Type 2 Myocardial Infarction: Evolving Approaches to Diagnosis and Risk-Stratification.

BACKGROUND: Type 2 myocardial infarction (T2MI) is frequently encountered in clinical practice and associated with adverse outcomes. CONTENT: T2MI occurs most frequently due to noncoronary etiologies that alter myocardial oxygen supply and/or demand. The diagnosis of T2MI is often confused with acute nonischemic myocardial injury, in part because of difficulties in delineating the nature of symptoms and misunderstandings about disease categorization. The use of objective features of myocardial ischemia using electrocardiographic (ECG) or imaging abnormalities may facilitate more precise T2MI diagnosis. High-sensitivity cardiac troponin (hs-cTn) assays allow rapid MI diagnosis and risk stratification, yet neither maximum nor delta values facilitate differentiation of T2MI from T1MI. Several investigational biomarkers have been evaluated for T2MI, but none have robust data. There is interest in evaluating risk profiles among patients with T2MI. Clinically, the magnitude of maximum and delta cTn values as well as the presence and magnitude of ischemia on ECG or imaging is used to indicate disease severity. Scoring systems such as GRACE, TIMI, and TARRACO have been evaluated, but all have limited to modest performance, with substantial variation in time intervals used for risk-assessment and endpoints used. SUMMARY: The diagnosis of T2MI requires biomarker evidence of acute myocardial injury and clear clinical evidence of acute myocardial ischemia without atherothrombosis. T2MIs are most often caused by noncoronary etiologies that alter myocardial oxygen supply and/or demand. They are increasingly encountered in clinical practice and associated with poor short- and long-term outcomes. Clinicians require novel biomarker or imaging approaches to facilitate diagnosis and risk-stratification.

The role of natriuretic peptide estimation in severe COVID-19.

Since its inception in Wuhan in December 2019, Coronavirus disease 2019 (COVID-19) has shattered the economies and health-care infrastructures worldwide. Even the best of health-care systems (United States, Italy) have been overwhelmed and collapsed because of this unprecedented pandemic. India is preparing itself for the onslaught of Coronavirus. After recording its first case on January 30th, 2020, the rise was slow until the last week of March. However, since then, the number of cases has increased exponentially, and as on April 14th, 2020, there have been more than 10,000 cases of coronavirus disease (COVID-19) in India, which has resulted in more than 350 deaths.

Natriuretic Peptides as a Prognostic Marker for Delirium in Cardiac Surgery-A Pilot Study.

Background and Objectives: Delirium is a common and major complication subsequent to cardiac surgery. Despite scientific efforts, there are no parameters which reliably predict postoperative delirium. In delirium pathology, natriuretic peptides (NPs) interfere with the blood-brain barrier and thus promote delirium. Therefore, we aimed to assess whether NPs may predict postoperative delirium and long-term outcomes. Materials and Methods: To evaluate the predictive value of NPs for delirium we retrospectively analyzed data from a prospective, randomized study for serum levels of atrial natriuretic peptide (ANP) and the precursor of C-type natriuretic peptide (NT-proCNP) in patients undergoing coronary artery bypass grafting (CABG) with or without cardiopulmonary bypass (off-pump coronary bypass grafting; OPCAB). Delirium was assessed by a validated chart-based method. Long-term outcomes were assessed 10 years after surgery by a telephone interview. Results: The overall incidence of delirium in the total cohort was 48% regardless of the surgical approach (CABG vs. OPCAB). Serum ANP levels >64.6 pg/mL predicted delirium with a sensitivity (95% confidence interval) of 100% (75.3-100) and specificity of 42.9% (17.7-71.1). Serum NT-proCNP levels >1.7 pg/mL predicted delirium with a sensitivity (95% confidence interval) of 92.3% (64.0-99.8) and specificity of 42.9% (17.7-71.1). Both NPs could not predict postoperative survival or long-term cognitive decline. Conclusions: We found a positive correlation between delirium and preoperative plasma levels of ANP and NT-proCNP. A well-powered and prospective study might identify NPs as biomarkers indicating the risk of delirium and postoperative cognitive decline in patients at risk for postoperative delirium.

