Studies on flow-mediated vasodilation and intima-media thickness of the brachial artery in patients with primary hyperparathyroidism

The endothelium is a newly recognized target organ of parathyroid hormone ( PTH) and may contribute to its effects on vascular tone and blood pressure regulation. Flow-mediated vasodilation (FMD), brachial and carotid intima-m edia thickness (IMT) were studied in patients with primary hyperparathyroid ism (pHPT) and controls to evaluate endothelial function and structural art erial vessel wall alterations. Sixteen patients with pHPT (mean a SEM, age 44 +/- 5 years; PTH 229 +/- 72 ng/L; serum calcium 3.0 +/- 0.06 mmol/L; ser um phosphate 2.0 +/- 0.2 mg/L) and 16 normocalcemic control subjects matche d for age, sex, and blood pressure were included. Diabetes, hypertension, a nd vascular disease were excluded in both groups. End-diastolic diameter, f low-mediated (FMD) and nitroglycerin-mediated (NMD) dilation of the brachia l artery were measured by a multigate pulsed Doppler system (echo-tracking) . IMT was determined using automatic analysis of the M-line signal. Endothe lium-dependent FMD was impaired in patients compared to controls (4.6 +/- 1 .6% v 19.2 +/- 3.9%, P < .001). NMD (23.8 +/- 3.1% v. 22.4 +/- 2.8%, P = NS ), carotid and brachial IMT (0.60 +/- 0.04 mm v 0.64 +/- 0.06 mm, P = NS, a nd 0.46 +/- 0.04 mm v 0.47 +/- 0.08 mm, P = NS, respectively) and artery di ameters were not different. Endothelium-dependent vasodilation is impaired in patients with primary hyperparathyroidism despite normal IMT. Endothelia l dysfunction may contribute to increased cardiovascular morbidity and mort ality in pHPT. (C) 2000 American Journal of Hypertension, Ltd.