Early and Late Results of Restrictive Mitral Valve Annuloplasty in 121 Patients with Cardiomyopathy and Chronic Mitral Regurgitation

Does Sustained Reduction of Functional Mitral Regurgitation Impact Survival?

Functional mitral regurgitation (FMR) is associated with increased mortality and has been considered a marker for advanced heart disease, yet the value of mitral valve repair (MVr) in this population remains unclear. This study aims to evaluate the impact of reducing FMR burden through surgical MVr on survival. Patients with severe FMR who underwent MVr with an undersized, complete, rigid, annuloplasty between 2004 and 2017 were assessed (n = 201). Patients were categorized based on grade of recurrent FMR (0-4). Time-to-event Kaplan-Meier estimations of freedom from death or reoperation were performed using the log-rank test. Cox proportional hazards models evaluated all-cause mortality and reported in hazards ratios (HR) and 95% confidence intervals (CI). Patients were categorized by postoperative recurrent FMR: 45% (91/201) of patients had grade 0, 29% (58/201) grade 1, 20% (40/201) grade 2, 2% (4/201) grade 3%, and 4% (8/201) grade 4. The cumulative incidence of reoperation with death as a competing risk was higher in patients with grades ≥3 recurrent FMR compared to grades ≤2 (44.6% vs 14.6%, subhazard ratio 3.69 [95% CI, 1.17-11.6]; P = 0.026). Overall freedom from death or reoperation was superior for recurrent FMR grades ≤2 compared to grades ≥3 (log-rank P < 0.001). Increasing recurrent FMR grade was independently associated with mortality (HR 1.30 [95% CI, 1.07-1.59] P = 0.009). Reduced postoperative FMR grade resulted in an incrementally lower risk of death or reoperation after MVr. These results suggest that achieving a durable reduction in FMR burden improves long-term survival.

Ischemic Mitral Regurgitation: Current Understanding and Surgical Options

Secondary, or functional, mitral regurgitation (MR) occurs with impaired coaptation of structurally normal valve leaflets due to abnormal structure and/or function of the left ventricle (LV). A leading cause of functional mitral regurgitation is ischemic cardiomyopathy, resulting in left ventricular dysfunction and subsequent congestive heart failure (CHF) and ischemic mitral regurgitation (IMR). The value of surgical or transcatheter correction of IMR remains controversial, since the underlying pathology of IMR is attributed to a dysfunctional left ventricle. However, even mild IMR has been shown to be harmful to CHF patients, as IMR is both a surrogate of advanced CHF and an independent contributor to CHF morbidity and mortality. While observational and randomized studies have examined surgical treatment of IMR with conflicting outcomes, additional well-designed randomized controlled trials should be performed to further clarify the optimal treatment for IMR. Additionally, close attention should be paid to the quality of interventions performed, as durable reduction in IMR provides the best hope of a positive clinical outcome. This review focuses on the pathophysiology of IMR, current evidence regarding surgical and transcatheter interventions, and future directions in management of IMR.

Restrictive Mitral Valve Annuloplasty: Prognostic Implications of Left Ventricular Forward Flow

BACKGROUND

Surgical mitral valve repair for severe secondary mitral regurgitation (MR) remains controversial. The association of MR reduction and changes in left ventricular (LV) hemodynamics with survival has not been investigated. We investigated the independent associates of outcomes in heart failure patients with severe secondary MR who underwent surgical mitral valve repair.

METHODS

Patients (n = 130, 62 ± 12 years old, 55% men) with chronic severe secondary MR and impaired LV ejection fraction (<0.50, mean 0.31 ± 0.10) treated with surgical mitral valve repair were included. Echocardiographic LV forward stroke volume and LV forward ejection fraction were measured at baseline and at discharge. All-cause mortality was the primary endpoint, and the combination of major adverse cardiac-related events and all-cause mortality was the secondary endpoint.