[Biomarkers in cardio-oncology patients]. / Biomarker bei onkokardiologischen Patienten.

In recent decades, major advances in the treatment of malignant diseases have significantly improved long-term survival. However, this has increased the spectrum of side effects of these treatment methods, particularly for the cardiovascular system. Cardiotoxicity can be acute and chronic, including hypertension, heart failure, arrhythmias, acute myocardial infarction, venous thromboembolism, stroke, and valvular heart disease. While the occurrence of cardiotoxicity is known for many older cancer therapies, it needs to be largely evaluated for newer forms of therapy. Diagnosing possible cardiotoxic side effects is essential for optimal treatment, but remains a challenge. Troponin and the natriuretic peptides play an essential role as cardiac biomarkers in the diagnosis of conventional heart diseases. However, they also appear to play an important role in the detection of cardiotoxicity, as well as in the treatment of cardio-oncology patients. Elevated troponin or B-type natriuretic peptide (BNP)/N-terminal pro-B-type natriuretic peptide (NT-proBNP) levels are associated with increased overall mortality and were associated with the development of heart failure in selected cohorts. Troponin can also be used to identify myocarditis associated with immune checkpoint inhibitor therapy. This overview summarizes the current knowledge about biomarkers for the detection of cardiotoxicity due to tumor therapy. Possible clinical recommendations for the detection of cardiotoxic effects using biomarkers are also outlined.

Amniotic Fluid Natriuretic Peptide Levels in Fetuses With Congenital Heart Defects or Arrhythmias.

BACKGROUND: We have previously demonstrated that umbilical cord plasma natriuretic peptide (NP) levels reflect the severity of heart failure (HF) in fetuses with congenital heart defects (CHD). The aim of this study was to evaluate the significance of amniotic fluid (AF) NP levels in the assessment of HF in fetuses with CHD or arrhythmia. Methods and Results: This was a prospective observational study at a tertiary pediatric cardiac center. A total of 95 singletons with CHD or arrhythmia, and 96 controls from 2012 to 2015 were analyzed. AF concentrations of atrial NP (ANP), B-type NP (BNP) and N-terminal pro-B-type NP (NT-proBNP) at birth were compared with ultrasonographic assessment of fetal HF using the cardiovascular profile (CVP) score. Multivariate analysis showed that a CVP score ≤5 and preterm birth are independently associated with high AF NT-proBNP levels. AF NT-proBNP levels of fetuses with CHD or arrhythmia inversely correlated with CVP score (P for trend <0.01). In contrast, AF concentrations of ANP and BNP were extremely low, and it was difficult to assess the degree of fetal HF based on them. CONCLUSIONS: AF NT-proBNP concentrations increase in stepwise fashion with the severity of HF in fetuses with CHD or arrhythmia; it was the optimal NP for assessing the fetal HF.

Evolving Use of Natriuretic Peptides as Part of Strategies for Heart Failure Prevention.

BACKGROUND: Heart failure (HF) remains one of the major cardiovascular challenges to the Western world. Once established, HF is characterized by compromised life expectancy and quality of life with considerable dependence on hospital care for episodic clinical deterioration. Much is understood about the risk factors that predispose to the development of HF. With such a broad range of factors, it is clear that there is a large population at risk, potentially in excess of 25% of the adult population. Therein lies the major challenge at the outset of our efforts to prevent HF. With such a large population at risk, how do we develop an effective prevention strategy? CONTENT: HF prevention requires a multimodal approach. In this review, we focus primarily on the role of natriuretic peptide (NP) as a tool in a prevention strategy. SUMMARY: Prevention of HF is a major public health challenge, underlined by the concerning epidemiological trends, the associated costs, and the continued difficulty to find effective therapies for the growing number of patients with preserved systolic function HF. Population-based approaches focusing on lifestyle and risk factor control have made some impact but not to a satisfactory level and also tend to result in a uniform approach across a population with different risk profiles. Individualizing risk is therefore required, with emerging data indicating that NP-guided risk stratification and intervention can reduce downstream incident HF and other cardiovascular events.

