Increasing Disadvantage of “Watchful Waiting” for Repairing Degenerative Mitral Valve Disease

The Role of Global Longitudinal Strain in the Follow-Up of Asymptomatic Patients with Chronic Primary Mitral Regurgitation

Background/Objectives: In patients with chronic primary mitral regurgitation (MR), postoperative persistent left ventricular (LV) dysfunction underlines the lack of a sensitive parameter that can identify subclinical LV dysfunction and optimize the timing of intervention. Left ventricular global longitudinal strain (LV-GLS) is a measure of the longitudinal left ventricular systolic function, with prognostic significance. Its role in the follow-up of asymptomatic patients with MR is, however, poorly defined. The aim of this study was to assess the relative changes in LV-GLS in a cohort of MR patients and to correlate these changes with the need for intervention during a follow-up period. Methods: We conducted a prospective study on a cohort of 218 patients, divided into three subgroups according to MR severity (mild, moderate, severe). LV-GLS was measured at baseline and every six months during a median follow-up period of 30 months. The composite endpoint was the occurrence of heart failure symptoms, hospitalization for heart failure, LVEF < 60%, LVEDD > 45 mm, new onset atrial fibrillation, or cardiovascular death. Results: Patients with moderate and severe MR had a significantly lower GLS at baseline than those with mild MR (19.5% and 19.1% versus 22.3%, p < 0.01) despite a normal LVEF in all subgroups. The relative decrease in LV-GLS occurred earlier (at 12 months vs. 24 months) and was more evident in patients with moderate and severe MR (13.6% and 14.5%, respectively) versus patients with mild MR (6.72%). The baseline LV-GLS being under 18% and a relative decrease of over 10% in GLS were independent predictors of a composite outcome (HR = 1.59, CI 95% 1.17-2.86; HR = 1.74, CI 95% 1.2-2.91, p < 0.01). Conclusions: LV-GLS is a valuable monitoring tool for asymptomatic MR patients, a relative decrease > 10% in GLS may be predictive for the need for valve intervention.

Advances in Mitral Valve Repair for Degenerative Mitral Regurgitation: Philosophy, Technical Details, and Long-Term Results

Degenerative mitral valve disease represents the most common cause of mitral regurgitation in industrialized countries. When left untreated, patients with severe degenerative mitral regurgitation show a poor clinical outcome. Conversely, a timely and appropriate correction provides a restored life expectancy and a good quality of life. Therefore, in this scenario, surgical mitral valve repair represents the gold standard of treatment. This review aims to analyze the indications, timing, and contemporary surgical techniques of mitral valve repair for degenerative mitral regurgitation. Moreover, the value of heart team approach and centers of excellence for mitral valve repair are also deeply discussed.

Current status of the treatment of degenerative mitral valve regurgitation

Degenerative mitral valve disease (myxomatous degeneration or fibroelastic deficiency) is the most common indication for surgical referral to treat mitral regurgitation. Mitral valve repair is the procedure of choice whenever feasible and when the results are expected to be durable. Posterior leaflet prolapse is the commonest lesion, found in up to two-thirds of patients. It is the easiest to repair, particularly when limited to one segment. In these cases, rates of repairability and procedural success approach 100%, and there is now ample evidence that the immediate and long-term results are better than those of valve replacement. Notably, minimally invasive valvular procedures, surgical or interventional, have attracted increasing interest in the last decade. When performed by experienced groups, mitral valve repair is unrivaled irrespective of the severity of lesions, from simple to complex, which leaflets are involved, and the type of degenerative involvement (myxomatous or fibroelastic). Its results should be viewed as the benchmark for other present and future technologies. By contrast, percutaneous mitral valve repair is still in its infancy and its results so far fall short of those of surgical repair. Nevertheless, continued investment in transcatheter procedures is of great importance to enable development and improved accessibility, particularly for patients who are considered unsuitable for surgery. In this review, we analyze the current status of management of degenerative mitral valve disease, discussing mitral valve anatomy and pathology, indications for intervention, and current surgical and transcatheter mitral valve procedures and results.

Mitral valve repair for degenerative mitral regurgitation in patients with left ventricular systolic dysfunction: early and mid-term outcomes

BACKGROUND

This study aims to evaluate the early and mid-term outcomes of mitral valve repair for degenerative mitral regurgitation (MR) in patients with left ventricular systolic dysfunction.

