***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: CONTEXT Of the 200 million adults worldwide who undergo noncardiac surgery each year , more than 1 million will die within 30 days . OBJECTIVE To determine the relationship between the peak fourth-generation troponin T ( TnT ) measurement in the first 3 days after noncardiac surgery and 30-day mortality . DESIGN , SETTING , AND PARTICIPANTS A prospect i ve , international cohort study that enrolled patients from August 6 , 2007 , to January 11 , 2011 . Eligible patients were aged 45 years and older and required at least an overnight hospital admission after having noncardiac surgery . MAIN OUTCOME MEASURES Patients ' TnT levels were measured 6 to 12 hours after surgery and on days 1 , 2 , and 3 after surgery . We undertook Cox regression analysis in which the dependent variable was mortality until 30 days after surgery , and the independent variables included 24 preoperative variables . We repeated this analysis , adding the peak TnT measurement during the first 3 postoperative days as an independent variable and used a minimum P value approach to determine if there were TnT thresholds that independently altered patients ' risk of death . RESULTS A total of 15,133 patients were included in this study . The 30-day mortality rate was 1.9 % ( 95 % CI , 1.7%-2.1 % ) . Multivariable analysis demonstrated that peak TnT values of at least 0.02 ng/mL , occurring in 11.6 % of patients , were associated with higher 30-day mortality compared with the reference group ( peak TnT ≤ 0.01 ng/mL ) : peak TnT of 0.02 ng/mL ( adjusted hazard ratio [ aHR ] , 2.41 ; 95 % CI , 1.33 - 3.77 ) ; 0.03 to 0.29 ng/mL ( aHR , 5.00 ; 95 % CI , 3.72 - 6.76 ) ; and 0.30 ng/mL or greater ( aHR , 10.48 ; 95 % CI , 6.25 - 16.62 ) . Patients with a peak TnT value of 0.01 ng/mL or less , 0.02 , 0.03 - 0.29 , and 0.30 or greater had 30-day mortality rates of 1.0 % , 4.0 % , 9.3 % , and 16.9 % , respectively . Peak TnT measurement added incremental prognostic value to discriminate those likely to die within 30 days for the model with peak TnT measurement vs without ( C index = 0.85 vs 0.81 ; difference , 0.4 ; 95 % CI , 0.2 - 0.5 ; P < .001 for difference between C index values ) . The net reclassification improvement with TnT was 25.0 % ( P < .001 ) . CONCLUSION Among patients undergoing noncardiac surgery , the peak postoperative TnT measurement during the first 3 days after surgery was significantly associated with 30-day mortality This study considered if N-terminal prohormone brain natriuretic peptide ( NT-proBNP ) is associated with increased risk for postoperative cardiac events in high-risk patients undergoing noncardiac surgery .  In addition , this report describes how levels of NT-proBNP are affected by noncardiac surgery . The study design was a prospect i ve cohort study that enrolled 83 patients age > or = 50 years with > or = 1 risk factor for coronary artery disease having intermediate or high-risk noncardiac surgery .  NT-proBNP levels  were measured preoperatively and on postoperative days 1 and 3 . During the month following surgery , 25 patients ( 33 % ) had a combined 37 postoperative cardiac events including 15 episodes of heart failure ( 20 % ) , 12 episodes of new dysrhythmia ( 16 % ) , 7 myocardial infa rct ions ( 9 % ) , and 3 cardiac arrests ( 4 % ) . Preoperative NT-proBNP level > or = 457 pg/ml was significantly associated with occurrence of a postoperative cardiac event ( odds ratio 10.5 , 95 % confidence interval 1.9 to 56.6 , p = 0.006 ) . After surgery , 64 of 72 patients ( 89 % ) had an increase in NT-proBNP from their preoperative level . In conclusion , this study determined there was a significant association between elevated preoperative NT-proBNP and occurrence of a postoperative cardiac event . In addition , increased NT-proBNP after noncardiac surgery is not uncommon even in the absence of clinical ly identifiable heart failure Background — Postoperative atrial fibrillation  ( AF ) is a complication of thoracic surgery for lung cancer , with a reported incidence that can run as high as 42 % . Recently , it has been observed retrospectively that B-type natriuretic peptide predicts AF after cardiac surgery . We performed a prospect i ve study to evaluate the role of N-terminal pro-B-type natriuretic peptide ( NT-proBNP ) as a marker for risk stratification of postoperative AF in patients undergoing thoracic surgery for lung cancer . Methods and Results — We measured NT-proBNP levels in 400 patients ( mean age , 62±10 years ; 271 men ) 24 hours before and 1 hour after surgery . The primary end point of the study was the incidence of postoperative AF . Overall , postoperative AF occurred in 72 patients ( 18 % ) . Eighty-eight patients ( 22 % ) showed an elevated perioperative NT-proBNP value . When patients with either preoperatively or postoperatively elevated NT-proBNP were pooled , a greater incidence of AF was observed compared with patients with normal values ( 64 % versus 5 % ; P<0.001 ) . At multivariable analysis , adjusted for age , gender , major comorbidities , echocardiography parameters , pneumonectomy , and medications , both preoperative and postoperative NT-proBNP values were independent predictors of AF ( relative risk , 27.9 ; 95 % CI , 13.2 to 58.9 ; P<0.001 for preoperative NT-proBNP elevation ; relative risk , 20.1 ; 95 % CI , 5.8 to 69.4 ; P<0.001 for postoperative NT-proBNP elevation ) . Conclusions — Elevation of perioperative NT-proBNP is a strong independent predictor of postoperative AF in patients undergoing thoracic surgery for lung cancer . This finding should facilitate studies of therapies to reduce AF in selected high-risk patients OBJECTIVES This study was design ed to evaluate B-type natriuretic peptide ( BNP ) for risk assessment and clinical decision making over a range of cut points , alone and with cardiac troponin I ( cTnI ) , in patients with non-ST-elevation acute coronary syndromes ( ACS ) . BACKGROUND B-type natriuretic peptide holds promise for risk stratification . Additional evidence regarding optimal decision limits , use in combination with troponin , and use in targeting therapy is needed before acceptance into clinical use for ACS . METHODS We evaluated BNP at baseline in 1,676 patients with non-ST-elevation ACS r and omized to early invasive versus conservative management . RESULTS Patients with elevated BNP ( > 80 pg/ml ; n = 320 ) were at higher risk of death at seven days ( 2.5 % vs. 0.7 % , p = 0.006 ) and six months ( 8.4 % vs. 1.8 % , p < 0.0001 ) . The association between BNP and mortality at six months ( adjusted odds ratio [ OR ] 3.3 ; 95 % confidence interval [ CI ] 1.7 to 6.3 ) was independent of important clinical predictors , including cTnI and congestive heart failure ( CHF ) . Patients with elevated BNP had a fivefold higher risk of developing new CHF by 30 days ( 5.9 % vs. 1.0 % , p < 0.0001 ) . B-type natriuretic peptide added prognostic information to cTnI , discriminating patients at higher mortality risk among those with negative ( OR 6.9 ; 95 % CI 1.9 to 25.8 ) and positive ( OR 4.1 ; 95 % CI 1.9 to 9.0 ) baseline cTnI results . No difference was observed in the effect of invasive versus conservative management when stratified by baseline levels of BNP ( p(interaction ) > or = 0.6 ) . CONCLUSIONS Elevated BNP ( > 80 pg/ml ) at presentation identifies patients with non-ST-elevation ACS who are at higher risk of death and CHF and adds incremental information to cTnI. Additional work is needed to identify therapies that may reduce the risk associated with increased BNP We performed a Monte Carlo study to evaluate the effect of the number of events per variable ( EPV ) analyzed in logistic regression analysis . The simulations were based on data from a cardiac trial of 673 patients in which 252 deaths occurred and seven variables were cogent predictors of