| Research BackgroundIschemic mitral regurgitation (ischaemic mitral regurgitation, IMR) is different from other original mitral valve disease, it is the complications secondary to structural abnormalities of the mitral caused by ischemic heart disease. Common to all types of clinical coronary artery disease patients, based on local and global left ventricular remodeling on pathology, The closing force and bolt tension imbalance acting on the valve leaves, Causes changes in the geometry of the mitral valve and the ventricle, Mitral valve leaflets restricted movement leaving valvular insufficiency. Although mitral regurgitation can reduce left ventricular pumping impedance and energy consumption, but because the incoming load capacity increases will lead to further expansion of the left ventricle, while increasing the ventricular wall stress can lead to pathologic remodeling intensified, so there continues to worsen cardiac function.The linkages and interactions between IMR and left ventricular remodeling makes a vicious cycle of heart failure progresses, thereby accelerating poor prognostic of refractory heart failure and death.IMR mostly occurs after acute myocardial infarction, about20%-30%of patients with ischemic cardiomyopathy merge IMR.Multiple studies have shown that the combined IMR ischemic cardiomyopathy patients morbidity and mortality is much higher than the unconsolidated IMR, if IMR is more serious, one-year survival rate can be as low as60%. Whether in patients with ischemic cardiomyopathy intervention and bypass surgery therapy, IMR is an independent risk factor in poor prognosis of cardiovascular events and death. From the pathophysiology and clinical outcomes, IMR is not only clinical complications of ischemic cardiomyopathy, become the main factors of poor prognosis and accelerate progress. IMR treatment strategies become key issues affecting ischemic cardiomyopathy clinical outcomes.Esophageal Doppler echocardiography combined with three-dimensional transthoracic Doppler echocardiography is the most commonly diagnosed tools of IMR, it can effectively define IMR generate mechanisms and guide clinical treatment strategies. And through other non-invasive imaging tools deep understand of the number and location of ischemia and myocardial viability, it is an important step in assessing prognosis of ischemic heart disease combined with IMR.Currently, there are many clinical treatment of IMR, a simple drug treatment, the treatment of ischemic myocardial revascularization, surgery based on valve repair and replacement, as well as emerging percutaneous valve repair treatment and so on. Simple drug primarily used to improve myocardial ischemia and anti-heart failure therapy; based on the ischemic cardiomyopathy treatment strategies, Revascularization is recognized as the basis of IMR treatment in order to recovery ischemic and survival myocardium; guidelines recommend in patients with moderate to severe IMR, on the basis of the revascularization in coronary artery bypass try to surgery on valve repair and valve replacement. However, so far no effective means of IMR treatment, complete coronary revascularisation, or even higher consolidation invasive valve surgery can not slow down IMR and left ventricular remodeling interactions pace.For different IMR patient populations, treatment strategies and timing choice still exists controversy,need for more large-scale randomized controlled clinical study further confirmed. This research focuses on the clinical IMR treatment strategies, through a systematic review of the relevant literature, discovery and find the main problems of IMR treatment strategies; then by meta analysis and expert consensus guidelines recommend, preliminary analysis and seek to elaborate the clinical advantages and disadvantages of the main treatment strategy in IMR;Based on the current clinical research,preliminary elaborated IMR priority treatment strategies and further clinical development direction of the pilot study.The first part Systematic review of IMR:pathophysiology, diagnosis and treatmentBackgroundSecondary or functional mitral regurgitation (IMR) is usually caused by Left ventricular dysfunction and mitral valve geometry change of Ischemic heart disease.Mitral regurgitation associated with coronary heart disease patients usually have higher morbidity and mortality rates. How the role of IMR in the occurrence and development of coronary heart disease and ischemic cardiomyopathy patients.Effects on ischemic cardiomyopathy heart failure and Clinical diagnosis and treatment strategies become another hot issue in ischemic cardiomyopathy clinical studies.Objectivesystematic review of the literature, a preliminary understanding of the epidemiology of IMR, the pathophysiology of disease, commonly used in clinical diagnosis and evaluation methods, Popular clinical treatment strategies circumstances, in order to find the controversy and blind of the IMR treatment strategies.Methods:1In