One hundred and fourteen consecutive patients with suspected PTE underwent prospective evaluation. Venous blood samples were obtained from an unselected group referred for ventilation–perfusion scintigraphy. B-type natriuretic peptide (BNP), atrial natriuretic peptide (ANP) and N-terminal pro-ANP (N-ANP) were measured by radioimmunoassay using commercially available kits. The scans were classified into three groups according to standard criteria (PIOPED); normal scan (N) (n=20), low/intermediate probability (L/I) of PTE (bcd72e2502f"" title=""Click to view the MathML source"">n=77) and high probability (H) of PTE (n=17). Comparisons were also made between patients with high probability scans who died (n=3) and those who survived (n=14). Values are quoted for the median and interquartile ranges. There were statistically significant differences between groups for levels of (a) BNP (P<0.001): N=6.7 pmol/l (5.6–11.9), L/I=12.5 pmol/l (6.7–28.2) and H=18.5 pmol/l (12.6–74.6); (b) ANP (P<0.005): N=12.6 pmol/l (7.1–16.0), L/I=19.51 pmol/l (12.5–28.2) and H=19.1 pmol/l (15.7–31.7) and (c) N-ANP (P<0.05): N=177 pmol/l (119–200), L/I=302 pmol/l (152–576) and H=322 pmol/l (223–563). Levels of BNP and ANP were significantly (P<0.05) higher in patients with high probability scans and a diagnosis of PTE who died (n=3) than in those who survived (n=14); BNP: 91.6 pmol/l (77.5–336.2) vs. 14.4 pmol/l (11.9–27.4) and ANP 32.5 pmol/l (21.7–105.5) vs. 17.6 pmol/l (15.2–19.3), respectively.
PTE is associated with significantly elevated levels of the natriuretic peptides ANP, BNP and N-ANP. Increasing ventilation–perfusion mismatch on scintigraphy corresponds to incremental increases in the levels of ANP, BNP and N-ANP found. These peptides, and in particular BNP, may add to the diagnosis by rapidly providing a probability of PE before dedicated imaging studies can be performed. Natriuretic peptides require further study to establish their role in identifying a high-risk group who may benefit from early treatments such as thrombolysis.