Mitral regurgitation and cardiac resynchronization therapy

Evolution and prognosis of tricuspid and mitral regurgitation following cardiac implantable electronic devices: a systematic review and meta-analysis

AIMS

Significant changes in tricuspid regurgitation (TR) and mitral regurgitation (MR) post-cardiac implantable electronic devices (CIEDs) are increasingly recognized. However, uncertainty remains as to whether the risk of CIED-associated TR and MR differs with right ventricular pacing (RVP) via CIED with trans-tricuspid RV leads, compared with cardiac resynchronization therapy (CRT), conduction system pacing (CSP), and leadless pacing (LP). The study aims to synthesize extant data on risk and prognosis of significant post-CIED TR and MR across pacing strategies.

METHODS AND RESULTS

We searched PubMed, EMBASE, and Cochrane Library databases published until 31 October 2023. Significant post-CIED TR and MR were defined as ≥ moderate. Fifty-seven TR studies (n = 13 723 patients) and 90 MR studies (n = 14 387 patients) were included. For all CIED, the risk of post-CIED TR increased [pooled odds ratio (OR) = 2.46 and 95% CI = 1.88-3.22], while the risk of post-CIED MR reduced (OR = 0.74, 95% CI = 0.58-0.94) after 12 and 6 months of median follow-up, respectively. Right ventricular pacing via CIED with trans-tricuspid RV leads was associated with increased risk of post-CIED TR (OR = 4.54, 95% CI = 3.14-6.57) and post-CIED MR (OR = 2.24, 95% CI = 1.18-4.26). Binarily, CSP did not alter TR risk (OR = 0.37, 95% CI = 0.13-1.02), but significantly reduced MR (OR = 0.15, 95% CI = 0.03-0.62). Cardiac resynchronization therapy did not significantly change TR risk (OR = 1.09, 95% CI = 0.55-2.17), but significantly reduced MR with prevalence pre-CRT of 43%, decreasing post-CRT to 22% (OR = 0.49, 95% CI = 0.40-0.61). There was no significant association of LP with post-CIED TR (OR = 1.15, 95% CI = 0.83-1.59) or MR (OR = 1.31, 95% CI = 0.72-2.39). Cardiac implantable electronic device-associated TR was independently predictive of all-cause mortality [pooled hazard ratio (HR) = 1.64, 95% CI = 1.40-1.90] after median of 53 months. Mitral regurgitation persisting post-CRT independently predicted all-cause mortality (HR = 2.00, 95% CI = 1.57-2.55) after 38 months.

CONCLUSION

Our findings suggest that, when possible, adoption of pacing strategies that avoid isolated trans-tricuspid RV leads may be beneficial in preventing incident or deteriorating atrioventricular valvular regurgitation and might reduce mortality.

Persistence of significant secondary mitral regurgitation post-cardiac resynchronization therapy and survival: a systematic review and meta-analysis : Mitral regurgitation and mortality post-CRT

Cardiac resynchronization therapy (CRT) significantly reduces secondary mitral regurgitation (MR) in patients with severe left ventricular systolic dysfunction. However, uncertainty remains as to whether improvement in secondary MR correlates with improvement with mortality seen in CRT. We conducted a meta-analysis to determine the association of persistent unimproved significant secondary MR (defined as moderate or moderate-to-severe or severe MR) compared to improved MR (no MR or mild MR) post-CRT with all-cause mortality, cardiovascular mortality, and heart failure hospitalization. A systematic search of PubMed, EMBASE, and Cochrane Library databases till July 31, 2022 identified studies reporting clinical outcomes by post-CRT secondary MR status. In 12 prospective studies of 4954 patients (weighted mean age 66.8 years, men 77.8%), the median duration of follow-up post-CRT at which patients were re-evaluated for significant secondary MR was 6 months and showed significant relative risk reduction of 30% compared to pre-CRT. The median duration of follow-up post-CRT for ascertainment of main clinical outcomes was 38 months. The random effects pooled hazard ratio (95% confidence interval) of all-cause mortality in patients with unimproved secondary MR compared to improved secondary MR was 2.00 (1.57-2.55); p < 0.001). There was insufficient data to evaluate secondary outcomes in a meta-analysis, but limited data that examined the relationship showed significant association of unimproved secondary MR with increased cardiovascular mortality and heart failure hospitalization. The findings of this meta-analysis suggest that lack of improvement in secondary MR post-CRT is associated with significantly elevated risk of all-cause mortality and possibly cardiovascular mortality and heart failure hospitalization. Future studies may investigate approaches to address persistent secondary MR post-CRT to help improved outcome in this population.

