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Oral anticoagulants and dental procedures: COURSE# 1208 (AGD# 016)-2 CE credits.

UPDATED COURSE AVAILABLE ONLINE NOW!

All Continuing Dental Education courses are available to ADAA members FREE of charge at www.adaausa.org

Anticoagulants and antiplatelets are commonly used for various conditions including the treatment and prevention of cardiac disease, cerebral vascular accident, and thromboembolism, in both the inpatient and outpatient settings. As such, dental professionals will encounter many patients taking these medications. For these patients, several factors should be considered prior to a dental procedure; the indication for anticoagulant or antiplatelet therapy, bleeding risk, and thromboembolic risk must be assessed prior to interruption of therapy. Evaluating the risk versus benefit of continuing therapy can assist in determining if and when it is appropriate to interrupt therapy. Additionally, patients receiving anticoagulant and antiplatelet medications are frequently managed by different healthcare providers and specialists, so it is important to maintain open communication and inform other providers if alteration of therapy is warranted, and provide clear instructions and education to both the patient and caregivers.

The management of anticoagulant and antiplatelet therapy prior to dental procedures can be complex due to the potential to prolonged bleeding times, however recent studies and guidelines suggest that these medications can be safely continued for most minor dental procedures. (1,4) Dental professionals should still be prepared to use local measures to manage any excessive bleeding. This course will discuss the available oral anticoagulant and antiplatelet therapies available in the United States as well as the recommended management of these agents prior to dental procedures.

COURSE OBJECTIVES

Upon completion of this course, the dental professional should be able to:

* Describe the different types of oral anticoagulants and antiplatelets and the mechanisms of action.

* Evaluate the risks associated with interruption of anticoagulant and antiplatelet medications prior to dental procedures.

* Identify strategies to manage bleeding risk reduction following dental procedures.

* Outline the role of health care professionals in the management of oral health care.

GLOSSARY

Acute Coronary Syndrome (ACS)--a group of conditions involving acute decreased blood flow to the heart, including unstable angina and different types of myocardial infarctions, or heart attacks

Anticoagulant/Antiplatelet--medications used to prevent clot formation or to prevent a clot that has formed from enlarging; they work by blocking the action of clotting factors or platelets

Antifibrinolytic Agent--a medication that prevents the breakdown of fibrin in blood clots and is used to prevent excessive bleeding

Blood Clot--a thickened mass formed by platelets, which form to stop bleeding, such as at the site of a cut; a clot can also form in a blood vessel, causing decreased blood flow

Embolus (i.e. Pulmonary Embolism)--a clot that travels through the blood vessel into a smaller vessel, which obstructs circulation

Hemophilia--a hereditary disorder, that occurs primarily in males, in which the blood fails to clot normally because of a deficiency or an abnormality of one of the clotting factors

Hemostasis--a process which causes bleeding to stop

International Normalized Ratio (INR)--a standardized measure of the prothrombin time (PT), which is used to determine the clotting tendency of blood; the INR is the ratio of a patient's PT to a normal (control) sample, raised to the power of the ISI value for the reagent system used

International Sensitivity Index (ISI)--a measure of thromboplastin sensitivity to an international standard; each lot number of thromboplastin used in prothrombin or INR testing is assigned its own unique ISI value from the manufacturer

Percutaneous Intervention (PCI)--a procedure performed to diagnose or treat narrowed cardiac vessels; includes procedures such as diagnostic catheterization, cardiac revascularization, angioplasty, stent placement

Provider--use of this term within this course may indicate a patient's primary physician, cardiologist or anticoagulation clinic

Thrombocytopenia--a low platelet count which can be hereditary, alcohol or medication induced, or as a result of other disease states or chemical exposures

Thrombosis (i.e. Deep Vein; Cerebral; Coronary)--formation of a blood clot that blocks or partially blocks a blood vessel; this may lead to infarction, or death of tissue, due to a lack of blood supply

Available Anticoagulants

For many years, vitamin K antagonists (i.e. warfarin) and aspirin were the only oral therapies available for prevention of thrombosis. Several new target-specific oral anticoagulants (TSOACs) have been developed in recent years and have been shown to be safe and effective alternative agents to vitamin k antagonists. It is important for healthcare providers to stay up-to-date on available treatments, including the mechanism of actions and management of these agents.