RESULTS

At hospital discharge, 77% of patients showed no residual MR and 23% showed mild MR. LV volumes reduced significantly, whereas LV ejection fraction remained unchanged. In contrast, LV forward stoke volume (53 ± 24 mL versus 64 ± 22 mL, p < 0.001) and LV forward ejection fraction (0.32 ± 0.16 versus 0.48 ± 0.24, p < 0.001) significantly increased at discharge. During a median follow-up of 3.44 years, 33 patients (29%) died and 40 had major adverse cardiac-related events. On multivariable analysis, LV forward stroke volume after repair was independently associated with all-cause mortality (hazard ratio 0.98, p = 0.047) and with the combined endpoint (hazard ratio 0.98, p = 0.045) after correcting for other baseline, procedural, and postrepair characteristics.

CONCLUSIONS

In patients with severe secondary MR treated with surgical repair, LV forward flow was independently associated with better survival and lower risk of the combined endpoint.

Computer-based comparison of different methods for selecting mitral annuloplasty ring size

Background

Ring sizing for mitral valve annuloplasty is conventionally done intraoperatively using specific ‘sizer’ instruments, which are placed onto the valve tissue. This approach is barely reproducible since different sizing strategies have been established among surgeons. The goal of this study is to virtually apply different sizing methods on the basis of pre-repair echocardiography to find out basic differences between sizing strategies.

Methods

In three-dimensional echocardiographs of 43 patients, the mitral annulus and the contour of the anterior mitral leaflet were segmented using MITK Mitralyzer software. Similarly, three-dimensional virtual models of Carpentier-Edwards Physio II annuloplasty rings and their corresponding sizers were interactively generated from computer tomography images. For each patient, the matching annuloplasty ring was selected repeatedly according to popular sizing strategies, such as the height of anterior mitral leaflet, the intercommissural distance and the surface area of anterior mitral leaflet. The areas of the selected rings were considered as the neo-surface area of the mitral annulus after implantation.

Results

The sizing of the mitral valve according to the height of anterior mitral leaflet (mean ring size = 29.9 ± 3.90), intercommissural distance (mean ring size = 37.5 ± 1.92) or surface area of anterior mitral leaflet (mean ring size = 32.7 ± 3.3) led to significantly different measurements (p ≤ 0.01). In contrary to intercommissural distance, height and surface area of the anterior mitral leaflet exhibited significant variations between the patients (p ≤ 0.01). The sizing according to the height of anterior mitral leaflet led to the maximal reduction of the mitral annulus surface area followed by the sizing according to the surface area of anterior mitral leaflet and finally by the intercommissural distance.

Conclusions

This novel comprehensive computer-based analysis reveals that the surveyed sizing methods led to the selection of significantly different annuloplasty rings and therefore underscore the ambiguity of routinely applied annuloplasty sizing strategies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13019-017-0571-y) contains supplementary material, which is available to authorized users.

Pre-Operative Left Ventricular Torsion, QRS Width/CRT, and Post-Mitral Surgery Outcomes in Patients With Nonischemic, Chronic, Severe Secondary Mitral Regurgitation

The selection of appropriate candidates for mitral surgery among symptomatic patients with nonischemic, chronic, secondary severe mitral regurgitation (NICSMR) remains a clinical challenge. We studied 50 consecutive symptomatic NICSMR patients for a median follow-up of 2.5 years after mitral surgery and concluded that the pre-operative 2-dimensional speckle tracking echocardiography-derived left ventricular torsional profile and QRS width/cardiac resynchronization therapy are potentially important prognostic indicators for post-surgery survival and reverse remodeling.

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Determining which patients with NICSMR will benefit from MS is a clinical dilemma.

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LV torsion (which is a shear strain, not volume strain such as ejection fraction and originates in LV myocardial architectures) may reveal the myopathic conditions and reflect intra-LV electrical conduction.

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The LV torsional profile predicted post-MS outcomes in NICSMR patients with a narrow QRS but not in those with a wide QRS.

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The findings may help to resolve the clinical dilemma and identify appropriate candidates for mitral surgery (and other resources) in patients with NICSMR.

