***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 —Diagnosis of coronary artery disease in women is more difficult because of lower specificity of symptoms and diagnostic accuracy of noninvasive testing . We sought to examine the relationship between gender and cardiac biomarkers in patients with unstable angina (UA)/non – ST-segment elevation myocardial infa rct ion ( NSTEMI ) . Methods and Results —In the TACTICS-TIMI 18 , OPUS-TIMI 16 , and TIMI 11 studies , baseline sample s were analyzed in the Thrombolysis In Myocardial Infa rct ion ( TIMI ) biomarker core laboratory . We examined the relationship between gender and elevated biomarkers . Of 1865 patients from TACTICS-TIMI 18 , 34 % were women . Fewer women had elevated creatine kinase-MB or troponins , whereas more had elevated high-sensitivity C-reactive protein or brain natriuretic peptide . Presence of ST-segment deviation and TIMI risk scores were not significantly different . This pattern was confirmed in TIMI 11 and OPUS-TIMI 16 . The prognostic value of the markers in TACTICS-TIMI 18 was similar in women and men . When a multimarker approach was examined , a greater proportion of high-risk women were identified . Marker-positive patients of both genders had improved outcome with an invasive strategy ; however , marker-negative women appeared to have improved outcomes with a conservative strategy . Conclusions —In patients with UA/NSTEMI , there was a different pattern of presenting biomarkers . Men were more likely to have elevated creatine kinase-MB and troponins , whereas women were more likely to have elevated C-reactive protein and brain natriuretic peptide . This suggests that a multimarker approach may aid the initial risk assessment of UA/NSTEMI , especially in women . Further research is necessary to eluci date whether gender-related pathophysiological differences exist in presentation with acute coronary syndromes 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 N-terminal pro-B-type natriuretic peptide ( NT-proBNP ) is increasingly being used as a biomarker of cardiovascular risk . To date neither its cut-off for postoperative period in noncardiac surgery nor whether the cardiovascular risk has any relation to natriuresis has been assessed . DESIGN The prospect i ve observational study evaluated postoperative serum levels of NT-proBNP with fractional excretion of sodium ( FENa+ ) and sodium clearance ( CNa+ ) in relation to the occurrence of cardiovascular events in patients after elective cervical spine surgery . METHODS In 27 otherwise healthy patients after elective cervical spine surgery we prospect ively measured serum NT-proBNP and serum sodium  immediately after the operation ( day 1 ) and on day two . We correlated both NT-proBNP with FENa+ , CNa+ , diuresis and intake of fluids and sodium , which were assessed from the beginning of the operation until day two . We followed the incidence of myocardial infa rct ion , heart failure and cardiac death postoperatively to 1 year . RESULTS Immediate postoperative NT-proBNP values were within the reference range ( mean 4.53 ± 2.48 pmol/l ) , but they increased significantly on the second day ( mean 23.57 ± 12.27 pmol/l , p<0.001 ) . Significantly elevated CNa+ ( 0.033 ± 0.014 ml/s , p<0.001 ) , FENa+ ( 0.018 ± 0.008 , p<0.001 ) and fUNa+ ( mean 326.9 ± 125.2 mmol , p<0.01 ) were found . There was a significant positive correlation between the two values of NT-proBNP ( r=0.47 , p=0.014 ) , but we did not find any correlation between NT-proBNP and the further measured parameters . None of the patients had any cardiovascular events from operation until 1 year . CONCLUSIONS The significant postoperative elevation of NT-proBNP had no relationship with the rise in FENa+ , CNa+ or fUNa+ and was not connected with any occurrence of cardiovascular events in patients after elective cervical spine surgery OBJECTIVES The first aim of the present study was to evaluate the pre- and postoperative  B-type natriuretic peptide ( BNP ) levels in patients undergoing surgery for repair of an infrarenal abdominal aortic aneurysm ( AAA ) and analyze their power as a predictor of in-hospital cardiac events . The second aim was to evaluate the association among pre- and postoperative BNP levels , postoperative patient complications , and length of hospital stay . DESIGN Prospect i ve observational study . SETTING A university hospital . PARTICIPANTS Forty-five patients undergoing elective surgery for an abdominal aortic aneurysm . INTERVENTIONS The  plasma BNP level was assessed just before surgery and then on postoperative day 1 . Cardiac troponin I levels were measured postoperatively on arrival to the intensive care unit ( time 0 ) and then 12 , 48 , and 72 hours later . MEASUREMENTS AND MAIN RESULTS The preoperative BNP concentration in patients who developed an acute myocardial infa rct ion was 209 ( IQR 84 - 346 ) pg/mL compared with 74 ( IQR 28 - 142 ) pg/mL in those who did not . The difference between groups was statistically significant ( p = 0.04 ) . The Spearman correlation showed that postoperative BNP levels correlated significantly