Do Intraoperative Total Serum and Ionized Calcium Levels, Like Intraoperative Intact PTH Levels, Correlate with Cure of Hyperparathyroidism?

Abstract

Intraoperative parathyroid hormone (ioPTH) monitoring is useful in the operative management of hyperparathyroidism. Measurement of intraoperative total serum calcium (TSC) and ionized calcium (ICa) levels may be less expensive and more readily available methods of intraoperative guidance during neck dissection than ioPTH levels, the gold standard. We compared the accuracy of monitoring intraoperative TSC and ICa to that of ioPTH for predicting surgical cure during parathyroidectomy. Over a 10-month period, 47 parathyroidectomies were performed, during which ioPTH, TSC, and ICa were measured. Samples were obtained at the start of the operation and 5 and 10 minutes after gland removal. Data were compared and trends analyzed with respect to removal of abnormal parathyroid tissue as confirmed by pathology. The Wilcoxon signed rank test was used to determine if decreases in TSC and ICa were significant. The mean baseline ioPTH level (253 +/- 247 pg/ml) dropped by 70% at 5 minutes after removal of the abnormal glands (68 +/- 85 pg/ml) and by 83% at 10 minutes (32 +/- 25 pg/ml). The mean baseline TSC level (10.1 +/- 0.9 mg/dl) dropped by 4% at 5 minutes after removal of the abnormal glands (9.7 +/- 0.8 mg/dl) and remained at 4% at 10 minutes (9.6 +/- 0.7 mg/dl). The mean baseline ICa level (1.4 +/- 0.1 mmol/dl) also dropped by 4% at 5 minutes after removal of the abnormal glands (1.3 +/- 0.1 mmol/dl) and remained at 4% at 10 minutes (1.3 +/- 0.1 mg/dl). ioPTH dropped by > or = 50% in 39 patients (83%) at 5 minutes and in 46 patients (98%) at 10 minutes after gland resection. TSC decreased below baseline at 5 minutes and remained below baseline at 10 minutes in only 37 patients (79%). In the remaining 21% of patients, TSC decreased inconsistently, if at all, with respect to baseline at both the 5- and 10-minute time points. ICa decreased below baseline at 5 minutes and remained below baseline at 10 minutes in only 35 patients (77%). In the remaining 23% of patients, ICa, like TSC, changed inconsistently at 5 and 10 minutes after parathyroidectomy with respect to baseline levels. Decreases in TSC and ICa during parathyroidectomy, if present, are thus minimal. Unlike ioPTH levels, TSC and ICa levels do not consistently decrease at 5 and 10 minutes after gland resection. Although inexpensive and readily available, monitoring the intraoperative TSC and ICa is not clinically reliable for confirming removal of hyperfunctioning parathyroid glands.

Intraoperative calcium monitoring is insufficient to predict the surgical success of parathyroidectomy for primary hyperparathyroidism

“…Interestingly, even in the study by Quiros et al, a distinct drop of tCa 5 and 10 min after resection was detected in 59% of patients, while 16% had an increase of tCa, with no or even fl uctuating changes of tCa 5 and 10 min after the PTX in the remaining patients. 9 Up to now, these inconsistent results of the previously published studies have remained unexplained.…”

“…Quiros et al documented a marginal but detectable reduction of intraoperative tCa and iCa levels in two studies. 8,9 Nevertheless, both parameters proved insuffi cient for intraoperative monitoring of a PTX. Interestingly, even in the study by Quiros et al, a distinct drop of tCa 5 and 10 min after resection was detected in 59% of patients, while 16% had an increase of tCa, with no or even fl uctuating changes of tCa 5 and 10 min after the PTX in the remaining patients.…”

“…A short-term disturbance of this C-PTH/iPTH ratio after a parathyroidectomy could account for the different responses of individual patients in serum calcium levels after a parathyroidectomy, as reported in this study and by others. 8,9 Consequently, a short-acting functional link at least between iCa and PTH fragments seems possible. In conclusion, the current results clarify the confl icting reports about the utility of calcium for intraoperative monitoring of PTX for pHPT in the literature, and indicate that calcium is insuffi cient as a surrogate marker for iPTH monitoring during a parathyroidectomy.…”

“…While some studies reported a signifi cant intraoperative decrease of mean total serum calcium (tCa) during parathyroidectomy (PTX) and concomitant cure in 100% of patients, 7 others detected only minor changes or even an increase of tCa and ionized serum calcium (iCa) after PTX. 8,9 In this prospective study, we compared the intraoperative changes of serum calcium with simultaneously measured levels of intact parathyroid hormone during conventional PTX in patients with sporadic pHPT. The objective was to evaluate the effi cacy and accuracy of both markers for intraoperative monitoring during a parathyroidectomy.…”

Significance of Monitoring Bio-Intact PTH (1–84) During Parathyroidectomy for Secondary Hyperparathyroidism

“…Therefore, the decline in PTH level after removal of every hyperfunctioning parathyroid gland is differs. Moreover, since currently available intraoperative first-generation intact PTH assays measure both PTH (1-84) and non-PTH (1-84) fragments that are present in significant concentrations in the blood of uremic patients, intraoperative first-generation intact PTH monitoring cannot be used to determine whether resection of hyperfunctioning parathyroid tissue in patients with secondary HPT has been insufficient [15][16][17][18][19][20].…”