Beyond Natriuretic Peptides for Diagnosis and Management of Heart Failure.

BACKGROUND: Heart failure (HF) is a complex syndrome with an enormous societal burden in terms of cost and morbidity and mortality. Natriuretic peptide (NP) testing is now widely used to support diagnosis, prognostication, and management of patients with HF, but NPs come with limitations, including vulnerability to the presence of obesity, atrial fibrillation, and renal dysfunction, for example. Beyond the NPs, novel biomarkers may supplement traditional clinical and laboratory testing to improve understanding of the complex disease process of HF, and possibly to personalize care for those affected through better individual phenotyping. CONTENT: In this review we discuss novel biomarkers by dividing them into categories based on major pathophysiologic pathways they represent including myocardial stretch/stress, cardiac extracellular matrix remodeling, cardiomyocyte injury/death, oxidative stress, inflammation, neurohumoral activation, and renal dysfunction. SUMMARY: Given the limitations of NPs, along with the complex physiology in HF, it is logical to consider utilization of novel biomarkers providing orthogonal biological and clinical information. Several novel HF biomarkers have shown promise but have substantial expectations to meet before being used clinically. Nonetheless, it is reasonable to expect the future lies in the application of multibiomarker panels for the improvement in management of HF and the personalization of care.

Interpreting Cardiac Biomarkers in the Setting of Chronic Kidney Disease.

BACKGROUND: Chronic kidney disease (CKD) is common, particularly in those of advanced age. Because patients with CKD frequently have cardiac comorbidities and acute or chronic symptoms that may represent heart failure or an acute myocardial infarction (AMI), testing for concentrations of cardiac troponins and natriuretic peptides is frequent. Interpretation of these biomarkers can be challenging when differentiating acute from chronic processes, potentially resulting in missed opportunities to direct appropriate treatment. CONTENT: This review is designed to provide clinicians and laboratorians a platform to understand cardiac specific biomarker interpretation in patients with CKD by summarizing the extensive literature base that has developed specific to this population. First we review the epidemiology and unique contributions of CKD to cardiac pathophysiology. Next we consider the interpretation of cardiac troponin tests for the diagnosis AMI and the prognostic significance of chronic increases across the spectrum of CKD including those requiring renal replacement therapy. Last, we consider the caveats of interpreting natriuretic peptide results for the diagnosis of acute decompensated heart failure in addition to the short- and long-term prognostic implications of increased natriuretic peptide concentrations and CKD in a patient with heart failure. SUMMARY: CKD is common and associated with acceleration of cardiovascular disease. Cardiac biomarker concentrations are often increased even in an absence of symptoms; typically reflecting the extent of underlying cardiovascular disease rather than impairment of renal clearance. Thoughtful interpretation of cardiac biomarkers in those with CKD can continue to provide important diagnostic and prognostic information.

Biochemistry, Therapeutics, and Biomarker Implications of Neprilysin in Cardiorenal Disease.

BACKGROUND: Neprilysin (NEP) is a membrane-bound neutral endopeptidase that degrades a variety of bioactive peptides. The substrates include natriuretic peptides (NPs), which are important regulating mediators for cardiovascular and renal biology. Inhibition of NEP activity and exogenous NP administration thus have emerged as potential therapeutic strategies for treating cardiorenal diseases. More recently, B-type natriuretic peptide (BNP) or N-terminal-proBNP (NT-proBNP), 3'-5' cyclic guanosine monophosphate (cGMP), and soluble NEP as biomarkers have also been investigated in heart failure (HF) trials and their predictive value are beginning to be recognized. CONTENT: The biological functions of NEP and NPs are discussed. Enhancing NPs through NEP inhibition combined with renin-angiotensin-aldosterone system (RAAS) antagonism has proved to be successful in HF treatment, although future surveillance studies will be required. Direct NP enhancement through peptide delivery may have fewer potentially hazardous effects compared to NEP inhibition. Strategies of combined inhibition on NEP with other cardiorenal pathophysiological pathways are promising. Finally, monitoring BNP/NT-proBNP/cGMP concentrations during NEP inhibition treatment may provide supplemental benefits to conventional biomarkers, and the identification of soluble NEP as a novel biomarker for HF needs further investigation. SUMMARY: In this review, the biology of NEP is summarized, with a focus on NP regulation. The degradation of NPs by NEP provides the rationale for NEP inhibition as a strategy for cardiorenal disease treatment. We also describe the current therapeutic strategies of NEP inhibition and NP therapeutics in cardiorenal diseases. Moreover, the discovery of its circulating form, soluble NEP, as a biomarker is also discussed.

