B-type natriuretic peptide and outcome in patients with apical hypertrophic cardiomyopathy

Relationship between left atrial/left ventricular diameter ratio and outcomes in patients with hypertrophic cardiomyopathy

BACKGROUND

Although diastolic dysfunction is the main pathophysiological feature of hypertrophic cardiomyopathy (HCM), it remains to be clarified whether parameters of diastolic function can reliably determine HCM prognosis. In patients with reduced left ventricular (LV) distensibility, chronic elevation of LV diastolic pressure is seen with a smaller than expected LV size. Accordingly, patients with HCM with severe LV diastolic dysfunction typically demonstrate left atrial (LA) dilation and a disproportionately smaller left ventricle. Therefore, we investigated the relationship between LA/LV diameter ratio, as a potential indicator of disease progression, and outcomes in patients with HCM.

METHODS

We included 468 patients in whom LA and LV end-diastolic diameter were successfully evaluated by echocardiography at the initial assessment. We divided the patients into two groups: those with an LA/LV diameter ratio > 1 and those with an LA/LV diameter ratio ≤ 1. We compared the HCM-related death rates between the two groups.

RESULTS

Of the 468 patients, 96 patients (20.5 %) with HCM showed an LA/LV diameter ratio > 1. In the univariate analysis, patients with an LA/LV diameter ratio > 1 had a significantly greater likelihood of HCM-related death than patients with an LA/LV diameter ratio ≤ 1 (log-rank p = 0.002). In the multivariate Cox proportional hazards analysis, when including LA/LV diameter ratio > 1 and imbalanced baseline variables, an LA/LV diameter ratio > 1 was an independent determinant of HCM-related death (adjusted hazard ratio: 1.87, 95 % confidence interval: 1.08-3.24; p = 0.024).

CONCLUSION

LA/LV diameter ratio can be easily evaluated and may be useful for risk stratification of HCM-related death in patients with HCM.

Effect of Mavacamten in Women Compared With Men With Obstructive Hypertrophic Cardiomyopathy: Insights From EXPLORER-HCM

BACKGROUND

Compared with men, women with hypertrophic cardiomyopathy (HCM) have a higher incidence of heart failure and worse outcomes. We investigated baseline clinical and echocardiographic characteristics and response to mavacamten among women compared with men in the EXPLORER-HCM study (Clinical Study to Evaluate Mavacamten [MYK-461] in Adults With Symptomatic Obstructive Hypertrophic Cardiomyopathy).

METHODS

A prespecified post hoc analysis of sex from the blinded, randomized EXPLORER-HCM trial of mavacamten versus placebo in symptomatic patients with obstructive HCM was performed. Baseline characteristics were compared with t tests for continuous variables (expressed as mean values) and χ2 tests for categorical variables. Prespecified primary, secondary, and exploratory end points and echocardiographic measurements from baseline to end of treatment (week 30) were analyzed with ANCOVA for continuous end points and a generalized linear model with binomial distribution for binary end points, with adjustment for each outcome's baseline value, New York Heart Association class, β-blocker use, and ergometer type.

RESULTS

At baseline, women (n=102) were older (62 years versus 56 years; P<0.0001), had lower peak oxygen consumption (16.7 mL·kg-1·min-1 versus 21.3 mL·kg-1·min-1; P<0.0001), were more likely to be assigned New York Heart Association class III (42% versus 17%; P<0.0001), had worse health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 64 versus 75; P<0.0001), and had higher baseline plasma NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels (1704 ng/L versus 990 ng/L; P=0.004) than men (n=149). After 30 weeks of mavacamten treatment, similar improvements were observed in women and men in the primary composite end point (percentage difference on mavacamten versus placebo, 22% versus 19%, respectively; P=0.759) and in the secondary end points of change in postexercise left ventricular outflow tract gradient (-42.4 mm Hg versus -33.6 mm Hg; P=0.348), change in peak oxygen consumption (1.2 mL·kg-1·min-1 versus 1.6 mL·kg-1·min-1; P=0.633), and percentage achieving ≥1 New York Heart Association class improvement (41% versus 28%; P=0.254). However, women had greater improvement in health status (Kansas City Cardiomyopathy Questionnaire-Clinical Summary Score 14.8 versus 6.1; P=0.026) and in the exploratory end point of NT-proBNP levels (-1322 ng/L versus -649 ng/L; P=0.0008).

CONCLUSIONS

Although at baseline women with symptomatic obstructive HCM enrolled in EXPLORER-HCM were older and had worse heart failure and health status than men, treatment with mavacamten resulted in similar improvements in the primary and most secondary EXPLORER-HCM end points and greater improvements in health status and NT-proBNP.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03470545.

