***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 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 Between August 2004 and May 2006 , 124 patients undergoing coronary artery bypass grafting with ejection fractions ≤ 35 % were r and omly assigned to off-pump or conventional procedures . Preoperative characteristics were the same in both groups , except for age and degree of mitral regurgitation . Off-pump coronary artery grafting was carried out using a tissue stabilizer and a single-suture technique ; conventional coronary bypass employed cardiopulmonary bypass , moderate hypothermia , and ante grade -retro grade cold blood cardioplegic arrest . There were significantly fewer vessels grafted ( 3.09 ± 0.41 ) in the off-pump group than in those who had a conventional procedure ( 3.42 ± 0.86 ) . The rates of mortality , morbidity , balloon pump support , inotropic usage , gastrointestinal bleeding , renal dysfunction , reintubation , as well as intensive care and hospital stay , were significantly lower in the off-pump group . The incidence of perioperative myocardial infa rct ion did not differ significantly between groups . The results of this study indicate that beating-heart coronary bypass is safe and effective in patients with left ventricular dysfunction BACKGROUND The performance of  coronary bypass surgery without cardiopulmonary bypass ( " off pump " ) may reduce perioperative morbidity and costs , but it is uncertain whether the outcome is similar to that involving the use of cardiopulmonary bypass ( " on pump " ) . METHODS In a multicenter , r and omized trial , we r and omly assigned 139 patients with predominantly single- or double-vessel coronary disease to on-pump surgery and 142 to off-pump surgery .  Cardiac outcome and cost effectiveness were determined one year after surgery . The uncertainty surrounding the cost-effectiveness ratio ( cost differences per quality -adjusted year of life gained ) was addressed by bootstrapping . RESULTS At one year , the rate of freedom from death , stroke , myocardial infa rct ion , and coronary reintervention was 90.6 percent after on-pump surgery and 88.0 percent after off-pump surgery ( absolute difference , 2.6 percent ; 95 percent confidence interval , - 4.6 to 9.8 ) . Graft patency in a r and omized subgroup of patients was 93 percent after on-pump surgery and 91 percent after off-pump surgery ( absolute difference , 2.0 percent ; 95 percent confidence interval , - 6.5 to 10.4 ) . On-pump surgery was associated with $ 1,839 in additional direct costs per patient ( $ 14,908 vs. $ 13,069 - -a difference of 14.1 percent ) and an increase in quality -adjusted years of life of 0.83 as compared with 0.82 ( difference , 0.01 year ; 95 percent confidence interval , - 0.03 to 0.04 ) . Off-pump surgery was more cost effective than on-pump surgery in 95 percent of bootstrap estimates . CONCLUSIONS In low-risk patients , there was no difference in cardiac outcome at one year between those who underwent on-pump bypass surgery and those who underwent off-pump surgery . Off-pump surgery was more cost effective BACKGROUND In some r and omized trials comparing revascularization strategies for patients with diabetes , coronary-artery bypass grafting ( CABG ) has had a better outcome than percutaneous coronary intervention ( PCI ) . We sought to discover whether aggressive medical therapy and the use of drug-eluting stents could alter the revascularization approach for patients with diabetes and multivessel coronary artery disease . METHODS In this r and omized trial , we assigned patients with diabetes and multivessel coronary artery disease to undergo either PCI with drug-eluting stents or CABG . The patients were followed for a minimum of 2 years ( median among survivors , 3.8 years ) . All patients were prescribed currently recommended medical therapies for the control of low-density lipoprotein cholesterol , systolic blood pressure , and glycated hemoglobin . The primary outcome measure was a composite of death from any cause , nonfatal myocardial infa rct ion , or nonfatal stroke . RESULTS From 2005 through 2010 , we enrolled 1900 patients at 140 international centers . The patients ' mean age was 63.1±9.1 years , 29 % were women , and 83 % had three-vessel disease . The primary outcome occurred more frequently in the PCI group ( P=0.005 ) , with 5-year rates of 26.6 % in the PCI group and 18.7 % in the CABG group . The benefit of CABG was driven by differences in rates of both myocardial infa rct ion ( P<0.001 ) and death from any cause ( P=0.049 ) . Stroke was more frequent in the CABG group , with 5-year rates of 2.4 % in the PCI group and 5.2 % in the CABG group ( P=0.03 ) . CONCLUSIONS For patients with diabetes and advanced coronary artery disease  , CABG was superior to PCI in that it significantly reduced rates of death and myocardial infa rct ion , with a higher rate of stroke . ( Funded by the National Heart , Lung , and Blood Institute and others ; FREEDOM Clinical Trials.gov number , NCT00086450 . ) 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 % ( - 
    Output:
    
Results Compared to CCAB , it is reasonable to perform OPCAB to reduce risks of stroke [ class IIa , level of evidence ( LOE ) A ] , renal dysfunction/failure ( class IIa , LOE A ) , blood transfusion ( class I , LOE A ) , respiratory failure ( class I , LOE A ) , atrial fibrillation ( class I , LOE A ) , wound infection ( class I , LOE A ) , ventilation time , and ICU and hospital length of stay ( class I , LOE A ) .
Conclusions OPCAB compared with CCAB may improve outcomes in the short-term ( stroke , renal dysfunction , blood transfusion , respiratory failure , atrial fibrillation , wound infection , ventilation time , and length of stay ) .
However , over the longer-term , OPCAB may be associated with reduced graft patency , and increased risk of cardiac re-intervention and death