Increased plasma N-terminal pro-B-type natriuretic peptide and markers of inflammation related to atherosclerosis in patients with primary hyperparathyroidism.

OBJECTIVE: Increased risk of cardiovascular disease has been reported in patients with primary hyperparathyroidism (PHPT). The aim of this study was to evaluate novel plasma risk markers of cardiovascular disease in patients with PHPT. DESIGN: PHPT patients were evaluated with a control group. Patients who underwent parathyroidectomy were re-evaluated after 7 and 18 months. PATIENTS: Forty-five PHPT patients and 40 matched controls participated. Seventeen patients underwent parathyroidectomy. MEASUREMENTS: Plasma N-terminal pro-B-type natriuretic peptide (NT-proBNP), high-sensitivity C-reactive protein (CRP), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha), lipids and blood pressure were measured. In 27 patients a bicycle exercise test and radionuclide angiography were performed, and repeated in those who underwent parathyroidectomy. RESULTS: Plasma NT-proBNP, CRP and TNF-alpha, but not IL-6, were higher in patients with PHPT than in controls (P < 0.01 and P = 0.17, respectively). In patients with PHPT, NT-proBNP correlated with systolic blood pressure, left ventricular end-diastolic volume, and peak oxygen uptake (all P < 0.01). Log CRP correlated with systolic and diastolic blood pressure (both P < 0.05) and log IL-6 (P < 0.01). No significant correlations were observed between PTH or calcium and risk markers of cardiovascular disease. No decrease in NT-proBNP, markers of inflammation or blood pressure was observed after parathyroidectomy. CONCLUSIONS: Our data suggest that hypertension or other factors, rather than plasma calcium or PTH, could explain the increased levels of the inflammatory markers and NT-proBNP in PHPT. We therefore suggest that aggressive treatment of hypertension should be initiated in patients with PHPT to try to reduce the increased cardiovascular mortality described in PHPT. Further prospective studies are needed to validate the suggestion that increased levels of NT-proBNP and inflammatory markers also represent strong prognostic markers of cardiovascular disease in patients with PHPT.