NT-proBNP promising biomarker for SSc-PAH
medwireNews: N-terminal pro-B-type natriuretic peptide (NT-proBNP) may be more accurate than BNP for detecting and monitoring pulmonary arterial hypertension (PAH) in patients with systemic sclerosis (SSc), study findings suggest.
However, Lorinda Chung (Stanford University, California, USA) and co-researchers stress that more research is still needed “to better compare the utility of these two natriuretic peptides in clinical practice.”
The participating SSc patients, drawn from the multicenter prospective PHAROS cohort, included 172 with confirmed pulmonary hypertension (PH) and 157 considered at risk for PAH, due to an increased right ventricular systolic pressure, a reduced diffusion capacity of carbon monoxide (DLCO) with a preserved forced vital capacity (FVC), or an increased ratio of %FVC to %DLCO. Of this latter group, 26 developed PH during a median follow-up of 3.5 years, with 16 developing PAH.
The team reports in Clinical and Experimental Rheumatology that NT-proBNP and BNP levels were both significantly higher in SSc-PH patients than in the at-risk group, at 503 versus 82 pg/mL and 135 versus 43.5 pg/mL, respectively.
However, of the two biomarkers, NT-proBNP was more closely associated with hemodynamic variables including mean pulmonary arterial pressure, pulmonary vascular resistance, and cardiac output. And although elevated levels of NT-proBNP (≥210 pg/mL) and BNP (≥64 pg/mL) had equivalent sensitivity for the presence of PAH, at a respective 73% and 71%, the former was more specific, at 78% versus 59%.
But neither baseline levels nor longitudinal changes of the biomarkers predicted which at-risk patients would develop PAH, even after combining the two biomarkers and adjusting for use of calcium channel blockers. Beyond hemodynamic variables, only creatinine was associated significantly with risk for SSc-PAH and marginally with risk for SSc-PH.
The individual biomarkers also failed to predict the risk for death – 14 at-risk patients and 30 with confirmed PH died during follow-up – but patients with BNP levels of at least 180 pg/mL and NT-proBNP of at least 553 pg/mL had a significant 3.8-fold increased mortality risk.
The researchers also note that the relatively low number of deaths and progressions to PAH among at-risk patients may have limited their ability to detect significant associations.
By Eleanor McDermid
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