Surgical options of ischemic mitral regurgitation

Surgical Treatment of Ischemic Mitral Regurgitation: Valve Repair Versus Replacement

PURPOSE OF REVIEW

Ischemic mitral regurgitation (MR), which occurs in about 20-30% patients with a prior myocardial infarction, is associated with worsening heart failure and an increase in cardiovascular mortality. It should be treated surgically if certain hemodynamic severity criteria are met and in patients who continue to experience symptoms of heart failure despite optimal medical therapy. However, current guidelines do not suggest which of the available approaches to mitral valve surgery-mitral valve (MV) repair or replacement (MVR) is superior for this indication. While MV repair is reported to confer improved survival, MVR may provide higher rates of freedom from recurrent MR. This article attempts to provide the reader with a comprehensive review and comparison of current techniques of mitral valve surgery in patients with severe ischemic MR.

RECENT FINDINGS

The first randomized trial to compare MV repair versus MVR in patients with severe ischemic MR, the Cardiothoracic Surgical Trials Network (CTSN) trial, was recently concluded and reported no significant difference in the primary outcome of left ventricular end systolic volume index between the two approaches at either 1- or 2-year follow-ups. Data comparing approaches of MV repair and MVR for ischemic MR is largely limited to small, non-randomized retrospective trials. The only randomized trial data to examine this issue suggested no difference in mortality with either MVR or MV repair; however, MVR was shown to be consistently associated with higher rates of MR recurrence. Certain echocardiographic features have been reported to predict poor outcomes with MVR and may help refine the selection of the surgical approach in the individual patient.

Mitral valve repair and subvalvular intervention for secondary mitral regurgitation: a systematic review and meta-analysis of randomized controlled and propensity matched studies

BACKGROUND

Combining a ring annuloplasty (Ring) with a mitral subvalvular intervention (Ring + subvalvular) in patients with secondary mitral regurgitation (MR) may improve mitral valve (MV) repair durability. However, the outcomes of this strategy compared with a Ring only, have not been clearly defined.

METHODS

A systematic review and meta-analysis was performed utilizing randomized controlled and propensity matched studies which compared a Ring + subvalvular versus Ring MV repair for the treatment of secondary MR. Risk ratio (RR), weighted mean difference (MD), and the 95% confidence interval (CI) were calculated by the Mantel-Haenszel and inverse-variance methods, for clinical outcomes and echocardiographic measures of follow-up MR, left ventricular (LV) reverse remodeling, and MV apparatus geometry.

RESULTS

Five studies were identified, with a total of 397 patients. Baseline characteristics were similar between groups, and all patients had moderate to severe secondary MR, with the vast majority in the setting of ischemic cardiomyopathy. A Ring + subvalvular repair consisted of papillary muscle approximation (n=2), papillary muscle relocation (n=2), or secondary chordal cutting (n=1). Follow-up ranged from 10.1 (mean range =0.25-42) to 69 [interquartile range (IQR) =23-82] months. When compared with Ring only at last follow-up, a Ring + subvalvular MV repair was associated with: (I) a smaller MR grade (MD =-0.44, 95% CI -0.69 to -0.19; P=0.0005); (II) a reduced risk of moderate or greater recurrent MR (RR =0.43, 95% CI, 0.27-0.66; P=0.0002); (III) a smaller mean LV end-diastolic diameter (MD =-3.56 mm, 95% CI -5.40 to -1.73; P=0.0001) and a greater ejection fraction (MD =2.64%, 95% CI, 0.13-5.15; P=0.04); and, (IV) an improved MV apparatus geometry. There were no differences in operative mortality, post-operative morbidity, or follow-up survival between surgical approaches.

CONCLUSIONS

When compared with Ring only, a Ring + subvalvular MV repair is associated with greater LV reverse remodeling and systolic function, less recurrence of moderate or greater MR, and an improved geometry of the MV apparatus at short and mid-term follow-up.

Anterior Mitral Leaflet Augmentation for Ischemic Mitral Regurgitation Performed Via a Right Thoracotomy Approach

Ischemic mitral regurgitation (MR) after myocardial infarction is associated with poor long-term survival, and the optimal treatment strategy remains debated. The most common repair technique used is a restrictive annuloplasty. However, up to 15% to 30% of patients experience recurrent MR owing to progressive left ventricular remodeling and geometric distortion of the mitral valve apparatus. Anterior mitral leaflet augmentation using a pericardial patch, in combination with a true-sized mitral annuloplasty, has been proposed as an adjunctive technique to increase the durability of valve repair for ischemic MR. Herein, we describe 2 cases of anterior mitral leaflet augmentation with annuloplasty repair for severe ischemic MR via a minimally invasive right thoracotomy, and review the literature regarding patient selection and clinical outcomes of this technique.

