Risk stratification in Arrhythmogenic Right Ventricular Cardiomyopathy: the impact of genotype on the 2019 ARVC risk calculator

Introduction

Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) is associated with sudden cardiac death (SCD). The 2019 ARVC risk model has been proposed as a method to quantify arrhythmic risk, but the impact of genotype its performance has not been addressed.

Purpose

To study arrhythmic outcomes in patients with ARVC and the performance of the 2019 ARVC risk model in predefined genetic subgroups.

Methods

This is an international, retrospective observational cohort study on consecutively evaluated patients with ARVC recruited from 17 centres in 7 countries. Inclusion criteria were: (i) a definite diagnosis of ARVC according to the 2010 Task Force Criteria; (ii) no history of sustained ventricular arrhythmia (VA) prior to first assessment at the participating centre; (iii) a follow up period of ≥1 month; (iv) age of diagnosis ≥14 years. Sustained ventricular arrhythmia (sustained ventricular tachycardia, appropriate implantable cardioverter defibrillator intervention, aborted SCD, or SCD) comprised the primary outcome (VA). Discriminative ability was assessed by Uno's concordance index (c-statistic) and calibration with the calibration plot slope. Fine-Gray regression was used to model the impact of clinical predictors on the arrhythmic outcome, in the context of competing risks (heart transplantation and non-arrhythmic death). The cumulative probability and 95% confidence intervals (95% CI) for the occurrence of an outcome were estimated using the Aalen-Johansen estimate in order to take into account competing risks.

Results

The study cohort comprised 554 ARVC patients. During a median follow-up of 6.0 [3.1,12.5] years, 100 patients (18%) experienced VA (Figure). Risk estimates for VA using the 2019 ARVC risk model showed good discriminative ability (c-statistic 0.75 (95% CI 0.70–0.81)) but with overestimation of risk (slope 0.46 (95% CI 0.33–0.63)). The ARVC risk model was compared in 4 gene groups: PKP2 (n=118, 21%); DSP (n=79, 14%); other desmosomal (n=59, 11%); and gene elusive (n=160, 29%). Discrimination and calibration were highest for PKP2 [c-statistic 0.83 (95% CI 0.75–0.91); calibration slope 0.67 (95% CI 0.40–1.04)] and lowest for the gene elusive group [c-statistic 0.65 (95% CI 0.57–0.74); calibration slope 0.26 (95% CI 0.06–0.49)]. Univariable analyses revealed variable performance of individual clinical risk markers in the different gene groups (see heatmap of hazard ratios and statistical significance in Figure). For example, RV dimensions and systolic function are significant risk markers in PKP2 but not in DSP patients and the opposite is true of LV systolic function (Figure).

Conclusion

The 2019 ARVC risk model performs reasonably well in gene positive ARVC, (particularly for PKP2) but is more limited in gene elusive patients. Genotype specific risk factors should be considered in ARVC patients.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): British Heart Foundation

Natural history of MYH7-related dilated cardiomyopathy

Background

Variants in MYH7 are responsible for disease in 1–5% of patients with dilated cardiomyopathy (DCM); however, the clinical characteristics and natural history of MYH7-related DCM are poorly described.

Objectives

We sought to determine the phenotype and prognosis of MYH7-related DCM. We also evaluated the influence of variant location on phenotypic expression.

Methods

We studied clinical data from 147 individuals with DCM-causing MYH7 variants (47.6% females, 35.6±19.2 years) recruited from 29 international centers.

Results

At initial evaluation, 106 patients (72.1%) had DCM (LVEF 34.5±11.7%). Median follow-up was 4.5 years (interquartile range: 1.7–8.0). 23.7% carriers who were initially phenotype-negative developed DCM. Disease penetrance by 40 and 60 years was 46% and 88%, respectively, with 18 patients (16%) first diagnosed at <18 years. Thirty-six percent of patients with DCM met imaging criteria for LV non-compaction. During follow-up, 28% showed left ventricular reverse remodeling (LVRR). Overall incidence of end-stage heart failure (heart transplantation or heart failure related death) was 11.6% at 5 years. Overall major ventricular arrhythmia rate was low (1.0% at 5 years) even among patients with LVEF ≤35% (2.1% at 5 years). LV non-compaction was more prevalent in patients with variants in head domain (S1) (44.2%) compared with other domains (P<0.001). No differences among domain groups were found regarding LVRR, major ventricular arrhythmias or end-stage heart failure.

Conclusions

MYH7-related DCM is characterized by early age of onset, high penetrance, low rate of LVRR, and frequent progression to ESHF. Heart failure complications predominate over ventricular arrhythmias, even among patients with severe systolic disfunction.

Funding Acknowledgement

Type of funding sources: None.

Outcomes of patients with left ventricular noncompaction and preserved ejection fraction

Funding Acknowledgements

Type of funding sources: None.

