Significant Ischemic Mitral Regurgitation Research Articles

Clip It or Let It: The Efficacy of Mitral Valve Transcatheter Edge-to-Edge Repair Versus Conservative Treatment in Reducing Mortality Among Patients With Ischemic Mitral Regurgitation

BACKGROUND: Despite revascularization and optimal medial therapy (OMT) residual ischemic mitral regurgitation (IMR) continues in a self-aggravating vicious cycle to affect prognosis and survival adversely. Mitral valve surgery in combination with coronary artery bypass graft remains a subject of debate due to the absence of a net overall benefit. Mitral valve transcatheter edge-to-edge repair (M-TEER) has been gaining grounds as a viable option from observational studies, but results from randomized controlled trials (RCTs) have yielded mixed results. Thus, this study was conducted to determine whether the current collective data support the efficacy of M-TEER with OMT versus OMT alone in patients with clinically significant IMR. METHODS: A literature search from PubMed/MEDLINE, Cochrane Review Central, Clinical Trials Registry, ResearchGate, Mendeley, and Google Scholar for relevant RCTs and observational studies was conducted and reviewed independently by three reviewers. Published and unpublished studies indexed from inception until 2023 were included. The pooled estimates for the primary outcome of all-cause mortality and secondary outcomes of cardiac mortality and heart failure hospitalizations were measured using R Studio statistical software (R Foundation forStatistical Computing, Vienna, Austria). RESULTS: Seven eligible studies (five observational and two RCTs) allocated 1610 IMR patients to M-TEER + OMT (n = 942) or OMT alone (n = 668). The effect estimate using random-effects model demonstrated M-TEER with OMT to significantly reduce 1-year (odds ratio [OR], 0.67; 95% confidence interval [CI], 0.52–0.86; P = 0.002) and 2-year (OR, 0.50; 95% CI, 0.38–0.67; P < 0.00001) all-cause mortality. Cardiac mortality (OR, 0.58; 95% CI, 0.27–1.23; P = 0.15) and heart failure hospitalization (OR, 0.45; 95% CI, 0.18–1.13; P = 0.09) did not reach statistical significance between the treatment arms. CONCLUSION: In patients with IMR, M-TEER on top of OMT was able to afford a 2-year allcause mortality advantage. KEYWORDS: ischemic mitral regurgitation, mitral valve transcatheter edge-to-edge repair, optimal medical therapy

NSTEMI and Ischemic Mitral Regurgitation: Incidence and Long-Term Clinical Outcomes with Respect to Management Strategy.

The optimal treatment for ischemic mitral regurgitation (IMR) in patients of non-ST elevation myocardial infarction (NSTEMI) is a debated topic. To evaluate the long term outcome on patients with NSTEMI and IMR, particularly emphasizing the comparison of treatments in those with moderate to severe MR. We enrolled patients with NSTEMI and classified non/trivial to mild regurgitation as insignificant IMR and moderate to severe regurgitation as significant IMR. Furthermore, patients with substantial IMR were assessed for long-term clinical outcomes with respect to different management strategies. A test was considered statistically significant based on the probability value p<0.05. From a total of 4,189 patients of NSTEMI, significant IMR was found in 7.21% of patients. A significantly higher number of patients with death (1.21% vs. 13.24%, p<0.0001), cardiogenic shock (0.46% vs. 13.24%, p<0.0001) and heart failure (1.03% vs. 11.59%, p<0.0001) were found during hospitalization in patients with significant IMR. At a 2-year follow-up, a higher event rate was observed in the significant IMR group. Patients with significant IMR re-vascularized either by percutaneous coronary intervention (PCI), coronary artery bypass grafting (CABG), or CABG+ mitral valve (MV) surgery showed substantial improvement in MR grade ( 32.65% vs. 6% vs. 16.98%, p<0.0001) and LVEF (27.55% vs. 1% vs. 1.89%, p<0.0001) at 1 year follow up and significantly improved outcomes were identified compared to refused revascularization and medical management group with (-5.10% vs. 15% vs. 13.21%, p=0.04) mortality, (-33.67% vs. 61% vs. 73.58%, p<0.0001) readmission, and (-15.31% vs. 27% vs. 33.96%, p=0.01) heart failure at 2 years follow up. Higher mortality and admission rates were observed in patients with significant IMR compared to those with in-significant IMR. Notably, significant IMR patients who underwent PCI, CABG, or CABG+MV surgery showed improved outcomes compared to non-revascularized counterparts.

