***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 
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    Input: 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 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 Stroke is a devastating complication of coronary artery bypass grafting ( CABG ) . This study was carried out with the aim that the development of off pump coronary artery surgery decreases the incidence/adverse outcome due to extra corporeal circulation . METHODS The data utilized in this study was extracted from a r and omized controlled trial that was conducted from January 2006 to March 2007 at Punjab Institute of Cardiology . One hundred patients were included in ' on pump ' group-A , and 100 patients in ' off pump ' group-B. RESULTS The mean age of the patients in group-A was 53.51 ± 9.96 years and in group-B it was 51.59 ± 10.30 years . Renal failure occurred in 21 % patients of group-A as compared to 10 % of group-B while Acute Myocardial Infa rct ion occurred in significantly higher number of patients in group-B ( 11 % ) as compared to group-A ( 2 % ) . Off pump was associated with significant decrease in rate of stroke 1.5 % as compared to on pump 3.5 % . similarly there was decreased in the risk of deaths after stroke 0 % as compared to on pump 1.5 % mortality after stroke . In group A 6 ( 3.5 % ) patients developed stroke where as in group-B 2 ( 1.5 % ) patients developed stroke out of these 6 patients there were 2 mortalities after stroke in group-A while in group-B there was no mortality after stroke within 30 days postoperatively . CONCLUSION Off pump CABG is associated with significantly decreased rate of stroke in comparison with the on-pump CABG 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 The objective of this study is to evaluate the costs and health benefits of coronary artery bypass grafting ( CABG ) surgery with and without cardiopulmonary bypass ( CPB ) . R and omized controlled clinical trial is used as the design . The setting is in a single tertiary cardiothoracic center in Middlesex , UK . Participants were 168 patients ( 27 females ) requiring primary isolated CABG surgery . Patients were r and omized to have the procedure performed by a single surgeon either with CPB ( n = 84 ) or by an off-pump coronary artery bypass ( OPCAB ) surgery ( n = 84 ) .  Health-related quality of life was assessed at baseline , 6 weeks , and 6 months using the World Health Organization Quality -of-Life ( WHOQOL-100 ) question naire . Mean total costs of patient management by either technique were calculated using different available key sources . A utility measure , derived from WHOQOL-100 , was used to calculate quality -adjusted life year ( QALY ) gained in each group , on basis of which a cost-effectiveness analysis was performed . The mean total costs of an OPCAB patient was 5859 pounds , whereas for a CPB patient it was 7431 pounds with a mean difference of 1572 pounds ( st and ard error [ SE ] 674 pounds ; P = 0.02 ) . Three patients died in the CPB group and two in the OPCAB group during the 6-month follow-up period . Mean QALYs over 6 months was 0.379 in the OPCAB group and 0.362 in the CPB group , but the difference was not significant ( mean difference 0.017 ; SE 0.016 ; P = 0.305 ) . OPCAB surgery offered patients in this r and omized trial similar health benefits to CPB over a 6-month period , but at a significantly less cost Background  Atrial fibrillation ( AF )  increases the morbidity of CABG . The pathophysiology is uncertain , and its prevention remains suboptimal . This prospect i ve , r and omized study was design ed to define the role of cardiopulmonary bypass ( CPB ) and cardioplegic arrest in the pathogenesis of this complication . Methods 
    Output:
    
Off-pump CABG has some benefits over on-pump CABG , particularly in relation to post-operative atrial fibrillation