ObjectiveTo investigate the perioperative change of parathyroid hormone (PTH) and its effect on cardiac function in patients with rheumatic heart disease.MethodsFrom January 2018 to June 2019, 76 patients were randomly divided into calcium supplement group (n=39) and control group (n=37). Mitral valve replacement was performed in both groups with cardiopulmonary bypass (CPB). Blood gas was measured immediately and every 6 h within 24 h after CPB. The patients in the calcium supplement group were given 1 g of calcium gluconate when hypocalcemia occurred, while the control group received no calcium supplementation. Values of radial arterial blood PTH and calcium ion (Ca2+) were measured in the two groups before operation (T1), at 30 min after starting CPB (T2), immediately after stopping CPB (T3), at 24 h after operation (T4), and at 48 h after operation (T5), respectively.ResultsThere were 71 patients enrolled in this study finally, including 38 in the calcium supplement group and 33 in the control group. The PTH values of patients in the two groups gradually increased, reached the peak at T3 time-point, then began to recover gradually. There was no significant difference between the two groups at T1, T2 or T3 time-point (P>0.05), while there were significant differences at T4 and T5 time-points (P<0.05). The Ca2+ values of the two groups gradually decreased after CPB, and gradually increased after blood ultrafiltration. There was no significant difference between the two groups at T1 or T3 time-point (P>0.05), while there were significant differences at T2, T4 and T5 time-points (P<0.05). The postoperative 24-hour values of ejection fraction (EF) and cardiac troponin T (cTnT) and the 72-hour total amount of epinephrine used in the calcium supplement group were (42.66±4.18)%, (1 881.17±745.71) ng/L, and (3.04±0.86) mg, respectively, and those in the control group were (40.76±3.39)%, (2 725.30±1 062.50) ng/L, and (4.69±1.37) mg, respectively. There were statistically significant differences in EF, cTnT and the 72-hour total amount of epinephrine used between the two groups (P<0.05). Values of PTH at T4 and T5 time-points were respectively negatively correlated with postoperative 24-hour value of EF (r=-0.324, P=0.006; r=-0.359, P=0.002), positively correlated with postoperative 24-hour value of cTnT (r=0.238, P=0.046; r=0.248, P=0.037) and the 72-hour total amount of epinephrine used (r=0.324, P=0.006; r=0.383, P=0.001).ConclusionsHyperparathyroidism occures after CPB, and calcium supplementation could relieve the hyperparathyroidism. Hyperparathyroidism may be related to postoperative cardiac insufficiency.