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Arterial blood gases (ABG) are obtained commonly in dyspneic persons presenting to emergency departments. The study by Burri and colleagues found that the information contained in ABG fails to distinguish between pulmonary and other causes of dyspnea. On the other hand, arterial pH was highly predictive of ICU admission and outcome. Until large clinical studies show equivalence between peripheral venous and ABG, we will continue to advocate the use of ABG in the evaluation of acute dyspnea.

Objectives: To (1) determine a reference interval for cardiac troponin I (cTnI) using a point-of-care device in normal dogs and compare the results with those published by the manufacturer and (2) determine if cTnI differs among dogs with cardiogenic and noncardiogenic respiratory distress., Design: Prospective observational study., Setting: Emergency and referral veterinary hospital., Animals: Twenty-six clinically normal dogs and 67 dogs in respiratory distress., Interventions: All dogs underwent whole blood sampling for cTnI concentrations., Measurements and Results: Normal dogs had a median cTnI concentration of 0.03 ng/mL (range 0-0.11 ng/mL). Thirty-six dogs were diagnosed with noncardiogenic respiratory distress with a median cTnI concentration of 0.14 ng/mL (range 0.01-4.31 ng/mL). Thirty-one dogs were diagnosed with cardiogenic respiratory distress with a median cTnI concentration of 1.74 ng/mL (range 0.05-17.1 ng/mL). A significant difference between cTnI concentrations in normal dogs and dogs with noncardiogenic respiratory distress was not detected. Significant differences in cTnI concentrations were found between normals versus cardiogenic and cardiogenic versus noncardiogenic respiratory distress groups. Significant differences in cTnI concentrations were identified in > 10 when compared with the < 5 and the 5-10 years of age groups. Receiver operating curve analysis identified cTnI concentrations > 1.5 ng/mL as the optimal "cut-off point" having a sensitivity of 78% and specificity of 51.5%. The area under the receiver operating curve was 0.72. Overall test accuracy was 65%., Conclusions: cTnI concentrations were significantly increased in dogs with cardiogenic respiratory distress versus dogs with noncardiogenic respiratory distress and normal dogs. A significant difference between normal dogs and dogs with noncardiogenic causes of respiratory distress was detected. Although highly sensitive when cTnI concentrations exceed 1.5 ng/mL, the test has low specificity. Assessment of cTnI by the methodology used cannot be recommended as the sole diagnostic modality for evaluating the cause of respiratory distress in dogs., (© Veterinary Emergency and Critical Care Society 2011.)

Background: Difficulty in distinguishing congestive heart failure (HF) from other causes of dyspnoea in the emergency department (ED) may result in delay in appropriate treatment and referral. Although the diagnostic value of serum amino-terminal pro-B-type natriuretic peptide (NT-proBNP) is well documented, the impact on diagnostic certainty of providing these results to ED physicians is not well studied. We sought to determine the effect of providing NT-proBNP results on diagnostic certainty of physicians managing patients presenting to the ED with suspected HF., Methods: A randomized controlled study was conducted in 68 patients presenting to the ED with dyspnoea. ED clinicians initially rated the probability of HF as the cause of dyspnoea without the knowledge of the result. A scale of 1-7 was used, with 1 representing a high degree of certainty of a diagnosis other than HF and 7 representing a high degree of certainty of HF being the cause of dyspnoea. In 38 patients, the ED physician then reassessed the probability of HF as the cause of dyspnoea after receiving the NT-proBNP result. A cardiologist blinded to the NT-proBNP result determined the final diagnosis after review of medical records and investigations., Results: Providing the NT-proBNP result reduced diagnostic uncertainty, defined as a test score of 3-5, from 66% of cases to 18% of cases (P < 0.0001) and improved diagnostic accuracy from 53% to 71% (P = 0.016)., Conclusion: Measurement of NT-proBNP concentrations reduces diagnostic uncertainty and improves diagnostic accuracy in patients presenting to the ED with dyspnoea and possible HF.

Background: The relationship between asymmetric dimethylarginine (ADMA) and symmetric dimethylarginine (SDMA) plasma concentrations and acute heart failure is unknown. We evaluated ADMA and SDMA in patients with acute dyspnea., Methods: We studied 57 dyspneic subjects (50-95 years), with estimated glomerular filtration rate (eGFR) ≥ 30 mL/min/1.73 m², presenting to the emergency department. Troponin I, N terminal-proBNP (NT-proBNP), ADMA, and SDMA were measured. Electrocardiogram, chest X-ray and lung ultrasound were performed. Patients were classified into cardiogenic dyspnea and non-cardiogenic dyspnea, and were also classified on the basis of renal function according to their eGFR., Results: Two-way analysis of variance demonstrated that ADMA and SDMA did not differ for type of dyspnea, but increased in renal dysfunction. NT-proBNP significantly increased both in cardiogenic dyspnea and renal dysfunction. Multiple regression analysis demonstrated that after adjustment for troponin and dyspnea, the only variables which significantly correlated with SDMA plasma concentrations were renal function (β = -0.47, p < 0.001) and NT-proBNP (β = 0.28, p = 0.02)., Conclusions: Neither type of dimethylarginine showed cardiogenic dyspnea to be a determinant for plasma concentrations. Renal dysfunction was a confounder for both ADMA and SDMA.

Objective: To evaluate the effects of noncardiac disease on c-terminal brain natriuretic peptide (cBNP) concentrations in dogs., Design: Prospective observational study., Setting: Urban university veterinary hospital., Animals: Thirty-eight apparently healthy dogs, 28 dogs with cardiac disease (14 CHF, 14 non-CHF), and 81 dogs with primary noncardiac diseases., Interventions: none., Materials and Methods: Plasma was collected from each dog and analyzed for active (cBNP) B-type natriuretic peptide using an assay that is being investigated for commercial use (Biosite)., Measurements and Main Results: Dogs with CHF had significantly higher plasma cBNP concentrations than dogs with subclinical cardiac disease, apparently healthy dogs, or dogs with primary noncardiac disease. However, 21% (28/133) of dogs without CHF (including healthy dogs, dogs with primary noncardiac disease, and dogs with subclinical cardiac disease) had cBNP concentrations above previously identified diagnostic thresholds for CHF, reiterating the importance of reestablishing new diagnostic cutoffs when considering comorbidities affecting B-type natriuretic peptide levels., Conclusions: A clinically relevant proportion of nondyspneic dogs with primary noncardiac diseases have increased cBNP concentrations that exceed previously identified diagnostic thresholds, potentially limiting the ability of this test to identify CHF when noncardiac comorbidities exist. Interpretation of increased cBNP concentrations in such cases must be appropriately interpreted with further diagnostic investigation., (© Veterinary Emergency and Critical Care Society 2011.)

