Surgical treatment of functional mitral regurgitation

Angiotensin receptor-neprilysin inhibitors and cardiac remodeling

The aim of this study was to determine how sacubitril/valsartan compared with valsartan in an outpatient setting affects left ventricular remodeling in heart failure with reduced ejection fraction and functional (or secondary) mitral regurgitation (SMR) due to the effect of dual inhibition of the renin-angiotensin system and neprilysin. The outpatient study included 90 patients with chronic SMR who were followed up for 12 months. They received sacubitril/valsartan or valsartan instead of the more commonly used angiotensin-converting enzyme inhibitor enalapril for heart failure, in addition to standard medical therapy for heart failure. The difference in NT-proBNP change between groups was the primary endpoint. Changes in effective regurgitation orifice area, left ventricular ejection fraction, left ventricular end-systolic and end-diastolic volume indices, left atrial volume index, E/e' index, and exercise tolerance on the 6-minute walk test were secondary endpoints. In the treatment efficacy analysis, NT-proBNP levels decreased significantly by 37% in the sacubitril/valsartan group and by 11% in the valsartan group (P<0.001). Ejection fraction and exercise tolerance (increase in walking distance in the 6-min test) increased in the sacubitril/valsartan group (P<0.05). Also, in this group, the effective area of the regurgitation orifice, the left atrial volume index, the E/e' index, and the indices of the end-systolic and end-diastolic volume of the left ventricle (P<0.05) decreased more pronouncedly. Compared with valsartan, treatment with sacubitril/valsartan led to a significant improvement in cardiac remodeling in patients with SMR and heart failure with reduced ejection fraction.

ECHOCARDIOGRAPHIC ASPECTS OF ASSESSMENT OF MITRAL INSUFFICIENCY IN PATIENTS WITH ACUTE MYOCARDIAL INFARCTION WITH REDUCED LEFT VENTRICULAR EJECTION FRACTION

OBJECTIVE

The aim is to analyze patients with acute myocardial infarction with reduced ejection fraction in order to determine risk factors for mitral insufficiency.

PATIENTS AND METHODS

Materials and methods: The study included 149 patients with acute myocardial infarction. Among the patients, there were 113 males (75.8%) and 36 females (24.2%). The age of the patients ranged from 43 to 86 years. Echocardiography was performed using a Phillips Epiq 7 machine. Patients were examined three times: upon admission to the hospital, after revascularization, and six months after discharge. Patients received transthoracic echocardiography, which was used to determine the presence and degree of mitral regurgitation.

RESULTS

Results: According to the results of the study, it was found that the presence of concomitant somatic pathology worsens the course of an acute myocardial infarction, in turn increasing the likelihood of valvular pathology. An increase in left ventricular volume indicators, such as end-diastolic volume, end-systolic volume, end-diastolic index, and the index of contractile function (ejection fraction) contributes to the development of mitral valve insufficiency.

CONCLUSION

Conclusions: The presence of mitral regurgitation in patients with acute myocardial infarction and reduced left ventricular ejection fraction worsens the course of the disease and negatively affects the prognosis.

Transcatheter edge-to-edge repair in patients with mitral regurgitation and cardiogenic shock: a new therapeutic target

PURPOSE OF REVIEW

Cardiogenic shock with significant mitral regurgitation portends a poor prognosis with limited therapeutic options. Herein, we review the available evidence regarding the patient characteristics, management, impact of transcatheter edge-to-edge repair (TEER) on hemodynamics, and clinical outcomes of patients with cardiogenic shock and mitral regurgitation.

RECENT FINDINGS

Several observational studies and systematic reviews have demonstrated the feasibility and safety of TEER in cardiogenic shock complicated by degenerative or functional mitral regurgitation. Surgical interventions for mitral regurgitation remain limited owing to the risk profile of patients in cardiogenic shock. TEER has been studied in both degenerative and functional mitral regurgitation and remains feasible in the critically ill population. Moreover, TEER is associated with reduction in mitral regurgitation and improvement in-hospital and long-term mortality.

SUMMARY

TEER remains a promising therapeutic option in cardiogenic shock complicated by significant mitral regurgitation, but additional research is required to identify patient and procedural characteristics, hemodynamic parameters, and the optimal time for intervention. Moreover, future randomized controlled trials are in progress to evaluate the potential benefit of TEER against medical management in cardiogenic shock and mitral regurgitation.

