Biphasic elevation of bilirubin oxidation during myocardial ischemia reperfusion

Bilirubin is negatively associated with hemoglobin a(1c) independently of other cardiovascular risk factors in apparently healthy Japanese men and women

BACKGROUND

Serum total bilirubin (TB) is a potent antioxidant and may be a negative risk factor of cardiovascular disease. In non-diabetic adults, hemoglobin A(1c) (HbA(1c)), but not fasting plasma glucose, is an independent risk factor of cardiovascular disease.

METHODS AND RESULTS

Linear regression using TB as a dependent variable and cardiovascular risk factors, including HbA(1c), as independent variables, linear regression using HbA(1c) as a dependent variable and other cardiovascular risk factors, including TB, as independent variables, and logistic regression using the highest decile (≥ 5.4%) of HbA(1c) as a dependent variable and TB and other cardiovascular risk factors as independent variables were performed for 893 apparently healthy male smokers, 1,607 male nonsmokers, and 1,680 women. The standardized regression coefficient of HbA(1c) for TB and that of TB for HbA(1c) was -0.12 (P = 0.007) and -0.06 (P = 0.02), respectively, in the smokers, -0.20 (P < 0.0001) and -0.07 (P < 0.0001), respectively, in the nonsmokers, and -0.21 (P < 0.0001) and -0.14 (P < 0.0001), respectively, in the women. The odds ratio of 1 SD increment in TB for HbA(1c) ≥ 5.4% was not significant in the smokers, 0.67 (P = 0.002) in the nonsmokers, and 0.55 (P<0.0001) in the women.

CONCLUSIONS

Bilirubin was negatively associated with HbA(1c) independently of other cardiovascular risk factors in apparently healthy Japanese men and women. The association was weak in male smokers.

Change in ischemia-modified albumin and its clinical significance during exercise stress testing

BACKGROUND

There is little data about the additive effects of ischemia-modified albumin (IMA) on the exercise stress test (EST) used for the screening of ischemic heart disease. The relationship between myocardial ischemic burden and the change in IMA (DeltaIMA) during EST was investigated.

METHODS AND RESULTS

EST was performed using the Bruce protocol to evaluate chest pain or exertional dyspnea in 155 patients (men 89, 53+/-13 years). Blood samples for IMA were obtained before and immediately after EST. According to the EST results and the pattern of DeltaIMA, patients were categorized into 3 groups (none was classified as EST(-)/DeltaIMA(+)): (1) (EST(-); (2) EST(+)/DeltaIMA(-); and (3) EST(+)/DeltaIMA(+). After EST, 60 of 155 (38.7%) patients were EST(+) and 14/60 (23.3%) were EST(+)/DeltaIMA(+). Duke treadmill score was significantly lower in the EST(+)/DeltaIMA(+) group compared with the other groups (-9.0+/-7.9, -1.7+/-4.2, 6.7+/-4.4, respectively, P<0.001); 43/60 (72%) patients with EST(+) underwent coronary angiography and the proportion of patients with a large ischemic burden was higher in the EST(+)/DeltaIMA(+)group compared with the EST(+)/DeltaIMA(-) group (72.7% vs 15.6%, P=0.001).

CONCLUSIONS

Increased IMA after EST suggests a large ischemic burden in coronary artery disease, so the DeltaIMA during EST may be useful for predicting the severity of myocardial ischemia.