B-type natriuretic peptide in Parkinson's disease: a novel biomarker of dysautonomia

Background: The presence of cardiac diseases in Parkinson’s disease (PD) patients opens the debate on the identification of early biomarkers of heart damage. N-terminal pro-brain natriuretic peptide (NT-proBNP) may be involved in cardiac autonomic denervation. Objectives: i) to investigate whether there is a relationship between NT-proBNP and measures of cardiovascular autonomic function in PD patients; ii) to elucidate the discrimination power of NT-proBNP levels to identify PD patients with dysautonomia. Methods: Thirty-one consecutive PD patients were enrolled. NT-proBNP levels were measured and cardiovascular autonomic function tests were performed, including the Head-up Tilt test (HUTT), Valsalva Maneuver (VM), Hand Grip (HG), and Deep Breathing (DB). ROC curve analysis was performed to explore the discriminatory power of NT-proBNP levels. Non-collinear independent variables associated with autonomic parameters were examined using multivariable linear regression models. Results: we found: i) high levels of NT-proBNP in patients with neurogenic orthostatic hypotension (adj. P = 0.001) and pathologically absent overshoot in VM (adj. P = 0.001) along with significant associations with the difference (Δ) in the HUTT between 10’ values of the systolic and diastolic blood pressure (ΔSBP, ΔDBP) and baseline values (P = 0.011, P = 0.027), ΔBP of the VM phase III (P = 0.024), and the E/I of the DB (P = 0.019); ii) significant correlations with self-reported measures of cardiovascular manifestations; iii) high discriminatory power of NT-proBNP levels in detecting PD patients with dysautonomia (AUC = 0.917, P < 0.0001). Conclusion: This is the first study exploring the relationship between NT-proBNP and cardiovascular autonomic function test measures, suggesting its role as a suitable biomarker of dysautonomia in PD patients.