Variation of Procalcitonin Level in Elective Cardiac Surgery at a Tertiary Cardiac Centre: A Prospective Longitudinal Study

ABSTRACT Background Procalcitonin (PCT) levels often rise after cardiac surgery due to an ongoing postoperative inflammatory response. The changes in PCT levels are useful for the early detection of postoperative infections. We assessed the variation of procalcitonin levels in patients undergoing elective cardiac surgery at the leading tertiary cardiac centre to support clinical decision‐making and future studies in our setting. Methods An observational longitudinal study was conducted among 273 adults who underwent elective cardiac surgery. Patients with perioperative signs of infections, systemic infections, and use of corticosteroids within the last 7 days were excluded. SPSS version 26 was used for data analysis. We measured baseline serum PCT levels before surgery, and on days 1, 3, and 5 after surgery. A p ‐value < 0.05 was considered statistically significant. Results Our study showed a characteristic double peak in procalcitonin levels. The baseline PCT level was 0.10 ng/mL. Postoperatively, the median PCT values were 11.9 ng/mL on day 1, 6.8 ng/mL on day 3, and 15.9 ng/mL on day 5. The Friedman test showed a statistically significant difference in the levels of PCT at the four time points ( χ 2 (3) = 417.721, p < 0.001). Kendall's coefficient of concordance (W = 0.529) indicated moderate to strong agreement in this trend. Post hoc Wilcoxon Signed‐Rank test with Bonferroni correction confirmed a significant rise on day 1, a decline by day 3, and a subsequent increase on day 5. Conclusion There was a dynamic postoperative variation in levels of PCT. A secondary rise in PCT levels may indicate the development of delayed complications like Surgical Site Infections and Sepsis requiring clinical attention. Therefore, monitoring serial PCT trends over time is more important than reliance on isolated values.