Transcatheter mitral valve intervention

Mitral regurgitation is a common valvular heart disorder increasing with age. Many patients are ineligible for mitral valve surgery due to their age and other comorbidities. Left untreated, patients develop severe disease with a poor prognosis. The development of lower risk percutaneous mitral valve interventions has helped meet the needs of this previously untreated patient group. This review explores the recent and more established developments that have expanded the armamentarium for transcatheter mitral valve intervention.

Modified Mitral Valve Repair with Its Insufficiency of Ischemic Genesis

The aim of the study was to assess the effectiveness of modified mitral valve repair in comparison with traditional methods of correcting ischemic mitral regurgitation.

Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

The unfinished saga of invasive procedures for secondary mitral regurgitation

Secondary mitral regurgitation (MR) is a common valvular heart disease. Its prognostic burden in patients suffering from idiopathic or ischemic cardiomyopathy (ICM) with left ventricular (LV) dysfunction/dilation has been clearly demonstrated. Severe secondary MR is associated with an increased mortality and frequent heart failure hospitalizations. Although guideline-directed medical therapy (GDMT) is the cornerstone of the management of secondary MR, a certain proportion of patients remain symptomatic. For these patients, several surgical techniques have been progressively developed during the last few decades (replacement, repair, sub-valvular apparatus interventions and other ventricular approaches). In the absence of evidence-based medicine, the benefits of these surgical procedures remains controversial, leading to a low level of recommendation in the guidelines. One way to anticipate the future is to look to the past. Recent prospective randomized trials evaluated surgical and percutaneous techniques and led to a better understanding of how best to treat this disease. In this article, we aim to describe the saga of the surgical and percutaneous treatments for secondary MR throughout the previous decades.

Restrictive mitral annuloplasty with or without coronary artery bypass grafting in ischemic mitral regurgitation

Aims

In patients with ischaemic mitral regurgitation (MR), the impact of mitral valve surgery with concomitant coronary artery bypass grafting (CABG) on post‐operative survival and left ventricular (LV) reverse remodelling remains unknown. Therefore, we investigated these outcomes following restrictive mitral annuloplasty (RMA) with and without CABG in those patients.

Methods and results

This study included 309 patients with chronic MR and ischaemic cardiomyopathy for whom concomitant CABG was indicated (n = 225) or not indicated (n = 84) with RMA. The primary endpoint was all cause mortality during the follow‐up, and the secondary endpoint was defined as the composite of mortality and re‐admission for heart failure. Linear mixed model was used to analyse serial echocardiographic changes in LV function. To reduce the impact of treatment bias and potential confounding in the direct comparisons between patients who underwent RMA with and those who underwent it without CABG, we established weighted Cox proportional‐hazards regression models with inverse‐probability‐of‐treatment weighting. Pre‐operatively, there were no intergroup differences in age (RMA with CABG, 67 ± 9 vs. RMA without CABG, 68 ± 11, P = 0.409) and logistic EuroSCORE II (16 ± 14 vs. 15 ± 15%, P = 0.496). The 30‐day mortalities were 2.7% and 3.6%, respectively (P = 0.67). During follow‐up with a mean duration of 72 ± 37 months (range, 5.6–179), there were 157 deaths and 105 re‐admissions for heart failure. Overall 1‐year and 5‐year survival rates were 83 ± 2% and 58 ± 3%, respectively. Patients who did not receive CABG with RMA had a significantly lower 5‐year survival rate (45% vs. 63%, P = 0.049) and freedom from adverse events defined as mortality and/or admission for heart failure (19% vs. 43%, P < 0.001) than those who did. After adjustments for clinical covariates with inverse‐probability‐of‐treatment weighting, concomitant CABG was identified as an independent protective factor for adverse events (hazard ratio: 0.53; 95% confidence interval: 0.44–0.64; P < 0.001). Along with significant MR reduction, LV function parameters changed over time after surgery in both groups, with greater improvements in patients who underwent RMA with CABG (time effect, P < 0.001; and interaction effect, P = 0.002).

Conclusions

RMA can be performed with an acceptable operative mortality, irrespective of indications for CABG. Patients with ischaemic MR for whom CABG is indicated with RMA are more likely to show better long‐term and event‐free survival and greater improvements in LV systolic function. The optimal revascularization strategy should be discussed with a heart team whenever indicated in patients with ischaemic MR; otherwise, they may miss the opportunity to benefit from concomitant CABG during subsequent RMA.

