***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 
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    Input: The PIONEER AF-PCI trial ( Open-Label , R and omized , Controlled , Multicenter Study Exploring Two Treatment Strategies of Rivaroxaban and a Dose-Adjusted Oral Vitamin K Antagonist Treatment Strategy in Subjects with AF who Undergo Percutaneous Coronary Intervention ) is an ambitious , open-label comparison of 3 regimens , almost exclusively in Caucasians , all of whom had coexisting atrial fibrillation and atherosclerotic coronary artery disease requiring stenting ( PCI-S ) . These 2 conditions when they coexist pose a clinical challenge , necessitating concurrent usage of dual antiplatelet and anticoagulation therapy , a cocktail which presents major bleeding risks . Because anticoagulation therapy is suboptimal in preventing stent thrombosis and dual anti platelet therapy is inadequate in averting embolic stroke in atrial fibrillation , neither treatment is sufficient and they must be combined . The study has a unique design and consists of 2 treatment arms and a control ( see Figure 1 for trial design ) , each with about 700 patients and a 20 % dropout rate in groups 1 and 2 but a statistically greater rate of 29 % in group 3 . Both treatment arms are modeled upon previous studies , which involved patients with the need for both antiplatelet therapy and anticoagulation ( see Figure 2 for derivation of trial from WOEST and ATLAS-TIMI 51 ) . The control arm , design ated group 3 in the trial , consists of the US st and ard of practice regimen , in this situation , called “ triple therapy , ” consisting of aspirin 100 mg/d , clopidogrel 75 mg/d , and warfarin maintaining the INR between 2 and 3 . About 7 % of patients in groups 1 and 2 received a different P2Y12 inhibitor , either prasugrel or ticagrelor , and about 4 % in group 3 . Prominent among the numerous exclusions were patients with a previous stroke and a creatinine clearance of under 30 mL/min . In arm 1 , patients with a creatinine clearance between 30 and 60 mL/min received a lower dose of 10 mg of rivaroxaban . The first treatment arm , called arm 1 , is a reprisal of the treatment arm of the Belgian 2013 WOEST trial which showed that clopidogrel 75 mg and warfarin , maintaining an INR of 2 to 3 , were associated with less combined TIMI major and minor bleeding as well as no increase in cardiac or neurological thrombotic complications when compared to the same control arm as is in this study . Despite having studied only 573 patients for just a year , WOEST was influential in generating the recommendation ( level B ) from the European Society of Cardiology to use this regimen in some people at high risk for bleeding with stents who also require anticoagulation . Furthermore in PIONEER , arm 1 , rivaroxaban 15 mg has been substituted for warfarin ; otherwise , the other trial drugs are identical to those in WOEST . A compelling question posed by this arm of the study , although not the primary end point of the study , is whether equivalent stent patency or prevention of atherosclerotic or thromboembolic complications can be achieved with only a single antiplatelet drug throughout the entire 12 months of treatment , including the vital first month poststent . Also addressed is whether the WOEST results can be replicated substituting rivaroxaban , a drug that offers several advantages over warfarin . In treatment group 1 , one would intuitively expect confirmation of the bleeding advantage observed in WOEST , since it contains 2 drugs versus the 3 in the control group , and therefore would be expected to be associated with less bleeding in group 1 versus group 3 . The second treatment group is based on the 2012 ATLAS ACS 2-TIMI 51 trial and consists of very-low-dose rivaroxaban 2.5 mg twice a day along with clopidogrel 75 mg/d and aspirin 100 mg/d . An interesting point of arm 2 versus 3 , although again not the primary end point , is if a dosage of rivaroxaban , which is only 25 % of the FDA -approved dose of that needed to treat atrial fibrillation , would be adequate in preventing embolic strokes . One would anticipate in group 2 that the dual antiplatelet therapy would be equally effective in preventing stent occlusion and recurrent coronary events as the BACKGROUND Patients receiving oral anticoagulation ( OAC ) who undergo drug-eluting stent ( DES ) implantation require additional dual antiplatelet therapy with aspirin and clopidogrel . Such triple therapy confers an elevated bleeding risk , and its optimal duration is not known . OBJECTIVES The goal of this study was to evaluate whether shortening the duration of clopidogrel therapy from 6 months to 6 weeks after DES implantation was associated with a superior net clinical outcome in patients receiving concomitant aspirin and OAC .  METHODS In this r and omized , open-label trial , we enrolled patients receiving OAC who underwent DES implantation at 3 European centers between September 2008 and December 2013 . A total of 614 patients receiving concomitant aspirin and OAC  were r and omized to either 6-week clopidogrel therapy ( n=307 ) or 6-month clopidogrel therapy ( n=307 ) . The primary endpoint was a composite of death , myocardial infa rct ion ( MI ) , definite stent thrombosis , stroke , or Thrombolysis In Myocardial Infa rct ion ( TIMI ) major bleeding at 9 months . RESULTS The primary endpoint occurred in 30 patients ( 9.8 % ) in the 6-week group compared with 27 patients ( 8.8 % ) in the 6-month group ( hazard ratio [ HR ] : 1.14 ; 95 % CI : 0.68 to 1.91 ; p=0.63 ) . There were no significant differences for the secondary combined ischemic endpoint of cardiac death , MI , definite stent thrombosis , and ischemic stroke ( 12 [ 4.0 % ] vs. 13 [ 4.3 % ] ; HR : 0.93 ; 95 % CI : 0.43 to 2.05 ; p=0.87 ) or the secondary bleeding endpoint of TIMI major bleeding ( 16 [ 5.3 % ] vs. 12 [ 4.0 % ] ; HR : 1.35 ; 95 % CI : 0.64 to 2.84 ; p=0.44 ) . CONCLUSIONS Six weeks of triple therapy was not superior to 6 months with respect to net clinical outcomes . These results suggest that physicians should weigh the trade-off between ischemic and bleeding risk when choosing the shorter or longer duration of triple therapy . ( Triple Therapy in Patients on Oral Anticoagulation After Drug Eluting Stent Implantation [ ISAR-TRIPLE ] ; NCT00776633 ) Background Triple antithrombotic therapy with warfarin plus two antiplatelet agents is the st and ard of care after percutaneous coronary intervention ( PCI ) for patients with atrial fibrillation , but this therapy is associated with a high risk of bleeding . Methods In this multicenter trial , we r and omly assigned 2725 patients with atrial fibrillation who had undergone PCI to triple therapy with warfarin plus a P2Y12 inhibitor ( clopidogrel or ticagrelor ) and aspirin ( for 1 to 3 months ) ( triple‐therapy group ) or dual therapy with dabigatran ( 110 mg or 150 mg twice daily ) plus a P2Y12 inhibitor ( clopidogrel or ticagrelor ) and no aspirin ( 110‐mg and 150‐mg dual‐therapy groups ) . Outside the United States , elderly patients ( ≥80 years of age ; ≥70 years of age in Japan ) were r and omly assigned to the 110‐mg dual‐therapy group or the triple‐therapy group . The primary end point was a major or clinical ly relevant nonmajor bleeding event during follow‐up ( mean follow‐up , 14 months ) . The trial also tested for the noninferiority of dual therapy with dabigatran ( both doses combined ) to triple therapy with warfarin with respect to the incidence of a composite efficacy end point of thromboembolic events ( myocardial infa rct ion , stroke , or systemic embolism ) , death , or unplanned revascularization . Results The incidence of the primary end point was 15.4 % in the 110‐mg dual‐therapy group as compared with 26.9 % in the triple‐therapy group ( hazard ratio , 0.52 ; 95 % confidence interval [ CI ] , 0.42 to 0.63 ; P<0.001 for noninferiority ; P<0.001 for superiority ) and 20.2 % in the 150‐mg dual‐therapy group as compared with 25.7 % in the corresponding triple‐therapy group , which did not include elderly patients outside the United States ( hazard ratio , 0.72 ; 95 % CI , 0.58 to 0.88 ; P<0.001 for noninferiority ) . The incidence of the composite efficacy end point was 13.7 % in the two dual‐therapy groups combined as compared with 13.4 % in the triple‐therapy group ( hazard ratio , 1.04 ; 95 % CI , 0.84 to 1.29 ; P=0.005 for noninferiority ) . The rate of serious adverse events did not differ significantly among the groups . Conclusions Among patients with atrial fibrillation who had undergone PCI  , the risk of bleeding was lower among those who received dual therapy with dabigatran and a P2Y12 inhibitor than among those who received triple therapy with warfarin , a P2Y12 inhibitor , and aspirin . Dual therapy was noninferior to triple therapy with respect to the risk of thromboembolic events . ( Funded by Boehringer Ingelheim ; RE‐DUAL PCI Clinical Trials.gov number , NCT02164864 . OBJECTIVES Optimal antithrombotic/anticoagulation therapy in patients on chronic oral anticoagulation ( OAC ) undergoing drug-eluting stent ( DES ) implantation is unknown . We investigated the efficacy and safety of two regimens of antithrombotic/anticoagulation therapy in patients who present for DES implantation whilst on OAC . METHODS We included a series of 515 patients on OAC who underwent DES implantation between 2002 and 2007 . Based on predefined clinical and echocardiographic criteria , 306 patients continued OAC ( triple therapy )  and 209 patients discontinued OAC ( dual therapy ) for the time they received antiplatelet therapy with clopidogrel and aspirin [ stent-related antithrombotic treatment ( SRAT ) ] . The primary end point was a composite of death , myocardial infa rct ion , stent thrombosis or stroke . RESULTS During SRAT the primary endpoint was observed in 13 patients in the group with triple therapy versus 15 patients in the group with dual therapy [ Kaplan-Meier estimates 4.2 % and 7.2 % , odds ratio ( OR ) = 0.61 , 95 % confidence interval ( CI ) 0.29 - 1.28 ; P = 0.19 ] . At 2 years of follow-up , the primary endpoint was observed in 35 patients in the group with triple therapy versus 36 patients in the group with dual therapy ( Kaplan-Meier estimates 14.1 % and 18.0 % , OR = 0.76 , 95 % CI : 0.48 - 1.21 ; P = 0.25 ) . Two-year incidence of major bleeding was 1.4 % ( n = 4 , triple therapy ) versus 3.1 % ( n = 6 , dual therapy ) ( P = 0.34 ) . CONCLUSIONS In patients on chronic OAC undergoing DES implantation , clinical and echocardiographic criteria help to define postprocedural antithrombotic/anticoagulation therapy . Based on these criteria , both a double antiplatelet therapy ( clopidogrel plus aspirin ) and a triple therapy ( OAC plus clopidogrel plus aspirin ) are associated with favourable safety and efficacy Most evidence regarding the efficacy and safety of the antithrombotic regimens for patients with atrial fibrillation ( AF ) undergoing percutaneous coronary intervention with stent ( PCI‐S )  derives from small , single‐center , retrospective data sets . To obtain further data on this issue , we carried out the prospect i ve , multicenter , observational Management of patients with Atrial Fibrillation undergoing Coronary Artery Stenting ( AFCAS ) registry ( Clinical trials.gov identifier NCT00596570 ) BACKGROUND If percutaneous coronary intervention ( PCI ) is required in patients taking oral anticoagulants , antiplatelet therapy with aspirin and clopidogrel is indicated , but such triple therapy increases the risk of serious bleeding . We investigated the safety and efficacy of clopidogrel alone compared with clopidogrel plus aspirin . METHODS We did an open-label , multicentre , r and omised , controlled trial in 15 centres in Belgium and the 
    Output:
    
No significant differences of coronary events were found .