The platelet aggregation inhibitors, such as the thienopyridines (i.e. dopidogrel (Plavix)[R]), aspirin/ dipyridamole (Aggrenox[R]), and cilostazole (Pletal[R]), prevent platelet aggregation and/or platelet activation, inhibiting adhesion of platelets and clot formation. The target-specific oral anticoagulants (TSOAC) were developed more recently, marketing convenience and potentially improving clinical outcomes for patients, and include dabigatran (Pradaxa[R]), rivaroxaban (Xarelto[R]), apixaban (Eliquis[R]) and, edoxaban (Savaysa[R]). See Table 1 for complete list of oral agents available in the United States.

Warfarin

The mainstay in the anticoagulant class for many years has been the vitamin K antagonists, or warfarin (Coumadin[R]) therapy. Warfarin acts by inhibiting synthesis of the vitamin K-dependent clotting factors II, VII, XI, and X, as well as endogenous anticoagulants protein C and S. (5-6) Vitamin K antagonists are often closely monitored and have a high bleeding risk with a narrow therapeutic range. Standardized measures such as the International Normalized Ratio (INR) are utilized to determine coagulation times in patients receiving warfarin therapy and assist in determining bleeding risk for a patient. For most indications, the target INR range is 2.0 to 3.0; although some patients, such as those with certain types of heart valve replacements, may require a higher target range of 2.5 to 3.5. Subtherapeutic levels can increase the risk of thromboembolic complications, while supratherapeutic levels can increase the risk of bleeding complications. Therefore, patients require frequent monitoring of INR, often at least every four weeks, if the INR is therapeutic and stable. (5-6)

For patients taking warfarin who are undergoing a minor dental procedure, it is recommended to continue warfarin therapy and administer a prohemostatic agent as long as the INR is less than 4.0 (4,7) Minor procedures include those such as prophylaxis, simple extractions, and local anesthetic injections (see Table 2). These procedures typically result in relatively small blood loss and can be managed with local measures. (7) Ideally, dental providers should check the INR within 24 hours prior to the procedure, but up to 72 hours prior to the procedure is acceptable if the patient's INR has been stable. (5,8) If the INR is greater than 4.0, it is recommended to consider postponing the procedure due to increased risk of bleeding. The development of Point-of-Care (POC) devices has proven useful for this purpose to provide immediate INR results, so a dental provider may proceed with the necessary dental treatment. These devices use a fingerstick sample of capillary whole blood or un-anticoagulated venous whole blood. (5) Examples of available POC devices include: Coaguchek[R] XS, Coaguchek[R] XS Plus, INRatio 2[R], etc.

In some cases, such as for certain dental surgeries, it may be appropriate to have partial warfarin therapy interruption, where the patient is instructed to hold warfarin for two or three days prior to the procedure. (2) If the patient is to undergo a procedure associated with higher bleeding risk, such as extensive surgery, root removal, or bone removal, it may be appropriate to hold warfarin therapy for up to five days prior to the procedure. (2, 9) The patient's provider or cardiologist should be contacted to assist in development of a more extensive plan, which may include using heparin or low molecular weight heparin to bridge the patient during interruption of warfarin therapy. This strategy may be used particularly if the patient is at higher risk for thrombosis.

Aspirin and Antiplatelets

A few of the more commonly used antiplatelet medications include aspirin (or acetylsalicylic acid, ASA), clopidogrel, and dipyridamole. These agents act to inhibit one or more steps of platelet formation and aggregation, and essentially cause prolongation in bleeding time. Other agents, such as the thienopyridines, work to inhibit platelet activation and aggregation, specifically by inhibiting the P2Y12 adenosine diphosphate (ADP) receptor on platelets. (10,12) The thienopyridines include clopidogrel (Plavix[R]) and prasugrel (Effient[R]). Clopidogrel is approved by the United States Food and Drug Administration (FDA) for treatment of acute coronary syndrome (ACS) as well as reduction of new stroke or myocardial infarction (Ml) in patients with a recent stroke, Ml, or established peripheral arterial disease. (10) Prasugrel is FDA approved for patients with ACS who are to be managed with percutaneous coronary intervention (PCI), to decrease the risk of thrombotic cardiovascular events. (11) Ticagrelor (Brilinta[R]) is a platelet inhibitor similar to the thienopyridines, and has been FDA approved for the same indication as prasugrel, but differs from prasugrel and clopidogrel in that it reversibly binds to the ADP receptor. (12)

