Is mitral annuloplasty an effective treatment for severe atrial functional mitral regurgitation?

Functional Mitral Regurgitation and Heart Failure With Preserved Ejection Fraction: Clinical Implications and Management

Heart failure with preserved ejection fraction (HFpEF) is highly prevalent and associated with worse cardiovascular outcomes. The pathophysiology of HFpEF mostly relies on the development of elevated left ventricle filling pressure, diastolic dysfunction, and atrial dilatation and impairment. This dynamic process may eventually lead to the development of functional mitral regurgitation (MR), characterized by mitral annular dilatation and consequent leaflet remodeling, in the context of preserved left ventricular ejection fraction. These observations highlight the possible common pathophysiology of MR and HFpEF. However, less is known about the prevalence and the clinical value of MR in the context of HFpEF. This review aims to provide an overview of the association and interplay between functional MR and HFpEF, discuss the underlying mechanisms that are common to these diseases, and summarize potential targeted pharmacological treatments.

Outcome of mitral repair combined with Cox-maze procedure for atrial functional mitral regurgitation with heart failure with recovered ejection fraction

OBJECTIVES

Atrial functional mitral regurgitation (AFMR) in patients with heart failure with recovered ejection fraction has received insufficient attention. This study analysed the prognosis and outcomes of mitral valve (MV) repair combined with the Cox-maze procedure.

METHODS

A prospective cohort study of patients with AFMR with left ventricular ejection fraction (LVEF) <40% was conducted. All patients received guideline-directed medical therapy. Those with recovered ejection fraction underwent MV repair combined with the Cox-maze procedure. Mortality, atrial fibrillation (AF) recurrence, mitral regurgitation (MR) and postoperative tricuspid regurgitation were assessed using the inverse probability weighting (IPW) method.

RESULTS

In total, 312 patients were enrolled in this study between 2010 and 2019, 247 of whom underwent MV repair combined with the Cox-maze procedure [full recovery (LVEF > 50%): n = 132, partial recovery (LVEF of 40-50%): n = 115]. IPW-adjusted survival of patients with LVEF ≥50% and LVEF 40-50% showed no significant difference [hazard ratio (HR): 2.18, 95% confidence interval: 0.46-10.38, P = 0.33]. However, patients with LVEF ≥50% had better IPW-adjusted long-term freedom from recurrent MR [HR: 2.44 (1.28-4.63), P = 0.0065] and AF recurrence [HR: 1.85 (1.06-3.21), P = 0.030] than those with LVEF of 40-50%.

CONCLUSIONS

MV repair combined with the Cox-maze procedure was effective and feasible in patients with severe AFMR with heart failure with recovered ejection fraction. Additionally, patients with LVEF ≥50% after guideline-directed medical therapy undergoing these combined procedures had better long-term freedom from recurrent AF and MR than those with LVEF of 40-50%.

Incidence and causal association of functional atrial mitral regurgitation in HFpEF

Heart failure with preserved ejection fraction (HFpEF) is as common as heart failure with reduced ejection fraction. Atrial fibrillation (AF), as well as the presence of mitral regurgitation (MR), is highly prevalent in these patients. Atrial functional MR (AFMR) is a type of functional MR characterized by severe left atrial dilatation and remodeling with normal left ventricular (LV) dimensions and function. Dilatation of the mitral annulus is considered to be the main underlying mechanism, though the leaflets and the rest of the mitral apparatus play significant role in the development of MR, mainly in patients with long standing AF. There are several echocardiographic differences between atrial and ventricular functional MR, better identified with 3D echocardiography. Significant AFMR impairs prognosis, especially of patients with HFpEF, and this is important while they represent a group of under-diagnosed and under-treated patients. Finally, because focused medical evidence-based approach is not available yet, it seems that the prevention of left atrial dilatation and early restoration of sinus rhythm (SR) is the best therapeutic option.

Impact of secondary mitral regurgitation on survival in atrial and ventricular dysfunction

BACKGROUND

Natural history of atrial and ventricular secondary mitral regurgitation (SMR) is poorly understood. We compared the impact of the degree of SMR on survival between atrial and ventricular dysfunction.

METHODS

We conducted a retrospective cohort study of patients who underwent echocardiography in a healthcare network between 2013-2018. We compared the survival of patients with atrial and ventricular dysfunction, using propensity scores developed from differences in patient demographics and comorbidities within SMR severity strata (none, mild, moderate or severe). We fitted Cox proportional hazards models to estimate the risk-adjusted hazards of death across different severities of SMR between patients with atrial and ventricular dysfunction.

