Safety of dental implant surgery in patients undergoing anticoagulation therapy: a prospective case-control study

Objectives: Several studies have described oral surgical procedures in patients receiving anticoagulant therapy, but no prospective studies on dental implant surgery during anticoagulant treatment are currently available, and only a limited number of case reports refer to endosseous dental implant treatment in these patients. In the setting of oral surgery, it has been suggested that anticoagulant treatment is not required when the International Normalized Ratio (INR) is <4 and local haemostatic measures are applied. The purpose of this preliminary study was to evaluate the incidence of bleeding complications following surgical implant therapy in a group of 50 consecutive patients receiving oral anticoagulant therapy (warfarin) without interruption or modifications to their therapy (group A). Materials and methods: One hundred and nine otherwise healthy patients comparable for age, sex, extent and site of the implant surgical procedure formed the control group (group B). In both groups, a standard protocol of local haemostasis, including non‐reabsorbable sutures and compressive gauzes soaked with tranexamic acid, was applied. Surgeons, blind to the group allocation, performed all the procedures in an outpatient setting. Results: Two and three late‐bleeding complications were reported in group A and group B, respectively, without significant difference in the bleeding risk (relative risk = 1.45; P= 0.65; 95% confidence interval 0.2506–8.4271). These complications were managed using a compressive gauze soaked with tranexamic acid at the site of the surgical wound. Conclusion: According to our preliminary results, local haemostasis in dental implant surgery is able to prevent bleeding complications in patients on oral anticoagulants, allowing these surgical procedures to be performed on an outpatient basis. To cite this article:
Bacci C, Berengo M, Favero L, Zanon E. Safety of dental implant surgery in patients undergoing anticoagulation therapy: a prospective case–control study.
Clin. Oral Impl. Res. 22 , 2011; 151–156.
doi: 10.1111/j.1600‐0501.2010.01963.x     

Dental management of patients receiving anticoagulation or antiplatelet treatment

Antiplatelet and anticoagulant agents have been extensively researched and developed as potential therapies in the prevention and management of arterial and venous thrombosis. On the other hand, antiplatelet and anticoagulant drugs have also been associated with an increase in the bleeding time and risk of postoperative hemorrhage. Because of this, some dentists still recommend the patient to stop the therapy for at least 3 days before any oral surgical procedure. However, stopping the use of these drugs exposes the patient to vascular problems, with the potential for significant morbidity. This article reviews the main antiplatelet and anticoagulant drugs in use today and explains the dental management of patients on these drugs, when subjected to minor oral surgery procedures. It can be concluded that the optimal INR value for dental surgical procedures is 2.5 because it minimizes the risk of either hemorrhage or thromboembolism. Nevertheless, minor oral surgical procedures, such as biopsies, tooth extraction and periodontal surgery, can safely be done with an INR lower than 4.0.     

Utility of an international normalized ratio testing device in a hospital-based dental practice

OBJECTIVES: The authors aimed to evaluate the utility of an in-office international normalized ratio (INR) testing device in identifying patients with INR test values considered out of the normal range for dental procedures. METHODS: This prospective cohort study involved use of an INR testing device to obtain INR test values in the dental office for patients thought to be at risk of experiencing bleeding complications after undergoing invasive dental procedures. The authors recorded demographic, social and medical history data, as well as clinical signs and symptoms of liver disease. The authors considered an INR out of range if it was greater than or equal to 1.4 for patients with potential liver disease and greater than 3.5 for patients receiving warfarin. RESULTS: The authors completed an in-office INR test for 66 patients receiving warfarin whose INR had not been tested within the preceding 48 hours and 34 patients suspected of having liver disease. Eleven (17 percent) patients receiving warfarin and seven (21 percent) patients suspected of having liver disease had INR values considered out of range. Dental treatment was deferred for eight of 11 patients in the warfarin group who had INR values in the range of 3.6 to 7.4, while three others had dental procedures without bleeding complications. Six of seven patients who had documented or suspected liver disease and an out-of-range INR (range 1.5-2.5) underwent their dental procedures without experiencing bleeding complications. CONCLUSIONS: Use of an in-office INR test indicated a high incidence of elevated INR values. The results of this study point to the importance of obtaining current INR values before performing invasive dental procedures for patients receiving warfarin therapy whose INR values have not been tested recently, and for patients thought to be at risk of developing or having liver disease.     