mortality ; the number of events per predictive variable was ( 252/7 =) 36 for the full sample . For the simulations , at values of EPV = 2 , 5 , 10 , 15 , 20 , and 25 , we r and omly generated 500 sample s of the 673 patients , chosen with replacement , according to a logistic model derived from the full sample . Simulation results for the regression coefficients for each variable in each group of 500 sample s were compared for bias , precision , and significance testing against the results of the model fitted to the original sample . For EPV values of 10 or greater , no major problems occurred . For EPV values less than 10 , however , the regression coefficients were biased in both positive and negative directions ; the large sample variance estimates from the logistic model both overestimated and underestimated the sample variance of the regression coefficients ; the 90 % confidence limits about the estimated values did not have proper coverage ; the Wald statistic was conservative under the null hypothesis ; and paradoxical associations ( significance in the wrong direction ) were increased . Although other factors ( such as the total number of events , or sample size ) may influence the validity of the logistic model , our findings indicate that low EPV can lead to major problems Background :  Postoperative cognitive dysfunction ( POCD ) is a significant cause of morbidity after noncardiac surgery . Identified risk factors are largely limited to demographic characteristics . We hypothesized that POCD was associated with apolipoprotein E4 ( APOE4 ) genotype and plasma biomarkers of brain injury and inflammation . Methods : Three hundred ninety-four patients older than 55 yr undergoing major elective noncardiac surgery were enrolled in this prospect i ve observational study . Apolipoprotein E genotyping was performed at baseline . Plasma was collected at baseline and end of surgery and at 4.5 , 24 , and 48-h postoperatively . Six protein biomarkers were assayed ( B-type natriuretic peptide , C-reactive protein , D-dimer , matrix metalloproteinase-9 , neuron-specific enolase , and S-100B ) . Neurocognitive testing was conducted at baseline and at 6 weeks and 1 yr after surgery ; scores were subjected to factor analysis . The association of APOE4 and biomarkers with POCD was tested using multivariable regression modeling . Results : Three hundred fifty patients ( 89 % ) completed 6-week neurocognitive testing . POCD occurred in 54.3 % of participants at 6 weeks and 46.1 % at 1 yr . There was no difference in POCD between patients with or without the APOE4 allele ( 56.6 vs. 52.6 % ; P = 0.58 ) . The continuous cognitive change score ( mean ± SD ) was similar between groups ( APOE4 : 0.05 ± 0.27 vs. non-APOE4 : 0.07 ± 0.28 ; P = 0.53 ) . Two hundred ninety-one subjects ( 74 % ) completed testing at 1 yr . POCD occurred in 45.9 % of APOE4 subjects versus 46.3 % of non-APOE4 subjects ( P = 0.95 ) . The cognitive score was again similar ( APOE4 : 0.08 ± 0.27 vs. non-APOE4 : 0.05 ± 0.25 ; P = 0.39 ) . Biomarker levels were not associated with APOE4 genotype or cognition at 6 weeks or 1 yr . Conclusion : Cognitive decline after major noncardiac surgery is not associated with APOE4 genotype or plasma biomarker levels OBJECTIVES The aim of this study was to evaluate whether chronic heart failure ( HF ) therapy guided by concentrations of amino-terminal pro-B-type natriuretic peptide ( NT-proBNP ) is superior to st and ard of care ( SOC ) management . BACKGROUND It is unclear whether st and ard HF treatment plus a goal of reducing NT-proBNP concentrations improves outcomes compared with st and ard management alone . METHODS In a prospect i ve single-center trial , 151 subjects with HF due to left ventricular ( LV ) systolic dysfunction were r and omized to receive either st and ard 
    Output:
    
Increased postoperative BNPs are independently associated with adverse cardiac events after noncardiac surgery