***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: 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 AIMS Uncertainty persists regarding the impact of the off-pump technique on coronary bypass graft patency . The primary objective of this study was to assess coronary artery bypass graft patency in patients r and omized to off-pump and on-pump multivessel coronary artery bypass grafting ( CABG ) .  Secondary objectives were clinical outcomes and neuropsychological functioning . METHODS AND RESULTS One hundred and fifty patients were r and omized to off-pump ( n = 75 ) or on-pump CABG ( n = 75 ) .  Graft patency was assessed by multidetector computed tomography 5 weeks after surgery . The two groups were similar regarding patients ' characteristics and logistic Euroscore ( 3.6 vs. 3.7 % )  . Mean number of grafts performed was 3.5 ± 0.6 and 3.5 ± 0.6 in off-pump and on-pump , respectively ( P = 0.7 ) . Raw graft patency rate was 89.9 % in off-pump and 95.0 % in on-pump ( OR 2.2 , 95 % CI 1.07 - 4.44 ; P = 0.03 ) . Nineteen ( 27 % ) off-pump and 9 ( 13 % ) on-pump patients had at least one occluded graft ( P = 0.04 ) and the proportion of patent grafts per patient was 0.91 ± 0.2 in off-pump vs. 0.96 ± 0.1 in on-pump ( P = 0.06 ) . However , after adjusting by heparin dose , graft patency was not statistically different between groups ( OR 0.87 , 95 % CI 0.25 - 2.98 , P = 0.83 ) . At 30 days , there was no statistically significant difference in major adverse events and neuropsychological functioning between off-pump and on-pump groups . One-year follow-up showed similar functional class and positive treadmill exercise tests . CONCLUSIONS Under the conditions this trial was conducted , CABG performed off-pump had lower overall graft patency rate than on-pump , which was not statistically different after controlling for total heparin dose . Thirty-day complications , neuropsychological functioning , and one-year clinical and functional outcomes were not statistically different between the two techniques OBJECTIVE Cardiopulmonary bypass ( CPB ) is associated with gut mucosal hypoxia , which may contribute to gastrointestinal complications . We examined gastric mucosal oxygenation together with whole-body oxygen flux in low-risk patients undergoing coronary artery bypass grafting ( CABG ) with and without CPB .  METHODS Fifty-four patients undergoing primary CABG by the same surgeon were r and omized into either on-pump ( ONCAB , n=27 ) or off-pump ( OPCAB , n=27 ) groups . The ONCAB group underwent mild hypothermic ( 35 degrees C ) pulsatile CPB with arterial line filtration . Each patient underwent perioperative monitoring with continuous tonometry and cardiac output devices .  Gastric intramucosal pH ( pHi ) , gastric-arterial carbon dioxide partial pressure difference ( CO(2 ) gap ) , whole-body oxygen delivery ( DO(2 ) ) and consumption ( VO(2 ) ) and whole-body oxygen extraction fraction were measured at sequential time-points intraoperatively and up to 6 h postoperatively . Anaesthetic management was st and ardized . RESULTS Both groups had similar demographic makeup and extent of revascularization ( ONCAB 2.6+/-0.9 grafts versus OPCAB 2.5+/-0.8 grafts ; P=0.55 ) . The ONCAB group had a mean ( + /-SD ) CPB time of 62+/-25 min and aortic cross-clamp time of 32+/-11 min . In both groups there was a similar and progressive drop in pHi intraoperatively . Postoperatively , there was a gradual separation between the groups with ONCAB patients showing no further decline in pHi , while further deterioration was observed in the OPCAB group up to 6 h postoperatively . There was a significant difference between the groups over time ( P=0.03 ) . There was a corresponding progressive rise in CO(2 ) gap perioperatively in both groups , with ONCAB patients demonstrating superior preservation of gastric mucosal oxygenation in the early postoperative period . Global oxygen utilization measurements showed superior DO(2 ) and VO(2 ) in the OPCAB group throughout the study . CONCLUSIONS Despite superior global oxygen flux associated with beating-heart revascularization , gastric mucosal hypoxia occurred to similar extents in both groups with worsening trends for the OPCAB patients postoperatively . The splanchnic pathophysiology during beating-heart revascularization should be further explored 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 OBJECTIVE Age is considered to be the strongest predictive factor of postoperative cognitive dysfunction ( POCD )  after cardiac surgery .  Coronary artery bypass grafting ( CABG ) without the use of cardiopulmonary bypass is considered to be less harmful to the patient , especially in terms of neurological complications . METHODS The study was a sub- study of the r and omized best bypass surgery trial that compares off-pump to on-pump treatment , with respect to peri- and postoperative morbidity in patients with a moderate to high-predicted preoperative risk . We investigated cognitive outcomes .  A total of 120 elderly patients ( mean age 76 years , SD 4.5 years ) underwent  cognitive testing  before surgery , of which 90 patients ( 47 vs 43 ) were available for retesting at 1 year ( mean 370 days ) postoperatively , using a neuropsychological test battery that included seven parameters from four tests . POCD was defined as the occurrence of at least two deficits out of the seven possible scores . Secondary analysis was performed based on definition of 20 % decline in cognitive scores compared to baseline , and using z-score analysis . RESULTS The incidence of POCD was 19 % ( 95 % CI 9 - 33 ) in the off-pump group and 9 % ( 95 % CI 3 - 22 ) in the on-pump group ( p=0.18 ) . There were no significant differences in the incidence of cognitive decline between the off-pump and on-pump group regardless of the definition applied . CONCLUSIONS We were unable to detect that CABG surgery without cardiopulmonary bypass was associated with significantly better cognitive outcome in elderly high-risk patients 1 year after the operation BACKGROUND The development of new surgical devices and techniques allows off pump coronary artery bypass grafting ( OPCAB ) without the use of CPB and cardioplegia . This study tested whether OPCAB reduces myocardial cell damage , lipid peroxidation and systemic endothelin release when compared to conventional coronary artery bypass grafting . METHODS Twenty-six patients were assigned to either the OPCAB procedure using a suction device and regular sternotomy ( n = 13 ) or were treated conventionally using extracorporeal circulation , blood cardioplegia and hypothermic arrest ( 29 - 31 degrees C ; n = 13 ) . Troponin I and creatine kinase - MB were determined for cardiac specific cell damage . Myocardial and systemic malondialdhyde levels were measured to account for oxyradical mediated lipid peroxidation . Systemic big-endothelin levels were determined as a marker for 
    Output:
    
Our systematic review did not demonstrate any significant benefit of off-pump compared with on-pump CABG regarding mortality , stroke , or myocardial infa rct ion .
In contrast , we observed better long-term survival in the group of patients undergoing on-pump CABG  with the use of cardiopulmonary bypass and cardioplegic arrest .
Based on the current evidence , on-pump CABG should continue to be the st and ard surgical treatment .
However , off-pump CABG may be acceptable when there are contraindications for cannulation of the aorta and cardiopulmonary bypass .