Increased Levels of Cardiac Troponin I in Subjects with Extremely Low B-type Natriuretic Peptide Levels

Concentric hypertrophy geometry is a significant determinant of impaired global longitudinal strain in patients with normal cardiac structure and function

Background

In recent years, the assessment of global longitudinal strain (GLS) derived by speckle-tracking analysis has become a clinically feasible alternative to left ventricular (LV) ejection fraction (LVEF) for the assessment of myocardial function. However, the determinant factors of impaired GLS in structurally and functionally normal patients are unclarified. The objective of this study was to elucidate the determinant factors of impaired GLS in structurally and functionally normal patients.

Methods

We evaluated structurally and functionally normal patients scheduled to undergo noncardiac surgery. The evaluated patient characteristics were age, sex, presence of hypertension, presence of diabetes mellitus, presence of hyperlipidemia, systolic blood pressure, and body mass index. The concentrations of B-type natriuretic peptide and high-sensitivity troponin I were measured. Echocardiography was performed to determine the LVEF, GLS, transmitral early diastolic velocity/transmitral atrial velocity ratio, LV mass index (LVMI), and relative wall thickness (RWT). Patients with preserved LVEF (≥50%) were divided into the normal GLS group (GLS ≤ -20%) and the impaired GLS group (GLS > -20%). On the basis of the RWT and LVMI values, the patients were categorized as having four types of LV geometry. Logistic regression analysis was performed to ascertain the determinant factors of impaired GLS.

Results

The study cohort comprised 75 structurally and functionally normal patients (age 67.7 ± 12.6 years, 45 men). The GLS was normal in 43 patients and impaired in 32 patients. There was a significant difference in RWT between the impaired and normal GLS groups. The evaluation based on the LV geometry showed that six of seven patients with concentric hypertrophy geometry had impaired GLS, and the GLS was significantly more impaired in patients with concentric hypertrophy geometry than in patients with normal geometry or eccentric hypertrophy geometry. Logistic regression analysis revealed that LV concentric hypertrophy geometry was a significant determinant factor of impaired GLS (odds ratio 22.4, P = 0.042).

Conclusions

Global longitudinal strain is more impaired in structurally and functionally normal patients with concentric hypertrophy geometry compared with those with eccentric hypertrophy geometry or normal geometry. In addition, concentric hypertrophy geometry is a significant determinant for impaired GLS in patients with normal cardiac structure and function.

The Predictive Value of A, B, and C-Type Natriuretic Peptides in People at Risk of Heart Disease: Protocol for a Longitudinal Observational Study

BACKGROUND

Heart disease and stroke are major and often unheralded causes of serious morbidity and premature death in middle age. Early detection of those most at risk is an urgent unmet need for instituting preventative measures. In an earlier community study (Canterbury Health, Ageing and Life Course [CHALICE]) of healthy people aged 50 years, contrary to previous reports, low levels of the heart hormone B-type natriuretic peptide (BNP) were associated with reduced measures of heart function and higher markers of vascular risk. A specific gene variant (rs198358) was found to be an independent contributor to higher BNP levels. A closely related vascular hormone (C-type natriuretic peptide [CNP]) showed opposite associations-higher levels were correlated with higher vascular risk and reduced cardiac function. To determine whether these novel findings predict serious heart or vascular disease in later life, this proposal re-examines the same CHALICE participants 15 years later.

OBJECTIVE

The primary objective is to determine the predictive value of (1) low plasma concentrations of the circulating cardiac hormones (atrial natriuretic peptide [ANP] and BNP) and (2) high levels of the vascular hormone CNP at age 50 years in detecting impaired cardiac and vascular function 15 years later. Secondary objectives are to determine specific associations of individual analytes (ANP, BNP, CNP, cyclic guanosine monophosphate [cGMP]) with echo-derived changes in cardiac performance at ages 50 years and 65 years.

