No firm association between N-terminal pro-brain natriuretic peptide and percentage of pulmonary vascular obstruction in patients with acute pulmonary embolism.

Abstract Introduction High concentrations of N-terminal-pro-brain natriuretic peptide (NT-proBNP) are found in patients with right ventricular overload. Right ventricular overload may be the result of large perfusion defects in patients with pulmonary embolism (PE). NT-proBNP levels are associated with poorer outcome in patients with acute PE. Likewise, the percentage of pulmonary vascular obstruction (PVO) has shown to be a prognostic parameter for outcome in PE-patients. We postulated that NT-proBNP is associated with the amount of perfusion defects, expressed as the PVO, on perfusion scintigraphy. Methods We included 85 consecutive patients in whom the diagnosis PE was confirmed by ventilation-perfusion scintigraphy. PVO was calculated in all patients. NT-proBNP concentrations were measured at presentation. We plotted the logarithm of NT-proBNP versus the PVO. The strength of the estimated association between NT-proBNP and the PVO was expressed by R2. Results Eighteen percent of the variation in PVO could be explained by NT-proBNP. A positive association becomes apparent for NT-proBNP values above 200 pg/mL, with an increase in PVO of 6.3% (95% Confidence Interval 2.0 to 10.6), with every doubling of NT-proBNP. Conclusion There is an association between NT-proBNP concentrations and PVO, although this relation is quite weak. Some patients with low NT-proBNP values can have a high PVO, which might be relevant for outcome. Therefore, we advise caution in risk stratification and not to focus on NT-proBNP, without involving the clinical condition.