Left Ventricular Global Longitudinal Strain as a Predictor of Outcomes in Patients with Heart Failure with Secondary Mitral Regurgitation: The COAPT Trial

Preprocedural transthoracic echocardiography for predicting outcomes of transcatheter edge-to-edge repair for chronic primary mitral regurgitation

INTRODUCTION AND OBJECTIVES

Limited data exist on the prognostic usefulness of transthoracic echocardiography preceding MitraClip for chronic primary mitral regurgitation (MR). We evaluated the predictive ability of transthoracic echocardiography in this setting.

METHODS

A total of 410 patients (median age, 83 years, 60.7% males) were included in the study. The primary outcome was the 1-year composite of all-cause mortality or heart failure hospitalization. Secondary endpoints encompassed individual elements of the primary outcome, the persistence of significant functional impairment or above-moderate MR at 1 year, and above-mild MR at 1-month.

RESULTS

The only parameter associated with the risk of the primary outcome was a ventricular end systolic diameter index of ≥2.1 cm/m2, corresponding to the cohort's 4th quartile (HR, 2.44; 95%CI, 1.09-4.68; P=.022). Concurrently, higher left atrial volume index (LAVi) and a mid-diastolic medial-lateral mitral annular diameter (MAD) equal to or above the cohort's median of 32.2mm were linked to a higher probability of death and heart failure hospitalization, respectively. LAVi of ≥ 60mL/m2, above-mild mitral annular calcification, and above-moderate tricuspid regurgitation conferred higher odds of functional class III-IV or above-moderate MR persistence. All variables except LAVi and MAD, as well as indexed mid-diastolic medial-lateral MAD of ≥ 20.2mm/m2 and mitral effective regurgitant orifice area of ≥ 0.40 cm2, were associated with greater-than-mild MR at 1 month.

CONCLUSIONS

Preprocedural increased indexed left heart dimensions, mainly left ventricular end-systolic diameter index, MAD, mitral annular calcification, mitral effective regurgitant orifice area, and tricuspid regurgitation mark a less favorable course post-MitraClip for chronic primary MR.

Prognostic value of left ventricular global longitudinal strain in transcatheter edge-to-edge repair for chronic primary mitral regurgitation

AIMS

Left ventricular global longitudinal strain (LVGLS) is a known outcome predictor in transcatheter edge-to-edge repair (TEER) for functional mitral regurgitation (MR). We aimed to assess its prognostic yield in the setting of TEER for chronic primary MR.

METHODS AND RESULTS

We conducted a single-centre, retrospective analysis of 323 consecutive patients undergoing isolated, first-time procedures. Stratified by baseline LVGLS quartiles (≤-19%, -18.9% to -16%, -15.9% to -12%, >-12%), the cohort was evaluated for the primary composite outcome of all-cause mortality or heart failure hospitalizations, as well as secondary endpoints consisting of mitral reinterventions and the persistence of significant residual MR and/or functional disability-all along the first year after intervention. Subjects with worse (i.e. less negative) LVGLS exhibited higher comorbidity, more advanced HF, and elevated procedural risk. Post-TEER, those belonging to the worst LVGLS quartile group sustained increased mortality (16.9% vs. 6.3%, Log-Rank P = 0.005, HR 1.75, 95% CI 1.08-4.74, P = 0.041) and, when affected by LV dysfunction/dilatation, more primary outcome events (21.1% vs. 11.5%, Log-Rank P = 0.037, HR 1.68, 95% CI 1.02-5.46, P = 0.047). No association was demonstrated between baseline LVGLS and other endpoints. Upon exploratory analysis, 1-month post-procedural LVGLS directly correlated with and was worse than its baseline counterpart by 1.6%, and a more impaired 1-month value-but not the presence/extent of deterioration-conferred heightened risk for the primary outcome.

