B-type natriuretic peptide and N-terminal pro B-type natriuretic peptide are depressed in obesity despite higher left ventricular end diastolic pressures

Blunted increase in plasma BNP during acute coronary syndrome attacks in obese patients

Background

Unexpectedly low natriuretic peptide (NP) levels in proportion to heart failure severity are often observed in obese individuals. However, the magnitude of NP elevation in response to acute cardiac stress in obesity has not yet been extensively studied. This study aimed to determine the impact of obesity on the increase in plasma NP in response to cardiac hemodynamic stress during acute coronary syndrome (ACS) attacks.

Methods and Results

The study population included 557 consecutive patients with ACS for whom data were collected during emergency cardiac catheterization. To determine the possible impact of body mass index (BMI) on the relationship between left ventricular ejection fraction (LVEF) and plasma B-type NP (BNP) levels, the study population was divided into two groups (Group 1: BMI <25, Group 2: BMI ≥25 [kg/m2]). Both BMI and LVEF were significantly and negatively correlated with BNP. Although a significant negative correlation between LVEF and BNP was observed in both groups, the regression line of Group 2 was significantly less steep than that of Group 1. Accordingly, BNP/LVEF ratio in Group 2, which indicates the extent of BNP increase in response to LVEF change, was significantly lower than that in Group 1.

Conclusions

Blunted increase in plasma BNP in response to cardiac hemodynamic stress during ACS attacks was observed in obese individuals. In addition to the relatively low plasma BNP levels at baseline in obese individuals, the blunted response of BNP elevation to ACS attacks may have important pathophysiological implications for hemodynamic regulation and myocardial energy metabolism.

Characteristics of heart failure with a preserved ejection fraction in black South African patients

Background

Heart failure with a preserved ejection fraction (HFpEF) is common in the elderly (≥75 years) and associated with arterial stiffness. The mean age of HFpEF presentation is lower (40-55 years) in sub-Saharan Africa. No clinical study has been conducted on HFpEF in identifying and characterising this phenotype at a younger age, moreover in a South African black population where the risk of HFpEF is two times higher than in other ethnic groups. This study investigated the characteristics of HFpEF in a black South African population, the biochemical markers that predict HFpEF and cardiac structural changes in this HF phenotype.

Methods

Sixty-six participants with HFpEF and 213 controls were enrolled. All participants gave informed consent and completed a standardised questionnaire. Echocardiographic, anthropometric, central haemodynamic measurements, pulse wave velocity (PWV) and biomarker analysis were done.

Results

The mean age of HFpEF participants was 54.88 ± 13.51 years. Most of the participants (76 %) were between 20 and 64 years, while only 24 % were older. HFpEF participants were hypertensive, and more obese with increased incidence of alcohol consumption. PWV was increased in HFpEF (9.97 ± 2.78 m/s) when compared to participants without HFpEF (6.11 ± 2.18 m/s), p < 0.0001. There were no significant associations between central haemodynamic parameters, N-terminal pro B-type natriuretic peptide (NT-proBNP) (p = 0.9746), and galectin-3 (p = 0.2166). NT-proBNP, but not galectin-3, was associated with left ventricular hypertrophy (p = 0.0002) and left atrial diameter (p = 0.0005).

Conclusion

HFpEF in South Africa is predominant in obese young to middle-age individuals with arterial stiffness and who consume alcohol regularly. NT-proBNP could be used to diagnose HFpEF, however, should be interpreted with caution in populations with a high prevalence of obesity.

Left Atrial Remodeling Related to Disproportionately Low B-Type Natriuretic Peptide in Acute Heart Failure Patients with Atrial Fibrillation

The diagnostic performance of B-type natriuretic peptide (BNP) for acute heart failure (HF) is impaired in patients with atrial fibrillation (AF). Increased AF burden in HF is associated with left atrial (LA) remodeling. Recent studies have revealed that LA remodeling may affect LV filling. We hypothesized that LA remodeling affects BNP secretion in acute HF conditions. The study investigated the clinical impact of LA remodeling on admission BNP levels in acute HF patients with and without AF. Consecutive acute HF hospitalized patients (n = 899) were divided into groups with (n = 382) or without AF (n = 507) and subdivided into disproportionately low BNP (LB) (≤200 pg/ml), medium BNP (200 to 600 pg/ml) and high BNP (≥600 pg/ml) subgroups. The AF group had a higher proportion of patients with LB than the non-AF group (23.6% vs 16.6%, p = 0.009). BNP levels in both groups were positively correlated with LV end-diastolic volume and negatively correlated with LV ejection fraction in both groups. In contrast, BNP was positively correlated with LA volume index in the non-AF group, but negatively correlated in the AF group. The survival rates were significantly higher in the LB group than in the other groups in non-AF. Conversely, there were no significant differences across all groups in AF patients. In conclusion, in patients with acute HF and AF, disproportionately low BNP levels are associated with LA structural remodeling and poor prognosis.

The Interplay between Adipose Tissue Properties and Levels of NT-proBNP in People with HIV

Objective

We aimed to assess the association between low N-terminal pro-brain natriuretic peptide (NT-proBNP) and body mass index (BMI), adipose tissue distribution, adiponectin, and HIV-specific risk factors among people with HIV (PWH).

Methods

We included 811 PWH with measurement of height, weight and waist circumference, blood samples analyzed for NT-proBNP, and visceral-(VAT) and subcutaneous (SAT) adipose tissue areas measured from CT-scans. Low concentrations of NT-proBNP were defined as concentrations below the limit of quantification (5.9 pmol/L). Associations were explored with multivariable logistic regression analyses adjusted for relevant confounders.

Results

We identified 471 (58%) individuals with low concentrations of NT-proBNP. Increasing BMI was associated with higher odds of low NT-proBNP (adjusted OR (aOR) 1.06 (95% CI: 1.01-1.11) per 1 kg/m2). Central obesity and large areas of VAT were associated with higher odds of low NT-proBNP (aOR 1.66 (1.16-2.36) and aOR 1.69 (1.09-2.62), respectively). Higher adiponectin was associated with lower odds of low NT-proBNP (aOR 0.86 (0.79-0.95) per 10% increase). No associations were found between low NT-proBNP and HIV-specific risk factors.

Conclusions

In PWH, low NT-proBNP is associated with an adverse adipose tissue profile with high BMI, central obesity, accumulation of VAT, and low adiponectin.

Association of N-terminal pro-B-type natriuretic peptide levels and mortality risk in acute myocardial infarction across body mass index categories: an observational cohort study

BACKGROUND

The prognostic value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) across body mass index (BMI) categories in patients with acute myocardial infarction (AMI) is unclear. We aimed to assess the predictive value of NT-proBNP levels and identify the best cutoff values for mortality risk prediction across BMI categories in AMI.

METHODS

We analyzed 4677 patients with AMI from the Cardiovascular Centre Beijing Friendship Hospital Database Bank. Patients were classified into underweight (< 18.5 kg/m2), normal-weight (18.5-23.9 kg/m2), overweight (24-27.9 kg/m2), and obese (≥ 28 kg/m2) groups. The association between NT-proBNP (ln-transformed) and mortality was investigated using Cox regression and stratified by BMI.

RESULTS

During follow-up (13,787 person-years of observation), 718 patients died, averaging 52.1 events per 1000 person-years. NT-proBNP levels were inversely correlated with BMI (β = - 0.096, P < 0.001). After adjustment, NT-proBNP was independently associated with all-cause mortality (hazard ratio [HR] per 1-SD: 1.82; 95% confidence interval [CI] 1.60-2.07) in patients with AMI. Similar findings were observed in analyses stratified by BMI category, except for the underweight group. Adding NT-proBNP to conventional risk models improved risk discrimination in normal-weight, overweight, and obese patients (C-index changes of 0.036, 0.042, and 0.032, respectively) and classification of patients into predicted mortality risk categories (net reclassification improvement 0.263, 0.204, and 0.197, respectively). The best NT-proBNP cutoff values for 5-year mortality risk prediction across BMI categories were 5710, 4492, 2253, and 1300 pg/ml.