Abstract 10337: Early Adaptation of the Mitral Valve After St-Elevation Myocardial Infarction

Introduction: Ischemic mitral regurgitation (IMR) is associated with worse outcomes and higher mortality after myocardial infarction (MI). Clinical observations and experimental data have shown that mitral valve leaflets have the potential to enlarge over time to compensate left ventricular remodeling and prevent IMR. Previous animal studies have demonstrated that MI is associated with fibrotic changes in the mitral valve leaflets and prevent this adaptive compensation. However, the timing of mitral valve geometric changes are not well described. While previous data shows an increase in leaflet size at 6 and 12 months after MI, its short-term evolution after an ischemic event is not well documented. Methods: Twenty-two patients with ST-elevation myocardial infarction and initial left ventricular ejection fraction ≤ 45% were enrolled in Quebec Heart and Lung Institute. Participants had 3D transthoracic echocardiography (TTE) at baseline and 3 months, as well as cardiac magnetic resonance (CMR) at 3-month follow-up. Mitral valve leaflet size was measured from the 3D TTE using a custom software (Omni4D). CMR was used to derive left ventricular volumes, function and mitral regurgitant volume. Significant IMR was defined as a mitral regurgitant fraction ≥ 15% derived from the 3-month CMR. Results: Twenty-one of the 22 patients completed the imaging follow-up. Left ventricular ejection fraction at 3 months was 53 ± 10% (range from 37 to 69%). Eight patients (38%) had mild IMR at 3 months. Mitral valve surface area was significantly increased at 3 months compared with baseline for patients without IMR (10.96 ± 1.78 cm 2 vs 9.51 ± 1.62 cm 2 ; p = 0.001). Valve enlargement vs baseline was significantly greater in patients without IMR (+17 ± 13% vs -5 ± 4% for those with IMR at follow-up, p=0.0007). Conclusions: Mitral valvular surface increases within the first few months after MI, but not in all patients. Adequate valve enlargement seems related to the absence of IMR at 3 months.

Stress Echocardiography Protocol for Deciding Type of Surgery in Ischemic Mitral Regurgitation: Predictors of Mitral Regurgitation Recurrence following CABG Alone.

Purpose: Although coronary artery bypass grafting alone (CABGa), or, with mitral annuloplasty (CABGmp), is considered the best therapeutic strategy for patients with ischemic mitral regurgitation (IMR), some recurrences are still reported. The aim of this study was to evaluate the use of the mitral deformation indices (MDI) as a predictor of recurrence of mitral regurgitation in a 12-month follow-up after CABG alone. Methods: A total of 145 patients after myocardial infarction with significant IMR, eligible for CABG, were prospectively enrolled in the study. Mitral valve morphology, left ventricle function, IMR degree as assessed by effective regurgitation orifice area (ERO), myocardial viability, and MDI were assessed prior to surgery. Patients were referred for CABGa (gr.1; n = 90) or CABGmp (gr.2; n = 55) based on clinical assessment, and the results of rest and stress echocardiography (exercise echocardiography and low dose dobutamine echocardiography-DBX). One year after surgery, each patient underwent the evaluation of cardiovascular events. Univariable logistic regression analysis was used to identify the factors of recurrence of IMR in 1 year follow-up. Serial echo examinations were performed in all patients at discharge, and at 1 and 12 months after surgery. Results: Logistic regression analysis revealed that in CABGa, group preoperative changes of tenting area (TA) and coaptation high (CH) during DBX remained the predictors of the recurrence of IMR in 12 months follow-up. TAdbx > 1 cm2 provided a sensitivity of 90% and specificity of 29%, (AUC 0.6436). The best cut-off value for CHdbx was 0.4 cm (sensitivity 90%, specificity 34%; AUC 0.6432). In both groups (CABGa vs. CABGmp) no significant differences were observed in 12-month mortality (1.2% vs. 0%; p = 1.0), hospitalizations due to the heart failure (HF) exacerbation (5.9% vs. 8.5%; p = 0.72), and in the incidence of the composite endpoint (deaths/CV hosp/stroke) (7% vs. 8.5%; p = 0.742). Conclusions: The preoperative assessment of MDI changes during dbx can be used to identify patients with IMR qualified to CABG alone at increased risk of recurrence of IMR in 1 year follow-up. Mitral deformation analysis should be used for a better qualification of patients with IMR to the exact surgical approach.

