This document discusses the dental management of patients taking anticoagulant and antiplatelet drugs. It provides background on hemostasis and the mechanisms of action of anticoagulants like warfarin and antiplatelet drugs like aspirin. It reviews studies showing that minor dental procedures can often be performed without altering anticoagulant/antiplatelet therapy if the INR is therapeutic and local measures are used to control bleeding. For extensive procedures or supratherapeutic INRs, consulting the prescribing physician is recommended. Careful technique and local hemostatic measures can control postoperative bleeding in most medicated patients.

1. Dental Management of
Patients on Anticoagulant
and Antiplatelet Drugs
Donald A. Falace, DMD
Professor and Division Chief
Oral Diagnosis and Oral Medicine
University of Kentucky College of Dentistry

2. Normal Hemostasis
Following injury to a blood vessel:
1. Vascular retraction (vasoconstriction)
to slow blood loss
2. Adherence of platelets to the vessel
wall (endothelium) and then to each
other to form a platelet plug
3. Initiation of the coagulation cascade
resulting in the formation and
deposition of fibrin to form a clot

3. Coagulation Cascade
Extrinsic pathway:
Factor VII is activated
by tissue factor
(phospholipid) that is
released by injured
perivascular or vascular
tissues; very rapid
reaction
Intrinsic pathway:
Factor XII is activated
by exposure to collagen
from vessel wall
(endothelium) or blood
cell membrane; slower
reaction
Each activated factor, in turn,
activates the next factor-thus
the term “cascade” ultimately
resulting in the formation of fibrin

4. Anticoagulants:
– Inhibit the production of clotting factors
Antiplatelet Agents:
– Interfere with the functioning of
platelets, thus inhibiting platelet
aggregation

5. Anticoagulants
Coumarin Derivitives (dicoumarol,
warfarin: Coumadin, Panwarfin)
Coumadin antagonizes the production of vitamin K
Vitamin K is necessary for the synthesis of four of the
coagulation factors (VII, IX, X and prothrombin)

6. Pharmacologic Properties
(warfarin: Coumadin)
Taken orally
Metabolized in the liver
Half-life: 1.5-2.5 days
Duration of action: 2-5
days (it takes several days
for dosage changes to take
effect)
Increased anticoagulant
effect when combined
with:
– Antibiotics
– Aspirin
– NSAIDs
– Antifungals
– Tramadol
– Tricyclic antidepressants
– Certain herbals (gingko,
ginsing, ginger, garlic)

7. Co-morbid Conditions That Can
Contribute to Increased Bleeding
Liver disease
Kidney disease
Tumor
Bone marrow failure
Chemotherapy
Autoimmune diseases

8. Conditions for which Coumadin is prescribed
to prevent unwanted blood clotting
Prophylaxis/Treatment
of:
– Venous thrombosis (DVT)
– Pulmonary embolism
– Atrial fibrillation
– Myocardial infarction
– Mechanical prosthetic
heart valves
– Recurrent systemic
embolism

9. Laboratory Tests to Monitor the
Activity of Coumadin
Prothrombin Time (PT): time for
fibrin formation via the extrinsic
pathway-factor VII
– Test performed by taking a
sample of the Pt’s blood and
adding a reagent
(thromboplastin) and calculating
the time required to form a clot;
expressed in seconds
PT Ratio: Pt’s PT/Normal PT
Normal PT ration = 1
Problem: There is variation
among thromboplastin reagents,
therefore the results from lab to
lab are not comparable

10. Same patient- Same blood
5 different laboratories - 5 different PT Ratios!
Sample Patient’s PT Control PT PT Ratio
A 17 sec 12 sec 1.4
B 18 sec 12 sec 1.5
C 21 sec 13 sec 1.6
D 24 sec 11 sec 2.2
E 38 sec 14.5 sec 2.6

