***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: 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 objective of this r and omized clinical trial of  elective coronary artery bypass grafting  was to investigate whether intraoperative mean arterial pressure below autoregulatory limits of the coronary and cerebral circulations was a principal determinant of postoperative complications . The trial compared the impact of two strategies of hemodynamic management during cardiopulmonary bypass on outcome . Patients were r and omized to a low mean arterial pressure of 50 to 60 mm Hg or a high mean arterial pressure of 80 to 100 mm Hg during cardiopulmonary bypass . METHODS A total of 248 patients undergoing primary , nonemergency coronary bypass  were r and omized to either low ( n = 124 ) or high ( n = 124 ) mean arterial pressure during cardiopulmonary bypass . The impact of the mean arterial pressure strategies on the following outcomes was assessed : mortality , cardiac morbidity , neurologic morbidity , cognitive deterioration , and changes in quality of life . All patients were observed prospect ively to 6 months after the operation . RESULTS The overall incidence of combined cardiac and neurologic complications was significantly lower in the high pressure group at 4.8 % than in the low pressure group at 12.9 % ( p = 0.026 ) . For each of the individual outcomes , the trend favored the high pressure group . At 6 months after coronary bypass for the high and low pressure groups , respectively , total mortality rate was 1.6 % versus 4.0 % , stroke rate 2.4 % versus 7.2 % , and cardiac complication rate 2.4 % versus 4.8 % . Cognitive and functional status outcomes did not differ between the groups . CONCLUSION Higher mean arterial pressures during cardiopulmonary bypass can be achieved in a technically safe manner and effectively improve outcomes after coronary bypass OBJECTIVE In a r and omized trial of 223 patients undergoing coronary artery surgery with cardiopulmonary bypass , we have reported a neuroprotective effect of mild hypothermia . To determine whether the beneficial effect of mild hypothermia was long-lasting , we repeated the psychometric tests in 131 patients after 5 years . METHODS Patients were cooled to 32 degrees C during aortic crossclamping and then r and omized to rewarming to either 34 degrees C or 37 degrees C , with no further rewarming until arrival in intensive care unit . Cognitive function was measured preoperatively and 1 week and 5 years postoperatively with a battery of 11 psychometric tests interrogating verbal memory , attention , and psychomotor speed and dexterity . RESULTS Patients who had greater cognitive decline 1 week after surgery showed poorer performance 5 years later . The magnitude of cognitive decline over 5 years was modest . The incidence of deficits defined as a 1 st and ard deviation [ SD ] decline in at least 1 of 3 factors was not different between temperature groups . Fewer patients in the hypothermic group had deficits that persisted over the 5 years , but this difference did not attain statistical significance ( RR = 0.64 , P = .16 ) . CONCLUSIONS The effect of surgery on cognitive function observed early after surgery is an important predictor of cognitive performance 5 years later . Although there was evidence of a neuroprotective effect of mild hypothermia early after surgery in the original cohort , the results after 5 years were inconclusive . In general , the magnitude of cognitive changes over 5 years was modest . We believe that further trials investigating the efficacy of mild hypothermia in patients having cardiac surgery are warranted BACKGROUND AND PURPOSE Percutaneous transluminal angioplasty ( PTA ) is currently being assessed for the treatment of carotid stenosis . In comparison with carotid endarterectomy ( CEA ) , there is evidence of an increased risk of cerebral microembolism during the procedure . We have sought evidence of any neuropsychological sequelae of carotid PTA and compared it with CEA to demonstrate the relative safety of the 2 treatment options . METHODS The neuropsychological outcomes after CEA and PTA were compared in 2 matched groups of patients with severe symptomatic carotid stenosis , 96 % of whom had been r and omized in the Carotid and Vertebral Artery Transluminal Angioplasty Study ( CAVATAS ) , at a single center .  Transcranial Doppler insonation of the middle cerebral artery was used to measure cerebral reactivity in response to carbon dioxide inhalation before treatment and then to detect microembolization of the ipsilateral cerebral hemisphere and measure changes in blood flow velocity during the procedures . The performance on a neuropsychological test battery administered before , 6 weeks after , and 6 months after the procedure was compared in 20 patients undergoing PTA and 26 having CEA .  