Importance of anterior leaflet tethering in predicting recurrence of ischemic mitral regurgitation after restrictive annuloplasty

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.

Meta-analysis of results of subvalvular repair for severe ischemic mitral regurgitation

BACKGROUND AND AIM OF THE STUDY

The aim of this meta-analysis was to compare short- and long-term outcomes of patients undergoing mitral annuloplasty (MA) with or without papillary muscle surgery (PMS) for the treatment of ischemic mitral regurgitation (IMR).

METHODS

A systematic review and meta-analysis in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement were performed.

RESULTS

Nine studies met the inclusion criteria. This meta-analysis identified 478 patients: 228 patients underwent MA alone and 250 patients underwent concomitant PMS. Early mortality was similar between two groups (odds ratio [OR] 1.14, 95% confidence interval [CI], 0.51-2.53; P = .75). PMS was associated at follow-up with a higher freedom from cardiac-related events (P = .050); moreover, although both surgical techniques had a positive impact on ventricular remodeling, the PMS group showed a significant higher reduction of left ventricle end-diastolic diameter (OR, 4.89, 95% CI, 2.77-7.01; P < .001) and left ventricle end-systolic diameter values (OR, 4.11, 95% CI, 1.98-6.24; P < .001). Finally, PMS compared with MA alone was associated with a significant reduction of recurrent mitral regurgitation at follow-up (OR, 3.25, 95% CI, 1.60-6.59; P = .001).

CONCLUSIONS

This meta-analysis demonstrated superiority in terms of ventricular remodeling of a combined approach encompassing PMS and MA over MA alone in IMR. Moreover, the association of subvalvular surgery with restrictive MA decreases the incidence of mitral regurgitation recurrence and cardiac-related events at follow-up.

The value of preoperative 3-dimensional over 2-dimensional valve analysis in predicting recurrent ischemic mitral regurgitation after mitral annuloplasty

OBJECTIVES

Repair for ischemic mitral regurgitation with undersized annuloplasty is characterized by high recurrence rates. We sought to determine the value of pre-repair 3-dimensional echocardiography over 2-dimensional echocardiography in predicting recurrence at 6 months.

METHODS

Intraoperative transesophageal 2-dimensional echocardiography and 3-dimensional echocardiography were performed in 50 patients undergoing undersized annuloplasty for ischemic mitral regurgitation. Two-dimensional echocardiography annular diameter and tethering parameters were measured in the apical 2- and 4-chamber views. A customized protocol was used to assess 3-dimensional annular geometry and regional leaflet tethering. Recurrence (grade ≥2) was assessed with 2-dimensional transthoracic echocardiography at 6 months.

RESULTS

Preoperative 2- and 3-dimensional annular geometry were similar in all patients with ischemic mitral regurgitation. Preoperative 2- and 3-dimensional leaflet tethering were significantly higher in patients with recurrence (n = 13) when compared with patients without recurrence (n = 37). Multivariate logistic regression revealed preoperative 2-dimensional echocardiography posterior tethering angle as an independent predictor of recurrence with an optimal cutoff value of 32.0° (area under the curve, 0.81; 95% confidence interval, 0.68-0.95; P = .002) and preoperative 3-dimensional echocardiography P3 tethering angle as an independent predictor of recurrence with an optimal cutoff value of 29.9° (area under the curve, 0.92; 95% confidence interval, 0.84-1.00; P < .001). The predictive value of the 3-dimensional geometric multivariate model can be augmented by adding basal aneurysm/dyskinesis (area under the curve, 0.94; 95% confidence interval, 0.87-1.00; P < .001).

CONCLUSIONS

Preoperative 3-dimensional echocardiography P3 tethering angle is a stronger predictor of ischemic mitral regurgitation recurrence after annuloplasty than preoperative 2-dimensional echocardiography posterior tethering angle, which is highly influenced by viewing plane. In patients with a preoperative P3 tethering angle of 29.9° or larger (especially when combined with basal aneurysm/dyskinesis), chordal-sparing valve replacement should be strongly considered.

Echocardiographic assessment of ischemic mitral regurgitation

Ischemic mitral regurgitation is an important consequence of LV remodeling after myocardial infarction. Echocardiographic diagnosis and assessment of ischemic mitral regurgitation are critical to gauge its adverse effects on prognosis and to attempt to tailor rational treatment strategy. There is no single approach to the echocardiographic assessment of ischemic mitral regurgitation: standard echocardiographic measures of mitral regurgitation severity and of LV dysfunction are complemented by assessments of displacement of the papillary muscles and quantitative indices of mitral valve deformation. Development of novel approaches to understand mitral valve geometry by echocardiography may improve understanding of the mechanism, clinical trajectory, and reparability of ischemic mitral regurgitation.

Subvalvular techniques to optimize surgical repair of ischemic mitral regurgitation

PURPOSE OF REVIEW

Surgical treatment of ischemic mitral regurgitation with reduction annuloplasty is the current standard of practice, yet recurrence rates approaching 30% limit the benefits of repair in this subset of patients. In an effort to improve outcomes, attention has turned to understanding the contribution of leaflet tethering in this disease process. Subvalvular techniques to alleviate leaflet restriction have recently been incorporated into methods of repair.