INTRODUCTION 

Left ventricular noncompaction (LVNC) is a poorly defined entity with heterogeneous prognosis. LV ejection fraction (LVEF) is one of the main predictors of major adverse cardiovascular events (MACE). However, outcomes of LVNC patients with preserved LVEF (pEF) remain uncertain.

PURPOSE 

The aim of our study was to determine the incidence and predictors of MACE in LVNC patients with pEF as well as to assess the evolution of LVEF throughout follow-up. 

METHODS 

We conducted a retrospective, longitudinal, multicentre cohort study. Consecutive patients with transthoracic echocardiography (TTE) and/or cardiac magnetic resonance (CMR) diagnostic criteria for LVNC and initially pEF (LVEF≥50%) were recruited. MACE were defined as a composite of heart failure (HF), ventricular arrhythmias (VA), systemic embolisms (SE) and/or all-cause mortality. Progressive systolic dysfunction was defined as an LVEF < 50% at last TTE and/or an absolute ≥10-point decrease in LVEF from first to last TTE. Lower limit of LVEF CMR values were considered 50-57% according to current recommendations. Cox-regression analysis was used for MACE and logistic regression was used for progressive systolic dysfunction (only first and last TTE were available).

RESULTS 

A total of 305 patients from 12 centres were included from 2000 to 2018. Age was 38 ± 19 years and 165 (54%) were men. LVEF was 62 ± 8% and 8% had late gadolinium enhancement (LGE). During a median follow-up of 4.7 (IQR 2.1-7.4) years, MACE occurred in 40 (13%) patients with an incidence rate of 2.73 (95% CI 2.00-3.72) events per 100 person-years: 8 HF, 27 VA, 3 SE and 5 deaths. LVEF by CMR (HR 0.95, 95% CI 0.91-0.99, p = 0.0048) and hypertension (HR 2.30, 95% CI 1.08-4.89, p = 0.031) were the only variables independently associated with the endpoint. Patients with lower limit LVEF values showed an increased risk of MACE (Figure 1). LGE was not associated.

Sixty-one (21%) patients experienced progressive systolic dysfunction: 31 (11%) had an LVEF < 50% and 48 (17%) an absolute ≥10-point decrease in LVEF at last follow-up. On multivariate analysis, LVEF by CMR was the only independent predictor (OR 0.93, 95% CI 0.89-0.98, p = 0.008). Patients with lower limit LVEF values had an increased risk (Figure 2). In this subgroup, LGE was also associated with the endpoint (HR 10.69, 95% CI 1.97-58.13, p = 0.006).

CONCLUSIONS 

Patients with left ventricular noncompaction and preserved ejection fraction carry a moderate risk of major adverse cardiovascular events and progressive systolic dysfunction. LVEF remains the main predictor of outcomes in this subgroup. Patients with lower limit LVEF values are at increased risk, probably suggesting subclinical systolic dysfunction. Therefore, they should be carefully monitored. Abstract Figure. Kaplan Meier cuves for MACE  Abstract Figure. Risk of progressive systolic dysfunction

Prognostic role of cardiac magnetic resonance in left ventricular noncompaction

Funding Acknowledgements

Type of funding sources: None.

Background

Left ventricular noncompaction (LVNC) is a heterogeneous entity with a wide phenotypic expression. Risk factors have not been well established and prognostic stratification remains challenging.

Purpose

Describe prognostic role of CMR on long term outcomes of LVNC patients. 

Methods

 

Retrospective multicentric longitudinal cohort study of consecutive patients fulfilling imaging diagnostic criteria for LVNC (Jenni echo criteria and Petersen and Jacquier CMR criteria). Demographic, ECG, genetic, family and treatment variables were recorded. Baseline CMR was used for the analysis. LV ejection fraction (LVEF) was categorized according to heart failure (HF) guidelines and late gadolinium enhancement (LGE) was visually assessed in a binary way. End points were HF, ventricular arrhythmias (VA), systemic embolisms (SE) and all-cause death. Major adverse cardiovascular events (MACE) were the combination of the four previous end points. In patients with initially preserved LVEF (≥ 50%), LV adverse remodelling (LVAR) was defined as an LVEF < 50% and/or absolute decrease of ≥10% in LVEF at last follow-up.

Results

585 patients from 12 referral centres were included from 2000 to 2018. Age at diagnosis was 45 ± 20 years, 334 (57%) were male, baseline LVEF was 48 ± 17% and 18% presented LGE. During a median follow-up of 5.1 years (IQR 2.3-8.1), 110 (19%) patients presented HF, 87 (15%) VA, 18 (3%) SE and 34 (6%) died. MACE occurred in 223 (38%) patients.

LVEF was independently associated with HF, VA, SE and MACE: HR were 1.08, 1.02, 1.04 and 1.02 respectively (all p < 0.05). LGE was more frequent in patients with reduced LVEF (39 Vs 53%, p < 0.001) and was associated with higher HF and VA risk in patients with an LVEF > 35% (HR 2.69 and 2.48 respectively, p < 0.05) (Figure 1). No MACE (0%) occurred during long-term follow-up in patients with preserved LVEF, no LGE as well as no ECG abnormalities and no family aggregation.