Studies which have evaluated postoperative bleeding times associated with continuation or discontinuation of antiplatelets such as aspirin, clopidogrel or dipyridamole, show a low risk of bleeding with these agents. (13) Although bleeding time may be prolonged in patients that take antiplatelet agents, it may not be clinically relevant when determining the risk versus benefit of continued treatment with dental procedures. (1) Postoperative bleeding may be controlled with local measures. There are few studies evaluating the bleeding risk associated with dental procedures in patients receiving the thienopyridines, either alone or in combination with aspirin. It is also important to note that there are limited studies showing clinically significant bleeding after dental procedures with these agents. (14)

Therefore, in most patients, antiplatelet medications should not be discontinued prior to routine dental procedures or minor dental surgeries according to current guidelines and studies. (2,4,8,14) Additionally, if there is any concern for bleeding or thrombosis, particularly in those patients receiving any combination of antiplatelets or anticoagulants (ASA/clopidogrel or ASA/warfarin, etc.), it is suggested that the case be reviewed more closely to consider interruption of therapy prior to the dental procedure. (16) If necessary, these medications may be held for seven to ten days prior to a procedure, but only after consulting the patient's provider or cardiologist. (2,14)

Target-Specific Oral Anticoagulants

Newer oral anticoagulants, or target-specific oral anticoagulants (TSOAC), target a specific stage in the coagulation process and provide an alternative therapy to vitamin k antagonists, with fewer limitations in regards to frequent monitoring, dietary and drug interactions, etc. There are currently four FDA approved agents in the United States, with others in the pipeline, for use in non-valvular atrial fibrillation and treatment and prophylaxis of deep venous thrombosis/pulmonary embolism. (15,16,17,18) These agents include dabigatran (Pradaxa[R]), rivaroxaban (Xarelto[R]), apixaban (Eliquis[R]), and edoxaban (Savaysa[R]). They have been widely accepted and show increasing use as a first-line option for anticoagulation therapy. Clinicians must remain aware of the concern for risk of bleeding and should use caution, as presently there are no approved agents for reversal of their effects. Laboratory monitoring such as liver function, renal function, and complete blood count tests may still be useful when determining bleeding and thrombotic risks. Also note, these agents should not be used in patients with valvular disease, including mechanical prosthetic heart valve replacements, due to increased risk of adverse outcomes, including valve thrombosis, myocardial infarction, stroke, and bleeding. (15,19)

Dabigatran (Pradaxa[R]) is a direct thrombin inhibitor, which inhibits thrombin from converting fibrinogen to fibrin in the coagulation cascade, thereby preventing formation of a dot. (15) Rivaroxaban (Xarelto[R]), Apixaban (Eliquis[R]), and Edoxaban (Savaysa[R]), are factor Xa inhibitors which block the active site of factor Xa to prevent activation of factor Xa in the coagulation cascade. (15,16,17,18)

Strong evidence and The American Academy of Neurology recommends that stroke patients undergoing dental procedures continue taking aspirin or warfarin for stroke prevention. (21) Although limited studies address specific recommendations with regards to interruption of TSOAC, for minor or low risk bleeding procedures it is generally appropriate to continue therapy. If deemed appropriate to interrupt the TSOAC, a short interruption or dosage adjustment may be considered depending on risk of procedure and patient thromboembolic risk. [20] For surgical or invasive procedures associated with low or moderate to high bleeding risk and those patient's with poor renal function, it would be prudent to defer to the individual manufacturer guidelines regarding interruption of therapy. (15,16,17,18)

Bleeding Complications versus Thromboembolic Complications

When an anticoagulant or antiplatelet medication is interrupted prior to a dental procedure, there is an increased risk for thromboembolic events. (22) However, if these medications are continued patients are at an increased risk of bleeding, as these agents impair clotting, which may result in postoperative bleeding and complications.

