Interrelationship between the Myocardial Mass, Fibrosis, BNP, and Clinical Outcomes in Hypertrophic Cardiomyopathy

Cardiac imaging and biomarkers for assessing myocardial fibrosis in children with hypertrophic cardiomyopathy

BACKGROUND

Myocardial fibrosis, as diagnosed on cardiac magnetic resonance imaging (cMRI) by late gadolinium enhancement (LGE), is associated with adverse outcomes in adults with hypertrophic cardiomyopathy (HCM), but its prevalence and magnitude in children with HCM have not been established. We investigated: (1) the prevalence and extent of myocardial fibrosis as detected by LGE cMRI; (2) the agreement between echocardiographic and cMRI measurements of cardiac structure; and (3) whether serum concentrations of N-terminal pro hormone B-type natriuretic peptide (NT-proBNP) and cardiac troponin-T are associated with cMRI measurements.

METHODS

A cross-section of children with HCM from 9 tertiary-care pediatric heart centers in the U.S. and Canada were enrolled in this prospective NHLBI study of cardiac biomarkers in pediatric cardiomyopathy (ClinicalTrials.gov Identifier: NCT01873976). The median age of the 67 participants was 13.8 years (range 1-18 years). Core laboratories analyzed echocardiographic and cMRI measurements, and serum biomarker concentrations.

RESULTS

In 52 children with non-obstructive HCM undergoing cMRI, overall low levels of myocardial fibrosis with LGE >2% of left ventricular (LV) mass were detected in 37 (71%) (median %LGE, 9.0%; IQR: 6.0%, 13.0%; range, 0% to 57%). Echocardiographic and cMRI measurements of LV dimensions, LV mass, and interventricular septal thickness showed good agreement using the Bland-Altman method. NT-proBNP concentrations were strongly and positively associated with LV mass and interventricular septal thickness (P < .001), but not LGE.

CONCLUSIONS

Low levels of myocardial fibrosis are common in pediatric patients with HCM seen at referral centers. Longitudinal studies of myocardial fibrosis and serum biomarkers are warranted to determine their predictive value for adverse outcomes in pediatric patients with HCM.

The evolving paradigm and current perception of hypertrophic cardiomyopathy: Implications for management

Recent evidence from imaging and genetic screening studies has clearly shown that hypertrophic cardiomyopathy (HCM) is more common than initially perceived, emphasizing the need to reassess its associated clinical and social burden. While clinical and academic efforts have long been focused on stratification of arrhythmic risk and management of intraventricular obstruction, progression of cardiac dysfunction and heart failure-related complications have emerged as most relevant from the epidemiological standpoint, delineating a major unmet need. Furthermore, a broader perspective of our patients' needs has become central in the care of individuals with HCM, addressing issues that are not strictly clinical but equally important to their wellbeing, such as quality of life, athletic participation, lifestyle and reproductive choices and psychological adaptation to a chronic condition often detected at a young age. The appropriate evaluation and objective assessment of disease burden associated with HCM are increasingly relevant not only to management but also to trial design and evaluation of the efficacy of emerging, targeted treatments. In this review, we discuss the evolving perception of HCM prevalence and natural history, as well as recent acquisitions regarding its true, often under-appreciated socio-economic and clinical burden.

Body composition and mortality in a cohort study of Chinese patients with hypertrophic cardiomyopathy

Objective

To analyse the characteristics and mortality of hypertrophic cardiomyopathy (HCM) patients with different body compositions.

Methods

In this study, 530 consecutive patients with HCM at West China Hospital were studied from November 2008 to May 2016. An equation based on body mass index (BMI) was used to obtain the Percent body fat (BF) and lean mass index (LMI). Patients were divided into five sex-specific BMI, BF and LMI quintiles.

Results

The average BMI, BF and LMI were 23.1 ± 3.2 kg/m2, 28.1 ± 7.3% and 16.5 ± 2.2 kg/m2, respectively. Patients with higher BMI or BF were older and had more symptoms and adverse cardiovascular conditions; those with higher LMI were younger and had less coronary artery disease and lower serum NT-proBNP and creatine. BF correlated positively with resting left ventricular (LV) outflow tract gradient, mitral regurgitation (MR) degree and left atrial diameter but was inversely associated with septal wall thickness (SWT), posterior wall thickness (PWT), LV mass, and E/A ratio; LMI was positively correlated with SWT, LV end diastolic volume and LV mass but was negatively associated with MR degree.48 all-cause deaths occurred during a median follow-up of 33.8 months. Reversed J-shape associations of BMI and LMI with mortality were observed. A lower BMI or LMI was significantly associated with high mortality, especially for low-moderate BMI and LMI. No significant difference in mortality was found across BF quintiles.

Conclusions

The associations of BMI, BF and LMI with baseline characteristics and cardiac remodelling are different in HCM patients. In Chinese HCM patients, low BMI and LMI predicted mortality but not BF.

