Intraoperative monitoring with second generation assays for parathyroid hormone (PTH) levels "seems to be a valuable tool" in renal hyperparathyroidism (RHPT) surgery, Austrian researchers say.
Klaus Kaczirek and colleagues from the Medical University of Vienna report in the Archives of Surgery that the second generation PTH assay allows "more accurate differentiation between sufficient and insufficient parathyroidectomy" to be achieved than the first generation assay.
This is because the first generation assay incurs an overestimation of whole PTH values, due to cross-reactivity of non-PTH fragments with biologically active PTH (1-84) molecules. It is thought that the second generation assay avoids this problem, and is therefore able to detect incomplete parathyroid resections.
To test this theory, the scientists evaluated the efficacy of the second generation, Bio-Intact PTH assay in 35 patients undergoing primary surgery for RHPT. Twenty-two of the patients were receiving continuous hemodialysis, and the remaining 13 showed persistent autonomous RHPT after kidney grafting.
Total parathyroidectomy was performed on all of the patients. Blood samples were obtained before incision and at 5-minute intervals during surgery and after the last gland had been removed for analysis with the second generation assay.
In the week following surgery, results from the Bio-Intact PTH assay indicated that parathyroidectomy was sufficient in most patients, with the exception of four individuals in the hemodialysis group. Assay results indicated insufficient parathyroidectomy in these patients.
Kaczirek and colleagues conclude: "This preliminary retrospective study documents that Bio-iPTH monitoring seems to be a valuable new tool in surgery for RHPT.
"The common use of an intraoperative, quick Bio-iPTH assay seems mandatory because it might facilitate a more accurate differentiation between sufficient and insufficient parathyroidectomy in RHPT, which is not possible with the commonly used first-generation quick PTH assays."