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JADA, Vol. 131, March 2000 331

Because of the risk of uncontrolled intraopera-tive or postoperative bleeding, patients receivinglong-term aspirin therapy have been asked to dis-continue use of the drug for seven to 10 daysbefore surgery.1-3 However, no double-blind con-trolled studies support this practice, particularlyfor oral surgery. Because continuous low-doseaspirin regimens have become popular in the lastdecade for treating cardiovascular and peripheralvascular diseases,4,5 patients are reluctant to stoptheir regular therapy before undergoing surgicalprocedures. Moreover, interruption of aspirin

therapy may expose these patients to the risk ofdeveloping thromboembolism, myocardial infarc-tion or cerebrovascular accident.6

We initiated this study to measure the effect oflow-dose aspirin therapy on intraoperative andpostoperative bleeding in patients undergoing oralsurgery. In addition, we compared the relation-ship between clinical hemorrhagic complicationsand the tested bleeding time.

PATIENTS AND METHODS

The study group was composed of 39 patients with

DOES LOW-DOSE ASPIRIN THERAPY COMPLICATE ORAL SURGICAL PROCEDURES?LEON ARDEKIAN, D.D.S.; RONEN GASPAR, D.M.D.; MICHA PELED, M.D., D.M.D.; BENJAMIN BRENER,M.D.; DOV LAUFER, D.M.D.

A B S T R A C T

Background. The fear of uncontrolledbleeding often prompts medical practitioners to stopaspirin intake for seven to 10 days before any surgicalprocedure. The authors initiated this study to evaluatethe effect of aspirin on bleeding in patients undergoingoral surgery.Methods. The study group consisted of 39patients who were scheduled to undergo dental extrac-tions. All patients were receiving 100 milligrams ofaspirin daily on a regular basis. The authors randomlydivided the patients into two groups: those whostopped the aspirin therapy before the procedure andthose who continued the aspirin therapy. One hourbefore the procedures, all patients underwent ableeding time test. In addition, the amount of bleedingduring the procedure was measured.Results. The mean ( standard deviation)bleeding time was 1.8 0.47 minutes for patients who

stopped aspirin therapy one week before the proce-dure. For patients who continued aspirin therapy, thebleeding time was 3.1 0.65 minutes. The differencewas statistically significant (P = .004). However, bothgroups were within the normal bleeding time range,and in both groups, a local hemostatic method was suf-ficient to control bleeding. No episodes of uncontrolledintraoperative or postoperative bleeding were noted.Conclusion. Low-dose aspirin therapy shouldnot be stopped before oral surgery. Local hemostasis issufficient to control bleeding. Clinical Implications. Patientsreceiving aspirin therapy to prevent blood clot forma-tion may be subject to emboli formation if the treat-ment is stopped. The results of this study show thataspirin therapy should be continued throughout oralsurgical procedures. Local measures are sufficient tocontrol any bleeding during surgery.

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Copyright 1998-2001 American Dental Association. All rights reserved.

a mean age ( standard devia-tion) of 62 13.2 years and anage range of 39 to 89 years. Thegroup included 15 women (meanage, 64 13.2 years) and 24men (mean age, 60 13.1 years)who were scheduled to undergodental extractions. All patientswere receiving 100 milligramsof aspirin per day on a long-term basis as a secondary pre-ventive drug for cardiovascularor peripheral vascular diseases.

We randomly divided thepatients into an experimentalgroup (19 patients) and a con-trol group (20 patients).Patients in the experimentalgroup continued to receiveaspirin therapy, while patientsin the control group stoppedaspirin therapy seven daysbefore their extraction and didnot resume treatment until theday after the surgical proce-dure. As shown in Table 1,patients in both groups were

similar in regard to the indica-tions for aspirin therapy.Anemic patients (that is, thosewith hemoglobin counts of lessthan 100 grams per liter) andpatients receiving sodium war-

farin therapy or other anticoag-ulant therapy were excludedfrom the study. The study wasapproved by the InstitutionalHelsinki Committee andinformed consent was obtained

from all patients.One of us (B.B.) performed a

bleeding time test in the Hema-tology Outpatient Clinic,Rambam Medical Center, Haifa,Israel, one hour before patientsunderwent their surgical proce-dures. The technique, describedelsewhere,7 included makingthree vertical incisions on theforearm skin with venostasis of40 millimeters of mercury.