Guanylin and uroguanylin are produced by mouse intestinal epithelial cells of columnar and secretory lineage.

Guanylin (GN) and uroguanylin (UGN), through activation of guanylyl cyclase C (GCC), serve to control intestinal fluid homeostasis. Both peptides are produced in the intestinal epithelium, but their cellular origin has not been fully charted. Using quantitative PCR and an improved in situ hybridization technique (RNAscope), we have assessed the expression of GN (Guca2a), UGN (Guca2b), and GCC (Gucy2c) in mouse intestine. In the crypts of Lieberkühn, expression of Guca2a and Guca2b was restricted to cells of secretory lineage, at the crypt's base, and to a region above, previously identified as a common origin of cellular differentiation. In this compartment, comparatively uniform levels of Guca2a and Guca2b expression were observed throughout the length of the gut. In contrast, Guca2a and Guca2b expression in the villus-surface region was more variable, and reflected the distinct, but overlapping expression pattern observed previously. Accordingly, in jejunum and ileum, Guca2a and Guca2b were abundantly expressed by enterocytes, whereas in colon only Guca2a transcript was found in the surface region. In duodenum, only low levels of Guca2b transcript were observed in columnar cells, and Guca2a expression was restricted entirely to cells of the secretory lineage. Gucy2c was shown to be expressed relatively uniformly along the rostrocaudal and crypt-villus axes and was also found in the duodenal glands. Our study reveals novel aspects of the cellular localization of the GCC signaling axis that, apart from its role in the regulation of fluid balance, link it to pH regulation, cell cycle control, and host defense.

Association of cardiovascular emerging risk factors with acute coronary syndrome and stroke: A case-control study.

In this study, we estimated the risk of acute coronary syndrome and stroke associated with several emerging cardiovascular risk factors. This was a case-control study, where an age - and sex-matched acute coronary syndrome group and stroke group were compared with controls. Demographic and clinical data were collected through patient interviews, and blood samples were taken for analysis. In the bivariate analysis, all cardiovascular risk factors analyzed showed as predictors of acute coronary syndrome and stroke, except total cholesterol and smoking. In the multivariate logistic regression model for acute coronary syndrome, hypertension and body mass index, N-terminal section brain natriuretic peptide and pregnancy-associated plasma protein-A were independent predictors. For stroke, the predictors were hypertension, diabetes mellitus, body mass index, and N-terminal section brain natriuretic peptide. Controlling for age, sex, and classical cardiovascular risk factors, N-terminal section brain natriuretic peptide and pregnancy-associated plasma protein-A were independent emerging cardiovascular risk factors for acute coronary syndrome, but pregnancy-associated plasma protein-A was not for stroke. High levels of cardiovascular risk factors in individuals with no episodes of cardiovascular disease requires the implementation of prevention programs, given that at least half of them are modifiable.

Management of chronic heart failure in general practice in Australia.

BACKGROUND: Chronic heart failure is a common clinical syndrome associated with high healthcare system use. OBJECTIVE: The aim of this study was to explore the management of chronic heart failure in Australian general practice. METHODS: Data from the Bettering the Evaluation and Care of Health program were used to determine the prevalence of chronic heart failure, use of natriuretic peptide testing, prescribing patterns, hospitalisation rates and referrals to community-based heart failure management programs in three study periods between 2010 and 2015. RESULTS: Data on 8989 patients from 308 general practitioners were analysed. Of these patients, 324 had chronic heart failure (prevalence 3.6%; 95% confidence interval [CI]: 3.1-4.2), 44% (95% CI: 34.5-53.6) of whom had been hospitalised for the condition. The mean number of prescribed heart failure medication agents was 2.26 (95% CI: 2.13-2.39) per patient. Discharge under community heart failure programs was not routine. DISCUSSION: Chronic heart failure is a significant burden in general practice. Strategies to optimise management and avoid hospitalisation, where possible, are needed.

