Midregional pro-atrial natriuretic peptide in the general population/Insights from the Gutenberg Health Study

Plasma N-terminal pro-B-type natriuretic peptide in the detection of aortic valve stenosis

BACKGROUND

Systolic murmur suggestive of aortic valve origin is a common accidental finding, particularly in the elderly. Usually, it is due to aortic stenosis (AS) or aortic sclerosis (ASc). Currently, echocardiography is used to differentiate AS from ASc. Plasma N-terminal (NT)-prohormone BNP (NT-proBNP) is known to correlate with the severity of AS. We assessed whether NT-proBNP separates AS from ASc.

METHODS

The study population consisted of three groups: AS (n = 87, age 77 ± 7 years), ASc (n = 76, age 72 ± 10 years), and healthy controls (n = 101, age 55 ± 10 years). All subjects underwent transthoracic echocardiography and measurement of plasma NT-proBNP. Patients with diseases known to increase NT-proBNP were excluded.

RESULTS

The crude plasma NT-proBNP (median; IQR) in AS patients (413; 165-1055 ng/l) was significantly higher compared to ASc patients (96; 53-237 ng/l, p < 0.001) and healthy controls (50; 29-76 ng/l, p < 0.001). After adjusting for the confounding factors (age, coronary artery disease, renal function and diastolic blood pressure), plasma NT-proBNP remained significantly higher in AS patients as compared to ASc (p < 0.002) and controls (p < 0.0001). In the receiver-operating characteristic curve for NT-proBNP to identify AS from ASc and controls, the area under the curve was 0.878 with optimal cutoff of 115 ng/l. In addition, using 115 ng/l to separate AS from ASc yielded sensitivity of 0.885, and negative predictive value of 0.808.

CONCLUSIONS

NT-proBNP was sensitive to identify AS and useful to rule out AS in patients with systolic murmur in the left ventricular outflow tract provided the patient does not have coexisting disease known to impact NT-proBNP.

Atrial Natriuretic Peptides as a Bridge between Atrial Fibrillation, Heart Failure, and Amyloidosis of the Atria

ANP is mainly synthesized by the atria, and upon excretion, it serves two primary purposes: vasodilation and increasing the renal excretion of sodium and water. The understanding of ANP's role in cardiac systems has improved considerably in recent decades. This review focuses on several studies demonstrating the importance of analyzing the regulations between the endocrine and mechanical function of the heart and emphasizes the effect of ANP, as the primary hormone of the atria, on atrial fibrillation (AF) and related diseases. The review first discusses the available data on the diagnostic and therapeutic applications of ANP and then explains effect of ANP on heart failure (HF) and atrial fibrillation (AF) and vice versa, where tracking ANP levels could lead to understanding the pathophysiological mechanisms operating in these diseases. Second, it focuses on conventional treatments for AF, such as cardioversion and catheter ablation, and their effects on cardiac endocrine and mechanical function. Finally, it provides a point of view about the delayed recovery of cardiac mechanical and endocrine function after cardioversion, which can contribute to the occurrence of acute heart failure, and the potential impact of restoration of the sinus rhythm by extensive ablation or surgery in losing ANP-producing sites. Overall, ANP plays a key role in heart failure through its effects on vasodilation and natriuresis, leading to a decrease in the activity of the renin-angiotensin-aldosterone system, but it is crucial to understand the intimate role of ANP in HF and AF to improve their diagnosis and personalizing the patients' treatment.

Reference Ranges for NT-proBNP (N-Terminal Pro-B-Type Natriuretic Peptide) and Risk Factors for Higher NT-proBNP Concentrations in a Large General Population Cohort

BACKGROUND

Demographic differences in expected NT-proBNP (N-terminal pro-B-type natriuretic peptide) concentration are not well established. We aimed to establish reference ranges for NT-proBNP and explore the determinants of moderately elevated NT-proBNP under the universal definition of heart failure criteria.

METHODS

This is a cross-sectional study. NT-proBNP was measured in serum from 18 356 individuals without previous cardiovascular disease in the Generation Scotland Scottish Family Health Study. Age- and sex-stratified medians and 97.5th centiles were generated. Sex stratified risk factors for moderately elevated NT-proBNP (≥125 pg/mL) were investigated.