Prevalence, characteristics, and natural history of apical phenotype in a large cohort of patients with hypertrophic cardiomyopathy

BACKGROUND

Apical hypertrophic cardiomyopathy (ApHCM) is a variant of hypertrophic cardiomyopathy (HCM) with distinct imaging and clinical characteristics. Data on the prognosis of this HCM subgroup appear conflicting. Our study aims to clarify the natural history of ApHCM and identify predictors of outcomes.

MATERIALS AND METHODS

A total of 856 patients with HCM were retrospectively examined. ApHCM was defined as asymmetric left ventricular hypertrophy confined predominantly at the apex, either isolated (pure ApHCM type) or with co-existent hypertrophy of the interventricular septum (mixed ApHCM). Echocardiographic, clinical, and survival data were compared between individuals with ApHCM and non-ApHCM.

RESULTS

A total of 143 (16.7%) patients were diagnosed with ApHCM. Compared with non-ApHCM, subjects with apical HCM were diagnosed at an older age and had better echocardiographic indices and more comorbidities at baseline. Apical aneurysms were more prevalent among the ApHCM phenotype (6.3% vs. 1.7%, p = 0.003). During a mean follow-up of 6 ± 3 years, ApHCM was characterized by lower all-cause, cardiovascular, heart failure-related mortality, and ventricular arrhythmic events compared with non-ApHCM. Multivariate analysis identified atrial fibrillation and HCM risk-sudden cardiac death (SCD) as independent predictors of the composite outcome of overall mortality and hospitalizations for cardiovascular reasons (hazard ratio [HR] 4.3, 95% confidence interval [CI] 1.9-9.5 for atrial fibrillation and HR 1.2, 95% CI 1.02-1.3 for HCM risk-SCD) in ApHCM.

CONCLUSIONS

ApHCM exhibited a lower rate of all-cause mortality and arrhythmic events in the middle-aged population of patients with HCM. Atrial fibrillation and HCM risk-sudden cardiac death were independent predictors of a composite of overall mortality and cardiovascular hospitalizations among those with ApHCM.

Circulating N-Terminal Probrain Natriuretic Peptide Levels in Relation to Ischemic Stroke and Its Subtypes: A Mendelian Randomization Study

Mendelian randomization was used to evaluate the potential causal association between N-terminal probrain natriuretic peptide (NT-proBNP) and ischemic stroke based on summary statistics data from large-scale genome-wide association studies. Three single-nucleotide polymorphisms (SNPs) rs198389, rs13107325, and rs11105306 associated with NT-proBNP levels found in large general populations and in patients with acute heart disease were used as instrumental variables. The results of genetic association analysis of each single SNP show that there is no significant association between NT-proBNP levels and ischemic stroke or its subtypes, whereas rs198389 alone has a suggestive association with large-artery atherosclerosis stroke. The MR analysis of three SNPs shows that NT-proBNP levels may reduce the risk of small-vessel occlusion stroke suggestively. This genetic analysis provides insights into the pathophysiology and treatment of ischemic stroke.

N-terminal pro-brain natriuretic peptide and adverse outcomes in Chinese patients with hypertrophic cardiomyopathy

Background: Although numerous studies have suggested that elevated N-terminal pro-brain natriuretic peptide (NT-proBNP) is positively correlated with cardiovascular events, especially the heart failure and heart failure-related death (HFRD), evidence of the association between NT-proBNP and the adverse outcomes of hypertrophic cardiomyopathy (HCM) is still relatively limited. The present study was performed to evaluate the relationship between NT-proBNP and outcomes in patients with HCM.

Methods: Observational cohort methodology was used in the present study, and a total of 227 patients were included. And the patients were followed for 44.97 ± 16.37 months. Patients were categorized into three groups according to these NT-proBNP tertiles: first tertile (≤910 pg/ml, n=68), second tertile (913–2141 pg/ml, n=68), and third tertile (≥2151 pg/ml, n=69). The adverse outcomes of the present study were all-cause death (ACD) and cardiac death (CD).

Results: According to the risk category of NT-proBNP, the incidence of ACD (P=0.005) and CD (P=0.032) among the three groups showed significant differences. Multivariate Cox regression analysis suggested that the ACD and CD in the third tertile have 7.022 folds (hazard risk [HR] = 7.022 [95% confidence interval [CI]: 1.397–35.282], P=0.018) and 7.129 folds (HR = 7.129 [95% CI: 1.329–38.237], P=0.022) increased risks as compared with those in the first tertile. Kaplan–Meier survival analyses showed that the cumulative risks of ACD and CD in patients with HCM tended to increase.

Conclusion: The present study indicated NT-proBNP was a novel biomarker suitable for predicting adverse prognosis in patients with HCM, which may be used for early recognition and risk stratification.