***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*** 
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    Input: OBJECTIVES Cardiopulmonary bypass ( CPB ) is widely regarded as an important contributor to renal failure , a well recognized complication following coronary artery surgery ( coronary artery bypass grafting ( CABG ) ) . Anecdotally off-pump coronary surgery ( OPCAB ) is considered renoprotective . We examine the extent of renal glomerular and tubular injury in low-risk patients undergoing either OPCAB or on-pump coronary artery bypass ( ONCAB ) .  METHODS Forty low-risk patients with normal preoperative cardiac and renal functions awaiting elective CABG were prospect ively r and omized into those undergoing OPCAB ( n=20 ) and ONCAB ( n=20 ) . Glomerular and tubular injury were measured respectively by urinary excretion of microalbumin and retinol binding protein ( RBP ) indexed to creatinine ( Cr ) . Daily measurements were taken from admission to postoperative day 5 . Fluid balance , serum Cr and blood urea were also monitored . RESULTS No mortality or renal complication were observed . Both groups had similar demographic makeup , Parsonnet score , functional status and extent of coronary revascularization ( 2.1+/-1.0 vs. 2.5+/-0.7 grafts ; P=0.08 ) . Serum Cr and blood urea remained normal in both groups throughout the study . A significant and similar rise in urinary RBP : Cr occurred in both groups peaking on day 1 ( 3183+/-2534 vs. 4035+/-4079 ; P=0.43 ) before reapproximating baseline levels . These trends were also observed with urinary microalbumin : Cr ( 5.05+/-2.66 vs. 6.77+/-5.76 ; P=0.22 ) . Group B patients had a significantly more negative fluid balance on postoperative day 2 ( -183+/-1118 vs. 637+/-847 ml ; P=0.03 ) . CONCLUSIONS Although renal complication or serum markers of kidney dysfunction were absent , sensitive indicators revealed significant and similar injury to renal tubules and glomeruli following either OPCAB or ONCAB . These results suggest that avoidance of CPB does not offer additional renoprotection to patients at low risk of perioperative renal insult during CABG BACKGROUND Pulmonary dysfunction is still a major problem in coronary artery bypass grafting ( CABG ) . The purpose of this r and omized study was to determine the effect of different CABG techniques on pulmonary function . METHODS Fifty eight patients with severe obstructive pulmonary disease had elective isolated coronary surgery .  The surgical methods for the patients with chronic obstructive pulmonary disease ( COPD ) were st and ard CABG in 18 patients ( group 1 ) , beating heart surgery in 19 patients ( group 2 ) , and minimally invasive direct coronary artery bypass grafting ( MIDCABG ) in 21 patients ( group 3 ) . RESULTS The earliest extubation time was from group 3 ( p < 0.001 ) . The average stay in the intensive care unit was significantly longer in group 1 ( 2.6 + /- 1.5 days ) than in groups 2 ( 1.4 + /- 0.8 days ) and 3 ( 1.1 + /- 0.8 days ) ( p < 0.05 ) . The most prevalent respiratory morbidity was atelectasis that developed in 6 patients from group 1 , in 2 patients from group 2 , and in 3 patients from group 3 . Forced expiratory volumes in 1 second ( FEV1 ) obtained in the second postoperative month were significantly lower than preoperative values only in group 1 ( p < 0.05 ) . Forced vital capacity ( FVC ) values were significantly lower than the preoperative values in all three groups ( p < 0.05 ) . CONCLUSIONS Off-pump bypass surgical procedures are more advantageous than on-pump methods for patients with COPD . These patients can be operated on using the beating heart technique or by using MIDCABG to prevent side effects of CPB on pulmonary function and effects of sternotomy BACKGROUND Coronary artery bypass surgery with cardiopulmonary bypass carries a significant risk of perioperative brain injury . At least 1 % to 5 % will suffer a stroke , and at 3-months postoperatively approximately 30 % are reported to have cognitive impairment assessed by neuropsychologic testing . In off-pump surgery cardiopulmonary bypass is not used and instrumentation on the ascending aorta is reduced . The main aim of this study was to