Development of a Reproducible Swine Model of Chronic Ischemic Mitral Regurgitation: Lessons Learned

Durability of mitral valve repair for ischemic mitral regurgitation (IMR) remains poor. We established a swine model of chronic IMR, and describe the methods and lessons learned from this model. Thirty-five swine underwent percutaneous myocardial infarction with ethanol ablation of the circumflex or obtuse marginal (OM) arteries. Swine were followed with routine echocardiography for the development of severe IMR. Once severe IMR was established, swine underwent mitral valve operations on cardiopulmonary bypass. After operation, swine were survived up to 7 weeks. Angiographic and echocardiographic features of swine who developed severe IMR (IMR swine) and those who did not (non-IMR swine) were compared. The median number of OM arteries was 3, with2 OM arteries infarcted. Acute survival after the myocardial infarction was 74% (26 of 35) with 3 (9%) early,postoperative deaths. Among the 23 swine with follow-up todetermine IMR status, 14 of 23 (61%) developed significant IMR. Among IMR pigs, left ventricular (LV) ejection fraction decreased from 65% pre-myocardial infarction to 45% pre-mitral valve intervention (P < .001). Among non-IMR swine, LV ejection fraction decreased nonsignificantly from baseline (60%) to latest follow-up (55%) (P= .443). LV end-diastolic dimension (P= .039), wall motion score (P= .027), global circumferential strain (P= .014), and global longitudinal strain (P= .023) were significantly worse in IMR compared with non-IMR swine. A reproducible percutaneous model ofsevere IMR in swine is feasible with a guided anesthetic and perioperative approach. This model canserve as a platform to better understand the mechanism of IMR and subsequently to test novel repair techniques.

P325 Inadequate inhibition of platelet function after exercise in patients with ischemic mitral regurgitation qualified for cardiosurgery treatment

Abstract Purpose Human platelets play a major role in the pathophysiology of cardiovascular diseases. The aim of our study was to determine the relationship between exercise and level of platelet inhibition in patients (pts) after myocardial infarction (MI) with at least moderate ischemic mitral regurgitation (IMR) qualified for cardiosurgical treatment - coronary artery bypass grafting alone (CABG) or CABG with mitral reconstruction (CABGmr). Methods We collected venous blood samples from 70 pts (M 41, 66 ± 9 years) with at least moderate IMR, 3-24 weeks after MI. Platelet reactivity was estimated with the use of rapid, point-of-care platelet analyzer as the time for flowing whole blood to occlude a collagen-epinephrine ring, with shorter closure times (CEPI-CT), indicating greater activity. CEPI-CT was evaluated before (CEPI-CT rest) and 20 min after ExE (CEPI-CT ExE). Inadequate inhibition of the TXA2-dependent activation pathway was defined as CEPI-CT &amp;lt; 193 seconds. All the patients received 75-100 mg of aspirin daily (without clopidogrel treatment). Effective regurgitation orifice (ERO) was used for quantitative IMR assessment (moderate ≥10-20, severe ≥ 20 mm²). In all pts symptom-limited echocardiography (echo) semi-supine exercise test (ExE) was performed with Schiller system. All the pts were referred for CABG (multivessel coronary disease, ejection fraction (EF) 42,6 ± 10,1%, wall motion score index (WMSI) 1.65 ± 0.36). Results We observed inadequate platelet in 26 (37%) pts at rest (CEPI-CT &amp;lt; 193 sec., despite regular aspirin therapy) and in 48 (68%) pts in 20 min. after exercise. We observed a significant decrease in CEPI–CT in all analyzed group (rest vs exe: 202 sec. vs 124 sec., respectively; p &amp;lt; 0,0001) and also in pts with moderate IMR as well as with severe IMR. We didn’t observe a significant change in platelet count and mean platelet volume (MPV) between rest and exercise. Conclusions: 1. Inadequate antiplatelet effect of aspirin at rest was observed in 37% pts after MI with IMR. 2. Symptoms limited exercise test has revealed inadequate platelet inhibition (TXA2 –dependent activation pathway) in 68% of patients after MI with IMR. 3. Aspirin may have a limited antithrombotic effect after physical exercise in patients after MI with significant IMR.

