Sex-based differences in serum cardiac troponin I, a specific marker for myocardial injury, after cardiac surgery

Background: Prevalence and causes of sex-based differences in morbidity and mortality secondary to cardiovascular disease remain controversial. Cardiac troponin I (cTnI) is a sensitive and specific marker for myocardial injury. Serial cTnI measurements have been used to identify perioperative myocardial cell injury. Objective: To determine whether sex influences the extent of myocardial injury during cardiac surgery, we measured perioperative cTnI in male and female patients. Design: A total of 17 male and 17 female patients were prospectively studied in an age- and case-matched manner. Arterial cTnI were obtained preinduction, 30 mins after the application of the aortic cross-clamp, at arrival to the intensive care unit, and on postoperative day 1. Setting: Tertiary cardiac surgery center at a major teaching hospital. Results: There was no difference between men and women in body mass index (kg/m²), duration of cardiopulmonary bypass, and aortic cross-clamp times. Preoperative cTnI measurements were similar in men (0.24 ± 0.15 ng/mL) and women (0.25 ± 0.13 ng/mL, mean ± SEM). The maximum serum cTnI occurred on postoperative day 1 in all patients, and it was 3-fold higher in men (18.5 ± 5.7 ng/mL) compared with women (6.4 ± 1.0 ng/mL). Conclusions: Men had markedly higher serum cTnI compared with women, although they were case matched with respect to age and cardiac risk factors. Our results may suggest there may be sex-related differences in the myocardial response to ischemia and reperfusion injury or intrinsic differences between the male and female myocardium.