RESULTS

In males, median (97.5th centile) NT-proBNP concentration at age <30 years was 21 (104) pg/mL, rising to 38 (195) pg/ml at 50 to 59 years, and 281 (6792) pg/mL at ≥80 years. In females, median NT-proBNP at age <30 years was 51 (196) pg/mL, 66 (299) pg/mL at 50 to 59 years, and 240 (2704) pg/mL at ≥80 years. At age <30 years, 9.8% of females and 1.4% of males had elevated NT-proBNP, rising to 76.5% and 81.0%, respectively, at age ≥80 years. After adjusting for risk factors, an NT-proBNP ≥125 pg/mL was more common in females than males (OR, 9.48 [95% CI, 5.60-16.1]). Older age and smoking were more strongly associated with elevated NT-proBNP in males than in females (Psex interaction <0.001, 0.07, respectively). Diabetes was inversely associated with odds of elevated NT-proBNP in females only (Psex interaction=0.007).

CONCLUSIONS

An NT-proBNP ≥125 pg/mL is common in females without classical cardiovascular risk factors as well as older people. If NT-proBNP becomes widely used for screening in the general population, interpretation of NT-proBNP levels will require that age and sex-specific thresholds are used to identify patients with potential pathophysiology.

NT-ProBNP and high-sensitivity troponin T as screening tests for subclinical chronic heart failure in a general population

Aims

The aim of this study was to establish age‐specific and sex‐specific cut‐off values for N‐terminal pro‐brain natriuretic peptide (NT‐proBNP) and high‐sensitivity troponin T (hs‐troponin T) in healthy subjects and assess cardiac biomarkers as screening tools for subclinical heart failure (HF) in a general population.

Methods and results

Altogether, 1936 participants were randomly selected from the general population Tromsø 7 study in Northern Norway. Diagnostic accuracy (sensitivity, specificity, and negative and positive predictive value) of cardiac markers for echocardiographically defined subclinical HF was evaluated. The receiver‐operating characteristic analysis showed that areas under the curve were relatively low (under 0.75) for both NT‐proBNP and hs‐troponin T, suggesting that the diagnostic accuracy of these biomarkers for subclinical HF was not excellent, especially for mild forms of HF and younger age group 40–49 years. Sex‐specific and age‐specific cut‐offs for hs‐troponin T (99th percentiles) and NT‐proBNP (97.5th percentiles) were established in healthy subjects from the same general population. The sex‐specific and age‐specific cut‐offs for NT‐proBNP had higher specificity for subclinical HF compared with the previously established single cut‐off 125 pg/mL. Age‐specific cut‐off for hs‐troponin T (18 ng/L) for men ≥60 years had also higher specificity than the single cut‐off 14 ng/L. These cut‐offs had high specificity, but low sensitivity, that makes hs‐troponin T and NT‐proBNP good biomarkers to rule in HF in case of a positive test, but not good enough to rule out all unrecognized HF due to false negative results.

Conclusions

N‐terminal pro‐brain natriuretic peptide and hs‐troponin T are suboptimal screening tools for subclinical HF in a general population due to low sensitivity.

Biomarkers Associated with Cardiovascular Disease in COVID-19

Coronavirus disease-19 (COVID-19) emerged late December 2019 in the city of Wuhan, China and has since spread rapidly all over the world causing a global pandemic. While the respiratory system is the primary target of disease manifestation, COVID-19 has been shown to also affect several other organs, making it a rather complex, multi-system disease. As such, cardiovascular involvement has been a topic of discussion since the beginning of the COVID-19 pandemic, primarily due to early reports of excessive myocardial injury in these patients. Treating physicians are faced with multiple challenges in the management and early triage of patients with COVID-19, as disease severity is highly variable ranging from an asymptomatic infection to critical cases rapidly deteriorating to intensive care treatment or even fatality. Laboratory biomarkers provide important prognostic information which can guide decision making in the emergency department, especially in patients with atypical presentations. Several cardiac biomarkers, most notably high-sensitive cardiac troponin (hs-cTn) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), have emerged as valuable predictors of prognosis in patients with COVID-19. The purpose of this review was to offer a concise summary on prognostic cardiac biomarkers in COVID-19 and discuss whether routine measurements of these biomarkers are warranted upon hospital admission.

