Assessment of bleeding during minor oral surgical procedures and extraction in patients on anticoagulant therapy.

INTRODUCTION: The risk of postoperative hemorrhage from oral surgical procedures has been a concern in the treatment of patients who are receiving long-term anticoagulation therapy. A study undertaken in our institution to address questions about the amount and severity of bleeding associated with minor outpatient oral surgery procedures by assessing bleeding in patients who did not alter their anticoagulant regimen. SUBJECTS AND METHODS: Eighty-three patients receiving long-term anticoagulant therapy visited Department of Oral and Maxillofacial Surgery from May 2010 to October 2011 for extractions and minor oral surgical procedures. Each patient was required to undergo preoperative assessment of prothrombin time (PT) and measurement of the international normalized ratio. Fifty-six patients with preoperative PT values within the therapeutic range 3-4 were included in the study. The patients' age ranged between 30 and 75 years. Application of surgispon was done following the procedure. Extraction of teeth performed with minimal trauma to the surrounding tissues, the socket margins sutured, and sutures removed after 5 days.
RESULTS: There was no significant incidence of prolonged or excessive hemorrhage and wound infection and the healing process was normal.

Minor oral surgical procedures (MOS) in patients under anticoagulation therapy is a top listed controversy among the oral and maxillofacial surgeons (OMFS) because of the high risk they might encounter later due to the postoperative bleeding, which can be fatal. Various protocols are being employed in order to avoid untoward effects during and after MOS procedures. Though different authors voice different opinions, majority of them recommend continuation of anticoagulation therapy on and after the procedure without any alteration in the regime.[12] Clinical trial based evidence suggests postoperative bleeding in patients under Anticoagulant and antiplatelet therapy can be effectively controlled by the usage of local hemostatic agents.[3]

Subjects and Methods

Ninety-one patients receiving long-term anticoagulant therapy visited our center from May 2010 to October 2011 for extractions and MOS. Each patient was required to undergo preoperative assessment of prothrombin time (PT) and measurement of the international normalized ratio (INR).[45] An initial check of PT and INR was done on the day of the visit, and another on the day of the procedure after 3 days. Eighty-three patients with preoperative INR between 3 and 4 obtained on the day of surgery were included in the study. Opinion and consent from their respective treating physician was sought before initiating the procedure. All the patients were informed about the study and consent obtained. Eight patients whose INR were not within the therapeutic range were excluded from the study. Patients with the other coagulopathy, within 6 months of MI, liver disease, birth control pills, hormone replacement therapy, infection at surgical site and patient on nonsteroidal antiinflammatory drugs were also excluded from the study. The patients’ age ranged between 30 and 75 years. Blood pressure was recorded for all the patients prior to administration of anesthetic. About 2% lignocaine with 1:80000 adrenaline was used as a local anesthetic. Injection was administered slowly after aspiration was found to be negative. Procedures included dental extractions that were limited to 1–3 teeth in the same quadrant, surgical extraction, soft tissue biopsy and apicoectomy. Application of gelatin sponge with a dimension of 10 mm × 10 mm × 10 mm led to local hemostasis. Extraction of teeth performed with minimal trauma to the surrounding tissues, the socket margins sutured with 3.0 silk, and sutures removed after 5 days.

Patients were kept under observation for 1 h following the procedure before being sent home. Review appointments were scheduled at 24 h, 5 days. Postoperative antibiotics and analgesics were prescribed for all the patients.

The statistical test was performed by Statistical Package for the Social Sciences (SPSS) version 22 software,(IBM, International) The Chi-square test for association was performed to find if there is any association between the anticoagulants used and bleeding. The P value above will be taken as no association between these two.

Results

There were 54 males and 29 female patients with their age ranging between 30 and 75 [Table 1]. The frequency of medical history is tabulated in Table 2.

Table 1

Gender distribution

Table 2

Medical history and frequency

Table 3 indicates the percentage of patients on various anticoagulants and Table 4 shows the bleeding characteristics of the patients. There were only four incidences of prolonged bleeding in our study.

Table 3

Data of Anticoaglants and Antiplatelets

Table 4

Anti-coagulants *intraoperative bleeding cross tabulation count

It was found that there is no association between the anticoagulant therapy and bleeding during MOS extraction of teeth using Chi-square analysis (P > 0.05) [Table 5].