CONCLUSION

TEER for chronic primary MR is feasible, safe, and efficacious irrespective of baseline LVGLS. Yet, worse baseline LVGLS forecasts a less favourable post-procedural course, presumably reflecting a higher-risk patient profile.

Left Atrial Improvement in Patients With Secondary Mitral Regurgitation and Heart Failure: The COAPT Trial

BACKGROUND

Functional mitral regurgitation induces adverse effects on the left ventricle and the left atrium. Left atrial (LA) dilatation and reduced LA strain are associated with poor outcomes in heart failure (HF). Transcatheter edge-to-edge repair (TEER) of the mitral valve reduces heart failure hospitalization (HFH) and all-cause death in selected HF patients.

OBJECTIVES

The aim of this study was to evaluate the impact of LA strain improvement 6 months after TEER on the outcomes of patients enrolled in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial.

METHODS

The difference in LA strain between baseline and the 6-month follow-up was calculated. Patients with at least a 15% improvement in LA strain were labeled as "LA strain improvers." All-cause death and HFH were assessed between the 6 and 24-month follow-up.

RESULTS

Among 347 patients (mean age 71 ± 12 years, 63% male), 106 (30.5%) showed improvement of LA strain at the 6-month follow-up (64 [60.4%] from the TEER + guideline-directed medical therapy [GDMT] group and 42 [39.6%] from the GDMT alone group). An improvement in LA strain was significantly associated with a reduction in the composite of death or HFH between the 6-month and 24-month follow-up, with a similar risk reduction in both treatment arms (Pinteraction = 0.27). In multivariable analyses, LA strain improvement remained independently associated with a lower risk of the primary composite endpoint both as a continuous variable (adjusted HR: 0.94 [95% CI: 0.89-1.00]; P = 0.03) and as a dichotomous variable (adjusted HR: 0.49 [95% CI: 0.27-0.89]; P = 0.02). The best outcomes were observed in patients treated with TEER in whom LA strain improved.

CONCLUSIONS

In symptomatic HF patients with severe mitral regurgitation, improved LA strain at the 6-month follow-up is associated with subsequently lower rates of the composite endpoint of all-cause mortality or HFH, both after TEER and GDMT alone. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [COAPT]; NCT01626079).

Moving from left ventricular ejection fraction to deformation imaging in mitral valve regurgitation

The increasing prevalence of valvular heart diseases, specifically mitral regurgitation (MR), underscores the need for a careful and timely approach to intervention. Severe MR, whether primary or secondary, when left untreated leads to adverse outcomes, emphasizing the critical role of a timely surgical or transcatheter intervention. While left ventricular ejection fraction (LVEF) remains the guideline-recommended measure for assessing left ventricle damage, emerging evidence raises concerns regarding its reliability in MR due to its volume-dependent nature. This review summarizes the existing literature on the role of LVEF and deformation imaging techniques, emphasizing the latter's potential in providing a more accurate evaluation of intrinsic myocardial function. Moreover, it advocates the need for an integrated approach that combines traditional with emerging measures, aiming to optimize the management of patients with MR. It attempts to highlight the need for future research to validate the clinical application of deformation imaging techniques through large-scale studies.

Efficacy of Native T1 Mapping for Patients With Non-Ischemic Cardiomyopathy and Ventricular Functional Mitral Regurgitation Undergoing Transcatheter Edge-to-Edge Repair

BACKGROUND

We investigated the efficacy of left ventricular (LV) myocardial damage by native T1mapping obtained with cardiac magnetic resonance (CMR) for patients undergoing transcatheter edge-to-edge repair (TEER).Methods and Results: We studied 40 symptomatic non-ischemic heart failure (HF) patients and ventricular functional mitral regurgitation (VFMR) undergoing TEER. LV myocardial damage was defined as the native T1Z-score, which was converted from native T1values obtained with CMR. The primary endpoint was defined as HF rehospitalization or cardiovascular death over 12 months after TEER. Multivariable Cox proportional hazards analysis showed that the native T1Z-score was the only independent parameter associated with cardiovascular events (hazard ratio 3.40; 95% confidential interval 1.51-7.67), and that patients with native T1Z-scores <2.41 experienced significantly fewer cardiovascular events than those with native T1Z-scores ≥2.41 (P=0.001). Moreover, the combination of a native T1Z-score <2.41 and more severe VFMR (effective regurgitant orifice area [EROA] ≥0.30 cm2) was associated with fewer cardiovascular events than a native T1Z-score ≥2.41 and less severe VFMR (EROA <0.30 cm2; P=0.002).