Background: B-type natriuretic peptide (BNP) assay is a useful tool in order to diagnose dyspnea due to congestive heart failure (CHF). On the other hand many other diseases could affect BNP levels. The aim of this study was to investigate a group of elderly patients admitted to an Internal Medicine unit because of dyspnea., Patients and Methods: NT-proBNP was assessed in 132 consecutive patients aged 80±6 years because of dyspnea. History data, anthropometric, clinical and biochemical parameters were collected. Renal function was assessed by the CKD-EPI formula. Diagnosis of pulmonary disease such as infections and chronic obstructive disease was considered and was analyzed as a single parameter. Statistical analysis was carried out dividing patients with high NT-proBNP from those with normal NT-proBNP according to the Januzzi cut-off., Results: NT-proBNP was higher than the normal reference values in 68.7% of patients and its levels increased in the 5 different stages of chronic kidney disease. Subjects with high NT-proBNP had lower haemoglobin levels (11.6±2.1 vs 12.8±1.9 g/dl, p=0.003), higher prevalence of atrial fibrillation (54.3 vs 25%, p=0.001), and lower prevalence of pulmonary diseases (29.7 vs 57.5%, p=0.005). Logistic regression analysis showed that NT-proBNP levels were independently associated with haemoglobin (OR 1.307 95% CI 1.072-1.593, p=0.008) and pulmonary diseases (OR 3.069 95% CI 1.385-6.801, p=0.006)., Conclusions: A disease different from CHF appears to affect NT-proBNP plasma levels. Therefore, determination of its levels does not seem to help clinicians in the definition of dyspnea in elderly people with different comorbidities., (Copyright © 2010 European Federation of Internal Medicine. Published by Elsevier B.V. All rights reserved.)

Background: The use of biomarkers has been demonstrated useful in many acute diseases both for diagnosis, prognosis and risk stratification., Objectives: The purpose of this review is to analyze several biomarkers of potential use in patients referring to Emergency Department with acute dyspnea., State of the Art: The role of natriuretic peptides has a proven utility in the diagnosis, risk stratification, patient management and prediction of outcome in acute and chronic heart failure (HF). New immunoassays are available for the detection of mid-region prohormones in patients with acute dyspnea such as Mid-region pro-adrenomedullin (MR-proADM) and Mid-region pro-atrial natriuretic peptide (MR-proANP). Also procalcitonin, copeptin and D-dimer, which are markers of inflammation, bacterial infections and sepsis, seem to be useful in the differential diagnosis of dyspnea. Conventional and high-sensitivity troponins are fundamental, not only in the diagnosis of acute coronary syndromes, but also as indicators of mortality in patients with acute decompensated heart failure., Perspectives: Further studies with randomized controlled clinical trials will be needed to prove the theoretical clinical advantages offered by a shortness of breath biomarkers in terms of diagnostic, prognostic, cost effective work-up and management of patients with acute dyspnea., Conclusions: A multimarker pannel approach performed by rapid and accurate assays could be useful for emergency physicians to promptly identify different causes of dyspnea thus managing to improve diagnosis, treatment and risk stratification.

Introduction: The diagnostic and prognostic value of arterial blood gas analysis (ABGA) parameters in unselected patients presenting with acute dyspnea to the Emergency Department (ED) is largely unknown., Methods: We performed a post-hoc analysis of two different prospective studies to investigate the diagnostic and prognostic value of ABGA parameters in patients presenting to the ED with acute dyspnea., Results: We enrolled 530 patients (median age 74 years). ABGA parameters were neither useful to distinguish between patients with pulmonary disorders and other causes of dyspnea nor to identify specific disorders responsible for dyspnea. Only in patients with hyperventilation from anxiety disorder, the diagnostic accuracy of pH and hypoxemia rendered valuable with an area under the receiver operating characteristics curve (AUC) of 0.86. Patients in the lowest pH tertile more often required admission to intensive care unit (28% vs 12% in the first tertile, P < 0.001) and had higher in-hospital (14% vs 5%, P = 0.003) and 30-day mortality (17% vs 7%, P = 0.002). Cumulative mortality rate was higher in the first (37%), than in the second (28%), and the third tertile (23%, P = 0.005) during 12 months follow-up. pH at presentation was an independent predictor of 12-month mortality in multivariable Cox proportional hazard analysis both for patients with pulmonary (P = 0.043) and non-pulmonary disorders (P = 0.038)., Conclusions: ABGA parameters provide limited diagnostic value in patients with acute dyspnea, but pH is an independent predictor of 12 months mortality.

Objective: The reduced pressure in aircraft cabins may cause severe hypoxemia and respiratory distress in patients with chronic obstructive pulmonary disease (COPD). The primary objective of this study was to determine the prevalence of in-flight symptoms in COPD patients and non-COPD subjects, and evaluate associations between these symptoms and pre-flight variables., Methods: In a cross-sectional study of 391 COPD patients and 184 non-COPD subjects, we recorded lung function, blood gas values, exercise capacity, air travel habits and in-flight symptoms., Results: Fifty-four percent of the COPD patients had travelled by air the last two years. Hypoxia-related symptoms during air travel were experienced in 25% of the COPD patients and 9% of the non-COPD subjects (p < 0.001). After adjusting for smoking status, age and gender, the odds ratio for COPD patients to experience dyspnea or air hunger was 6.6 (95% CI 2.5-17.3, p < 0.001) compared to non-COPD subjects. In the COPD patients, in-flight dyspnea or air hunger was strongly associated with pre-flight score on the Medical Research Council (MRC) Dyspnea scale (p < 0.001)., Conclusion: COPD patients had significantly increased risk of in-flight dyspnea or air hunger compared to non-COPD subjects. In COPD patients these symptoms were strongly associated with pre-flight MRC Dyspnea score., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Aims: The association of serial NT-proBNP changes and poor quality of life (QOL) with progressive heart failure (HF) and clinical outcomes in emergency department dyspnea patients is poorly understood., Methods and Results: The predictive value of changes in NT-proBNP and QOL (Minnesota Living with Heart Failure scale) from baseline to 30-day follow-up was examined for all-cause 1-year mortality and HF hospitalization. Patients with an initially elevated NT-proBNP (≥300 ng/L) which persisted at 30-days (no ≥25% decrease) were at high risk of death or HF hospitalization (HR=6.36, 95%CI=3.04-13.28). Combined with sustained poor QOL, these subjects with persistently elevated NT-proBNP were at highest mortality risk or HF hospitalization (HR=8.75, 95%CI=3.62-21.16)., Conclusions: Dyspnea patients with elevated NT-proBNP concentrations and no improvement in either NT-proBNP or QOL at 30-days are at high risk of mortality and HF hospitalization. These data highlight the value of serial biomarker measurements combined with serial evaluations for QOL., (Copyright © 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.)

