***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Introduction Oral anticoagulants are widely prescribed drugs . Interruption of anticoagulant therapy prior to oral surgery has been an issue of great controversy . The purpose of this study was to evaluate the incidence of bleeding complications after dental extraction s in patients on anticoagulant therapy ( warfarin ) in whom different local hemostatic methods were used . Material and methods Patients using warfarin and requiring extraction s of at least two teeth were screened to participate in this prospect i ve , r and omized study . Extraction sites were considered as sampling units ( statistically representative sample size ) and were allocated to one of the three study groups ( G1—4.8 % tranexamic acid ; G2—fibrin sponge ; and G3—no local hemostatic agents ) . Results Eighty-four extraction sites were obtained from patients with mitral valve prolapse ( 47.4 % ) , prosthetic cardiac valve ( 23.7 % ) , venous thromboembolism ( 21.1 % ) , and pulmonary embolism ( 5.2 % ) .  International normalized ratio ( INR ) values ranged between 2.1 and 3.1 ( mean 2.51 ± 0.1 ) . Postoperative bleeding was observed in four surgical sites ( p < 0.001 ) and was mainly in older patients ( p = 0.005 ) . Discussion The three local hemostatic protocol s were similarly effective in controlling postoperative bleeding in patients undergoing anticoagulant therapy with warfarin .  The majority of teeth could be extracted with minimal problems in patients with cardiovascular diseases receiving treatment with anticoagulant therapy The optimal procedure for withdrawal of warfarin in patients with deep vein thrombosis ( DVT ) is still not defined . Rebound thrombin generation , which occurs after the withdrawal of warfarin , has been said to be associated with early recurrence of DVT . The aim of this study was to compare two procedures for warfarin withdrawal after the first episode of DVT with respect to rebound thrombin generation .  Forty-one consecutive patients were r and omly assigned to abrupt withdrawal of warfarin ( group A ) , or to an additional month of warfarin , at the fixed dose of 1.25 mg/day ( group B ) . Plasma sample s were withdrawn for the assay of prothrombin fragment F1 + 2 ( F1 + 2 ) , protein C , factor VII and International Normalized Ratio ( INR ) , before any anticoagulant treatment ( I ) , during initial heparin ( II ) and full dose warfarin ( III ) , at the end of full dose warfarin ( IV ) and then 1 ( V ) , 4 ( VI ) , 5 ( VII ) and 9 ( VIII ) weeks after r and omization . The mean duration of full-dose warfarin treatment , the mean warfarin dose and the mean INR during full-dose warfarin  treatment were similar in the two groups . A decrease in F1 + 2 was observed during heparin and warfarin treatment ( II , 1.7 nmol/ml ; III , 1.0 nmol/ml ; IV , 0.7 nmol/ml ; versus I , 3.5 nmol/ml ; P<0.01 ) . After the withdrawal of warfarin , an increase in F1 + 2 was observed in both groups , but without significant statistical differences ( group A : V , 1.2 nmol/ml ; VI , 1.5 nmol/ml ; VII , 1.6 nmol/ml ; VIII , 1.1 nmol/ml ; group B : V , 1.3 nmol/ml ; IV , 1.5 nmol/ml ; VII , 1.4 nmol/ml ; VIII , 1.4 nmol/ml ) . No significant difference between the two groups was observed in the recovery of protein C and factor VII . Four patients experienced a recurrence of DVT , three in group B and one in group A. Our findings confirm that rebound thrombin generation occurs in patients with DVT after the withdrawal of warfarin .  Rebound thrombin generation is not reduced by a low , fixed dose of warfarin In a double-blind trial tranexamic acid ( AMCA , Cyclokapron ) , 1 g three times a day for five days , significantly reduced blood loss and transfusion requirements after dental extraction in patients with haemophilia and Christmas disease . No side effects were seen in either group of patients . Screening tests showed no toxic action of tranexamic acid on the liver , kidney , or heart A total of 124 patients on oral anticoagulation therapy with coumarin were treated by orosurgical procedures and entered into a study to determine the hemostatic efficiency of different methods . The therapeutic anticoagulation level was determined in accordance with the recommendations of the American Heart Association ( low risk : 2.0 < INR < 3.0 ; high risk : 2.5 < INR < 3.5 ) and maintained during treatment . In one group , the alveoli were treated with collagen , in a second group a mouthrinse regime with tranexamic acid was implemented . Twenty-three patients had to be excluded because  anticoagulation levels differed from the recommended values . The group treated with collagen included 31 patients , the group with tranexamic acid mouthwashes , 32 patients . A third group was analyzed in which a controlled change in the anticoagulation level had been performed and all treated alveoli had been covered by mucosal flaps ( n = 38 ) ; they were compared to the other two groups . The surgical proceedings were outlined precisely . Patients treated with collagen had a bleeding rate of 19 % , patients with tranexamic acid mouthwash 6 % , and those treated with mucosal flaps 40 % . The data were not suited for statistical evaluation , they were objected to a descriptive analysis : the confidence intervals were determined by tables for binomial distributions . These did confirm the difference in the frequency of bleeding for the tranexamic acid and mucosal flap groups We carried out a placebo-controlled , double-blind , r and omized study of the hemostatic effect of tranexamic acid mouthwash after oral surgery in 39 patients receiving anticoagulant agents because of the presence of cardiac valvular stenosis , a prosthetic cardiac valve , or a vascular prosthesis . Surgery was performed with no change in the level of anticoagulant therapy , and treatment with the anticoagulant agent was continued after surgery . Before it was sutured , the operative field was irrigated in 19 patients with 10 ml of a 4.8 percent aqueous solution of tranexamic acid ( an inhibitor of fibrinolysis ) and in 20 patients with a placebo solution . For