METHODS

From January 2005 to December 2016, the profiles of patients with degenerative MR who underwent mitral valve repair at our institution were analyzed. Left ventricular systolic dysfunction was defined as an ejection fraction < 60% or left ventricular end-systolic dimension > 40 mm. Finally, 322 patients with left ventricular systolic dysfunction were included in this study. The prognosis of left ventricular function during follow-up was evaluated and preoperative factors associated with deteriorated left ventricular systolic function during follow-up were analyzed.

RESULTS

The in-hospital mortality rate was 1.6%. The rate of eight-year overall survival, freedom from reoperation for mitral valve and freedom from recurrent MR were 96.9, 91.2 and 73.4%, respectively. Intraoperative residual mild MR (hazard ratio 4.82) and an isolated anterior leaflet lesion (hazard ratio 2.48) were independent predictive factors for recurrent MR. During follow-up, 212 patients underwent echocardiography examinations at our institution. Among them, 132 patients had improved left ventricular systolic function, and 80 patients had deteriorated left ventricular systolic. Freedom from recurrent MR was found in 75.9% of the improved left ventricular systolic function group and 56.2% of the deteriorated left ventricular systolic function group (P = 0.047). An age > 50 years (odds ratio 2.40), ejection fraction≤52% (odds ratio 2.79) and left ventricular end-systolic dimension≥45 mm (odds ratio 2.31) were independent risk factors for deteriorated left ventricular systolic function during follow-up.

CONCLUSIONS

Mitral valve repair could be safely performed for degenerative MR in patients with left ventricular systolic dysfunction. Intraoperative residual mild MR and an isolated anterior leaflet lesion were independent predictive factors for recurrent MR. An age > 50 years, ejection fraction≤52% and left ventricular end-systolic dimension≥45 mm were independent risk factors for deteriorated left ventricular systolic function during follow-up.

Global Longitudinal Strain Predicts Survival and Left Ventricular Function After Mitral Valve Surgery: A Meta-analysis

The timing for surgical treatment in patients with primary organic severe mitral valve regurgitation and preserved left ventricular ejection fraction (LVEF) systolic is a challenge since it depends upon LV end systolic dimension and LVEF which may be late markers of LV dysfunction. Echocardiography is the most important tool in the diagnosis of mechanisms, etiology, severity, and hemodynamic consequences of mitral regurgitation. The global longitudinal strain (GLS), a new and sensitive method for the detection of LV dysfunction, might be a useful method for the evaluation of preclinical systolic dysfunction. Nevertheless, its role for predicting postoperative outcomes is not well established. A meta-analysis was performed to address the role of GLS in patients with severe mitral regurgitation and preserved LVEF who underwent mitral surgery. We included studies that compared outcomes according to preoperative GLS in regard to survival and postoperative LV function. We included 2358 patients enrolled in 8 studies. Patients with reduced GLS% had worse long term survival after mitral valve surgery (hazard ratio = 1.13, 95% confidence interval [CI]: 1.02-1.26). Patients with preoperatively reduced GLS% had lower LVEF after surgery (mean difference [MD] = -5.06%, 95% CI: -8.97-1.16%) and additionally, patients who presented postoperative LVEF dysfunction had worse preoperative GLS (MD = 4.33, 95% CI: 3.89-4.76). In patients with primary mitral regurgitation, preoperative GLS is a predictor for long term survival and postoperative LVEF. It is a useful parameter to be included when considering early surgery in patients with severe mitral regurgitation and normal LVEF.

Global longitudinal strain to predict left ventricular dysfunction in asymptomatic patients with severe mitral valve regurgitation: literature review

The optimal treatment strategy for asymptomatic patients with severe mitral valve regurgitation (MR) and preserved left ventricular (LV) function is challenging. This manuscript reviews the available literature on the value of left ventricular global longitudinal strain (LV-GLS) in predicting LV dysfunction after mitral valve surgery in these patients and discusses its current place in the treatment strategy. Studies were identified from Cochrane Library, SCOPUS, PubMed and Web of Science up to February 2018. The domain used was MR. The determinant was LV-GLS; other methods of deformation imaging were excluded. The examined outcome was LV dysfunction after surgery. A total of 144 articles were retrieved, of which 11 publications met the inclusion criteria, including a total of 2415 patients. Ten studies showed a significant correlation between preoperative LV-GLS and LV dysfunction postoperatively; one study reported a negative correlation. These studies suggest that LV-GLS is a predictor of LV dysfunction after surgery in asymptomatic patients with chronic MR. Hence, incorporation of LV-GLS for clinical decision-making in these patients might be of additional value. Further research is needed to confirm the role of LV-GLS in postoperative patients, and additionally in asymptomatic MR patients during a 'watchful waiting' strategy.