Background: Although numerous biomarkers may be prognostically meaningful in patients with acute dyspnea, few comparative analyses have addressed possible associations between a wide range of candidate biomarkers and clinical variables., Methods: Vital status was obtained for 517 acutely dyspneic patients at 4 years after emergency department presentation. A wide array of biomarkers was measured in this cohort, including natriuretic peptides, necrosis markers, inflammatory markers, hematologic markers, and renal markers. We performed statistical evaluation by using minimization of the Bayesian information criterion to evaluate predictors of 4-year mortality. Cox proportional hazards analysis was used to confirm results from the Bayesian information criterion. A final risk model was derived, and this model was then validated by applying it to patients from a separate cohort of acutely dyspneic patients., Results: By 4 years, there were 186 deaths (36%). In addition to several clinical variables, several biomarkers were significant predictors of death, including log-transformed concentrations of hemoglobin (hazard ratio=0.77; P < 0.001), soluble ST2 (hazard ratio=1.38; P < 0.001), and amino-terminal pro-B-type natriuretic peptide (hazard ratio=1.19; P < 0.001). Risk models that used these significant variables were accurate in predicting 4-year mortality in both the training and validation sets., Conclusions: When added to traditional clinical variables, selected biomarkers added significant value for long-term prognostication in acute dyspnea.

Objectives: The study objective was to investigate the prognostic utility and patient-specific characteristics of ST2 (suppression of tumorigenicity 2), assessed with a novel sensitive assay., Background: Suppression of tumorigenicity 2 signalling has been shown to be associated with death in cardiac and pulmonary diseases., Design/subjects: In an international multicentre cohort design, we prospectively enrolled 1091 patients presenting with acute dyspnoea to the emergency department (ED). ST2 was measured in a blinded fashion using a novel assay and compared to B-type natriuretic peptide (BNP) and NT-proBNP. The primary end-point was mortality within 30 days and 1 year. The prognostic value of ST2 was evaluated in comparison and in addition to BNP and NT-proBNP., Results: Suppression of tumorigenicity 2 concentrations was higher amongst decedents than among survivors (median 85 vs. 43 U mL⁻¹, P < 0.001) and also higher in patients with impaired left ventricular ejection fraction (LVEF) when compared with preserved LVEF (P < 0.001). In receiver operator characteristics analysis, the area under the curve (AUC) for ST2, BNP and NT-proBNP to predict 30-day and 1-year mortality were 0.76, 0.63 and 0.71, and 0.72, 0.71 and 0.73, respectively. The combinations of ST2 with BNP or NT-proBNP improved prediction of mortality provided by BNP or NT-proBNP alone. After multivariable adjustment, ST2 values above the median (50 U mL⁻¹) significantly predicted 1-year mortality (HR 2.3, P < 0.001)., Conclusion: In patients presenting to the ED with acute dyspnoea, ST2 is a strong and independent predictor of 30-day and 1-year mortality and might improve risk stratification already provided by BNP or NT-proBNP., (© 2010 The Association for the Publication of the Journal of Internal Medicine.)

This study evaluated the influence of diabetes on the relationship between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and body mass index (BMI). Simultaneous NT-proBNP and echocardiographic Doppler examinations were performed in 1117 patients with dyspnoea undergoing cardiac catheterization. Patients were divided into BMI > or =25 kg/m2 (obese), 23-25 kg/m2 (overweight) and <23 kg/m2 (non-obese) groups. In the 803 non-diabetic patients, mean plasma NT-proBNP levels in non-obese, overweight and obese patients showed a significant negative correlation with BMI (862.3 +/- 228.8 pg/ml, 611.5 +/- 149.7 pg/ml, 278.3 +/- 172.5 pg/ml, respectively). In the 314 patients with diabetes, there was no correlation between BMI and NT-proBNP. This study demonstrated that obese patients had reduced concentrations of NT-proBNP compared with non-obese patients, despite having higher left ventricular filling pressures. NT-proBNP was not reduced in obese patients with diabetes. These results suggest that factors other than cardiac status impact on NT-proBNP concentration.

Objective: Asthma is a chronic disease involving airway hyperresponsiveness. It was proposed that asthma/chronic shortness of breath elicit chronic systemic inflammation even in the absence of episodic events., Design: Volunteers completed questionnaires relevant to asthma and/or dyspnea and consented to C-reactive protein (CRP) quantitation. Subject groups were: control (no reported dyspnea) and asthma/shortness of breath [dyspnea] group., Setting: Studies were performed in the Saint Louis metropolitan area., Participants: Participants consisted of volunteers aged 18-57. Inclusion criteria were good health, not pregnant, weight > 110 pounds and absence of antiinflammatory medicine use., Results: Serum CRP ranged from undetectable to 22,013 ng/mL. Mean results for asthmatic/dyspnea (n = 22) and control (n = 27) groups were 4,203 +/- 1,323 ng/mL and 1,741 +/- 467 ng/mL (p < 0.05) respectively., Conclusion: Individuals with asthma/asthma-like symptoms have chronic low levels of systemic inflammation despite the absence of episodic pulmonary events. Understanding chronic systemic inflammation relevant to asthma/asthma-like conditions may lead to design of targeted therapeutics.

Objectives: This study aimed to examine the influence of history of heart failure (HF) on circulating levels, diagnostic accuracy and prognostic value of B-type natriuretic peptide (BNP) in patients presenting with all cause dyspnea at the emergency department., Background: BNP has been shown to be very helpful in diagnosis and prognosis of HF. Due to chronically elevated cardiac filling pressures, patients with a history of HF might have higher BNP levels and therefore diagnostic and prognostic properties of BNP may be affected., Methods: We analyzed circulating levels, diagnostic accuracy and prognostic value of BNP in 388 patients without a previous history of HF and compared these to data to 64 patients with a history of HF included in the B-type Natriuretic Peptide for Acute Shortness of Breath Evaluation (BASEL) Study., Results: Baseline BNP levels were higher in patients with a history of HF (median 814 pg/ml [353-1300 pg/ml] vs. 216 pg/ml [45-801 pg/ml], p<0.001). Diagnostic accuracy of BNP to identify HF was comparable in patients with (AUC=0.804; 95% CI 0.628-0.980) and in patients without history of HF (AUC=0.883; 95% CI 0.848-0.919, p=0.389). Prognostic ability of BNP to predict one-year mortality was lower in overall patients with history of HF (AUC=0.458; 95%CI 0.294-0.622) compared to patients without history of HF (AUC=0.710; 95% CI 0.653-0.768, p<0.05)., Conclusions: In patients with history of HF, BNP levels retain diagnostic accuracy. Ability to predict one-year mortality was decreased in unselected patients, but not in patients with acute HF-induced dyspnea., (Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.)