Views of cardiac-valve prosthesis patients and their dentists on anticoagulation therapy

By administering a questionnaire to 253 patients with cardiac-valve prostheses (89.3% responding), and another to 136 of their attending dentists (79% responding), the level of knowledge among both groups of anticoagulant therapy in connection with dental treatment was investigated. The cardiothoracic department monitored all anticoagulation therapies. Of the anticoagulated patients, 96.6% were able to state their medication (94.1% received phenprocoumon); and of 86 dentists with patients on anticoagulation treatment, 94% were aware of their patients' medication. All 20 dentists stating that their patients did not receive anticoagulants were correct. The great majority (98%) of the dentists employed a special measure to reduce the risk of bleeding associated with invasive dental procedures, most commonly (86%) referring patients to their general practitioner or hospital department for adjustment of the anticoagulant therapy. Around 60% of the dentists considered extractions and operations to require measures to reduce the risk of bleeding complications. We recommend referral of patients to the attending physician for adjustment of anticoagulation to a target International Normalized Ratio (INR) of 4.0 or possibly 3.0 before undergoing dental procedures involving the risk of bleeding. Additional reduction of the bleeding risk can be obtained by local application of an inhibitor of fibrinolysis (tranexamic acid).     

Myths of dental surgery in patients receiving anticoagulant therapy

BACKGROUND: Continuous anticoagulant therapy with warfarin is administered to prevent a variety of medical complications, including thromboembolisms and stroke. When patients receiving continuous anticoagulant therapy are scheduled for dental surgery, a decision must be made whether to continue or interrupt the anticoagulant therapy. METHODS: The author reviewed the literature, focusing on dental surgery in patients receiving continuous anticoagulant therapy and in patients whose anticoagulant therapy was withdrawn before they underwent dental procedures. RESULTS: Of more than 950 patients receiving continuous anticoagulant therapy (including many whose anticoagulation levels were well above currently recommended therapeutic levels) who underwent more than 2,400 surgical procedures, only 12 (< 1.3 percent) required more than local measures to control hemorrhage. Only three of these patients (< 0.31 percent) had anticoagulation levels within or below currently recommended therapeutic levels. Of 526 patients who experienced 575 interruptions of continuous anticoagulant therapy, five (0.95 percent) suffered serious embolic complications; four of these patients died. CONCLUSIONS: Serious embolic complications, including death, were three times more likely to occur in patients whose anticoagulant therapy was interrupted than were bleeding complications in patients whose anticoagulant therapy was continued (and whose anticoagulation levels were within or below therapeutic levels). Interrupting therapeutic levels of continuous anticoagulation for dental surgery is not based on scientific fact, but seems to be based on its own mythology. CLINICAL IMPLICATIONS: Dentists should recommend that therapeutic levels of anticoagulation be continued for patients undergoing dental surgery. Practitioners should consult with the patient's physician if necessary to determine his or her level of anticoagulation before performing dental surgery.     

抗凝血与抗血小板治疗老年患者拔牙的临床研究

目的：观察抗凝血治疗和抗血小板治疗的老年患者拔牙术后出血及拔牙创的愈合,评价拔牙术后明胶海绵加缝合创口的止血效果。方法：老年患者分为抗凝血治疗需要拔牙组、抗血小板治疗需要拔牙组和随机选择需要拔牙的老年患者作正常对照。抗凝血治疗组拔牙前均进行凝血酶原时间国际标准化率检测。三组均采用局部纱布压迫止衄,比较拔牙术后出血情况,拔牙术后出血的病人采用局部明胶海绵加缝合创口处理。结果：抗凝血治疗与其他2组出血有显著性差异,3组均未出现局部不可控制的出血;3组创口愈合没有明显差别。结论：接受抗凝血治疗和抗血小板治疗的老年病人,在不停药和不减少药物剂量的情况下可以行拔牙术,明胶海绵加上局部缝合可达到止血目的。     

The dental patient on oral anticoagulant medication: a literature review

Specific diseases and medications may considerably influence the delivery of oral care and the course of dental therapy. The purpose of this literature review is to examine the relationship between oral anticoagulant medication and dental treatment. Electronic and manual searches were conducted for clinical studies in the English literature for the years 1988-2010. The review process provided a total of 110 pertinent literature references, out of which 38 studies dealt with oral anticoagulants and dental treatment. Different treatment strategies relative to dental periprocedural anticoagulation regimens have been identified, and their accompanying thromboembolic and bleeding risks are being presented and discussed. Regarding to what extent a safe and successful dental treatment in patients on anticoagulant medication is feasible, the level of evidence is lacking. Until high-level data are provided, an individualised treatment approach after consultation with the physician of the patient is highly recommended.     