Evaluation of Left Ventricular Mass in Different Cardiac Geometry Using Three-Dimensional Contrast-Enhanced Echocardiography

A total of 69 patients were enrolled in the study, including 23 patients with hypertrophic cardiomyopathy (HCM), 26 patients with Left Ventricle (LV) enlargement comprising 16 dilated cardiomyopathy (DCM) patients and 10 ischemic cardiomyopathy (ICM) patients, and 20 control subjects. All patients underwent 2DE, contrast-enhanced 2DE (Contrast-2DE), 3DE, Contrast-3DE, and single photon emission computed tomography (SPECT) examinations. The 2DE-AL and 3DE methods measured the left ventricular mass (LVM). The results were compared with those measured by SPECT. The measured LVM of the 69 patients was systematically overestimated by 2DE-AL (177.4 ± 56.2 g), Contrast-2DE-AL (174.5 ± 55.5 g), 3DE (167.3 ± 59.2 g), and Contrast-3DE (154.2 ± 46.7 g) when compared with SPECT (148.5 ± 52.4 g) (P < 0.05), while Contrast-3DE provided the best agreement with SPECT in LVM measurement (r = 0.898, P < 0.001) and had the smallest deviation (5.7 ± 23.1 g). 3DE overestimated LVM more compared to Contrast-3DE in LV hypertrophy group (165.5 ± 37.9 g versus 153.5 ± 27.6 g, P = 0.003) and LV enlargement group (204.5 ± 69.3 g versus 183.5 ± 53.5 g, P = 0.006). For 2DE methods, there was no significant difference between the LVM obtained with or without contrast enhancement in control group (132.3 ± 23.6 g versus 128.4 ± 23.3 g), LV hypertrophy group (177.7 ± 38.6 versus 178.3 ± 30.9 g, P = 0.889), and LV enlargement group (211.9 ± 63.2 g versus 206.5 ± 66.0 g, P = 0.386). The difference between LVM measured by 2DE-AL and SPECT was the greatest (27.9 ± 34.0 g), especially in LV hypertrophy group and LV enlargement group (LV hypertrophy group 39.7 ± 26.0 g; LV enlargement group 24.2 ± 42.8 g). To conclude, Contrast-3DE and SPECT show greater consistency in LVM measurement, especially in cardiomyopathy, when compared with 2DE. Administering contrast can effectively reduce the overestimation of LVM by non-contrast DE.

The association of left ventricular histologically verified myocardial fibrosis with pulmonary hypertension in severe aortic stenosis

OBJECTIVES

To evaluate the association between histologically verified left ventricular (LV) myocardial fibrosis (MF) and its bio- and functional markers with pulmonary hypertension (PH) in severe aortic stenosis (AS).

METHODS

About 34 patients with isolated severe AS underwent 2D echocardiography, cardiac magnetic resonance (CMR) imaging, and plasma NT-proBNP evaluation before aortic valve replacement (AVR). LV measurements were analyzed by CMR and LV strain using feature tracking software (Medis Suite QStrain 2.0). Myocardial biopsy sampled at the time of AVR was assessed by a histomorphometric analysis. PH was defined as pulmonary artery systolic pressure (PASP) ⩾ 45 mm Hg.

RESULTS

Patients with severe AS and PH (mean PASP 53 ± 3.7 mm Hg) had higher extent of diffuse MF versus patients without PH (12 (10.4-12.7)% vs 6.6 (4.6-8.2)% (p = 0.00)). The extent of diffuse MF correlated with LV dilatation (r = 0.7, p = 0.02), indices of LV dysfunction (lower ejection fraction (r = -0.6, p < 0.001), global longitudinal (r = -0.5, p = 0.02) and circumferential strain (r = -0.5, p = 0.05), elevated NT-proBNP (r = 0.5, p = 0.005) and elevated PASP (r = 0.6, p < 0.001)). Histological MF > 10% (AUC 94.9%), LV global longitudinal strain > -15.5% (AUC 86.3%), and NT-proBNP > 2090 ng/l (AUC 85.1%) were independent predictors of PH in severe AS.

CONCLUSIONS

The extent of diffuse myocardial fibrosis in combination with reduced longitudinal left ventricular strain and increased plasma levels of NT-proBNP relates to pulmonary hypertension in severe aortic stenosis.

Circulating Biomarkers in Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is the most common genetic heart disease. Biomarkers, molecules measurable in the blood, could inform the clinician by aiding in diagnosis, directing treatment, and predicting outcomes. We present an updated review of circulating biomarkers in hypertrophic cardiomyopathy representing key pathologic processes including wall stretch, myocardial necrosis, fibrosis, inflammation, hypertrophy, and endothelial dysfunction, in addition to their clinical significance.

Sex Differences in Time-Dependent Changes in B-Type Natriuretic Peptide in Hypertrophic Cardiomyopathy

Background: Female sex is reported to be associated with poor prognosis in hypertrophic cardiomyopathy (HCM). The plasma B-type natriuretic peptide (BNP) concentration is a prognostic predictor in HCM. However, the effect of sex on BNP concentrations remains unclear among HCM patients.