Thrombosis is the formation of a blood clot that blocks or partially blocks a blood vessel. Types of thromboses are named by their location including cerebral, deep vein and coronary. Postoperative bleeding complications may lead to infarction or death of tissue due to a lack of blood supply. Therefore, it is important to first weigh these factors (bleeding risk versus thromboembolic risk) prior to deciding if anticoagulant therapy should be interrupted. Wahl has studied the impact of stopping and continuing anticoagulant therapy in dentistry. (23) The thromboembolic event risk associated with interruption of anticoagulant therapy varies from 0.02 to 1% in clinical trials. According to the several consensus guidelines, anticoagulant and antiplatelet therapy can safely be continued for most minor dental procedures listed in Table 2. (2,4,7,8) It has also been shown that interruption of therapy may put patients at an increased risk for a thromboembolic event. (22)

General guidance can be provided using certain assessment tools with regards to bleeding risk and thromboembolic risk, but individual management may vary depending on procedure type and patient characteristics. Several tools have been developed to assess the bleeding risk and thromboembolic (i.e. stroke) risk of patients taking anticoagulation therapy. Bleeding risk assessments often account for patient factors such as hypertension, abnormal liver or renal function, stroke history, bleeding predisposition, labile INRs on warfarin, age greater than 65 years old, and drugs or alcohol use. The final score estimates the risk of having a major bleeding event based on patient factors. One example of a bleeding risk assessment tool often used for patients with atrial fibrillation is the HAS-BLED. (24) In patients who receive anticoagulant or antiplatelet therapy for atrial fibrillation, a provider may utilize a more extensive assessment tool to evaluate stroke risk. These assessments are referred to as the CHADS2 and [CHA.sup.2][DS.sup.2]-VASc scores. (2,5) These tools assess patient factors such as history of alcohol abuse, renal or hepatic insufficiency, gender, history of diabetes, history of stroke, age range 65 to 74 or greater than 75 years old, history of vascular disease, uncontrolled hypertension or CHF, and history of excessive falls.

Dental Treatment Considerations

The main discussion at hand is the consideration for interruption of anticoagulants or antiplatelet agents for planned dental treatment. For patients who are receiving warfarin or low-dose aspirin and need to undergo simple extractions or oral surgeries, it is recommended to continue these agents and manage bleeding with hemostatic measures unless the INR is greater than 4.0. (1,2) As previously discussed, if the INR is greater than 4.0, it is recommended to consider rescheduling the procedure. TSOACs such as dabigatran, rivaroxaban, apixaban, and edoxaban, may be continued for most minor dental procedures as well. (20)

Overall, it is important to consider the bleeding risk that may be associated with the dental procedure (see Table 2) and the medication. (2,7) The recommendation to continue anticoagulant or antiplatelet therapy may be extended to other dental procedures including crowns, bridges, root canals, extraction of limited number of teeth, implants, gingival surgery, and supragingival or subgingival scaling. (25) If the patient is to undergo a procedure associated with higher bleeding risk, such as extensive surgery, root removal, or bone removal, it may be appropriate to hold warfarin therapy for up to five days prior to the procedure (2) 9 or hold the TSOAC per the package insert recommendations. (20) It is important to inform the patient's provider, who is managing anticoagulant therapy, when warfarin or TSOAC is going to be held for a procedure. Additionally, if the dental procedure is high risk or the patient is at high risk, it may be advisable to contact the patient's cardiologist prior to interruption of therapy. In patients with liver impairment, alcoholism, kidney failure, thrombocytopenia, hemophilia, or other hemostatic disorders, it is also advisable to consult the patient's physician (4)

The risk of bleeding associated with dipyridamole/aspirin is similar to aspirin alone, and although there is less data available, dopidogrel, prasugrel, and ticagrelor may be continued as recommended with warfarin and aspirin therapies. (2,14)

Management of Bleeding

When a patient is on an anticoagulant or antiplatelet agent, it takes longer for primary hemostasis to occur; subsequently bleeding time is prolonged. (25) These medications can essentially double bleeding times, however the clinical relevance of this is minor. In most cases, hemostatic measures can be utilized to control bleeding, as significant or life threatening bleeding after dental surgery is rare. (1) Clinically significant bleeding following a dental procedure has been defined as bleeding that continues beyond 12 hours, causes the patient to call or return to the dental practice or other provider, results in the development of a large hematoma or bruising within the oral soft tissues, or requires a blood transfusion. (9) As previously mentioned, if a patient is on warfarin therapy, obtaining an INR up to 24 to 72 hours prior to the procedure is advisable.