Left Ventricular Size Predicts Clinical Benefit After Percutaneous Mitral Valve Repair for Secondary Mitral Regurgitation: A Systematic Review and Meta-Regression Analysis

BACKGROUND

The benefit of percutaneous mitral valve repair (PMVR) in patients with secondary MR is still debated. We aimed to compare the outcome of PMVR with optimal medical therapy (OMT) versus OMT alone in patients with secondary mitral regurgitation (MR) and to assess the role of potential effect modifiers.

METHODS

We performed a systematic review and meta-analysis of 2 randomized clinical trials (RCT) and 7 non-randomized observational studies (nROS). Hazard ratios (HR) and 95% confidence intervals (CI) were pooled through inverse variance random-effects model to compute the summary effect size for all-cause death, cardiovascular death and cardiac-related hospitalization. Subgroup and meta-regression analysis were also performed.

RESULTS

An overall population of 3118 individuals (67% men; mean age, 73 years) was included: 1775 PMVR+OMT and 1343 OMT patients, with mean follow-up of 24 ± 15 months. PMVR+OMT was associated with a lower risk of all-cause death (HR: 0.77; 95% CI: 0.68-0.87), cardiovascular death (HR: 0.55; 95% CI: 0.34-0.89) and cardiac-related hospitalization (HR:0.77; 95% CI: 0.64-0.92). Meta-regression analysis showed that larger left ventricular end-diastolic volume index (LVEDVI) portends higher risk of all-cause death, cardiovascular death and cardiac-related hospitalization after PMVR (p < 0.001 for all).

CONCLUSIONS

This study-level meta-analysis shows that PMVR+OMT is associated with reduced all-cause death, cardiovascular death and cardiac-related hospitalization when compared with OMT alone in secondary MR. LVEDVI is a predictive marker of efficacy, as patients with smaller LVEDVI have been shown to derive the largest benefit from PMVR.

Minithoracotomy and Beating Heart Strategy for Mitral Surgery in Secondary Mitral Regurgitation

BACKGROUND

In patients with secondary mitral regurgitation (MR) associated with low ejection fraction or previous heart surgery, minimally invasive mitral valve surgery without aortic cross-clamp (MIMVS-WAC) has shown promising results. We report our experience for this strategy in our centers.

METHODS

Between August 2011 and April 2017, 46 patients (mean age 69 ± 11 years, 76% males) received MIMVS-WAC. Indications for this technique were prior coronary bypass surgery (26%), severe or recent left ventricular (LV) dysfunction (30%), or both (39%). The mean EuroSCORE II was 12 ± 10.

RESULTS

For each procedure, we conducted right minithoracotomy and hypothermic cardiopulmonary bypass (CPB) after peripheral cannulation. Mean CPB time was 159 ± 39 minutes. A mitral valve replacement (MVR) was performed in 23 cases (50%), an annuloplasty in 22 cases (48%), and a prosthesis pannus removal in 1 case (2%). Mean hospital length of stay was 12 ± 5.4 days. We report no sternotomy conversions, six reoperations for bleeding, and three deaths at 30 days. Transfusion was requested in 62% (mean infusion 2 ± 2.4 packed red blood cells). The postoperative echocardiography showed an LV function preservation in 69% of cases and a reduction of pulmonary arterial pressure in 73% of cases. Four additional deaths occurred in the long-term follow-up (mean 637 ± 381 days, median 593 days). No mitral reoperation was required, with a MR ≤ 2 in 90% of patients.

CONCLUSION

In high-risk patients, the MIMVS-WAC is a safe technique. It avoids hard dissections while ensuring excellent preservation of cardiac function.

Cardiovascular Outcomes Assessment of the MitraClip in Patients with Heart Failure and Secondary Mitral Regurgitation: Design and rationale of the COAPT trial

BACKGROUND

Patients with heart failure (HF) and symptomatic secondary mitral regurgitation (SMR) have a poor prognosis, with morbidity and mortality directly correlated with MR severity. Correction of isolated SMR with surgery is not well established in this population, and medical management remains the preferred approach in most patients. The Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation (COAPT) trial was designed to determine whether transcatheter mitral valve (MV) repair with the MitraClip device is safe and effective in patients with symptomatic HF and clinically significant SMR.

STUDY DESIGN

The COAPT trial is a prospective, randomized, parallel-controlled, open-label multicenter study of the MitraClip device for the treatment of moderate-to-severe (3+) or severe (4+) SMR (as verified by an independent echocardiographic core laboratory) in patients with New York Heart Association class II-IVa HF despite treatment with maximally tolerated guideline-directed medical therapy (GDMT) who have been determined by the site's local heart team as not appropriate for MV surgery. A total of 614 eligible subjects were randomized in a 1:1 ratio to MV repair with the MitraClip plus GDMT versus GDMT alone. The primary effectiveness end point is recurrent HF hospitalizations through 24 months, analyzed when the last subject completes 12-month follow-up, powered to demonstrate superiority of MitraClip therapy. The primary safety end point is a composite of device-related complications at 12 months compared to a performance goal. Follow-up is ongoing, and the principal results are expected in late 2018.