CONCLUSION

NT-proBNP level was an independent prognostic factor for mortality in patients with AMI and varied according to BMI. The best NT-proBNP cutoff values for mortality risk prediction reduced as BMI increased.

Natriuretic Peptides as Predictors of Protein-Energy Wasting in Hemodialysis Population

OBJECTIVE

Imbalance between anabolism and catabolism is linked to cachexia and protein-energy wasting (PEW), especially in frail populations such as patients with chronic kidney disease. PEW is responsible of poor outcomes with increased morbidity and mortality. Several causes are involved in PEW such as insulin resistance, acidosis, or hyperparathyroidism. Natriuretic peptides (NPs) have recently been described as activators of resting energy expenditure through the induction of browning of white adipose tissue in rodents with chronic kidney disease. The present study was therefore implemented to investigate whether NPs could be associated with PEW criteria and predict clinical outcomes.

METHODS

We quantified serum N-terminal pro-B-type natriuretic peptide (NT-proBNP) in a prospective cohort of 231 patients undergoing maintenance hemodialysis and atrial natriuretic peptide in a subgroup of 35 patients. Body composition parameters were measured with bioimpedance spectroscopy.

RESULTS

NT-proBNP was inversely associated with serum albumin, prealbumin, and body mass index and, conversely, positively associated with age and C-reactive protein. NT-proBNP as well as atrial natriuretic peptide were significantly higher in patients with PEW criteria. NT-proBNP was negatively associated with body fat mass. In multiple linear regression, NT-proBNP remained associated with body mass index. Kaplan-Meier analysis revealed a significant correlation between serum NT-proBNP concentrations and all-cause mortality and cardiovascular events. This association remained significant after multivariable Cox regression models adjusted for demographic factors and cardiovascular risk factors.

CONCLUSION

Accumulation of NPs seems to be associated with poor nutritional status and reduced survival among hemodialysis patients. Further studies are needed to confirm this association using resting energy expenditure measurement and adipose tissue biopsy.

Effect of Obstructive Sleep Apnea and Positive Airway Pressure Therapy on Cardiac Remodeling as Assessed by Cardiac Biomarker and Magnetic Resonance Imaging in Nonobese and Obese Adults

It is unknown whether obesity modifies the effect of obstructive sleep apnea (OSA) and positive airway pressure (PAP) therapy on cardiac remodeling and NT-proBNP (N-terminal pro-B-type natriuretic peptide) levels. We compared NT-proBNP and cardiac magnetic resonance imaging in adults without OSA (n=56) and nonobese (n=73; body mass index <30 kg/m²) and obese (n=136; body mass index ≥30 kg/m²) adults with OSA. We also investigated these traits in nonobese (n=45) and obese (n=78) participants with OSA adherent to 4 months of PAP treatment. At baseline, left ventricular mass to end-diastolic volume ratio, a measure of left ventricular concentricity, was greater in both nonobese and obese participants with OSA compared with those without OSA. Participants with OSA and obesity exhibited reduced phasic right atrial function. No significant differences in baseline NT-proBNP were observed across groups. The effect of PAP treatment on NT-proBNP and left atrial volume index was significantly modified by obesity. In nonobese participants, PAP therapy was associated with a decrease in NT-proBNP (P<0.0001) without a change in left atrial volume index, whereas in obese participants, PAP was associated with an increase in left atrial volume index (P=0.006) without a change in NT-proBNP. OSA was associated with left ventricular concentric remodeling independent of obesity and right atrial dysfunction in participants who were obese. PAP treatment was associated with reduced NT-proBNP in nonobese participants with OSA, but left atrial enlargement in obese participants with OSA, suggesting that PAP-induced reduction in BNP release (which is known to occur during obstructive apnea episodes) may lead to volume retention in obese participants with OSA. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT01578031.

Plasma Clearance of B-Type Natriuretic Peptide (BNP) before and after Bariatric Surgery for Morbid Obesity

BACKGROUND

Obese patients have lower plasma concentrations of the cardiac natriuretic peptides (NPs) than their age- and sex-matched counterparts. This may reflect lower production and/or increased peptide clearance. It is unclear whether NP bioactivity is affected by obesity.

METHODS

We studied the effects of obesity on B-type natriuretic peptide (BNP) clearance and bioactivity by comparing results from standardized intravenous infusions of BNP administered 2 weeks before and 6 months after bariatric surgery in 12 consecutive patients with morbid obesity (body mass index, BMI > 35 kg/m2). Anthropometric, clinical, neurohormonal, renal, and echocardiographic variables were obtained pre- and postsurgery. Pre- vs postsurgery calculated intrainfusion peptide clearances were compared.

RESULTS

BMI (44.3 ± 5.0 vs 33.9 ± 5.2 kg/m2, P < 0.001) and waist circumference (130.3 ± 11.9 vs 107.5 ± 14.7 cm, P < 0.001) decreased substantially after bariatric surgery. Calculated plasma clearance of BNP was reduced (approximately 30%) after surgery. Though not controlled for, sodium intake was presumably lower after bariatric surgery. Despite this, preinfusion endogenous plasma NP concentrations did not significantly differ between pre- and postsurgery studies. The ratio of plasma N-terminal (NT)-proBNP to 24 h urine sodium excretion was higher postsurgery (P = 0.046; with similar nonsignificant findings for BNP, atrial NP (ANP) and NT-proANP), indicating increased circulating NPs for a given sodium status. Mean plasma NP concentrations for given calculated end-systolic wall stress and cardiac filling pressures (as assessed by echocardiographic E/e') rose slightly, but not significantly postsurgery. Second messenger, hemodynamic, renal, and neurohormonal responses to BNP were not altered between studies.

CONCLUSION

Obesity is associated with increased clearance, but preserved bioactivity, of BNP.

The relationship between body mass index and N-terminal pro-B-type natriuretic peptide in community-acquired pneumonia

BACKGROUND

The relationship between body mass index (BMI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) has not been fully investigated in patients with community-acquired pneumonia (CAP).

METHODS

This prospective observational study examined 510 consecutive patients hospitalized for CAP. NT-proBNP, BMI, and the pneumonia severity index (PSI) were determined for all participants. The moderating effects of BMI on the relationship between NT-proBNP and CAP mortality were examined using interaction terms in a multivariable regression model. The ability of NT-proBNP to predict mortality was evaluated using the area under the curve (AUC).

RESULTS

A significant inverse relationship was observed between BMI and NT-proBNP. After multivariable adjustment including BMI, NT-proBNP remained a significant predictor of CAP mortality. The AUC of the fully adjusted (including BMI) NT-proBNP model was significantly higher than that excluding BMI (p = 0.021) and that of PSI (p = 0.038), respectively. The predictive performance of NT-proBNP for mortality significantly differed by BMI group, with the NT-proBNP of the overweight and obesity group having a significantly higher AUC than that of the underweight and normal-weight group. The AUC of NT-proBNP was significantly higher and tended to be higher than that of PSI in the overweight group (p = 0.013) and the obesity group (p = 0.113), respectively.

CONCLUSIONS

BMI significantly strengthens the prognostic performance of NT-proBNP in CAP patients. The BMI-NT-proBNP interaction is significantly associated with CAP mortality, but as a prognostic determinant for CAP, NT-proBNP seems to be more useful for overweight and obese patients than for underweight and normal-weight patients.

N-Terminal pro-B-type natriuretic peptide and coronary microvascular dysfunction in women with preserved ejection fraction: A report from the Women's Ischemia Syndrome Evaluation-Coronary Vascular Dysfunction (WISE-CVD) study

BACKGROUND

Women with symptoms and signs of ischemia, preserved left ventricular ejection fraction (LVEF), and no obstructive coronary artery disease (CAD), often have coronary microvascular dysfunction (CMD), and are at risk of future heart failure with preserved ejection fraction (HFpEF). N-terminal pro-B-type natriuretic peptide (NT-proBNP) is used to evaluate HF and myocardial ischemia. Relationships between NT-proBNP and CMD are not well defined in this population.