METHODS

All of the 348 participants (205/348, 58.9% female; 53/348, 15.2% Māori or Pacifica ethnicity) participating in the original CHALICE study-free of history of heart or renal disease at age 50 years and who consented to further study-will be contacted, recruited, and restudied as previously described. Data will include intervening health history, physical examination, heart function (speckle-tracking echocardiography), vascular status (carotid intimal thickness), and genetic status (genome-wide genotyping). Laboratory measures will include fasting blood sampling and routine biochemistry, ANP, BNP, CNP, their downstream effector (cGMP), and their bio-inactive products. Humoral metabolic-cardiovascular risk factors will be measured after an overnight fast. Primary outcomes will be analyzed using multiple linear regression.

RESULTS

The study will commence in 2022 and be completed in 2024.

CONCLUSIONS

Proving our hypothesis-that low BNP and high CNP at any age in healthy people predict premature aging of heart and blood vessels, respectively-opens the way to early detection and improved outcomes for those most at risk. Confirmation of our hypotheses would improve current methods of screening and, in appropriate cases, enable interventions aimed at increasing natriuretic hormones and reducing risk of serious cardiovascular complications using drugs already available. Such advances in detection, and from interventional corrections, have the potential to not only improve health in the community but also reduce the high costs inevitably associated with heart failure.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/37011.

Close linkage between blood total ketone body levels and B-type natriuretic peptide levels in patients with cardiovascular disorders

In patients with cardiovascular disorders, blood total ketone body (TKB) levels increase with worsening heart failure and are consumed as an alternative fuel to fatty acid and glucose. We investigated factors contributing to the increase in the blood TKB levels in patients with cardiovascular disorders. The study population consisted of 1030 consecutive patients who underwent cardiac catheterization. Covariance structure analyses were performed to clarify the direct contribution of hemodynamic parameters, including the left ventricular end-diastolic pressure (LVEDP), left ventricular end-systolic volume index (LVESVI), left ventricular end-diastolic volume index (LVEDVI), and B-type natriuretic peptide (BNP) levels, to TKB by excluding other confounding factors. These analyses showed that the TKB levels were significantly associated with the BNP level (P = 0.003) but not the LVEDP, LVESVI, or LVEDVI levels. This was clearly demonstrated on a two-dimensional contour line by Bayesian structure equation modeling. The TKB level was positively correlated with the BNP level, but not LVEDP, LVESVI or LVEDVI. These findings suggested that elevated blood TKB levels were more strongly stimulated by the increase in BNP than by hemodynamic deterioration. BNP might induce the elevation of TKB levels for use as an important alternative fuel in the failing heart.

Usefulness of cardiac hormones for evaluating valvular disease in cynomolgus monkeys (Macaca fascicularis)

Nonhuman primates are commonly used as experimental animals due to their biological resemblance to humans. In patients with cardiac disease, the levels of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) tend to increase in response to cardiac damage, and they are thus used as indicators for the diagnosis of human heart failure. However, no reference values for ANP and BNP have been reported for heart disease in nonhuman primates. In this study, we recorded the age, sex, and body weight of 202 cynomolgus monkeys, and performed evaluations to assess the ANP and BNP levels, electrocardiography and echocardiography, and accordingly divided the monkeys into two groups: healthy monkeys and those with spontaneous cardiac disease. Statistical analysis was performed to determine the relationship of ANP and BNP with the factors of age, sex, and body weight. No significant relationship was found between the levels of ANP and BNP and the factors of age, sex, and body weight. However, both the ANP and BNP levels were significantly different between the healthy monkeys and monkeys with valvular disease. Similar to humans, the ANP and BNP levels tended to increase with the progression of cardiac disease in monkeys. Based on these results, we concluded that ANP and BNP are indicators of cardiac disease in nonhuman primates, and that this nonhuman primate cardiac disease model is applicable for cardiology research in humans.