Pretreatment management of the patient receiving anticoagulant drugs

This literature review suggests that certain low-risk dental treatment procedures can be performed in patients without altering their anticoagulant medications. Intermediate-risk dental procedures in these patients may be accomplished outside the hospital if the patient's prothrombin time value is within a specified range and if certain techniques are followed. In some cases, temporarily altering the dose of anticoagulant may be necessary. Patients receiving anticoagulant medications should continue to receive high-risk dental treatment in hospitals.     

Stop the nonsense not the anticoagulants: a matter of life and death

Many dental patients have medical problems that require the administration of oral anticoagulants to prevent catastrophic or life-threatening thromboembolic events. Examples include patients with medical conditions such as atrial fibrillation, mechanical heart valves, recent pulmonary embolism, stroke, deep vein thrombosis, anticardiolipin syndrome and coronary artery disease. The oral anticoagulant used most commonly in these instances is Coumadin. Stopping the administration of Coumadin to perform routine dental procedures can be life threatening. Many physicians and dentists believe these patients may not have routine dental procedures, including cleanings and uncomplicated extractions, while on Coumadin for fear of serious postoperative bleeding. No scientific evidence exists to support removing these patients from Coumadin to perform routine dental procedures and uncomplicated extractions, provided the patient's level of anticoagulation is within therapeutic range. Science clearly indicates that in the case of routine dental work, including uncomplicated extractions, the risk of a patient on Coumadin having a life-threatening thromboembolic event if the anticoagulant therapy is stopped is three- to five-times greater than the risk of the patient having postoperative bleeding that cannot be controlled with local measures.     

Prevention of postoperative bleeding in anticoagulated patients undergoing oral surgery: use of platelet-rich plasma gel.

PURPOSE: This study evaluated the effectiveness of a protocol using platelet-rich plasma (PRP) to prevent bleeding after dental extraction in patients treated with anticoagulant oral therapy. MATERIALS AND METHODS: Forty patients with mechanical heart-value replacement who were treated with anticoagulant oral therapy were selected for the study. Each patient was treated with PRP gel placed into residual alveolar bone after extraction without heparin administration after suspension of oral anticoagulant drugs (36 hours). RESULTS: Only 2 patients reported hemorrhagic complications (5%). Sixteen patients (40%) had mild bleeding that was easy to control with hemostatic topical agents; this mild bleeding terminated completely 1 to 3 days after the surgical procedures. The remaining 22 patients (55%) presented with adequate hemostasis. CONCLUSIONS: Oral surgery in heart surgical patients under oral anticoagulant therapy may be facilitated with PRP gel. Its use is an advanced and safe procedure. This biological and therapeutical improvement can simplify systemic management and help avoid hemorrhagic and/or thromboembolic complications.     

Educational practices regarding anticoagulation and dental procedures in U.S. dental schools

Evidence suggests that stopping oral anticoagulation with warfarin is not necessary in patients requiring low-risk dental procedures and may actually increase thrombosis risk. However, widespread belief remains among dentists that stopping oral anticoagulation for dental procedures is necessary. The purpose of this study was to investigate the teaching practice of U.S. dental faculty responsible for providing education to dental students about anticoagulation. Surveys were mailed in 2003 and 2004 to fifty-five U.S. dental faculties to assess their teaching practice regarding anticoagulation and dental procedures. Twenty-eight (50.9 percent) of the schools returned surveys. Contrary to evidence indicating anticoagulation does not need to be altered, many dental faculty responded that they teach dental students to discuss with medical providers/patients about altering warfarin therapy for several routine procedures: 21.4 percent (cleaning), 14.3 percent (restorative treatment), 46.4 percent (single simple extraction), 64.3 percent (multiple simple extractions), and 17.9 percent (root canal). However, 67.9 percent stated an International Normalized Ratio (INR) of 2.0-3.0 would be acceptable prior to dental procedures. A discrepancy was also found between the number of faculty recommending altering warfarin in intermediate- to high-risk individuals compared to those recommending heparin bridging for the same patients. Overall, this study identified inconsistencies between teaching practices in U.S. dental schools and medical evidence. Dental faculty should consider comparing their teaching material with evidence regarding anticoagulation and dental procedures. Continuing education may be necessary for practicing dentists regarding this topic.     