accordance with cochrane systematic review pre-established requirements to develop detailed inclusion and exclusion criteria.2Develop a comprehensive and systematic search strategy based on the set standards.We searched OVID, MEDLINE, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials and other databases, manually retrieve essays on heart disease in the internationally important conference, included clinical experimental research about clinical medicine and surgical treatment effectiveness of IMR before december2013.Give a comprehensive overview of the IMR epidemiological situation, the pathophysiology of disease, commonly used in clinical diagnosis and evaluation methods,clinical currently popular treatment strategies.Conclusion 1Secondary or functional mitral regurgitation (IMR) is usually caused by ischemic heart disease and mitral valve disorders caused by changes in geometry.Mitral regurgitation associated with coronary heart disease patients usually have higher morbidity and mortality rates.2Coronary artery disease leading to myocardial injury or necrosis, left ventricular remodeling can lead to further expansion of the left heart, and increased left ventricular cavity caused by mitral ring expansion, leaflets and papillary muscle displacement resulted in pulling the valve leaflets activity disorders, systolic dysfunction can lead to reduced mitral tension force, which is the main reason for the development of IMR.3Transthoracic echocardiography is the first step in the clinical diagnosis of IMR, but transesophageal ultrasound and three-dimensional reconstruction can be used to better explore the disease mechanisms involved in the development and treatment strategies.Noninvasive assessment of ischemia and activity can provide important prognostic information.4IMR drug treatment primarily aimed at improving myocardial ischemia and associated myocardial contractile dysfunction, the main use of drugs are P-blockers and vasodilator drugs; percutaneous repair strategy is in the exploration stage and gained considerable effect. The patients with moderate or severe mitral regurgitation is usually recommended for coronary artery bypass revascularization, and on this basis, select valve surgical repair or replacement surgery; However even though performed reconstructive surgery, long-term prognosis of IMR still unknown.5IMR treatment strategies still have many unknown areas, for patients with moderate mitral regurgitation simply select revascularization or valve repair surgery combined restorative treatment; For patients with severe mitral regurgitation on the basis of revascularization select valve repair or valve replacement therapy. Currently how to choose these strategies lacks evidence-based medicine, Meta-analysis of the literature data line is needed to give guidance in clinical trials. The second part Meta Analysis on the effect of the mitral valve repair operation on patients with revascularization in moderate ischemic mitral regurgitation.BackgroundAccording to the literature review and the guidelines recommend that the current diagnosis of moderate IMR treatment strategies have simply revascularization and mitral valve repair surgery two treatment strategies, Meta research on the therapeutic strategy can help clear in mitral valve repair surgery IMR timing and prognosis in patients with treatment.Objectiveliterature review, effectively controlled clinical trials included were observed in moderate IMR (>=2+) patients the best treatment options.CABG in patients with moderate IMR clear revascularization surgery, based on the early and late mitral valve repair surgery on the prognosis of patients.Methods1In accordance with Cochrane systematic review with pre-established requirements to develop detailed inclusion and exclusion criteria, including the study of the characteristics, interventions, and outcomes measurement indicators.2Develop a comprehensive and systematic search strategy based on the set standards.We searched OVID, MEDLINE, EMBASE, Web of Science, Cochrane Central Register of Controlled Trials and other databases, manually retrieve essays on heart disease in the internationally important conference,included in the study combined CABG and mitral valve repair CABG surgery in December2013in front of the degree relevant randomized controlled trials in patients with IMR effectiveness.The main outcome measure was operative mortality and survival.Secondary outcome measures were postoperative NYHA class and late residual mitral regurgitation grading.3Follow the randomized controlled trial (RCT) quality evaluation criteria included trials for each treatment methodologies, rigorous evaluation.Evaluation of projects, including the random method, implementing inclusion and exclusion criteria, blinding, lost exit report random allocation concealment, intention-to-treat analysis between baseline and group similar situation and so on.In addition, by Jadad score table for each of the included trials to