S. Liu1, A. Yusufali1, R. Teo1, M. Mao1, Z. F. Khan1, J. C. Farra1, J. I. Lew1 1University Of Miami Leonard M. Miller School Of Medicine,Division Of Endocrine Surgery, DeWitt Daughtry Family Department Of Surgery,Miami, FL, USA
Introduction:
The effect of altered parathormone (PTH) metabolism in renal insufficiency on intraoperative parathormone (ioPTH) monitoring during parathyroidectomy (PTX) for primary hyperparathyroidism (pHPT) remains unclear. A stricter >50% ioPTH drop with return to normal range criterion, rather than the classic >50% ioPTH drop criterion alone, may be needed to achieve optimal operative success in this patient population with renal disease. This study compares operative outcomes using classic and stricter >50% ioPTH drop criteria in patients with mild or moderate renal insufficiency undergoing PTX guided by ioPTH monitoring for pHPT.
Methods:
A retrospective review of prospectively collected data in 605 patients undergoing PTX guided by ioPTH monitoring for pHPT was performed. All patients had elevated calcium and PTH levels, with ≥6 months of follow up and a mean follow up of 45 months. Glomerular filtration rate (GFR) was estimated with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation. The National Kidney Disease Outcomes Quality Initiative (KDIGO) staging was used to define the stages of CKD based on estimated GFR (eGFR): Stage I with normal or high GFR (GFR>90 ml/min), Stage II Mild CKD (GFR= 60-89 ml/min), Stage III Moderate CKD (GFR = 45-59 ml/min). Patients with overt secondary hyperparathyroidism (CKD Stage IV and V) were excluded. Patients were further subdivided into patients with >50% ioPTH drop only criterion (classic) and patients with a >50% ioPTH drop to within normal range (<65 pg/mL) criterion (stricter). Operative outcomes including the rates of operative success, failure, recurrence, bilateral neck exploration (BNE) and multiglandular disease (MGD) were compared across the three CKD groups.
Results:
Of 605 patients, 38% (230/605) had normal renal function or stage I CKD, 44% (268/605) had Stage II CKD, and 18% (107/605) had Stage III CKD. In patients with Stage I and II CKD, there was no statistical differences in rates of operative success, failure, recurrence, BNE and MGD between patients with classic compared to those with the stricter criterion. However, in Stage III CKD patients, there was a significant difference in operative success rates between those patients who had >50% ioPTH drop alone and those who had >50% ioPTH drop and return to normal range, (92% vs. 100%, respectively, p<0.05). There was no difference in recurrence, BNE, or MGD rates in Stage III CKD patients between those who had classic >50% ioPTH drop compared to those with the stricter criterion.
Conclusion:
PTX guided by ioPTH monitoring using the classic >50% ioPTH drop criterion is performed with the highest operative success in patients with normal renal function, Stage I, and Stage II CKD. However, in patients who have Stage III CKD, a stricter >50% ioPTH drop with return to normal range criterion may lead to improved rates of operative success, and should be used during PTX in this patient population with renal disease.