Perioperative myocardial cell injury: The relationship between troponin t and cortisol

Abstract

Study Objective: To investigate whether there is an association between Troponin T (TnT), reflecting myocardial cell injury, and cortisol, reflecting the degree of surgical trauma and associated stress, in light of our recent evaluation of TnT as a marker of perioperative myocardial cell injury. Design: Prospective, cohort study. Patients: 70 patients (67.4 ± 8.7 yrs) with definite or at-risk coronary artery disease (CAD) undergoing elective noncardiac surgery (vascular n = 38, abdominal n = 21, orthopedic n = 8) with general (n = 63) or regional (n = 4) anesthesia with postoperative on-demand analgesia. Measurements and Main Results: Morning blood samples for TnT (upper limit of normal: <0.2 ng/mL), CK-MB (reference range ≤12 U/L), and cortisol (normal morning range 7–25 μg/dL) were taken on the day before surgery, on the morning of surgery before induction of anesthesia, and on the first 5 postoperative days. Data were compared by analysis of variance. Three patients were excluded from the study because of incomplete blood samples of TnT or cortisol. Preoperative mean cortisol levels (μg/dL ± SD) were within the normal range and equal in TnT positive (n = 13) and negative (n = 54) patients (16.1 ± 4.5 vs. 15.6 ± 5.8). On the 1st postoperative day, there was a substantial increase of cortisol in the TnT positive group (35.7 ± 26.9). Cortisol remained high until the 5th postoperative day (24.7 ± 9.4). There was a significant difference in the cortisol concentration in TnT-positive compared to TnT-negative patients (p < 0.001), a significant difference in the perioperative cortisol concentration over time (p < 0.05), and a significant interaction (p < 0.001). But there was no consistent temporal relationship between the increase of TnT and the increase of cortisol. Conclusions: The significant relationship between a highly sensitive and specific marker of myocardial cell injury and a marker of stress suggests that cardiac-risk patients undergoing stressful surgical procedures might benefit from close perioperative TnT monitoring with early recognition of myocardial cell injury.