title: Relation of final intraoperative parathyroid hormone level and outcome following parathyroidectomy.
abstract: OBJECTIVE
  To determine if final intraoperative parathyroid hormone (IOPTH) level predicts those at risk for recurrence after parathyroidectomy. Minimally invasive parathyroid exploration guided by preoperative imaging and IOPTH level is an accepted alternative to bilateral exploration for the treatment of primary hyperparathyroidism (HPT). However, additional enlarged, hypercellular parathyroid glands are present in some patients in whom IOPTH levels fall to normal after excision of a single adenoma. At least 15% of patients are normocalcemic with elevated PTH levels (PPTH) after parathyroidectomy. In these patients, a higher risk of recurrent HPT has been found.
  
  
  METHODS
  Retrospective review of medical records.
  
  
  METHODS
  University teaching hospital.
  
  
  METHODS
  The records of all 194 patients who underwent successful initial parathyroidectomy for nonfamilial HPT in 2007 and 2008 by 1 surgeon were reviewed.
  
  
  METHODS
  Intraoperative PTH level was measured prior to incision (baseline); at excision of the abnormal gland; at 5, 10, 15, and 20 minutes after excision; and at various additional times as needed. Of the patients, 71% underwent minimally invasive parathyroid exploration. Calcium, PTH, and 25-hydroxyvitamin D levels were measured during the first month after surgery in all patients and after 3 months or more in 80%. Patients were divided into 5 groups depending on the following final IOPTH levels: lower than 10 pg/mL (group l) (to convert PTH to nanograms per liter, multiply by 1.0); 10 to 19 pg/mL (group 2); 20 to 29 pg/mL (group 3); 30 to 39 pg/mL (group 4); and 40 pg/mL or higher (group 5).
  
  
  RESULTS
  Of the patients, 82% had a single adenoma, 9% had double adenomas, and 9% had 3 or more abnormal glands. The final IOPTH/baseline IOPTH value in groups 1 to 5 was 7%, 11%, 16%, 23%, and 26%, respectively. There was no significant difference in the preoperative calcium among the groups. All 3 patients with persistent HPT and 5 patients with PPTH were in group 5. One of the 96 patients in groups 1 and 2 and 5 of the 72 patients in groups 3 and 4 had PPTH at the last evaluation.
  
  
  CONCLUSIONS
  Patients with a final IOPTH level of 40 pg/mL or higher are at higher risk of having persistent HPT and should be followed up closely and indefinitely following parathyroidectomy.
authors.affiliation: Division of Endocrine Surgery, Department of Surgery, NYU Langone Medical Center, New York, NY 10016, USA. keith.heller@nyumc.org
authors.forename: Keith S
authors.initials: KS
authors.lastname: Heller
authors.forename: Sheila N
authors.initials: SN
authors.lastname: Blumberg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000097:blood; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D049950:Hyperparathyroidism, Primary / Q000097:blood* / Q000175:diagnosis / Q000601:surgery; D007118:Immunoassay; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D010281:Parathyroid Hormone / Q000097:blood*; D016105:Parathyroidectomy / Q000379:methods*; D011379:Prognosis; D012008:Recurrence; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D015415:Biomarkers; D010281:Parathyroid Hormone