Medical Therapy for Functional Mitral Regurgitation

Functional mitral regurgitation (FMR) can be broadly categorized into 2 main groups: ventricular and atrial, which often coexist. The former is secondary to left ventricular remodeling usually in the setting of heart failure with reduced ejection fraction or less frequently due to ischemic papillary muscle remodeling. Atrial FMR develops due to atrial and annular dilatation related to atrial fibrillation/flutter or from increased atrial pressures in the setting of heart failure with preserved ejection fraction. Guideline-directed medical therapy is the first step and prevails as the mainstay in the treatment of FMR. In this review, we address the medical therapeutic options for FMR management and highlight a targeted approach for each FMR category. We further address important clinical and echocardiographic characteristics to aid in determining when medical therapy is expected to have a low yield and an appropriate window for effective interventional approaches exists.

Predictors of persistence of functional mitral regurgitation after cardiac resynchronization therapy: Review of literature

Functional mitral regurgitation is a common finding among heart failure patients with ischemic and non-ischemic dilated cardiomyopathies. The presence of moderate or severe mitral regurgitation is associated with higher morbidity and mortality. Heart failure patients meeting electrocardiogram and left ventricle function criteria are good candidates for cardiac resynchronization therapy, which may reduce the degree of functional mitral regurgitation in the short and long term, specifically targeting myocardial dyssynchrony and inducing left ventricle reverse remodeling. In this article, we analyze data from the literature about predictors of mitral regurgitation improvement after cardiac resynchronization therapy implantation.

Transcatheter Mitral Valve Repair in Patients With and Without Cardiac Resynchronization Therapy: The COAPT Trial

BACKGROUND

In the COAPT trial (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation), treatment of heart failure (HF) patients with moderate-severe or severe secondary mitral regurgitation with transcatheter mitral valve repair (TMVr) using the MitraClip plus guideline-directed medical therapy (GDMT) reduced 2-year rates of HF hospitalization and all-cause mortality compared with GDMT alone. Whether the benefits of the MitraClip extend to patients with previously implanted cardiac resynchronization therapy (CRT) is unknown. We sought to examine the effect of prior CRT in patients enrolled in COAPT.

METHODS

Patients (N=614) with moderate-severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated doses of GDMT were randomized 1:1 to the MitraClip (TMVr arm) versus GDMT only (control arm). Outcomes were assessed according to prior CRT use.

RESULTS

Among 614 patients, 224 (36.5%) had prior CRT (115 and 109 randomized to TMVr and control, respectively) and 390 (63.5%) had no CRT (187 and 203 randomized to TMVr and control, respectively). Patients with CRT had similar 2-year rates of the composite of death or HF hospitalization compared with those without CRT (57.6% versus 55%, P=0.32). Death or HF hospitalization at 2 years was lower with TMVr versus control treatment in patients with prior CRT (48.6% versus 67.2%, hazard ratio, 0.60 [95% CI, 0.42-0.86]) and without CRT (42.5% versus 66.9%, hazard ratio, 0.52 [95% CI, 0.39-0.69]; adjusted P_interaction=0.23). The effects of TMVr with the MitraClip on reducing the 2-year rates of all-cause death (adjusted P_interaction=0.14) and HF hospitalization (adjusted P_interaction=0.82) were also consistent in patients with and without CRT as were improvements in quality-of-life and exercise capacity.

