Comparison of mitral competence after mitral repair with papillary muscle approximation versus papillary muscle relocation for functional mitral regurgitation

Mid-term outcomes of surgical aortic valve replacement using a mosaic porcine bioprosthesis with concomitant mitral valve repair

This study retrospectively evaluated the mid-term outcomes of surgical aortic valve replacement (SAVR) using a stented porcine aortic valve bioprosthesis (Mosaic; Medtronic Inc., Minneapolis, MN, USA) with concomitant mitral valve (MV) repair. From 1999 to 2014, 157 patients (median [interquartile range] age, 75 [70-79] years; 47% women) underwent SAVR with concomitant MV repair (SAVR + MV repair), and 1045 patients (median [interquartile range] age, 76 [70-80] years; 54% women) underwent SAVR only at 10 centers in Japan as part of the long-term multicenter Japan Mosaic valve (J-MOVE) study. The 5-year overall survival rate was 81.5% ± 4.1% in the SAVR + MV repair group and 85.1% ± 1.4% in the SAVR only group, and the 8-year overall survival rates were 75.2% ± 5.7% and 78.1% ± 2.1%, respectively. Cox proportional hazards analysis showed no significant difference in the survival rates between the two groups (hazard ratio, 0.87; 95% confidence interval, 0.54-1.40; P = 0.576). Among women with mild or moderate mitral regurgitation who were not receiving dialysis, those who underwent SAVR + MV repair, were aged > 75 years, and had a preoperative left ventricular ejection fraction of 30-75% tended to have a lower mortality risk. In conclusion, this subgroup analysis of the J-MOVE cohort showed relevant mid-term outcomes after SAVR + MV repair.

Surgical repair of ischemic mitral regurgitation: one ring does not fit all

PURPOSE OF REVIEW

The review summarizes the key parameters that can aid in determining the optimal treatment of ischemic mitral regurgitation (IMR).

RECENT FINDINGS

Left ventricular (LV) and mitral valve (MV) parameters are important for surgical planning and risk stratification in IMR. Although LV dimensions is one of the main parameters used in the guidelines, volumes more accurately depict LV remodelling. Furthermore, wall motion abnormalities and wall motion score index can also be useful for surgical planning in treatment of IMR. Viability is best measured with cardiac magnetic resonance, but it is not feasible in certain centres. In contrast, measurement of strain with echocardiography is an emerging and feasible tool for estimating viability. MV leaflet tethering and pattern measured with echocardiography are also useful for MV surgery. Anterior leaflet excursion angle can identify patients in whom undersized ring annuloplasty is potentially unsuitable.

SUMMARY

Treatment of IMR relies on accurate parameters that can determine the optimal surgical approach. In some patients, lack of viable myocardium suggests inadequacy of revascularization and thus, an adjunctive left ventricular reconstruction may be necessary. Degree and pattern of MV leaflet tethering can indicate whether ring annuloplasty, which is the most common repair technique, is sufficient or an adjunctive sub-valvular intervention is beneficial.

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.

Left Ventricular Thinning and Distension in Pig Hearts as a Reproducible Ex Vivo Model of Functional Mitral Regurgitation

Functional mitral regurgitation in the setting of an enlarged heart is challenging to repair surgically with an annular approach, and the need to develop subannular and ventricular approaches is recognized yet unrealized because of the lack of models for investigations. In this study, we report a novel model of functional mitral regurgitation induced by left ventricular thinning and distension in pig hearts. Seven pig hearts were explanted at a local slaughterhouse, and left ventricular distension induced by thinning the ventricular myocardium by 60-65% of its original thickness. Distension of the thinned hearts with a 120 mmHg column confirmed significant left ventricular dilatation and mitral valve tethering. These hearts were then mounted into a pulsatile flow model and animated at 120 mmHg left ventricular pressure, 5 L/min cardiac output at 70 beats/min. Echocardiography was used to assess valvular kinematics and hemodynamics. Left ventricular wall thickness reduced by 60.5% ± 10.1% at the basal plane, 64.8% ± 11.3% at the equatorial plane, and 64.0% ± 11.4% at the apical plane after thinning. Upon distension, ventricular volumes increased by 852.4% ± 639.8% after left ventricular thinning, with an 89.5% ± 33.9% increase in sphericity index. Mitral valve systolic tenting height increased from 7.92 ± 2.06 to 15.02 ± 3.89 mm, systolic tethering area increased from 130.7 ± 38.2 to 409.9 ± 124.6 mm and an average mitral regurgitation fraction of 24.4% ± 16.6% was measured. In a case study, use of multimodality imaging to test the efficacy of transcatheter mitral devices was confirmed. Ventricular wall thinning leading to passive left ventricular distension and dilatation is a reproducible ex vivo model of mitral valve tethering and functional mitral regurgitation, which in combination with multimodality imaging provides a good simulation model.

Influence of preoperative right ventricular function on left ventricular remodeling and survival after subvalvular repair for functional mitral regurgitation

OBJECTIVES

The objective of this study was to analyze our surgical experiences with mitral valve plasty (MVP) combined with subvalvular procedures (SVPs) for functional mitral regurgitation (FMR) and to determine which preoperative factors affected clinical outcomes.

METHODS

This study retrospectively analyzed 33 patients who underwent MVP combined with SVPs for FMR with a left ventricular ejection fraction lower than 40% and advanced remodeled left ventricles. The mean follow-up period was 49 ± 33 months.