Left ventricular remodelling in chronic primary mitral regurgitation: implications for medical therapy

Surgical repair or replacement of the mitral valve is currently the only recommended therapy for severe primary mitral regurgitation. The chronic elevation of wall stress caused by the resulting volume overload leads to structural remodelling of the muscular, vascular and extracellular matrix components of the myocardium. These changes are initially compensatory but in the long term have detrimental effects, which ultimately result in heart failure. Understanding the changes that occur in the myocardium due to volume overload at the molecular and cellular level may lead to medical interventions, which potentially could delay or prevent the adverse left ventricular remodelling associated with primary mitral regurgitation. The pathophysiological changes involved in left ventricular remodelling in response to chronic primary mitral regurgitation and the evidence for potential medical therapy, in particular beta-adrenergic blockers, are the focus of this review.

Benefits of Early Surgery on Clinical Outcomes After Degenerative Mitral Valve Repair

BACKGROUND

This study aimed to evaluate the clinical trends of mitral valve repair for degenerative mitral regurgitation and the benefit of early surgical intervention on repair durability in a high-volume center.

METHODS

From January 2003 to December 2015, 1,903 consecutive patients with severe degenerative mitral regurgitation underwent mitral valve repair at our institution. The timing of surgical intervention was evaluated by guideline-related indications including symptoms, atrial fibrillation, left ventricular dysfunction, and pulmonary hypertension. Clinical outcomes and risk factors for recurrent mitral regurgitation were analyzed.

RESULTS

Over 13 years from 2003 to 2015, trends of preoperative characteristics demonstrated that the proportion of asymptomatic patients substantially increased. The 8-year overall survival, freedom from reoperation for mitral valve, and freedom from recurrent mitral regurgitation were 96%, 96%, and 85%, respectively. Ejection fraction less than 60%, left ventricular end-diastolic dimension greater than 60 mm, isolated anterior leaflet lesion, and intraoperative mild residual mitral regurgitation were independent predictive factors for recurrent mitral regurgitation. The incidence of recurrent mitral regurgitation was significantly lower in the early intervention group (3% versus 18%, p < 0.01). In subgroup analysis of asymptomatic patients, the incidence of recurrent mitral regurgitation was significantly lower in patients without guideline-related indications (3% versus 31%, p < 0.0001).

CONCLUSIONS

Early surgical intervention for severe degenerative mitral regurgitation before symptoms, atrial fibrillation, and ventricular dysfunction are associated with excellent clinical outcomes. Besides complexity of leaflet lesion and repair quality, surgical timing also significantly affects repair durability. Early surgical intervention should therefore be recommended to reduce recurrent mitral regurgitation.

Long-term results of mitral valve repair for severe mitral regurgitation in asymptomatic patients

BACKGROUND

In asymptomatic patients with severe degenerative mitral valve regurgitation (MR), early surgery is often performed in experienced centers. The patient- and valve-related results and the quality of life after surgery in these patients remain insufficiently explored.

METHODS

Between 1/2000 and 12/2015, 83 asymptomatic patients (mean age 56.6±12.6 years, 21 female) without any complications related to long-lasting MR underwent early surgery. Follow-up clinical and echocardiographic data and health-related quality of life assessment (SF-36) were studied and matched to the general population.

RESULTS

Repair rate was 100% and early mortality was 0%. Residual MR (≥grade 2+) was seen in 1 (1%) patient who underwent a successful re-repair while 4 (5%) patients needed permanent pacemaker implantation. At a median follow-up of 7.6 (IQR 4.1-11.9) years, 6 late deaths occurred. The 10-year overall survival rate was 91.5% (95% CI 84.2-98.8%) and was comparable to the general population. The health-related quality of life (84% complete) did not differ from the general population. One patient underwent late reintervention. Median echocardiography follow-up was 5.2 years (IQR 2.4-10.4; 98% complete). The 10-year freedom from recurrent MR rate (≥grade 2+) was 86.7% (95% CI 76.1-97.3%). The 10-year freedom from any atrial tachycardia rate was 68.7% (95% CI 55.2-82.2%) while 7 (8%) patients underwent late pacemaker implantation.