In a study conducted by Wahl, the incidence of serious bleeding problems in 950 patients receiving anticoagulation therapy undergoing 2400 individual dental procedures was evaluated. (22) Only 12 patients (less than 1.3%) experienced bleeding uncontrolled by local measures and none of the patients reported serious harm. Further details of those 12 patients include the use of postoperative antibiotics which may have interacted with warfarin, higher than recommended anticoagulation levels, and use of mouthwash immediately after the procedure. Of note, the use of mouthwash or rinse is contrary to standard advice for 24 hours after a procedure.

For many procedures, local measures may safely be used to control any bleeding. Local hemostatic measures may include using gelatin sponges with silk sutures, vasoconstrictors in local anesthetic, and the use of antifibrinolytics. Currently available antifibrinolytic agents in the United States include tranexamic and aminocaproic acid solutions, however their use in dentistry has been controversial and are considered off-label. Tranexamic acid was initially approved in December 1986 for use in patients with hemophilia to reduce or prevent hemorrhage during and after surgical procedures. The tranexamic acid solution for injection has been used in other conditions and to reduce blood loss for those with major surgeries such as cardiac, orthopedic, etc. (26) Tranexamic acid solutions can be expensive and difficult to obtain. An alternative is aminocaproic acid solution, which is also used in the prevention of bleeding during and following procedures. Patients utilizing either agent are encouraged to hold the solution in the mouth instead of using as a mouthwash. The tranexamic acid is used by holding 10 milliliters in the affected area for two minutes prior to the procedure and repeated every two hours postoperatively for six to ten doses. For the aminocaproic acid solution, 10 milliliters should be held in the mouth for two minutes and then the patient should be instructed to expectorate. This may be repeated every six hours for two days after the procedure. (26) After any dental procedure, the patient should be educated on general measures which include:

* Rest for two or three hours

* Avoid hot liquids, rinsing the mouth, using mouthwash, or eating hard foods for 24 hours

* Avoid Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) such as ibuprofen, naproxen, etc., for at least 24 hours after the procedure

* Avoid chewing on the affected side for at least one to two days

* Do not rinse for 24 hours

* If antibiotics are required, ensure patient contacts his/her anticoagulation clinic for review of drug interaction with warfarin or other prescription medications therapy.

Role of Healthcare Professionals

It is important to encourage proper dental hygiene and preventative care to minimize the need for more intensive dental procedures. The dental healthcare team should also be aware of other pre-existing conditions which may result in bleeding complications, such as liver disease, renal disease, thrombocytopenia, hemophilia, etc. In these cases, it may be prudent to contact the patient's provider to discuss options prior to dental procedures, particularly those with higher bleeding risk. Patients should be instructed on proper dental hygiene such as:

* Gently brush teeth, gums with an extra-soft toothbrush after every meal and before bed. May soften toothbrush bristles in warm water.

* Avoid use of toothpicks.

* Floss gently every day, avoid areas where gums may be sore or bleeding.

SUMMARY

The general classes of antiplatelets and anticoagulants, including warfarin and the newer target-specific oral agents used in the prevention of thromboembolic diseases can increase a patient's bleeding risk. Bleeding complications do not carry the same risk as thromboembolic complications, as patients who interrupt these medications prior to procedures are at a higher risk for stroke or myocardial infarction. If anticoagulation therapy interruption is deemed appropriate, depending on the individual patient and/or procedure dynamics, it should be managed by an anticoagulant clinic, cardiologist, hematologist, or primary physician. (2,25)

In summary, most dental procedures may be performed without interruption in these types of medications with the use of hemostatic measures to control bleeding if needed. (2,9,25) The practice of using antifibrinolytic rinses, suturing, and pressure can be successful in the treatment of bleeding. It is advisable in the use of warfarin to monitor the patient's INR levels 24 to 72 hours prior to dental procedure. For those patients with INRs greater than 4.0, postpone dental surgical procedures and refer patient to a clinician responsible for their anticoagulation management.

REFERENCES

(1.) Jeske AH, Suchko GD. Lack of a scientific basis for routine discontinuation of oral anticoagulation therapy before dental treatment. JADA. 2003;134:1492-1497.

(2.) Douketis JD, Spyropoulos AC, Spencer FA, et al. Perioperative Management of Antithrombotic Therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. CHEST 2012; 141(2) (Suppl):e326S-e350S.

(3.) Lockhart PB, Gibson J, Pond SH, Leitch J. Dental management considerations for the patient with an acquired coagulopathy: part II: Coagulopathies from drugs. Br Dent J. 2003;195:495-501.

