MON-839 - Coronary Artery Calcium Score in Patients with Primary Hyperparathyroidism: A Cross-Sectional Study

Introduction
Primary hyperparathyroidism (PHPT) is a common endocrine disease characterized by increased levels of parathyroid hormone (PTH) causing hypercalcemia. The most common cause of PHPT is sporadic due to an adenoma in one of the parathyroid glands. PTH has been recognized as a hormone with possible effects on the cardiovascular system. However, studies investigating coronary artery calcium score (CACS) in patients with PHPT have shown conflicting results. Hence, we aimed to examine the risk of cardiovascular disease in patients with PHPT.

Materials and methods
Preliminary data from a cross-sectional study on 50 patients with PHPT compared to 50 randomly selected people from the general population. All participants underwent measurement of pulse wave velocity (PWV) using an applanation tonometer (AtCor Sphygmocor Xcel), office blood pressure (BP), blood sampling and coronary computed tomography angiography (CCTA).

Results
Seventy-four individuals have consented to participate in the study (24 patients with PHPT and 50 controls). Patients and controls had a similar mean age±SD of 64±7.6 and 59±11.9 years, respectively (p=0.08). There was no significant difference between the sex of PHPT patients and controls (p=0.74). Cardiovascular risk factors, including smoking and diabetes, did not differ significantly between groups (p=0.48, p=0.1). Similarly, the proportions of participants receiving lipid-lowering agents or antihypertensive treatment were comparable (p=0.275, p=0.9). Among patients with PHPT, 37.5% had moderate to severe hypercalcemia defined as an ionized plasma calcium ≥ 1.45 mmol/L (reference interval 1.18-1.32 mmol/L).
Mean low density lipoprotein (LDL)-cholesterol levels did not differ between groups (p=0.36), but patients with PHPT had lower levels of high density lipoprotein (HDL)-cholesterol compared with controls (1.42 mmol/L versus 1.68 mmol/L; p=0.008). Patients with PHPT had higher office BP compared to controls (136/84 vs 128/75 mmHg; psystolic=0.06, pdiastolic =0.001), however, mean pulse wave velocity did not differ between groups (PHPT: 9.22 ; 95% confidence interval [95% CI], 8.55; 9.88 m/s versus controls: 9.01; 95% CI, 8.57; 9.45 m/s; p=0.58).
The proportion of PHPT patients with one or more plaques present in the coronary arteries was 46% (95% CI, 26;67) versus 42% (95% CI, 28;57) in the controls (p = 0.76). Neither did PHPT patients have more obstructive disease compared to controls (p=1.0). Severity of PHPT (mild versus moderate-severe hypercalcemia) did not affect the presence of plaques in patients with PHPT (p=0.68). Additionally, the proportion of participants with CACS ≥ 1 was similar in both the PHPT and control group (p=0.89).

Conclusions
Preliminary findings indicate that patients with PHPT have higher office BP but no increase in coronary plaque burden on CCTA.

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