***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: The optimal duration of treatment with clopidogrel after percutaneous coronary intervention ( PCI ) with stent placement remains controversial . The R and omized Argentine Clopidogrel Stent ( RACS ) trial was a prospect i ve , r and omized , nonblinded study of 1,004 patients undergoing PCI who were r and omized after successful bare metal stent placement to 30 versus 180 days of clopidogrel ; all patients also received aspirin . Patients were eligible regardless of whether they had presented with ST-elevation myocardial infa rct ion ( MI ) , acute coronary syndrome , or stable angina . The primary end point was a composite of death , MI , and stroke at 180 days . Baseline clinical characteristics showed no differences between groups in terms of age , gender , history , risk factors , or incidence of diabetes ; 72 % presented with an acute coronary syndrome and 15 % had MI as the indication for PCI . At hospital discharge and 30 days , when the 2 groups received the same treatment , there were no significant differences between groups in frequency of death , MI , or stroke . However , from 30 days to 6 months , patients assigned to 6 months of clopidogrel reached the primary end point of death , MI , and stroke less frequently ( 4.99 % vs 1.74 % , p = 0.010 , relative risk decrease 65 % ) . No significant between-group differences were found in frequency of total bleeding ( 0.64 % vs 1.52 % , p = 0.34 ) for the control and study groups . In conclusion , after successful placement of a bare metal stent in a coronary artery , patients treated with 6 months of clopidogrel showed a trend toward fewer adverse events compared with those treated for 30 days Background — The optimal duration of dual-antiplatelet therapy and the risk-benefit ratio for long-term dual-antiplatelet therapy after coronary stenting remain poorly defined . We evaluated the impact of up to 6 versus 24 months of dual-antiplatelet therapy in a broad all-comers patient population receiving a balanced proportion of Food and Drug Administration – approved drug-eluting or bare-metal stents . Methods and Results — We r and omly assigned 2013 patients to receive bare-metal , zotarolimus-eluting , paclitaxel-eluting , or everolimus-eluting stent implantation . At 30 days , patients in each stent group were r and omly allocated to receive up to 6 or 24 months of clopidogrel therapy in addition to aspirin . The primary end point was a composite of death of any cause , myocardial infa rct ion , or cerebrovascular accident . The cumulative risk of the primary outcome at 2 years was 10.1 % with 24-month dual-antiplatelet therapy compared with 10.0 % with 6-month dual-antiplatelet therapy ( hazard ratio , 0.98 ; 95 % confidence interval , 0.74–1.29 ; P=0.91 ) . The individual risks of death , myocardial infa rct ion , cerebrovascular accident , or stent thrombosis did not differ between the study groups ; however , there was a consistently greater risk of hemorrhage in the 24-month clopidogrel group according to all prespecified bleeding definitions , including the recently proposed Bleeding Academic Research Consortium classification . Conclusions — A regimen of 24 months of clopidogrel therapy in patients who had received a balanced mixture of drug-eluting or bare-metal stents was not significantly more effective than a 6-month clopidogrel regimen in reducing the composite of death due to any cause , myocardial infa rct ion , or cerebrovascular accident . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00611286 Background Dual antiplatelet therapy with aspirin and thienopyridine is required after placement of coronary drug-eluting stents ( DES ) to prevent thrombotic complications . Current clinical guidelines recommend at least 6 to 12 months of treatment after a DES implantation , but it may be beneficial to apply dual antiplatelet therapy for a longer duration . Methods / design The optimal dual antiplatelet therapy ( OPTIDUAL ) study aims to compare the benefits and risks of dual antiplatelet therapy applied for either 12 or 48 months . We will examine the occurrence