Impaired endothelial function in patients with mild primary hyperparathyroidism improves after parathyroidectomy

Background Primary hyperparathyroidism (PHPT) is associated with cardiovascular morbidity; however, data on the reversibility of cardiovascular disease in mild primary hyperparathyroidism are conflicting. The aim of this study was to assess endothelial function in patients with mild PHPT before and after parathyroidectomy (Ptx). Methods We prospectively evaluated 53 patients with mild PHPT (Group 1; 45 women, eight men; aged 52 +/- 3.1 years) and 46 healthy control subjects (Group 2; 38 women, eight men; aged 46 +/- 9.5 years). Endothelial function was measured as flow-mediated dilation (FMD) and carotid intima-media thickness (CIMT) using Doppler ultrasonography. Patients with diabetes mellitus, coronary heart disease, impaired renal function, hyperthyroidism, hypothyroidism and a history of smoking were excluded from the study. Patients were studied at baseline and 6-12 months after the first evaluation. Results There were no differences with respect to age, gender and BMI between the two groups. Hypertension prevalence was three times higher in group 1 than in controls. % FMD was lower in group 1 than in group 2 (2.6 +/- 1.2 vs 14.8 +/- 9.6, P < 0.001). CIMT was higher in patients with PHPT than controls (0.69 +/- 0.18 vs 0.61 +/- 0.12, P = 0.045). This significance remained when hypertensive patients were excluded from the analysis. While FMD and CIMT improved significantly after Ptx, there were no differences in mild PHPT patients who followed without parathyroidectomy. Conclusion FMD and CIMT are impaired in patients with mild PHPT compared to controls and improved significantly after a successful Ptx. Ptx improves endothelial function in patients with mild PHPT that may lead to decreased cardiovascular morbidity and mortality.