Use of procalcitonin for the diagnosis of pneumonia in patients presenting with a chief complaint of dyspnoea: results from the BACH (Biomarkers in Acute Heart Failure) trial.

AIMS: Biomarkers have proven their ability in the evaluation of cardiopulmonary diseases. We investigated the utility of concentrations of the biomarker procalcitonin (PCT) alone and with clinical variables for the diagnosis of pneumonia in patients presenting to emergency departments (EDs) with a chief complaint of shortness of breath. METHODS AND RESULTS: The BACH trial was a prospective, international, study of 1641 patients presenting to EDs with dyspnoea. Blood samples were analysed for PCT and other biomarkers. Relevant clinical data were also captured. Patient outcomes were assessed at 90 days. The diagnosis of pneumonia was made using strictly validated guidelines. A model using PCT was more accurate [area under the curve (AUC) 72.3%] than any other individual clinical variable for the diagnosis of pneumonia in all patients, in those with obstructive lung disease, and in those with acute heart failure (AHF). Combining physician estimates of the probability of pneumonia with PCT values increased the accuracy to >86% for the diagnosis of pneumonia in all patients. Patients with a diagnosis of AHF and an elevated PCT concentration (>0.21 ng/mL) had a worse outcome if not treated with antibiotics (P = 0.046), while patients with low PCT values (<0.05 ng/mL) had a better outcome if they did not receive antibiotic therapy (P = 0.049). CONCLUSION: Procalcitonin may aid in the diagnosis of pneumonia, particularly in cases with high diagnostic uncertainty. Importantly, PCT may aid in the decision to administer antibiotic therapy to patients presenting with AHF in which clinical uncertainty exists regarding a superimposed bacterial infection.

Increased 90-day mortality in patients with acute heart failure with elevated copeptin: secondary results from the Biomarkers in Acute Heart Failure (BACH) study.

BACKGROUND: In patients with heart failure (HF), increased arginine vasopressin concentrations are associated with more severe disease, making arginine vasopressin an attractive target for therapy. However, AVP is difficult to measure due to its in vitro instability and rapid clearance. Copeptin, the C-terminal segment of preprovasopressin, is a stable and reliable surrogate biomarker for serum arginine vasopressin concentrations. METHODS AND RESULTS: The Biomarkers in Acute Heart Failure (BACH) trial was a 15-center, diagnostic and prognostic study of 1641 patients with acute dyspnea; 557 patients with acute HF were included in this analysis. Copeptin and other biomarker measurements were performed by a core laboratory at the University of Maryland. Patients were followed for up to 90 days after initial evaluation for the primary end point of all-cause mortality, HF-related readmissions, and HF-related emergency department visits. Patients with copeptin concentrations in the highest quartile had increased 90-day mortality (P<0.001; hazard ratio, 3.85). Mortality was significantly increased in patients with elevated copeptin and hyponatremia (P<0.001; hazard ratio, 7.36). Combined end points of mortality, readmissions, and emergency department visits were significantly increased in patients with elevated copeptin. There was no correlation between copeptin and sodium (r=0.047). CONCLUSIONS: This study showed significantly increased 90-day mortality, readmissions, and emergency department visits in patients with elevated copeptin, especially in those with hyponatremia. Copeptin was highly prognostic for 90-day adverse events in patients with acute HF, adding prognostic value to clinical predictors, ser um sodium, and natriuretic peptides. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT00537628.

Mid-region pro-hormone markers for diagnosis and prognosis in acute dyspnea: results from the BACH (Biomarkers in Acute Heart Failure) trial.

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).