Mitral valve repair for ischemic mitral regurgitation: lessons from the Cardiothoracic Surgical Trials Network randomized study

Approximately 30% to 50% of patients will develop ischemic mitral regurgitation (MR) after a myocardial infarction, which is a result of progressive left ventricular remodeling and dysfunction of the subvalvular apparatus, and portends a poor long-term prognosis. Surgical treatment is centered on mitral valve repair utilizing a restrictive annuloplasty, or valve replacement with preservation of the subvalvular apparatus. In the recent Cardiothoracic Surgical Trials Network (CSTN) study, patients with severe ischemic MR were randomized to mitral valve repair with a restrictive annuloplasty versus chordal-sparing valve replacement, and concomitant coronary artery bypass grafting, if indicated. At 2-year follow-up, mitral valve repair was associated with a significantly higher incidence of moderate or greater recurrent MR and heart failure, with no difference in the indices of left ventricular reverse remodeling, as compared with valve replacement. The current appraisal aims to provide insight into the CSTN trial results, and discusses the evidence supporting a pathophysiologic-guided repair strategy incorporating combined annuloplasty and subvalvular repair techniques to optimize the outcomes of mitral valve repair in ischemic MR.

A Meta-Analysis of Ring Annuloplasty Versus Combined Ring Annuloplasty and Subvalvular Repair for Moderate-to-Severe Functional Mitral Regurgitation

BACKGROUND

A ring annuloplasty (Ring) for moderate-to-severe functional mitral regurgitation (MR) is associated with suboptimal outcomes, and adjunctive subvalvular repair techniques (Ring + Subvalvular) have been advocated to improve repair durability. However, the outcomes of this strategy are not clearly defined.

METHODS

A systematic review was performed to identify studies that compared a Ring versus Ring + Subvalvular repair for the treatment of moderate-to-severe functional MR. A meta-analysis was conducted on clinical outcomes and echocardiographic measures of follow-up MR and left ventricular reverse remodeling. Risk ratio (RR) and mean difference (MD) were calculated by the Mantel-Haenszel and Inverse Variance methods under a fixed or random effects model, as appropriate.

RESULTS

Seven non-randomized studies were identified, with a total of 531 patients (Ring = 301, Ring + Subvalvular = 230). At follow-up (range 30-47 months), a Ring + Subvalvular repair was associated with a lower mortality (RR = 0.59, 95%confidence interval [CI] 0.37-0.94, p = 0.03), greater freedom from moderate or greater MR (RR = 0.44, 95%CI 0.27-0.72, p = 0.001), and improved left ventricular end-diastolic diameter (MD = -3.49 mm, 95%CI -5.45 to -1.53, p = 0.0005) and New York Heart Association functional class (MD = -0.25, 95%CI -0.42 to -0.08, p = 0.004). A trend toward a reduced risk of reoperation for recurrent MR was noted with a combined Ring + Subvalvular repair (RR = 0.28, 95%CI 0.06-1.22, p = 0.09). Finally, a Ring + Subvalvular repair did not impact operative mortality or follow-up left ventricular ejection fraction.

CONCLUSION

A combined Ring + Subvalvular repair for moderate-to-severe functional MR can be safely performed, and may improve mid-term outcomes, as compared with Ring alone.

Echocardiographic assessment of mitral valve regurgitation, pattern and prevalence, expanding clinical awareness through an institutional survey with the perspective of a quality improvement project

BACKGROUND

Mitral regurgitation (MR) is frequently reported in everyday echocardiograms; accurate assessment is essential for appropriate management and decision making.

OBJECTIVE

We performed a self-audit in order to define the prevalence and pattern of MR and to evaluate methods of assessment with the perspective of developing a quality improvement project.

METHODS AND SETTING

This retrospective analytical study was conducted in a university hospital.

INCLUSION CRITERIA

age more than 18 years and medical records available within the facility, including a "complete" medical history. Using the picture archiving and communication system, we reviewed 961 echocardiograms performed over a 6-month period. The methods of assessment of native mitral valve regurgitation were reported, and also relevant medical data were collected using an electronic archiving system.

RESULTS AND DISCUSSION

Among the 961 patients reviewed, 322 (33.50%) had MR, with variable grades. MR pattern (organic versus functional) was not specified in 49.68% of cases. "Eyeball" assessment and "color jet area" were the most frequently used methods for MR assessment (90.06% and 27.95%, respectively), while "vena contracta" and "flow convergence" methods were rarely implemented (1.55% and 2.17%, respectively). Discussion is made according to current guidelines, while showing the strengths and weaknesses of each method.

CONCLUSION

The prevalence of MR was 33.50%, and in nearly half of cases, the MR pattern was not specified. Qualitative and semi-quantitative methods of assessment were mostly used; quantitative assessment should be implemented more frequently, in accordance with current guidelines. Increasing clinical awareness by creating and implementing a quality improvement project is essential in this context.