Combination of D-dimer and amino-terminal pro-B-type natriuretic Peptide testing for the evaluation of dyspneic patients with and without acute pulmonary embolism.

CONTEXT: D-dimer concentration can be used to exclude a diagnosis of acute pulmonary embolism. However, clinicians frequently order unnecessary supplemental testing in patients with low concentrations of D-dimer. Elevations in natriuretic peptides have also been described in the setting of pulmonary embolism. OBJECTIVE: We investigated the integrative role of D-dimer with amino-terminal pro-B-type natriuretic peptide for the evaluation of patients with and without acute pulmonary embolism. DESIGN: Patients were selected for analysis from a previous study in which levels of D-dimer and amino-terminal pro-B-type natriuretic peptide were measured. The presence of pulmonary embolism was determined by computed tomographic angiography. RESULTS: The median levels of D-dimer were significantly higher in patients with acute pulmonary embolism. Similarly, the median levels of amino-terminal pro-B-type natriuretic peptide were higher in patients with pulmonary embolism. CONCLUSIONS: The Roche Tina-quant D-Dimer immunoturbidimetric assay provides a high negative predictive value and can be used to exclude acute pulmonary embolism in patients with dyspnea. Measurement of amino-terminal pro-B-type natriuretic peptide in addition to D-dimer improves specificity for acute pulmonary embolism without sacrificing negative predictive value. A combination of both markers may offer reassurance for excluding acute pulmonary embolism, and thus avoid redundant, expensive confirmatory tests.

Amino-terminal pro-brain natriuretic peptide for the diagnosis of acute heart failure in patients with previous obstructive airway disease.

STUDY OBJECTIVE: We evaluate results from amino-terminal pro-brain natriuretic peptide (NT-proBNP) testing with or without those of clinical judgment for the evaluation of dyspneic patients with previous chronic obstructive pulmonary disease or asthma. METHODS: As a secondary analysis of previously collected observational data from a convenience sample of 599 breathless patients, 216 patients with previous chronic obstructive pulmonary disease or asthma who presented to the emergency department were analyzed according to results of NT-proBNP, clinical impression, and their final diagnosis. Test performance of NT-proBNP in these patients with chronic obstructive pulmonary disease or asthma was examined for the group as a whole, as well as in patients with and without previous heart failure. NT-proBNP results were compared to clinician-estimated likelihood for heart failure using receiver operating curves and as a function of NT-proBNP plus clinical evaluation. The final diagnosis was determined by 2 independent cardiologists blinded to NT-proBNP using all available data from the 60-day follow-up period. RESULTS: Overall, 55 patients (25%) had acute heart failure; the median value of NT-proBNP was higher in these patients compared with those without acute heart failure (2,238 vs 178 pg/mL); use of cut points of 450 pg/mL for patients younger than 50 years and 900 pg/mL for patients 50 years or older yielded a sensitivity of 87% (95% confidence interval [CI] 72% to 93%) and a specificity of 84% (95% CI 76% to 88%). In patients without previous heart failure (n=164), median NT-proBNP levels were also higher in patients with heart failure of new onset compared with those with chronic obstructive pulmonary disease or asthma exacerbation (1561 versus 168 pg/mL). High clinical suspicion for acute heart failure (probability >80%) detected only 23% of patients with new-onset heart failure, whereas 82% of these patients had elevated NT-proBNP levels. In patients who had both previous acute heart failure and chronic obstructive pulmonary disease or asthma (n=52), median NT-proBNP levels were significantly higher in those with acute heart failure (4,435 pg/mL) than patients with chronic obstructive pulmonary disease or asthma exacerbation (536 pg/mL). In patients with acute-on-chronic heart failure, NT-proBNP levels were elevated in 91%, whereas clinical impression considered only 39% of cases as high likelihood for acute heart failure. CONCLUSION: NT-proBNP may be a useful adjunct to standard clinical evaluation of dyspneic patients with previous obstructive airway disease.