Is it time for home treatment of pulmonary embolism?

Acute pulmonary embolism (PE) is a frequent cause of death, but not all patients are at high risk of an adverse early outcome. It has been proposed that selected patients may be considered for early discharge and home treatment, but it was only recently that improved risk assessment strategies permitted advances in the identification of low-risk PE. Clinical prediction rules, such as the Pulmonary Embolism Severity Index (PESI), and laboratory biomarkers, particularly natriuretic peptides and cardiac troponins, appeared capable of excluding severe PE and serious comorbidity. Recently, two randomised trials and two prospective cohort studies investigated the feasibility and safety of outpatient treatment. All excluded patients with haemodynamic instability and serious comorbidity, but only one trial used a validated clinical score (PESI) for patient inclusion, and only one cohort study employed a biomarker test. Overall, 90-day outcome was favourable and the results appear promising. To optimise patient selection, future trials will need to test simplified clinical scores combined with high-sensitivity biomarker assays, and it will have to be determined whether echocardiography and/or compression ultrasonography are also required before discharge. Furthermore, ongoing trials will show whether new oral anticoagulants are a safe and cost-effective option for managing patients out of hospital.

Guanylin and functional coupling proteins in the hepatobiliary system of rat and guinea pig.

Guanylin, a bioactive intestinal peptide, is involved in the cystic fibrosis transmembrane conductance (CFTR)-regulated electrolyte/water secretion in various epithelia. In the present work we report on the expression and cellular localization of guanylin and its affiliated signaling and effector proteins, including guanylate cyclase C (Gucy2c), Proteinkinase GII (Pkrg2), CFTR and the solute carrier family 4, anion exchanger, member 2 (Slc4a2) in the hepatobiliary system of rat and guinea pig. Localization studies in the liver and the gallbladder revealed that guanylin is located in the secretory epithelial cells of bile ducts of the liver and of the gallbladder, while Gucy2c, Pkrg2, CFTR, and Slc4a2 are confined exclusively to the apical membrane of the same epithelial cells. Based on these findings, we assume that guanylin is synthesized as an intrinsic peptide in epithelial cells of the hepatobiliary system and released luminally into the hepatic and cystic bile to regulate electrolyte secretion by a paracrine/luminocrine signaling pathway.

Emerging biomarkers in heart failure.

BACKGROUND: Until recently, biomarker testing in heart failure (HF) syndromes has been viewed as an elective supplement to diagnostic evaluation of patients suspected to suffer from this condition. This approach to the use of biomarker testing contrasts with other cardiovascular diagnoses such as acute myocardial infarction, for which biomarkers are integral to disease process definition, risk stratification, and in some cases treatment decision making. CONTENT: In this review we consider various perspectives on the evaluation of biomarkers in HF. In addition, we examine recent advances in the understanding of established biomarkers in HF (such as the natriuretic peptides), the elucidation of novel biomarkers potentially useful for the evaluation and management of patients with HF, and the growing understanding of important and relevant comorbidities in HF. We also review candidate biomarkers from a number of classes: (a) myocyte stretch, (b) myocyte necrosis, (c) systemic inflammation, (d) oxidative stress, (e) extracellular matrix turnover, (f) neurohormones, and (g) biomarkers of extracardiac processes, such as renal function. SUMMARY: Novel applications of established biomarkers of HF as well as elucidation and validation of emerging assays for HF syndromes have collectively led to a growing interest in the more widespread use of such testing in patients affected by the diagnosis.

The rat kidney contains high levels of prouroguanylin (the uroguanylin precursor) but does not express GC-C (the enteric uroguanylin receptor).