Background: End-tidal carbon dioxide pressure (etCO(2)) is widely used in anaesthesia and critical care in intubated patients. The aim of our preliminary study was to evaluate the feasibility of a simple device to predict capnia in spontaneously breathing patients in an emergency department (ED)., Patients and Methods: This study was a prospective, nonblind study performed in our teaching hospital ED. We included nonintubated patients with dyspnea (> or =18 years) requiring measurement of arterial blood gases, as ordered by the emergency physician in charge. There were no exclusion criteria. End-tidal CO(2) was measured by an easy-to-use device connected to a microstream capnometer, which gave a continuous measurement and graphical display of the etCO(2) level of a patient's exhaled breath., Results: A total of 43 patients (48 measurements) were included, and the majority had pneumonia (n = 12), acute cardiac failure (n = 8), asthma (n = 7), or chronic obstructive pulmonary disease exacerbation (n = 6). Using simple linear regression, the correlation between etCO(2) and Paco(2) was good (R = 0.82). However, 18 measurements (38%) had a difference between etCO(2) and Paco(2) of 10 mm Hg or more. The mean difference between the Paco(2) and etCO(2) levels was 8 mm Hg. Using the Bland and Altman matrix, the limits of agreement were -10 to +26 mm Hg., Conclusion: In our preliminary study, etCO(2) using a microstream method does not seem to accurately predict Paco(2) in patients presenting to an ED for acute dyspnea., (Copyright 2010 Elsevier Inc. All rights reserved.)

Background: The biochemical determination of cardiac natriuretic peptides, primarily brain natriuretic peptide (BNP) and the amino-terminal fragment of its pro-hormone proBNP (NT-proBNP), are reliable tools for diagnosing cardiac disease, establishing prognosis and evaluating the effectiveness of treatment. These biomarkers have proven to be of particular value in the management of chronic and acute heart failure patients, and in the outpatient and the emergency setting., Methods: A multicenter evaluation was performed to assess the practicability, and the analytical and clinical performance of a new point-of-care testing (POCT) PATHFAST NT-proBNP assay. This is an immunochemiluminescent assay using two polyclonal antibodies in a sandwich test format, and performed with a PATHFAST automated analyzer., Results: The limit of detection (mean+3 SD of the signal of 20 replicates of the zero calibrator obtained in one run) was 0.535 ng/L. An imprecision study, performed in accordance with the CLSI protocol, showed coefficients of variation of 4.0%-6.4% (within-run imprecision), 0.0%-3.4% (between-run imprecision), 5.5%-7.2% (between-day imprecision), 7.6%-8.9% (total imprecision). The method was linear to 28,755 ng/L. Slopes and intercepts ranged from 0.89 to 0.90 and from 10.96 to 22.85, respectively when lithium-heparin plasma samples (n=100) were used to compare the assay under evaluation with the routine laboratory methods (Dimension RxL, Stratus CS). When testing matched samples (n=52), a significant difference was found between the 50th percentile NT-proBNP concentration in K(2)EDTA whole blood, K(2)EDTA plasma, lithium-heparin plasma and serum. No significant interference was observed for NT-proBNP in lipemic (tryglicerides up to 28.54 mmol/L), icteric (total and conjugated bilirubin up to 513 and 13 micromol/L, respectively) or hemolyzed (hemoglobin up to 13.50 g/L) samples. The NT-proBNP concentration in a group of 180 healthy donors was significantly influenced by age and gender. In a selected population of patients (n=56) with acute dyspnea admitted to the emergency department, a marked reduction in cardiac natriuretic peptide concentrations was observed in hospitalized patients suffering from heart failure who had a better prognosis compared with those with a poorer prognosis (NT-proBNP mean Delta change, % from -22 to -71 vs. +9 to -11)., Conclusions: The satisfactory analytical and clinical performance of the PATHFAST NT-proBNP assay, together with its excellent practicability, suggests that it would be a reliable tool in clinical practice, in the emergency setting for point-of-care testing, as well as in the central laboratory.

Objectives: Our purpose was to assess the diagnostic utility of mid-regional pro-atrial natriuretic peptide (MR-proANP) for the diagnosis of acute heart failure (AHF) and the prognostic value of mid-regional pro-adrenomedullin (MR-proADM) in patients with AHF., Background: There are some caveats and limitations to natriuretic peptide testing in the acute dyspneic patient., Methods: The BACH (Biomarkers in Acute Heart Failure) trial was a prospective, 15-center, international study of 1,641 patients presenting to the emergency department with dyspnea. A noninferiority test of MR-proANP versus B-type natriuretic peptide (BNP) for diagnosis of AHF and a superiority test of MR-proADM versus BNP for 90-day survival were conducted. Other end points were exploratory., Results: MR-proANP (> or =120 pmol/l) proved noninferior to BNP (> or =100 pg/ml) for the diagnosis of AHF (accuracy difference 0.9%). In tests of secondary diagnostic objectives, MR-proANP levels added to the utility of BNP levels in patients with intermediate BNP values and with obesity but not in renal insufficiency, the elderly, or patients with edema. Using cut-off values from receiver-operating characteristic analysis, the accuracy to predict 90-day survival of heart failure patients was 73% (95% confidence interval: 70% to 77%) for MR-proADM and 62% (95% confidence interval: 58% to 66%) for BNP (difference p < 0.001). In adjusted multivariable Cox regression, MR-proADM, but not BNP, carried independent prognostic value (p < 0.001). Results were consistent using NT-proBNP instead of BNP (p < 0.001). None of the biomarkers was able to predict rehospitalization or visits to the emergency department with clinical relevance., Conclusions: MR-proANP is as useful as BNP for AHF diagnosis in dyspneic patients and may provide additional clinical utility when BNP is difficult to interpret. MR-proADM identifies patients with high 90-day mortality risk and adds prognostic value to BNP. (Biomarkers in Acute Heart Failure [BACH]; NCT00537628)., (Copyright 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

ST2, an IL-1 receptor family member with transmembrane (ST2L) and soluble (sST2) isoforms, was originally described in the context of inflammatory and autoimmune diseases. However, after the identification of IL-33 as the functional ligand for ST2, and conceptualization of the role of ST2/IL-33 signaling in cardiac remodeling, sST2 has emerged as a novel cardiovascular biomarker for the presence of ventricular biomechanical overload. Concentrations of sST2 have been implicated in the presence and severity of heart failure with particular value for prognostication. We will review the use of sST2 as a prognostic marker in heart failure, including present and future directions in this exciting area.

Objective: Brain natriuretic peptide (BNP) is a peptide, which has recently been used in the differential diagnosis and follow-up of patients with heart failure. Our aim in the present prospective and diagnostic designed study is to investigate the role of BNP in determining the etiology of dyspnea and to evaluate its relation with newer echocardiographic parameters., Methods: Thirty-four patients presenting to the emergency department with dyspnea and fulfilling the Framingham criteria for heart failure were included in the study. Blood samples were obtained in the first hour of presentation for measurement of BNP levels from all patients. Detailed transthoracic two-dimensional, Doppler and tissue Doppler echocardiographic studies were then performed within 24 hours of presentation. Statistical analyses were performed using Student's t-test for independent samples, Mann Whitney U test and Pearson or Spearman correlation tests., Results: Plasma BNP levels were found to be significantly correlated with left ventricular end-systolic and end-diastolic diameter, left atrial diameter and the degree of mitral insufficiency (r=0.46, p=0.007; r=0.39, p=0.02; r=0.32, p=0.065; r=0.50, p=0.014, respectively). A significant inverse correlation was observed between plasma BNP levels and left ventricular ejection fraction (r=-0.5, p=0.003). When the patients were grouped according to their BNP levels, the mean ejection fraction of the group with BNP levels below median (578 pg/l) was 60.65+/-13.84%, whereas the mean ejection fraction of the group with BNP levels of 578 pg/l or above (BNP 2) was 49.41+/-15.26% (p=0.027). Out of parameters reflecting left ventricular diastolic functions, only transmitral Epeak/Apeak ratio was found to be significantly associated with BNP levels (r=0.4, p=0.05). Tissue Doppler study revealed significant correlations between BNP levels and right ventricular basal and midsystolic velocities (r=-0.507, p=0.008; r=-0.562, p=0.005, respectively) while none of the left ventricular tissue velocities displayed significant correlation with BNP values., Conclusion: Plasma BNP levels are found to be significantly associated with conventional echocardiographic parameters reflecting left ventricular systolic and diastolic functions and tissue Doppler velocities reflecting right ventricular functions. Our findings are in agreement with the notion that plasma BNP levels are beneficial in the differential diagnosis of patients admitted to emergency service with acute dyspnea.

