Study objectives: Primary pulmonary hypertension (PPH)
is a rare disease of unknown etiology that is characterized by a poor
prognosis. This study was undertaken to investigate possible
correlations between endothelin (ET)-1 and big ET-1 plasma levels and
the severity of PPH.
Patients: Sixteen consecutive
patients with PPH were included.
Hemodynamics of patients with PPH were measured by right-heart
catheterization, and a 6-min walk test was performed.
Measurements: Plasma levels of the biologically active
peptide ET-1 and its precursor big ET-1 were determined in blood
samples from the pulmonary artery, peripheral artery, and peripheral
vein by radioimmunoassay.
Results: A strong
correlation was shown between pulmonary vascular resistance, mean
pulmonary artery pressure, cardiac output, cardiac index, 6-min walk
data, and elevated plasma levels of big ET-1 as well as mature ET-1
plasma levels at all sites of blood sampling (p < 0.01 and
p < 0.05, respectively).
Conclusions: Levels of
circulating ET-1 might become a prognostic marker for patients with PPH
and serve as a tool for the selection of patients who may benefit from
treatment with ET-receptor antagonists.