Duration of reverse remodeling response to cardiac resynchronization therapy: Rates, predictors, and clinical outcomes

Mechanisms of myocardial reverse remodelling and its clinical significance: A scientific statement of the ESC Working Group on Myocardial Function

Cardiovascular disease (CVD) is the leading cause of morbimortality in Europe and worldwide. CVD imposes a heterogeneous spectrum of cardiac remodelling, depending on the insult nature, that is, pressure or volume overload, ischaemia, arrhythmias, infection, pathogenic gene variant, or cardiotoxicity. Moreover, the progression of CVD-induced remodelling is influenced by sex, age, genetic background and comorbidities, impacting patients' outcomes and prognosis. Cardiac reverse remodelling (RR) is defined as any normative improvement in cardiac geometry and function, driven by therapeutic interventions and rarely occurring spontaneously. While RR is the outcome desired for most CVD treatments, they often only slow/halt its progression or modify risk factors, calling for novel and more timely RR approaches. Interventions triggering RR depend on the myocardial insult and include drugs (renin-angiotensin-aldosterone system inhibitors, beta-blockers, diuretics and sodium-glucose cotransporter 2 inhibitors), devices (cardiac resynchronization therapy, ventricular assist devices), surgeries (valve replacement, coronary artery bypass graft), or physiological responses (deconditioning, postpartum). Subsequently, cardiac RR is inferred from the degree of normalization of left ventricular mass, ejection fraction and end-diastolic/end-systolic volumes, whose extent often correlates with patients' prognosis. However, strategies aimed at achieving sustained cardiac improvement, predictive models assessing the extent of RR, or even clinical endpoints that allow for distinguishing complete from incomplete RR or adverse remodelling objectively, remain limited and controversial. This scientific statement aims to define RR, clarify its underlying (patho)physiologic mechanisms and address (non)pharmacological options and promising strategies to promote RR, focusing on the left heart. We highlight the predictors of the extent of RR and review the prognostic significance/impact of incomplete RR/adverse remodelling. Lastly, we present an overview of RR animal models and potential future strategies under pre-clinical evaluation.

A review of biomarker and imaging monitoring to predict heart failure recovery

Heart failure is a clinical syndrome caused by structural cardiac abnormalities that lead to increased intracardiac pressures and decreased cardiac output. Following cardiovascular insult or direct myocardial injury, neurohormonal activation triggers hemodynamic changes and cardiac remodeling to preserve cardiac output. While initially adaptive, cardiac remodeling eventually causes pathologic changes in cardiac structure that often compromise cardiac function. Reverse remodeling is the regression of abnormal cardiac chamber geometry and function after myocardial injury. In recent years, several classes of therapeutics have been associated with greater likelihood of reverse remodeling. Heart failure recovery and heart failure remission, terms encompassing the clinical correlates of reverse remodeling, have been associated with improved survival in patients with heart failure with reduced ejection. As such, identifying predictors of heart failure recovery can have important implications for guiding clinical practice and therapeutic innovation. This review addresses the role of biomarkers and imaging monitoring in predicting structural, functional, and clinical recovery in patients with acute and chronic heart failure.

What Have We Learned in the Last 20 Years About CRT Non-Responders?

Although cardiac resynchronization therapy (CRT) has become well established in the treatment of heart failure, the management of patients who do not respond after CRT remains a key challenge. This review will summarize what we have learned about non-responders over the last 20 years and discuss methods for optimizing response, including the introduction of novel therapies.

Long-term outcomes of left bundle branch area pacing versus biventricular pacing in patients with heart failure and complete left bundle branch block