The present study investigated differences in symptom perception between a clinical sample with medically unexplained symptoms (MUS) and a matched healthy control group. Participants (N = 58, 29 patients) were told that they would inhale different gas mixtures that might induce symptoms. Next, they went through 2 subsequent rebreathing trials consisting of a baseline (60 s room air breathing), a rebreathing phase (150 s, which gradually increased ventilation, PCO2 in the blood, and perceived dyspnea), and a recovery phase (150 s, returning to room air breathing). Breathing behavior was continuously monitored, and dyspnea was rated every 10 s. The within-subject correlations between dyspnea on the one hand and end-tidal CO2 and minute ventilation on the other were used to index the degree to which perceived dyspnea was related to specific relevant respiratory changes. The results showed that perceived symptoms were less strongly related to relevant physiological parameters in MUS patients than in healthy persons, specifically when afferent physiological input was relatively weak. This suggests a stronger role for top-down psychological processes in the symptom perception of patients with MUS.

Introduction: The identification of patients at highest risk for adverse outcome who are presenting with acute dyspnea to the emergency department remains a challenge. This study investigates the prognostic value of Copeptin, the C-terminal part of the vasopressin prohormone alone and combined to N-terminal pro B-type natriuretic peptide (NT-proBNP) in patients with acute dyspnea., Methods: We conducted a prospective, observational cohort study in the emergency department of a university hospital and enrolled 287 patients with acute dyspnea., Results: Copeptin levels were elevated in non-survivors (n = 29) compared to survivors at 30 days (108 pmol/l, interquartile range (IQR) 37 to 197 pmol/l) vs. 18 pmol/l, IQR 7 to 43 pmol/l; P < 0.0001). The areas under the receiver operating characteristic curve (AUC) to predict 30-day mortality were 0.83 (95% confidence interval (CI) 0.76 to 0.90), 0.76 (95% CI 0.67 to 0.84) and 0.63 (95% CI 0.53 to 0.74) for Copeptin, NT-proBNP and BNP, respectively (Copeptin vs. NTproBNP P = 0.21; Copeptin vs. BNP P = 0.002). When adjusted for common cardiovascular risk factors and NT-proBNP, Copeptin was the strongest independent predictor for short-term mortality in all patients (HR 3.88 (1.94 to 7.77); P < 0.001) and especially in patients with acute decompensated heart failure (ADHF) (HR 5.99 (2.55 to 14.07); P < 0.0001). With the inclusion of Copeptin to the adjusted model including NTproBNP, the net reclassification improvement (NRI) was 0.37 (P < 0.001). An additional 30% of those who experienced events were reclassified as high risk, and an additional 26% without events were reclassified as low risk., Conclusions: Copeptin is a new promising prognostic marker for short-term mortality independently and additive to natriuretic peptide levels in patients with acute dyspnea.

Dyspnea is a common symptom, and a heart failure is one of the most important preferred diagnoses of dyspnea. But it is difficult to undergo ECG, US, or other examination to diagnose a heart failure at the patient home, especially in the case of such examination was needed quickly or frequently. Rapidtip BNP and Rapidpia were invented in order to measure BNP rapidly at the patient home, or in the physician's car.

Objective: To determine if serum cardiac troponin I (cTnI) concentrations can distinguish cardiac from non-cardiac causes of respiratory distress (RD) in cats., Animals, Materials and Methods: 53 cats. cTnI concentrations were measured in 30 cats with non-cardiac respiratory distress (RD-NC) and compared to 23 cats with RD due to congestive heart failure (RD+CHF)., Results: The RD+CHF group had higher median cTnI concentration (0.94 ng/ml interquartile range IQR 0.54-4.00, range < 0.20-90.14) than the RD-NC group (< 0.2 ng/ml IQR < 0.2-0.33, range < 0.20-41.1, p<0.001). The area under the curve (AUC) was 0.842 (95% CI 0.728-0.955) for the receiver operator curve (ROC) analysis of the accuracy of cTnI concentrations to discriminate RD+CHF from RD-NC cats. A cut-off of > or = 0.81 ng/ml discriminated RD+CHF from RD-NC cats with a sensitivity and specificity of 65.2% and 90.0% respectively. However considerable overlap in cTnI concentrations between the 2 groups was identified., Conclusions: Serum cTnI concentrations were different in RD+CHF compared to RD-NC cats. However the overlap in cTnI concentrations between the 2 groups reduced the clinical efficacy of the assay which therefore should not be used as a stand-alone test but in combination with other diagnostics such as echocardiography and radiography.

Natriuretic peptides (NPs), particularly B-type natriuretic peptide (BNP) and N-terminal pro BNP (NT-proBNP), are widely used as markers of cardiac wall stress and heart failure (HF) in daily clinical practice. The measurement of NPs became a part of national and international cardiovascular guidelines for the diagnosis and treatment of HF. NP measurement improves diagnosis and management and helps to predict outcome in patients presenting with acute dyspnea in the Emergency Department. Additionally, NPs are of special interest for anesthesiologists. This includes improved management of Intensive Care Unit patients with respiratory failure and preoperative risk assessment. This paper reviews and highlights the use of NPs in clinical practice focusing on issues that may be of particular interest to anesthesiologists.

Background: Uric acid was shown to predict outcome in patients with stable chronic heart failure. Its impact in patients admitted in the Emergency Department with acute dyspnea, however, remains unknown., Methods: We prospectively investigated the diagnostic and prognostic value of uric acid in 743 unselected patients presenting to the Emergency Department with acute dyspnea., Results: Uric acid at admission was higher in patients with acute decompensated heart failure (51% of the cohort) as compared with patients with noncardiac causes of dyspnea (median, 447 micromol/L vs 340 micromol/L, P <.001). The area under the receiver operating characteristic curve for the accuracy to detect acute decompensated heart failure was inferior for uric acid (0.70) than for B-type natriuretic peptide (area under the receiver operating characteristic curve 0.91, P <.001). Patients in the highest uric acid tertile more often required admission to the hospital (92% vs 74% in the first tertile, P <.001) and had higher in-hospital mortality (13% vs 4% in the first tertile, P <.001). Cumulative 24-month mortality rates were 28% in the first, 31% in the second, and 50% in the third tertile (P <.001). After adjustment in multivariable Cox proportional hazard analysis, uric acid predicted 24-month mortality independently of B-type natriuretic peptide (P=.003)., Conclusions: Our study first shows that uric acid, measured at Emergency Department admission or hospital discharge, is a powerful predictor of long-term outcome in dyspneic patients.