seven days thereafter , patients were instructed to rinse their mouths with 10 ml of the assigned solution for two minutes four times a day . There were no significant differences between the two treatment groups in base-line variables , including the level of anticoagulation at the time of surgery . Eight patients in the placebo group had a total of 10 postoperative bleeding episodes , whereas only 1 patient in the tranexamic acid group had a bleeding episode ( P = 0.01 ) . There were no systemic side effects . We conclude that local antifibrinolytic therapy is effective in preventing bleeding after oral surgery in patients who are being treated with anticoagulants PURPOSE This study assessed the risk associated with several schedules of perioperative treatment with coumadin in anticoagulated patients who underwent oral surgery . PATIENTS AND METHODS A prospect i ve , r and omized study compared bleeding complications with six perioperative schedules in 92 patients chronically treated with acenocoumarol .  In three of the perioperative schedules , the dose was reduced before surgery and calcium heparin was added . In the other three , oral anticoagulation was not modified and heparin was not used . The groups also differed regarding the antifibrinolytic agents used and the postoperative measures applied . RESULTS Those schedules in which the oral anticoagulation was not modified preoperatively and an antifibrinolytic agent was applied locally both during and after surgery were not associated with a significantly higher odds ratio of bleeding complications than those in whom oral anticoagulation was reduced and calcium heparin was added preoperatively . CONCLUSIONS In orally anticoagulated patients who undergo oral surgery , schedules that maintain the oral anticoagulant regimen and use local tranexamic acid as an antifibrinolytic agent postoperatively for 2 days are safe , simple , and less troublesome The hemostatic effect of tranexamic acid solution ( 4.8 % ) used as a mouthwash was compared with a placebo solution in 93 patients on continuous , unchanged , oral anticoagulant treatment undergoing oral surgery . The investigation was a r and omized , double-blind , placebo-controlled , multicenter study . Before suturing , the surgically treated region was irrigated with 10 mL of tranexamic acid ( 46 patients )  or placebo ( 47 patients ) solution . The patients then performed mouthwash with 10 mL of the solution for 2 minutes four times daily for 7 days . The treatment groups were comparable regarding age , smoking habits , and surgery . Laboratory variables measuring vitamin K-dependent coagulation factors were within therapeutic ranges ( international normalized ratio 4.00 to 2.10 ) . One of the clinics used a different method for these measurements and therefore the levels of coagulation factor X in plasma obtained for the three clinics were compared . No significant difference in the range at which surgery was performed was found between clinics . In the placebo group , 10 patients developed bleeding requiring treatment , while none of the patients treated with tranexamic acid solution had bleeding . This difference was statistically significant ( P < .01 ) . The treatment with mouthwash was well tolerated . It was concluded that patients on oral anticoagulants  can undergo oral surgery within the therapeutic range without reducing the dosage of anticoagulants , provided that local antifibrinolytic treatment with tranexamic acid solution is instituted PURPOSE The aim of this prospect i ve study was to compare the effectiveness of a 4.8 % tranexamic acid mouthwash versus an autologous fibrin glue preparation to control hemostasis in patients therapeutically anticoagulated with warfarin who required dental extraction s without interruption of their treatment . PATIENTS AND METHODS The 49 patients who underwent 152 dental extraction s were r and omly allocated to 2 groups : Group A were required to rinse with 10 mL of a 4.8 % tranexamic acid solution 4 times a day for 7 days postoperatively . Group B received autologous fibrin glue intraoperatively . The international normalized ratio was measured on the day of the procedure . All procedures were performed on an ambulatory basis by the same surgeon . RESULTS Of the 49 patients , 2 presented with postoperative bleeding ( 4 % ) . Both patients were from the autologous fibrin glue group and were found to have grossly elevated international normalized ratios on the day of the bleeding that was unaccounted for . CONCLUSIONS This study supports the consensus that dental extraction s can be performed without modification of oral anticoagulant treatment . Local hemostasis with an absorbable oxidized cellulose mesh , tranexamic acid , and sutures is the more cost efficient of the 2 methods compared ; however , autologous fibrin glue has an important role in patients unable to use a mouthwash effectively A double-blind r and omized study was carried out to evaluate the clinical hemostatic effect of tranexamic acid mouthwash after dental extraction in 30 patients who received anticoagulant agents .  Surgery was performed with a reduction in the level of anticoagulant therapy in the control group and with no change in the level of anticoagulant therapy in the group who received the tranexamic acid . After the extraction the surgical field was irrigated with a 5 % solution of tranexamic acid in the group of 15 patients whose anticoagulant treatment had not been discontinued and with a placebo solution in the group of 15 patients for whom the anticoagulant therapy was reduced . Patients were instructed to rinse their mouths with 10 ml of the assigned solution for 2 minutes four times a day for 7 days . There was no significant difference between the two treatment groups in the bleeding incidence after oral surgery . We conclude that the anticoagulant treatment does not need to be withdrawn before oral surgery provided that local antifibrinolytic therapy is instituted 
    Output:
    
Therefore , a beneficial effect of antifibrinolytic therapy can currently only be assumed based on data from the people using VKAs