RESULTS

Of 11,987 patients included (median age 69 years [IQR 58-80]; 46% women), 6,254 (52%) had isolated atrial dysfunction, and 5,733 (48%) had ventricular dysfunction. 3,522 patients were matched from each arm using coarsened exact matching. Hazard of death in atrial dysfunction without SMR was comparable to ventricular dysfunction without SMR (HR 1.1, 95% CI 0.9-1.3). Using ventricular dysfunction without SMR as reference, hazards of death remained higher in ventricular dysfunction than in atrial dysfunction across increasing severities of SMR: mild SMR (HR 2.1, 95% CI 1.8-2.4 in ventricular dysfunction versus HR 1.7, 95%CI 1.5-2.0 in atrial dysfunction) and moderate/severe SMR (HR 2.8, 95%CI 2.4-3.4 versus HR 2.4, 95%CI 2.0-2.9).

CONCLUSIONS

SMR across all severities were associated with better survival in atrial dysfunction than in ventricular dysfunction, though the magnitude of the diminishing survival were similar between atrial and ventricular dysfunction in increasing severity of SMRs.

Pathophysiology, Echocardiographic Diagnosis, and Treatment of Atrial Functional Mitral Regurgitation: JACC State-of-the-Art Review

The conventional view holds that functional mitral regurgitation (MR) is caused by restriction of leaflet motion resulting from displacement of the papillary muscle-bearing segments of the left ventricle. In the past decade, evidence has accrued suggesting functional MR can also be caused by left atrial enlargement. This underrecognized cause of secondary MR-atrial functional MR (AF-MR)-is mechanistically linked to annular enlargement, perturbations of annular contraction, and atriogenic leaflet tethering. AF-MR has been described in patients with atrial fibrillation and heart failure with preserved ejection fraction. Preliminary data suggest rhythm control may decrease MR severity in patients with atrial fibrillation. Additionally, several studies have reported reductions in MR and symptomatic improvement with restrictive annuloplasty and transcatheter edge-to-edge repair. This review discusses the pathophysiology, echocardiographic diagnosis, and treatment of AF-MR. AF-tricuspid regurgitation is also discussed.

Posterior mitral leaflet augmentation with autologous pericardial patch for the surgical treatment of severe atrial functional mitral regurgitation

Atrial functional mitral regurgitation (MR) in patients with chronic atrial fibrillation has not been thoroughly discussed. Although there is insufficient evidence to surgically treat atrial functional MR, it is considered to be reasonable for those patients with severe atrial functional MR who have symptoms of heart failure despite adequate medical therapy. Herein, we report a useful technique for mitral valve repair using posterior mitral leaflet (PML) augmentation with autologous pericardium to obtain good mitral valve coaptation and eliminate atrial functional MR, including tethered PML, in a nonelderly patient.

Variable definitions and treatment approaches for atrial functional mitral regurgitation: A scoping review of the literature

OBJECTIVES

Atrial functional mitral regurgitation (AFMR) is a subtype of functional mitral regurgitation due to longstanding atrial fibrillation (AF) or heart failure with preserved ejection fraction. The variation in AFMR' definition and the common mode of treatment described in the literature remain unknown.

METHODS

We performed a scoping review of studies that surgically treated AFMR to characterize the existing variability in the definition of AFMR, the type of operations performed for AFMR valvulopathy, and the treatment for the chronic AF. We searched Medline, EMBASE, Cochrane Library, Scopus, and Web of Science since their inceptions for studies of patients affected by AFMR and surgically treated for their valvulopathy.

RESULTS

Twelve studies (n = 494 patients) met eligibility criteria. All studies excluded patients with signs of left ventricular (LV) dysfunction, but the way additional parameters were used to define AFMR at a more granular level varied across studies: nine studies (75%) used the presence of AF to define their AFMR cohorts, with five (41.2%) requiring a history of AF of >1 year; additionally, the threshold values for the LV ejection fraction differed (45%-55%). Isolated mitral annuloplasty was performed in 96.2% of patients. Broad variability was detected in the proportion of patients undergoing the Cox-Maze procedure (range, 17.8%-79.5%), pulmonary vein isolation (0.0%-66.7%), and left atrial appendage ligation (0.0%-100.0%).

CONCLUSIONS

AFMR remains variably defined in surgical studies, making comparisons across studies difficult. Mitral annuloplasty was most commonly performed. The proportion of AFMR patients undergoing concomitant procedures for AF varied substantially.