METHODS

We evaluated resting NT-proBNP levels in 208 women with symptoms and signs of ischemic heart disease, preserved LVEF and no obstructive CAD undergoing clinically indicated invasive coronary flow reserve (CFR) as a measure of CMD-related ischemia and resting left ventricular end-diastolic pressure (LVEDP). Chi-square testing was used for categorical variables and ANOVA or Kruskal-Wallis tests were used for continuous variables.

RESULTS

Overall, 79% had an elevated resting LVEDP, and mean NT-proBNP was 115 ± 158 pg/mL. NT-proBNP levels correlated directly with age (r = 0.28, p = <0.0001), and indirectly with body mass index (r = -0.21, p = 0.0006), but did not independently associate with CFR. When stratified by NT-proBNP thresholds, higher NT-proBNP was initially associated with lower CFR, which did not persist with adjustment for multiple testing (p = 0.01 and 0.36, respectively).

CONCLUSION

Among women with symptoms and signs of ischemia, preserved LVEF, no obstructive CAD, and undergoing clinically indicated functional coronary angiography (FCA) for suspected CMD, while a majority had elevated resting LVEDP, we failed to find an independent association between CFR and NT-proBNP, although stratified clinical thresholds may relate to lower CFR. Further work is needed to investigate if these findings support the hypothesis that CMD-related ischemia may be a precursor to HFpEF.

Disproportionately low BNP levels in patients of acute heart failure with preserved vs. reduced ejection fraction

BACKGROUND

B-type natriuretic peptide (BNP) has been widely used for the diagnosis of heart failure, its severity, and prognosis. However, little is known about factors related to disproportionately low BNP levels even during acute heart failure conditions.

METHODS AND RESULTS

Among 424 patients hospitalized for acute heart failure, we categorized the patients into the HFpEF (LVEF > 50%) or HFrEF (LVEF ≤ 50%) group and subdivided them into disproportionately low BNP (LB) group and high BNP (HB) group using a cut-off BNP level of 200 pg/mL at admission. The proportion of patients with LB was higher in the HFpEF group (22.2%) than in the HFrEF group (10.9%, p = 0.002). Patients with LB had a high BMI, lower blood pressure, and history of previous cardiovascular surgery in the HFpEF group, while patients in the HFrEF group had a high BMI and smaller left ventricular end-diastolic volume index. Furthermore, presence of LB in the HFrEF group was related to good prognosis, but LB in the HFpEF group was an indicator of poor prognosis as HB group.

CONCLUSIONS

The factors associated with LB were different between the HFpEF and HFrEF groups. LB was related to good prognosis in HFrEF, but not in HFpEF.

Serum B-type natriuretic peptide does not increase with higher systolic blood pressure in obese men despite evidence of blood pressure-related increases in left ventricular mass and filling pressure

B-type natriuretic peptide (BNP) is a cardiac hormone secreted predominantly from the ventricles in response to increased ventricular pressure. Along this line, hypertensive patients with left ventricular hypertrophy typically have high circulating BNP concentrations. BNP has natriuretic and vasodilatory actions. Obese persons have low circulating BNP concentrations, and a relative lack of this natriuretic and vasodilatory factor could contribute to obesity-related hypertension. The relationship between BNP, BP, left ventricular mass (LVM), and left ventricular filling pressure among obese persons is not clear. To address this issue, we studied 98 healthy obese medication-free men with normal left ventricular ejection fraction. We measured BP using 24 -h ambulatory (A) BP recordings, LVM and E/e', an estimate of left ventricular filling pressure, using echocardiography, and fasting BNP in serum. Mean systolic ABP ± SD was 114 ± 4 mm Hg in 1^st and 149 ± 8 mm Hg in 4^th systolic ABP quartile, P < 0.001. LVM and E/e' increased across systolic ABP quartiles (mean LVM±SD: 81.5±13.7 g/m² in 1^st and 100.1 ± 26.7 g/m² in 4^th quartile, P = 0.018; mean E/e'±SD: 5.3±1.6 in 1^st and 7.0 ± 2.0 in 4^th quartile, P = 0.002). In contrast, serum BNP did not increase across systolic ABP quartiles (median (IQR): 6.7 (3.1-12.3) pg/ml in 1^st and 5.3 (2.8-9.7) pg/ml in 4^th quartile, P = 0.75). Unexpectedly, among healthy obese medication-free men, serum BNP does not increase with higher systolic ABP despite evidence of BP-related increases in LVM and E/e'. This further suggests that a relatively low amount of circulating BNP could contribute to obesity-related hypertension in its early stages.

Diagnostic and prognostic considerations for use of natriuretic peptides in obese patients with heart failure

Natriuretic peptides (NPs, B-type natriuretic peptide /BNP and NT-proBNP) are universally used biomarkers with established cut-points to aid in the diagnosis of heart failure (HF). It has been demonstrated that an inverse relationship exists between obesity, defined by the body mass index (BMI), and NPs, such that the application of NPs to diagnostic algorithms in HF remains challenging in overweight and obese patients. Some have advocated that lowering the cut-offs for NPs or using a correction for high BMI may improve the diagnostic accuracy in obese individuals. The inverse relationship of NPs with high BMI is present in both HF with reduced (HFrEF) and with preserved (HFpEF) ejection fraction, although levels tend to be higher in HFrEF. Nevertheless, data from several studies have shown that the prognostic value of NPs is preserved across BMI classes, and that increasing circulating levels of NPs correlate with adverse outcomes including all-cause mortality and HF hospitalizations. While NPs can still be used in diagnosis of HF in obese individuals, lower thresholds and the clinical context should be utilized in decision making. Additionally, given the validated prognostic value even in obesity, NPs can be employed in risk-stratification of individuals with obesity and HF, although there remains limited evidence about use in those with severe obesity (BMI >40 kg/m²).

The health outcomes of inflammation and obesity in patients with heart failure

BACKGROUND

Although obesity is a risk factor for cardiovascular disease, higher body mass index is related to longer event-free survival in patients with heart failure (HF). While previous research demonstrated that higher levels of inflammatory mediators were associated with shorter event-free survival, the effect of inflammation on the association between obesity and outcomes of HF have not been considered.

HYPOTHESIS

Based on the obesity paradox, we hypothesized that patients with higher baseline body mass index (BMI) would experience better event-free survival than those with lower BMI regardless of inflammatory status.

METHOD

A sample of 415 patients with HF (age 61 ± 11.5 years; 31% female) provided blood to measure soluble tumor necrosis factor receptor1 (sTNFR1), a biomarker of inflammation. Patients were divided into 4 groups based on BMI and a median split of sTNFR1 levels: (1) high BMI ≥ 30 and sTNFR1 > 1804 pg/ml, (2) high BMI ≥ 30 and low sTNFR1 ≤ 1804 pg/ml, and (3) low BMI < 30 and high sTNFR1 > 1804 pg/ml vs. (4) low BMI < 30 and sTNFR1 ≤ 1804 pg/ml. Patients were followed for an average of 365 days to determine the time to first event of either all-cause hospitalization or death.

RESULTS

There were 177 patients (43%) who experienced either an all-cause hospitalization or death. In a Cox regression, high BMI and high sTNFR1 category predicted time to event (hazard ratio = 1.7, 95% confidence interval = 1.01-2.9) with age, gender, race, left ventricular ejection fraction, New York Heart Association functional class (I/II versus III/IV), log-transformed N-terminal Pro-B-type natriuretic peptide levels, prescribed statin (yes/no), and comorbidity as covariates.

CONCLUSION

Being in a higher inflammation group was associated with shorter event-free survival regardless of BMI. This study provides evidence that inflammation is an important consideration in the association between obesity and better outcomes in patients with HF.

The Effects of Salt and Glucose Intake on Angiotensin II and Aldosterone in Obese and Nonobese Patients with Essential Hypertension

Background

The exact mechanisms for the development of essential hypertension are not known. Activation of the renin-angiotensin-aldosterone system (RAAS) in adipose tissue may represent an important link between obesity and hypertension. This study investigates the effects of oral intake of glucose with and without NaCl on angiotensin II (AngII) and aldosterone in obese and nonobese patients with essential hypertension.

