Diagnostic Values of Intraoperative (1-84) PTH Levels are Superior to iPTH for Successful PTX in CKD Patients.

PURPOSE Persistent secondary hyperparathyroidism (SHPT) may occur because of residual cervico-thoracic parathyroids in parathyroidectomy (PTX) patients with chronic kidney disease (CKD). We compared the predictive values of intraoperative plasma (1-84) parathyroid hormone ([1-84]PTH) and intact PTH( iPTH) levels in order to improve the safety and efficiency for PTX prospectively. METHODS We included 100 healthy controls, 162 stage 5 CKD patients without SHPT, 214 PTX patients because of SHPT. Plasma iPTH and (1-84)PTH levels were measured before incision (io-iPTH0, io-[1-84]PTH0), 10min (io-iPTH10, io-[1-84]PTH10) and 20min (io-iPTH20, io-[1-84]PTH20) after removing all parathyroids. Reduction percentage of PTH at 10min and 20min were calculated (io-iPTH10%, io-[1-84]PTH10%, io-iPTH20%, io-[1-84]PTH20%). IPTH and (1-84)PTH were measured by the second and third-generation PTH assay respectively. RESULTS Median baseline (1-84)PTH levels in controls, non-PTX and PTX patients were 22.1(15.4-31.3)pg/ml, 94.5(52.3-190.7)pg/ml and 850.9(595.0-1269.0)pg/ml. Compared with controls and non-PTX patients, PTX group had more obvious mineral metabolism disorders. There were 187 successful PTX, 19 persistent SHPT patients, and 8 patients were lost to follow-up. Receiver operating characteristic (ROC) curves revealed io-(1-84)PTH10%＞86.6% (area under the curve [AUC] 0.77, sensitivity 55.1%, specificity 94.7%), and io-(1-84)PTH20%＞87.5% (AUC 0.92, sensitivity 84.0%, specificity 94.7%) could suggest successful PTX. Sensitivity of io-iPTH20% and io-(1-84)PTH20% were higher than those at the time-point of 10min. Moreover, the specificity, sensitivity of (1-84)PTH reduction percentage were superior to iPTH. CONCLUSION Intraoperative reduction percentages of plasma (1-84)PTH levels are superior to iPTH for accurately predicting successful PTX, especially at the time-point of 20min after all cervico-thoracic parathyroids are resected.