***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 — For patients with ischemic mitral regurgitation ( MR ) , it is not clear whether adjunctive mitral valve ( MV ) repair at the time of coronary artery bypass graft surgery ( CABG ) is beneficial . We sought to test the hypothesis that MV repair with CABG is superior to CABG alone in improving MR without increasing operative or long-term mortality . Methods and Results — A total of 107 consecutive patients with moderate or severe ischemic MR , as determined by preoperative echocardiography , underwent CABG with concomitant MV repair ( repair group , n=50 ) or CABG only ( CABG group , n=57 ) . Degree of MR was grade d as none , mild , moderate , or severe by the proximal isovelocity surface area method . The groups were similar with respect to age , gender , baseline New York Heart Association class , ejection fraction , and number of bypass grafts . The repair group had a higher percentage of  patients with atrial fibrillation or severe MR  than the CABG group . The operative mortality was significantly higher for the repair group ( 12 % ) than the CABG group ( 2 % ) , whereas the 5-year actuarial survival rate of the 2 groups was similar ( 88%±5 % versus 87%±6 % ) . On multivariate logistic regression analysis , older age , higher New York Heart Association class , and atrial fibrillation were independent predictors of operative mortality ( P<0.05 ) . Among patients with severe MR , ischemic MR was improved in all patients of the repair group and in 67 % of patients in the CABG group ( P<0.001 ) , whereas improvement rates in patients with moderate MR were similar in the 2 groups ( 75 % versus 67 % , P = NS ) . Conclusions — Although MV repair appears to be more effective at reducing ischemic functional MR , CABG alone may be a preferable treatment option for patients with moderate MR and high operative risk factors such as old age or atrial fibrillation Background —The optimal management of moderate ( 3 + on a scale of 0 to 4 + ) ischemic mitral regurgitation ( MR ) remains controversial . Some advocate CABG alone , whereas others favor concomitant mitral annuloplasty . To clarify the optimal management of these patients , we evaluated the early impact of isolated CABG on moderate ischemic MR . Methods and Results —Between January 1992 and August 1999 , 136 patients ( 54 % male , mean age 70.5 years , mean New York Heart Association class 2.7 , mean ejection fraction 38.1 % ) with a preoperative diagnosis of moderate ischemic MR , without leaflet prolapse or pathology , underwent isolated CABG .  Thirty-eight ( 28 % ) of 136 patients had intraoperative transesophageal echocardiography ( TEE ) before CABG , and 68 ( 50 % ) had postoperative transthoracic echocardiography ( TTE ) within 6 weeks of surgery . The subgroups of patients undergoing intraoperative TEE and postoperative TTE had preoperative characteristics similar to the overall group . The 30-day operative mortality was 2.9 % ( 4/136 ) . Intraoperative TEE down grade d the severity of MR to mild or less ( 0 to 2 + ) in 89 % ( 34/38 ) . On postoperative TTE , 40 % ( 27/68 ) continued to have at least moderate MR ( 3 to 4 + ) , 51 % ( 35/68 ) improved somewhat to mild ( 2 + ) MR , and only 9 % ( 6/68 ) had resolution of their MR ( 0 to 1 + ) . The mean preoperative , intraoperative , and postoperative MR grade s were 3.0±0.0 , 1.4±1.0 , and 2.3±0.8 , respectively ( P < 0.001 ) . Conclusions —CABG alone for moderate ischemic MR leaves many patients with significant residual MR and may not be the optimal therapy for most patients . Intraoperative TEE may significantly underestimate the severity of ischemic MR . A preoperative diagnosis of moderate MR may warrant concomitant mitral annuloplasty OBJECTIVE To investigate mitral regurgitation occurring early in the course of acute myocardial infa rct ion with respect to its incidence , the impact of infa rct size and location , the accuracy of clinical detection , the contribution of global and regional left ventricular