Methods

Twenty newly diagnosed untreated essential hypertensive patients and 15 normotensive control subjects matched for age, gender, and BMI were studied. Participants fasted overnight (8–10 hrs), and then each subject took 75 gm glucose alone and with 3 gm NaCl, each dissolved in 250 ml. Subjects were monitored for 2 hours. Half hourly BP, plasma glucose (PG), serum Na⁺, K⁺, insulin, AngII, and aldosterone were measured. Subjects were classified into obese (BMI >30 Kg/m²) (11 patients and 8 control) and nonobese (BMI <30 Kg/m²) (9 patients and 7 control).

Results

After intake of glucose with NaCl serum, AngII was significantly higher in obese hypertensive patients compared with nonobese patients (P = 0.016). Intake of glucose with NaCl resulted in a significantly higher serum Na in obese hypertensive patients compared with nonobese patients Na (P = 0.009). Serum aldosterone was significantly higher in obese patients (P = 0.03, after glucose; P = 0.003, after glucose with NaCl) and in nonobese patients (P = 0.000 and P = 0.000, respectively) compared with their respective normotensive control subjects. In obese and nonobese patients, intake of glucose and glucose with NaCl showed no significant change in the levels of serum AngII and aldosterone which was associated a significant increase in serum Na in obese patients (P = 0.03) and a highly significant reduction in serum K in nonobese patients (P = 0.001).

Conclusion

Failure of suppression or inappropriate maintenance of secretion of AngII and aldosterone in both hypertensive groups by intake of glucose with NaCl may indicate a possible mechanism of essential hypertension.

Prognostic characteristics and body mass index in patients with pulmonary embolism: does size matter?

Objective

The aim of this study was to explore the impact of body mass index (BMI) on prognostic indicators and clinical outcomes in patients with pulmonary embolism.

Methods

Patients with pulmonary embolism from the Hokusai venous thromboembolism (VTE) randomised clinical trial that compared two anticoagulant regimens were followed-up for 1 year (n=1911). Patients were analysed with regard to World Health Organization (WHO) BMI categories at baseline (underweight (<18.5), normal (18.5 to <25), overweight (25 to <30), obese I (30 to <35), obese II (35 to <40), and obese III (≥40)). Clinical and radiological prognostic characteristics for right ventricular dysfunction and adverse events were assessed with normal weight as a reference. Clinical outcomes were mortality, recurrent VTE, hospitalisation, bleeding and overall adverse events.

Results

The relationship between BMI categories and both prognostic parameters and clinical outcomes showed U-shaped curves. Adjusted odds ratios (aORs) were highest in patients who were grade III obese for both clinical parameters (N-terminal pro-brain natriuretic peptide (NT-proBNP) >600 and simplified pulmonary embolism severity index (sPESI)≥1; 2.9 and 1.6), and radiological parameters (pulmonary trunk>29 mm, right-to-left-ventricular ratio>1.0, and central emboli; aOR=4.3, 2.1 and 2.3). Bleeding was observed more frequently in the higher categories of obesity. In patients who were underweight, for NT-proBNP>600 and sPESI≥1 the aORs were 2.6 and 2.5, respectively; however, no major bleeding occurred in this category.

Conclusion

Several clinical and radiological prognostics characteristics and right ventricular dysfunction in pulmonary embolism are not evenly distributed among BMI categories. This is reflected in a trend towards worse outcomes in patients who are overweight and underweight.

Overweight patients with pulmonary embolism have a higher risk of heart dysfunction and worse outcomeshttp://bit.ly/2Pwtln0

Biomarkers of Atrial Fibrillation in Metabolic Syndrome

Whether the increased atrial fibrillation (AF) risk in metabolic syndrome (MetS) patients is due to the syndrome as a whole or simply the sum of the risks of its individual component parts is still obscure. These two clinical entities share many pathophysiological links and thus distinction between a casual observation and a significant association is difficult. Biomarkers associated with pathogenesis of AF in the context of MetS have the ability to refine future risk prediction. In the present review we identify circulating substances that could be regarded as potential biomarkers for prediction of incident AF, or of cardiovascular events in the setting of AF in patients with MetS. Cardiac myocyte injury and stress markers (troponin and natriuretic peptides), markers of renal function (glomeral filtration rate, cystatin-C), and inflammation markers/mediators (interleukin- 6, CRP) are promising biomarkers of patients with AF and MetS.

Prognostic Value of Time Interval Between Mitral and Tricuspid Valve Opening in Patients With Heart Failure

BACKGROUND

We used dual Doppler echocardiography to measure the time interval between the mitral and tricuspid valve opening (MO-TO time), which we expected would reflect the balance between left and right ventricular hemodynamics. Methods and Results: We prospectively enrolled 60 patients with heart failure (HF) and sinus rhythm. The MO-TO time was measured in addition to routine echocardiography parameters, invasive hemodynamic parameters and plasma B-type natriuretic peptide (BNP) level in all patients. Patients were divided into 2 groups based on the MO-TO time: MOP (mitral opening preceding tricuspid opening), and TOP (tricuspid opening preceding mitral opening) groups. We followed up the predefined adverse outcomes (cardiovascular [CV] death and hospitalization due to worsening HF) for 1 year. Pulmonary artery wedge pressure (PAWP) and mean pulmonary artery pressure (mPAP) were higher in the MOP than in the TOP group (P<0.001; P<0.001, respectively). The probability of an adverse CV outcome was higher in the MOP than in the TOP group (log-rank test; P=0.002). Addition of MOP improved the predictive power of univariate predictors (mitral E/A ratio and BNP) in the bivariate Cox analysis (P=0.017, P=0.024, respectively).

CONCLUSIONS

MOP reflects pulmonary hypertension caused by left heart disease and has prognostic value in predicting adverse CV events in patients with HF.

The conundrum of patients with obesity, exercise intolerance, elevated ventricular filling pressures and a measured ejection fraction in the normal range

Patients with obesity, a reduced exercise capacity, increased cardiac filling pressures and a measured left ventricular ejection fraction in the normal range do not have a homogeneous disorder, but instead, exhibit one of three phenotypes. First, many obese people exhibit sodium retention, plasma volume expansion and cardiac enlargement, and some are likely to have heart failure that is related to hypervolaemia, even though cardiac index and circulating levels of natriuretic peptides are not meaningfully increased. Second, in some middle-aged men and women (particularly those with minimal co-morbidities), levels of natriuretic peptides increase markedly and can lower systemic vascular resistance, thus leading to high-output heart failure (HOHF) and glomerular hyperfiltration. Third, older obese people, particularly women with multiple co-morbidities, exhibit the syndrome of heart failure with a preserved ejection fraction (HFpEF). Despite degrees of plasma volume expansion similar to HOHF, these patients exhibit only modestly increased ventricular dimensions and circulating levels of natriuretic peptides (despite a high prevalence of atrial fibrillation), and glomerular function is characteristically impaired. A conceptual framework is proposed to distinguish among the three phenotypes seen in obese patients with exercise intolerance, increased ventricular filling pressures and a measured left ventricular ejection fraction in the normal range, since they may respond differently to therapeutic interventions. Efforts are needed to enhance the recognition of heart failure in obese people and to ensure that clinical trials that are designed to study patients with HFpEF actually enrol those who have the disease.