(4.) Anticoagulant, Antiplatelet Medications and Dental Procedures, n.p. American Dental Association. Accessed August 2015 <http://www.ada.org/en/member-center/oralhealth-topics/ anticoagulant-antiplatelet-medications-and-dental>.

(5.) Ageno W, Gallus AS, Wittkowsky A, et al. Oral Anticoagulant Therapy: Antithrombotic Therapy and Prevention of Thrombosis, 9th ed American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. CHEST 2012; 141 (2)(Suppl): e44S-e88S.

(6.) Coumadin[R] [prescribing information]. Princeton, NJ: Bristol-Myers Squibb Company; 2011.

(7.) "Suggestions for anticoagulation management before and after dental procedures." n.p. University of Washington Medical Center Anticoagulation Clinics. April 2012. <http://www.uwmcacc.org/dental procedures.html>.

(8.) Perry DJ, Nokes TJ, Heliwell PS, et al. Guidelines for the management of patients on oral anticoagulants requiring dental surgery. Br Dent J 2007, 389-393.

(9.) Lockhart PB, Gibson J, Pond SH and Leitch J. Dental management considerations for the patient with an acquired coagulopathy. Part 1: Coagulopathies from systemic disease. Br Dent J 2003; 195:439-45.

(10.) Plavix [prescribing information], Bridgewater, NJ: Bristol-Myers Squibb/Sanofi Pharmaceuticals Partnership; 2015.

(11.) Effient [prescribing information], Indianapolis, IN: Eli Lilly and Company; 2015.

(12.) Brilinta [prescribing information]. Wilmington, DE: AstraZeneca; 2015.

(13.) Napenas JJ, Hong CH, Brennan MT, et al. The frequency of bleeding complications after invasive dental treatment in patients receiving single and dual antiplatelet therapy. J Am Dent Assoc. 2009; 140(6):690-695.

(14.) Grines CL, Bonow RO, Casey DE, et al. Prevention of Premature Discontinuation of Dual Antiplatelet Therapy in Patients With Coronary Artery Stents. Circulation 2007, 115:813-818.

(15.) Pradaxa [prescribing information], Ridgefield, CT: Boehringer Ingelheim Pharmaceuticals, Inc.; 2015.

(17.) Eliquis [prescribing information]. Princeton, NJ: Bristol-Meyers Squibb, Inc; 2015.

(18.) Savaysa [prescribing information]. Edison, NJ: Daiichi Sankyo, Inc.; 2015.

(19.) Eikelboom JW, Connolly SJ, Brueckmann M, et al. "Dabigatran versus warfarin in patients with mechanical heart valves". The N Eng Journal of Medicine. 2013. 369(13):1206-1214.

(20.) Douketis JD. Pharmacologic properties of the new oral anticoagulants: a clinician-oriented review with a focus on perioperative management. Curr Pharm Des. 2010;16(31): 3436-3441.

(21.) Armstrong MJ, Gronseth G, Anderson DC, et al. Summary of evidence-based guideline: Periprocedural management of antithrombotic medications in patients with ischemic cerebrovascular disease. Report of the Guideline Development Subcommittee of the American Academy of Neurology. Neurology 2013;80:2065-9. Accessed October 9, 2013.

(22.) Wahl MJ. Dental surgery in anticoagulated patients. Arch Intern Med 1998; 158:1610-6.

(23.) Wahl MJ. Myths of dental surgery in patients receiving anticoagulant therapy. JADA. 2000;131:77-81.

(24.) Pisters R, Lane DA, Nieuwlaat R, et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest. 2010; 138:1093-1100.

(25.) Pototski M, Amenabar JM. Dental management of patients receiving anticoagulation or antiplatelet treatment. J Oral Sci 2007; 49: 253-8.

Ashley N. Castelvecchi, PharmD, CGP

Ashley N. Castelvecchi, PharmD, CGP is a Clinical Pharmacy Specialist for the Home-Based Primary Care program at the Veterans Affairs Outpatient Clinic in Greenville, South Carolina. She has a Doctor of Pharmacy from the University of Kentucky and completed a Post-Graduate Year One Clinical Pharmacy Residency at the Veterans Affairs Medical Center in Lexington, Kentucky.