Aims: We sought to create a model that adjusts B-type natriuretic peptide (BNP) for specific covariates to better distinguish cardiac from non-cardiac dyspnoea., Methods and Results: HEARD-IT was a multicentre, prospective study of the diagnostic utility of acoustic cardiography in the emergency department. Dyspnoeic patients more than 40 years were eligible. Two cardiologists independently adjudicated the HF outcome. Using logistic regression, a model adjusting BNP for pertinent covariates was developed (n = 740). The mean age was 66 +/- 13 years. Age, gender, ethnicity, body mass index, blood urea nitrogen, and creatinine affected BNP levels independently of HF. The model adjusting BNP for these covariates improved the area under receiver operator characteristic curve for HF compared with BNP alone (0.948, 95% CI 0.934-0.963 vs. 0.937, 95% CI 0.920-0.954; P = 0.004). Net reclassification improvement, a novel metric of model performance, was 3.5% for those without HF (P = 0.05) compared with conventional, unadjusted BNP cut-offs. Thirteen of 116 (11%) patients without HF, but with unadjusted BNP values > or =100 pg/mL, were correctly reclassified as not having HF with the adjusted BNP model., Conclusion: Adjusting BNP for important covariates may improve its ability to distinguish cardiac from non-cardiac dyspnoea.

Hypertension may affect the diagnostic performance of B-type natriuretic peptide (BNP). The objective of the present study was to assess the impact of a history of hypertension or blood pressure elevation on admission on the diagnostic performance of BNP in the diagnosis of heart failure (HF) in patients with acute dyspnea. BNP levels were measured using a rapid point-of-care device in 1,586 patients with acute dyspnea. In patients with HF, BNP levels did not differ between those with and without histories of hypertension. Conversely, in patients without HF, a history of hypertension was associated with higher median BNP levels (38 pg/ml [interquartile range 13 to 119] vs 21 pg/ml [interquartile range 7 to 64], p <0.001). The areas under the receiver-operating characteristic curves were 0.88 and 0.93 for those with and without histories of hypertension, respectively (p <0.001). Blood pressure elevation on admission did not affect the diagnostic accuracy of BNP (areas under the curve 0.90 in the 2 groups). In conclusion, although a history of hypertension is associated with higher BNP levels in patients with acute dyspnea without HF, the impact on the overall diagnostic performance of BNP is modest. Accordingly, BNP performs well as an indicator of HF in patients presenting in emergency departments regardless of a history of hypertension or elevated blood pressure on admission.

Acute dyspnea is one of the leading causes of emergency hospitalization of elderly patients. Clinical diagnostic procedures are difficult in this geriatric population. Acute heart failure is the most frequent cause of acute dyspnea in geriatric patients. The use of plasma B natriuretic peptide (BNP) assays in the general population has profoundly improved its medical management. There has also been progress recently for other frequent causes of dyspnea in the elderly, including infection and venous thromboembolic disease. Procalcitonin assays may be useful as a prognostic factor for infectious disease. Nevertheless, the real value of BNP assays in geriatric populations must be clarified by interventional studies.

Background: Macrophage inhibitory cytokine-1 (MIC-1) has recently been associated with markers of heart function., Aim: This study sought to verify the relationship between markers of heart function (New York Heart Association classification (NYHA)): left ventricle ejection fraction (LVEF), N terminal prohormone of natriuretic peptide B type (NT-proBNP) and MIC-1. Furthermore, the assessment of the usefulness of these markers for differential diagnosis of the myocardial form of dyspnea was explored., Methods: 124 patients (65 women and 59 men) were examined for dyspnea without signs of acute coronary syndrome. All patients underwent echocardiography (calculation of left ventricle ejection fraction-LVEF), and serum NT-proBNP, proguanylin as well as MIC-1 were determined. 21 healthy individuals were defined as the control group., Results and Discussion: Patients were divided into two groups: A--individuals with non-cardiogenic form of dyspnea, n=77 and B--individuals with cardiogenic ethiology of dyspnea, n=47. Significant differences between MIC-1 values in individuals with cardiogenic dyspnea (median 2189.6 ng/L) and non-cardiogenic dyspnea (median 232.1 ng/L) were shown. MIC-1 correlated with age, proguanylin, NT-proBNP and negatively with LVEF (P<0.05). The median values of MIC-1 were closely associated with the NYHA classification (P<0.05). Division of the group under study according to the cause of dyspnea revealed a significant difference in MIC-1 (P<0.01). The cut-off of MIC-1>444.5 ng/L showed 100% sensitivity and 89.3% specificity for diagnosing cardiogenic dyspnea. After adjustment for age, gender and NT-proBNP, MIC-1 levels were significantly associated with the cardiogenic type of dyspnea (P<0.05). We also tested the difference in MIC-1 level among the subgroup with the cardiac form of dyspnea (10 individuals suffered from hypertension and 37 patients had no sign of hypertension). Individuals with and without hypertension had no significant difference in MIC-1 level., Conclusion: MIC-1 is a new diagnostic marker in the differential diagnosis of dyspnea.

Natriuretic peptides (NP) are simple and rapid cardiac biomarkers that quantify hemodynamic cardiac stress and heart failure. Heart failure is a common cause of dyspnea, therefore improvements in the diagnosis of heart failure have a major impact on the diagnosis and management of patients with dyspnea. Four independent randomized controlled studies have confirmed that the additional use of NP in patients with dyspnea improves patient management. Accordingly, measurement of NPs should be part of the work-up in most if not all patients with dyspnea.

Background and Objective: Exertional dyspnoea limits patients with IPF in their activities of daily living. The mechanism, however, has not been elucidated. This study tested the hypothesis in IPF that exertional dyspnoea correlates with cardiopulmonary exercise responses, specifically changes in arterial blood pH and plasma norepinephrine (NE)., Methods: Cardiopulmonary exercise testing with measurements of dyspnoea (Borg scale), plasma NE, plasma lactate and arterial blood gases were performed in 29 patients with IPF and in nine controls., Results: Both groups showed obvious break points in dyspnoea changes during exercise. In IPF, an abrupt change in the Borg scale, pH, PaCO(2) and plasma NE occurred in the late exercise phase after the 'break point'. Compared with controls, patients with IPF had significantly higher HCO(3)(-) levels and physiologic dead space/tidal volume during exercise. In IPF, during both exercise phases, the dyspnoea slope (DeltaBorg scale/Deltaminute ventilation) correlated with the pH slope (DeltapH/Deltaoxygen uptake) (before the break point: r = -0.537, P = 0.0022; r = -0.886, P < 0.0001, after the break point) and the NE slope (DeltaNE/Deltaoxygen uptake) (before the break point: r = 0.481, P = 0.0075; R = 0.784, P < 0.0001, after the break point)., Conclusions: In patients with IPF, exercise-induced acidosis and increases in circulating NE levels were associated with intensity of exertional dyspnoea.