P1786 Impact of exercise on platelet activity in patients with significant ischemic mitral regurgitation qualified for cardiosurgery treatment

Abstract Purpose Platelet activity is believed to play an important role in patients (pts)after myocardial infarction (MI). This study sought to examine a change in platelet activity after 2D echocardiography semi-supine exercise test (ExE) in pts with at least moderate ischemic mitral regurgitation (IMR) qualified for cardiosurgical treatment - coronary artery bypass grafting alone (CABG) or CABG with mitral reconstruction (CABGmr). Methods We collected venous blood samples from 70 patients (M 41, 66 ± 9 years) with at least moderate IMR, 3-24 weeks after MI. Platelet activity was estimated with the use of rapid, point-of-care platelet analyzer as the time (in seconds) for flowing whole blood to occlude a collagen-epinephrine ring, with shorter closure times, indicating greater activity (CEPI-CT- for assessing the thromboxane A2 –dependent activation pathway). CEPI-CT was evaluated before (CEPI-CT rest) and 20 min after ExE (CEPI-CT ExE). All the patients received 75-100 mg of aspirin daily (without clopidogrel treatment). Effective regurgitation orifice (ERO) was used for quantitative IMR assessment (moderate ≥10-20, severe ≥ 20 mm²). All the pts were referred for CABG (multivessel coronary disease, ejection fraction (EF) 42,6 ± 10,1%, wall motion score index (WMSI) 1.65 ± 0.36). Results We observed a significant decrease in CEPI–CT’s in all analyzed group (rest vs exe: 202 sec vs 124 sec, respectively; p &amp;lt; 0,0001) and in pts with moderate IMR as well as in pts with severe IMR, despite aspirin treatment. The results of the analysis of CEPI-CT and IMR size at rest and after ExE in both groups of pts are shown in Table 1. A negative correlation was found between CEPI-CT ExE and ERO ExE (r=-0,752, p = 0,0042). Conclusions 1. Significant increase in platelet activity after exercise was observed in patients after MI with IMR qualified for cardiosurgical treatment. 2. The increase in platelet activity after exercise is correlated with exercise changes of IMR size. 3. Aspirin may have a limited antithrombotic effect after physical exercise in patients after MI with significant IMR. Table 1. CEPI-CT rest CEPI-CT ExE p ERO rest ERO exe p All 202 124 &amp;lt; 0,0001 17 22 &amp;lt;0,001 Moderate IMR 201 124 0,0001 15 20 &amp;lt; 0,0001 Severe IMR 235,5 123,5 &amp;lt; 0,0001 25 31 &amp;lt; 0,0001

Prognostic Impact of Ischemic Mitral Regurgitation Severity and Myocardial Infarct Quantification by Cardiovascular Magnetic Resonance

ObjectivesThis study sought to evaluate the role of cardiac magnetic resonance (CMR) for the quantification of ischemic mitral regurgitation (IMR) and myocardial infarct size (MIS) in patients with ischemic cardiomyopathy (ICM). This study also sought to explore the interaction between IMR severity and MIS and its association with outcomes in patients with ICM. BackgroundIMR occurs secondary to a disease of the left ventricle and is associated with poor outcomes. The role of CMR for the evaluation and risk stratification of patients with ICM and IMR remains uncertain. MethodsConsecutive patients with ICM who underwent baseline CMR were included. MIS was quantified on late gadolinium enhancement imaging as the proportion of left ventricular mass. IMR was quantified with CMR by calculating the mitral regurgitant fraction (MRFraction). Cox proportional hazards models were built to assess the association of IMR and MIS quantification with the combined endpoint of all-cause death or heart transplant. ResultsWe evaluated 578 patients (mean age: 62 ± 11 years, 76% males). The mean left ventricular ejection fraction was 25 ± 11%, with an MIS of 24 ± 16% and MRFraction of 18 ± 17%. Over a median follow-up time of 4.9 years, 198 (34%) patients experienced death or cardiac transplant. On multivariable analysis, after comprehensive medical risk score, subsequent revascularization, implantable cardioverter-defibrillator insertion, and surgical mitral valve intervention were controlled for, the interaction of IMR severity and MIS emerged as a powerful predictor of adverse outcomes (p = 0.008). For patients with significant IMR (MRFraction: ≥35%), the hazard ratio comparing moderate MIS (15% to 29%) versus small MIS (<15%) was 1.51 (0.57 to 3.98), and the hazard ratio comparing large MIS (≥30%) versus small MIS was 5.41 (2.34 to 12.7). ConclusionsRisk associated with IMR is more comprehensively described as an interaction between IMR severity and MIS. Further studies in patients IMR using comprehensive CMR evaluation are needed to verify whether this approach can improve patient selection and procedural outcomes to address IMR.