Left bundle branch area pacing (LBBAP) has developed in an effort to improve cardiac resynchronization therapy (CRT). We aimed to compare the long-term clinical outcomes between LBBAP and biventricular pacing (BIVP) in patients with heart failure (HF) and complete left bundle branch block (CLBBB). Consecutive patients with HF and CLBBB requiring CRT received either LBBAP or BIVP were recruited at the Second Affiliated Hospital of Nanchang University from February 2018 to May 2019. We assessed their implant parameters, electrocardiogram (ECG), clinical outcomes at implant and during follow-up at 1, 3, 6, 12, and 24 months. Forty-one patients recruited including 21 for LBBAP and 20 for BIVP. Mean follow-up duration was 23.71 ± 4.44 months. LBBAP produced lower pacing thresholds, shorter procedure time and fluoroscopy duration compared to BIVP. The QRS duration was significantly narrower after LBBAP than BIVP (129.29 ± 31.46 vs. 156.85 ± 26.37 ms, p = 0.005). Notably, both LBBAP and BIVP significantly improved LVEF, LVEDD, NYHA class, and BNP compared with baseline. However, LBBAP significantly lowered BNP compared with BIVP (416.69 ± 411.39 vs. 96.07 ± 788.71 pg/ml, p = 0.007) from baseline to 24-month follow-up. Moreover, patients who received LBBAP exhibited lower number of hospitalizations than those in the BIVP group (p = 0.019). In addition, we found that patients with moderately prolonged left ventricular activation time (LVAT) and QRS notching in limb leads in baseline ECG respond better to LBBAP for CLBBB correction. LBBAP might be a relative safe and effective resynchronization therapy and as a supplement to BIVP for patients with HF and CLBBB.

Re-worsening left ventricular ejection fraction after response to cardiac resynchronization therapy

BACKGROUND

Although cardiac resynchronization therapy (CRT) provided functional and clinical improvement in patients with heart failure (HF) and electrical intraventricular conduction disturbances, some patients had re-worsening left ventricular (LV) function after a favorable CRT response. We analyzed the clinical variables and cardiac outcomes associated with this re-worsening LV function after CRT.

METHODS

In this study, 71 patients with CRT response who received CRT between 2006 and 2017 were included. CRT response was defined as a "≥ 10% improvement in LV ejection fraction (LVEF) on follow-up." Patients were classified into two groups: (i) persistent: (n = 48, 68%), defined as those with a CRT response and (ii) re-worsening: (n = 23, 32%), consisting of those who fell out of the definition of a CRT response after an initial CRT response.

RESULTS

Half of the patients in the re-worsening group failed to maintain a CRT response from two years upwards. A longer duration from HF diagnosis to CRT implantation, nonspecific intraventricular conduction delay (NIVCD) on electrocardiogram at CRT implantation, and a lower increased LVEF at initial CRT response were independent predictors for the re-worsening group. Patients in the re-worsening group had a higher incidence rate for HF hospitalization and cardiac deaths, compared with those in the persistent group.

CONCLUSION

One-third of CRT responders experienced re-worsening LVEF, which was associated with poor outcomes. CRT responders with NIVCD, longer HF duration, and a lower increased LVEF at initial CRT response should be monitored with caution.

Distinctively different predictors for long-term outcomes between responders and nonresponders who underwent cardiac resynchronization therapy

BACKGROUND

It is common to develop heart failure (HF) events even in respondents to cardiac resynchronization therapy (CRT) during a long-term observation period. We investigated the predictors for long-term outcome in responders in comparison with nonresponders in patients diagnosed with HF along with implanted CRT.

METHODS

We enrolled 133 consecutive patients (mean age, 70 ± 10 years; 72 males) implanted with CRT from April 2010 to July 2019. Accurate follow-up information (mean follow-up period, 983 ± 801 days) was obtained from 66 responders and 53 nonresponders.

RESULTS

Kaplan-Meier event-free curves showed that major adverse cerebral and cardiovascular event (MACCE)-free ratio was significantly lower as the stage of renal function progresses (log rank, 19.5; P < .0001). The baseline estimated glomerular filtration rate (e-GFR) before CRT was not significantly different between nonresponders and responders. The e-GFR after judgment of CRT response was lower in patients with MACCEs than those without. Cox proportional hazards regression analysis revealed that low baseline e-GFR before CRT and after judgment of CRT response was closely related with MACCEs in responders, but not in nonresponders. The survival rate in responders without MACCEs assessed using Kaplan-Meier analysis was significantly larger in the preserved e-GFR (baseline value before CRT, >44 mL/min/1.73 m2) group than in the depressed group (log rank, 20.29; P < .0001).

CONCLUSION

We demonstrate that the factors for MACCEs during long follow-up periods were distinctively different between responders and nonresponders. Patients with depressed e-GFRs are suggested to have poor prognosis even if they are responders to CRT.

Risk of ventricular arrhythmia in cardiac resynchronization therapy responders and super-responders: a systematic review and meta-analysis

AIMS

Response to cardiac resynchronization therapy (CRT) is associated with improved survival, and reduction in heart failure hospitalization, and ventricular arrhythmia (VA) risk. However, the impact of CRT super-response [CRT-SR, increase in left ventricular ejection fraction (LVEF) to ≥ 50%] on VA remains unclear.