Table 5

Statistical interpretation

Discussion

The most commonly used drug in anticoagulation therapy is warfarin.[67] Warfarin acts as Vitamin K antagonist and thus decreases the coagulation of blood by inhibiting the enzyme Vitamin K epoxide reductase. Usually, it takes 48–72 h for the anticoagulant effect of warfarin to come into existence in the circulation. Opinion varies among the OMFS regarding the perioperative and postoperative management of patients under warfarin therapy.[89]

The most commonly and frequently used antiplatelet drug is aspirin.[10] Aspiring acts by irreversibly inhibiting the activity of cyclooxygenase-1 and modifying the enzymatic action of cyclooxygenase-2. Another commonly used antiplatelet drug is clopidogrel. It causes irreversible inhibition of adenosine diphosphate receptor, which plays a vital role in promoting platelet aggregation and cross-linking of platelets using fibrins. Other antiplatelet drugs used are ticlopidene, dipyridamole. He also says that bleeding complication is high for patients under combined drug therapy (aspirin and clopidogrel) than single dose therapy.[1112]

In patients with high risk of thromboembolism in whom warfarin therapy has to be ceased for few days, another alternative is sought in order to shorten the period of time that the patient will be not protected from thromboembolism. The alternative is bridging therapy with unfractionated heparin or low-molecular-weight heparin (LMWH).[1314] Bridging therapy is opted because of the side effects that may occur due to the slow reversal of warfarin therapy.

Bridging therapy[13] is commonly used in patients under warfarin therapy when they need to undergo a minor or major oral surgical procedure in order to prevent thromboembolic events and other side effects that can occur due to the cessation of warfarin therapy.[15]

Low-molecular-weight heparin acts by binding itself to antithrombin III and inactivating the factor Xa and factor II. It is commonly used as a bridging therapy in patients under warfarin therapy. Catherine H suggests patients under combination therapy that is, warfarin[16] and LMWH[17] are more prone to the risk of bleeding after extractions.[18]

Most authors[5192021] suggest MOS can be carried out confidently on patients under warfarin therapy or anticoagulation therapy relying on the INR value. Though they all believe on INR ratio, there are different schools of thought.

Ward and Smith[22] suggests that one of the few strategies followed by OMFS during extraction or any MOS is to decrease the INR to 1.5–2.0 instead of completely ceasing the usage of warfarin for few days. This might lead to untoward effect due to the hypercoagulability whereas Bakathir[23] says that if the INR value ≤3.5 in patients under warfarin therapy, MOS can be safely carried out without altering or ceasing the usage of warfarin and without the fear of postoperative bleeding.[242526]

If warfarin efficacy decrease when the INR value falls below two,[27] whereas as Ansell et al.[2829] says that if the patients has serious bleeding, INR should be reduced to 1.0 and in case of urgent surgeries, decrease the INR values to 1–1.5 by three different approaches.[30]

Though the majority of the authors rely on INR, few have differences of opinion.[2829] They believe INR system lack reliability and accuracy when used with thromboplastins with high ISI values and few maxillofacial surgeons rely on PT.[4] Loss of accuracy is due to an error in automated clot detectors used in labs to calculate INR values. Blinder et al.[19] suggests irrespective of INR value, extractions can be carried out in patients under anticoagulation therapy without the fear of postoperative bleeding.[31]

In patients under anticoagulant therapy, local hemostatic agents play an important role in controlling postoperative bleeding effectively. Blinder et al.[2] recommends the use of gelatin sponge and suture for controlling the postoperative bleeding. He also says gelatin sponge plus the suture combination is more effective than gelatin sponge, Fibrin glue and Suture. Occurrence of hemostatic events can be prevented with the usage of local hemostatic agents like oxidized cellulose, gelatine sponge and fibrin glue, whereas in severe hemorrhagic events author suggests cauterization of soft tissue bleeding points by instructing the patient to bite on the gauze for 30 min which will help to control bleeding.[32] Another method[33] used to control postoperative bleeding is administration of HemCon dental dressing or HemCon bandage, HemCon Medical Technologies, Inc. Portland, Oregon, USA. which helps to achieve hemostasis within a minute and also fastens the wound healing. Mechanism behind HemCon dental dressing[34] is, electro positively charged HemCon dressing adheres to the negatively charged red blood cell and thus clot formation occurs immediately within 1 min of the application of the dressing to the surgical site. There is a suggestion[219] that it's better to imply the curettage technique at the site of extraction and then use either tranexamic acid, suture or gelatin sponge to control postoperative bleeding effectively.[3536] Tranexamic acid mouthwash is not as effective as other local hemostatic agents.[37] Using various methods of local hemostatic agents we can observe control of bleeding in the operative site.[38]

Majority of the OMFS recommend continuation of anticoagulant therapy during the minor surgical procedure, and they highly recommend the use of local hemostatic agents.[210] Interruption or cessation of anticoagulation therapy can be dangerous at times and can cost the patient's life due to the high risk of thromboembolic events that can occur. Surgeons should also limit the usage of multi dose antibiotic therapy[39] to patients under warfarin therapy as they can interfere with the anticoagulation effect. Another school of thought[40] says individual approach is the best way to manage the patients under warfarin therapy as the medical conditions vary from patients to patients.