The surgical procedures weredivided into three categories: dsimple extractions includedremoving one tooth withoutraising a mucoperiosteal flap orwithout alveoplasty; dcompound proceduresincluded extraction of a fewteeth without raising a muco-periosteal flap and with onlyminor alveoplasty; dcomplex surgical proceduresinvolved raising the mucoperio-steal flap and removing largeamounts of bone before per-forming the extraction.

Before the procedure, allpatients received a local anes-thetic (3 percent mepivacaine).

Intraoperative bleeding wasmeasured by subtracting thevolume of irrigation fluid fromthe volume of blood accumu-lated in the suction trap. Bloodloss of less than 20 milliliterswas considered mild; between20 and 50 mL, moderate; andmore than 50 mL, severe.

We used Pearsons 2 test toevaluate the relative frequen-cies of patients in differentgroups. Differences of para-metric variables were testedwith analysis of variance.

RESULTS

The mean ( SD) bleeding timewas 1.8 0.47 minutes inpatients who discontinued low-dose aspirin therapy one weekbefore oral surgery; by

332 JADA, Vol. 131, March 2000

CLINICAL PRACTICE

TABLE 1

INDICATIONS FOR RECEIVING LOWDOSE ASPIRINTHERAPY.

NO. OF PATIENTS

After MyocardialInfarction

Angina Pectoris

After CerebrovascularAccident

After CoronaryArterial BypassGraft Surgery

Deep Vein Thrombosis

Atrial Fibrillation

INDICATIONTest Group

(n = 19)Control Group

(n = 20)

7

1

4

3

3

1

5

3

6

3

3

0

The patient groupsdid not differ in thecomplexity of theoperative procedures,and the severity of intraoperative hemorrhage did notdiffer significantlybetween the groups.


comparison, patients who con-tinued aspirin therapy through-out the study period had ableeding time of 3.1 0.65 min-utes. This difference is statisti-cally significant (P = .004), butboth groups of patients werestill within the normal bleedingtime range: 1 to 4.5 minutes. Inboth groups of patients, thebleeding emanated from themucosa and the bone.

Table 2 shows the types ofsurgical procedures and theoccurrence of severe intraopera-tive bleeding. The patientgroups did not differ in the com-plexity of the operative proce-dures, and the severity of intra-operative hemorrhage did notdiffer significantly between thegroups. However, the numbersof patients with mild, moderateor severe intraoperative

bleeding, as depicted in thefigure, differed significantlybetween the two groups (P < .05). In both groups, moreintraoperative bleeding wasencountered when extractionswere complicated.

In 33 (85 percent) of the 39patients, intraoperative bleed-ing was controlled withsuturing, and local hemostasiswas achieved with directpacking with gauze. In fourpatients from the test group andtwo from the control group (onepatient underwent simpleextraction, two patients under-went a compound procedure andthree patients underwent com-plex surgical procedures), 10 percent tranexamic acid, anantifibrolytic agent that stabi-lizes the blood clot by inhibitingplasmin, was added to the localpacking, which stopped theoozing from the extraction site.Application of oxidized cellu-lose, a potent local hemostaticagent, was not required andtransfusions were not necessaryfor any of the patients. Noepisodes of uncontrolled


CLINICAL PRACTICE

TABLE 2

PROCEDURE

PATIENTS WITH SEVERE INTRAOPERATIVE BLEEDING.

* Aspirin therapy continued. Aspirin therapy stopped.

TEST GROUP (n = 19)*

SimpleExtraction

CompoundProcedure

Complex Surgical Procedure

12

5

2

CONTROL GROUP (n = 20)

No. ofPatients

Severe IntraoperativeBleeding

No. (%) of Patients

No. ofPatients

Severe IntraoperativeBleeding

No. (%) of Patients

1 (8)

1 (20)

2 (100)

9

7

4

0 (0)

1 (14)

1 (25)

16

14

12

10

8

6

4

2

0Mild Moderate Severe Mild Moderate Severe

INTRAOPERATIVE BLEEDING

NU

MB

ER

OF P

AT

IEN

TS

Aspirin Therapy Stopped Aspirin Therapy Continued

Figure. Frequency and severity of intraoperative bleeding in dentalpatients.


postoperativebleeding orother complica-tions were

reported during the week aftersurgery.