METHODS AND RESULTS

We undertook a meta-analysis aimed at determining the impact of CRT response and CRT-SR on risk of VA and all-cause mortality. Systematic search of PubMed, EMBASE, and Cochrane databases, identifying all relevant English articles published until 31 December 2019. A total of 34 studies (7605 patients for VA and 5874 patients for all-cause mortality) were retained for the meta-analysis. The pooled cumulative incidence of appropriate implantable cardioverter-defibrillator therapy for VA was significantly lower at 13.0% (4.5% per annum) in CRT-responders, vs. 29.0% (annualized rate of 10.0%) in CRT non-responders, relative risk (RR) 0.47 [95% confidence interval (CI) 0.39-0.56, P < 0.0001]; all-cause mortality 3.5% vs. 9.1% per annum, RR of 0.38 (95% CI 0.30-0.49, P < 0.0001). The pooled incidence of VA was significantly lower in CRT-SR compared with CRT non-super-responders (non-responders + responders) at 0.9% vs. 3.8% per annum, respectively, RR 0.22 (95% CI 0.12-0.40, P < 0.0001); as well as all-cause mortality at 2.0% vs. 4.3%, respectively, RR 0.47 (95% CI 0.33-0.66, P < 0.0001).

CONCLUSIONS

Cardiac resynchronization therapy super-responders have low absolute risk of VA and all-cause mortality. However, there remains a non-trivial residual absolute risk of these adverse outcomes in CRT responders. These findings suggest that among CRT responders, there may be a continued clinical benefit of defibrillators.

Clinical significance of left atrial geometry in dilated cardiomyopathy patients: A cardiovascular magnetic resonance study

Background

Clinical significance of left atrial (LA) function and geometry in patients with dilated cardiomyopathy (DCM) remains uncertain.

Hypothesis

LA geometric parameters assessed by cardiac magnetic resonance (CMR) predict the prognosis in patients with DCM.

Methods

The present study included patients with DCM and sinus rhythm who underwent CMR between December 2007 and April 2018. LA volume was measured using CMR. LA sphericity index was computed as the ratio of the measured maximum LA volume by the volume of a sphere with maximum LA length diameter.

Results

We included 255 patients in this study. During the mean follow‐up of 3.92 years, hospitalization for HF occurred in 37 patients. The LA sphericity index was significantly higher in patients with hospitalization for HF than in those without (0.78 ± 0.35 vs. 0.58 ± 0.18, p < .001). Multivariable Cox regression analysis identified a higher LA sphericity index as an independent predictor of hospitalization for HF. Patients were categorized based on the median of LA sphericity index. The Kaplan–Meier curve showed that patients with a high LA sphericity index (≥0.57) had a significantly higher risk of hospitalization for HF than those with a low LA sphericity index (<0.57).

Conclusion

LA sphericity index was an independent predictor of hospitalization for HF. Assessment of LA geometric parameters might be useful for risk stratification in patients with DCM.

Effect of Diabetes Mellitus on Cardiac Resynchronization Therapy and to Prognosis in Heart Failure (from the Prospective Evaluation of Asian With Cardiac Resynchronization Therapy for Heart Failure Study)

The association of diabetes mellitus (DM) with cardiac resynchronization therapy (CRT) response and cardiovascular outcomes in Asian patients with heart failure (HF) is unclear. This study aims to investigate the effects of DM on CRT response and cardiovascular outcomes in Asian HF patients. Consecutive Asian HF patients receiving CRT were enrolled in the Prospective Evaluation of Asian with CRT for Heart Failure (PEACH) study from 2011 to 2017. CRT response and super-response were defined as decrease in end-systolic volume index ≥15% and ≥30%, respectively. Primary endpoint was time to composite of HF-hospitalization and all-cause mortality. Among 161 patients followed for 3.3 ± 1.5 years (age 66.7 ± 11.2 years, 22% females, mean QRS duration 154.3 ± 22.4 ms, 83% left bundle branch block), 84 (52%) were CRT responders and 57 (35%) were super-responders. Of 82 (51%) patients with DM (100% type 2, mean HbA1c 7.3 ± 1.9%), 35 (43%) were responders. DM attenuated reverse remodeling (CRT response: AOR 0.44, 95% confidence interval [CI] 0.20 to 0.98, p < 0.05; super-response: AOR 0.42, 95% CI 0.18 to 0.97, p <0.05), and DM increased HF-hospitalization and all-cause mortality (AHR 1.68, 95% CI 1.00 to 2.82, p = 0.05). The extent of CRT-response correlates with higher event-free survival (CRT response: AHR 0.5, 95% CI 0.30 to 0.81, p = 0.005; super-response: AHR 0.27, 95% CI 0.14 to 0.52, p < 0.001). In conclusion, the extent of reverse remodeling post-CRT is the strongest predictor of event free survival. However, DM is detrimental to the CRT recipient by attenuating reverse remodeling, inducing end organ dysfunction and is independently associated with worsened clinical outcomes among Asian HF patients.