Lamonica N. Crump, PharmD

Lamonica N. Crump, PharmD is a Clinical Pharmacy Specialist at the Veterans Affairs Outpatient Clinic in Greenville, South Carolina. She has a Bachelor's of Science and a Doctor of Pharmacy from the University of South Carolina.

WJB Dorn VA Medical Center, 6439 Garners Ferry Road, Columbia, SC, 29205

Greenville VA Outpatient Clinic, 41 Park Creek Drive, Greenville, SC, 29605 Current ADAA members are eligible to take this course for continuing education credit online at: www.adaausa.org. FREE OF CHARGE. There is no grading fee for the on-line test for ADAA members.

The grading fee for processing this paper test is $10. Tests not accompanied by a #10 self-addressed stamped envelope and the correct fee WILL NOT BE GRADED OR RETURNED.

The DEADLINE for tests to be submitted to the ADAA for grading is August 31, 2016. Tests received after this date will not be graded or returned.

Choose the one best answer.

1. Anticoagulant medications are used for the treatment and prevention of --.

A. Nonvalvularatrial fibrillation

B. Cancer

C. Asthma

D. Prevention and treatment of Thromboembolism

E. A and D

2. Patients receiving anticoagulant medications are frequently under the additional care of different healthcare providers and specialists. Hemostasis is a hereditary bleeding disorder.

A. Both statements are true.

B. The first statement is true. The second statement is false.

C. The first statement is false. The second statement is true.

D. Both statements are false.

3. -- will prevent platelet activation, inhibiting adhesion of platelets and clot formation.

A. Vitamin Kantagonists

B. White blood cells

C. Warfarin

D. Platelet aggregation inhibitors

4. For most people receiving warfarin, the target INR range is from --.

A. 2.0-3.0

B. 1.5-2.0

C. 2.0-4.0

D. 2.3-3.5

5. Dental procedures such as sub gingival scaling and regional injections of local anesthetic are considered -- risk.

A. low

B. moderate

C. high

D. severe

6. Ideally, dental providers should receive an INR within -- hours prior to the procedure, but up to -- hours prior if the patient's

INR has been stable.

A. 12/18

B. 18/24

C. 24/72

D. 36/48

7. The Agent Class for aspirin is a vitamin K antagonist. Aspirin blocks the aggregation of platelets and works to reduce blood viscosity.

A. Both statements are true.

B. The first statement is true. The second statement is false.

C. The first statement is false. The second statement is true.

D. Both statements are false.

8. Patients may indicate their dosage of -- is any where from 1mg-10mg/daily.

A. Coumadin

B. Plavix

C. Aspirin

D. Pradaxa

9. If a patient's INR is greater than --, it is recommended to consider postponing the procedure due to increased risk of bleeding.

A. 2.0

B. 3.0

C. 3.5

D. 4.0

10. In some cases, such as for certain dental surgeries, it may be appropriate to --.

A. increase anticoagulant

B. interrupt anticoagulant therapy

C. maintain the regular treatment plan

D. none of the above

11. A few of the more commonly used antiplatelet medication(s) include --.

A. aspirin

B. acetylsalicylic acid

C. dipyridamole

D. All of the above

12. A(n) -- may lead to infarction, or death of tissue, due to a lack of blood supply.

A. thrombosis

B. embolism

C. thrombin

D. hematoma

13. When an anticoagulant or antiplatelet medication is discontinued prior to a dental procedure, there is an increased risk of thromboembolic events. According to the several consensus guidelines, anticoagulant and antiplatelet therapy can safely be continued for most minor dental procedures.

