Comparison of ICG-angiography and chromography for the prevention of postoperative hypoparathyroidism

Purpose of study. Evaluation of the efficacy of angiography with indocyanine green and chromography as methods to identify and preserve parathyroid glands (PRGs). Identification of the main predictors of the hypoparathyroidism development. Material and methods. A single-center prospective randomized controlled study was performed on the basis of the thoracoabdominal surgery department of FSBI A.M. Nikiforov All-Russian Center for Emergency and Radiation Medicine of the Emergency Situations Ministry of Russia in the period from 2018 to 2024. A total of 162 patients were included in the study and were randomized into 3 groups: 1 – with intraoperative angiography (n=29), 2 – receiving chromography (n=59), control group (n=74). All patients were preoperatively tested for parathormone and total calcium levels, and the groups were tested for comparability of baseline data. In the postoperative period, laboratory values were reassessed and compared. Risk factors for postoperative hypoparathyroidism such as volume of surgery, diagnosis, recurrent thyroid surgery and decreased preoperative ionized calcium concentration were also assessed in each group. Statistical analyses were performed using Microsoft Excel 10.0 data analysis package. Results. Total serum calcium levels in the pre- and postoperative periods were (mmol/L): 2.38±0.14 and 2.31±0.17 in group 1, 2.39±0.16 and 2.29±0.18 in group 2, 2.39±0.15 and 2.18±0.16 in group 3. Parathyroid hormone levels in the pre- and postoperative periods in 3 groups were (pmol/ml) 6.44±2.19 and 6.07±1.93, 6.13±1.49 and 5.6±1.62, 6.20±2.20 and 3.30±1.73 in groups 1, 2 and 3, respectively. The levels of hypocalcemia and parathormone reduction were: 1, 6.9% and 0%; 2, 13.56% and 5.08%; 3, 27.03% and 16.22%. There were no significant differences in parathormone and calcium levels in the group using ICG angiography (p>0.1). In the group using chromography, there were no significant differences in parathormone concentrations (p>0.05), but there were significant differences in total calcium concentrations (p≤0.01). In the control group, significant differences were found when both parameters were examined (p≤0.01). Calcium and parathormone concentrations in the postoperative period were also significantly lower in the control group (p≤0.01) than in the groups using specific methods of hypoparathyroidism prophylaxis. Thyroidectomy (p≤0.01) and Graves’ disease (p≤0.01) were the main predictors of hypoparathyroidism and/or hypocalcemia. Conclusion. The presented study demonstrates the inadequacy of using visual identification of parathyroid glands alone for the prevention of hypoparathyroidism. ICG angiography has demonstrated its efficacy and safety in our study. Chromography was slightly inferior to the first technique, but also reduced the incidence of postoperative hypoparathyroidism and hypocalcemia. The paper identifies the main risk factors: thyroidectomy and Graves’ disease. There was also an increased risk of hypoparathyroidism in patients with thyroid malignancy, a history of neck surgery, and a baseline decrease in ionized calcium.
Keywords: ICG-angiography, hypoparathyroidism, parathyroid hormone, hypocalcaemia, parathyroid glands, thyroid gland, thyroidectomy, hemithyroidectomy, indocyanine green, chromography
Conflicts of interest. The authors declare no conflicts of interest.
Financing. The paper was done without sponsorship.