Background: Obesity may reduce diagnostic accuracy of B-type natriuretic peptide (BNP) and affect long-term outcome., Methods: This study evaluated patients included in the BASEL study (N = 452). We compared BNP levels in patients with (n = 86) and without (n = 366) obesity (body mass index <30 and >30 kg/m(2)) and determined sensitivities and specificities of BNP in both patient groups by receiver-operating characteristic analysis. Impact of BNP measurements on patient management and outcome in obesity, as well as 360-day mortality, was assessed., Results: The BNP levels were lower in obese patients (172 pg/mL [interquartile range 31-515] vs 306 [interquartile range 75-1,040]). The optimal BNP cut-point to detect heart failure was 182 pg/mL in obese patients and 298 pg/mL nonobese patients. Obese patients had lower in-hospital mortality (3.5% vs 8.5%, P = .045) and 360-day mortality (15% vs 30%, P = .001). In obese patients, the determination of BNP levels reduced time to initiation of the appropriate treatment (96 +/- 98 vs 176 +/- 230, P < .05) without impacting other end points., Conclusions: Adjustment of BNP values in the assessment of obese patients presenting with acute dyspnea seems necessary to improve diagnostic accuracy and patient management. Obese patients had half the short- and long-term mortality of nonobese patients, independent of their final discharge diagnosis.

Background: ST2, a biomarker of cardiomyocyte stretch, powerfully predicts poor outcomes in patients with acute dyspnea, but nothing is known about associations between soluble ST2 (sST2) and cardiac structure and function, or whether sST2 retains prognostic meaning in the context of such measures., Methods and Results: One hundred thirty-four dyspneic patients with and without decompensated heart failure had echocardiography during index admission and vital status was ascertained at 4 years. Echocardiographic and clinical correlates of sST2 as well as independent predictors of death at 4 years were identified. sST2 correlated with left ventricular end-systolic dimensions/volumes and left ventricular ejection fraction. sST2 was inversely associated with right ventricular fractional area change (rho=-0.18; P=0.046), higher right ventricular systolic pressure (rho=0.26; P=0.005), and right ventricular hypokinesis (P<0.001) and was correlated with tissue Doppler Ea wave peak velocity, but not to other indices of diastolic function. In multivariate regression, independent predictors of sST2 included right ventricular systolic pressure (t=2.29; P=0.002), left ventricular ejection fraction (t=-2.15; P=0.05) and dimensions (end systolic, t=2.57; end diastolic, t=2.98; both P<0.05), amino-terminal pro-B-type natriuretic peptide (t=3.31; P=0.009), heart rate (t=2.59; P=0.01), and presence of jugular venous distension (t=2.00; P=0.05). In a Cox proportional hazards model that included echocardiographic results and other biomarkers, sST2 independently predicted death at 4 years (hazard ratio=2.70; P=0.003)., Conclusions: Among dyspneic patients with and without acute heart failure, sST2 concentrations are associated with prevalent cardiac abnormalities on echocardiography, a more decompensated hemodynamic profile and are associated with long-term mortality, independent of echocardiographic, clinical, or other biochemical markers of risk.

Aims: Previous evaluations of natriuretic peptide (NP) levels in patients with acute dyspnoea presenting to the emergency department (ED) have selected only a minority of patients for echocardiography. We aimed to evaluate the association between NPs and more subtle echocardiographic findings and to assess the potential for NPs to provide additional prognostic information beyond that provided by echocardiography in 'all-comers' with acute dyspnoea., Methods and Results: Prospective echocardiograms were performed on 338/412 patients presenting to the ED with acute dyspnoea. B-type natriuretic peptide and NT-proBNP were measured on presentation. Patients were followed-up for 1 year. Decompensated heart failure was diagnosed in 37% of patients and 13% died. The diagnostic accuracy (c-statistic) of BNP and NT-proBNP for identifying LVEF or= 50%. Natriuretic peptides, but not LV mass or diastolic parameters, independently predicted mortality at 1 year in all patients and in those with an LVEF >or= 50%., Conclusion: In an acute dyspnoea population with 'all-comers' undergoing echocardiography, NPs correlate strongly with structural abnormalities and identify those with preserved LVEF at highest risk for death. Careful interpretation of elevated NP values is needed in the presence of preserved systolic function.

Background: The purpose of this study was to determine the diagnostic power of a newly available assay for amino-terminal pro-brain natriuretic peptide (NT-proBNP) to identify patients with acute heart failure. In addition, the influence of initial NT-proBNP measurements on economic consequences, diagnostic procedures and staff involvement was evaluated., Methods and Results: 401 patients presenting with acute dyspnea or peripheral edema in the emergency department were enrolled. NT-proBNP was measured after initial clinical evaluation. Clinical routine care and diagnostic assessment were blinded to NT-proBNP results. Two cardiologists independently validated the period of hospitalization, clinical examinations and medical therapies of each patient considering NT-proBNP results. The median NT-proBNP level among patients with acute congestive heart failure (CHF) (n=122) was 3497 pg/ml as compared to 320 pg/ml in patients without (n=279) (p<0.0001). An NT-proBNP cutoff level <300 pg/ml was optimal to rule out acute CHF (negative predictive value 96%; sensitivity 96%). NT-proBNP >or=300 pg/ml could strongly predict acute CHF when compared to patients' history or physical examination (odds ratio 9.5; p<0.0001) and diagnostic technical findings (odds ratio 14.7; p<0.05). In patients with NT-proBNP<300 pg/ml, 14% of the period of hospitalization could be saved, corresponding to savings of US $481 per patient. In addition, 9% of the number and time of staff involvement of clinical examinations and therapies could be saved, 10% of the costs of clinical examinations. Chest X-rays were saved in 34%, echocardiography in 9%., Conclusions: Measurement of NT-proBNP leads to multiple saving amounts and optimizes diagnostic pathways and resource allocation.

