Perioperative Dexmedetomidine Exposure and Postoperative Cardiac Biomarkers after Cardiopulmonary Bypass: A Retrospective Cohort Study

Abstract

Objectives: To evaluate the association between perioperative dexmedetomidine exposure and postoperative myocardial injury biomarkers in adults undergoing cardiopulmonary bypass (CPB)–assisted cardiac surgery. Methodology: This retrospective cohort study was conducted at Lady Reading Hospital, Peshawar, Pakistan, from 1 January 2023 to 31 December 2024. Adult patients undergoing CPB-assisted cardiac surgery with at least one postoperative high-sensitivity cardiac troponin T (hs-cTnT) measurement within 72 hours were included. Dexmedetomidine exposure was categorized by initiation timing. The primary outcome was peak hs-cTnT within 72 hours. Secondary outcomes included hs-cTnT at ICU admission, peak creatine kinase–MB (CK-MB), ventilation duration, ICU length of stay, documented delirium, bradycardia requiring intervention, and in-hospital mortality. Log-linear regression models were used, adjusting for CPB time and aortic cross-clamp time. Timing-restricted sensitivity analyses excluded ICU-only initiation for time-dependent outcomes. Results: Of 261 screened patients, 232 were included (dexmedetomidine n=122; control n=110). Peak hs-cTnT was lower in dexmedetomidine-exposed patients (median 1120 vs 1360 ng/L; p=0.004), with an adjusted geometric mean ratio of 0.84 (95% CI 0.73–0.96; p=0.012). Peak CK-MB was also lower (p=0.03). Dexmedetomidine exposure was associated with shorter ventilation duration, shorter ICU stay, lower documented delirium, and higher bradycardia requiring intervention. In timing-restricted analyses, the ventilation-duration association persisted, while ICU length of stay attenuated. In-hospital mortality did not differ. Conclusion: Perioperative dexmedetomidine exposure was associated with lower postoperative cardiac biomarker release, with cautious interpretation warranted for time-dependent outcomes.