Restrictive mitral valve annuloplasty for chronic ischaemic mitral regurgitation: outcomes of flexible versus semi-rigid rings

Secondary mitral regurgitation surgical management: a narrative review

Background and Objective

The most common valvular heart disease in the US is moderate to severe mitral regurgitation (MR). Function MR or secondary MR comprises many of these cases. Moderate and severe secondary MR are independently associated with increased all-cause mortality and rehospitalization for heart failure. Both ischemic and nonischemic cardiomyopathy can cause secondary MR via similar pathophysiology that leads to inadequate valve leaflets coaptation. The management of secondary MR is complex. The optimal treatment strategy for secondary MR remains controversial, reflected in the vast array of treatment options and the complexity of therapeutic decision-making. Several surgical mitral valve repair techniques have been described in the literature. Many of these aims to facilitate adequate valve leaflet coaptation. In this review, the pathophysiology of MR is described with a focus on evaluating and managing secondary MR.

Methods

A literature review was performed using PubMed and Google Scholar. Clinical trials, meta-analyses, randomized controlled trials, reviews, and systematic reviews were considered from January 1, 1995 through December 31, 2022. Articles published in languages other than English with limited text availability were excluded.

Key Content and Findings

Optimal therapeutic approach in severe secondary MR is complex and several patient factor should be considered. We provide a framework for the surgical management of secondary MR based on echocardiographic parameters, the presence of ischemia, and myocardial viability.

Conclusions

Further study is needed to guide the selection of patients most likely to benefit from mitral valve repair or replacement in the setting of secondary MR.

Long-term follow-up of posterior mitral leaflet extension for Type IIIb ischemic mitral regurgitation

Objective

Ischemic mitral regurgitation (MR) is generally associated with very poor outcomes and disappointing results, despite a seemingly perfect initial repair and optimal revascularization. We previously published our intermediate-term results of posterior leaflet augmentation without follow-up extending beyond 4 years. Our objective is to assess long-term durability of the repair, survival, and the causes of late mortality.

Methods

Ninety-one patients with severe (4+) Carpentier Type IIIb ischemic MR underwent repair in a single center between 2003 and 2022 by method of posterior leaflet extension using a patch of bovine pericardium and a true-sized remodeling annuloplasty ring, with or without surgical revascularization. Serial echocardiography was performed over the years to ascertain valve competence and degree of ventricular remodeling, in addition to telephone follow-up and chart reviews.

Results

The average age of patients was 67 ± 9.6 years. Mean follow-up was 8 ± 5 years with some extending to almost 20 years. One-, 5-, and 10-year freedom from recurrent significant MR, characterized as moderate or severe MR, was 98.6%, 85.5%, and 71.3%, respectively. Thirty-day mortality was 6.5%. One-, 5-, and 10-year survival was 85.5%, 64.4%, and 43.3%, respectively. Of all the mortalities, only 17.5% were proven to be directly cardiac related.

Conclusions

The suggested repair technique offers satisfactory long-term outcomes with minimal residual regurgitation in surviving patients when used in context of ischemic MR. Despite durable repair, we have discovered that poor long-term survival is not directly related to cardiovascular causes.

Computational Modeling of the Subject-Specific Effects of Annuloplasty Ring Sizing on the Mitral Valve to Repair Functional Mitral Regurgitation

Surgical repair of functional mitral regurgitation (FMR) that occurs in nearly 60% of heart failure (HF) patients is currently performed with undersizing mitral annuloplasty (UMA), which lacks short- and long-term durability. Heterogeneity in valve geometry makes tailoring this repair to each patient challenging, and predictive models that can help with planning this surgery are lacking. In this study, we present a 3D echo-derived computational model, to enable subject-specific, pre-surgical planning of the repair. Three computational models of the mitral valve were created from 3D echo data obtained in three pigs with HF and FMR. An annuloplasty ring model in seven sizes was created, each ring was deployed, and post-repair valve closure was simulated. The results indicate that large annuloplasty rings (> 32 mm) were not effective in eliminating regurgitant gaps nor in restoring leaflet coaptation or reducing leaflet stresses and chordal tension. Smaller rings (≤ 32 mm) restored better systolic valve closure in all investigated cases,but excessive valve tethering and restricted motion of the leaflets were still present. This computational study demonstrates that for effective correction of FMR, the extent of annular reduction differs between subjects, and overly reducing the annulus has deleterious effects on the valve.

Prognosis for Mitral Valve Repair Surgery in Functional Mitral Regurgitation

Purpose: Our aim was to evaluate the development of new significant mitral regurgitation and long-term survival after mitral repair surgery in functional mitral regurgitation.

Methods: A retrospective observational analysis of the recurrence of functional mitral regurgitation (ischemic and nonischemic) and global mortality during follow-up of 176 patients who underwent mitral repair surgery between 1999 and 2018 in our center was conducted.

Results: The etiology of functional mitral regurgitation was ischemic in 55.7% of cases. After surgery, mitral regurgitation was 0-I in 92.3% of cases. We conducted a long-term clinical follow-up of a mean 42.2 months and an echocardiographic follow-up of a mean 41.8 months. We observed mitral regurgitation of at least grade II in 52 patients (36.9%). Survival at 1, 3, and 5 years was 78.8%, 66.7%, and 52.3%, respectively. Predictive factors for global mortality were age (hazard ratio = 1.038, p = 0.01) and a depressed preoperative ejection fraction. After a competing risk analysis, we found the only predictive factor for the recurrence of mitral regurgitation in our series to be age (sub-hazard ratio = 1.03, 95% confidence interval = 1.01–1.06, p = 0.016).

Conclusion: Repair surgery for functional mitral regurgitation shows age as the only independent predictor of recurrence. Age and depressed ejection fraction were predictors of mortality.