of major adverse cardiovascular and cerebrovascular events ( MACCE ) in patients undergoing percutaneous coronary intervention with DES for the treatment of coronary lesions . The OPTIDUAL study is an open-label multicenter , r and omized , national trial that will include 1,966 patients treated with DES . All patients will be treated with dual antiplatelet therapy for 12 months ( + /− 3 ) . Then , patients with no MACCE or major bleeding will be r and omized to receive either 36 additional months of clopidogrel plus aspirin or aspirin only . The primary end-point is the combination of death from all causes , myocardial infa rct ion , stroke and major bleeding . The secondary end points include the individual components of the primary end-point , stent thrombosis , repeat revascularization of the treated vessel and minor bleeding . Discussion This r and omized trial is design ed to assess the benefits and safety of 12 versus 48 months of dual antiplatelet therapy in patients that receive a DES . We aim to determine whether substantial prolongation of clopidogrel ( a thienopyridine ) after DES implantation offers an advantage over its discontinuation . Trial registration Clinical Trials.gov Identifier : OBJECTIVES The goal of this study was to evaluate shorter duration ( 3 months ) dual antiplatelet therapy ( DAPT ) after  drug-eluting stent ( DES ) implantation .  BACKGROUND There have been few published reports of prospect i ve r and omized clinical studies comparing the safety and efficacy of shorter duration DAPT after DES implantation . METHODS We r and omly assigned 2,117 patients with coronary artery stenosis into 2 groups according to DAPT duration and stent type : 3-month DAPT following Endeavor zotarolimus-eluting stent ( E-ZES ) implantation ( E-ZES+3-month DAPT , n=1,059 ) versus 12-month DAPT following the other DES implantation ( st and ard therapy , n=1,058 ) . We hypothesized that the E-ZES+3-month DAPT would be noninferior to the st and ard therapy for the primary composite endpoint ( cardiovascular death , myocardial infa rct ion , stent thrombosis , target\vessel revascularization , or bleeding ) at 1 year . RESULTS The primary endpoint occurred in 40 ( 4.7 % ) patients assigned to E-ZES+3-month DAPT compared with 41 ( 4.7 % ) patients assigned to the st and ard therapy ( difference : 0.0 % ; 95 % confidence interval [ CI ] : -2.5 to 2.5 ; p=0.84 ; p<0.001 for noninferiority ) . The composite rates of any death , myocardial infa rct ion , or stent thrombosis were 0.8 % and 1.3 % , respectively ( difference : -0.5 % ; 95 % CI : -1.5 to 0.5 ; p=0.48 ) . The rates of stent thrombosis were 0.2 % and 0.3 % , respectively ( difference : -0.1 % ; 95 % CI : -0.5 to 0.3 ; p=0.65 ) without its further occurrence after cessation of clopidogrel in the E-ZES+3-month DAPT group . The rates of target vessel revascularization were 3.9 % and 3.7 % , respectively ( difference : 0.2 % ; 95 % CI : -2.3 to 2.6 ; p=0.70 ) . CONCLUSIONS E-ZES+3-month DAPT was noninferior to the st and ard therapy with respect to the occurrence of the primary endpoint . ( REal Safety and Efficacy of a 3-month dual antiplatelet Therapy following E-ZES implantation [ RESET ] ; NCT01145079 ) Background — The need for prolonged aspirin and thienopyridine therapy and the risk of stent thrombosis ( ST ) remain as drawbacks associated with drug-eluting stents . Methods and Results — A prospect i ve observational cohort study was conducted between June 2002 and January 2004 on 3021 patients consecutively and successfully treated in 5389 lesions with drug-eluting stents . Detailed patient information was collected on antiplatelet therapy . We analyzed the incidence of ST throughout the 18-month follow-up period and its relationship with thienopyridine therapy .  