assess if off-pump surgery reduces intraoperative cerebral embolization . METHODS This was a prospect i ve and r and omized study of two comparable groups with regard to age , sex , years of education , preoperative cognitive functioning , and surgical characteristics . Fifty-two patients ( 29 off-pump ) were monitored by the use of transcranial Doppler ultrasound for cerebral microembolization during surgery . Preoperative and postoperative clinical , cerebral magnetic resonance imaging , and neuropsychologic examinations were also carried out . RESULTS There was a significant reduction in the number of cerebral microemboli during off-pump compared with on-pump surgery ( 16.3 [ range 0 to 131 ] versus 90.0 [ range 15 to 274 ] , p < 0.0001 ) . No significant difference with regard to the incidence of neuropsychologic performance ( decline in 29 % off-pump , 35 % on-pump ) or neuroradiologic findings at 3 months was found , and there was no association between the number of cerebral microemboli and cognitive outcome . CONCLUSIONS This study clearly demonstrates that off-pump surgery leads to a reduction in intraoperative cerebral microembolization . A significant reduction in the number of off-pump patients with cognitive decline or ischemic brain lesions on cerebral magnetic resonance imaging could not be demonstrated in this relatively small patient population BACKGROUND Although no r and omised controlled trial has assessed the midterm effects of coronary-artery bypass surgery on the beating heart , this technique is being used in more and more patients . We did two r and omised trials to compare the short-term morbidity associated with off-pump and on-pump myocardial revascularisation . Our aim was to pool the results to assess midterm outcomes . METHODS From March , 1997 , to November , 1999 , we r and omly allocated 200 patients to off-pump and 201 to on-pump coronary surgery .  In Beating Heart Against Cardioplegic Arrest Study ( BHACAS ) 1 , we excluded patients who had had myocardial infa rct ion in the past month or who required grafting of the circumflex artery distal to the first obtuse marginal branch . In BHACAS 2 , we included such patients . Primary outcomes were all-cause mortality and cardiac-related events at midterm follow-up ( 1 - 3 years ) . Analysis was by intention to treat . FINDINGS Analyses of combined data from both trials showed the following risk differences with off-pump compared with on-pump surgery :  atrial fibrillation -25 % ( 95 % CI -33 % to -16 % ) ; chest infection -12 % ( -19 % to -5 % ) ; inotropic requirement -18 % ( -25 % to -10 % ) ; transfusion of red blood cells -31 % ( -41 to -21 ) ; and hospital stay longer than 7 days -13 % ( -21 to -5 ) . Mean follow-up was 25 0 months ( SD 9.1 ) for BHACAS 1 and 13.7 months ( 5 5 ) for BHACAS 2 . Four ( 2 % ) of 200 patients in the off-pump groups died from any cause , compared with seven ( 3 % ) of 201 in the on-pump group ( hazard ratio 0.57 , 95 % CI 0.17 - 1.96 ) . 33 ( 17 % ) of 200 patients in the off-pump group died or had a cardiac-related event , compared with 42 ( 21 % ) of 201 in the on-pump group ( 0.78 , 0 49 - 1.22 ) . INTERPRETATION Off-pump coronary surgery significantly lowers in-hospital morbidity without compromising outcome in the first 1 - 3 years after surgery compared with conventional on-pump coronary surgery BACKGROUND We investigated whether off-pump coronary artery bypass ( OPCAB ) surgery should be the procedure of choice in total arterial myocardial revascularization with composite grafts . METHODS We prospect ively enrolled 176 patients undergoing total arterial myocardial revascularization and assigned them at r and om to one of two groups : group 1 was composed of 88 patients undergoing coronary surgery with cardiopulmonary bypass ( CPB ) ; group 2 consisted of 88 patients receiving the OPCAB procedure .  We excluded from this study patients with significant risk factors for CPB-related morbidity .  