CONCLUSIONS

Early surgical intervention in asymptomatic patients with severe MR can be performed safely and restores normal life expectancy and quality of life. However, the frequency of late arrhythmias and pacemaker implantation is high and needs further evaluation.

Long-Term Results of Mitral Valve Repair

Introduction

Current guidelines state that patients with severe mitral regurgitation should be treated in reference centers with a high reparability rate, low mortality rate, and durable results.

Objective

To analyze our global experience with the treatment of organic mitral regurgitation from various etiologies operated in a single center.

Methods

We evaluated all surgically treated patients with organic mitral regurgitation from 2004-2017. Patients were evaluated clinically and by echocardiography every year. We determined early and late survival rates, valve related events and freedom from recurrent mitral regurgitation and tricuspid regurgitation. Valve failure was defined as any mitral regurgitation ≥ moderate degree or the need for reoperation for any reason.

Results

Out of 133 patients with organic mitral regurgitation, 125 (93.9%) were submitted to valve repair. Mean age was 57±15 years and 52 patients were males. The most common etiologies were degenerative disease (73 patients) and rheumatic disease (34 patients). Early mortality was 2.4% and late survival was 84.3% at 10 years, which are similar to the age- and gender-matched general population. Only two patients developed severe mitral regurgitation, and both were reoperated (95.6% at 10 years). Freedom from mitral valve failure was 84.5% at 10 years, with no difference between degenerative and rheumatic valves. Overall, late ≥ moderate tricuspid regurgitation was present in 34% of the patients, being more common in the rheumatic ones. The use of tricuspid annuloplasty abolished this complication.

Conclusion

We have demonstrated that mitral regurgitation due to organic mitral valve disease from various etiologies can be surgically treated with a high repair rate, low early mortality and long-term survival that are comparable to the matched general population. Concomitant treatment of atrial fibrillation and tricuspid valve may be important adjuncts to optimize long-term results.

Simple versus complex degenerative mitral valve disease

OBJECTIVES

At a center where surgeons favor mitral valve (MV) repair for all subsets of leaflet prolapse, we compared results of patients undergoing repair for simple versus complex degenerative MV disease.

METHODS

From January 1985 to January 2016, 6153 patients underwent primary isolated MV repair for degenerative disease, 3101 patients underwent primary isolated MV repair for simple disease (posterior prolapse), and 3052 patients underwent primary isolated MV repair for complex disease (anterior or bileaflet prolapse), based on preoperative echocardiographic images. Logistic regression analysis was used to generate propensity scores for risk-adjusted comparisons (n = 2065 matched pairs). Durability was assessed by longitudinal recurrence of mitral regurgitation and reoperation.

RESULTS

Compared with patients with simple disease, those undergoing repair of complex pathology were more likely to be younger and female (both P values < .0001) but with similar symptoms (P = .3). The most common repair technique was ring/band annuloplasty (3055/99% simple vs 3000/98% complex; P = .5), followed by leaflet resection (2802/90% simple vs 2249/74% complex; P < .0001). Among propensity-matched patients, recurrence of severe mitral regurgitation 10 years after repair was 6.2% for simple pathology versus 11% for complex pathology (P = .007), reoperation at 18 years was 6.3% for simple pathology versus 11% for complex pathology, and 20-year survival was 62% for simple pathology versus 61% for complex pathology (P = .6).

CONCLUSIONS

Early surgical intervention has become more common in patients with degenerative MV disease, regardless of valve prolapse complexity or symptom status. Valve repair was associated with similarly low operative risk and time-related survival but less durability in complex disease. Lifelong annual echocardiographic surveillance after MV repair is recommended, particularly in patients with complex disease.

Synergistic Utility of Brain Natriuretic Peptide and Left Ventricular Global Longitudinal Strain in Asymptomatic Patients With Significant Primary Mitral Regurgitation and Preserved Systolic Function Undergoing Mitral Valve Surgery

Background—

In asymptomatic patients with ≥3+ mitral regurgitation and preserved left ventricular (LV) ejection fraction who underwent mitral valve surgery, we sought to discover whether baseline LV global longitudinal strain (LV-GLS) and brain natriuretic peptide provided incremental prognostic utility.