A. Both statements are true.

B. The first statement is true. The second statement is false.

C. The first statement is false. The second statement is true.

D. Both statements are false.

14. Bleeding risk assessments often account for patient factors such as --.

A. history of diabetes

B. prior gastro intestinal bleeding

C. history of stroke and/or a history of myocardial infarction

D. All of the above

15. When a patient is on an anticoagulant or antiplatelet agent, it takes -- for primary hemostasis to occur.

A. a shorter time

B. a normal amount of time

C. a longer time

16. Clinically significant bleeding following a dental procedure has been defined as bleeding that --.

A. bleeding that continues beyond 2 hours

B. bleeding that causes the patient to call or return to the dental practice

C. bleeding that results in the development of a blood clot

D. All of the above

17. The use of mouthwash is -- for 24 hours after dental treatment.

A. not recommended

B. recommended

C. standard

D. supported

18. Local hemostatic measures may include using --.

A. gelatin sponges with silk sutures

B. vasoconstrictors in local anesthetic

C. antifibrinolytics

D. All of the above

19. After any dental procedure, the patient should be educated on such general measures that include avoiding --.

A. hot liquids

B. rinsing the mouth for 24 hours

C. eating hard foods for 24 hours

D. All of the above

20. Patients on anticoagulant therapy should be instructed to --.

A. avoid flossing

B. avoid brushing with a soft bristle brush

C. avoid toothpicks

D. avoid regular dental checkups

21. Of the target specific anticoagulant class, which agent is a direct Thrombin inhibator?

A. Eliquis(apixaban)

B. Coumadin (warfarin)

C. Pradaxa(dabigatran)

D. Pletal (cilostazole)
TABLE 1--Oral Anticoagulant/Antiplatelet Agents available
in the United States

Agent Class       Name                        Available dosage

PLATELET          Ticlid (ticlopidine)        250mg tablet
AGGREGATION
INHIBITORS        Pletal (cilostazole)        50mg, 100mg tablet

                  Trental (pentoxifylline)    400mg tablet

                  Plavix (dopidogrel)         75mg

                  Effient (prasugrel)         5mg, 10mg

                  Brilinta (ticagrelor)       90mg

                  Persantine (dipyridamole)   25mg, 50mg, 75mg

                  Aspirin                     81 mg, 325mg

                  Aggrenox                    25mg-200mg
                  (aspirin/dipyridamole)

ANTICOAGULANT     Coumadin (warfarin,         1 mg, 2mg, 2.5mg,
VITAMIN K         jantoven)                   3mg, 4mg, 5mg, 6mg,
ANTAGONIST                                    7.5mg, 10mg

ANTICOAGULANT     Pradaxa (dabigatran)        75mg, 150mg
DIRECT THROMBIN
INHIBITOR

ANTICOAGULANT     Xarelto (rivaroxaban)       10mg, 15mg, 20mg
FACTOR Xa
INHIBITOR         Eliquis (apixaban)          2.5mg, 5mg

                  Savaysa (edoxaban)          15mg, 30mg, 60mg

Agent Class       Mechanism

PLATELET          platelet aggregation and/or
AGGREGATION       platelet activation inhibitor that
INHIBITORS        blocks the aggregation of
                  platelets; reduces blood viscosity

ANTICOAGULANT     inhibiting synthesis of vitamin K
VITAMIN K         dependent clotting factors which
ANTAGONIST        include factors 2, 7, 9 and 10, and
                  the anticoagulant proteins C and S

ANTICOAGULANT     competitive, direct thrombin
DIRECT THROMBIN   inhibitors which prevent thrombus
INHIBITOR         development. As well, it inhibits
                  both free and clot-bound thrombin
                  as well as thrombin-induced
                  platelet aggregation

ANTICOAGULANT     selectively inhibits factor Xa
FACTOR Xa
INHIBITOR

* the above table is inclusive of oral agents; excludes
injectables or intravenous agents

TABLE 2--Bleeding Risk and Associated Dental Procedures

              LOW BLEEDING RISK         MODERATE BLEEDING RISK

Procedures    Supragingival scaling     Subgingival scaling
              Simple restorations       Restorations with
              Local anesthetic          subgingival
              injections                preparations Standard
                                        root canal therapy
                                        Simple extractions
                                        Regional injections of
                                        local anesthetics

Suggestions   Do not interrupt          Interruption of
              warfarin tx Use local     warfarin therapy is not
              measures to prevent or    necessary Use local
              control bleeding          measures to prevent or
                                        control bleeding
                                        Dentist to determine
                                        comfort with use of
                                        local measures to
                                        prevent bleeding when
                                        anticoagulation is not
                                        interrupted

              HIGH BLEEDING RISK

Procedures    Extensive surgery
              Apicoectomy (root
              removal) Alveolar
              surgery (bone removal)
              Multiple extractions

Suggestions   May need to reduce INR
              or return to normal
              hemostasis Use local
              measures to prevent or
              control bleeding
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Title Annotation:CONTINUING EDUCATION
Author:Castelvicchi, Ashley N.; Crump, Lamonica N.
Publication:The Dental Assistant
Date:Jul 1, 2016
Words:5499
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