RESULTS At 6 weeks , 5 patients in each group showed a similar decline in neuropsychological performance ; global measures showed no significant difference between the 2 procedures , despite a significantly higher incidence of microemboli during PTA . Both groups showed a marked reduction in anxiety after treatment . CONCLUSIONS The findings provide some reassurance that PTA is not associated with greater cerebral complications than CEA , despite the higher embolic load recorded by transcranial Doppler ultrasonography during angioplasty OBJECTIVE To investigate cognitive outcome after on and off pump coronary artery bypass grafting . METHODS Seventy patients between 50 and 80 years with stable angina pectoris , ejection fraction > 30 % , serum creatinine < 150 micromol/l , and lack of tight main stem stenosis were r and omized to on or off pump coronary artery bypass grafting . St and ardized neuropsychological tests evaluated attention , verbal and visuo-spatial short-term and working memory , verbal learning , delayed recall , visuo-motor speed , and aspects of executive functions . Levels of anxiety and depression were also investigated . Testing was performed before and at 1 week , 1 and 6 months after surgery . RESULTS There was no difference in cognitive impairment ( defined as a 20 % reduction in at least 20 % of the tests ) between groups . The incidence at 1 week post-operatively was 57 % in the on pump group and 58 % in the off pump group , after 1 month 30 % and 12 % and after 6 months 19 % and 15 % , respectively ( p for interaction=0.19 ) . There was no difference between groups in anxiety ( p=0.18 ) or depression ( p=0.48 ) . CONCLUSIONS This prospect i ve , r and omized study showed no differences in post-operative cognitive function after on pump compared to off pump coronary artery bypass grafting in low risk patients BACKGROUND Previously , we reported that there was no significant difference at 30 days in the rate of a primary composite outcome of death , myocardial infa rct ion , stroke , or new renal failure requiring dialysis between patients who underwent coronary-artery bypass grafting ( CABG ) performed with a beating-heart technique ( off-pump )  and those who underwent CABG performed with cardiopulmonary bypass ( on-pump ) . We now report results on quality of life and cognitive function and on clinical outcomes at 1 year . METHODS We enrolled 4752 patients with coronary artery disease who were scheduled to undergo CABG and r and omly assigned them to undergo the procedure off-pump or on-pump . Patients were enrolled at 79 centers in 19 countries . We assessed quality of life and cognitive function at discharge , at 30 days , and at 1 year and clinical outcomes at 1 year . RESULTS At 1 year , there was no significant difference in the rate of the primary composite outcome between off-pump and on-pump CABG ( 12.1 % and 13.3 % , respectively ; hazard ratio with off-pump CABG , 0.91 ; 95 % confidence interval [ CI ] , 0.77 to 1.07 ; P=0.24 ) . The rate of the primary outcome was also similar in the two groups in the period between 31 days and 1 year ( hazard ratio , 0.79 ; 95 % CI , 0.55 to 1.13 ; P=0.19 ) . The rate of repeat coronary revascularization at 1 year was 1.4 % in the off-pump group and 0.8 % in the on-pump group ( hazard ratio , 1.66 ; 95 % CI , 0.95 to 2.89 ; P=0.07 ) . There were no significant differences between the two groups at 1 year in measures of quality of life or neurocognitive function . CONCLUSIONS At 1 year after CABG , there was no significant difference between off-pump and on-pump CABG with respect to the primary composite outcome , the rate of repeat coronary revascularization , quality of life , or neurocognitive function . ( Funded by the Canadian Institutes of Health Research ; CORONARY Clinical Trials.gov number , NCT00463294 . ) Flaws in the design , conduct , analysis , and reporting of r and omised trials can cause the effect of an intervention to be underestimated or overestimated . The Cochrane Collaboration ’s tool for assessing risk of bias aims to make the process clearer and more BACKGROUND Neurologic and clinical morbidity after  coronary artery bypass grafting ( CABG )  can be significant . By avoiding cardiopulmonary bypass , off-pump CABG ( OPCAB ) may reduce morbidity . METHODS Sixty patients ( 30 CABG and 30 OPCAB ) were prospect ively r and omized . Neurocognitive testing was performed before the operation and 2 weeks and 1 year after the operation . Neurologic testing to detect stroke and (99m)Tc-HMPAO whole-brain single photon emission computed tomography scanning to assess cerebral perfusion were performed before the operation and 3 days afterward . Bilateral middle cerebral artery transcranial Doppler scanning was performed intraoperatively to detect cerebral microemboli . All examiners were blinded to treatment group . Clinical morbidity and costs were compared . RESULTS Coronary artery bypass grafting was associated with more cerebral microemboli ( 575 + /- 278.5 CABG versus 16.0 + /- 19.5 OPCAB ( median + /- semiinterquartile range ) and significantly reduced cerebral perfusion after the operation to the bilateral occipital , cerebellar , precunei , thalami , and left temporal lobes ( p < or = 0.01 ) . Cerebral perfusion with  OPCAB  was unchanged . Compared with base line , OPCAB patients performed better on the Rey Auditory Verbal Learning Test ( total and recognition scores ) at both 2 weeks and at 1 year ( p < or = 0.05 ) , whereas CABG performance was statistically unchanged for all cognitive measures . Patients who underwent CABG had more chest tube drainage ( 1389 + /- 1256 mL CABG versus 789 + /- 586 mL OPCAB , p = 0.02 ) and required more blood ( 3.9 + /- 5.8 U CABG versus 1.2 + /- 2.2 U OPCAB , p = 0.02 ) , fresh frozen plasma ( 3.0 + /- 6.0 U CABG versus 0.5 + /- 2.2 U OPCAB , p = 0.03 ) , and hours of postoperative use of dopamine ( 16.3 + /- 21.2 hours CABG versus 7.3 + /- 9.7 hours OPCAB , p = 0.04 ) . 
    Output:
    
It found that both the CABG and medical groups had small to moderate improvements in memory versus baseline at 1 year and no changes versus baseline at 6 years for all neuropsychological tests measured .
Further , there were no between-group differences at any follow-up or in change from baseline to any follow-up .