CONCLUSIONS

In the COAPT trial, TMVr with the MitraClip improved the 2-year prognosis of patients with HF and moderate-severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated GDMT, regardless of prior CRT implantation. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01626079.

The effects of cardiac resynchronization therapy on left ventricular and mitral valve geometry and secondary mitral regurgitation in patients with left bundle branch block

BACKGROUND

Secondary mitral regurgitation (MR) is common in patients with left bundle branch block (LBBB) undergoing cardiac resynchronization therapy (CRT). We aimed to define CRT effects on left ventricular (LV) and mitral valve (MV) geometry, and their correlation with MR severity.

METHODS

Forty-one patients with LBBB and ≥mild secondary MR underwent CRT between 2009 and 2012, and had baseline and follow-up echocardiograms available. Repeated measure and linear regression analyses were performed to assess for changes in MV and LV geometry and MR severity, and associations with follow-up MR grade.

RESULTS

The mean age and baseline QRS duration were 65.5 ± 14.9 years and 160 ± 24 ms. At a mean follow-up of 2.6 ± 1.8 years, there was an increase in LV ejection fraction and reductions in LV end-systolic volume index, MR grade, and end-systolic interpapillary muscle distance (P < .05 for all). Linear correlations were observed between follow-up MR grade and baseline MV tenting height (r = .44), left atrial volume index (r = .41), LV end-systolic volume index (r = .4), MV tenting area (r = .38), LV ejection fraction (r = -.34), and end-systolic interpapillary muscle distance (r = .34) (P < .05 for all). Multiple regression analysis revealed associations between follow-up MR grade and baseline MV tenting height (β/mm = 0.42, P = .006) and left atrial volume index (β/mL/m2  = 0.4, P = .008), independent of QRS duration (β/ms=-0.07; P = 0.6) and nonischemic cardiomyopathy (β = -0.34, P = .02).

CONCLUSIONS

Cardiac resynchronization therapy in patients with LBBB and secondary MR results in LV and MV geometric reverse remodeling and decreases MR severity. Extent of baseline MV tethering is independently associated with persistent MR at follow-up.

Therapeutic options for functional mitral regurgitation in chronic heart failure

INTRODUCTION

Mitral regurgitation is a common finding in patients with chronic heart failure and is associated with a progressive worsening of symptoms, reduced survival and increased cost of care. However, the use of mitral valve surgery for these patients remains controversial and has not been shown to improve survival. Consequently, research has been increasingly directed towards the nonsurgical management of this important co-morbidity of heart failure.

AREAS COVERED

The present review will describe the relevance of mitral regurgitation in people with chronic heart failure, the current options for percutaneous treatment and the evidence base for each of these.

EXPERT COMMENTARY

Although at present there are few solid data to guide heart teams in deciding what degree of mitral regurgitation to treat, in which patients, and with what, this situation is likely to change over the next two years with the release of the first large randomised trials of percutaneous interventions.

Ventricular pacing - Electromechanical consequences and valvular function

Although great strides have been made in the areas of ventricular pacing, it is still appreciated that dyssynchrony can be malignant, and that appropriately placed pacing leads may ameliorate mechanical dyssynchrony. However, the unknowns at present include: 1. The mechanisms by which ventricular pacing itself can induce dyssynchrony; 2. Whether or not various pacing locations can decrease the deleterious effects caused by ventricular pacing; 3. The impact of novel methods of pacing, such as atrioventricular septal, lead-less, and far-field surface stimulation; 4. The utility of ECG and echocardiography in predicting response to therapy and/or development of dyssynchrony in the setting of cardiac resynchronization therapy (CRT) lead placement; 5. The impact of ventricular pacing-induced dyssynchrony on valvular function, and how lead position correlates to potential improvement. This review examines the existing literature to put these issues into context, to provide a basis for understanding how electrical, mechanical, and functional aspects of the heart can be distorted with ventricular pacing. We highlight the central role of the mitral valve and its function as it relates to pacing strategies, especially in the setting of CRT. We also provide future directions for improved pacing modalities via alternative pacing sites and speculate over mechanisms on how lead position may affect the critical function of the mitral valve and thus overall efficacy of CRT.

