Study objectives: Baseline prognostic assessment in patients with pulmonary hypertension (PH) may help in the selection of treatment. High plasma levels of natriuretic peptide type B have been reported in patients with right ventricular (RV) dysfunction and suggest poor prognosis in patients with idiopathic pulmonary arterial hypertension (IPAH). We prospectively assessed the correlation of N-terminal brain natriuretic peptide (NT-proBNP) with echocardiographic and hemodynamic indexes of RV function as well as with baseline functional status and long-term survival of PH patients.
Patients and design: Fifty-five consecutive patients with a mean (± SD) age of 41 ± 15 years and severe PH (including 36 patients with IPAH) were followed up for up to 36 months. Serum samples for NT-proBNP were secured, and 6-min walk test (6 MWT), RV catheterization, and echocardiography were all performed on the same day, before the introduction of targeted treatment.
Results: The median baseline serum NT-proBNP concentration was 1,674 pg/mL (range, 51 to 10,951 pg/mL). NT-proBNP concentration correlated with 6MWT distance (r = 0.6; p < 0.001), cardiac index, pulmonary vascular resistance, and right atrial pressure (RAP), but not with pulmonary arterial pressure. NT-proBNP levels were also related to the ratio of the diastolic area of the RV and the LV, and to pericardial effusion during echocardiography. Receiver operating characteristic analysis identified ≥ 1,400 pg/mL as the best NT-proBNP threshold predicting fatal outcome for the entire study group as well as for IPAH patients (sensitivity, 88% and 100%, respectively; specificity, 53% and 56%, respectively). In multivariate analysis, NT-proBNP, troponin T, and RAP were identified as independent factors for poor prognosis for the entire study group, while only NT-proBNP and RAP were identified as markers for poor prognosis in the IPAH subgroup.
Conclusions: NT-proBNP level is related to the right heart morphology and dysfunction in PH patients. A serum NT-proBNP level of ≥ 1,400 pg/mL was found to be useful in identifying patients with poor long-term prognosis both in the whole studied group and in the IPAH subgroup.