical colleagues, question 4 related to the source of current knowledge on antithrombotic medication. Question 5 focussed on the maximum advisable INR value during dental extraction and questions 6–9 asked about suggested management of patients taking OAM. Question 10 asked the OMSs for their opinion on clinical practice guidelines on dental and surgical management in patients using antithrombotic drugs.
The data were analysed with SPSS for Windows, version 15. No permission from the medical ethical committee was required to conduct this survey.
Results
Consulting medical colleagues
The majority of OMSs said they primarily contact medical specialists such as cardiologists or neurologists when seeking information on patients taking antithrombotic drugs. The warfarin clinic and the general medical practitioner scored next best as sources for consultation and only 4% stated that they did not contact any medical specialist for information on patients using OAM. The frequency of consultations is shown in Table 1 .
| Who | |
| Neurologist or cardiologist | 46 |
| Warfarin clinic | 33 |
| General medical practitioner | 16 |
| Other OMS | 1 |
| No contact | 4 |
| When | |
| Weekly | 23 |
| Monthly | 23 |
| Few times/yr | 40 |
| <once/yr | 14 |
| Last time | |
| Last week | 33 |
| Last month | 32 |
| Last 6 months | 23 |
| >6 months ago | 6 |
| > 1 year ago | 6 |
Knowledge about anticoagulants and antithrombotics
The majority of OMSs have read about oral antithrombotics in the medical literature and scientific journals. The remainder obtained their knowledge mostly in medical or dental school, by following postgraduate courses, through clinical experience, by learning from surgical or medical colleagues, or through the Internet ( Fig. 2 ).
Factors influencing clinical decisions
Most OMSs rely on their former clinical experience with the patient as the most important factor when making clinical decisions about patients taking OAMs. The extent of the surgical procedure is another important factor in the decision process. The INR value, only relevant in patients using VKA, is only considered by 2% of OMSs as an important factor in decision making ( Table 2 ).
| Former experience with this patient | 47 |
| Extent of surgical procedure | 34 |
| Underlying disease of the patient | 16 |
| INR value | 2 |
| Other | 1 |
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