Natriuretic peptides in heart failure: Current achievements and future perspectives

The last two centuries have witnessed countless discoveries in the field of medicine that found their roots in the up growing development of technology as well as in the visionary ideas of brilliant scientists and research groups. One of the most important discoveries in the field of cardiovascular medicine allowed to break the paradigm identifying the heart with mere mechanical pump and to characterize its intriguing endocrine properties. Indeed, the discovery of hormones produced by the cardiac chambers, the natriuretic peptides, represents one of the milestones of the current conception of complexity of integrated human physiology. In the last four decades, the role of these hormones in the regulation of the cardiovascular system, in physiology and diseases, has been defined piece after piece. From diagnostic and prognostic markers, natriuretic peptides have become one of the most relevant clinical biomarker and a reliable target for establishing the efficacy of therapies. Recently and successfully, natriuretic peptide-based strategies are proposed as therapeutic weapons to improve outcome in heart failure. The future will witness potential further therapeutic application of natriuretic peptides that are currently being actively investigated.

Effect of liraglutide on atrial natriuretic peptide, adrenomedullin, and copeptin in PCOS

CONTEXT

Women with polycystic ovary syndrome (PCOS) have an increased risk of cardiovascular disease (CVD), and biomarkers can be used to detect early subclinical CVD. Midregional-pro-adrenomedullin (MR-proADM), midregional-pro-atrial natriuretic peptide (MR-proANP) and copeptin are all associated with CVD and part of the delicate system controlling fluid and hemodynamic homeostasis through vascular tonus and diuresis. The GLP-1 receptor agonist liraglutide, developed for treatment of type 2 diabetes (T2D), improves cardiovascular outcomes in patients with T2D including a decrease in particular MR-proANP.

OBJECTIVE

To investigate if treatment with liraglutide in women with PCOS reduces levels of the cardiovascular biomarkers MR-proADM, MR-proANP and copeptin.

METHODS

Seventy-two overweight women with PCOS were treated with 1.8 mg/day liraglutide or placebo for 26 weeks in a placebo-controlled RCT. Biomarkers, anthropometrics, insulin resistance, body composition (DXA) and visceral fat (MRI) were examined.

RESULTS

Baseline median (IQR) levels were as follows: MR-proADM 0.52 (0.45-0.56) nmol/L, MR-proANP 44.8 (34.6-56.7) pmol/L and copeptin 4.95 (3.50-6.50) pmol/L. Mean percentage differences (95% CI) between liraglutide and placebo group after treatment were as follows: MR-proADM -6% (-11 to 2, P = 0.058), MR-proANP -25% (-37 to -11, P = 0.001) and copeptin +4% (-13 to 25, P = 0.64). Reduction in MR-proANP concentration correlated with both increased heart rate and diastolic blood pressure in the liraglutide group. Multiple regression analyses with adjustment for BMI, free testosterone, insulin resistance, visceral fat, heart rate and eGFR showed reductions in MR-proANP to be independently correlated with an increase in the heart rate.

CONCLUSION

In an RCT, liraglutide treatment in women with PCOS reduced levels of the cardiovascular risk biomarkers MR-proANP with 25% and MR-proADM with 6% (borderline significance) compared with placebo. The decrease in MR-proANP was independently associated with an increase in the heart rate.

Processing-independent proANP measurement for low concentrations in plasma: reference intervals and effect of body mass index and plasma glucose

BACKGROUND

Decreased concentrations of pro-atrial-derived natriuretic peptides (proABP) in plasma have been associated with obesity and suggested as a predictor of type 2 diabetes. However, assays for measuring proANP are generally aimed to quantitate higher concentrations of proANP associated with cardiac disease. Therefore, we aimed to measure plasma proANP concentrations in a non-obese Scandinavian reference material and evaluate potential associations of plasma proANP with body mass index (BMI) and plasma glucose, respectively.

METHODS

We report an optimized processing-independent assay (PIA) for proANP in the lower concentration range. The assay was optimized by raising the amount of radioactive tracer and modifying the mixing ratio of resuspended plasma and buffer. Blood samples from a Scandinavian plasma cohort of 693 healthy subjects were then analyzed and age and gender-specific reference intervals were determined.

RESULTS

Simple linear regression analyses of proANP and both BMI and plasma glucose in fasting subjects displayed insignificant associations. Multiple regression analyses supported these findings. However, a higher median plasma concentration of proANP was noted among women <50 years compared to men, whereas no gender-specific differences were seen in other age groups.