Effect of Significant Ischemic Mitral Regurgitation on the Outcome of ST Segment Elevation Myocardial Infarction Patients Treated With Primary Percutaneous Coronary Intervention

Effect of Significant Ischemic Mitral Regurgitation on the Outcome of ST Segment Elevation Myocardial Infarction Patients Treated With Primary Percutaneous Coronary Intervention

Algorithms for formal stratification of patients with ischemic mitral regurgitation

Introduction: There is a significant percentage of Bulgarians suffering from ischemic heart disease (IHD) and its complications, such as ischemic mitral regurgitation (IMR). It plays an important role in Bulgarian society. Surgical treatment of this pathological conditions could have positive impact on life expectancy and the medical quality of life of patients. Aim: The purpose of the study is to establish a reproducible algorithm to advise the appropriate surgical treatment of patients with IHD and significant, but not severe IMR based on their condition. Materials and Methods: The study is based on the data collected prospectively at the Department of Cardiac Surgery, St. Marina University Hospital in Varna, Bulgaria. IHD and significant IMR (i.e. more than mild 1+, but less than severe 4+ degree) were diagnosed in 186 patients. Applying inclusion and exclusion criteria, 140 patients with pure secondary IMR remained in the study group. The data was analyzed in a retrospective fashion. We discussed two possible treatment strategies: coronary artery bypass grafting + mitral valve repair (CABG+MVRep) and isolated revascularization (CABG only). To obtain comparable data for those treatment strategies, we needed a formal stratification of the patients, allowing comparison between the groups. Results: Creating formal algorithms we are able to divide the patients into comparable Group A (CABG+MVRep) and Group B (CABG only), and surgical strategy is based on characteristics of the individual pathology of every patient. Discussion : Despite data from small randomized and non-randomized trials, to date there is no clear agreement and strategy regarding concomitant mitral valve repair with CABG during the first-time operation Conclusion: Formal stratification with the algorithms created and applied gave us the opportunity for reliable comparison of relatively different patients, and to draw conclusion for the practice. This approach should be applied in such small non-randomized trials to achieve better understanding of the problem of secondary IMR.

Additional mitral valve procedure and coronary artery bypass grafting versus isolated coronary artery bypass grafting in the management of significant functional ischemic mitral regurgitation: a meta-analysis

Functional ischemic mitral regurgitation (IMR) is commonly present following acute myocardial infarction (AMI) and tightly associated with a poorer prognosis. The optimal surgical strategy for the management of significant IMR (≥2+ grade) remains controversial and mitral valve surgery (MVS) at the time of coronary artery bypass grafting (CABG) is still debated. The primary objective of this meta-analysis was to clarify the effects of additional MVS on the prognosis in the patients with significant IMR, compared with isolated CABG. A meta-analysis of eligible studies, reporting concomitant MVS and CABG in comparison with CABG alone in respects to in-hospital mortality, survival and postoperative residual mitral regurgitation (MR) and cardiac functional status, was carried out. The outcomes of interest included in-hospital mortality, one-, three- and five-year survival and postoperative New York Heart Association (NYHA) class, residual MR and left ventricular ejection fraction (LVEF). Pooling 2 randomized controlled trials (RCTs) (N.=175) and 11 observational studies (N.=2661) demonstrated that additional MVS did not significantly influence in-hospital mortality (odds ratio [OR]=1.45, 95% confidence interval [CI] 0.93-2.28, P=0.10) and one- (OR=0.89, 95%CI 0.68-1.15, P=0.37), three- (OR=1.10, 95%CI 0.79-1.55, P=0.56) and five- (OR=0.93, 95%CI 0.73-1.18, P=0.55) year survival in comparison with isolated CABG. And pooling neither RCTs nor observational studies alone presented any evidence of significant difference in in-hospital mortality and survival between the two groups. Additionally, concomitant MVS was associated with increased postoperative LVEF (standard mean differences [SMD]=0.28, 95%CI 0.10-0.46, P<0.01) and decreased postoperative residual MR (SMD=-4.22, 95%CI -6.48 to -1.97, P<0.0001). Similar outcomes were obtained when either RCTs or observational studies were pooled alone. Additional MVS appeared to decrease postoperative NYHA functional class (SMD=-0.48, 95%CI -0.97-0.00, P=0.05) with evident heterogeneity (I2=87.5%, P<0.0001). In the subgroup analysis, MVS significantly reduced postoperative NYHA functional class in RCTs (SMD=-1.32, 95%CI -1.67 to -0.97, P<0.0001) whereas it did not among observational studies (SMD=-0.08, 95%CI -0.27-0.11, P=0.42), and heterogeneity was completely eliminated (for RCTs, I2=0%, P=0.49; for observational studies, I2=0%, P=0.40). Concomitant MVS at the time of CABG is associated with greater improvement in postoperative residual MR and LVEF in the patients with significant IMR. However, the evidence is still lacking of advantages of combined surgery over CABG alone regarding in-hospital mortality, survival and postoperative NYHA function class. Additional RCTs are needed to assess the safety and efficacy outcomes of adding mitral valve procedure in the surgical intervention of significant IMR.