Mechanical dyssynchrony and deformation imaging in patients with functional mitral regurgitation

Chronic functional mitral regurgitation (FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy (DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle (LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy (CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.

Effect of QRS Narrowing After Cardiac Resynchronization Therapy on Functional Mitral Regurgitation in Patients With Systolic Heart Failure

The determinants of improvement in functional mitral regurgitation (FMR) after cardiac resynchronization therapy (CRT) remain unclear. We evaluated the predictors of FMR improvement and hypothesized that CRT-induced change in QRS duration (ΔQRS) might have an impact on FMR response after CRT. One hundred ten CRT recipients were enrolled. CRT response (≥ 15 reduction in left ventricular end-systolic volume) and FMR response (absolute reduction in FMR volume) were assessed with echocardiography before and 6 months after CRT. The study end points included all-cause death or hospitalization assessed in 12 ± 3 months (range 1 to 18). A total of 71 patients (65%) responded to CRT at 6 months. FMR response was observed in 49 (69%) of the CRT responders and 8 (20%) of the CRT nonresponders (p <0.001). Although the baseline QRS durations were similar, the paced QRS durations were shorter (p = 0.012) and the ΔQRS values were greater (p = 0.003) in FMR responders compared with FMR nonresponders. There was a linear correlation between ΔQRS and change in regurgitant volume (r = 0.49, p <0.001). At multivariate analysis, baseline tenting area (p = 0.012) and ΔQRS (p = 0.028) independently predicted FMR response. A ΔQRS ≥ 20 ms was related to CRT response, FMR improvement, and lower rates of death or hospitalization during follow-up (p values <0.05). In conclusion, QRS narrowing after CRT independently predicts FMR response. A ΔQRS ≥ 20 ms after CRT is associated with a favorable outcome in all clinical end points.

Cardiac Resynchronisation Therapy or MitraClip® Implantation for Patients with Severe Mitral Regurgitation and Left Bundle Branch Block?

Secondary or functional mitral regurgitation (FMR) is a common problem in patients with chronic heart failure (HF). About one-third of patients with chronic HF also have left bundle branch block (LBBB). Approximately one-third of patients with an indication for cardiac resynchronisation therapy (CRT) have moderate-to-severe FMR. This FMR may either be a consequence of systolic dysfunction or it may occur due to dyssynchrony. Both directly reducing FMR and correcting cardiac dyssynchrony are viable therapeutic approaches in selected patients, according to the 2012 European Society of Cardiology (ESC) Guidelines for valvular heart disease. Initial presence of FMR is an independent predictor of lack of clinical response to CRT. Patients undergoing CRT without signs of significant clinical improvement may be considered candidates for the percutaneous MitraClip® procedure. As yet, there are not enough data to select patients that would benefit from being treated primarily with MitraClip. A clinical trial in HF patients to be randomised to either MitraClip procedure or CRT is needed to confirm actual ESC Guideline therapy.

How to improve outcomes: should we put more emphasis on programming and medical care and less on patient selection?

Many factors contribute to the pathophysiology and progression of heart failure (HF), offering the potential for many synergistic therapeutic approaches to its management. For patients, who have systolic HF, prolonged QRS and receiving guideline-indicated pharmacological therapy, cardiac resynchronization therapy (CRT) may provide additional benefits in terms of symptom improvement and mortality reduction. Nevertheless, in many patients, moderate or severe symptoms may persist or recur after CRT implantation due to either the severity or progression of the underlying disease, the presence of important co-morbidities or suboptimal device programming. Identifying and, where possible, treating the reasons for persistent or recurrent symptoms in patients who have received CRT is an important aspect of patient care. The present review summarizes the available evidence on this topic.