Natriuretic peptides promote glucose uptake in a cGMP-dependent manner in human adipocytes

Robust associations between low plasma level of natriuretic peptides (NP) and increased risk of type 2 diabetes (T2D) have been recently reported in humans. Adipose tissue (AT) is a known target of NP. However it is unknown whether NP signalling in human AT relates to insulin sensitivity and modulates glucose metabolism. We here show in two European cohorts that the NP receptor guanylyl cyclase-A (GC-A) expression in subcutaneous AT was down-regulated as a function of obesity grade while adipose NP clearance receptor (NPRC) was up-regulated. Adipose GC-A mRNA level was down-regulated in prediabetes and T2D, and negatively correlated with HOMA-IR and fasting blood glucose. We show for the first time that NP promote glucose uptake in a dose-dependent manner. This effect is reduced in adipocytes of obese individuals. NP activate mammalian target of rapamycin complex 1/2 (mTORC1/2) and Akt signalling. These effects were totally abrogated by inhibition of cGMP-dependent protein kinase and mTORC1/2 by rapamycin. We further show that NP treatment favoured glucose oxidation and de novo lipogenesis independently of significant gene regulation. Collectively, our data support a role for NP in blood glucose control and insulin sensitivity by increasing glucose uptake in human adipocytes. This effect is partly blunted in obesity.

Obesity and heart failure with preserved ejection fraction: A growing problem

Heart Failure with Preserved Ejection Fraction (HFpEF) is increasing in prevalence due to the aging of the United States population as well as the current obesity epidemic. While obesity is very common in patients with HFpEF, obesity may represent a specific phenotype of HFpEF characterized by unique hemodynamics and structural abnormalities. Obesity induces a systemic inflammatory response that may contribute to myocardial fibrosis and endothelial dysfunction. The most obese patients continue to be excluded from HFpEF clinical trials, and thus ongoing research is needed to determine the role of pharmacologic and interventional approaches in this growing population.

Natriuretic peptides in the control of lipid metabolism and insulin sensitivity

Natriuretic peptides have long been known for their cardiovascular function. However, a growing body of evidence emphasizes the role of natriuretic peptides in human substrate and energy metabolism, thereby connecting the heart with several insulin-sensitive organs like adipose tissue, skeletal muscle and liver. Obesity may be associated with an impaired regulation of the natriuretic peptide system, also indicated as a natriuretic handicap. Evidence points towards a contribution of this natriuretic handicap to the development of obesity, type 2 diabetes mellitus and cardiometabolic complications, although the causal relationship is not fully understood. Nevertheless, targeting the natriuretic peptide pathway may improve metabolic health in obesity and type 2 diabetes mellitus. This review will focus on current literature regarding the metabolic roles of natriuretic peptides with emphasis on lipid metabolism and insulin sensitivity. Furthermore, it will be discussed how exercise and lifestyle intervention may modulate the natriuretic peptide-related metabolic effects.

Joint statement of the European Association for the Study of Obesity and the European Society of Hypertension: obesity and heart failure

Obese individuals are more likely to develop heart failure. Yet, once heart failure is established, the impact of overweight and obesity on prognosis and survival is unclear. The purpose of this joint scientific statement of the European Association for the Study of Obesity and the European Society of Hypertension is to provide an overview on the current scientific literature on obesity and heart failure in terms of prognosis, mechanisms, and clinical management implications. Moreover, the document identifies open questions that ought to be addressed. The need for more tailored weight management recommendations in heart failure will be emphasized and, in line with the emerging evidence, aims to distinguish between primary disease and secondary outcome prevention. In the primary prevention of heart failure, it appears prudent advising obese individuals to lose or achieve a healthy body weight, especially in those with risk factors such as hypertension or type 2 diabetes. However, there is no evidence from clinical trials to guide weight management in overweight or obese patients with established heart failure. Prospective clinical trials are strongly encouraged.

NT-proBNP, Cardiometabolic Risk Factors, and Nutritional Status in Hemodialysis Patients

Background

We aimed to evaluate the association between NT-proBNP and malnutrition in HD patients while taking into account the four established categories of parameters for diagnosis of protein energy wasting (PEW).

Methods

A cross-sectional study was performed in Afro-Caribbean dialysis patients. One component in each of the 4 categories for the wasting syndrome was retained: serum albumin ≤ 38 g/L, BMI ≤ 23 Kg/m², serum creatinine ≤ 818 µmol/L, and normalized protein catabolic rate (nPCR) ≤ 0.8 g/kg/day. NT-proBNP was assessed using a chemiluminescence immunoassay. Two multivariate logistic regression models were performed to determine the parameters associated with high NT-proBNP concentrations.

Results

In 207 HD patients, 16.9% had PEW (at least three components). LVEF lower than 60% was found in 13.8% of patients. NT-proBNP levels ranged from 125 to 33144 pg/mL. In model 1, high levels of NT-proBNP (≥6243 pg/mL) were independently associated with PEW OR 14.2 (3.25–62.4), male gender 2.80 (1.22–6.57), hsCRP > 5 mg/L 3.90 (1.77–8.57), and dialysis vintage > 3 years 3.84 (1.35–10.8). In model 2, LVEF OR was 0.93 (0.88–0.98). NT-proBNP concentrations were significantly higher when the PEW component number was higher.

Conclusion

In dialysis patients, high NT-proBNP levels must draw attention to cardiac function but also to nutritional status.

Rationales and choices for the treatment of patients with NYHA class II heart failure

Heart failure (HF) in the United States represents a significant burden for patients and a tremendous strain on the healthcare system. Patients receiving a diagnosis of HF can be placed into 1 of 4 New York Heart Association (NYHA) functional classifications; the greatest proportion of patients are in the NYHA class II category, which is defined as patients having a slight limitation of physical activity but who are comfortable at rest, and for whom ordinary physical activity results in symptoms of HF. Because the severity of NYHA class II HF may be perceived as mild or unalarming by this definition, the urgency to treat this type of HF may be overlooked. However, these patients are optimal candidates for active intervention because their HF is at a critical point on the disease progression continuum when untoward changes can be halted or reversed. This review discusses the physiological consequences of NYHA class II HF with reduced ejection fraction and describes recent clinical trials that have demonstrated a therapeutic benefit for patients in this population. In doing so, we hope to establish that patients with NYHA class II disease merit careful attention and to provide reassurance to the treating community that options are available for these patients.

The effects of exercise training and caloric restriction on the cardiac oxytocin natriuretic peptide system in the diabetic mouse

BACKGROUND

Regular exercise training (ET) and caloric restriction (CR) are the frontline strategies in the treatment of type 2 diabetes mellitus with the aim at reducing cardiometabolic risk. ET and CR improve body weight and glycemic control, and experimental studies indicate that these paradigms afford cardioprotection. In this study, the effects of combined ET and CR on the cardioprotective oxytocin (OT)-natriuretic peptide (NP) system were determined in the db/db mouse, a model of type 2 diabetes associated with insulin resistance, hyperglycemia, and obesity.

METHODS

Five-week-old male db/db mice were assigned to the following groups: sedentary, ET, and ET + CR. Nonobese heterozygote littermates served as controls. ET was performed on a treadmill at moderate intensity, and CR was induced by reducing food intake by 30% of that consumed by sedentary db/db mice for a period of 8 weeks.

RESULTS

After 8 weeks, only ET + CR, but not ET, slightly improved body weight compared to sedentary db/db mice. Regardless of the treatment, db/db mice remained hyperglycemic. Hearts from db/db mice demonstrated reduced expression of genes linked to the cardiac OT-NP system. In fact, compared to control mice, mRNA expression of GATA binding protein 4 (GATA4), OT receptor, OT, brain NP, NP receptor type C, and endothelial nitric oxide synthase (eNOS) was decreased in hearts from sedentary db/db mice. Both ET alone and ET + CR increased the mRNA expression of GATA4 compared to sedentary db/db mice. Only ET combined with CR produced increased eNOS mRNA and protein expression.

CONCLUSION

Our data indicate that enhancement of eNOS by combined ET and CR may improve coronary endothelial vasodilator dysfunction in type 2 diabetes but did not prevent the downregulation of cardiac expression in the OT-NP system, possibly resulting from the sustained hyperglycemia and obesity in diabetic mice.

The influence of body composition on the N-terminal pro-B-type natriuretic peptide level and its prognostic performance in patients with acute coronary syndrome: a cohort study

BACKGROUND

Whether body composition is associated with the N-terminal pro-B-type natriuretic peptide (NT-proBNP) level and its prognostic performance in acute coronary syndrome (ACS) remains unknown. We aimed to investigate the influence of body composition on the NT-proBNP level and its prognostic performance among ACS patients.