CONCLUSIONS

Assessment of baseline LV myocardial damage based on native T1Z-scores obtained with CMR without gadolinium-based contrast media is a valuable additional parameter for better management of HF patients and VFMR following TEER.

Patient-Specific Quantitative In-Vivo Assessment of Human Mitral Valve Leaflet Strain Before and After MitraClip Repair

PURPOSE

Mitral regurgitation (MR) is a highly prevalent and deadly cardiac disease characterized by improper mitral valve (MV) leaflet coaptation. Among the plethora of available treatment strategies, the MitraClip is an especially safe option, but optimizing its long-term efficacy remains an urgent challenge.

METHODS

We applied our noninvasive image-based strain computation pipeline [1] to intraoperative transesophageal echocardiography datasets taken from ten patients undergoing MitraClip repair, spanning a range of MR etiologies and MitraClip configurations. We then analyzed MV leaflet strains before and after MitraClip implementation to develop a better understanding of (1) the pre-operative state of human regurgitant MV, and (2) the MitraClip's impact on the MV leaflet deformations.

RESULTS

The MV pre-operative strain fields were highly variable, underscoring both the heterogeneity of the MR in the patient population and the need for patient-specific treatment approaches. Similarly, there were no consistent overall post-operative strain patterns, although the average A2 segment radial strain difference between pre- and post-operative states was consistently positive. In contrast, the post-operative strain fields were better correlated to their respective pre-operative strain fields than to the inter-patient post-operative strain fields. This quantitative result implies that the patient specific pre-operative state of the MV guides its post-operative deformation, which suggests that the post-operative state can be predicted using pre-operative data-derived modelling alone.

CONCLUSIONS

The pre-operative MV leaflet strain patterns varied considerably across the range of MR disease states and after MitraClip repair. Despite large inter-patient heterogeneity, the post-operative deformation appears principally dictated by the pre-operative deformation state. This novel finding suggests that though the variation in MR functional state and MitraClip-induced deformation were substantial, the post-operative state can be predicted from the pre-operative data alone. This study suggests that, with use of larger patient cohort and corresponding long-term outcomes, quantitative predictive factors of MitraClip durability can be identified.

Changes in Left Ventricular Global Longitudinal Strain in Patients With Heart Failure and Secondary Mitral Regurgitation: The COAPT Trial

Background Left ventricular (LV) global longitudinal strain (GLS) provides incremental prognostic information over LV ejection fraction in patients with heart failure (HF) and secondary mitral regurgitation. We examined the prognostic impact of LV GLS improvement in this population. Methods and Results The COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial randomized symptomatic patients with HF with severe (3+/4+) mitral regurgitation to transcatheter edge-to-edge repair with the MitraClip device plus maximally tolerated guideline-directed medical therapy (GDMT) versus GDMT alone. LV GLS was measured at baseline and 6-month follow-up. The relationship between the improvement in LV GLS from baseline to 6 months and the composite of all-cause death or HF hospitalization between 6- and 24-month follow-up were assessed. Among 383 patients, 174 (45.4%) had improved LV GLS at 6-month follow-up (83/195 [42.6%] with transcatheter edge-to-edge repair+GDMT and 91/188 [48.4%] with GDMT alone; P=0.25). Improvement in LV GLS was strongly associated with reduced death or HF hospitalization between 6 and 24 months (P<0.009), with similar risk reduction in both treatment arms (Pinteraction=0.40). By multivariable analysis, LV GLS improvement at 6 months was independently associated with a lower risk of death or HF hospitalization (hazard ratio [HR], 0.55 [95% CI, 0.36-0.83]; P=0.009), death (HR, 0.48 [95% CI, 0.29-0.81]; P=0.006), and HF hospitalization (HR, 0.50 [95% CI, 0.31-0.81]; P=0.005) between 6 and 24 months. Conclusions Among patients with HF and severe mitral regurgitation in the COAPT trial, improvement in LV GLS at 6-month follow-up was associated with improved outcomes after both transcatheter edge-to-edge repair and GDMT alone between 6 and 24 months. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01626079.