with preoperative BNP levels ( r = 0.73 , p = 0.0001 ) , length of hospital stay ( r = 0.35 , p = 0.04 ) , and troponin I concentration at 0 hour ( r = 0.42 , p = 0.02 ) , 12 hours ( r = 0.51 , p = 0.0052 ) , and 48 hours ( r = 0.40 , p = 0.033 ) . In contrast , preoperative BNP levels correlated with troponin I at only 12 hours ( r = 0.34 , p = 0.02 ) . Postoperative BNP levels were influenced significantly by transfusions ( p = 0.035 ) and cross-clamping times ( p = 0.038 ) . CONCLUSIONS The present results confirm the high negative predictive value of preoperative BNP levels ; and postoperative BNP levels showed a better correlation with postoperative troponin levels , blood transfusion , and postoperative cardiac events OBJECTIVES  Postoperative atrial fibrillation ( POAF ) complicating general thoracic surgery is a marker of increased morbidity and stroke risk . Our goal was to determine whether increased preoperative brain natriuretic peptide ( BNP ) levels are able to stratify patients by the risk of POAF . METHODS Using a prospect i ve data base of 415 patients aged 60 years or older , who had undergone lung or esophageal surgery during a 1-year period , the preoperative clinical data , including BNP levels , were compared between patients who developed POAF lasting longer than 5 minutes during hospitalization and those who did not . RESULTS POAF occurred in 65 ( 16 % ) of the 415 patients and was more frequent among patients who had undergone esophagectomy or anatomic lung resection  ( 22 % or 58 of 269 ) compared with those who did not ( 5 % or 7 of 146 ; P < .0001 ) . After esophagectomy or anatomic lung resection , 46 ( 34 % ) of the 135 patients with BNP levels greater than the median ( ≥ 30 pg/mL ) developed POAF compared with only 12 ( 9 % ) of 134 patients with BNP levels less than 30 pg/mL ( P < .0001 ) . The rates of POAF in patients undergoing other thoracic procedures were low and not associated with the BNP levels . Multivariate logistic regression analysis showed that in patients undergoing esophagectomy or anatomic lung resection , older age ( 5-year increments , odds ratio [ OR ] , 1.28 ; 95 % confidence interval [ CI ] , 1.01 - 1.61 ; P = .04 ) , male gender ( OR , 2.61 ; 95 % CI , 1.12 - 4.17 ; P = .02 ) , and BNP level 30 pg/mL or greater ( OR , 4.52 ; 95 % CI , 2.19 - 9.32 ; P < .0001 ) were independent risk factors for POAF . The length of hospital stay was significantly increased in patients who developed POAF compared with those who did not ( P < .0001 ) . CONCLUSIONS Among patients undergoing anatomic lung resection or esophagectomy  , increased age , male gender , and preoperative BNP level of 30 pg/mL or greater were significant risk factors for the development of POAF . The identification of patients who are more likely to develop POAF will allow the development of trials assessing prevention strategies aim ed at reducing this complication BACKGROUND [ Corrected ] Clinical assessment is not always sufficient to predict postoperative ( PO ) cardiac complications .  B-type natriuretic peptide ( BNP ) has an important prognostic value in patients with heart failure . Its value as a predictor of events in orthopedic surgeries has not yet been tested . OBJECTIVE To assess the value of BNP in predicting cardiac complications in the PO period of orthopedic surgeries . METHODS A total of 208 patients undergoing surgical treatment of femur fracture and hip or knee arthroplasty were prospect ively evaluated . Of these , 149 ( 71.6 % ) were women and the mean age was 72.6 ± 8.8 years . In the preoperative period , the patients underwent conventional clinical assessment and their surgical risk was estimated according to the American Society of Anesthesiologists ' ( ASA ) classification . BNP was determined in the preoperative period , and its ability to predict PO cardiac events ( death ; acute myocardial infa rct ion ; unstable angina ; atrial fibrillation ; ventricular tachycardia ; or heart failure ) was analyzed using multivariate logistic regression analysis . RESULTS Seventeen patients ( 8.0 % ) experienced cardiac events . Median BNP was significantly higher in these patients in comparison to those without cardiac events ( 93 [ interquartile range 73 - 424 ] vs 26.6 [ 13.2 - 53.1 ] , p = 0.0001 ) . BNP was the main independent predictor of events ( p = 0.01 ) . The ASA classification was not an independent predictor . Analysis of the ROC curve demonstrated that for a cut-off point of 60 pg/mL , BNP showed sensitivity of 76.0 % and specificity of 79.0 % in the prediction of events , with an area under the curve of 83.0 % . CONCLUSION BNP is an independent predictor of PO cardiac events in orthopedic surgeries OBJECTIVES To determine if troponin I and NT-proBNP were predictors of 6-month mortality after emergency  orthopedic-geriatric surgery in a frail population . DESIGN Prospect i ve observational study . SETTING Orthopedic-geriatric unit of a metropolitan hospital in Australia . PARTICIPANTS A total of  
    Output:
    
Patients with an elevated preoperative NP measurement are at an increased risk of postoperative AF .