Clinical implication of mechanical dyssynchrony in heart failure

Mechanical dyssynchrony is a common phenomenon in patients with congestive heart failure, which usually identified by noninvasive cardiac imaging tools such as echocardiography. It demonstrates electromechanical delay in some regions of the failing heart which in turn contributes to further impairment of cardiac function. The diagnostic, therapeutic and prognostic values of mechanical dyssynchrony have been reported in a number of studies. Therefore, this review describes briefly the methods of measurement, but more importantly, explains the clinical implication of its assessment in heart failure related aspects including cardiac resynchronization therapy, functional mitral regurgitation, diastolic heart failure and mortality.

Ischemic mitral regurgitation: pathophysiology, diagnosis, and treatment

Secondary or 'functional' mitral regurgitation (MR) is often due to ischemic heart disease that results in disordered left ventricle and mitral valve geometry. In patients with coronary disease, concomitant MR results in worse morbidity and mortality. Coronary artery disease may result in annular dilation due to left ventricle cavity dilation, excessive leaflet motion, impaired leaflet motion due to leaflet tethering and papillary muscle displacement, and/or decreased mitral valve closing forces due to systolic dysfunction. Although transthoracic echocardiography is the first step in the diagnosis of ischemic MR, transesophageal and three-dimensional echocardiography are often useful adjuncts to better understand the mechanism(s) of disease and planning repair. Furthermore, noninvasive evaluation of ischemia and viability may provide important prognostic information. Medical therapy for ischemic MR is directed at the underlying ischemic substrate and concomitant systolic dysfunction, and consists of β-blockers and vasodilators. Percutaneous strategies for repair are currently under investigation, and have shown promising results. Surgical repair is favored over replacement, and is generally recommended for patients with moderate or severe MR undergoing coronary artery bypass. Unfortunately, long-term freedom from MR is elusive even with surgical repair, and trials are currently underway to determine the best approach to treatment in patients with moderate disease.

Cardiac Resynchronization Therapy as a Therapeutic Option in Patients With Moderate-Severe Functional Mitral Regurgitation and High Operative Risk

Background—

Functional mitral regurgitation (MR) is a common finding in heart failure patients with dilated cardiomyopathy and has important prognostic implications. However, the increased operative risk of these patients may result in low referral or high denial rate for mitral valve surgery. Cardiac resynchronization therapy (CRT) has been shown to have a favorable effect on MR. Aims of this study were to (1) evaluate CRT as a therapeutic option in heart failure patients with functional MR and high operative risk and (2) investigate the effect of MR improvement after CRT on prognosis.

Methods and Results—

A total of 98 consecutive patients with moderate-severe functional MR and high operative risk underwent CRT according to current guidelines. Echocardiography was performed at baseline and 6-month follow-up; severity of MR was graded according to a multiparametric approach. Significant improvement of MR was defined as a reduction ≥1 grade. All-cause mortality was assessed during follow-up (median 32 [range 6.0 to 116] months). Thirteen patients (13%) died before 6-months follow-up. In the remaining 85 patients, significant reduction in MR was observed in all evaluated parameters. In particular, 42 patients (49%) improved ≥1 grade of MR and were considered MR improvers. Survival was superior in MR improvers compared to MR nonimprovers (log rank P <0.001). Mitral regurgitation improvement was an independent prognostic factor for survival (hazard ratio 0.35, confidence interval 0.13 to 0.94; P =0.043).

Conclusions—

Cardiac resynchronization therapy is a potential therapeutic option in heart failure patients with moderate-severe functional MR and high risk for surgery. Improvement in MR results in superior survival after CRT.

The importance of papillary muscle dyssynchrony in predicting the severity of functional mitral regurgitation in patients with non-ischaemic dilated cardiomyopathy: a two-dimensional speckle-tracking echocardiography study

AIMS

In our study, we investigated the impact of papillary muscle systolic dyssynchrony (DYS-PAP) and the configuration of mitral leaflets in the prediction of significant functional mitral regurgitation (MR) with two-dimensional (2D) speckle-tracking strain analysis in non-ischaemic dilated cardiomyopathy (DCM) patients with sinus rhythm.

