BackgroundPrevalence 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.ObjectiveTo determine whether sex influences the extent of myocardial injury during cardiac surgery, we measured perioperative cTnI in male and female patients.DesignA 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.SettingTertiary cardiac surgery center at a major teaching hospital.ResultsThere 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).ConclusionsMen 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.