11. Solution:
International Normalized Ratio (INR)
– A mathematical “correction” that
corrects for the differences in the
sensitivity of thromboplastin reagents
– Each thromboplastin is assigned an ISI
number which is a sensitivity index
– This correction makes INR values
comparable from lab to lab
– Normal INR = 1 (an INR of 2 means
that their INR is 2 times higher than
normal)

12. Same Patient-Same Blood
Reported by INR
Sample Patient
PT
Mean
Normal
PTR ISI INR
A 17 sec 12 sec 1.4 2.8 2.6
B 18 sec 12 sec 1.5 2.4 2.6
C 21 sec 13 sec 1.6 2.0 2.6
D 24 sec 11 sec 2.2 1.2 2.6
E 38 sec 14.5 2.6 1.0 2.6

13. Recommended Therapeutic Range for Oral
Anticoagulant Therapy
(American College of Chest Physicians: Chest
1998; 114(suppl): 439-769s)
INR: 2.0-3.0
Prophylaxis or treatment of venous
thrombosis
Treatment of pulmonary embolus
Prevention of systemic embolism
Tissue heart valves
Acute MI
Atrial fibrillation

14. Recommended Therapeutic Range for
Oral Anticoagulant Therapy
(American College of Chest Physicians:
Chest 1998; 114(suppl): 439-769s)
INR: 2.5-3.5
– Mechanical prosthetic valves (high risk)
– Acute MI (to prevent recurrent MI)
– Certain patients with thrombosis and
the antiphospholipid antibody syndrome
(antibodies that interfere with the
assembly of phospholipid complexes
and thus inhibit coagulation)

15. Dental Management Guidelines
There are no uniformly accepted guidelines
for managing anticoagulated patients during
dental treatment
Previous AMA/ADA recommendation was that
it was safe to perform surgery on a patient if
the PT was 1.5-2.5x normal. This, however,
is equivalent to an INR of 2.6-5.0 depending
on the sensitivity of the various
thromboplastins; an average PT of 1.6 = INR
of 3!

16. This clinical problem is not
amenable to a “cookbook”
approach
Each patient must be
considered individually and
you must take into
consideration the risk-benefit
of stopping vs continuing
anticoagulation (they are on
anticoagulants because they
are at risk for
thromboembolism)
Your decision depends upon:
– Medical condition/stability
– Degree of anticoagulation
– Magnitude of planned
surgery
– Scientific evidence
If questionable, decision
should be a shared with
physician

17. What does the scientific
literature tell us?

18. Wahl,MJ: Myths of dental surgery in patients
receiving anticoagulant therapy JADA
2000:131;77-81
Updated a previous study (Wahl,MJ: Dental surgery
in anticoagulated patients. Arch Int Med. 1998;158:1610-1616)
and added more cases (26 studies)
A review of more than 2400 cases of
dentoalveolar surgery on more than 950
patients undergoing multiple extractions, full
mouth exts, alveoloplasties whose
anticoagulant was continued (many with INR
> than therapeutic levels)
– 12 cases (0.5%) experienced bleeding that was
uncontrollable by local measures alone
– Of these 12, 7 had an INR> than therapeutic levels
& 3 were on antibiotics
– 3 required vitamin K administration to stop the
bleeding

19. Wahl,M: Dental surgery in anticoagulated
patients Arch Int Med 1998; 158;1610-1616
Reviewed case reports of 493 patients
whose anticoagulant had been
discontinued prior to dental extractions
and other dental procedures
5 pts (1%) suffered significant adverse
outcomes
– 4 patients had fatal embolisms
– 1 patient had a non-fatal embolism

20. Devani,P: Dental extractions in patients on
warfarin: Is alteration of anticoagulant
regime necessary?
Brit JOMFS 1998;36;107-111
Compared 2 groups of extraction patients
undergoing an average of 2 extractions (range
of 1-9 teeth)
– 32 pts with anticoagulant discontinued prior to surg
with INR 1.5-2.1, and
– 33 pts with anticoagulant continued with INR of 2.3-
3.4. Local measures only for hemostasis (atraumatic
technique, sutures, gauze, etc)
None in either group had significant post-op
bleeding; 1 pt in each group required
additional local measures to control delayed
oozing

