***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: Cardiac surgery with cardiopulmonary bypass is associated with a systemic inflammatory response . We examined combined use of heparin coating of the cardiopulmonary bypass circuit and a leukocyte-depleting arterial line filter to reduce this response . Thirty patients were allocated r and omly to equal groups with a conventional circuit and arterial line filter ( C group ) , a heparin-coated circuit with a conventional filter ( H group ) , or a heparin-coated circuit with a leukocyte-depleting arterial line filter ( HF group ) . Cytokines and respiratory function were repeatedly measured perioperatively . Plasma interleukin (IL)-6 concentrations in the HF group were lower than in the C group immediately following bypass and operation , at 4 h , and 12 h ( p < 0.05 ) . Plasma IL-8 was lower in the HF group than in the C group at 4 h ( p < 0.05 ) . The respiratory index was lower immediately after bypass in the HF group than the C group ( 0.61 + /- 0.2 versus 1.05 + /- 0.4 , p < 0.05 ) . Heparin-coated circuits with leukocyte-depleting filters decrease inflammatory responses and improve pulmonary function during operation Leukocyte mediated pulmonary injury may delay recovery after cardiac surgery , and leukocyte depletion during bypass has been suggested . Two groups of patients were r and omly , prospect ively assigned from 50 sequential patients to undergo open heart surgery using cardiopulmonary bypass , either with ( n = 25 ) or without ( n = 25 ) leukocyte filters . The two groups were not significantly different regarding age , gender , race , pre-operative ejection fraction , pump time , or cross-clamp time . Post operative arterial blood gases ( pO2 : 173 + /- 66 vs 192 + /- 107 ; pCO2 : 30.2 + /- 8.2 vs 30.8 + /- 8.0 ) , pulmonary vascular resistance ( PVR 105 + /- 45 vs 112 + /- 50 dyne cm-5 ) , time on ventilator ( 17.8 + /- 6.4 vs 19.7 + /- 8.6 hr ) , and length of hospital stay ( 7.65 + /- 4.57 vs 8.52 + /- 5.87 days ) were not different between groups ( mean + /- SD , with vs without filters , respectively ) . Arterial oxygenation was somewhat poorer , and PVR was somewhat lower in the leukocyte filtered group . However , these trends did not produce significant decreases in total ventilator time or length of hospital stay . In-line filtration did remove leukocytes , but did not reduce circulating leukocyte count . In effect , leukocyte filtration produced an effective leukocyte concentration at the filter site . These data do not support routine incorporation of in-line leukocyte filtration during bypass Each year , 600 000 patients undergo myocardial revascularization with cardiopulmonary bypass  and sustain profound physiologic perturbations that precipitate ischemia and infa rct ion in several organ systems [ 1 - 3 ] . Although medical re sources have been redirected to address perioperative cardiac and neurologic illness , the clinical effect of cardiac surgery on renal function has not been studied rigorously . Nonpulsatile blood flow , increases in levels of circulating catecholamines and inflammatory mediators , macroembolic and microembolic insults to the kidney , and release of free hemoglobin from traumatized erythrocytes result in numerous pathophysiologic renal responses [ 4 - 6 ] . Many studies [ 7 - 9 ] have shown that patients who have undergone cardiac surgery developed maldistributed renal blood flow , increases in renal vascular resistance , and substantive decreases ( 25 % to 75 % ) in renal blood flow and glomerular filtration rate . The effect of these phenomena on clinical outcome is not well known but is thought to be considerable . Studies have reported incidences of oliguric renal failure requiring dialysis as high as 5 % and mortality rates as great as 89 % . Previous studies [ 10 - 19 ] have many limitations because of a wide variability ( threefold or more ) in estimates of adverse renal outcomes : All of the studies were conducted at a single center , most were retrospective , and most were done more than a decade ago . No previous study provided adjusted estimates of risk factors ; in addition , the definition chosen for renal dysfunction was arbitrary , or the study sample consisted only of patients requiring dialysis [ 11 , 13 , 15 - 17 ] . Finally , few studies have investigated re source utilization in patients with renal dysfunction or failure . We therefore studied 2400 patients who underwent myocardial revascularization with cardiopulmonary bypass .  