RESULTS

The preoperative mean right ventricular fractional area change (RVFAC) used to quantify right ventricular (RV) systolic function was 26 ± 11%. Sixteen patients (48%) had an RVFAC < 26%. One patient died during hospital stay, and nine more patients died of cardiac causes during follow-up. The 3- and 5-year rates of freedom from cardiac-related mortality were 78% and 68%, respectively. RVFAC was the significant predictor of cardiac-related mortality in a univariate analysis (risk ratio [RR] = 0.92, 95% confidence interval [CI] 0.85-0.99, p = 0.03) and demonstrated a non-significant tendency to predict cardiac-related mortality in the Cox multivariate analysis (RR = 0.94, 95% CI 0.86-1.003, p = 0.08). Continued reverse left ventricular remodeling was associated with an RVFAC ≥ 26%. At 3 years, there was also a significant difference in survival rates of cardiac-related mortality between patients with an RVFAC ≥ 26% and < 26% (94% vs. 61%; p = 0.03).

CONCLUSIONS

Preoperative RV function affected left ventricular remodeling and cardiac-related mortality after MV surgery. MVP combined with SVPs for FMR provided promising results for patients without severe RV dysfunction.

Clinical Outcomes of a Customized Mitral Valve Plasty for Functional Mitral Regurgitation with a Low Ejection Fraction and Implications for Preoperative Right Ventricular Function

Purpose: To evaluate clinical outcomes of customized mitral valve plasty (MVP) for the treatment of functional mitral regurgitation (FMR) with a low ejection fraction (EF) and to determine which preoperative factors affected the clinical outcome.

Methods and Results: MVP was adjusted according to the degree of left ventricle (LV) remodeling. We performed mitral annuloplasty (MAP) alone in 14 patients and added subvalvular procedures (SVPs) in 22 patients at a high risk of recurrent MR. During follow-up, reverse LV remodeling was obtained and the 3-year and 5-year non-recurrence rates of MR grade ≥2 were 94% and 89%, respectively. Two patients died during their hospital stay, and four more patients died of cardiac causes during follow-up. The 3-year and 5-year rates of freedom from cardiac-related mortality were 86% and 81%, respectively; no significant difference was observed between the two treatment groups. Right ventricular fractional area change (RVFAC) was a significant predictor of cardiac mortality. Patients with an RVFAC of <26% had significantly poorer cardiac-related mortality (71% at 3 years) than those with an RVFAC of ≥26% (95% at 3 years).

Conclusion: Customized MVP provided durable mitral competence and reverse LV remodeling. Preoperative RV function was associated with cardiac-related mortality.

Papillary muscle intervention vs mitral ring annuloplasty in ischemic mitral regurgitation

Background and Aims

The main pathophysiological factor of chronic ischemic mitral regurgitation (MR) is the outward displacement of the papillary muscles (PMs) leading to leaflet tethering. For this reason, papillary muscle intervention (PMI) in combination with mitral ring annuloplasty (MRA) has recently been introduced into clinical practice to correct this displacement, and to reduce the recurrence of regurgitation.

Methods

A meta‐analysis was conducted comparing the outcomes of PMI and MRA performed in combination vs MRA performed alone, in terms of MR recurrence and left ventricular reverse remodeling (LVRR). A meta‐regression was carried out to investigate the impact of the type of PMI procedure on the outcomes.

Results

MR recurrence in patients undergoing both PMI and MRA was lower than in those who only had MRA (log incidence rate ratio, −0.66; lower‐upper limits, −1.13 to 0.20; I² = 0.0%; p = .44; Egger's test: intercept 0.35 [−0.78 to 1.51]; p = .42).

The group with both PMI and MRA and that with only MRA showed a slightly higher reduction in left ventricular diameters (−5.94%; −8.75% to 3.13%,). However, in both groups, LVRR was <10%. No difference was detected between PM relocation/repositioning and papillary muscle approximation in terms of LVRR (p = .33).

Conclusions

Using PMI and MRA together has a lower MR recurrence than using MRA alone. No significant LVRR was observed between the two groups nor between the PMI techniques employed.

Clinical manifestations, diagnosis, and treatment of ischemic mitral regurgitation: a review

Ischemic mitral regurgitation (IMR) is a frequent complication after acute myocardial infarction (AMI) associated with a worse prognosis. The pathophysiological mechanisms of IMR are not fully understood, but it is known to be a complex process in which ventricular remodelling is the main causal factor. The various imaging techniques in cardiology and echocardiography fundamentally have contributed significantly to clarify the mechanisms that cause and progressively aggravate IMR. At present, different therapeutic options, the most important of which are cardio-surgical, address this problem. Nowadays the improvement in cardiac surgery and transcatheter therapies, have shown a therapeutic advance in IMR management. IMR is a predictor of poor prognosis in patients with heart failure and depressed left ventricular (LV) systolic function. However, it remains controversial whether mitral regurgitation (MR) in these patients is a consequence of dilation and dysfunction of the LV, or whether it contributes to worsening the prognosis of the ventricular dysfunction. Given that echocardiography has a fundamental reference role in the identification, graduation of severity and evaluation of the therapeutics used in the treatment of MR, we are going to focus on it over the rest of the imaging techniques. In contrast to primary MR the benefits of mitral surgery in patients with secondary MR are uncertain. Therefore, we will comment fundamentally on the role of mitral surgery in patients with IMR, with an update of the different surgical interventions available, without forgetting to mention the other therapeutic options currently available.