Dental management of a patient fitted with subcutaneous Implantable Cardioverter Defibrillator device and concomitant warfarin treatment

Automated Implantable Cardioverter Defibrillators (AICD), simply known as an Implantable Cardioverter Defibrillator (ICD), has been used in patients for more than 30 years. An Implantable Cardioverter Defibrillator (ICD) is a small battery-powered electrical impulse generator that is implanted in patients who are at a risk of sudden cardiac death due to ventricular fibrillation, ventricular tachycardia or any such related event. Typically, patients with these types of occurrences are on anticoagulant therapy. The desired International Normalized Ratio (INR) for these patients is in the range of 2–3 to prevent any subsequent cardiac event. These patients possess a challenge to the dentist in many ways, especially during oral surgical procedures, and these challenges include risk of sudden death, control of post-operative bleeding and pain.This article presents the dental management of a 60 year-old person with an ICD and concomitant anticoagulant therapy. The patient was on multiple medications and was treated for a grossly neglected mouth with multiple carious root stumps. This case report outlines the important issues in managing patients fitted with an ICD device and at a risk of sudden cardiac death.     

Haemostasis in oral surgical procedures involving patients with a ventricular assist device

The purpose of this study was to determine whether tooth extraction for patients with ventricular assist devices (VADs) could be performed without interruption of anticoagulant and/or antiplatelet therapy and whether treatment with von Willebrand factor concentrates and desmopressin is required. The study consisted of three groups of patients undergoing oral surgery. The two experimental groups comprised patients with VADs, while the third group included cardiovascular patients without VADs who served as controls. All patients were treated intraoperatively with topical haemostatic agents (oxidized cellulose or collagen). The first group was additionally treated with fibrin glue. All 75 oral surgical procedures were performed under local anaesthesia without sedation. Three of 40 patients in the experimental groups and two of 20 patients in the control group suffered a haemorrhage, with no significant difference in the incidence of haemorrhage between the groups. The findings suggest that dental extraction can be performed without modification of oral anticoagulation or antiplatelet treatments, providing that INR is less than 3.5 on the day of the operation. It can further be hypothesized that an acquired coagulopathy in VAD patients does not influence the bleeding risk in dental extractions, and so the administration of desmopressin and/or von Willebrand factor concentrates is not required.     

Lack of a scientific basis for routine discontinuation of oral anticoagulation therapy before dental treatment

BACKGROUND: There is a widespread belief among dental practitioners and physicians that oral anticoagulation therapy in which patients receive drugs such as warfarin sodium must be discontinued before dental treatment to prevent serious hemorrhagic complications, especially during and after surgical procedures. OVERVIEW: The authors examine the scientific basis for properly managing the dosage of anticoagulants for dental patients who are receiving anticoagulation therapy. The authors review the appropriate laboratory test values to which dentists should refer when evaluating for dental treatment patients who are receiving anticoagulation therapy. The authors also review clinical studies, published within the past five years, that focus on the frequency and degree of hemorrhagic and related complications among dental patients who are receiving anticoagulation therapy orally to prevent thromboembolic events. CONCLUSIONS AND CLINICAL IMPLICATIONS: The scientific literature does not support routine discontinuation of oral anticoagulation therapy for dental patients. Use of warfarin sodium as it relates to dental or oral surgical procedures has been well-studied. Some dental studies of antiplatelet therapy are consistent with the findings in warfarin sodium studies. Dental therapy for patients with medical conditions requiring anticoagulation or antiplatelet therapy must provide for potential excess bleeding. Routine discontinuation of these drugs before dental care, however, can place these patients at unnecessary medical risk. The coagulation status--based on the International Normalized Ratio--of patients who are taking these medications must be evaluated before invasive dental procedures are performed. Any changes in anticoagulant therapy must be undertaken in collaboration with the patient's prescribing physician.     

A retrospective review of clinical international normalized ratio results and their implications