performance , and its influence on prognosis . DESIGN Prospect i ve observational study derived from patients entering Phase I of the Thrombolysis in Myocardial Infa rct ion ( TIMI ) trial . SETTING Multicenter trial involving 13 university-affiliated medical centers . PATIENTS A total of 206 patients studied within 7 hours of symptom onset during their first myocardial infa rct ion . MEASUREMENTS  Contrast left ventriculography  was used to document mitral regurgitation . RESULTS Mitral regurgitation was present in 27 patients ( 13 % ) . Although the presence of regurgitation correlated with the site of infa rct ion ( 20 of 27 had anterior infa rct ions ) and the number of akinetic chords , it was not statistically related to the peak creatine kinase value or to left ventricular chamber size or filling pressure . A murmur of mitral regurgitation was heard in only 2 patients ( 1 incorrectly ) . The presence of early mitral regurgitation predicted cardiovascular mortality at 1 year by univariate ( relative risk , 12.2 ; 95 % Cl , 3.5 to 42 ; P less than 0.0001 ) and multivariate ( relative risk , 7.5 ; Cl , 2.0 to 28.6 ; P = 0.0008 ) analyses . CONCLUSIONS Mitral regurgitation in early myocardial infa rct ion is generally clinical ly " silent , " is more common in anterior infa rct ion , is associated with regional dysfunction but not early ventricular dilation or peak enzyme release , and is an important predictor of cardiovascular mortality Background — Whether mitral valve repair during coronary artery bypass grafting ( CABG ) improves survival in patients with ischemic mitral regurgitation ( MR ) remains unknown . Methods and Results — Patients with ejection fraction ⩽35 % and coronary artery disease amenable to CABG were r and omized at 99 sites worldwide to medical therapy with or without CABG . The decision to treat the mitral valve during CABG was left to the surgeon . The primary end point was mortality . Of 1212 r and omized patients , 435 ( 36 % ) had none/trace MR , 554 ( 46 % ) had mild MR , 181 ( 15 % ) had moderate MR , and 39 ( 3 % ) had severe MR . In the medical arm , 70 deaths ( 32 % ) occurred in patients with none/trace MR , 114 ( 44 % ) in those with mild MR , and 58 ( 50 % ) in those with moderate to severe MR . In patients with moderate to severe MR , there were 29 deaths ( 53 % ) among 55 patients r and omized to CABG who did not receive mitral surgery ( hazard ratio versus medical therapy , 1.20 ; 95 % confidence interval , 0.77–1.87 ) and 21 deaths ( 43 % ) among 49 patients who received mitral surgery ( hazard ratio versus medical therapy , 0.62 ; 95 % confidence interval , 0.35–1.08 ) . After adjustment for baseline prognostic variables , the hazard ratio for CABG with mitral surgery versus CABG alone was 0.41 ( 95 % confidence interval , 0.22–0.77 ; P=0.006 ) . Conclusion — Although these observational data suggest that adding mitral valve repair to CABG in patients with left ventricular dysfunction and moderate to severe MR may improve survival compared with CABG alone or medical therapy alone , a prospect i ve r and omized trial is necessary to confirm the validity of these observations . Clinical Trial Registration — URL : http://www . clinical trials.gov . Unique identifier : NCT00023595 BACKGROUND The development of ischemic mitral regurgitation ( MR ) after myocardial infa rct ion may impose hemodynamic load during a period of active left ventricular remodeling and promote heart failure ( HF ) . However , few data are available on the relationship between ischemic MR and the long-term risk for HF . METHODS We prospect ively studied 1190 patients admitted for acute myocardial infa rct ion . Mitral regurgitation was assessed by echocardiography and was considered mild , moderate , and severe when the regurgitant jet area occupied less than 20 % , 20 % to 40 % , and greater than 40 % of the left atrial area , respectively . The median duration of follow-up was 24 months ( range , 6 - 48 months ) . RESULTS Mild and moderate or severe ischemic MR was present