Prognostic Relevance of Left Ventricular Global Longitudinal Strain in Patients With Heart Failure and Reduced Ejection Fraction

Patients with heart failure (HF) and reduced ejection fraction (HFrEF) are complex patients who often have a high prevalence of co-morbidities and risk factors. In the present study, we investigated the prognostic significance of left ventricular (LV) global longitudinal strain (GLS) along with important clinical and echocardiographic variables in patients with HFrEF. Patients who had a first echocardiographic diagnosis of LV systolic dysfunction, defined as LV ejection fraction ≤45%, were selected. The study population was subdivided into 2 groups based on a spline curve analysis derived optimal threshold value of LV GLS (≤10%). The primary end point was occurrence of worsening HF, whereas the composite of worsening HF and all-cause death was chosen for the secondary end point. A total of 1,873 patients (mean age 63 ± 12 years, 75% men) were analyzed. During a median follow-up of 60 months (interquartile range 27 to 60 months), 256 patients (14%) experienced worsening HF and the composite end point of worsening HF and all-cause mortality occurred in 573 patients (31%). The 5-year event-free survival rates for the primary and secondary end point were significantly lower in the LV GLS ≤10% group compared with the LV GLS >10% group. After adjustment for important clinical and echocardiographic variables, baseline LV GLS remained independently associated with a higher risk of worsening HF (hazard ratio 0.95, 95% confidence interval 0.90 to 0.99, p = 0.032) and the composite of worsening HF and all-cause mortality (hazard ratio 0.94, 95% confidence interval 0.90 to 0.97, p = 0.001). In conclusion, baseline LV GLS is associated with long-term prognosis in patients with HFrEF, independent of various clinical and echocardiographic predictors.

Prognostic Stratification of Clinically Stable Patients with Heart Failure by Echocardiographic Pressure/Volume Loop Model

BACKGROUND

Pressure/volume (P/V) loops provide useful information on left ventricular performance and prognosis in patients with heart failure (HF) but do not lend themselves to routine clinical practice. The authors developed a noninvasive method to compute individualized P/V loops to predict adverse clinical outcomes in patients with stable HF, which the authors believe can be used clinically.

METHODS

A derivation cohort (n = 443 patients) was used to develop an echocardiography P/V loop model, using brachial arterial pressure and trans-thoracic two-dimensional Doppler echocardiographic data. Each patient's P/V loop was depicted as an irregular pentagon, and a centroid was derived for each loop. The centroid distance (CD) from a reference centroid (derived from 101 healthy control subjects) was computed. This model was prospectively applied to 435 patients who constituted the validation cohort. The study end point was a composite of cardiac death or hospitalization for HF among study patients.

RESULTS

In the derivation cohort, CD was threefold greater among patients who experienced adverse events than those who did not. During a follow-up period of 30 months (15-45 months), event rates were 35% (72 of 206 patients) and 12% (29 of 237 patients P < .001), respectively, among patients with CD > 33 mL/mm Hg and those with CD ≤33 mL/mm Hg (prognostic cutoff derived by receiver operating characteristic analysis). Multivariate Cox analysis identified CD as an independent predictor of adverse outcome (hazard ratio, 1.61; 95% CI, 1.03-2.50) independently of left ventricular end-diastolic volume, pulmonary capillary wedge pressure, and left ventricular ejection fraction. These conclusions were confirmed in the validation cohort.