METHODS

In total, 1623 ACS patients with NT-proBNP data were enrolled. Percent body fat and lean mass index were estimated using the Clínica Universidad de Navarra-Body Adiposity Estimator equation. Patients were divided into three groups according to the tertiles of sex-specific body mass index, percent body fat, or lean mass index. The endpoints were death from any cause and cardiovascular death.

RESULTS

Body mass index was inversely correlated with NT-proBNP levels (β = -0.036, P = 0.003). Lean mass index, but not percent body fat, was inversely associated with NT-proBNP levels (β of lean mass index = -0.692, P = 0.002). During a median follow-up of 23 months, 161 all-cause deaths occurred, and of these, 93 (57.8 %) were attributed to cardiovascular causes. Multivariate Cox analysis showed that the NT-proBNP level independently predicted all-cause mortality or cardiovascular death in the lower body mass index, lean mass index, and percent body fat groups. However, the prognostic performance of NT-proBNP was attenuated in patients with high body mass index, lean mass index, and percent body fat. In the subgroup of patients with diabetes, inverse associations between NT-proBNP levels and body mass index or body composition were not observed. In addition, the negative influence of high body mass index and body composition on the prognostic performance of the NT-proBNP level appeared to be attenuated.

CONCLUSIONS

Body mass index and lean mass index, but not percent body fat, are inversely associated with NT-proBNP levels. The prognostic performance of this biomarker may be compromised in patients with high body mass index, percent body fat, or lean mass index. Additionally, the influence of body composition on the NT-proBNP level and its prognostic performance might be attenuated in diabetic patients with ACS.

N-Terminal Pro-Brain Natriuretic Peptide and Heart Failure Risk Among Individuals With and Without Obesity: The Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Obesity is a risk factor for heart failure (HF) but is associated with lower N-terminal pro-brain natriuretic peptide (NT-proBNP) levels. It is unclear whether the prognostic value and implications of NT-proBNP levels for HF risk differ across body mass index (BMI) categories.

METHODS AND RESULTS

We followed up 12 230 ARIC participants free of prior HF at baseline (visit 2, 1990-1992) with BMI ≥18.5 kg/m(2). We quantified and compared the relative and absolute risk associations of NT-proBNP with incident HF across BMI categories. There were 1861 HF events during a median 20.6 years of follow-up. Despite increased HF risk in obesity, a weak inverse association was seen between baseline BMI and NT-proBNP levels (r=-0.10). Nevertheless, higher baseline NT-proBNP was associated with increased HF risk in all BMI categories. NT-proBNP improved HF risk prediction overall, even among those with severe obesity (BMI ≥35 kg/m(2); improvement in C statistic, 0.032; 95% confidence interval, 0.011-0.053). However, given the higher HF rates among those with obesity, at each NT-proBNP level, higher BMI was associated with greater absolute HF risk. Indeed, among those with NT-proBNP of 100 to <200 pg/mL, the average 10-year HF risk was <5% among normal-weight individuals but >10% among the severely obese.

CONCLUSIONS

Despite its inverse relationship with BMI, NT-proBNP provides significant prognostic information on the risk of developing HF even among individuals with obesity. Given the higher baseline HF risk among persons with obesity, even slight elevations in NT-proBNP may have implications for increased absolute HF risk in this population.

Adiponectin is independently associated with NT-proBNP: The Multi-Ethnic Study of Atherosclerosis

BACKGROUND AND AIMS

To investigate the associations between selected adipokines and the N-terminal prohormone of B-type natriuretic peptide (NT-proBNP).

METHODS AND RESULTS

As many as 1489 individuals enrolled in the Multi-Ethnic Study of Atherosclerosis were evaluated at 4 clinic visits about every 2 years. The evaluation included fasting venous blood, which was analyzed for NT-proBNP (at visits 1 and 3) and the adipokines adiponectin and leptin (at visits 2 and 3). The mean age was 64.8 ± 9.6 years and 48% were female. After multivariable adjustment, a 1-SD increment in adiponectin was associated with a 14 pg/ml higher NT-proBNP level (p < 0.01), while, compared to the 1st quartile of adiponectin, the 2nd, 3rd and 4th quartiles had 28, 45 and 67% higher NT-proBNP levels (p < 0.01 for all). For changes in NT-proBNP over the follow-up period, and after multivariable adjustment including baseline NT-proBNP, a 1-SD increment in adiponectin was associated with a 25 pg/ml absolute increase in NT-proBNP (p < 0.01), while those in the 2nd, 3rd and 4th quartiles of adiponectin were associated with increases of 5, 28 and 65 pg/ml (p = 0.74, 0.09 and <0.01, respectively). There was a significant interaction between adiponectin and sex for visit 3 NT-proBNP (p-interaction < 0.01), with significantly stronger associations in men. Leptin was not associated with NT-proBNP.

CONCLUSION

Higher adiponectin, but not leptin, is significantly associated with higher levels of NT-proBNP, as well as with greater longitudinal increases in NT-proBNP. The associations were stronger in men.

Fluctuations of the anthropometric indices and mortality of patients with incident heart failure: a prospective study in the community

BACKGROUND

The relationship between the fluctuations of the anthropometric indices (AIs) and the prognosis of patients with incident heart failure (HF) in a population-based cohort is unknown.

AIMS

To assess the relationship between the fluctuations of the AIs, body mass index (BMI), waist hip ratio (WHR), and weight height ratio (WHeR) and the prognosis of patients with incident HF.

METHODS

Anthropometric indices were prospectively measured in a 10-year population-based study of 6492 patients with incident HF (GAMIC cohort). 4530 patients (66.7%) died, during a mean follow-up of 72.7 ± 14.2 months. A time-updated analysis of the changes of the AIs was performed to assess their association with mortality and morbidity (hospitalisations and visits).

RESULTS

Patients with incident HF presenting ≥ 5% decrease or ≥ 7% increase of the AIs have an increased mortality [HR ≥ 1.65 (1.52-2.34) or HR ≥ 1.71 (1.58-1.85), respectively, p < 0.001]. Mortality risk increased ≥ 1.43-fold (p = -0.0003) for each 10% change in the AIs. There was an accelerated pattern of reduction in the AIs in the 6 months prior to death, and an accelerated increase in the AIs in the 3 months prior to hospitalisation. These observations were independent of the aetiology (ischaemic vs. non-ischaemic), the type of HF (systolic vs. non-systolic), and other predictors of mortality.

CONCLUSIONS

Time-updated changes (increase or decrease) of the AIs, BMI, WHR and weight height ratio are independently associated with the mortality of patients with incident HF.

Statin therapy decreases N-terminal pro-B-type natriuretic peptide in HIV: randomized placebo-controlled trial

OBJECTIVE

HIV-infected participants are at a higher risk for cardiovascular disease (CVD). N-terminal pro-B-type natriuretic peptide (NT-proBNP) is a significant predictor of CVD in the general population and is associated with mortality in HIV.

DESIGN AND METHODS

The 96-week Stopping Atherosclerosis and Treating Unhealthy Bone with Rosuvastatin in HIV (SATURN-HIV) trial randomized 147 patients on stable antiretroviral therapy with low-density lipoprotein-cholesterol level lower than 130 mg/dl and without overt heart failure to 10 mg daily rosuvastatin or placebo. We measured NT-proBNP levels by enzyme-linked immunosorbent assay (ELISA). Baseline and changes in NT-proBNP were compared between groups. Spearman correlation was used to explore relationships between baseline NT-proBNP, inflammation, and CVD risk markers. Multivariable analyses were conducted to assess associations with NT-proBNP levels.