Objectives: The objective was to determine the incremental benefit of a shortness-of-breath (SOB) point-of-care biomarker panel on the diagnostic accuracy of emergency department (ED) patients presenting with dyspnea., Methods: Adult ED patients at 10 U.S. EDs with SOB were included. The physician's estimates of the pretest clinical probability of heart failure (HF), acute myocardial infarction (MI), and pulmonary embolism (PE) were recorded using deciles (0%-100%). Blood samples were analyzed using a SOB point-of-care biomarker panel (troponin I, myoglobin, creatinine kinase-myocardial band isoenzyme [CK-MB], D-dimer, and B-type natriuretic peptide [BNP]). Thirty-day follow-up for MI, HF, and PE was performed. Data were analyzed using logistic regression and receiver operating characteristics (ROC) curve analysis., Results: Of 301 patients, the mean (+/-standard deviation [SD]) age was 61 (+/-18) years; 56% were female, 58% were white, and 38% were African American. Diagnoses included MI (n = 54), HF (n = 91), and PE (n = 16) in a total of 129 (43%) of the patients. High pretest clinical certainty (>or=80%) identified 60 of these 129 (46.5%) cases. The SOB point-of-care biomarker panel identified 66 additional cases of MI (n = 24), HF (n = 31), and PE (n = 11). The overall adjusted sensitivity for any diagnosis was increased from 65% to 70% with the addition of the SOB point-of-care biomarker panel (difference = 5%, 95% CI = -1.1% to 11%) while specificity was increased from 82% to 83% (difference = 1%, 95% CI = -4% to 7%). The model containing pretest probability and the results of the SOB panel had an area under the curve (AUC) of 83.4% (95% CI = 78.4% to 88.5%), which was not significantly better than the AUC of 80.4% (95% CI = 75.1% to 85.7%) for clinical probability alone., Conclusions: The addition of the SOB panel of markers did not improve the AUC for diagnosing the combined set of clinical conditions. Using the disease-specific SOB biomarkers increased the sensitivity on a disease-by-disease basis; however, specificity was reduced., ((c) 2009 by the Society for Academic Emergency Medicine.)

Background: Circulating plasma N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration facilitates emergency diagnosis of congestive heart failure (CHF) in people. Its utility to discriminate between dyspneic cats with CHF vs. primary respiratory disease requires further assessment. Our objectives were to determine if NT-proBNP (1) differentiates dyspneic cats with CHF vs. primary respiratory disease; (2) increases with renal insufficiency; (3) correlates with left atrial dimension, radiographic cardiomegaly, and estimated left ventricular filling pressure (E/E(a))., Methods: NT-proBNP was measured in 167 dyspneic cats (66 primary respiratory disease, 101 CHF) to evaluate (1) relationship with clinical parameters; (2) ability to distinguish CHF from primary respiratory disease; (3) optimal cut-off values using receiver operating characteristic (ROC) curve analysis., Results: NT-proBNP (1) was higher (median and inter-quartile [25th-75th] percentile) in CHF (754 pmol/L; 437, 1035 pmol/L) vs. primary respiratory disease (76.5 pmol/L; 24, 180 pmol/L) cohorts (P<0.001); (2) positively correlated in CHF cats with increased inter-ventricular septal end-diastolic thickness (rho=0.266; P=0.007) and LV free wall thickness (rho=0.218; P=0.027), but not with radiographic heart size, left atrial size, left ventricular dimensions, E/E(a) ratio, BUN, creatinine, or thyroxine; (3) distinguished dyspneic CHF cats from primary respiratory disease at 265 pmol/L cut-off value with 90.2% sensitivity, 87.9% specificity, 92% positive predictive value, and 85.3% negative predictive value (area under ROC curve, 0.94)., Conclusions: NT-proBNP accurately discriminated CHF from respiratory disease causes of dyspnea.

Background: B-type natriuretic peptide (BNP) and its inactive counterpart NT-proBNP can help to identify or rule out heart failure in patients presenting with acute dyspnoea. It is not well known whether measurement of these peptides can be omitted in certain patient groups., Methods: We conducted a prospective observational study of 221 patients presenting with acute dyspnoea at the emergency department. The attending physicians estimated the probability of heart failure by clinical judgement. NT-proBNP was measured, but not reported. An independent panel made a final diagnosis of all available data including NT-proBNP level and judged whether and how NT-proBNP would have altered patient management., Results: NT-proBNP levels were highest in patients with heart failure, alone or in combination with pulmonary failure. Additive value of NT-proBNP was present in 40 of 221 (18%) of the patients, and it mostly indicated that a more intensive treatment for heart failure would have been needed. Clinical judgement was an independent predictor of additive value of NT-proBNP with a maximum at a clinical probability of heart failure of 36%., Conclusion: NT-proBNP measurement has additive value in a substantial number of patients presenting with acute dyspnoea, but can possibly be omitted in patients with a clinical probability of heart failure of >70%.

Background: Patients presenting with acute dyspnea are often a diagnostic dilemma. A bedside tool that accurately and rapidly identifies increased left ventricular (LV) filling pressure would be helpful. We evaluated acoustic electrocardiography for this purpose., Methods: We pooled 3 cohorts of patients for this analysis. Inclusion criteria required acoustic electrocardiography and echocardiography within 4 hours of each other. Increased LV filling pressure was defined as a pseudonormal or restrictive filling pattern on echocardiography. Area under the receiver operating characteristic curve (AUC) assessed multivariable model accuracy., Results: The median age of the 324 patients was 61 years (range, 19-90 years), 67% were male, and 82% had a history of heart failure. The final multivariable model included mean LV systolic time, S(3) score, maximum negative area of the P wave, and the QTc interval. The AUC was 0.83 (95% confidence interval, 0.78-0.88). Although B-type natriuretic peptide (BNP) was an independent predictor of estimated increased filling pressure when considered alone (odds ratio = 1.002, 95% confidence interval, 1.000-1.003, P = .002), when added to the acoustic model, it did not improve overall model accuracy. In the subset of patients with indeterminate BNP levels (100-500 pg/mL), the acoustic model was more accurate than BNP (AUC = 0.82 vs 0.71)., Conclusions: Bedside acoustic electrocardiography predicted echocardiographic correlates of increased pressures with high accuracy. For patients with an indeterminate BNP level (100-500 pg/mL), the acoustic electrocardiography model was superior to BNP. Prospective model validation is warranted.

Background: The behavior of B-type natriuretic peptide (BNP) is assessed during mechanical ventilation (MV) and spontaneous breathing after extubation in critical patients., Methods: Thirty patients admitted in the Intensive Care Unit (ICU) were enrolled. BNP, fluid balance (FB), airway pressure (AP) and dobutamine infusion needing (DP) were registered in three stages: T0, admission to ICU; T1, before extubation; T2, 24 h after extubation., Results: Patients with congestive heart failure (CHF) had BNP values higher than other patients. The value of BNP during MV was greater than normal in all patients. The cut-off to discriminate patients with heart failure during MV was 286 pgxmL(-1)(sensitivity: 86%; specificity: 90%). The increase of BNP during MV directly correlated with FB and inversely correlated with AP and DP. The plasmatic level of BNP remained higher than normal values 24 h after extubation., Conclusions: The underlying disease of an ICU patient seems to play a relevant role for BNP production and is probably linked to different aspects of therapeutic approach required by the patient. Our data suggest a cut-off value of BNP higher than the usual is necessary to discriminate mechanically-ventilated patients without CHF. This study should be repeated with an enlarged population.