Methods and Results: Patient records in the Clinical Personal Records of HCM national database of the Japanese Ministry of Health, Labour and Welfare from 2009 to 2014 were analyzed. Of 3,570 HCM patients, 611 in whom BNP concentrations were assessed at both baseline and the 2-year follow-up were included in this analysis. The mean age was 60.4 years and 254 (41.6%) patients were female. Median (interquartile range) BNP concentrations were higher in females than males at both baseline (320.3 [159.0–583.1] vs. 182.8 [86.1–363.9] pg/mL; P<0.001) and the 2-year follow-up (299.2 [147.0–535.3] vs. 161.0 [76.2–310.0] pg/mL; P<0.001). Female sex was associated with higher natural log-transformed BNP at the 2-year follow-up regardless of clinical characteristics, including echocardiographic findings and BNP concentrations at baseline (coefficient 0.31; 95% confidence interval 0.13–0.48; P<0.001). Cubic spline analysis showed that, among patients with high BNP concentrations at baseline, females had higher BNP concentrations at the 2-year follow-up than males.

Conclusions: In HCM, female sex was associated with higher BNP concentrations than male sex, independent of clinical characteristics, including BNP concentrations at baseline.

Atrial Fibrillation in Hypertrophic Cardiomyopathy: Evidence-based Review About Mechanism, Complications and Management

Hypertrophic cardiomyopathy (HCM) is 1 of the most frequent genetic cardiovascular diseases affecting 1 out of every 500 individuals in general population. Atrial Fibrillation incidences were 3.8% per 100 patients per year and overall prevalence among HCM patients are 27.09%. Higher risk of death noted in HCM patients with atrial fibrillation. Stroke and other thrombo embolic risks are increased in such patients. Medical management using mainly betablockers or amiodarone produced variable results and high rate of recurrence. Catheter ablation reduced symptom burden and complications despite moderate recurrence. Patients with multiple repeated procedures found to have better success rate and outcomes. The complications are not high leading to increased feasibility of the procedure. More research using latest techniques in catheter ablation need to be studied.

Increased Left Ventricular Trabeculation Is Associated With Increased B-Type Natriuretic Peptide Levels and Impaired Outcomes in Nonischemic Cardiomyopathy

BACKGROUND

The clinical significance of left ventricular (LV) trabeculation remains unknown in cardiomyopathies. B-Type natriuretic peptide (BNP) strongly reflects LV end-diastolic wall stress and is a useful prognostic marker of cardiovascular diseases. The enhanced identification of LV trabeculae (T) with the use of cardiac magnetic resonance and the evaluation of its relationship with BNP may elucidate the biologic significance and clinical impact of trabeculation in patients with nonischemic cardiomyopathy (NICM).

METHODS

The LV volume and mass of 515 patients with NICM and 36 control subjects were analyzed with the use of a steady-state free precession sequence, and individual T mass was planimetred. Major adverse cardiac events (MACE) were assessed.

RESULTS

T mass index correlated with LV end-diastolic volume index (EDVI), LV mass index, and papillary muscle mass index (all P < 0.001). Also, T mass index was positively correlated with BNP level (R = 0.381; P < 0.001) and was an independent determinant of BNP after adjusting for age, sex, body mass index (BMI), etiology, LV ejection fraction, and LV EDVI (P < 0.001). Kaplan-Meier analysis during a median follow-up of 17.3 months showed that higher T mass index and increased BNP level correlated with MACE. On multivariate analysis, T mass index (P = 0.031) and BNP (P < 0.001) remained associated with poor outcomes when combined with age, sex, BMI, and etiology.

CONCLUSIONS

Increased LV trabeculation was associated with LV dysfunction/remodelling and impaired outcomes in NICM of various etiologies. This may support the biologic significance of LV trabeculation and could be attributed to its association with BNP through LV wall stress.

Combined Assessment of the Red Cell Distribution Width and B-type Natriuretic Peptide: A More Useful Prognostic Marker of Cardiovascular Mortality in Heart Failure Patients

Objective An increased red cell distribution width (RDW) has been reported to be associated with adverse outcomes in patients with heart failure (HF). This study aimed to evaluate the prognostic power of the combined measurement of RDW and B-type natriuretic peptide (BNP) concentrations in patients with HF. Methods and Results We retrospectively studied 116 patients (mean age, 63.7±14.3 years) who were admitted for the treatment of HF. Data including demographic information, vital signs, and laboratory and echocardiographic measurements at admission were collected from medical records. The observational period was defined as the number of days from hospitalization, and the study endpoint was defined as cardiovascular death. The mean RDW and BNP concentration at admission were 14.5±2.0% and 626±593 pg/mL, respectively. During a median observation period of 1,046 days, 22 patients died of cardiovascular disease. A univariate Cox proportional hazard analysis revealed that both RDW [hazard ratio (HR) 1.252, p = 0.0391] and BNP (HR 1.001, p = 0.0445) were significant prognostic indices for cardiovascular death. A receiver operating characteristic curve analysis revealed that the optimal cut-off RDW and BNP values for cardiovascular death were 14.9% and 686 pg/mL, respectively. The Kaplan-Meier survival curve revealed that the survival rate of patients with both RDW ≥ 14.9% and BNP ≥ 686 pg/mL showed the poorest prognosis in comparison to the patients in the other groups. Conclusion The combined assessment of the RDW and BNP concentrations may be useful for predicting mortality in patients with HF.