CONCLUSIONS

Our results show that in a healthy non-obese population, BMI and plasma glucose in fasting subjects do not affect plasma proANP concentrations. Our method should be considered for future studies on low proANP concentration studies, e.g. in obesity and diabetes.

Plasma proANP1-98 levels are positively associated with central obesity: A cross-sectional study in a general population of China

BACKGROUND

Atrial natriuretic peptide (ANP) and its prohormone activating enzyme are associated with central obesity, suggesting there may be a potential relationship between proANP_1-98 and central obesity. However, the association is still lack of population-based evidence. We explored the association in a general population of China.

METHODS

We measured plasma proANP_1-98, waist circumference and other traditional biomarkers in 2203 participants aged≥30y. Multivariate logistic regression models were used to determine the association between plasma proANP_1-98 and central obesity, and odds ratio (OR) and 95% confidence interval (CI) were calculated.

RESULTS

High proANP_1-98 was significantly associated with increased risk of central obesity in participants, and the multivariate adjusted OR (95% CI) of central obesity associated with the second, third and fourth quartiles of proANP_1-98 were 1.33 (1.03-1.72), 1.69 (1.31-2.19) and 1.76 (1.35-2.29), respectively, compared with the lowest quartile of proANP_1-98. There was a dose-response relationship between proANP_1-98 and risk of central obesity among the participants (P_trend<0.001). Sensitivity analyses further confirmed these associations. Adding proANP_1-98 to a model containing conventional risk factors improved discriminatory power of central obesity (as shown by significant improvement in continuous NRI and IDI).

CONCLUSIONS

Contrary to known reduced ANP levels in central obesity, we found that plasma proANP_1-98 was positively associated with central obesity, suggesting that elevated plasma proANP_1-98 may be a marker or a risk factor for central obesity.

Diagnosis and Treatment of Hyponatremia: Compilation of the Guidelines

Hyponatremia is a common water balance disorder that often poses a diagnostic or therapeutic challenge. Therefore, guidelines were developed by professional organizations, one from within the United States (2013) and one from within Europe (2014). This review discusses the diagnosis and treatment of hyponatremia, comparing the two guidelines and highlighting recent developments. Diagnostically, the initial step is to differentiate hypotonic from nonhypotonic hyponatremia. Hypotonic hyponatremia is further differentiated on the basis of urine osmolality, urine sodium level, and volume status. Recently identified parameters, including fractional uric acid excretion and plasma copeptin concentration, may further improve the diagnostic approach. The treatment for hyponatremia is chosen on the basis of duration and symptoms. For acute or severely symptomatic hyponatremia, both guidelines adopted the approach of giving a bolus of hypertonic saline. Although fluid restriction remains the first-line treatment for most forms of chronic hyponatremia, therapy to increase renal free water excretion is often necessary. Vasopressin receptor antagonists, urea, and loop diuretics serve this purpose, but received different recommendations in the two guidelines. Such discrepancies may relate to different interpretations of the limited evidence or differences in guideline methodology. Nevertheless, the development of guidelines has been important in advancing this evolving field.

Plasma concentrations of novel cardiac biomarkers before and after hemodialysis session

OBJECTIVES

Biomarkers are useful for establishing disease severity or prognosis in patients with chronic kidney disease. The aim of our study was to determine the plasma concentrations of novel cardiovascular biomarkers in patients on chronic hemodialysis in the context of published upper reference limits (URL) of these biomarkers; and to compare the plasma concentrations of those same analytes before and after hemodialysis session.

DESIGN AND METHODS

Plasma concentrations of N-terminal pro-B-type natriuretic peptide (NT-proBNP), mid-regional pro-A-type natriuretic peptide (MR-proANP), mid-regional pro-adrenomedullin (MR-proADM), C-terminal pro-endothelin-1 (CT-proET-1), C-terminal pro-arginine vasopressin (CT-proAVP, also known as Copeptin) and soluble ST2 (sST2) were measured in 28 patients before and after dialysis session. Of the 28 patients with conventional hemodialysis, 24 had low-flux hemofiltration and 4 had high-flux hemodiafiltration.