METHODS

Thirty-six non-ischaemic DCM patients (left ventricular ejection fraction <40%) with sinus rhythm were recruited. The quantification of functional MR was performed using the proximal isovelocity surface area method. The configuration of mitral leaflets [mitral annulus, coaptation height (CH), and tethering distances for papillary muscles] was evaluated in the parasternal long-axis and apical four-chamber views. The assessment of DYS-PAP was performed by applying 2D speckle-tracking imaging to the apical four-chamber view for anterolateral papillary muscle and to the apical long-axis view for posteromedial papillary muscle.

RESULTS

Fifteen (41.6%) patients had mild MR and 21 (58.3%) patients had moderate or moderate-to-severe MR. Patients with higher levels of MR had larger mitral annulus size (P = 0.02), tethering-AL (P = 0.04), higher MR volume (P < 0.0001), effective regurgitant orifice area (P < 0.0001), and DYS-PAP (P < 0.0001) values, but lower CH (P = 0.001), global longitudinal (P = 0.005), radial (P = 0.03), and circumferential strain (P = 0.01) than those with mild MR. Receiver operating characteristic analysis was performed to assess the utility of DYS-PAP to predict moderate or moderate-to-severe functional MR. A DYS-PAP value >30 ms predicted moderate-to-severe MR with 85% sensitivity and 87% specificity [area under the curve: 0.897, 95% confidence interval (CI): 0.781-0.999, P < 0.0001]. Logistic regression analysis revealed that DYS-PAP (odds ratio: 3.2, 95% CI: 1.22-47.7, P = 0.037) was the only independent predictor of moderate or moderate-to-severe functional MR.

CONCLUSION

DYS-PAP is correlated with functional MR in non-ischaemic DCM patients with sinus rhythm. A DYS-PAP cut-off value of 30 ms is a useful tool to identify patients with moderate-to-severe functional MR.

Impact of mitral regurgitation and myocardial viability on left ventricular reverse remodeling after cardiac resynchronization therapy in patients with ischemic cardiomyopathy

This study investigated the impact of ischemic mitral regurgitation (MR) severity and viability on left ventricular (LV) reverse remodeling after cardiac resynchronization therapy (CRT) in patients with ischemic cardiomyopathy. Severe MR and ischemic cardiomyopathy have been associated with lack of LV reverse remodeling after CRT. Fifty-seven consecutive patients with ischemic MR, LV ejection fraction < or =35%, QRS duration > or =120 ms, and intraventricular dyssynchrony > or =50 ms were prospectively included. Stress echocardiography was performed before CRT implantation. Viability in the region of the LV pacing lead was defined as the presence of viability in 2 contiguous segments. Response to CRT at 6 months was defined by evidence of > or =15% LV decrease in end-systolic volume. Severe MR was defined by an effective regurgitant orifice (ERO) area > or =20 mm(2). Thirty-three patients (58%) were responders at follow-up. Baseline ERO area and prevalence of severe MR were not different between responders and nonresponders (19 +/- 11 vs 21 +/- 13 mm(2), p = 0.67; 52% vs 53%, p = 0.84). In responders, MR was decreased by 58% (ERO 19 +/- 12 to 8 +/- 6 mm(2)). In the presence of viability in the region of the pacing lead, 74% (n = 29 patients) were responders (sensitivity 88%, specificity 58%); in the subgroup of patients with viability in the region of the pacing lead and severe MR, 83% (n = 17 patients) were responders. In conclusion, LV remodeling is frequent and ischemic MR decrease important in patients with viability in the region of the pacing lead without regard to MR severity.

Valvular regurgitation and stenosis: when is surgery required?

Valvular heart disease is a growing public health problem, with an increasing prevalence due to an ageing population. Despite advances, the medical management of symptomatic valvular heart diseases remains suboptimal, necessitating surgical correction. The challenge remains in identifying an asymptomatic or mildly symptomatic patient who will benefit from timely surgery before irreversible changes in cardiac function have occurred. The potential risks of surgery versus watchful expectancy require careful decision-making. This review is a focused update on the existing guidelines and identifies the knowledge gaps and avenues of future research in the management of patients with valvular heart diseases.