Effects of Transcatheter Mitral Valve Repair With MitraClip on Left Ventricular and Atrial Hemodynamic Load and Myocardial Wall Stress

Atrial Cardiomyopathy in Valvular Heart Disease: From Molecular Biology to Clinical Perspectives

This review discusses the evolving topic of atrial cardiomyopathy concerning valvular heart disease. The pathogenesis of atrial cardiomyopathy involves multiple factors, such as valvular disease leading to atrial structural and functional remodeling due to pressure and volume overload. Atrial enlargement and dysfunction can trigger atrial tachyarrhythmia. The complex interaction between valvular disease and atrial cardiomyopathy creates a vicious cycle of aggravating atrial enlargement, dysfunction, and valvular disease severity. Furthermore, atrial remodeling and arrhythmia can predispose to atrial thrombus formation and stroke. The underlying pathomechanism of atrial myopathy involves molecular, cellular, and subcellular alterations resulting in chronic inflammation, atrial fibrosis, and electrophysiological changes. Atrial dysfunction has emerged as an essential determinant of outcomes in valvular disease and heart failure. Despite its predictive value, the detection of atrial fibrosis and dysfunction is challenging and is not included in the clinical routine. Transthoracic echocardiography and cardiac magnetic resonance imaging are the main diagnostic tools for atrial cardiomyopathy. Recently published data have revealed that both left atrial volumes and functional parameters are independent predictors of cardiovascular events in valvular disease. The integration of atrial function assessment in clinical practice might help in early cardiovascular risk estimation, promoting early therapeutic intervention in valvular disease.

Effect of mitral valve transcatheter edge-to-edge repair on indices of left atrial performance in chronic mitral regurgitation

INTRODUCTION

Effect of transcatheter edge-to-edge repair (TEER) using MitraClip in patients with mitral regurgitation (MR) on left atrial (LA) kinetic energy (LAKE), an index of LA work, and LA strain, a measure of LA performance, have not been well defined.

METHODS

Patients with chronic primary or secondary 3+ or 4+ MR were analyzed pre- and post-TEER using MitraClip. LAKE was determined by echocardiography using LA stroke volume and A-wave velocity. Peak atrial longitudinal strain (PALS), peak atrial strain in early diastole, and peak atrial contraction strain (PACS) were obtained by speckle tracking echocardiography.

RESULTS

Thirty-nine patients undergoing TEER with MitraClip were screened, 12 met criteria for analysis (9 primary and 3 secondary MR). Compared to pre-TEER, there was a significant increase post-TEER in LAKE (71.0 ± 64.1 vs. 177.5 ± 167.9 dyne·cm·10³ , respectively; p = .008) and Doppler transmitral A-wave velocity (87.8 ± 41.4 vs. 138.5 ± 43.7 cm/s, respectively; p < .001); LA stroke volume did not change significantly. Mitral valve mean gradient significantly increased post-TEER compared to pre-TEER (5.7 ± 2.1 vs. 3.3 ± 2.1 mmHg, respectively; p = .01). There was a trend toward decrease in PALS post-TEER compared to pre-TEER (16.2 ± 4.8 vs. 20.7 ± 9.9%, respectively; p = .05). Peak atrial strain in early diastole significantly decreased post-TEER compared to pre-TEER (7.2 ± 3.0 vs. 14.1 ± 7.2%; respectively, p < .001), while PACS did not significantly change (9.1 ± 3.5 vs. 6.7 ± 5.2%, respectively; p = .07).

CONCLUSION

In patients with chronic MR, LAKE increases after TEER with MitraClip driven by an increase in LA emptying velocities. Changes were also seen in LA strain with MitraClip. These procedurally induced changes due to mild mitral stenosis may have clinical implications.

Acute effect of edge-to-edge repair of mitral regurgitation on left heart mechanics and health status

AIMS

Examine the impact of acute changes in left heart strain and volumes with percutaneous edge-to-edge MitraClip repair on improvement in health status assessed using Kansas City Cardiomyopathy Questionnaire-12 (KCCQ-12) score.