ST occurred in 58 patients ( 1.9 % ) at 18 months . Forty-two patients ( 1.4 % ) experienced the event within 6 months of stent implantation . Acute myocardial infa rct ion ( fatal or nonfatal ) occurred in 46 patients ( 79 % ) and death in 23 patients ( 39 % ) with ST . The median interval from discontinuation of thienopyridine therapy to ST was 13.5 days ( interquartile range 5.2 to 25.7 days ) for the first 6 months and 90 days ( interquartile range 30 to 365 days ) between 6 and 18 months . On multivariable analysis , the strongest predictor for ST within 6 months of stenting was discontinuation of thienopyridine therapy ( hazard ratio , 13.74 ; 95 % CI , 4.04 to 46.68 ; P<0.001 ) . Thienopyridine discontinuation after 6 months did not predict the occurrence of ST ( hazard ratio , 0.94 ; 95 % CI , 0.30 to 2.98 ; P=0.92 ) . Conclusions — Discontinuation of thienopyridine therapy was the major determinant of ST within the first 6 months , but insufficient information is available to determine whether there is benefit in continuing a thienopyridine beyond 6 months CONTEXT Following percutaneous coronary intervention ( PCI ) , short-term clopidogrel therapy in addition to aspirin leads to greater protection from thrombotic complications than aspirin alone . However , the optimal duration of combination oral antiplatelet therapy is unknown . Also , although current clinical data suggest a benefit for beginning therapy with a clopidogrel loading dose prior to PCI , the practical application of this therapy has not been prospect ively studied . OBJECTIVES To evaluate the benefit of long-term ( 12-month ) treatment with clopidogrel after PCI and to determine the benefit of initiating clopidogrel with a preprocedure loading dose , both in addition to aspirin therapy . DESIGN , SETTING , AND PARTICIPANTS The Clopidogrel for the Reduction of Events During Observation ( CREDO ) trial , a r and omized , double-blind , placebo-controlled trial conducted among 2116 patients who were to undergo elective PCI or were deemed at high likelihood of undergoing PCI , enrolled at 99 centers in North America from June 1999 through April 2001 . INTERVENTIONS Patients were r and omly assigned to receive a 300-mg clopidogrel loading dose ( n = 1053 ) or placebo ( n = 1063 ) 3 to 24 hours before PCI . Thereafter , all patients received clopidogrel , 75 mg/d , through day 28 . From day 29 through 12 months , patients in the loading-dose group received clopidogrel , 75 mg/d , and those in the control group received placebo . Both groups received aspirin throughout the study . MAIN OUTCOME MEASURES One-year incidence of the composite of death , myocardial infa rct ion ( MI ) , or stroke in the intent-to-treat population ; 28-day incidence of the composite of death , MI , or urgent target vessel revascularization in the per- protocol population . RESULTS At 1 year , long-term clopidogrel therapy was associated with a 26.9 % relative reduction in the combined risk of death , MI , or stroke ( 95 % confidence interval [ CI ] , 3.9%-44.4 % ; P = .02 ; absolute reduction , 3 % ) . Clopidogrel pretreatment did not significantly reduce the combined risk of death , MI , or urgent target vessel revascularization at 28 days ( reduction , 18.5 % ; 95 % CI , -14.2 % to 41.8 % ; P = .23 ) . However , in a prespecified subgroup analysis , patients who received clopidogrel at least 6 hours before PCI experienced a relative risk reduction of 38.6 % ( 95 % CI , -1.6 % to 62.9 % ; P = .051 ) for this end point compared with no reduction with treatment less than 6 hours before PCI . Risk of major bleeding at 1 year increased , but not significantly ( 8.8 % with clopidogrel vs 6.7 % with placebo ; P = .07 ) . CONCLUSIONS Following PCI , long-term ( 1-year ) clopidogrel therapy significantly reduced the risk of adverse ischemic events . A loading dose of clopidogrel given at least 3 hours before the procedure did not reduce events at 28 days , but subgroup analyses suggest that longer intervals between the loading dose and PCI may reduce events BACKGROUND The potential benefits and risks of the 
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Subgroup analysis based on age , prior diabetes , and prior ACS failed to show any group where longer duration s were consistently better than shorter ones .
There are no cardiovascular or mortality benefits associated with extended duration of DAPT , but the risk of major bleeding was significantly lower with shorter lengths of therapy