The Role of Extravalvular Cardiac Damage Staging in Aortic Valve Disease Management

Current management of patients with aortic valve disease, including aortic valve stenosis (AS), aortic valve regurgitation (AR), and mixed aortic valve disease (MAVD), remains challenging. American and European guideline recommendations regarding the timing of intervention are mainly based on the assessment of disease severity (ie, grading), presence of symptoms related to aortic valve disease, left ventricular systolic dysfunction, or LV enlargement. Furthermore, the decision regarding the type of intervention (ie, surgical vs transcatheter) is primarily based on risk assessment from surgical risk scores. There is, however, less emphasis on the importance of the assessment of anatomic and functional cardiac repercussions of aortic valve disease to guide the clinical management of these patients. Recently, a novel approach has been proposed to improve the management of aortic valve disease with 2 main components for risk stratification of the disease: 1) grading the severity of aortic valve disease, and 2) staging the extent of extravalvular cardiac damage associated with aortic valve disease with the use of echocardiography. To date, this novel approach of extravalvular cardiac damage staging was proposed and validated only in the context of AS but could be extended to other valvular heart diseases, including AR and MAVD. Further studies are also needed to test the incremental value of additional imaging parameters (eg, myocardial fibrosis by magnetic resonance) as well as blood biomarkers (eg, natriuretic peptide, cardiac troponin, and others) to the existing cardiac damage staging schemes.

Ventricular tachycardia in patients undergoing 24-h Holter monitoring as preoperative evaluation for noncardiac surgery

The incidence of ventricular tachycardia (VT) in preoperative evaluation for noncardiac surgery in general hospitals has not been established. The aim of this study was to determine the incidence of VT, characteristics of patients with VT, characteristics of VT, and significance of VT in patients undergoing 24-h Holter monitoring as preoperative evaluation for noncardiac surgery. In 601 patients, VT was detected in 46 patients (7.7%). In patients with VT, left ventricular ejection fraction (LVEF) was lower (62.6 ± 9.3% vs. 66.6 ± 8.9%, p = 0.003), and B-type natriuretic peptide (BNP) was higher compared with patients without VT (median, 52.5 pg/mL vs. 32.8 pg/mL, p = 0.02). The maximum number of consecutive beats of VT was more frequent in the patients with LVEF < 50% than in the patients with LVEF ≥ 50% (median, 11.5 beats vs. 3.0 beats, p = 0.01). Forty patients (87%) underwent scheduled surgery without major complications.

Possible diverse contribution of coronary risk factors to left ventricular systolic and diastolic cavity sizes

It is generally believed that risk factors damage the coronary arteries, cause myocardial ischemia, and consequently change the shape of the heart. On the other hand, each of the risk factors may also have a negative effect on the heart. However, it is very difficult to examine the effects of each of these risk factors independently. Therefore, it is necessary to select an appropriate statistical method and apply it efficiently. In this study, the effects of coronary risk factors on left ventricular size and cardiac function were investigated using structure equation modeling (SEM), and were shown as Bayesian SEM-based frequency polygons using selected two-dimensional contours. This study showed that each risk factor directly affected the shape of the heart. Because vascular risk and heart failure risk are likely to evolve at the same time, managing risk factors is very important in reducing the heart failure pandemic.

Evaluation of Enhanced Lipid Oxidation and Compensatory Suppression using Natriuretic Peptide in Patients with Cardiovascular Diseases

Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is recognized as a surrogate marker of lipid oxidation and is associated with arteriosclerosis. However, there are limited reports on the relationship between heart failure and MDA-LDL. Therefore, we aimed to determine whether MDA-LDL is activated in patients with left ventricular (LV) dysfunction and examine our hypothesis that the B-type natriuretic peptide (BNP) masks the enhancement of MDA-LDL in patients with LV dysfunction by its strong antioxidative action. The study population comprised 2,976 patients with various cardiovascular diseases. Patients were divided into four groups depending on the LV ejection fraction (LVEF) or plasma BNP level. A nonparametric analysis with the Kruskal-Wallis test was used to perform an interquartile comparison. In addition, structural equation modeling and Bayesian estimation were used to compare the effects of LVEF and BNP on MDA-LDL. MDA-LDL levels did not significantly change (P > 0.05) with respect to the degree of LVEF among the four groups. In contrast, MDA-LDL levels were significantly decreased (P < 0.001) with respect to the degree of BNP among the four groups. A path model based on structural equation modeling clearly showed a significant effect of LVEF (standardized regression coefficient; β: -0.107, P < 0.001) and BNP (β: -0.114, P < 0.001) on MDA-LDL, with a significant inverse association between LVEF and BNP (correlation coefficient -0.436, P < 0.001). MDA-LDL should be activated in patients with LV dysfunction; however, BNP is thought to exert a strong compensatory suppression on lipid oxidation, masking the relationship between heart failure and lipid oxidation.

Baseline NT-proBNP Accurately Predicts Symptom Response to Transcatheter Aortic Valve Implantation

Background

Up to 30% of patients undergoing transcatheter aortic valve implantation (TAVI) experience minimal symptomatic benefit or die within 1 year, indicating an urgent need for enhanced patient selection. Previous analyses of baseline NT‐proBNP (N‐terminal pro‐brain natriuretic peptide) and TAVI outcomes have assumed a linear relationship, yielding conflicting results. We reexamined the relationship between baseline NT‐proBNP and symptomatic improvement after TAVI.

Methods and Results

Symptom status, clinical and echocardiographic data, and baseline NT‐proBNP were reviewed from 144 consecutive patients undergoing TAVI for severe symptomatic aortic stenosis. The primary end point was change in New York Heart Association functional class at 1 year. There was a nonlinear, inverted‐U relationship between log‐baseline NT‐proBNP and post‐TAVI change in NYHA class (R²=0.4559). NT‐proBNP thresholds of <800 and >10 000 ng/L accurately predicted no symptomatic improvement at 1 year (sensitivity 88%, specificity 83%, positive predictive value 72%, negative predictive value 93%). In adjusted analyses, baseline NT‐proBNP outside this “sweet‐spot” range was the only factor independently associated with poor functional outcome (high: NT‐proBNP >10 000 ng/L, odds ratio [OR], 65; 95% CI, 6–664; low: NT‐proBNP <800 ng/L, OR, 73; 95% CI, 7–738).

Conclusions

Baseline NT‐proBNP is a useful prognostic marker to predict poor symptom relief after TAVI and may indicate when intervention is likely to be futile. Both low (<800 ng/L) and very high (>10 000 ng/L) levels are strongly associated with poor functional outcome, suggesting an alternative cause for symptoms in the former scenario and an irrevocably diseased left ventricle in the latter. Further evaluation of this relationship is warranted.

Therapeutic hypothermia after cardiac arrest increases the plasma level of B-type natriuretic peptide

Natriuretic peptides (NPs) regulate blood pressure and fluid homeostasis and exert various effects on the cardiovascular system. Recently, the relationship between NPs and the energy metabolism has been reported, and using a cell culture experiment system, we previously showed that NP activated brown cells in a low temperature environment while also suppressing a decrease in the cell temperature. However, few reports have described the secretion of NPs in cold environments, and there have been almost no studies of B-type natriuretic peptide (BNP) in humans. We investigated how NPs respond to cold environments in 21 patients who underwent therapeutic hypothermia (TH) after cardiac arrest. The plasma BNP levels were significantly increased (more than fivefold) during TH (logarithmically from 1.98 ± 0.79 to 2.63 ± 0.59, P < 0.01). During TH, diastolic pulmonary artery pressure (PAP) significantly decreased, and there were no significant changes in the stroke volume index (SVI). This increase of BNP was not associated with any hemodynamic changes. In contrast to our findings for BNP, the change in A-type NP (ANP) was quite small. We detected a significant increase in the plasma BNP levels during TH, unrelated to hemodynamics. This elevation of BNP levels seems to be potential influenced by hypothermia.