RESULTS

Median age was 46 years, 80% were men, 69% were African American, and 46% were on protease inhibitors. At baseline, median (Q1, Q3) NT-proBNP was higher in the rosuvastatin group than placebo [41 (20, 66.5) versus 25 pg/ml (11, 56), P = 0.012)]. Baseline NT-proBNP correlated with bulb and common carotid artery intima-media thickness, coronary calcium score, interleukin 6, and cystatin C. After 96 weeks, median NT-proBNP decreased significantly in the rosuvastatin group versus placebo (-1.50 versus +4.50 pg/ml, P = 0.041). Within the rosuvastatin group, changes in NT-proBNP were negatively correlated with changes in insulin resistance and total limb fat.

CONCLUSION

Rosuvastatin reduces plasma NT-proBNP in HIV-infected participants on antiretroviral therapy. NT-proBNP correlated with several measures of CVD risk, independent of inflammation markers.

Obstructive sleep apnea is independently associated with worse diastolic function in coronary artery disease

BACKGROUND

Diastolic dysfunction is common in patients with coronary artery disease (CAD). We hypothesize that patients with CAD and preserved left ventricular ejection fraction (LVEF) and obstructive sleep apnea (OSA) will have worse diastolic function than similar patients without OSA.

MATERIAL AND METHODS

We analyzed sleep-study recordings and echocardiographic measurements obtained at baseline in a randomized controlled trial (RICCADSA) of revascularized patients with CAD who had LVEF of at least 50%. OSA was defined as an apnea-hypopnea-index (AHI) ≥15 events/h, and, no OSA, as an AHI <5. Worse diastolic function was defined as assumed elevated left ventricular filling pressure based on peak flow velocity in early diastole/Tissue Doppler of early diastolic ventricular filling (E/é) of >13 (or >9 in patients with an enlarged left atrial diameter [≥39 mm for women and ≥40 mm for men]).

RESULTS

Data from 431 patients were evaluated (mean age: 63.7 ± 8.8 y; men: 82.5%; OSA: n = 331). Worse diastolic function was more common among the patients with OSA than those without (54.4% vs 41.0%, p = 0.019). In multivariate analysis, OSA was associated with worse diastolic function (odds ratio [OR] 1.90, 95% confidence interval [CI] 1.13; 3.18) adjusted for female sex (OR 2.28, 95% CI 1.28; 4.07), hypertension (OR 1.84, 95% CI 1.20; 2.82), and diabetes mellitus (OR 2.45, 95% CI 1.42; 4.23). Age ≥60 years, obesity, and current smoking were nonsignificant.

CONCLUSIONS

In this cohort with CAD and preserved LVEF, OSA was associated with worse diastolic function independent of the traditionally recognized risk indicators.

Brain natriuretic hormone predicts stress-induced alterations in diastolic function

BACKGROUND

Mental stress (MS) reduces diastolic function (DF) and may lead to congestive heart failure with preserved systolic function. Whether brain natriuretic hormone (brain natriuretic peptide [BNP]) mediates the relationship of MS with DF is unknown.

METHODS

One hundred sixty individuals aged 30 to 50 years underwent 2-hour protocol of 40-minute rest, videogame stressor and recovery. Hemodynamics, pro-BNP samples and DF indices were obtained throughout the protocol. Separate regression analyses were conducted using rest and stress E/A, E' and E/E' as dependent variables. Predictor variables were entered into the stepwise regression models in a hierarchical fashion. At the first level, age, sex, race, height, body mass index, pro-BNP and left ventricular mass (LVM) were permitted to enter the models. The second level consisted of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). The final level contained cross-product terms of race by SBP, DBP and HR.

RESULTS

E/A ratio was lower during stress compared to rest and recovery (P < 0.01). Resting E/A ratio was predicted by a regression model of age (-0.31), pro-BNP (0.16), HR (-0.40) and DBP (-0.23) with an R² = 0.33. Stress E/A ratio was predicted by age (-0.24), pro-BNP (0.08), HR (-0.38) and SBP (-0.21) with total R² = 0.22. Resting E' model consisted of age (-0.22), pro-BNP (0.26), DBP (-0.27) and LVM (-0.15) with an R² = 0.29. Stress E' was predicted by age (-0.18), pro-BNP (0.35) and LVM (-0.18) with an R² = 0.18. Resting E/E' was predicted by race (0.17, B > W) and DBP (0.24) with an R² = 0.10. Stress E/E' consisted of pro-BNP (-0.36), height (-0.26) and HR (-0.21) with an R² = 0.15.

CONCLUSIONS

pro-BNP predicts both resting and stress DF, suggesting that lower BNP during MS may be a marker of diastolic dysfunction in apparently healthy individuals.

Metabolic rather than body composition measurements are associated with lower serum natriuretic peptide concentrations in normal weight and obese men

BACKGROUND

Several studies have shown that obese persons have lower circulating natriuretic peptide (NP) concentrations. The cause of the relative NP deficiency seen in obese persons is poorly understood, although variation in body composition and metabolic abnormalities has been suggested to play a role. Thus, the aim of this study was to assess whether variation in circulating NP concentrations would be associated with differences in metabolic disturbances rather than with differences in body composition.

METHODS

In 27 normal weight men (body mass index (BMI) = 20.0-24.9kg/m(2)) and 103 obese men (BMI ≥ 30kg/m(2)), we determined body composition (total, android, and gynoid fat mass) by dual energy x-ray absorptiometry scanning, and we measured fasting serum concentrations of midregional proatrial NP (MR-proANP) and insulin, as well as fasting plasma glucose concentrations.

RESULTS

Mean weight ± SD was 74.9±6.7kg in the normal weight men and 106.1±10.8kg in obese men. Applying multiple regressions, adjusting for age and weight status (normal weight vs. obese), serum MR-proANP concentrations were significantly inversely associated with serum insulin concentrations (β = -0.39; P < 0.0001) and plasma glucose concentrations (β = -0.21; P = 0.02) but not with total (β = 0.00), android (β = -0.01), or gynoid (β = 0.03) fat mass percentage (P > 0.76). No significant interaction effects between metabolic measurements or body composition measurements and weight status on MR-proANP concentrations were found (P > 0.08).

CONCLUSIONS

In normal weight and obese men, lower circulating NP concentrations are associated with higher insulin and glucose concentrations and not with the proportion of total fat mass or the distribution of fat mass.

Natriuretic peptides: molecular biology, pathophysiology and clinical implications for the cardiologist

Natriuretic peptides (NPs) counter the effects of volume overload or adrenergic activation of the cardiovascular system. They are able to induce arterial vasodilatations, natriuresis and diuresis, and they reduce the activities of the renin-angiotensin-aldosterone system and the sympathetic nervous system. However, in addition to wall stress, other factors have been associated with elevated natriuretic peptide levels. Since 2000, because of their characteristics, NPs have become quantitative plasma biomarkers of heart failure. Nowadays, NPs play an important role not only in the diagnosis of heart failure, but also for a prognostic purpose and a guide to medical therapy. Finally, a new drug that modulates the NP system or recombinant analogs of NPs are now available in patients with heart failure.

Unexpected effects of voluntary exercise training on natriuretic peptide and receptor mRNA expression in the ob/ob mouse heart

Regular exercise is generally recommended for the treatment of obesity and type 2 diabetes. Exercise reduces body weight, improves glycemic control and cardiovascular (CV) function. This study was designed to determine the impact of voluntary wheel running on the cardiac oxytocin (OT)-natriuretic peptide (NP) system and plasma CV risk factors in the ob/ob mouse, a model of insulin resistance coupled with severe obesity. Five-week-old male ob/ob mice and non-obese heterozygote control littermates were assigned to either a sedentary or running group. Voluntary running was performed using a wheel system for a period of 8 weeks. Compared to non-obese mice, daily running activity expressed in kilometers, was significantly lower in ob/ob mice. In these mice, voluntary running improved body weight, but exacerbated CV markers, including plasma glucose and triglyceride levels. OT receptor gene expression was decreased in hearts of ob/ob mice compared to non-obese mice, and no improvement in the expression of this receptor was observed after voluntary running. Hearts from ob/ob mice also expressed lower BNP mRNA, whereas no differences in A- and C-type NP were observed between non-obese and ob/ob mice. After voluntary running, a downregulation in the expression of all three NPs coupled with increased apoptosis was observed in ob/ob hearts. Our results show that voluntary exercise running activity was decreased in the ob/ob mouse. Surprisingly, this was associated with a worsening of common CV plasma markers, reduced expression of peptides linked to the cardioprotective OT-NP system, and increased expression of cardiac apoptotic markers.