21. Campbell, JH: Anticoagulation and minor oral
surgery: Should the antibiotic regimen be
altered? JOMFS 2000; 58;131-135
Compared blood loss of 3 groups of
dentoalveolar surgery pts
– 12 pts who continued anticoagulant with INR
1.2-2.9
– 13 pts who discontinued anticoagulant 3-4
days with INR 1.1-3.0
– 10 pts who were never on anticoagulant (INR
not tested)
No significant difference in blood loss
among groups and no serious
postoperative bleeding requiring
intervention

22. Dunn, A: Perioperative management of
patients receiving oral anticoagulants
Arch Int Med 2003; 163: 901-908
Conducted a systematic review and synthesis of the
English language literature from 1966-2001
examining the perioperative management and
outcomes of patients receiving long term oral
anticoagulant therapy; included a comprehensive
review of 26 case reports and studies examining
bleeding and thromboembolism after dental
procedures (minor ext, fmx, alveolectomies)
Conclusion: Most patients undergoing dental
procedures can undergo the procedure without
alteration of the OAC regimen. The current literature
suggests that the perioperative stroke rate for
patients who have OAC withheld may be
substantially greater than would be normally
predicted

23. Conclusions
It would thus appear that most patients who are
on anticoagulant therapy (Coumadin) can
undergo minor dentoalveolar surgery without
discontinuance of anticoagulant using
local/topical measures if:
– INR is within the therapeutic range (<3.5)
– No assoc aggravating conditions (e.g. antibiotics, liver or
kidney disease)
– Planned surgery is “minor” (extractions, alveoloplasty,
biopsy)
If anticoagulant needs to be adjusted (INR>3.5),
this is the responsibility of the physician

24. Antiplatelet Agents
Normal Platelet Function
Platelets adhere to the area
of injured endothelium
(mediated by von Willebrand
factor)
Platelets adhere to each other
and form a scaffolding for fibrin
deposition (von Willebrand
factor is a carrier protein for
factor VIII)

25. Uses for Antiplatelet Drugs
Prevention of heart disease
During heart attack
Unstable angina
Following heart attack
During or following angioplasty and
stenting
Prevention of stroke or TIA
Atrial fibrillation (low risk patient)
Peripheral vascular disease

26. Antiplatelet Drugs
Aspirin (irreversible effect for life of the
platelet ~ 7-10 days)
NSAIDs (reversible effect; limited to
duration of drug)
– Cox-1 (renal blood flow, fluid/electrolyte
transport, stomach mucosal integrity,
vasomotor tone, platelet aggregation)
– Cox-2 (inflammation)
Clopidogrel (Plavix)
Ticlopidine (Ticlid)
Dipyridamole (Persantine)

27. Action of Antiplatelet
Drugs
*The life of a platelet is about 7-10 days

28. Laboratory Tests to Monitor the
Effects of Antiplatelet Drugs
Ivy Bleeding time: measures the length of time a patient
bleeds after a standardized incision.
– low reproducibility
– questionable sensitivity
– poor correlation to clinical bleeding tendency
– normal: 1-6 or 7 minutes
– conventionally, a bleeding time >20 minutes has been
considered likely to result in clinically significant bleeding
Platelet Function Analyzer (PFA-100)
– currently the most widely used autoanalyzer
– not yet available in all laboratories
– measures the time it takes to form a platelet plug across the
aperature of a capillary tube
– normals: 60-120 seconds
– guidelines not currently available for application of PFA-100
results to clinical bleeding probability

29. Antiplatelet Drugs and
Postoperative Bleeding?
Very limited literature on this topic
Most of the studies deal with aspirin
Little information available on the other
antiplatelet drugs
Most of the recommendations are based
upon clinical experience, case reports and
expert opinion