Left ventricular reverse remodelling predicts long-term outcomes in patients with functional mitral regurgitation undergoing MitraClip therapy: results from a multicentre registry

AIMS

To explore whether left ventricular reverse remodelling (LVRR) is a predictor of outcomes in patients with functional mitral regurgitation (FMR) undergoing MitraClip procedure.

METHODS AND RESULTS

We analysed 184 consecutive patients with FMR who underwent successful MitraClip procedure. LVRR was defined as a reduction in left ventricular end-systolic volume ≥ 10% from baseline to 6 months. LVRR was observed in 79 (42.9%) patients. Compared with non-LVRR, LVRR patients were more likely to be females, less likely to have an ischaemic aetiology of mitral regurgitation or a prior (<6 months) heart failure (HF) hospitalization, and had smaller left ventricular dimensions. New York Heart Association class improved from baseline up to 1-year follow-up in both groups. Higher rates of overall survival (87.3% vs. 75.2%, P = 0.039), freedom from HF hospitalization (77.2% vs. 60%, P = 0.020), and freedom from the composite endpoint (cardiovascular mortality or HF hospitalization) (74.7% vs. 55.2%; P = 0.012) were observed in LVRR vs. non-LVRR patients at 2-year follow-up. LVRR was associated with a significant reduction of the adjusted relative risk of mortality, HF hospitalization and composite endpoint [hazard ratio (HR) 0.44; 95% confidence interval (CI) 0.20-0.96, P = 0.040; HR 0.55; 95% CI 0.32-0.97, P = 0.038; and HR 0.54; 95% CI 0.32-0.92, P = 0.023, respectively]. Female gender, absence of diabetes, freedom from prior HF hospitalization, non-ischaemic aetiology of mitral regurgitation, and left ventricular end-diastolic diameter < 75 mm were found to be independent predictors of LVRR.

CONCLUSIONS

Left ventricular reverse remodelling is associated with better long-term outcomes in patients with FMR successfully treated with MitraClip. A careful patient selection may be useful as specific baseline features predict favourable left ventricular remodelling. [Correction added on 17 January 2019, after online publication: the preceding sentence has been changed.].

Assessment of coronary flow reserve predicts long-term outcome of responders to cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) has been established as a treatment for patients with chronic heart failure (HF). We tested the hypothesis that assessment of coronary flow reserve (CFR) predicts the long-term outcome of CRT. The study consisted of 114 HF patients implanted with a CRT device for the treatment of advanced HF between April 2010 and April 2018. After excluding patients that withdrew from long-term follow-up and patients missing a baseline CFR measurement, we enrolled 53 eligible patients. CFR was determined non-invasively by transthoracic echocardiography. Based on the ROC curve for predicting the appearance of major adverse cerebral and cardiovascular events (MACCE), the level of preserved CFR was set at >1.35 in responders. Accurate follow-up information (mean 873 ± 498 days) was obtained in 23 patients with a preserved CFR (16 females; mean age 71 ± 7.9 years) and 11 patients with a depressed CFR (5 females; mean age, 73 ± 7.6 years) in responders. Kaplan-Meier survival analysis demonstrated that the depressed CFR group had a higher prevalence of MACCE than the preserved CFR group (log rank, 9.83; p = 0.0021). Multivariate analysis revealed that depressed CFR was associated with MACCE (hazard ratio 4.88, 95% confidence interval 1.13-26.5, p = 0.0329). Our results suggest that the assessment of CFR predicts the outcome in responders to CRT. Preservation of coronary circulation flow might underlie one of the mechanisms for a better response to CRT in responders.