Exercise training improved FMD and exercise capacity in stable CAD patients independent of the changes in inflammation, oxidative stress, or endothelial progenitor cells. The beneficial effects of exercise training on FMD and exercise capacity are inter-related, and more pronounced in those with baseline impaired exercise capacity.

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BackgroundWe sought to quantify plasma high sensitivity cardiac troponin (hs-cTnT) levels, their determinants, and their associations with left ventricular (LV) myocardial deformation in adult survivors of childhood acute leukaemias.Methods and ResultsOne hundred adult survivors (57 males) of childhood acute leukaemias, aged 24.1±4.2 years, and 42 age-matched controls (26 males) were studied. Plasma cTnT was determined using a highly sensitive assay. Genotyping of NAD(P)H oxidase and multidrug resistance protein polymorphisms was performed. Left ventricular function was assessed by conventional, three-dimensional, and speckle tracking echocardiography. The medians (interquartile range) of hs-cTnT in male and female survivors were 4.9 (4.2 to 7.2) ng/L and 1.0 (1.0 to 3.5) ng/L, respectively. Nineteen survivors (13 males, 6 females) (19%) had elevated hs-cTnT (>95th centile of controls). Compared to those without elevated hs-TnT levels, these subjects had received larger cumulative anthracycline dose and were more likely to have leukaemic relapse, stem cell transplant, and cardiac irradiation. Their LV systolic and early diastolic myocardial velocities, isovolumic acceleration, and systolic longitudinal strain rate were significantly lower. Survivors having CT/TT at CYBA rs4673 had higher hs-cTnT levels than those with CC genotype. Functionally, increased hs-cTnT levels were associated with worse LV longitudinal systolic strain and systolic and diastolic strain rates.ConclusionsIncreased hs-cTnT levels occur in a significant proportion of adult survivors of childhood acute leukaemias and are associated with larger cumulative anthracycline dose received, history of leukaemic relapse, stem cell transplant, and cardiac irradiation, genetic variants in free radical metabolism, and worse LV myocardial deformation.

Background:Exercise training improves endothelial function in patients with coronary artery disease (CAD) through unclear mechanisms. We hypothesized that mitochondrial dysfunction related to a lower habitual physical activity level (PAL) is associated with endothelial dysfunction. Methods and Results:We assessed habitual PAL by a validated International Physical Activity Questionnaire, brachial flow-mediated dilation (FMD) and serum lactate, pyruvate, fasting glucose and lipid profiles in 105 CAD patients (age 68±10; 87% men). As defined by the lactate/pyruvate ratio (LP ratio) ≥75 th percentile of the age-and sex-matched controls (ie, ≥18), mitochondrial dysfunction was observed in 33/105 (31%) patients. With decreasing PAL tertiles, there were significant linear trends of lower FMD (P=0.004) and higher LP ratio (P=0.009). Multivariate logistic regression found that the lowest compared with the highest PAL tertile (adjusted odds ratio=3.78, P=0.02) had more patients with high LP ratio. After adjustment for cardiovascular risk factors and medications, the lowest compared to the highest PAL tertile had significantly lower FMD (absolute decrease 1.25%, P=0.03); and high LP ratio was associated with impaired FMD (absolute reduction 1.09%, P=0.03). Conclusions:In CAD patients, a lower level of habitual PAL is associated with impaired FMD and increased prevalence of mitochondrial dysfunction as defined by high LP ratio. Moreover, high LP ratio predicts a lower FMD, suggesting that the occurrence of mitochondrial dysfunction with lower habitual PAL is associated with endothelial dysfunction in CAD patients. (Circ J 2012; 76: 2572 - 2578