Cardiac dysfunction in mild primary hyperparathyroidism assessed by radionuclide angiography and echocardiography before and after parathyroidectomy.

Abstract

Primary hyperparathyroidism (PHPT) is associated with increased cardiovascular morbidity for reasons that are incompletely understood. The present study was undertaken to evaluate the effects of parathyroidectomy on cardiac function especially in patients with mild PHPT. METHODS; Fifty patients with mild PHPT (serum calcium, 2.55 to 2.95 mmol/L) were randomized to parathyroidectomy either directly (group A) or after 1 year of observation (group B). Equilibrium radionuclide angiography (ERNA) at rest and at exercise was performed in addition to echocardiography on all patients at inclusion in the study and 1 and 2 years later. Left ventricular mass index was larger (P <.05) in group B compared with group A after 2 years and showed significant correlation to the serum concentration of parathyroid hormone (but not serum calcium) after 1 year. ERNA showed transient subclinical changes in both systolic and diastolic function parameters after parathyroidectomy (decrease of left ventricular ejection fraction and peak filling rate, with return to preoperative levels within 1 year). Combined evaluation by ERNA and echocardiography has shown previously unknown aspects of parathyroid/myocardial interaction, which is consistent with an inotropic influence exerted by parathyroid hormone, and is in favor of early surgical treatment for PHPT irrespective of serum calcium levels.