DISCUSSION

Until the early 1980s, aspirinwas used as an anti-inflamma-tory, analgesic and antipyreticdrug for short periods only. Themajor side effects of aspirinnamely, gastrointestinal irrita-tion and ulcers; tendency todevelop gingival, nasal andintestinal hemorrhage; andasthmalike attacks in asthmaticpatientslimited administra-tion of the drug to short periods(from two to five days).8

Studies conducted since theearly 1980s have shown thatthe antiplatelet effect is elicitedat low dosesof about 0.5 to 1.0 mg per kilogram per daywhile the analgesic andantipyretic effects occur only ata daily dosage of 5 to 10 mg/kg,and the anti-inflammatoryeffect is achieved at a dosage ofmore than 30 mg/kg/day.9 Thus,low doses of aspirin are suffi-cient for achieving anticoagula-tion with reduced side effects.Therefore, within the lastdecade we have seen a rapidincrease in the use of low-doseaspirin as a secondary preven-

tive drug bypatients whohave cardio-vascular andperipheral vascular dis-eases.10 Theincreasing pop-ularity ofaspirin, eitheralone or incombinationwith otherdrugs, has pre-

sented physicians and dentistswith the dilemma of whether toadvise patients to discontinueaspirin therapy before surgicalprocedures are performed.

Controversy exists in the lit-erature regarding this issue.Many studies11,12 have advo-cated stopping aspirin therapyseven to 10 days before electivesurgery.1 Conversely, otherresearchers have suggested thataspirin therapy should be con-tinued regardless of the surgicalprocedure.13,14

Lawrence and colleagues14

recommended the continuationof aspirin therapy before elec-tive dermatologic surgery if thepatients bleeding time waswithin normal limits. Theyfound that bleeding time wasprolonged in six (37.5 percent)of 16 patients receiving aspirintherapy; however, all of thesepatients had been receivinghigh doses of aspirin. Theresults of our study showed thatwhen patients received a lowdose of aspirin (100 mg), theirbleeding time remained,without exception, withinnormal limits.

On the other hand, Scher 2

advocated stopping aspirintherapy before any surgical procedure performed on a non-emergency basis. He found thatdiffuse postoperative bleeding

was associated with preopera-tive use of aspirin. However,the patients in his study werealso receiving a high dose ofaspirin.

Thomason and colleagues15

described a patient receivinglow-dose aspirin therapy whoseplatelet function was completelyimpaired, and required infusionof platelets to control hemor-rhage after gingivectomy. Theseauthors suggested that therarity of such cases points to aconsiderable variability in theindividual platelet response tothe drug.

Our study demonstrated thatdental extractions, even themore complex procedures, didnot result in uncontrolled intra-operative or postoperative hem-orrhage in patients receivinglow-dose aspirin therapy on along-term basis. No radicalsteps were needed to stop thebleeding in these patients, andin most cases suturing was theonly hemostatic tool used. Fur-thermore, the results of all ofthe patients bleeding timeteststhe only reliable test forthe activity of platelets7,16werewithin the normal range,regardless of whether patientscontinued or discontinuedaspirin therapy. Thus, it seemsthat there is no need to stoplow-dose aspirin therapy inmost patients, perhaps even inpatients with anemia. Althoughwe observed no complications inpatients in whom aspirintherapy was temporarilystopped, such discontinuationmay induce thrombogenesis.

CONCLUSION

In contrast to other studies,which involved high-dose aspirintherapy,2,14 ours was a prospec-tive study that examined thebleeding tendency of patients

334 JADA, Vol. 131, March 2000

CLINICAL PRACTICE

Dr. Ardekian is a

senior surgeon,

Department of Oral

and Maxillofacial

Surgery, Rambam

Medical Center,

Haifa, Israel, and the

Rappaport Faculty of

Medicine, Technion,

Haifa. Address

reprint requests to

Dr. Ardekian,

Rambam Medical

Center, Haifa 35254,

Israel.