evaluate the overall quality.4In the strict quality evaluation, the study of the relevant data collected for data extraction.Need to extract data include:basic information patient objects (mean age, sex ratio, the foundation level NYHA heart function, mitral regurgitation grade), subjects inclusion and exclusion criteria, different type of surgery, postoperative NYHA class, late mortality, survival and late mitral regurgitation grading.Using a random effects model for data consolidation while assessing the size and heterogeneity of publication bias.Meta regression analysis to explore the use of the main sources of heterogeneity.Results1Selected nine non-randomized trials and one randomized controlled trial included patients with2,548cases, including1,549cases of CABG group, CABG combined MVS group999cases.2The current study population Meta-analysis showed that the number of combined surgical and long-term mortality in patients with no significant advantages over CABG alone (OR1.03;95%CI0.85-1.24; P=0.786);3Using a random effects model integration, combined surgical CABG surgery less than the simple forward mitral regurgitation grade (SMD=-0.98;95%CI (-1.35;-0.61); P=0.012);4Using a random effects model integration, postoperative NYHA class between the combined surgical patients undergoing CABG alone, and no significant difference (SMD=-0.32;95%CI (-0.75;0.12); p=0.001).ConclusionMost surgeons often use additional mitral valve surgery to treat moderate or severe ischemic mitral regurgitation, because it seems logical to assume that the load capacity of mitral regurgitation related damage, especially for patients with impaired left ventricular function.However, until conclusive evidence about the superiority of the emergence of this program, especially the surgical strategy of moderate mitral regurgitation should be carefully thought.The third part Meta-analysis on mitral valve repair and mitral valve replacement surgery of the patients with severe IMR.Background20%of the IMR will appear after myocardial infarction.The best surgical solution has still no agreement.No prospective randomized controlled trials to support,we carried out meta-analysis on repair and replacement.Methods:Our literature search in PubMad, EMBASE, Ovid, and Google Scholar.The key word is "IMR" and "repair and replacement."Inclusion and deletion criteria reflect the current surgical methods (subvalvular preservation, ring annuloplasty).The primary outcome of interested is the operative mortality and survival.secondary outcome is EF changes, left ventricular size, NYHA classification, reoperation rate and2+or higher mitral regurgitation recurrence rate.Results280documents,12trials met the inclusion criteria were included in the final analysis,12retrospective, non-randomized, randomized controlled trial included patients with2,667cases, of which MVP (mitral vavle repair) group of1731cases (61.9%), MVR (mitral vavle replacement) group of1028cases (38.1%). According to the study population of forest plans and quantitative results suggest that treatment programs between the two groups on hospital deaths has no significant difference. Surgery’s division in1998,surgery patients after1998OR0.69(95%CI,0.45-1.07; p=0.684), while surgical patients before1998OR0.39(95%CI,0.23-0.64; p<0.001).All results are using Z test and found no significant difference (P <0.001).A meta-analysis of long-term survival HR:There are11reported long-term survival. The study’s OR0.88(95%CI,0.67-1.16, P=0.007).Heterogeneity is moderate (I2=58.5%).Reoperation meta-analysis:OR1.46,95%CI (0.90,2.37), P=0.126..The number of patients re-operation between the two groups was not significantly different.Recurrence of mitral regurgitation:collect the cases during follow-up MR relapsed twice. Studies show in MR follow-up, MVP treatment group had a higher recurrence rate.Total OR7.96,95%CI (3.89,16.31), p<0.001.ConclusionMVP patients group than MVR patients group had lower hospital mortality, Surgery’s division in1998, after1998hospital mortality was no statistical difference between the two groups of patients.MVP group has MR higher recurrence rate. No significant differences between the two groups of long-term prognosis.The main risks facing the MVP and MVR are MR recurrence and thromboembolism.However, MVP or MVR therapy should be individualized considering about recurrence and risk of thromboembolism.ConclusionThis research focuses on the clinical IMR treatment strategies, through a systematic review of the relevant literature, discovery and find the main problems of IMR treatment strategies; then by meta analysis and expert consensus guidelines recommend, preliminary analysis and seek to elaborate the clinical advantages and disadvantages of the main treatment strategy in IMR;Based on the current clinical research,preliminary elaborated IMR priority treatment strategies and further clinical development direction of the pilot study. |
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