Effect of cardiac resynchronization therapy on mitral valve geometry: a novel aspect as "reversed mitral remodeling"

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.

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.

The role of three dimensional transesophageal echocardiography in predicting the effect of cardiac resynchronization therapy on mitral regurgitation in patients with low ejection fraction heart failure

PURPOSE

Cardiac resynchronization therapy (CRT) positively affects the improvement of functional mitral regurgitation (MR) in patients with heart failure with reduced ejection fraction (HFrEF). However, geometric changes in the mitral valve apparatus, subvalvular structures and their contribution to improving mitral regurgitation after CRT have not been clearly defined. Our study aimed to evaluate the geometric parameters of mitral valve apparatus measured with three-dimensional (3D) transesophageal echocardiography (TEE) before CRT implantation and to determine the parameters predicting the improvement of MR after CRT.

METHODS

In this prospective study, we included thirty patients with moderate or severe MR and HFrEF planned for CRT implantation who had an indication for TEE. Before CRT implantation, effective regurgitant orifice (ERO) and regurgitant volume (RV) measurements were performed. Detailed quantitative measurements of the mitral valve were done from recorded images by 3D TEE. ERO and RV measurements were repeated to evaluate MR at the end of the third month.

RESULTS

There were no significant changes in left ventricular EF and left ventricular diameters at third-month follow-up, whereas ERO and RV values were decreased. The posterior leaflet angle was higher in the non-responder group than the responder group (28.93 ± 8.41 vs 41.25 ± 10.90, p = 0.006). The posterior leaflet angle was an independent predictor of decreased RV and ERO.

CONCLUSION

Among HFrEF patients with moderate or severe functional MR who underwent CRT implantation had a lower posterior leaflet angle, which was measured by 3D TEE, in the patient group whose MR improved after CRT.

Relationship of Mechanical Dyssynchrony and LV Remodeling With Improvement of Mitral Regurgitation After CRT

OBJECTIVES

The aim of this study was to explore the association between mechanical dyssynchrony of the left ventricle before cardiac resynchronization therapy (CRT) and improvement of mitral regurgitation (MR) after CRT.

BACKGROUND

MR is very frequent among patients with dilated cardiomyopathy and conduction delay.

METHODS

Echocardiograms (pre-CRT and 12 ± 3.8 months thereafter) of 314 patients with dilated cardiomyopathy and any degree of MR, who underwent CRT device implantation according to guidelines, were analyzed. Left ventricular (LV) mechanical dyssynchrony was assessed by apical rocking (ApRock) and septal flash (SF), while MR severity was graded from I to IV on the basis of vena contracta width, regurgitation jet size, and proximal isovelocity surface area.

RESULTS

At baseline, 30% of patients presented with severe MR (grade III or IV). In 62% of patients, MR decreased after CRT, and these patients more frequently had left bundle branch block, had more severe MR, had more dilated left ventricles, had lower ejection fractions, and more often had ApRock and SF. Reverse remodeling was more frequent among patients with MR reduction (ΔLV end-systolic volume -35.5% ± 27.2% vs -4.1% ± 33.2%; P < 0.001). In a multivariable logistic stepwise regression, only ApRock (odds ratio [OR]: 3.8; 95% CI: 1.7-8.5; P = 0.001), SF (OR: 3.6; 95% CI: 1.6-7.9; P = 0.002), and baseline MR (OR: 1.4; 95% CI: 1.0-1.9; P = 0.046) remained significantly associated with MR reduction.

CONCLUSIONS

ApRock, SF, and severity of MR at baseline are strongly associated with MR reduction after CRT, while LV reverse remodeling is its underlying mechanism. Therefore, in patients with heart failure with LV dyssynchrony on optimal medical treatment, CRT should be the primary treatment attempt for relevant MR.

Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

Functional mitral regurgitation and cardiac resynchronization therapy in the "era" of trans-catheter interventions: Is it time to move from a staged strategy to a tailored therapy?

Cardiac resynchronization therapy (CRT) has been associated to left ventricle (LV) remodelling, reduction of functional mitral regurgitation (FMR) and clinical improvement in patients with heart failure and reduced ejection fraction (HFrEF). The prevalence of significant FMR in patients with LV dyssynchrony that are candidate to CRT is up to 40%. Current approach in patients with FMR undergoing CRT consists of re-evaluation of the amount of FMR following a waiting period of at least 3 months after the implant. In case of persistent significant FMR despite CRT and guideline directed medical therapy, trancatheter Mitral Valve repair (TMVR) is an important option to improve quality of life and prognosis. This stepwise approach does not take into account the probability of the individual response to CRT and the availability of TMVR solutions that are safe and effective in high risk patients. We reviewed the effects of CRT on FMR, the prognostic role of persistence of FMR after CRT treatment and the impact of treatment of FMR in patients CRT non responders. We aimed to point out the limits of current step-wised approach in light on more recent evidence regarding FMR treatment. A new, "tailored" approached is proposed.