METHODS

Changes in left atrial strain, left ventricular (LV) global longitudinal strain (LVGLS), LV end-systolic volume (LVESV), and end-diastolic volume (LVEDV) were evaluated in 50 patients undergoing MitraClip repair for symptomatic primary mitral regurgitation (PMR) and secondary mitral regurgitation (SMR) on transthoracic echocardiography before and 1 month after MitraClip. Multivariable regression was used to evaluate changes in left heart strain and volumes as predictors of change in KCCQ-12 scores, adjusting for baseline clinical and echocardiographic characteristics.

RESULTS

Both PMR and SMR patients had significant increase in LVGLS and reduction in LVEDV and LVESV (P < 0.05) after MitraClip, reduction trend in left atrial conduit strain (PMR P = 0.053; SMR P = 0.12) but no significant change in LV ejection fraction. KCCQ-12 score improved significantly in both PMR (P < 0.001) and SMR cohorts (P < 0.001). Higher delta KCCQ-12 tertiles were associated with greater reduction in LVEDV (P = 0.022) after MitraClip. On multiple regression analysis, lower preprocedural Society of Thoracic Surgeons for Mitral Valve Replacement and KCCQ-12 score, and greater reduction in LVESV and left atrial strain conduit phase were associated with KCCQ-12 score improvement (P < 0.001).

CONCLUSION

There is a significant increase in LVGLS and reduction in LVEDV, LVESV and left atrial strain conduit after edge-to-edge MitraClip repair in both PMR and SMR. Lower preprocedural Society of Thoracic Surgeons for Mitral Valve Replacement and KCCQ-12 score, and greater reduction in LVESV and left atrial conduit strain were associated with KCCQ-12 score improvement after MitraClip. Further studies are warranted to understand the mechanism and significance of our findings.

Periprocedural changes in natriuretic peptide levels and clinical outcome after transcatheter mitral valve repair

Aims

This multicentre study investigated the association of periprocedural changes in the levels of N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) with clinical outcomes after transcatheter edge‐to‐edge mitral valve repair (TMVR).

Methods and results

Patients were retrospectively analysed who underwent TMVR with the MitraClip system (Abbott Vascular, Santa Clara, CA, USA) and had available sequential NT‐proBNP testing at baseline and 2 months after TMVR. Periprocedural changes in NT‐proBNP following TMVR were assessed as the percent change in NT‐proBNP between baseline and the 2 month follow‐up, and the significant reduction in NT‐proBNP was defined as a decrease of >30% in the follow‐up NT‐proBNP compared with the pre‐procedural NT‐proBNP level. Primary outcome was defined as a composite outcome consisting of all‐cause mortality and hospitalization due to heart failure from 2 months to 2 years after TMVR. Additionally, we identified the cut‐off value of pre‐procedural NT‐proBNP to predict the composite outcome using a receiver operating characteristic analysis (cut‐off: 2485 pg/mL). Of 485 patients undergoing TMVR (age: 76.2 ± 9.2 years, female: 42.1%, secondary mitral regurgitation: 67.2%), 150 patients (30.9%) had the significant reduction in NT‐proBNP (>30%) following the procedure. Patients with the NT‐proBNP reduction had a lower incidence of the composite outcome, compared with those without the reduction in NT‐proBNP (31.4% vs. 40.2%; log‐rank P = 0.03). The significant reduction in NT‐proBNP was also associated with a lower risk of the composite outcome [adjusted hazard ratio (HR): 0.67; 95% confidence interval (CI): 0.45–0.97; P = 0.04], independently of pre‐procedural NT‐proBNP levels and other clinical parameters. The percent change in NT‐proBNP was associated with a linear trend of the incidence of the composite outcome (adjusted HR per 10% decrease: 0.96; 95% CI: 0.94–0.98; P < 0.001). A stratified analysis revealed that the prognostic impact of the significant reduction in NT‐proBNP was consistent among clinical subgroups, including aetiology of mitral regurgitation (P for interaction = 0.99). Higher pre‐procedural NT‐proBNP level (>2485 pg/mL) was associated with the increased risk of the composite outcome (adjusted HR: 1.50; 95% CI: 1.03–2.17; P = 0.03); however, patients with a higher pre‐procedural NT‐proBNP who achieved the significant reduction in NT‐proBNP had a similar risk of the composite outcome to those with a lower pre‐procedural NT‐proBNP.