Dr. Laufer is a pro-

fessor, Department

of Oral and Maxillo-

facial Surgery,

Rambam Medical

Center, Haifa, Israel,

and the Rappaport

Faculty of Medicine,

Technion, Haifa.

Dr. Peled is the

deputy head, Depart-

ment of Oral and

Maxillofacial Surgery,

Rambam Medical

Center, Haifa, Israel,

and the Rappaport

Faculty of Medicine,

Technion, Haifa.


receiving regular low-doseaspirin therapy. In light of ourresults in this preliminary, lim-ited-size study, we suggest thatthere is no need to exposepatients to the risk of thrombo-embolism, cerebrovascular acci-dent or myocardial infarctionbefore undergoing dental extrac-tions. Consequently, they shouldcontinue to receive their dailydose of 100 mg of aspirin duringthe preoperative period.

At the time this study was conducted, Dr.Gaspar was the chief resident, Department ofOral and Maxillofacial Surgery, RambamMedical Center, Haifa, Israel. He now is inprivate practice.

Dr. Brener is an associate professor anddirector, Thrombosis and Hemostasis Unit,Rambam Medical Center, Haifa, Israel, andthe Rappaport Faculty of Medicine, Technion,Haifa.

The authors are indebted to Michael Ben-Ezra, R.N., and Noami Nahir, R.N., for their

assistance in the technical aspects of thisstudy.

1. Conti CR. Aspirin and elective surgicalprocedures (editorial). Clin Cardiol1992;15(10):709-10.

2. Scher KS. Unplanned reoperation forbleeding. Am Surg 1996;62(1):52-5.

3. Speechley JA, Rugman FP. Some prob-lems with anticoagulants in dental surgery.Dent Update 1992;19(5):204-6.

4. Secondary prevention of vascular diseaseby prolonged antiplatelet treatment:Antiplatelet Trialists Collaboration. BMJ1988;296(6618):320-31.

5. Fuster V, Adams PC, Badimon JJ,Chesebro JH. Platelet-inhibitor drugs role incoronary artery disease. Prog Cardiovasc Dis1987;29(5):325-46.

6. Jafri SM, Zarowitz B, Goldstein S, LeschM. The role of antiplatelet therapy in acutecoronary syndromes and for secondary pre-vention following a myocardial infarction.Prog Cardiovasc Dis 1993;36(1):75-83.

7. Mielke CH Jr. Aspirin prolongation of thetemplate bleeding time: influence of veno-stasis and direction of incision. Blood1982;60(5):1139-42.

8. Peto R, Gray R, Collins R, et al. Ran-domised trial of prophylactic daily aspirin inBritish male doctors. BMJ 1988;296(6618):313-6.

9. Patrono C. Aspirin and human platelets:from clinical trials to acetylation of cyclooxy-

genase and back. Trends Pharmacol Sci1989;10(11):453-8.

10. Ferraris VA, Ferraris SP, Lough FC,Berry WR. Preoperative aspirin ingestionincreases operative blood loss after coronaryartery bypass grafting. Ann Thorac Surg1988;45:71-4.

11. Watson CJ, Deane AM, Doyle PT, Bul-lock KN. Identifiable factors in post-prosta-tectomy haemorrhage: the role of aspirin. BrJ Urol 1990;66(1):85-7.

12. Kitchen L, Erichson RB, SideropoulosH. Effect of drug-induced platelet dysfunctionon surgical bleeding. Am J Surg1982;143(2):215-7.

13. Ferraris VA, Swanson E. Aspirin usageand intraoperative blood loss in patientsundergoing unexpected operations. SurgGynecol Obstet 1983;156(4):439-42.

14. Lawrence C, Sakuntabhai A, Tiling-Grosse S. Effect of aspirin and nonsteroidalantiinflammatory drug therapy on bleedingcomplications in dermatologic surgicalpatients. J Am Acad Dermatol1994;31(6):988-92.

15. Thomason JM, Seymour RA, Murphy P,Brigham KM, Jones P. Aspirin-induced post-gingivectomy haemorrhage: a timely re-minder. J Clin Periodontol 1997;24(2):136-8.

16. Harker LA, Slichter SJ. The bleedingtime as a screening test for evaluation ofplatelet function. N Engl J Med1972;287(4):155-9.


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