Diagnostic Accuracy of Intraoperative Intact Parathyroid Hormone Monitoring for Surgical Outcomes of Secondary Hyperparathyroidism

BACKGROUND: Intraoperative intact parathyroid hormone (IO-iPTH) monitoring has not reached a consensus in predicting surgical outcomes of secondary hyperparathyroidism. Here, we explore the predictive effect of IO-iPTH monitoring on surgical outcomes of secondary hyperparathyroidism as a potentially effective standard. MATERIAL/METHODS: We enrolled 119 patients who underwent total parathyroidectomy with autotransplantation from January 2016 to August 2019. Intact parathyroid hormone (iPTH) levels were tested 1 day before surgery (iPTH(pre)), 10 min after glands resection (iPTH(10min)), and 1 and 7 days after the operation (iPTH(d1), iPTH(d7)). According to iPTH(pre) levels, patients were divided into a <2000 pg/ml group and a ≥2000 pg/ml group, and the cutoff values were compared. In patients with successful parathyroidectomy, the value of iPTH(pre) minus iPTH(10min) (iPTH(dec)) and relative-iPTH(10min) were compared between groups. RESULTS: Using cutoff values, the predictive criterion was defined as iPTH(10min) ≤314.5 pg/ml or relative-iPTH(10min) ≤12.4%. In the iPTH(pre) ≥2000 pg/ml group, iPTH(10min) had a higher predictive value (318 pg/ml vs 218 pg/ml) whereas relative-iPTH(10min) had a lower predictive value (12.1% vs 20.3%). In patients with successful PTX, the iPTH(dec) value of the iPTH(pre) ≥2000 pg/ml group was significantly higher than that of the <2000 pg/ml group. Additionally, the relative-iPTH(10min) was significantly lower in the ≥2000 pg/ml group than in the <2000 pg/ml group. CONCLUSIONS: An intraoperative predictive criterion of iPTH(10min) ≤314.5 pg/ml or relative-iPTH(10min) ≤12.4% is associated with effectively predicting surgical success of secondary hyperparathyroidism. The predictive value is affected by iPTH(pre) level; therefore, a variable prediction standard based on iPTH(pre) levels shall be established.