Conclusions

Changes in sequential NT‐proBNP measurements were associated with clinical outcomes within 2 years after TMVR. The assessment of NT‐proBNP dynamics may be valuable to assess the residual risk for patients undergoing TMVR and could assist with post‐procedural management after TMVR.

MitraClip and left ventricular reverse remodelling: a strain imaging study

AIMS

The purpose of this study is to identify echocardiography predictors of clinical response and reverse left ventricular (LV) remodelling in patients with functional mitral regurgitation (FMR) treated with MitraClip.

METHOD AND RESULTS

We retrospectively analysed 86 high surgical risk patients with severe FMR; of those, 58 were implanted a MitraClip, and 28 received medical treatment and served as controls. At baseline and at 1-year follow-up, we performed clinical and echocardiography evaluation to assess global longitudinal strain (GLS) and myocardial work [global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE)]. Mitral regurgitation was significantly reduced after MitraClip implantation (3.7 ± 0.4 vs. 1.7 ± 0.8, P < 0.001), and the procedure was associated with improvement in brain natriuretic peptide levels (980 ± 1027 vs. 420 ± 338 pg/mL, P < 0.001), New York Heart Association class status (3.2 ± 0.55 vs. 2.0 ± 0.6, P < 0.001), 6-min walking test (233 ± 154 vs. 286 ± 114 m, P = 0.01) at follow-up and reduction of left ventricle end-systolic (LVESV) and left ventricle end-diastolic volumes (LVEDV) (152 ± 68 vs. 136 ± 43 mL, P = 0.004 & 219 ± 74 vs. 193 ± 66 mL, P = 0.001, respectively). MitraClip procedure was associated with improvement of LV performance and significant increase of GWI (607 ± 282 vs. 650 ± 260 mmHg%, P = 0.045) and GCW (854 ± 288 vs. 949 ± 325 mmHg%, P < 0.001). Baseline ejection fraction (EF), GLS, GWI, GCW, and effective regurgitant orifice area were the variables that were associated with reduction of LVEDV 1 year after intervention (P < 0.05 for all) and baseline GCW of the LV was the only variable associated with reduction of LVESV (P = 0.002). Receiver operating characteristic curve analysis identified that a GLS cut-off value of -8.65% (AUC 0.815, P = 0.007) was associated with a 20% reduction of the LVEDV with a sensitivity and specificity of 72% and 70%, respectively, and that a GCW cut-off value of 846 mmHg% (AUC 0.759, P = 0.007) was associated with a 10% reduction of LVESV with sensitivity and specificity 79% and 74%, respectively.

CONCLUSIONS

Mitral valve repair with MitraClip has positive clinical and echocardiographic impact in patients with FMR 1 year after implantation. Preserved GLS and GCW values appear to be associated with LV reverse remodelling post intervention.

Functional Role of Natriuretic Peptides in Risk Assessment and Prognosis of Patients with Mitral Regurgitation

The management of mitral valve regurgitation (MR), a common valve disease, represents a challenge in clinical practice, since the indication for either surgical or percutaneous valve replacement or repair are guided by symptoms and by echocardiographic parameters which are not always feasible. In this complex scenario, the use of natriuretic peptide (NP) levels would serve as an additive diagnostic and prognostic tool. These biomarkers contribute to monitoring the progression of the valve disease, even before the development of hemodynamic consequences in a preclinical stage of myocardial damage. They may contribute to more accurate risk stratification by identifying patients who are more likely to experience death from cardiovascular causes, heart failure, and cardiac hospitalizations, thus requiring surgical management rather than a conservative approach. This article provides a comprehensive overview of the available evidence on the role of NPs in the management, risk evaluation, and prognostic assessment of patients with MR both before and after surgical or percutaneous valve repair. Despite largely positive evidence, a series of controversial findings exist on this relevant topic. Recent clinical trials failed to assess the role of NPs following the interventional procedure. Future larger studies are required to enable the introduction of NP levels into the guidelines for the management of MR.