The National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Intraoperative Parathyroid Hormone

Ultrafast intraoperative parathyroid hormone monitoring system: prospective, multicentre, clinical validity study

BACKGROUND

Intraoperative parathyroid hormone (PTH) monitoring is a proven and reliable adjunct to parathyroid surgery, able to improve the outcomes and efficiency of the diagnostic and therapeutic pathway for patients with primary hyperparathyroidism. This study evaluated the innovative, compact, fully automated NBCL CONNECT Analyzer, which can measure whole-blood PTH in 5 min.

METHODS

A prospective multicentre study was conducted in stages: results reviews, recommendations, and implementation of improvements to the mechanical design, components of cartridges, calibration, and sampling protocols. Patients undergoing parathyroidectomy had PTH levels measured on the Analyzer and main laboratory platforms, either Roche or Abbott. The Miami criterion of a 50% drop in PTH concentration was used to define biochemical cure during surgery, and normal postoperative calcium level as cure of primary hyperparathyroidism. Measurements on the Analyzer were done by laboratory staff in London and nurses in Stuttgart. The Pearson coefficient (R) and Wilcoxon test were used for statistical analysis.

RESULTS

Some 234 patients (55 male, 179 female) with a median age of 58.5 (age full range 15-88) years underwent parathyroidectomy (195 minimally invasive, 38 bilateral neck exploration, 1 thoracoscopic; 12 conversions) for primary hyperparathyroidism between November 2021 and July 2022. Primary hyperparathyroidism was cured in 225 patients (96.2%). The sensitivity, specificity, and overall accuracy of the Analyzer assay in predicting biochemical cure were 83.9, 100, and 84.8% in phase 1; 91.2, 100, and 91.3% in phase 2; and 98.6, 100, and 98.6% in phase 3. There were no false-positive results (positive predictive value 100%). Correlations between Analyzer measurements and those obtained using the Roche device were very strong (R = 0.98, P < 0.001 in phase 1; R = 0.92, P < 0.001 in phase 2; R = 0.94, P < 0.001 in phase 3), and correlations for Analyzer readings versus those from the Abbott platform were strong (R = 0.82, P < 0.001; R = 0.89, P < 0.001; R = 0.91, P < 0.001). The Analyzer showed continued good mechanical performance, with stable and repeatable operations (calibrations, quality controls). Introducing a stricter sampling protocol and improvements in the clot-detecting system led to a decrease in the number of clotted samples and false-negative results. Outcomes were not affected by measurements performed either by nurses or laboratory staff.

CONCLUSION

Intraoperative PTH monitoring during parathyroid surgery can be done accurately, simply, and quickly in whole blood using the Analyzer.

Impact of intraoperative parathyroid hormone monitoring on the management of patients with primary hyperparathyroidism

BACKGROUND/OBJECTIVE

Intraoperative parathyroid hormone (IOPTH) monitoring during surgery for primary hyperparathyroidism (PHPT) could improve cure rate and simplify current care pathways. This study assesses the performance of US, MIBI and IOPTH monitoring and their impact on outcomes and perioperative strategy.

DESIGN

This is a retrospective study of a prospectively maintained database of patients who underwent parathyroidectomy guided by preoperative US, MIBI and IOPTH monitoring. Test performance (sensitivity, specificity, PPV, NPV, accuracy) and IOPTH added value (percentage of patients in whom test contributed to achieving cure) were calculated.

RESULTS

A total of 617 patients (median age 59 years, 75% females), 603 (97.7%) of them cured, were included in analysis. Sensitivity of US was higher than MIBI (78.2% vs 70%, P < 0.05), but both were inferior to IOPTH (98.6%, P < 0.05). US and MIBI were more sensitive at detecting single gland disease (SGD) than multigland disease (MGD) (85% vs 55% and 77.5% vs 45.5%, respectively, P < 0.05), while IOPTH performed well in both situations (98.8% vs 96.7%, P > 0.05). In 41 patients with incorrect US predictions, MIBI gave correct result only in 12 (29.3%) cases, while IOPTH gave correct predictions in all but one patient (97.6%). Minimally invasive parathyroidectomy (MIP) was completed in 409 patients, with a similar completion rate regardless whether both or one scan was positive. IOPTH added value was significant in whole cohort (14%) and in subgroups of patients with concordant vs discordant scans, minimally invasive vs conventional surgery, and initial vs reoperative surgery.

CONCLUSIONS

Intraoperative parathyroid hormone monitoring is more accurate at predicting cure than US and MIBI are at identifying abnormal glands in patients undergoing parathyroidectomy for PHPT and significantly contributes to cure rate in range of clinical scenarios. This implies that its routine use could facilitate successful surgery in patients with single positive imaging and increase number of MIPs while maintaining high cure rate.

The superiority of minimally invasive parathyroidectomy based on 1650 consecutive patients with primary hyperparathyroidism

OBJECTIVE

To compare the results of minimally invasive parathyroidectomy (MIP) and conventional parathyroid surgery.

BACKGROUND

Primary hyperparathyroidism is a common endocrine disorder often treated by surgical intervention. Outpatient MIP, employing image-directed focused exploration under cervical block anesthesia, has replaced traditional surgical approaches for many patients with primary hyperparathyroidism. This retrospective review of a prospective database compared MIP with conventional parathyroid surgery.

METHODS

One thousand six hundred fifty consecutive patients underwent surgery for primary hyperparathyroidism by a single surgeon between 1990 and 2009 at 2 tertiary care academic hospitals. Conventional bilateral cervical exploration under general anesthesia was performed in 613 patients and MIP was performed in 1037 cases. Cure rates, complication rates, pathologic findings, length of hospital stay, and total hospital costs were compared.

RESULTS

Minimally invasive parathyroidectomy is associated with improvements in the cure rate (99.4%) and the complication rate (1.45%) compared to conventional exploration with a cure rate of 97.1% and a complication rate of 3.10%. In addition, the hospital length of stay and total hospital charges were also improved compared to conventional surgery.

CONCLUSIONS

Minimally invasive parathyroidectomy is a superior technique and should be adopted for the majority of patients with sporadic primary hyperparathyroidism.