RESULTS

Median plasma concentrations of the biomarkers obtained before hemodialysis were as follows: NT-proBNP, 11,307ng/L (URL, 500ng/L); MR-proANP, 778pmol/L (URL, 250pmol/L); MR-proADM, 2.57nmol/L (URL, 0.52nmol/L); median CT-proET-1, 252pmol/L (URL, 75pmol/L); median CT-proAVP, 142pmol/L (URL, 19pmol/L); and median sST2, 27ng/mL (URL, 50ng/mL). Median relative analyte changes after low-flux vs. high-flux dialysis compared to predialysis values were +19% vs. -43% for NT-proBNP; +7% vs. -45% for MR-proANP; -2% vs. -63% for MR-proADM; -19% vs. -61% for CT-proET-1; +13% vs. -64% for CT-proAVP; and +2% vs. +3% for sST2.

CONCLUSIONS

Plasma concentrations of the investigated biomarkers were markedly increased in chronic hemodialysis patients (with the exception of sST2). After hemodialysis session, analyte concentrations (with the exception of sST2) decreased significantly using a high-flux membrane but not if using a low-flux membrane.

Mid-regional pro-atrial natriuretic peptide and the assessment of volaemic status and differential diagnosis of profound hyponatraemia

BACKGROUND

Hyponatraemia is common and its differential diagnosis and consequent therapy management is challenging. The differential diagnosis is mainly based on the routine clinical assessment of volume status, which is often misleading. Mid-regional pro-atrial natriuretic peptide (MR-proANP) is associated with extracellular and cardiac fluid volume.

METHODS

A total of 227 consecutive patients admitted to the emergency department with profound hypo-osmolar hyponatraemia (Na < 125 mmol L(-1) ) were included in this prospective multicentre observational study conducted in two tertiary centres in Switzerland. A standardized diagnostic evaluation of the underlying cause of hyponatraemia was performed, and an expert panel carefully evaluated volaemic status using clinical criteria. MR-proANP levels were compared between patients with hyponatraemia of different aetiologies and for assessment of volume status.

RESULTS

MR-proANP levels were higher in patients with hypervolaemic hyponatraemia compared to patients with hypovolaemic or euvolaemic hyponatraemia (P = 0.0002). The area under the curve (AUC) to predict an excess of extracellular fluid volume, compared to euvolaemia, was 0.73 [95% confidence interval (CI) 0.62-0.84]. Additionally, in multivariate analysis, MR-proANP remained an independent predictor of excess extracellular fluid volume after adjustment for congestive heart failure (P = 0.012). MR-proANP predicted the syndrome of inappropriate antidiuresis (SIAD) versus hypovolaemic and hypervolaemic hyponatraemia with an AUC of 0.77 (95% CI 0.69-0.84).

CONCLUSION

MR-proANP is associated with extracellular fluid volume in patients with hyponatraemia and remains an independent predictor of hypervolaemia after adjustment for congestive heart failure. MR-proANP may be a marker for discrimination between the SIAD and hypovolaemic or hypervolaemic hyponatraemia.

Association of multiple biomarkers and classical risk factors with early carotid atherosclerosis: results from the Gutenberg Health Study

BACKGROUND

In the Gutenberg Health Study, a random sample of the population was scanned with vascular ultrasound for early atherosclerosis. A continuous classical risk marker model (waist circumference, HbA1c, LDL/HDL ratio, pack years and pulse pressure) was compared to a model of modern biomarkers (C-reactive protein, troponin I, N-terminal pro B-type natriuretic peptide, copeptin, mid-regional pro-adrenomedullin, and asymmetric dimethylarginine) with regard to the ability of ruling out abnormal intima-media thickness (IMT), respectively, carotid plaques.

METHODS

Data of the first consecutive 5,000 participants (aged 35-74 years; 2,540 men, 2,460 women) were analyzed. IMT was measured at both common carotid arteries using an edge detection system. Plaques were defined as protrusion of ≥1.5 mm in common, internal and external carotid artery.

RESULTS

For classical risk factors, in comparison to a model of six modern biomarkers, regarding the variable (a) IMT>0.85 mm negative and positive predictive value (NPV and PPV) were 0.98 and 0.16 for both the classical risk factor model and the biomarker model. The second variable (b) presence of plaque could be ruled out with an NPV of 0.84 and identified with a PPV of 0.61 for classical risk factors, and 0.84 and 0.58 for biomarkers, respectively. Values were calculated using logistic regression analysis.

CONCLUSION

Classical risk factors allow ruling out pathologic IMT and presence of carotid plaques in a population of primary prevention in a reliable way. Modern biomarkers performed almost equally well but did not provide further information.