CONCLUSIONS

The authors propose a method to create a noninvasive P/V loop and its centroid. These data provide useful pathophysiologic and prognostic information in patients with HF.

Ventricular Remodeling and Outcomes After Mitral Transcatheter Edge-to-Edge Repair in Heart Failure: The COAPT Trial

BACKGROUND

The relationship between left ventricular (LV) remodeling and clinical outcomes after treatment of severe mitral regurgitation (MR) in heart failure (HF) has not been examined.

OBJECTIVES

The aim of this study was to evaluate the association between LV reverse remodeling and subsequent outcomes and assess whether transcatheter edge-to-edge repair (TEER) and residual MR are associated with LV remodeling in the COAPT (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation) trial.

METHODS

Patients with HF and severe MR who remained symptomatic on guideline-directed medical therapy (GDMT) were randomized to TEER plus GDMT or GDMT alone. Baseline and 6-month core laboratory measurements of LV end-diastolic volume index and LV end-systolic volume index were examined. Change in LV volumes from baseline to 6 months and clinical outcomes from 6 months to 2 years were evaluated using multivariable regression.

RESULTS

The analytical cohort comprised 348 patients (190 treated with TEER, 158 treated with GDMT alone). A decrease in LV end-diastolic volume index at 6 months was associated with reduced cardiovascular death between 6 months and 2 years (adjusted HR: 0.90 per 10 mL/m² decrease; 95% CI: 0.81-1.00; P = 0.04), with consistent results in both treatment groups (P_interaction = 0.26). Directionally similar but nonsignificant relationships were present for all-cause death and HF hospitalization and between reduced LV end-systolic volume index and all outcomes. Neither treatment group nor MR severity at 30 days was associated with LV remodeling at 6 or 12 months. The treatment benefits of TEER were not significant regardless of the degree of LV remodeling at 6 months.

CONCLUSIONS

In patients with HF and severe MR, LV reverse remodeling at 6 months was associated with subsequently improved 2-year outcomes but was not affected by TEER or the extent of residual MR. (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation [The COAPT Trial] and COAPT CAS [COAPT]; NCT01626079).

Prognostic value of left ventricular global longitudinal strain in mitral regurgitation: a systematic review

Conventional echocardiographic assessment may overestimate the left ventricular (LV) function in mitral regurgitation (MR). LV global longitudinal strain (GLS) is more sensitive marker to detect subclinical LV dysfunction. Multiple studies have investigated the prognostic value of LV-GLS in MR to examine its potential to determine the timing and indication of intervention. This systematic review aimed to assess the prognostic value of LV-GLS in patients with mitral regurgitation (MR) to define its clinical applicability. PUBMED and EMBASE were queried through July 2021 to identify studies investigating the prognostic value of LV-GLS in MR. A total of 24 observational studies with 5267 patients were identified. Sixteen studies investigated for primary MR, 7 studies for secondary MR, and 1 study for both. Most studies included patients who underwent intervention. There was significant heterogeneity in patient population, intervention status, follow-up period, LV-GLS cutoff value, outcomes, and statistical methods among the studies. Meta-analysis was not performed considering the significant variability. With exception to 1 study, all studies demonstrated significant association between impaired LV-GLS and worse clinical and echocardiographic outcomes in primary MR. Prognostic value of LV-GLS in secondary MR was less certain due to inconsistent findings and limited reporting. LV-GLS is a promising parameter of prognostication in primary MR and can be considered as alternative to determine the timing of intervention. However, the optimal cutoff value remains unclear. The prognostic value of LV-GLS in secondary MR is less clear. Further large-scale prospective study is warranted before its routine clinical application.

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.