CONCLUSIONS

HF patients with clinically significant SMR who continue to be symptomatic despite optimal GDMT have limited treatment options and a poor prognosis. The randomized COAPT trial was designed to determine the safety and effectiveness of transcatheter MV repair with the MitraClip in symptomatic HF patients with moderate-to-severe or severe SMR.

Percutaneous Mitral Valve Interventions and Heart Failure

Mitral regurgitation (MR) is the most frequent Valvular Heart Disease (VHD) and is an important cause of heart failure. MR can be caused by primary valve abnormality (Degenerative MR/Primary MR) or it can be secondary to cardiomyopathy (Functional MR/Secondary MR). Medical management alleviates symptoms but does not alter the progression of the disease. Current guidelines recommend surgery for moderate-to-severe (Grade > 3) MR in patients with symptoms or evidence of left ventricular dysfunction. Despite current practice guidelines, the majority of patients with severe MR do not undergo surgery. The reasons include high surgical risk from advanced age or multiple comorbidities, and a lack of clear data supporting valve surgery for secondary MR with LV dysfunction. The recent emergence of percutaneous interventional approaches in treating MR has expanded therapeutic options for patients who are at high risk for conventional Mitral Valve (MV) surgery. In this chapter, we will review the novel advancements in the field of percutaneous MV interventions that could potentially become the standard of care for patients with MR and heart failure.

Multimodality imaging assessment of mitral valve anatomy in planning for mitral valve repair in secondary mitral regurgitation

Secondary mitral regurgitation (MR) is frequent valvular heart disease and conveys worse prognostic. Therapeutic surgical or percutaneous options are available in the context of severe symptomatic secondary MR, but the best approach to treat these patients remains unclear, given the lack of clear clinical evidence of benefit. A comprehensive evaluation of the mitral valve apparatus and the left ventricle (LV) has the ability to clearly define and characterize the disease, and thus determine the best option for the patient to improve its clinical outcomes, as well as quality of life and symptoms. The current report reviews the mitral valve (MV) anatomy, the underlying mechanisms associated with secondary MR, the related therapeutic options available, and finally the usefulness of a multimodality imaging approach for the planning of surgical or percutaneous mitral valve intervention.

Anatomical considerations of percutaneous transvenous mitral annuloplasty: a novel procedure for treatment of functional mitral regurgitation

Percutaneous transvenous mitral annuloplasty (PTMA) has evolved as a latest procedure for the treatment of functional mitral regurgitation. It reduces mitral valve annulus (MVA) size and increases valve leaflet coaptation via compression of coronary sinus (CS). Anatomical considerations for this procedure were elucidated in the present study. In 40 formalin fixed adult cadaveric human hearts, relation of the venous channel formed by CS and great cardiac vein (GCV) to MVA and the adjacent arteries was described, at 6 points by making longitudinal sections perpendicular to the plane of MVA, numbered 1-6 starting from CS ostium. CS/GCV formed a semicircular venous channel on the atrial side of MVA. Based on the distance of CS/GCV from MVA, two patterns were identified. In 37 hearts, the venous channel at point 2 was widely separated from the MVA compared to the two ends and in three hearts a nonconsistent pattern was observed. GCV crossed circumflex artery superficially. GCV or CS crossed the left marginal artery and ventricular branches of circumflex artery superficially in 17 and 23 hearts, respectively. As the venous channel was related more to the left atrial wall, PTMA devices probably exert an indirect traction on MVA. The arteries crossing deep to the venous channel may be compressed by PTMA device leading to myocardial ischemia. Knowledge of the spatial relations of MVA and a preoperative and postoperative angiogram may help to reduce such complications during PTMA.

