IOPTH Usefulness for Predicting Successful Surgery in Secondary Hyperparathyroidism

USEFULNESS OF IOPTH AS A PREDICTOR FOR SUCCESSFUL PARATHYROIDECTOMY IN SECONDARY HYPERPARATHYROIDISM: A COHORT STUDY

Secondary hyperparathyroidism (SHPT) is a multisystemic syndrome that affects calcium and bone homeostasis in patients with chronic kidney disease (CKD). Despite medical treatment, 1-2% of patients require parathyroidectomy anually. The use of an intraoperative paratohormone protocol (IOPTH) to predict cure still in debate, due to the lack of standardized protocols, the use of different assays and uneven PTH clearance. The aim of this study was to determine the diagnostic accuracy of an IOPTH in patients with SHPT for predicting successful surgery after parathyroidectomy.

A prospective observational study (cohort) was performed in patients who were submitted to parathyroidectomy by an endocrine surgeon for SHPT. All were submitted to a bilateral neck exploration with a subtotal parathyroidectomy. Three IOPTH determinations were withdrawn: at anesthetic induction (PTH0), 15 minutes (PTH15), and 30 minutes (PTH30) after completion gland resection. Another sample was taken 24 hours after the procedure (PTH24), values <150pg/mL defined a successful surgery and patients were assigned to the successful or unsuccessful group. IOPTH drop was analyzed to predict successful surgery with drops of 70% and 90% at 15 and 30 minutes.

Inclusion Criteria:

• PTH >800pg/mL and SHPT symptoms, or
• Asymptomatic patients with PTH >1000pg/mL who were resistant to treatment
• compliance with the signature of the informed consent

Exclusion Criteria:

• patients who respond adequately to medical treatment
• incomplete IOPTH protocol