Abstract 9480: Persistent MR Reduction With Stabilization of LV Remodeling and Following Chronic Polymer-Mesh Device on Infarcted Myocardium in a Chronic Ischemic MR Model

Background: Mitral valve repair with ring annuloplasty for ischemic mitral regurgitation (IMR) is associated with significant recurrent IMR due to continued left ventricular (LV) remodeling as it does not directly address LV and mitral valve tethering. We aimed to assess chronic implantation of novel polymer based mesh device to reduce IMR reduction and reverse LV remodeling. Methods: Five Dorset sheep underwent ligation of second and third circumflex obtuse marginal branches to produce chronic IMR after 8 weeks. Poly-mesh was attached to the infarcted myocardium underlying the papillary muscle with a further 8 weeks follow-up. In addition, chronic IMR was produced in 5 untreated control sheep. IMR severity was assessed by 2D vena contracta width (VCW) and 3D vena contracta area (VCA). LV end-diastolic volume (EDV), end-systolic volume (ESV), ejection fraction (EF) by 2D echo and hemodynamic data were also obtained at each baseline, chronic MR, and chronic poly-mesh stages. Results: In all sheep, after poly-mesh attachment, IMR decreased and this reduction persisted over 8 weeks (VCW 0.42±0.09 to 0.08±0.12cm; VCA 0.13±0.08 to 0.05±0.08cmsq, p&lt;0.01) with significant increase in Emax (1.1±0.5 to 2.9±0.7mmHg/ml, p&lt;0.05). There were no significant changes in LVEF (45.4±6.7 vs 42.6±3.5%, p=NS). Importantly, LV EDV and ESV at chronic poly-mesh stage were reduced compared to the chronic MR stage (EDV 110±15 to 88±18ml, p&lt;0.05; ESV 61±14 to 51±12ml, p=NS) and % increases of both EDV and ESV from chronic MR to chronic poly-mesh stage were significantly lower than those of untreated control sheep (%EDV change -22±11 vs 11±10%, p&lt;0.01; %ESV change -10±14 vs 9±10%, p&lt;0.05) (FIGURE). Conclusions: Chronic follow up after polymer-mesh device attachment shows the stabilization of mitral-LV complex in a chronic IMR model, causing persistent reduction of IMR and preventing continued LV remodeling.

Can isolated annular dilatation cause significant ischemic mitral regurgitation? Another look at the causative mechanisms

This study was to investigate the mechanisms of ischemic mitral regurgitation (IMR) by using a finite element (FE) approach. IMR is a common complication of coronary artery disease; and it usually occurs due to myocardial infarction. The pathophysiological mechanisms of IMR have not been fully understood, much debate remains about the exact contribution of each mechanism to IMR. Two patient-specific FE models of normal mitral valves (MV) were reconstructed from multi-slice computed tomography scans. Different grades of IMR during its pathogenesis were created by perturbation of the normal MV geometry. Effects of annular dilatation and papillary muscle (PM) displacement (both isolated and combined) on the severity of IMR were examined. We observed greater increase in IMR (in terms of regurgitant area and coaptation length) in response to isolated annular dilatation than that caused by isolated PM displacement, while a larger PM displacement resulted in higher PM forces. Annular dilation, combined with PM displacement, was able to significantly increase the severity of IMR and PM forces. Our simulations demonstrated that isolated annular dilatation might be a more important determinant of IMR than isolated PM displacement, which could help explain the clinical observation that annular size reduction by restrictive annuloplasty is generally effective in treating IMR.

Chronic ischemic mitral regurgitation – adiagnostic and therapeutic challenge

Chronic ischemic mitral regurgitation (IMR) is a valvular disorder caused by left ventricular dysfunction due to chronic coronary artery disease. It represents a valvular consequence of left ventricular contractile dysfunction and/or pathologic remodeling that indirectly impairs appropriate closing of the mitral valve. IMR is not caused by a structural change of the mitral valve. Acute postinfarction mitral regurgitation is also differentiated from chronic IMR. Chronic IMR occurs in the chronic stage of myocardial infarction in 20–50 % of the patients; its prevalence in the population is increasing. In patients after myocardial infarction, impaired contractility and mitral regurgitation are the most important negative prognostic factors. Furthermore, regurgitation that would be considered mild in patients with organic mitral valve disease already has a negative prognostic implication in patients with IMR. Echocardiogram is the fundamental tool for diagnostic evaluation and treatment planning in patients with IMR. The key parameters that have to be assessed include left ventricular contractile dysfunction, degree of left ventricular remodeling, pathologic changes in mitral valve geometry and quantification of regurgitation severity. In some patients, significant IMR can only be identified by stress echocardiography. Although IMR has an important negative impact on prognosis, indications for treatment and best treatment options have still not been well defined. According to the European and American guidelines, significant IMR should be treated, particularly in patients who are candidates for surgical coronary artery revascularisation. However, there is still no conclusive evidence that any surgical or percutaneous treatment of IMR improves patients’ prognosis.

