Carotid vascular abnormalities in primary hyperparathyroidism

Abstract

Context: Data on the presence, extent, and reversibility of cardiovascular disease in primary hyperparathyroidism (PHPT) are conflicting.

Objective: This study evaluated carotid structure and function in PHPT patients compared with population-based controls.

Design: This is a case-control study.

Setting: The study was conducted in a university hospital metabolic bone disease unit.

Participants: Forty-nine men and women with PHPT and 991 controls without PHPT were studied.

Outcome measures: We measured carotid intima-media thickness (IMT), carotid plaque presence and thickness, and carotid stiffness, strain, and distensibility.

Results: IMT, carotid plaque thickness, carotid stiffness, and distensibility were abnormal in PHPT patients, and IMT was higher in patients than controls (0.959 vs. 0.907 mm, P < 0.0001). In PHPT, PTH levels, but not calcium concentration, predicted carotid stiffness (P = 0.04), strain (P = 0.06), and distensibility (P = 0.07). Patients with increased carotid stiffness had significantly higher PTH levels than did those with normal stiffness (141 +/- 48 vs. 94.9 +/- 44 pg/ml, P = 0.002), and odds of abnormal stiffness increased 1.91 (confidence interval = 1.09-3.35; P = 0.024) for every 10 pg/ml increase in PTH, adjusted for age, creatinine, and albumin-corrected calcium.

Conclusions: Mild PHPT is associated with subclinical carotid vascular manifestations. IMT, a predictor of cardiovascular outcomes, is increased. Measures of carotid stiffness are associated with extent of PTH elevation, suggesting that those with more severe PHPT may have impaired vascular compliance and that PTH, rather than calcium, is the mediator.

Figure 1

Comparison of carotid IMT between PHPT (black bar) and control (white bar) subjects. IMT was higher in PHPT than control in all subjects (P < 0.0001), non-Hispanic Caucasian women (P = 0.006), and Hispanic as well as non-Hispanic men (P < 0.0001). Data are presented as mean ± sd adjusted for gender, diabetes, systolic and diastolic blood pressure, triglycerides, and BMI. *, P < 0.01.

Figure 2

PTH levels (picograms per milliliter) are higher in PHPT patients with abnormal (black bar) vs. normal (white bar) stiffness (P = 0.0022) and strain (P = 0.058). Data are presented as mean ± sd.