You will be presented with a collection of medical randomized controlled trial (RCT) reports addressing a shared clinical question -- for instance, the efficacy of a medical intervention on a disease or condition. Given the titles and abstracts of these reports, your task is to generate the conclusion of the systematic review article synthesizing the key findings. Your conclusion should be a few sentences long. In your response, include only the conclusion and no other text. The RCT reports are below.



Title 1:
Mitral-valve repair versus replacement for severe ischemic mitral regurgitation.
Abstract 1:
BACKGROUND Ischemic mitral regurgitation is associated with a substantial risk of death . Practice guidelines recommend surgery for patients with a severe form of this condition but acknowledge that the supporting evidence for repair or replacement is limited . METHODS We r and omly assigned 251 patients with severe ischemic mitral regurgitation to undergo either mitral-valve repair or chordal-sparing replacement in order to evaluate efficacy and safety . The primary end point was the left ventricular end-systolic volume index ( LVESVI ) at 12 months , as assessed with the use of a Wilcoxon rank-sum test in which deaths were categorized below the lowest LVESVI rank . RESULTS At 12 months , the mean LVESVI among surviving patients was 54.6±25.0 ml per square meter of body-surface area in the repair group and 60.7±31.5 ml per square meter in the replacement group ( mean change from baseline , -6.6 and -6.8 ml per square meter , respectively ) . The rate of death was 14.3 % in the repair group and 17.6 % in the replacement group ( hazard ratio with repair , 0.79 ; 95 % confidence interval , 0.42 to 1.47 ; P=0.45 by the log-rank test ) . There was no significant between-group difference in LVESVI after adjustment for death ( z score , 1.33 ; P=0.18 ) . The rate of moderate or severe recurrence of mitral regurgitation at 12 months was higher in the repair group than in the replacement group ( 32.6 % vs. 2.3 % , P<0.001 ) . There were no significant between-group differences in the rate of a composite of major adverse cardiac or cerebrovascular events , in functional status , or in quality of life at 12 months . CONCLUSIONS We observed no significant difference in left ventricular reverse remodeling or survival at 12 months between patients who underwent mitral-valve repair  and those who underwent mitral-valve replacement . Replacement provided a more durable correction of mitral regurgitation , but there was no significant between-group difference in clinical outcomes . ( Funded by the National Institutes of Health and the Canadian Institutes of Health ; Clinical Trials.gov number , NCT00807040 . )


Title 2:
Mitral Repair versus Replacement for Ischemic Mitral Regurgitation: Comparison of Short-Term and Long-Term Survival
Abstract 2:
Background — When compared to mitral valve replacement ( MVR ) , mitral valve repair ( MVRp ) is associated with better survival in patients with organic mitral regurgitation ( MR ) . However , there is an important controversy about the type of surgical treatment that should be used in patients with ischemic MR . The objective of this study was to compare the postoperative outcome of MVRp versus MVR in patients with ischemic MR . Methods and Results — Preoperative and operative data of 370 patients with ischemic MR who underwent mitral valve surgery  were prospect ively collected and retrospectively analyzed . MVRp was performed in 50 % of patients ( n=186 ) and MVR in 50 % ( n=184 ) . Although operative mortality was significantly lower after MVRp compared to MVR ( 9.7 % versus 17.4 % ; P=0.03 ) , overall 6-year survival was not statistically different between procedures ( 73±4 % versus 67±4 % ; P=0.17 ) . After adjusting for other risk factors and propensity score , the type of procedure  ( MVRp versus MVR ) did not come out as an independent predictor of either operative ( OR , 1.5 ; 95 % CI , 0.7–2.9 ; P=0.34 ) or overall mortality ( HR , 1.2 ; 95 % CI , 0.7–1.9 ; P=0.52 ) . Conclusion — As opposed to what has been reported in patients with organic MR , the results of this study suggest that MVRp is not superior to MVR with regard to operative and overall mortality in patients with ischemic MR . These findings provide support for the realization of a r and omized trial comparing these 2 treatment modalities


Title 3:
Clinical significance of mitral regurgitation after acute myocardial infarction. Survival and Ventricular Enlargement Investigators.
Abstract 3:
BACKGROUND Mitral regurgitation ( MR ) may complicate acute myocardial infa rct ion ( MI ) . However , it is not known whether mild MR is an independent predictor of post-MI outcome . METHODS AND RESULTS The study cohort consisted of 727 Survival and Ventricular Enlargement Study patients who underwent cardiac catheterization , including left ventriculography , up to 16 days after MI . Left ventriculograms were analyzed for diastolic and systolic volumes , global left ventricular sphericity , extent of wall motion abnormality , and endocardial curvature . The presence of MR was related to the risk of developing a cardiovascular event during 3.5 years of follow-up . MR was present in 141 patients ( 19.4 % ) .  Severe ( 3 + ) MR was present in only 2 patients . Patients with MR were more likely to have a persistently occluded infa rct artery ( MR versus no MR , 27.3 % versus 15.2 % ; P=.001 ) . Although the ejection fractions were similar , MR patients had larger end-systolic and end-diastolic volumes and more spherical ventricles than patients without MR . Sphericity change from diastole to systole was also significantly reduced in MR patients . Patients with MR were more likely to experience cardiovascular mortality ( 29 % versus 12 % ; P<.001 ) , severe heart failure ( 24 % versus 16 % ; P=.0153 ) , and the combined end point of cardiovascular mortality , severe heart failure , or recurrent myocardial infa rct ion ( 47 % versus 29 % ; P<.001 ) . The presence of MR was an independent predictor of cardiovascular mortality ( relative risk , 2.00 ; 95 % CI , 1.28 to 3.04 ) . CONCLUSIONS Mild MR is an independent predictor of post-MI mortality . As such , it adds important information for risk stratification of post-MI patients