30. Aspirin and Bleeding
Pawlak,D: J Oral Surg, 36:944-7,1978 (43
pts undergoing tooth extraction)
Amrein,P: JAMA, 245:1825-8, 1981
(129 pts undergoing total hip replacement)
Ferraris,V: Surg Gynecol Obstet 156:439-
42, 1983 (52 pts having various types of
general surgery)
In all studies, aspirin was continued
All three studies found no significant
difference in perioperative or postoperative
blood loss between patients taking aspirin
and controls

31. Fijnheer,R:Nederlands tijdschrift
voor geneeshunde 2003;147(1);21-25
Medline review and analysis of all articles
from 1966-2002 on surgery and bleeding
complications due to aspirin
No clinically relevant bleeding
complications were reported for
cardiovascular, vascular, or orthopedic
surgery, or epidural anesthesia; there was
an increase in clinically non-relevant
bleeding induced by aspirin
Conclusion: There is no scientific evidence
to support the withdrawal of aspirin in
patients prior to surgery

32. Current Practice in Great Britain
Smout,J: Current practice in the use of
antiplatelet agents in the perioperative
period by UK vascular surgeons. Ann Roy
Coll Surg Engl 2003:85(2);97-101
The general consensus of opinion from
this survey suggests that most vascular
surgeons do not stop antiplatelet drugs
preoperatively

33. Expert Opinion Canada
Samama,C: Antiplatelet agents in the
perioperative period: Expert
recommendations of the French Society of
Anesthesiology and Intensive Care Can J
Anesth 2002:49(6); S26-35
Conclusion: Aspirin should not be
withdrawn in most cases
– If pt is on aspirin, clopidogrel or ticlopidine and
intraoperative bleeding is feared, a short-
acting NSAID can be temporarily substituted

34. Summary: Antiplatelet Agents
Clinical experience, expert opinion, anecdotal
reports and available studies suggest that for
most patients undergoing dentoalveolar surgery,
it is not necessary to discontinue the use of
aspirin or other antiplatelet agents if used alone.
The use of these agents is not usually associated
with significant (serious) operative or
postoperative bleeding.
If two agents are used together (e.g. aspirin and
clopidogrel), the risk for bleeding is likely
increased, and depending upon the extent of the
surgery, should be discussed with the physician

35. Local Measures to Control
Postoperative Bleeding
Careful, atraumatic surgical technique
Use of absobable hemostatic agent in
socket (e.g. Gelfoam,Avitene,Surgicel)
Careful suturing; primary closure over
sockets not essential
Post-operative pressure pack (damp
gauze for 30-60 minutes); especially
important for flap compression
May use antifibrinolytic agents:
tranexamic acid [Cyklokapron Oral] or
epsilon amino caproic acid [Amicar] as
a mouthwash or to soak pressure
gauzes

36. Antifibrinolytic Mouthrinses
Epsilon amino caproic acid (Amicar)
– Syrup (1.25 gm/5cc) , 5-10 mL QID X 7 days
– Use either as mouthwash or as a soak for the
pressure gauze
Tranexamic acid (Cyklokapron)
– Used topically as 10 mL of a 4.8% -5%
weight/volume solution as a mouthwash for 2
minutes, QID, for 7 days
– Unfortunately, the 4.8% elixir is not FDA
approved for use in the USA market

37. Additional Postoperative
Measures
For analgesia, consider use of
– Acetaminophen (Tylenol)
– Codeine
– COX 2 inhibitor (Celebrex)
Avoid drugs and herbals that increase bleeding
For continued bleeding,
– 25% Amicar soaked gauze pressure pack
– Consider intranasal desmopressin acetate (DDAVP)
spray; 2.5 ml bottle; 2 nostril sprays BID for 1-2 days;
Stimulates the release of factor VIII and vWFactor
– Vitamin K (phytonadione; AquaMEPHYTON) 2.5-25 mg
iv, im, sc, or oral