RECENT FINDINGS

Parameters of left ventricular remodeling have been quantified as risk factors for recurrence of mitral regurgitation following reduction annuloplasty. Papillary muscle relocation restores the physiologic configuration of the subvalvular apparatus, and results in significantly reduced rates of recurrent mitral regurgitation and adverse cardiac events over time. Secondary chordal cutting or reimplantation results in significantly increased leaflet mobility, decreased severity of recurrent mitral regurgitation, and improved reverse remodeling without adverse effect on left ventricular function.

SUMMARY

A superior repair with decreased recurrence of mitral regurgitation and enhanced reversal of left ventricular remodeling is possible when subvalvular techniques are combined with traditional ring annuloplasty. Further understanding of preoperative parameters that predict disease recurrence and inclusion of concomitant subvalvular techniques in this subset of patients will be the next major advance in this field.

Transventricular mitral valve repair in patients with acute forms of ischemic mitral regurgitation

Transventricular mitral valve surgery combined with left ventricular restoration avoids atriotomy and provides a larger operative field. We describe a series of 5 patients in whom we performed transventricular mitral valve repair by various techniques, such as band annuloplasty, papillary muscle reattachment, chordal cutting, and edge-to-edge repair. The more acute forms of ischemic mitral regurgitation, as found in our patients, can coexist with post-myocardial infarction contained rupture or post-myocardial infarction ventricular septal rupture. Because these patients already have an indication for ventriculotomy, concomitant transventricular repair of the mitral valve can render a separate atriotomy unnecessary and thereby shorten the duration of cardiopulmonary bypass. Moreover, in patients with acute presentations, the absence of atrial dilation (this last associated with chronic cases) might make transventricular repair a better choice than the more difficult atrial approach.

Management of severe ischemic cardiomyopathy: left ventricular assist device as destination therapy versus conventional bypass and mitral valve surgery

OBJECTIVES

Patients with severe ischemic cardiomyopathy (left ventricular ejection fraction <25%) and severe ischemic mitral regurgitation have a poor survival with medical therapy alone. Left ventricular assist device as destination therapy is reserved for patients who are too high risk for conventional surgery. We evaluated our outcomes with conventional surgery within this population and the comparative effectiveness of these 2 therapies.

METHODS

We identified patients who underwent conventional surgery or left ventricular assist device as destination therapy for severe ischemic cardiomyopathy (left ventricular ejection fraction <25%) and severe mitral regurgitation. The era for conventional surgery spanned from 1993 to 2009 and from 2007 to 2011 for left ventricular assist device as destination therapy. We compared baseline patient characteristics and outcomes in terms of end-organ function and survival.

RESULTS

A total of 88 patients were identified; 55 patients underwent conventional surgery (63%), and 33 patients (37%) received a left ventricular assist device as destination therapy. Patients who received left ventricular assist device as destination therapy had the increased prevalence of renal failure, inotrope dependency, and intra-aortic balloon support. Patients undergoing conventional surgery required longer ventilatory support, and patients receiving a left ventricular assist device required more reoperation for bleeding. Mortality rates were similar between the 2 groups at 30 days (7% in the conventional surgery group vs 3% in the left ventricular assist device as destination therapy group, P = .65) and at 1 year (22% in the conventional surgery group vs 15% in the left ventricular assist device as destination therapy group, P = .58). There was a trend toward improved survival in patients receiving a left ventricular assist device compared with the propensity-matched groups at 1 year (94% vs 71%, P = .171).

CONCLUSIONS

The operative mortality and early survival after conventional surgery seem to be acceptable. For inoperable or prohibitive-risk patients, left ventricular assist device as destination therapy can be offered with similar outcomes.

Recurrence of mitral regurgitation after partial versus complete mitral valve ring annuloplasty for functional mitral regurgitation

OBJECTIVES

Both partial and complete annuloplasty rings are used for mitral valve repair for patients with functional mitral regurgitation (FMR). We sought to determine if recurrence of mitral regurgitation (MR) is affected by the type of ring used.

METHODS

Five hundred forty-eight patients diagnosed with FMR underwent mitral valve repair with ring annuloplasty between 1998 and 2008 in our institution. Medical records were reviewed retrospectively for clinical and echocardiographic data to determine the presence of recurrent MR (defined as moderate or severe).

RESULTS

Among 479 patients for whom postoperative echocardiographic data were available, recurrent MR occurred less frequently in the complete versus partial ring group (20 of 209 [10%] vs 56 of 270 [21%] patients; P = .001), despite lower preoperative ejection fractions in the complete ring group (median, 35%; interquartile range, 25%-45% vs median, 40%; interquartile range, 30%-55%; P < .001). Kaplan-Meier analysis demonstrated greater freedom from recurrent MR in the complete ring group (108 vs 103 months; P = .001). Risk-matched propensity analysis of 102 patients per group (area under the curve, 0.824; 95% confidence interval, 0.788-0.861; P < .001) also demonstrated that complete ring recipients had greater freedom from recurrent MR than partial ring recipients by univariate analysis (7 [7%] vs 17 [17%] patients; P = .049), and a trend toward greater freedom by Kaplan-Meier analysis (110 vs 104 months; P = .068).

CONCLUSIONS

The use of complete mitral annuloplasty rings provides improved freedom from recurrent MR in patients with FMR.