BackgroundWarfarin is a key element in therapy for atrial fibrillation, deep venous thrombosis (DVT), stroke (cerebrovascular accident) and cardiac valve replacement. Often, patients’ warfarin blood levels are not tightly controlled with regard to accepted therapeutic ranges, by virtue of the drug’s unpredictable nature.MethodsThe authors searched 16,017 active clinical charts for active patients of record from the three campuses of the School of Dentistry, Marquette University (MU), Milwaukee, for the years 2009 and 2010. Dental records of 315 patients contained entries including “INR,” the abbreviation for the term “international normalized ratio.” Only 247 of those records contained an indication of whether the patient’s INR values were within therapeutic range. The authors found that 1.96 percent of the total MU dental clinic patient population had a history of warfarin use.ResultsWhen the authors compared the INR values for patients with diagnoses of atrial fibrillation, DVT, stroke and cardiac valve replacement, they found that INR values for 107 of the 247 patients (43.3 percent) were not within therapeutic range for the respective diagnoses. For example, only 50 percent of the patients being treated for atrial fibrillation presented themselves for surgical dental treatment while their INR values were in tight control.ConclusionThe INR values for a significant number of dental patients are not within the therapeutic range for their medical conditions. These patients need to seek follow-up care from their medical care providers.Clinical ImplicationsScreening for INR in the dental office—especially before invasive dental treatment such as periodontal surgery, tooth extraction and dental implant placement—can help prevent postoperative complications. It also can aid the clinician in evaluating whether a patient’s INR is within therapeutic range and, subsequently, whether the patient’s physician needs to adjust the warfarin dosage.     

富血小板血浆在抗凝治疗患者拔牙术中的应用

目的:评价富血小板血浆局部应用对抗凝治疗患者拔牙术后出血及拔牙创愈合的影响。方法:选择抗凝治疗需拔牙患者48例随机分为实验组和对照组,另外随机选择从未经抗凝治疗拔牙患者20例作正常对照。拔牙前均行凝血酶原时间和国际标准化率检测。拔牙术后实验组拔牙创置自体富血小板血浆,对照组和正常对照组拔牙创行明胶海绵填塞、可吸收线缝合或填塞加缝合处理,比较三组术后出血情况及拔牙创愈合情况。结果:实验组术后轻度出血1例,对照组术后中度出血1例,轻度出血3例,正常对照组术后轻度出血1例,三组均未出现严重出血病例;10 d后拔牙创软组织愈合实验组优于对照组和正常对照组。结论:富血小板血浆局部应用能有效预防抗凝治疗患者拔牙术后出血,促进拔牙创软组织早期愈合。     

Dental extractions in patients maintained on oral anticoagulant therapy: comparison of INR value with occurrence of postoperative bleeding

The purpose of this study was to evaluate the incidence of postoperative bleeding in patients treated with oral anticoagulant medication who underwent dental extractions without interruption of the treatment and to analyze the incidence of postoperative bleeding according to the International Normalized Ratio (INR) value. The 249 patients who underwent 543 dental extractions were divided into five groups: Group 1 with INRs of 1.5-1.99, Group 2 with INRs of 2-2.49, Group 3 with INRs of 2.5-2.99, Group 4 with INRs of 3-3.49 and Group 5 with INRs>3.5. The INR was measured on the day of the procedure. Local haemostasis was carried out with gelatin sponge and multiple silk sutures. Of the 249 patients, 30 presented with postoperative bleeding (12%): Group 1, three patients presented with bleeding (5%), Group 2, 10 patients (12.8%), Group 3, nine patients (15.2%), Group 4, five patients (16.6%) and Group 5, three patients (13%). The incidence of postoperative bleeding was not significantly different among the five groups. The value of the INR at the therapeutic dose did not significantly influence the incidence of postoperative bleeding. Thus, dental extractions can be performed without modification of oral anticoagulant treatment. Local haemostasis with gelatin sponge and sutures appears to be sufficient to prevent postoperative bleeding.     

Cardiological (pharmaco)therapy and dental practice

In recent years much progress has been made in the treatment of acute coronary syndromes, heart failure and cardiac rhythm disturbances. Polypharmacy including two antiplatelet drugs (aspirin and clopidogrel) is common in many patients after a percutaneous coronary intervention using a 'stent'. Discontinuation of these drugs for invasive dental treatment may result in coronary rethrombosis. However, in many patients with coronary artery disease, a temporal pause in the use of aspirin appears safe and may decrease the risk of bleeding after a dental procedure. An increasing number of patients with heart failure and/or life threatening rhythm disturbances receive an implantable cardioverter defibrillator (ICD). Such a device, equipped with a left ventricular lead, also stimulates the left ventricle in case of delayed electrical conduction (e.g. a left bundle branch block). This so called cardiac resynchronization therapy decreases morbidity and mortality in selected patients. ICDs are safe in the dental office even in case of discharge. In patients with prosthetic heart valves, endocarditis prophylaxis according to the current guidelines is recommended before invasive dental treatment. Dentists are advised to contact the Dutch Thrombosis Service to discuss the dose of oral ancicoagulants and the required INR value. In case of urgent and/or extended dental procedures, admittence to a hospital must be considered to secure optimal therapy.