Title 4:
Mitral valve repair versus replacement in patients with ischaemic mitral regurgitation and depressed ejection fraction: risk factors for early and mid-term mortality†.
Abstract 4:
OBJECTIVES Mitral valve ( MV ) surgery for ischaemic mitral regurgitation ( IMR ) in patients with depressed left ventricular ejection fraction ( LVEF ) is associated with poor outcomes . The optimal surgical strategy for IMR in these patients remains controversial . The objective of this study was to compare the early mortality and mid-term survival of MV repair versus MV replacement in patients with IMR and depressed LVEF undergoing coronary artery bypass grafting ( CABG ) .  METHODS A retrospective , observational , cohort study was undertaken of prospect ively collected data on 126 consecutive CABG patients with IMR and LVEF < 40 % undergoing either MV repair ( n = 98 , 78 % ) or MV replacement ( n = 28 , 22 % ) between July 2002 and February 2011 . RESULTS The overall mortality rate was 7.9 % ( n = 10 ) . MV replacement was associated with a 4-fold increase in the risk of death compared with MV repair [ 17.9 % , n = 5 vs 5.1 % , n = 5 ; odds ratio ( OR ) 4.04 , 95 % confidence interval ( CI ) 1.08 - 15.1 , P = 0.04 ] . However , after adjusting for preoperative risk factors , the type of surgical procedure was not an independent risk factor for early mortality ( OR 0.1 , 95 % CI 0.01 - 31 , P = 0.7 ) . Multivariable analysis showed that preoperative LVEF ( OR 0.8 , 95 % CI 0.6 - 0.9 , P = 0.018 ) , preoperative B-type natriuretic peptide ( BNP ) levels ( OR 1.01 , 95 % CI 1 - 1.02 , P = 0.025 ) , preoperative left ventricle end-systolic diameter ( OR 0.8 , 95 % CI 0.7 - 1.0 , P = 0.05 ) and preoperative left atrial diameter ( OR 1.3 , 95 % CI 1.0 - 1.6 , P = 0.015 ) were independent risk factors of early mortality . At the median follow-up of 45 months ( interquartile range 20 - 68 months ) , the mid-term survival rate was 74 % in the MV repair group and 70 % in the MV replacement group ( P = 0.08 ) . At follow-up , predictors of worse survival were BNP levels [ hazard ratio ( HR ) 1.0 , 95 % CI 1.0 - 1.01 , P = 0.047 ] , preoperative renal failure ( HR 4.6 , 95 % CI 1.1 - 20.3 , P = 0.039 ) and preoperative atrial fibrillation ( HR 3.3 , 95 % CI 1.1 - 10 , P = 0.032 ) . CONCLUSIONS MV repair in CABG patients with IMR and depressed LVEF is not superior to MV replacement with regard to operative early mortality and mid-term survival


Title 5:
Comparison of valve annuloplasty and replacement for ischemic mitral valve incompetence.
Abstract 5:
OBJECTIVE Mitral incompetence is a chronic sequela of myocardial infa rct ion . It is caused by apical displacement and tethering of the mitral valve leaflets after myocardial infa rct ion , result ing in incomplete coaptation . The consensus is for mitral valve surgery in the presence of significant ischemic mitral regurgitation ( IMR ) . Previously , the only option was mitral valve replacement ( MVR ) with a mechanical or tissue valve . The suboptimal results obtained prompted the development of several methods of mitral valve repair . Today , the most commonly used repair is undersized annuloplasty . METHODS We conducted a retrospective nonr and omized study of all patients who underwent operation for coronary artery disease and IMR between 2000 and 2006 . The surgeon chose the surgical method used for the mitral valve procedure . The most commonly used procedures were restrictive mitral valve annuloplasty ( MVP ) and MVR with a mechanical prosthesis . We collected all pertinent preoperative , intraoperative , and early-postoperative data . We followed up with phone interviews of the patients and their relatives and with complete clinical and echocardiography examinations . RESULTS We carried out operations on 138 patients during the study period ( MVR , 52 patients ; MVP , 86 patients ) . The 2 groups had comparable demographic data and risk factors . The 2 groups were significantly different with respect to mean ( + /-SD ) New York Heart Association ( NYHA ) class ( MVP , 2.72 + /- 0.62 ; MVR , 2.48 + /- 0.70 ; P < .01 ) and ejection fraction ( MVP , 29.01 % + /- 11.00 % ; MVR , 35.87 % + /- 11.00 % ; P < /= .01 ) . The 30-day mortality rates for the MVR and MVP groups were significantly different ( 9.61 % and 5.81 % , respectively ; P < .01 ) . Our follow-up included 83 % of the patients and continued for up to 84 months . The 2 groups showed no significant difference in mortality by the end of follow-up ; however , the MVR patients had a better ejection fraction ( 37.79 % versus 29.86 % ) and NYHA functional class ( 1.88 + /- 0.498 versus 2.36 + /- 0.564 ; P < .01 ) . CONCLUSION Correcting chronic IMR with either repair or replacement produces a good mid-term survival rate ( approximately 75 % ) for survivors in NYHA classes I and II . In our study , mortality rates for the MVP and MVR groups were similar , even though the repair group had a lower mean ejection fraction and a higher NYHA class before and after the operation . We therefore conclude that repair is superior to replacement in treating ischemic mitral insufficiency . A prospect i ve r and omized study is needed to better compare these 2 approaches
Although MVR for ischaemic MR has a higher 30-day mortality rate compared with MVRp , MVRp is associated with the higher rate of MR recurrence and the need for reoperation .
MVR remains an attractive option for ischaemic MR