Composite arterial grafts in Y-T shape were realized in three different configurations according to patients ' characteristics , coronary anatomy , and target stenosis . RESULTS There were no significant differences between the two groups in terms of preoperative characteristics and  risk factors ( Euroscore : group 1 = 6.1 + /- 3.5 , group 2 = 6.6 + /- 3.8 ) . Mean number of anastomoses was similar in both groups ( group 1 = 2.8 + /- 0.8 , group 2 = 2.7 + /- 0.5 ) whereas mean mechanical ventilation time ( group 1 = 23 + /- 9 hours , group 2 = 9 + /- 4 hours ) , intensive care unit stay ( group 1 = 43 + /- 6 hours , group 2 = 22 + /- 8 hours ) , and postoperative stay ( group 1 = 7 + /- 3 days , group 2 = 5 + /- 2 days ) were significantly reduced in group 2 . Early mortality was 2.3 % in group 1 and 3.4 % in group 2 ( p = not significant ) . Major postoperative complications occurred similarly in the two groups ( atrial fibrillation : group 1 = 35.2 % , group 2 = 21.6 % ; myocardial infa rct ion : group 1 = 2.2 % , group 2 = 1.1 % ; stroke : group 1 = 2.2 % , group 2 = 0 % ; abdominal infa rct ion : group 1 = 3.4 % , group 2 = 0 % ) . At follow-up ( mean , 15 + /- 12 months ) no significant differences were observed in terms of survival free of any cardiac-related event ( group 1 = 94.3 % , group 2 = 96.5 % ; p = not significant ) . CONCLUSIONS Off-pump coronary artery surgery could be successfully used for total arterial grafting without compromising the completeness of revascularization . Avoidance of CPB significantly decreased mechanical ventilation support and length of intensive care unit and postoperative stay ; however in the absence of risk factors for cardiopulmonary bypass , off-pump coronary artery surgery did not improve early and midterm clinical outcome BACKGROUND The interpretation of the results of r and omized controlled trials ( RCTs ) has traditionally emphasized statistical significance rather than clinical importance . Our aim was to assess the quality of reporting of factors related to clinical importance in a sample of published RCTs . METHODS A r and om sample of 27 ( of a total of 266 ) RCTs published in 5 major medical journals over a 1-year period were review ed by 4 independent review ers for factors considered important in the interpretation of the clinical importance of study results : identification of a clearly defined primary outcome , reporting of the expected difference between groups used in the calculation of sample size ( the delta value ) and whether it was based on the minimal clinical ly important difference of the intervention , the statistical significance of the results , presentation of pertinent confidence intervals , and the authors ' interpretation of the clinical importance of the results . RESULTS Twenty-two of 27 ( 81 % ) articles explicitly reported a single primary outcome . Of the 20 articles that included a sample size calculation , 18 ( 90 % ) reported a delta value . Two of the 18 ( 11 % ) articles explicitly stated that the delta value was chosen to reflect the minimal clinical ly important difference of the intervention . For the primary outcomes , confidence intervals surrounding the point estimates of the efficacy of the interventions were reported in 11 of 27 ( 41 % ) studies . The study results were interpreted from the perspective of clinical importance in 20 of 27 ( 74 % ) of the articles . Of these 20 reports , 5 ( 25 % ) provided justification for their clinical interpretation of the results . INTERPRETATION Authors of RCTs published in major general medical and internal medicine journals do not consistently provide their own interpretation of the clinical importance of their results , and they often do not provide sufficient information to allow readers to make their own interpretation BACKGROUND There is increased interest in coronary artery bypass grafting ( CABG ) without cardiopulmonary bypass ( CPB ) , although the preservation of the myocardium under such circumstances has not been properly investigated . The aim of this r and omized study was to compare the changes in myocardial metabolism during CABG with and without CPB . METHODS Myocardial energy metabolism and tissue injury during CABG was monitored in a series of  
    Output:
    
With GEE modelling , the reporting quality had a strong association with trial size , publication year , trial location and funding source , but not with the results and type of primary outcome .