Comparison of Percutaneous Mitral Valve Repair Versus Conservative Treatment in Severe Functional Mitral Regurgitation

Percutaneous mitral valve repair (PMVR) using the MitraClip System is feasible and entails clinical improvement even in patients with high surgical risk and severe functional mitral regurgitation (MR). The aim of this study was to assess survival rates and clinical outcome of patients with severe, functional MR treated with optimal medical therapy (OMT) compared with those who received MitraClip device. Sixty patients treated with OMT were compared with a propensity-matched cohort of 60 patients who underwent PMVR. Baseline demographics and echocardiographic variables were similar between the 2 groups. The mean age of patients was 75 years, and 67% were men. The median logistic EuroSCORE and EuroSCORE II were 17% and 6%, respectively, because of the presence of several co-morbidities. The mechanism of MR was functional in all cases with an ischemic etiology in 52% of patients. Median left ventricle ejection fraction was 34%. All the patients were symptomatic for dyspnea with 63% and 12% in the New York Heart Association class III and IV, respectively. In PMVR group, the procedure was associated with safety and very low incidence of procedural complications with no occurrence of procedural and inhospital mortality. After a median follow-up of 515 days (248 to 828 days), patients treated with PMVR demonstrated overall survival, survival freedom from cardiac death and survival free of readmission due to cardiac disease curves higher than patients treated conservatively (log-rank test p = 0.007, p = 0.002, and p = 0.04, respectively). In conclusion, PMVR offers a valid option for selected patients with high surgical risk and severe, functional MR and entails better survival outcomes compared with OMT.

Catheter-based or surgical repair of the highest risk secondary mitral regurgitation patients

Surgical mitral valve repair (MVR) remains the standard of care for patients with severe valve incompetence with clear, proven benefit for patients with primary mitral regurgitation (MR). Secondary MR is a primary disease of the left ventricular (LV) myocardium. Up to 50% of patients develop secondary MR after an acute myocardial infarction (ischemic MR), with approximately 10% of these having severe MR. It is controversial as to whether surgical MVR is beneficial for these patients because valve repair or replacement does not correct the underlying disease. The increased perioperative risk due to decreased LV function makes clinical decision-making even more complex. The recently introduced less-invasive, catheter-based therapies are potential promising solutions for this dilemma. While the MitraClip device is already in widespread clinical use as a viable therapeutic option in higher-risk patients with primary MR and currently in investigational trials for secondary MR, several other devices for both repair and replacement are currently undergoing feasibility trials. Due to the complex structure of the mitral valve, the development of transcatheter mitral valve replacement has been much slower than that of transcatheter aortic valve replacement, but this approach may be an attractive therapeutic option in the future. Currently, the role of surgical therapy in comparison to transcatheter techniques in secondary MR is not well defined.

Chordal cutting in ischemic mitral regurgitation: a propensity-matched study

OBJECTIVE

The optimal surgical treatment of ischemic mitral regurgitation (MR) has not been well defined. Second-order chordal cutting (CC), in selected patients, can improve surgical outcomes.

METHODS

From 2007 to 2011, 31 patients underwent CC for ischemic MR. The indication was the presence of increased tethering of the anterior leaflet, with a bending angle (BA) <145°. Patients with same echocardiographic characteristics were identified and propensity matched for age, ejection fraction (EF), MR grade, diameters, and BA. Only patients with preoperative and follow-up echocardiograms were included and divided into 2 groups of 26 patients each, CC and no-CC.

RESULTS

Preoperatively, in the CC and no-CC groups, the age was 61 ± 9 and 62 ± 10 years, EF was 31% ± 5% and 29% ± 8%, MR grade (0-4) was 3.6 ± 0.6 and 3.3 ± 0.8, and diastolic and systolic dimension was 56 ± 7 and 43 ± 8 mm and 57 ± 11 and 44 ± 11 mm, respectively. The New York Heart Association class and BA was 2.7 ± 0.6 and 2.6 ± 0.7 and 137° ± 4° and 137° ± 6°, respectively. All patients underwent overreductive annuloplasty. In the CC group, second-order chords were cut using aortotomy. After a mean of 33 ± 15 months, the MR grade was 0.6 ± 0.6 and 1.1 ± 0.8 (P = .014) and the EF was 40% ± 5% and 35% ± 7% (P = .005) in the CC and no-CC groups, respectively. The corresponding diastolic and systolic diameters were 52 ± 5 and 38 ± 8 mm and 53 ± 11 and 41 ± 12 mm (P = NS). The modifications were significant only in the CC group (P = .022 and P = .029 for the diastolic and systolic dimensions, respectively). The corresponding New York Heart Association class decreased to 1.1 ± 0.3 and 1.5 ± 0.6 (P = .004). The BA increased to 182° ± 4° in the CC (P < .001) and remained unchanged (137° ± 6°) in the no-CC group.

CONCLUSIONS

In selected patients with a BA <145° and coaptation depth ≤10 mm, CC is related to less MR return or persistence, improved EF, and lower New York Heart Association class.