Economic burden of functional and organic mitral valve regurgitation

BACKGROUND

Very little is known about the costs of mitral regurgitation (MR) in Europe.

AIM

To evaluate the cost of MR from a French National Payer perspective, based on annual costs of surgical and non-surgical patients.

METHODS

A 12-month retrospective population-based analysis of patient demographics, outcomes and acute hospital and post-discharge resource utilizations, extracted from the 2009 French Medical Information System.

RESULTS

A total of 19,868 patients with MR were identified. Surgical group (n=4099): index hospitalization length of stay (LOS), 17±14.7 days; patients discharged to rehabilitation, 72% (LOS 23±16 days); 12-month rehospitalization rate, 25%; total cost per surgical patient, €24,871±13,940 (ranging from €21,970±11,787 for mitral valve repair [n=2567, 62.6%] to €29,732±15,796 for mitral valve replacement). Non-surgical group (n=15,769): number of hospitalizations over 12 months, 3.1±1.5 (LOS 23.5±20.4 days); admitted to rehabilitation, 24% (LOS 38.8±37.6 days); total cost per patient, €12,177±10,913 (varying between €9957±9080 and €13,538±11,692 for those without and with heart failure [HF], respectively). The total observed cost for 19,868 MR patients over 12 months was €292.8 million: surgical group, €100.8 million; medical group €192.0 million. Patients with MR and HF who were managed medically consumed 45% (€132.3 million) of the overall annual cost of MR.

CONCLUSION

The costs of care associated with MR are highly heterogeneous. There are significant differences in costs and resources used between the surgical and medical MR subgroups, with further differences depending on type of surgery and presence of HF.

[Mitral regurgitation in heart failure. Surgical therapy]

The optimal treatment of mitral regurgitation concomitant to heart failure remains controversial. A lack of consensus between cardiologists and cardiac surgeons, because of limited studies and heterogeneous data, has led to vaguely defined guidelines and different handling in the clinical routine in the past. However, progress in the operative management with excellent results of individual experienced centers suggests that a variety of patients might benefit from surgical therapy. Each patient should be evaluated individually regarding the benefits of surgical therapy which requires an interdisciplinary approach ("heart team") due to the complex pathophysiology and demanding diagnostics.

Long-term echocardiographic changes in left ventricular size and function following surgery for severe mitral regurgitation

Background

Chronic mitral regurgitation (MR) results in a state of chronic left ventricular (LV) volume overload, resulting in compensatory dilatation. Mitral valve (MV) surgery for regurgitation reduces LV preload but increases LV afterload. Few data are available documenting subsequent changes in LV size and function over time following MV surgery for severe regurgitation in unselected populations.

Material/Methods

Pre- and postoperative echocardiograms (n=454) acquired from 108 consecutive patients with chronic MR who underwent MV surgery were analyzed.

Results

LV diastolic diameter was 4 mm smaller on postoperative compared to preoperative exams, whereas LV fractional shortening (FS) was unchanged. Linear regression analysis showed no change in LV diastolic diameter over time postoperatively, whereas LV FS increased over time following surgery. Improvement in LV FS occurred at an average rate of 1.6% per year (95% CI, 0.2–2.9). Subgroups were small, but the same secular trends were generally noted in groups with or without coronary artery bypass graft surgery (CABGS) and in those with or without mitral leaflet disease.

Conclusions

Following MV surgery for MR, LV diastolic diameter reduces by 2 mm at the time of surgery, but then remains stable over time. Improvement in LV function over time postoperatively was only seen in those without concomitant CABGS, possibly related to less baseline myocardial scarring in this group.

Surgical treatment of functional mitral regurgitation in dilated cardiomyopathy

Functional mitral regurgitation is a significant complication of end-stage cardiomyopathy. Dysfunction of one or more components of the mitral valve apparatus occurs in 39-74% and affects almost all heart failure patients. Survival is decreased in subjects with more than mild mitral regurgitation irrespective of the aetiology of heart failure. The goal of treating functional mitral regurgitation is to slow or reverse ventricular remodelling, improve symptoms and functional class, decrease the frequency of hospitalization for congestive heart failure, slow progression to advanced heart failure (time to transplant) and improve survival. This article reviews the role of mitral valve surgery in patients with heart failure and dilated cardiomyopathy.

