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

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.

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.

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.

pHPT is associated with increased aortic stiffness, which improves after parathyroidectomy. Our data demonstrate that aortic stiffness may improve upon removal of hyperparathyroid stimuli.