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

IntroductionHigh 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.MethodsWe 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.ResultsEighteen 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.ConclusionThere 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.