¿Se debe corregir la insuficiencia mitral isquémica moderada durante la cirugía coronaria?

Significant ischemic mitral regurgitation is present in 28% of patients undergoing coronary revascularization. Their presence has prognostic implications deleterious to the patient. Randomized studies to assess the benefits of simultaneous correction during revascularization are rare. MethodsFinal results of the study (RIME) are analyzed: Coronary bypass revascularization with or without mitral annuloplasty in moderate functional ischemic mitral regurgitation. Results are compared with other recent studies and implications in current indications are commented. ResultsMitral valve annuloplasty with overcorrection associated to myocardial revascularization in patients with moderate ischemic mitral regurgitation, improves functional class and left ventricular reverse remodeling. Also decreases the degree of mitral regurgitation and the levels of pro-BNP. ConclusionThe ischemic mitral regurgitation is an independent factor of poor prognosis in patients with severe coronary lesions. Proper quantification of its severity is relevant to its indication at the time of revascularization. In many cases dynamic provocative tests will be necessary.Although the answer to the question posed by the study RIME can be interpreted as inconclusive in terms of survival, it has established significantly benefits in all markers of impaired left ventricular function during the short follow-up. It support the indication of mitral repair if moderate mitral regurgitation in low-risk patients.

Repair or replace the mitral valve for severe ischemic mitral regurgitation?

Methods 870 patients (mean age, 57,9±8,3 years) from 2000 to 2012, with coronary artery diseases and significant ischemic mitral regurgitation (>2) were operated – in 787pts CABG+MV repair were performed and in 83 pts MV replacement were combined with CABG. Groups were matched by propensity score using demographics dates, co-morbidity, LV remodeling and MR grade by quantitative echocardiography. Survival (with mean follow-up 5,3 ± 1,6 years) and NYHA functional class were compared. The impact of mitral valve replacement versus repair on survival by comparing theses propensity matched subgroups was analyzed.

Impact of Severe Mitral Regurgitation on Postoperative Outcomes After Noncardiac Surgery

ObjectivePreoperative cardiac risk assessment scoring systems traditionally do not include valvular regurgitation as a criterion for adverse outcome prediction. We sought to determine the impact of significant mitral regurgitation on postoperative outcomes after planned noncardiac surgeries. MethodsPatients with significant mitral regurgitation (moderate-severe or severe) undergoing noncardiac surgery were identified using surgical and echocardiographic databases at the Cleveland Clinic. The mechanism of mitral regurgitation was identified and classified as ischemic or nonischemic. By using propensity score analysis, we obtained 4 matched controls (patients undergoing noncardiac surgery without mitral regurgitation) for each case. The primary outcome was defined as a composite of 30-day mortality, myocardial infarction, heart failure, and stroke. Secondary outcomes included 30-day mortality, myocardial infarction, heart failure, stroke, and atrial fibrillation. ResultsA total of 298 cases and 1172 controls were included in the study. The incidence of primary outcome was significantly higher among patients with mitral regurgitation (22.2%) compared with controls (16.4%, P=.02). Analysis of the secondary outcomes revealed significant differences in perioperative heart failure (odds ratio, 1.4; 95% confidence interval, 1.02-2.0) and perioperative myocardial infarction (odds ratio, 2.9; 95% confidence interval, 1.2-7.3). Of patients with mitral regurgitation, those with ischemic mitral regurgitation had significantly more events than those with nonischemic mitral regurgitation (39.2% vs 13.3%, P<.001). ConclusionsPatients undergoing noncardiac surgery with significant ischemic mitral regurgitation are at higher risk of a composite adverse postoperative outcome, including short-term mortality, heart failure, myocardial infarction, and stroke.