Our goals were to determine 1 ) the incidence and characteristics of postoperative renal dysfunction and failure , 2 ) the predictors of renal dysfunction [ determined by the use of multivariate modeling techniques ] , and 3 ) the effect of renal dysfunction on in-hospital re source utilization and patient disposition after discharge . Methods Patients The Multicenter Study for Perioperative Ischemia ( McSPI ) Research Group studied 2417 patients undergoing myocardial revascularization between 1991 and 1993 . Twenty-four diverse U.S. health care facilities-small and large academic institutions , private medical centers , health maintenance organization groups , and Veterans Affairs hospitals-participated in this study . Most patients were representative of consecutive patients seen at a given medical center . We enrolled every nth patient on the basis of a proportion of the site-specific expected annual caseload ( n = 2 through 30 in 24 centers ) . Comprehensive data were collected from preoperative cardiac , surgical , and medical histories ; invasive and noninvasive cardiologic testing ; surgical procedures and techniques ; perioperative hemodynamic events ; postoperative in-hospital events ( illness and death ) ; and hospital re source utilization . In addition , serial preoperative and postoperative 12-lead electrocardiograms were obtained and were central ly analyzed by a consensus panel of cardiologists . Serum creatinine values were recorded before and after surgery . Of the 2417 patients enrolled , 195 were excluded from analysis because of preexisting renal failure ( n = 99 ) or dysfunction ( serum creatinine level > 177 mol/L [ n = 81 ] ) or lack of perioperative serum creatinine measurements ( n = 68 ) . The latter group included patients who died before a postoperative sample could be obtained . Definitions of Renal Failure , Renal Dysfunction , and Comorbid Events Postoperative renal failure was defined by the need for dialysis after surgery . Renal dysfunction was defined as a postoperative serum creatinine level of 177 mol/L or greater and an increase in serum creatinine level of 62 mol/L or greater from preoperative to maximum postoperative values . The criteria for dysfunction were derived from the distribution of serum creatinine values in an uncomplicated patient subset . This subset excluded patients with preoperative renal disease ( serum creatinine level > 124 mol/L ) or medical risk factors ( age > 70 years ; history of congestive heart failure or type 1 diabetes mellitus ) , or a complicated postsurgical course ( in-hospital death ; concomitant valvular surgery ; intraaortic balloon pump insertion ; administration of at least three nonroutine inotropic drugs ; measures of hemodynamic instability ; ventricular fibrillation or dysrhythmia requiring a pacemaker ; complications necessitating a return to cardiopulmonary bypass , the intensive care unit , or the operating room ; or chest tube output exceeding 1 L/d ) . Less than 1 % of patients meeting these criteria had a maximum postoperative creatinine level greater than 177 mol/L and a maximum preoperative-to-postoperative change in creatinine level of 62 mol/L. Comorbid events , assessed through the first postoperative day , consisted of postoperative myocardial infa rct ion , congestive heart failure ( hemodynamic or clinical ) , use of an intraaortic balloon pump or other mechanical circulatory assist device , administration of three or more inotropic drugs , and hemorrhage . A myocardial infa rct ion was defined as either a Q-wave or a non-Q-wave infa rct ion . A Q-wave myocardial infa rct ion was diagnosed central ly by the presence of a new Q wave on each of two postoperative 12-lead electrocardiograms , as defined by Minnesota Code criteria , that were scored by a consensus panel of cardiologists . A non-Q-wave myocardial infa rct ion was determined by an elevated creatine kinase-MB level , a new wall-motion abnormality detected by echocardiography , or a new perfusion defect on a scintigraphy scan . Low output state [ an ordered , categorical variable ] was defined as one of the following : 1 ) severe ventricular dysfunction-intraaortic balloon pump counterpulsation required , 2 ) moderate ventricular dysfunction-hemodynamic congestive heart failure or at least three nonroutine inotropic drugs prescribed after surgery , and 3 ) mild ventricular dysfunction- clinical congestive heart failure . We defined hemodynamic congestive heart failure on the basis of a cardiac index less than 1.5 L/min per m2 body surface area for at least 30 minutes , a central venous pressure greater than 12 