Persistence of "non-dipping" pattern in blood pressure after curative parathyroidectomy in apparently normotensive patients with symptomatic primary hyperparathyroidism.

BACKGROUND

The prevalence of hypertension in primary hyperparathyroidism (PHPT) varies from 20-80% with data being based on office-based blood pressure measurements. Little is known about ambulatory monitoring of blood pressure (AMBP) in PHPT and changes in blood pressure (BP) variables post-curative parathyroidectomy. Hence, we conducted a prospective study wherein we performed AMBP in apparently normotensive patients with PHPT and reevaluated them 3 months post-curative parathyroidectomy.

METHODS

Consecutive patients with symptomatic PHPT aged 20 years and above underwent 24 hours AMBP at enrollment and at 3 months after successful parathyroidectomy. Pre- and postoperative BP variables were compared and correlated with serum calcium, creatinine and intact parathyroid hormone (iPTH) levels.

RESULTS

After exclusion, 17 symptomatic PHPT patients were enrolled in the study. AMBP detected hypertension in 4 (23.5%) patients. There was a significant reduction in the average nighttime systolic (P=0.007) and diastolic BP (P=0.034) after parathyroidectomy. However, the average 24 hours systolic/diastolic BP, daytime systolic/diastolic BP and average 24 hours mean arterial pressure did not differ before and after surgery. Non-dipping blood pressure pattern was seen in 53% of patients at presentation and persisted in 50% of cases after successful surgery. None of the biochemical parameters significantly correlated with any BP variable.

CONCLUSIONS

AMBP can help detect hypertension in patients with PHPT that remains unrecognized with routine office-based blood pressure measurement. In addition, AMBP detects loss of normal dipping pattern in BP that persists in almost half of the patients even after successful parathyroidectomy, perhaps because of permanent vascular damage induced by PHPT.