Methods and Results—

Four hundred and forty-eight asymptomatic patients (61±12 years and 69% men) with ≥3+ primary mitral regurgitation and preserved left ventricular ejection fraction, who underwent mitral valve surgery (92% repair) at our center between 2005 and 2008, were studied. Baseline clinical and echocardiographic data (including LV-GLS using Velocity Vector Imaging, Siemens, PA) were recorded. The Society of Thoracic Surgeons score was calculated. The primary outcome was death. Mean Society of Thoracic Surgeons score, left ventricular ejection fraction, mitral effective regurgitant orifice, indexed LV end-diastolic volume, and right ventricular systolic pressure were 4±1%, 62±3%, 0.55±0.2 cm 2 , 58±13 cc/m 2 , and 37±15 mm Hg, respectively. Forty-five percent of patients had flail. Median log-transformed BNP and LV-GLS were 4.04 (absolute brain natriuretic peptide: 60 pg/dL) and −20.7%. At 7.7±2 years, death occurred in 41 patients (9%; 0% at 30 days). On Cox analysis, a higher Society of Thoracic Surgeons score (hazard ratio 1.55), higher baseline right ventricular systolic pressure (hazard ratio 1.11), more abnormal LV-GLS (hazard ratio 1.17), and higher median log-transformed BNP (hazard ratio 2.26) were associated with worse longer-term survival (all P <0.01). Addition of LV-GLS and median log-transformed BNP to a clinical model (Society of Thoracic Surgeons score and baseline right ventricular systolic pressure) provided incremental prognostic utility (χ 2 for longer-term mortality increased from 31–47 to 61; P <0.001).

Conclusions—

In asymptomatic patients with significant primary mitral regurgitation and preserved left ventricular ejection fraction who underwent mitral valve surgery, brain natriuretic peptide and LV-GLS provided synergistic risk stratification, independent of established factors.

Cardiac surgery 2015 reviewed

For the year 2015, almost 19,000 published references can be found in PubMed when entering the search term "cardiac surgery". The last year has been again characterized by lively discussions in the fields where classic cardiac surgery and modern interventional techniques overlap. Lacking evidence in the field of coronary revascularization with either percutaneous coronary intervention or bypass surgery has been added. As in the years before, CABG remains the gold standard for the revascularization of complex stable triple-vessel disease. Plenty of new information has been presented comparing the conventional to transcatheter aortic valve implantation (TAVI) demonstrating similar short- and mid-term outcomes at high and low risk, but even a survival advantage with transfemoral TAVI at intermediate risk. In addition, there were many relevant and interesting other contributions from the purely operative arena. This review article will summarize the most pertinent publications in the fields of coronary revascularization, surgical treatment of valve disease, heart failure (i.e., transplantation and ventricular assist devices), and aortic surgery. While the article does not have the expectation of being complete and cannot be free of individual interpretation, it provides a condensed summary that is intended to give the reader "solid ground" for up-to-date decision-making in cardiac surgery.

Year in review: mitral valve surgery

PURPOSE OF REVIEW

In the past year, there has been progress on several fronts in the field of mitral valve surgery and intervention. Here, we review key publications regarding the surgical and transcatheter management of mitral valve disease.

RECENT FINDINGS

This past year heralded the publication of the 2014 American Heart Association (AHA)/American College of Cardiology (ACC) Guidelines for the Management of Patients With Valvular Heart Disease. Regarding degenerative mitral regurgitation, low risk of operative mortality and data demonstrating clinical benefit for early surgery are prompting renewed calls for early intervention before guideline-based triggers. For functional mitral regurgitation, the precise roles of chordal-sparing replacement versus repair and the optimal management of moderate disease at the time of surgical revascularization are unclear. Sternal-sparing minimally invasive mitral valve surgery has become a mature procedure in experienced centers and offers comparable surgical morbidity and mortality with superior cosmesis and faster return to baseline function. Transcatheter interventions for mitral regurgitation continue to undergo development and testing. Mounting experience and ongoing clinical trials with the MitraClip endovascular edge-to-edge repair device will provide important data on the optimal target population for this device.

SUMMARY

This past year has seen important advances in the surgical treatment of degenerative and functional mitral regurgitation as well as continued refinement of transcatheter interventions.