305 (52%) patients presented with initially preserved LVEF, and 230 (75%) of those had LVEF available at last follow-up. LVAR occurred in 50 (22%) patients: 22 (10%) had an LVEF < 50% and 41 (18%) an absolute ≥ 10% decrease in LVEF. LGE was independently associated with LVAR (HR 3.51, p = 0.045) (Figure 2). 

Conclusions

Cardiac magnetic resonance has an important prognostic role in LVNC. LVEF is the most powerful predictor of events. Myocardial fibrosis is associated with worse outcomes in patients without severe systolic dysfunction, as well as with left ventricular adverse remodelling in those with initially preserved LVEF. Besides, CMR may identify a low-risk subgroup of LVNC patients. Therefore, CMR should be used in risk stratification in LVNC.

P5555Predictors of systemic embolisms in a large cohort of left ventricular noncompaction patients

Background

Left ventricular noncompaction (LVNC) is associated with an increased risk of systemic embolisms (SE). However, incidence and risk factors are not well established.

Purpose

To evaluate the rate of SE in LVNC and describe risk factors.

Methods

LNVC patients were included in a multicentric registry. Those with SE were considered for the analysis.

Results

514 patients with LVNC from 10 Spanish centres were recruited from 2000 to 2018. During a median follow-up of 4.2 years (IQR 1.9–7.1), 23 patients (4.5%) had a SE. Patients with SE (Table 1) were older at diagnosis, with no differences in gender and had similar cardiovascular risk factors. They were more frequently under oral anticoagulation (OAC). Besides, they had a more reduced LVEF, and more dilated LV and left atrium (LA). Late gadolinium enhancement (LGE) was more frequent, altogether suggesting a more severe phenotype.

Patients with SE had non-significantly higher rates of hospitalization for heart failure (33% vs 24%, p=0.31) and atrial fibrillation (35% vs 19%, p=0.10). In multivariate analysis, only LA diameter was an independent predictor of SE (OR 1.04, p=0.04). A LA diameter>45 mm had an independent 3 fold increased risk of SE (OR 3.04, p=0.02) (Image 1).

Table 1 Systemic embolisms (n=23) No systemic embolisms (n=491) p Men, n (%) 15 (65) 289 (56) 0.52 Median age at diagnosis (IQR), yr 60 (48–76) 48 (30–64) 0.02 Median follow up (IQR), yr 5.9 (3.1–7.8) 4.2 (1.8–7.1) 0.18 Hypertension, % 8 (33) 118 (24) 0.31 Diabetes mellitus, % 3 (14) 39 (8) 0.41 OAC, % 19 (83) 118 (24) 0.01 LVEF (SD), % 37 (15) 48 (17) 0.01 LVEDD (SD), mm 58 (11) 54 (10) 0.04 LVESD (SD), mm 45 (13) 38 (11) 0.01 LA diameter (SD), mm 46 (9) 39 (9) 0.01 LVEDV CMR (SD), mL 193 (75) 163 (70) 0.12 LVESV CMR (SD), mL 121 (64) 85 (64) 0.04 LGE, % 9 (40) 88 (18) 0.04

Conclusions

LVNC carries a moderate mid-term risk of SE, which appears to be irrespective of atrial fibrillation and associated with age, LV dilatation and systolic dysfunction and mainly LA dilatation. This subgroup of patients should be considered for oral anticoagulation in primary prevention.

Endothelial progenitor cells in cell-based therapy for cardiovascular disease

Coronary Artery Diseases (CAD) is the first mortality cause in industrialized countries. The possibility of regenerating myocardium injured tissue using the cell therapy is a promising option to regenerate cardiac tissue. Currently, a variety of adult stem/ progenitor cells are undergoing clinical evaluation, but it is very important to study and characterize the bone marrow-derived progenitor/ stem cells, the main source of cells used for human cardiac repair, before their clinical use. Bone marrow-derived endothelial progenitor cells (EPC) home sites of ischemia and differentiate into endothelial cells, increase the neovascularization of ischemic tissue. Moreover recently, it has been observed that EPC can be able to differentiate or transdifferentiate to like-adult cells resident in cardiac tissues. The characterization of phenotype EPC is complex, because express hematopoietic stem cells (CD133 and/or CD34) and endothelial markers such as vascular endothelial growth factor receptor 2 (KDR). Several studies described subpopulation of EPC expressing CD34+D133+KDR+ phenotype in literature, but some other authors suggest other phenotype. The EPC capacity of mobilization or recruitment/ homing to ischemic tissue areas by cytokines are reviewed. Finally are described clinical studies in CAD using bone marrow-derived progenitor cells permitting human cardiac tissue repair.