in 39.7 % and 6.3 % of patients , respectively . After adjusting for ejection fraction and clinical variables ( age , sex , Killip class , previous infa rct ion , hypertension , diabetes mellitus , anterior infa rct ion , ST-elevation infa rct ion , and coronary revascularization ) , compared with patients without MR , the hazard ratios for HF were 2.8 ( 95 % confidence interval [ CI ] , 1.8 - 4.2 ; P<.001 ) and 3.6 ( 95 % CI , 2.0 - 6.4 ; P<.001 ) in patients with mild and moderate or severe ischemic MR , respectively . The adjusted hazard ratios for death were 1.2 ( 95 % CI , 0.8 - 1.8 ; P = .43 ) and 2.0 ( 95 % CI , 1.2 - 3.4 ; P = .02 ) in patients with mild and moderate or severe MR , respectively . CONCLUSIONS There is a grade d independent association between the severity of ischemic MR and the development of HF after myocardial infa rct ion . Even mild ischemic MR is associated with an increase in the risk of HF OBJECTIVE Surgical management of moderate chronic ischemic mitral valve regurgitation is still debated . The aim of this study was to evaluate the effect of adding mitral valve repair to coronary artery bypass grafting on clinical outcomes and left ventricular remodeling in patients who underwent coronary artery bypass grafting alone versus coronary artery bypass grafting plus mitral valve repair in a r and omized trial . METHODS Between February 2003 and May 2007 , 102 patients were eligible for this study and were r and omly assigned to one of 2 groups by means of card allocation : coronary artery bypass grafting plus mitral valve repair ( CABG plus MVR group ; 48 patients , 47 % ) or coronary artery bypass grafting alone ( CABG group ; 54 patients , 53 % ) . The 2 groups were similar regarding demographics , perioperative clinical data , and outcomes . There were differences regarding cardiopulmonary bypass ( P < .0001 ) and aortic crossclamp ( P < .0001 ) times . Exercise tests were performed for all survivors to evaluate tolerance to exercise and variability on grade of mitral regurgitation and systolic pulmonary arterial pressure . The study was blinded for physicians and nurses involved in postoperative care and clinical follow-up . The mean follow-up was 32 + /- 18 months . RESULTS Overall in-hospital mortality was 3 % ( 3 patients ) . One ( 1.8 % ) patient died in the CABG group , and 2 ( 4.1 % ) patients died in the CABG plus MVR group . Survival rates + /- st and ard error at 5 years for patients in the CABG and CABG plus MVR groups were 88.8 % + /- 3.2 % and 93.7 % + /- 3.1 % , respectively . A significant difference was found between the 2 groups with regard to mean New York Heart Association class ( P < .0001 ) , left ventricular end-diastolic diameter ( P < .01 ) , left ventricular end-systolic diameter ( P < .01 ) , pulmonary arterial pressure ( P < .0001 ) , and left atrial size ( P < .01 ) . At follow-up , coronary artery bypass grafting alone was able to reduce mitral regurgitation grade in 40 % of patients , whereas in the remaining patients mitral regurgitation grade remained stable or worsened . In the CABG group , among the 17 patients with mild mitral regurgitation and 12 patients with moderate mitral regurgitation at rest , 7 ( 40 % ) and 9 ( 75 % ) patients , respectively , had worsening in mitral regurgitation grade and pulmonary artery pressure during exercise . CONCLUSIONS The efficacy of adding mitral valve repair to coronary artery bypass grafting is well demonstrated by the improvement of New York Heart Association functional class and percentage of left ventricular ejection fraction and by the decrease of mitral regurgitation grade , left ventricular end-diastolic diameter , left ventricular end-systolic diameter , pulmonary artery pressure , and left atrial size . Moreover , coronary artery bypass grafting alone left more patients with heart failure 
    Output:
    
Review of current literature showed mixed results in terms of improvement in functional status but failed to show any survival benefit of performing MVR along with CABG .