***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: Background —We studied the benefits and risks of adding clopidogrel to different doses of aspirin in the treatment of patients with acute coronary syndrome ( ACS ) . Methods and Results —In the Clopidogrel in Unstable angina to prevent Recurrent Events ( CURE ) trial , 12 562 patients with ACS using aspirin , 75 to 325 mg daily , were r and omized to clopidogrel or placebo for up to 1 year . In this analysis , patients were divided into the following 3 aspirin dose groups : ≤100 mg , 101 through 199 mg , and ≥200 mg . The combined incidence of cardiovascular death , myocardial infa rct ion , or stroke was reduced by clopidogrel regardless of aspirin dose , as follows : ≤100 mg , 10.5 % versus 8.6 % ( relative risk [ RR ] , 0.81 [ 95 % CI , 0.68 to 0.97 ] ) ; 101 to 199 mg , 9.8 % versus 9.5 % ( RR , 0.97 [ 95 % CI 0.77 to 1.22 ] ) ; and ≥200 mg , 13.6 % versus 9.8 % ( RR , 0.71 [ 95 % CI , 0.59 to 0.85 ] ) . The incidence of major bleeding increased with increasing aspirin dose both in the placebo group ( 1.9 % , 2.8 % , and 3.7 % , respectively ; P = 0.0001 ) and the clopidogrel group ( 3.0 % , 3.4 % , and 4.9 % , respectively ; P = 0.0009 ) ; thus , the excess risk with clopidogrel was 1.1 % , 1.2 % , and 1.2 % , respectively . The adjusted hazard ratio for major bleeding for the highest versus the lowest dose of aspirin was 1.9 ( 95 % CI 1.29 to 2.72 ) in the placebo group , 1.6 ( 95 % CI 1.19 to 2.23 ) in the clopidogrel group , and 1.7 ( 95 % CI 1.36 to 2.20 ) in the combined group . Conclusions —In patients with ACS , adding clopidogrel to aspirin is beneficial regardless of aspirin dose . Bleeding risks increase with increasing aspirin dose , with or without clopidogrel , without any increase in efficacy . Our findings suggest that the optimal daily dose of aspirin may be between 75 and 100 mg , with or without clopidogrel In r and omized trials , low-dose ( LD ) and high-dose ( HD ) aspirin ( ASA ) are equally effective in reducing ischemic complications , but HD ASA is associated with an increased risk of bleeding in the setting of dual antiplatelet therapy after percutaneous coronary intervention ( PCI ) . ASA dose after PCI varies across countries , but little is known about variation within the United States ( US ) and whether this variation can be explained by clinical characteristics of patients . We used enrollment data from the Dual Antiplatelet Therapy Study , a r and omized trial design ed to compare 12 versus 30 months of dual antiplatelet therapy after PCI , to quantify the variation in ASA dosing after PCI in the US subjects and assess the extent to which dose variability was attributable to patient characteristics . Of the 23,336 patients enrolled in the US , 28.0 % were prescribed LD ASA  at discharge after PCI . Patient characteristics explained 1.6 % of total variance in ASA dose , whereas the study site accounted for 45.9 % of the unexplained variability . The median odds ratio comparing sites was 5.05 ( 95 % confidence interval 4.29 to 5.85 ) , which was greater than any individual predictor of ASA dose . In conclusion , LD ASA  after PCI in the US was used in a minority of patients , and heterogeneity in its selection was mainly influenced by the site of enrollment rather than patient characteristics . As HD ASA may be associated with adverse events in the setting of dual antiplatelet therapy , reducing local practice variation in the dose of ASA may be a target for quality improvement OBJECTIVES The goal of this study was to determine whether there is a relationship between aspirin dose and the potent antiplatelet agent prasugrel in the TRITON-TIMI 38 ( Trial to Assess Improvement in Therapeutic Outcomes by Optimizing Platelet Inhibition With Prasugrel-Thrombolysis In Myocardial Infa rct ion 38 ) study . BACKGROUND Optimal aspirin dosing after acute coronary syndromes remains uncertain . Previous studies have raised questions regarding an interaction between high-dose aspirin and the potent antiplatelet agent ticagrelor . METHODS In TRITON-TIMI 38 , we classified 12,674 patients into low-dose ( < 150 mg ) or high-dose ( ≥150 mg ) aspirin groups based on discharge dose . We identified independent correlates of dose selection and studied the impact of aspirin dose on the clinical effects of prasugrel . RESULTS There was significant geographical variation in aspirin dosing , with North American patients receiving high-dose aspirin more frequently than other countries ( 66 % vs. 28 % ; p < 0.001 ) . Clinical factors correlating with high-dose aspirin included previous percutaneous coronary intervention and use of aspirin before r and omization . Characteristics associated with the use of low-dose aspirin included age ≥75 years , white race , and use of bivalirudin or a glycoprotein IIb/IIIa inhibitor during coronary intervention . Regardless of low- or high-dose aspirin use , prasugrel had lower rates of the primary efficacy endpoint ( cardiovascular death , myocardial infa rct ion , or stroke [ CVD/MI/stroke ] ) ( hazard ratio [HR]CVD/MI/stroke = 0.78 [ 95 % confidence interval ( CI ) 0.64 to 0.95 ] and HRCVD/MI/stroke = 0.87 [ 95 % CI 0.69 to 1.10 ] , respectively ; p value for interaction = 0.48 ) and higher rates of the primary safety endpoint ( HR TIMI major bleeding = 1.40 [ 95 % CI 0.81 to 2.42 ] and TIMImajor bleeding = 1.30 [ 95 % CI 0.63 to 2.68 ] , respectively ; p value for interaction = 0.84 ) compared with clopidogrel . CONCLUSIONS In TRITON-TIMI 38 , the safety and efficacy outcomes of prasugrel compared with those of clopidogrel were directionally consistent regardless of aspirin dose , although only the primary efficacy endpoint achieved statistical significance . There was no clinical ly meaningful interaction of aspirin with prasugrel , suggesting that previous observations with potent antiplatelet agents indicating differential results are not universal . ( A Comparison of Prasugrel [ CS-747 ] and Clopidogrel in Acute Coronary Syndrome Subjects Who Are to Undergo Percutaneous Coronary Intervention ; NCT00097591 ) 
    Output:
    
Conclusion According to the results of this analysis , a high dose of aspirin following PCI was not associated with any significantly higher rate of CV death/MI/stroke , mortality or MI .
However , MACEs significantly favored a low dose of aspirin .
In addition , TIMI defined minor bleeding was significantly higher with a high dose of aspirin whereas the results for the major bleeding outcomes were not statistically significant .