Effect of Preoperative Intranasal Dexmedetomidine on Postoperative Myocardial Injury in Patients Undergoing Coronary Artery Bypass Grafting

Purpose: To evaluate the effects of preoperative intranasal dexmedetomidine on postoperative myocardial injury biomarkers in patients undergoing on-pump coronary artery bypass grafting (CABG). Patients and Methods: In this randomized, double-blind, placebo-controlled trial, 70 patients undergoing on-pump CABG were assigned to receive intranasal dexmedetomidine (1 μg/kg) or saline 30 min before bedtime on the night before surgery and again 30 min before anesthesia induction. The primary outcome was serum high-sensitivity cardiac troponin T (hs-cTnT) at 24 h after surgery. Secondary outcomes included perioperative cardiac biomarkers, preoperative sleep quality, postoperative delirium, and adverse events. Results: For the prespecified primary outcome, hs-cTnT concentrations at 24 h after surgery were significantly lower in the dexmedetomidine group than in the control group (estimated marginal means, 170.29 vs 357.29 ng/L; P < 0.001). Postoperative creatine kinase-MB (CK-MB) concentrations were also lower in the dexmedetomidine group (all P < 0.05). N-terminal pro-B-type natriuretic peptide showed a significant group-by-time interaction (P = 0.030), although between-group differences at individual postoperative time points were not significant. The dexmedetomidine group had higher Leeds Sleep Evaluation Questionnaire scores (62 [60– 64] vs 44 [41– 50]; P < 0.001) and a lower incidence of postoperative delirium (14.3% vs 37.1%; P = 0.029). Adverse events, mechanical ventilation duration, and intensive care unit (ICU) length of stay did not differ significantly between groups. Conclusion: In this single-center trial, two-dose preoperative intranasal dexmedetomidine was associated with lower postoperative hs-cTnT and CK-MB concentrations, better subjective preoperative sleep quality, and a lower observed incidence of postoperative delirium. These findings are preliminary and require confirmation in larger, adequately powered multicenter randomized trials to determine whether the biomarker reductions translate into clinically meaningful cardiovascular benefits. Trial Registration: Chinese Clinical Trial Registry, ChiCTR2500111431.