Low and elevated B-type natriuretic peptide levels are associated with increased mortality in patients with preserved ejection fraction undergoing transcatheter aortic valve replacement: an analysis of the PARTNER II trial and registry

Aims

B-type natriuretic peptide (BNP) is a cardiac neurohormone that is secreted in response to ventricular volume expansion and pressure overload. There are conflicting data regarding the association between BNP levels and outcomes after transcatheter aortic valve replacement (TAVR). We therefore sought to assess the association between baseline BNP and adverse outcomes in patients with symptomatic, severe aortic stenosis (AS), and left ventricular ejection fraction (LVEF) ≥50%, undergoing TAVR in the PARTNER 2 Trial and Registry.

Methods and results

A total of 1782 patients were included in the analysis, and BNP was evaluated both as a continuous log-transformed value and by a priori categories: low (&lt;50 pg/mL), normal (≥50 and &lt;100 pg/mL), moderately elevated (≥100 and &lt;400 pg/mL), or markedly elevated (≥400 pg/mL). Clinical outcomes from discharge to 2 years were compared between patients according to their baseline BNP level, using Kaplan–Meier event rates and multivariable Cox proportional hazards regression models. After adjustment, spline curves revealed a non-linear association between log-transformed BNP and all-cause and cardiovascular mortality in which both the lowest and highest values were associated with increased mortality. Two-year all-cause mortality rates for those with low (n = 86), normal (n = 202), moderately elevated (n = 885), and markedly elevated (n = 609) baseline BNP were 20.0%, 9.8%, 17.7%, and 26.1%, respectively. In adjusted models, compared to a normal baseline BNP, low [adjusted hazard ratio (HR) 2.6, 95% confidence interval (CI) 1.3–5.0, P-value 0.005], moderately elevated (adjusted HR 1.6, 95% CI 1.0–2.6, P-value 0.06), and markedly elevated (adjusted HR 2.1, 95% CI 1.3–3.5, P-value 0.003) BNP were associated with increased all-cause mortality, driven by cardiovascular mortality.

Conclusions

In a large cohort of patients with severe symptomatic AS and preserved LVEF undergoing TAVR, all-cause and cardiovascular mortality rates at 2 years were higher in patients with low and markedly elevated BNP levels.

Clinical Trial Registration

https://clinicaltrials.gov/ unique identifier #NCT01314313, #NCT02184442, #NCT03222128, and #NCT03222141.

Collaborative Activities of Noradrenaline and Natriuretic Peptide for Glucose Utilization in Patients with Acute Coronary Syndrome

Glucose is an important preferential substrate for energy metabolism during acute coronary syndrome (ACS) attack, although insulin resistance (IR) increases during ACS. Increasing evidence indicates that natriuretic peptides (NP) regulate glucose homeostasis. We investigated possible compensatory actions of NP in collaboration with other neurohumoral factors that facilitate glucose utilization during ACS. The study population consisted of 1072 consecutive cases with ischemic heart disease who underwent cardiac catheterization (ACS, n = 216; non-ACS, n = 856). Among ACS subjects, biochemical data after acute-phase treatment were available in 91 cases, defined as ACS-remission phase (ACS-rem). Path models based on covariance structure analyses were proposed to clarify the direct contribution of B-type NP (BNP) and noradrenaline to glucose and HOMA-IR levels while eliminating confounding biases. In non-ACS and ACS-rem subjects, although noradrenaline slightly increased glucose and/or HOMA-IR levels (P < 0.03), BNP did not significantly affect them. In contrast, in ACS subjects, high noradrenaline was a significant cause of increases in glucose and HOMA-IR levels (P < 0.001), whereas high BNP was a significant cause of decreases in both parameters (P < 0.005). These findings indicate that BNP and noradrenaline coordinately activate glucose metabolism during ACS, with noradrenaline increasing glucose levels, as an energy substrate, while BNP improves IR and promotes glucose utilization.