Large-artery stiffness: a reversible marker of cardiovascular risk in primary hyperparathyroidism.

OBJECTIVE: Patients with primary hyperparathyroidism (pHPT) are at increased risk of cardiovascular mortality. We investigated whether aortic stiffness, an early marker of arteriosclerosis and a strong predictor of cardiovascular risk, is increased in pHPT, and whether it improves after parathyroidectomy.
METHODS: Twenty-four patients with mild pHPT (age 56 ± 10 years, blood pressure 136/85 mmHg, serum calcium 2.55-3.00 mmol/L) and 48 control subjects individually matched with cases by age, sex and blood pressure underwent aortic (carotid-femoral) and upper-limb (carotid-radial) pulse wave velocity (PWV) determination by applanation tonometry in a case-control study. Subjects with renal disease, diabetes, treated hypertension or overt cardiovascular disease were excluded from the study. Seventeen of the patients with pHPT were re-examined 4 weeks after surgical parathyroidectomy.
RESULTS: Aortic PWV was significantly higher among pHTP patients (11.4 ± 2 vs 9.6 ± 2 m/s, p<0.001). In a conditional logistic regression analysis, pHPT was independently associated with an increased risk of having an aortic PWV >12 m/s (odds ratio 3.28, 95% confidence interval 1.21-8.93). As expected, surgery was accompanied by a reduction in serum calcium (from 2.77 ± 0.2 to 2.25 ± 0.1 mmol/L, p<0.001) and parathyroid hormone (from 29.6 ± 10 to 3.3 ± 2 pmol/L, p<0.001). Aortic PWV decreased after surgery (from 10.9 ± 2 to 9.8 ± 2 m/s, p=0.003). The change in aortic PWV remained significant also after adjustment for changes in blood pressure (p<0.01). Changes in upper-limb PWV generally paralleled those in aortic PWV.
CONCLUSION: pHPT is associated with increased aortic stiffness, which improves after parathyroidectomy. Our data demonstrate that aortic stiffness may improve upon removal of hyperparathyroid stimuli.