Endocrine Abstracts

Background: Clinical and molecular findings have shown that parathyroid hormone (PTH) affects the heart and vasculature through downstream actions of G protein-coupled receptors in the myocardium and endothelial cells. Furthermore, the endothelium is a recognised target tissue of PTH and there is an increasing body of evidence that PTH affects functional and structural properties of arteries. Patients with chronic post-surgical hypoparathyroidism (hypoPT) have higher incidences of hypertension, arterial stiffness and increased risk of mortality.

Purpose: To assess endothelial and other atherosclerotic predictors in subjects affected by hypoPT in comparison with primary hyperparathyroidism (PHPT) and controls.

Methods: In a monocentric, cross-sectional study we enrolled hypoPT patients treated with calcium and calcitriol, PHPT subjects and age-matched controls. All patients underwent a biochemical examination including calcium-phosphorus metabolism, inflammation markers. Moreover, we evaluated brachial artery endothelial function (flow-mediated dilation-FMD), common carotid intima-media thickness (ccIMT), diastolic function and global strain measures with ultrasound.

Results: These are the preliminary results of this project that included 49 subjects (20 hypoPT, 18 PHPT and 11 controls) of 150 expected. All study groups presented similar BMI, TSH and kidney function. HypoPT patients had significantly lower PTH and calcium levels (P<0.001) and higher phosphorus levels (P<0.001) than PHPT and controls. HypoPT had higher inflammation markers (erythrocyte sedimentation rate) levels than PHPT and controls (34.5±17.2 vs 27.6±10.9 vs 15.0±9.6 ml/h,P=0.020). All study groups presented no significant differences in basal brachial artery diameter, FMD and diastolic function. HypoPT showed higher global strain value than PHPT subjects (-19.6±3 vs 17.6±2.5P=0.042), while compared to controls presented similar values. HypoPT showed lower ccIMT than PHPT subjects and higher values than controls (10.0±2.2 vs 11.2±2.4 vs 7.6±2.1 mm,P=0.002).

Conclusion: Up to now, our findings suggest that hypoPT has an increased atherothrombotic risk and needs adequate cardiovascular evaluation. We believe that further comprehensive studies are needed.