mm Hg , or a pulmonary artery occlusion pressure/left ventricular end diastolic pressure greater than 18 mm Hg . Clinical congestive heart failure was defined according to the presence of pulmonary rales , S3 gallop , or chest radiographic findings suggestive of heart failure . We defined hemorrhage as 1 ) chest tube output of at least 1 L/d , 2 ) return to the critical care unit or operating room within the first postoperative day because of bleeding , or 3 ) administration of three or more units of blood products in the operating room or critical care unit within 48 hours of surgery . Statistical Analysis Distributions and univariate measures of preoperative , postoperative , and preoperative-to-postoperative changes in serum creatinine values were examined . Unadjusted relative risks and 95 % CIs were calculated for all perioperative factors . Adjusted relative risk estimates were derived from multivariate logistic regression models because an 8 % incidence of renal dysfunction is relatively rare . Models were analyzed in a piece-wise fashion ( separate models were developed for each preoperative , operative , and postoperative period from the significant unadjusted factors in each period ) . A final model with adjusted estimates of relative risk was derived with factors that remained significant ( P 0.05 ) in the three time period models . Operative and postoperative variables were entered into the model in a forward stepwise fashion after adjustment for preoperative variables . No appreciable differences were noted when all perioperative factors were allowed to enter into the model in forward or backward stepwise selection procedures . The best-fitting models were selected from evaluation of the Hosmer-Lemeshow goodness-of-fit test statistic and the smallest values of the Akaike Information Criterion . The predictive ability of the models of preoperative risk factors alone , as well as the final model , were also evaluated with the area under the receiver-operating characteristic curve ( the concordance or c-index ) . The c-index was also derived from a validation process that involved comparison of the c-index derived from a r and om sample of half of the patients from each site and a computed c-index derived from modeling the remaining sample 's predicted probability of renal dysfunction calculated from the variable estimates from the original 50 % r and om sample . In other words , a predicted probability was derived from variable estimates from those obtained from the 50 % within-center sample ; these estimates were applied to the patients ' combination of risk factors in the remaining sample . The c-index was then calculated from modeling the remaining sample 's predicted probabilities as a single predictor . From the final model of preoperative risk factors , both observed and predicted probabilities were described and the sensitivity and specificity of the preoperative model were reported . The sensitivity and specificity were determined by selecting the highest sensitivity and specificity from a classification table of observed and predicted events ( this occurred with a probability of renal dysfunction 6 % ) . Theoretically , each of the 24 medical centers in the study sample may have characteristics that were not measured and could have influenced patients ' outcomes . To address potential within-center correlation , ancillary analyses were conducted . Logistic regression models using generalized estimating equations with an exchangeable correlation matrix were used to account for within-center correlation . Estimates of SEs are considered corrected for potential within-center AIMS To identify the characteristics , treatment , and outcomes of contemporary patients with valvular heart disease ( VHD ) in Europe , and to examine adherence to guidelines . METHODS AND RESULTS The Euro Heart Survey on VHD was conducted from April to July 2001 in 92 centres from 25 countries ; it included prospect ively 5001 adults with moderate to severe native VHD , infective endocarditis , or previous valve intervention . VHD was native in 71.9 % of patients and 28.1 % had had a previous intervention . Mean age was 64+/-14 years .  Degenerative aetiologies were the most frequent in aortic VHD and mitral regurgitation while most cases of mitral stenosis were of rheumatic origin . Coronary angiography was used in 85.2 % of patients before intervention . Of the 1269 patients who underwent intervention ,  prosthetic replacement  was performed in 99.0 % of aort 
    Output:
    
tubular or glomerular kidney injury , 2 .