Decreased plasma B-type natriuretic peptide levels in obesity are not explained by altered left ventricular hemodynamics

SUMMARY

BACKGROUND

Although obesity has been reported to be associated with decreased plasma B-type natriuretic peptide (BNP) levels, it is unknown whether the reduced BNP levels in obesity results from decreased left ventricular (LV) hemodynamic load.

METHODS

We examined the relationships between body mass index (BMI), plasma BNP levels, and LV systolic and diastolic function (ejection fraction [EF] and end-diastolic pressure [EDP]) in 271 consecutive patients undergoing cardiac catheterization for coronary artery disease. When patients were grouped by tertile of BMI, with increasing tertiles of BMI, there was a progressive increase in EDP (lower, middle, and upper tertiles of BMI, 13.5 ± 5.8, 14.9 ± 5.3, and 16.3 ± 5.4 mmHg, respectively; p for trend <0.01) and a progressive decrease in log BNP levels (lower, middle, and upper tertiles of BMI, 3.52 ± 1.29, 2.96 ± 1.08, and 2.87 ± 1.21 ln[pg/ml], respectively, p for trend < 0.001). There was no clear difference in EF across BMI tertiles (p for trend >0.1). Plasma BNP levels correlated positively with EDP (r = 0.38, p < 0.001). In multivariate linear regression including EDP and known correlates of plasma BNP levels, BMI correlated negatively with BNP levels (standardized β = -0.31, p < 0.001).

CONCLUSIONS

We found that increased BMI was associated with LV diastolic abnormalities without change in systolic function and that patients with increased BMI had reduced plasma BNP levels despite having elevated EDP. These results suggest that the reduced BNP levels in obesity are not explained by altered LV hemodynamics.

The obesity paradox in men with coronary heart disease and heart failure: the role of muscle mass and leptin

AIMS

We have investigated the role of muscle mass, natriuretic peptides and adipokines in explaining the obesity paradox.

BACKGROUND

The obesity paradox relates to the association between obesity and increased survival in patients with coronary heart disease (CHD) or heart failure (HF).

METHODS

Prospective study of 4046 men aged 60-79 years followed up for a mean period of 11 years, during which 1340 deaths occurred. The men were divided according to the presence of doctor diagnosed CHD and HF: (i) no CHD or HF ii), with CHD (no HF) and (iii) with HF.

RESULTS

Overweight (BMI 25-9.9 kg/m(2)) and obesity (BMI ≥ 30 kg/m(2)) were associated with lower mortality risk compared to men with normal weight (BMI 18.5-24.9 kg/m(2)) in those with CHD [hazards ratio (HR) 0.71 (0.56,0.91) and 0.77 (0.57,1.04); p=0.04 for trend] and in those with HF [HR 0.57 (0.28,1.16) and 0.41 (0.16,1.09; p=0.04 for trend). Adjustment for muscle mass and NT-proBNP attenuated the inverse association in those with CHD (no HF) [HR 0.78 (0.61,1.01) and 0.96 (0.68,1.36) p=0.60 for trend) but made minor differences to those with HF [p=0.05]. Leptin related positively to mortality in men without HF but inversely to mortality in those with HF; adjustment for leptin abolished the BMI mortality association in men with HF [HR 0.82 (0.31,2.20) and 0.99 (0.27,3.71); p=0.98 for trend].

CONCLUSION

The lower mortality risk associated with excess weight in men with CHD without HF may be due to higher muscle mass. In men with HF, leptin (possibly reflecting cachexia) explain the inverse association.

Inverse association of N-terminal pro-B-type natriuretic peptide with metabolic syndrome in patients with congestive heart failure

BACKGROUND

Metabolic syndrome has been shown to be associated with lower levels of plasma N-terminal pro-B-type natriuretic peptide (Nt-proBNP) in the general population. We sought to elucidate the relationship between Nt-proBNP and components of metabolic syndrome in patients with congestive heart failure (CHF).

METHODS

Fasting blood samples were obtained from 93 patients in our institution. Plasma levels of Nt-proBNP and other biochemical data were measured. The New York Heart Association (NYHA) classification system (I-IV) was used to define the functional capacity of CHF. Metabolic syndrome and its components were defined using diagnostic criteria from the International Diabetes Federation.

RESULTS

Forty-nine patients (52.7%) had CHF. There was a positive correlation between plasma Nt-proBNP levels and NYHA functional capacity in CHF patients. Plasma Nt-proBNP levels increased significantly with each increasing NYHA class of the disease. The prevalence of metabolic syndrome in CHF patients was higher than that in patients without CHF. Most importantly, we found that plasma Nt-proBNP levels were lower in CHF patients with metabolic syndrome attributable to inverse relationships between plasma Nt-proBNP and body mass index (β = -0.297), plasma triglyceride (β = -0.286) and homeostasis model assessment of insulin resistance (HOMA-IR; β = -0.346). Fasting glucose to insulin ratio (FGIR, an insulin sensitivity index) was positively associated with plasma Nt-proBNP levels (β = 0.491), and was the independent predictor of plasma Nt-proBNP levels in CHF patients.

CONCLUSIONS

Plasma Nt-proBNP levels are inversely associated with metabolic syndrome in CHF patients. Reduced plasma Nt-proBNP levels in CHF patients may lead to impaired lipolysis and metabolic function, and may contribute to the development of metabolic syndrome in CHF patients.

Obesity in heart failure: impact on survival and treatment modalities

Heart failure (HF) and obesity are commonly seen in the USA. Although obesity is associated with traditional cardiovascular disease, its relationship with HF is complex. Obesity is an accepted risk factor for incident HF. However, in patients with established HF, there exists a paradoxical correlation, with escalating BMI incrementally protective against adverse outcomes. Despite this relationship, patients with HF may desire to lose weight to reduce comorbidities or to improve quality of life. Thus far, studies have shown that intentional weight loss in obese patients with HF does not increase risk, with strategies including dietary modification, physical activity, pharmacotherapy, and/or surgical intervention.

Cardiac production of B-type natriuretic peptide is inversely related to the plasma level of free fatty acids in obese individuals - possible involvement of the insulin resistance -

B-type natriuretic peptide (BNP) is produced by the heart and its plasma level is increased with the severity of left ventricular (LV) dysfunction/hypertrophy. The normal heart preferentially utilizes fatty acids as energy substrates. Plasma BNP levels are reported to be lower in obese individuals. We examined the relationship between BNP production and plasma free fatty acids (FFA), homeostasis model assessment of insulin resistance (HOMA-IR), and LV dysfunction/ hypertrophy. We examined the plasma BNP levels and FFA at the aortic root (AO) and coronary sinus (CS) as well as hemodynamic parameters in 62 patients (38 men and 24 women, 62.5±11.7 yrs) who underwent cardiac catheterization. Log BNP (AO) had a significant positive correlation with log BNP (CS-AO) (r=0.877, P<0.001). Log BNP(CS-AO) had a significant negative correlation with BMI (r=-0.558, P<0.001), waist circumference (WC) (r=-0.574, P<0.001), log FFA(AO) (r=-0.643, P<0.001), log triglyceride (r=-0.431, P<0.001), and log HOMA-IR (r=-0.463, P<0.001) and a significant positive correlation with left ventricular mass index (LVMI) (r=0.403, P=0.001). The multivariable regression analyses including log HOMA-IR, LVMI, and age as an independent variable revealed that HOMA-IR and LVMI were significant predictors of log BNP (CS-AO) or BNP production (P=0.001 and 0.004, respectively). We conclude that plasma BNP levels are determined primarily by cardiac production and that insulin resistance is a significant predictor of cardiac BNP production independent of LV hypertrophy in obese individuals.