Restrictive mitral annuloplasty for functional mitral regurgitation: acute hemodynamics and serial echocardiography

BACKGROUND

Long-term effects of restrictive mitral annuloplasty (RMA), especially on hemodynamics and left ventricular (LV) function in patients with functional mitral regurgitation (MR), have not been fully investigated.

METHODS AND RESULTS

From 1999 to 2008, 44 patients with refractory heart failure and functional MR underwent RMA with stringent downsizing of the mitral annulus. Serial echocardiography was performed to evaluate LV function (reverse remodeling), estimated systolic pulmonary artery pressure (PAP) and mitral valve geometry at baseline and at discharge, and annually thereafter. Cardiac catheterization was performed at baseline, and at discharge to evaluate acute hemodynamic change. There were 3 early deaths, and the 5-year survival rate was 78 ± 8%. In 41 survivors the clinical symptoms, stratified according to New York Heart Association class, significantly improved after surgery. Postoperative cardiac catheterization showed significant unloading for left ventricle, as well as improvement in LV systolic function. Serial echocardiography showed that improvements in LV function and systolic PAP were sustained in the majority of patients. Multivariate Cox regression analysis identified preoperative pulmonary hypertension (systolic PAP>60 mm Hg) as the significant predictor for postoperative adverse cardiac events.

CONCLUSIONS

RMA for functional MR resulted in sustained improvement of hemodynamics and LV function over time. Additional studies are needed to define the negative impact of preoperative pulmonary hypertension in patients with this condition.

Influence of patient age on procedural selection in mitral valve surgery

BACKGROUND

Previous studies suggest that mitral valve replacement is comparable to repair in the elderly, and a national trend exists toward tissue valves. However, few direct comparison data are available, and this study evaluated the effects of patient age on risk-adjusted survival after mitral procedures.

METHODS

From 1986 to 2006, 2,064 patients underwent isolated primary mitral operations (±CABG). Maximal follow-up was 20 years with a median of 5 years. Valve disease etiology was the following: degenerative, 864; ischemic, 450; rheumatic, 416; endocarditis, 98; and "other," 236. Overall, 58% had repair and 39% had concomitant coronary artery bypass grafting. Survival differences were evaluated with a Cox proportional hazards model that included baseline characteristics, valve disease etiology, and choice of repair versus replacement with tissue or mechanical valves.

RESULTS

Baseline risk profiles generally were better for mechanical valves, and age was the most significant multivariable predictor of late mortality [hazard ratio = 1.4 per 10-year increment, Wald χ(2) = 32.7, p < 0.0001]. As compared with repair, risk-adjusted survival was inferior with either tissue valves [1.8, 27.6, <0.0001] or mechanical valves [1.3, 8.1, 0.0044], and no treatment interaction was observed with age (p = 0.18). At no patient age did tissue valves achieve equivalent survival to either repair or mechanical valves.

CONCLUSIONS

Mitral repair is associated with better survival than valve replacement across the spectrum of patient age. If replacement is required, mechanical valves achieve better outcomes, even in the elderly. These data suggest that tissue valves should be reserved only for patients with absolute contraindications to anticoagulation who are not amenable to repair.

Mitral valve surgery in advanced heart failure

The appropriateness and timing of mitral valve surgery in patients with advanced heart failure and severe mitral regurgitation remains controversial. Recent surgical results provide evidence for beneficial effects on left ventricular remodeling and functional capacity. Given the absence of randomized trials comparing the outcomes of mitral valve surgery to medical therapy, however, clinical decision making regarding surgery for these fragile patients poses a dilemma to thoughtful clinicians. This paper reviews the pathophysiology of mitral regurgitation in heart failure and proposes an integrated approach to management.