The peptide uroguanylin (Ugn) regulates enteric and renal electrolyte transport. Previous studies have shown that Ugn and its receptor GC-C (a ligand-activated guanylate cyclase) are abundant in the intestine. Less is known about Ugn and GC-C expression in the kidney. Here, we identify a 9.4-kDa polypeptide in rat kidney extracts that appears, based on its biochemical and immunological properties, to be authentic prouroguanylin (proUgn). This propeptide is relatively plentiful in the kidney (~16% of intestinal levels), whereas its mRNA is marginally present (<1% of intestinal levels), and free Ugn peptide levels are below detection limits (<0.4% of renal proUgn levels). The paucity of preproUgn-encoding mRNA and free Ugn peptide raises the possibility that the kidney might absorb intact proUgn from plasma, where the concentration of propeptide greatly exceeds that of Ugn. However, immunocytochemical analysis reveals that renal proUgn is found exclusively in distal tubular segments, sites previously shown not to accumulate radiolabeled proUgn after intravascular infusions. Thus proUgn appears to be synthesized within the kidney, but the factors that determine its abundance (rates of transcription, translation, processing, and secretion) must be balanced quite differently than in the gut. Surprisingly, we also find negligible expression of GC-C in the rat kidney, a result confirmed both by RT-PCR and by functional assays that measure Ugn-activated cGMP synthesis. Taken together, these data provide evidence for an intrarenal Ugn system that differs from the well-described intestinal system in its regulatory mechanisms and in the receptor targeted by the peptide.

Gender-specific differences in biomarkers responses to acute coronary syndromes and revascularization procedures.

A growing body of gender-related research in coronary artery disease is beginning to gradually elucidate differences between women and men. In patients presenting with acute coronary syndromes (ACS), these sex differences include varying risk factor profiles, accuracy of diagnostic testing, clinical presentations, treatment practices and outcomes. There is also a differential expression of cardiac biomarkers by sex, which remains unexplained. This paper reviews all the available information on the effect of gender on cardiac biomarkers by search of MEDLINE using the terms gender differences, biomarkers, ACS and revascularization procedures. A better understanding of the sex disparities in biomarkers along with all other clinical information is essential to optimal management and patient care in the future.

Pearls and myths in pleural fluid analysis.

Virtually all patients with a newly discovered pleural effusion should undergo thoracentesis to aid in diagnosis and management. The routine pleural fluid (PF) evaluation usually includes the following: cell count and differential; tests for protein, LDH, glucose, adenosine deaminase, cytology and, if infection is a concern, pH and bacterial and mycobacterial cultures. Distinguishing transudates from exudates with Light's criteria is a pragmatic first step. If the effusion is an exudate, various PF tests have proven diagnostic utility: adenosine deaminase levels >35 IU/L usually indicate tuberculosis in lymphocyte-predominant PF; pH < 7.2 or glucose less than 60 mg/dL allow the clinician to identify complicated parapneumonic effusions; and conventional cytology may reveal malignant cells in 60% of the patients with malignant effusions. A number of optional PF tests may complement the diagnostic approach to an undiagnosed pleural effusion. For example, natriuretic peptide assays significantly improve the accuracy of a diagnosis of cardiac pleural effusion, whereas PF mesothelin levels greater than 20 nmol/L are highly suggestive of mesothelioma.

[Inventory of the use of natriuretic peptides in France]. / État des lieux de l'utilisation des peptides natriurétiques en France.

Since the introduction of routine assay for natriuretic peptides (NP), there is an increasing number of clinical applications for these assays. Due to the continuously increasing number of prescription of those tests, a reappraisal of the use of natriuretic peptide assays, namely BNP and NT-proBNP in France was necessary. This was achieved through a national survey to obtain a detailed description of NP prescription and realization by French laboratories. A questionnaire was sent in April 2010 to hospital and private clinical chemists. Statistical analysis of results concerned 584 answers. This survey demonstrated an equivalent use of BNP and NT-proBNP both in public or private laboratories together with a huge heterogeneity of tests used within labs. Medical prescription heterogeneity both in public or private sectors confirms the large implication of those tests in clinical diagnosis. These assays are not yet standardized, so clinicians and biologists should be very careful when interpreting the results for diagnostic or therapeutic monitoring.