Quantitation of the Mitral Tetrahedron in Patients With Ischemic Heart Disease Using Real‐Time Three‐Dimensional Echocardiography to Evaluate the Geometric Determinants of Ischemic Mitral Regurgitation

Ischemic mitral regurgitation (IMR) is common in ischemic heart disease and results in poor prognosis. However, the exact mechanism of IMR has not been fully elucidated. Quantitation of the mitral tetrahedron using three-dimentianl (3D) echocardiography is capable of evaluating the geometric determinants and mechanisms of IMR. Forty patients with a history of ST-elevation myocardial infarction at least 6 months earlier were studied. Parameters of mitral deformation and global left ventricular (LV) function and shape were evaluated by 2-dimensional echocardiography. The effective regurgitant orifice (ERO) of IMR was obtained by the quantitative continuous-wave Doppler technique. Three-dimensional (3D) echocardiography was applied to assess the mitral tetrahedron. Mitral valvular tenting area (P < 0.001), mitral annular area (P = 0.032), dilation of the LV in diastole, impairment of the LV ejection fraction, and volume of the spherically shaped LV in systole were greater in patients with an ERO ≥20 mm(2) than in those with an ERO <20 mm(2). In the mitral tetrahedron, only the interpapillary muscle roots distance showed a significant difference (P = 0.004). Multivariate analysis with the logistic regression model showed the systolic mitral tenting area (odds ratio [OR]: 280.49, 95% confidence interval [CI]: 4.59-1.72 × 10(4), P = 0.007) and interpapillary muscle distance (OR: 1.50, 95% CI: 1.03-2.19, P = 0.036) to be independent factors in predicting significant IMR (ERO ≥20 mm(2)). 3D echocardiography can be effectively applied in measuring the mitral tetrahedron and evaluating the mechanism of IMR. Mitral valvular tenting and interpapillary muscle distance are 2 independent factors of significant IMR.

Assessment of Mitral Annulus (P3 Segment) Asymmetric Deformity in Myocardial Infarction with Ischemic Regurgitation by Real Time Three‐Dimensional Echocardiography

The three-dimensional (3D) saddle shape of the mitral annulus (MA) is well characterized in humans, but segmental MA deformity and regurgitation suffered after the ischemic damage of myocardial infarction (MI) is poorly understood. In this study, such changes were assessed in patients with ischemic mitral regurgitation (IMR) post-MI, using our computerized 3D echo technique. A patient cohort (n = 72) with IMR due to inferior or anterior MI and normal controls (n = 20) were enrolled for 3D MA echo studies. Sequential coordinates of MA were manually measured from each of 18 radial planes, cropped in midsystole, to generate 3D MA images. In addition, six segmental (A1, A2, A3, P1, P2, P3) parameters of MA and global features, such as circumference, area, and height, were calculated. All six segments of MA were significantly dilated in the IMR group compared with corresponding segments of normal controls. Although there were no significant intragroup differences in A1, A2, and A3 segments, a greater degree of P3 segmental MA deformity was observed only in patients following inferior MI. The MA dilatation observed in patients with IMR after MI was more pronounced in patients with anterior versus inferior MI. However, P3 segmental dilatation of MA was significantly greater in patients after inferior IM with significant IMR, corresponding with more severe asymmetric MA deformity. (Echocardiography 2012;29:42-50).

Percutaneous Versus Surgical Revascularization in Patients With Ischemic Mitral Regurgitation

The proper way of revascularization remains controversial in patients with ischemic mitral regurgitation (IMR). We sought to compare the long-term results of percutaneous coronary intervention (PCI) and surgical revascularization in IMR. From 1996 to 2008, 185 consecutive patients (132 men; age, 63 ± 9 years) with significant IMR underwent PCI (PCI group) (n=66) or coronary artery bypass graft surgery (OP group) (n=119). In the OP group, 68 (57%) patients also underwent concomitant mitral annuloplasty. Significant IMR was defined as functional MR occurring >1 week after myocardial infarction with an effective regurgitant orifice area ≥ 0.2 cm(2). During a median follow-up of 54 months, there were 2 operative mortalities, 26 cardiac deaths, and 11 heart failure hospitalizations in the OP group and 22 cardiac deaths and 10 heart failure hospitalizations in the PCI group. The survival and cardiac mortality rates were not significantly different between the 2 groups, but event-free survival rates were significantly higher in the OP group. For the 45 propensity score-matched pairs, the risk of cardiac events was significantly lower in the OP group than in the PCI group (hazard ratio, 0.499; 95% CI, 0.251 to 0.990; P=0.043). Compared with patients who underwent coronary artery bypass graft surgery alone, event-free survival rates were significantly higher in those who underwent additional mitral annuloplasty. Compared with PCI, surgical revascularization is associated with an improved long-term event-free survival, and concomitant mitral annuloplasty should be considered in patients with significant IMR.