Previous clinical studies have demonstrated that brain natriuretic peptide (BNP) levels correlate with functional capacity via the six minute walk test in patients with idiopathic pulmonary arterial hypertension (PAH). We sought to determine whether BNP levels correlated with six minute walk distance and World Health Organization (WHO) Functional Class in a unique population of patients with connective tissue disease associated- pulmonary arterial hypertension.
A retrospective analysis of 14 patients with connective tissue disease-associated PAH (10 with systemic sclerosis and 4 with mixed connective tissue disease) was undertaken. All patients had a right heart catheterization for diagnostic confirmation. BNP levels, six minute walk distances, and WHO functional classification were extracted from the medical record while patients were receiving therapy with an endothelin antagonist, prostanoid, or a combination thereof. Statistical analysis was performed to determine if BNP levels correlated with six minute walk distance and WHO functional class.
There were 30 data points for BNP verses the six minute walk test. Pearson’s correlation for these variables was -0.574 with a P value of P<0.001. For BNP versus WHO functional classification there were 34 variables. The Pearson’s correlation was 0.586 with a P value of P<0.001 (Table 1).
BNP levels correlate with six minute walk distance and WHO functional class in a population of patients with connective tissue disease-associated PAH.
In patients with pulmonary arterial hypertension secondary to systemic sclerosis or mixed connective tissue disease, BNP may be a useful marker of exercise capacity and functional class. Additional studies with larger sample size are necessary to confirm these findings.
Table 1Test TypeNumber of Data Pointsp ValuePearson CorrelationBNP vs. 6-MWT30P<0.001-0.574BNP vs. WHO34P<0.0010.586
Edward Salerno, None.