Elevated baseline hs-cTnT levels predict exercise-induced myocardial ischemia in patients with peripheral arterial disease

Abstract

IntroductionDue to the systemic nature of atherosclerosis, the prevalence of coronary artery disease (CAD) is high in patients with peripheral arterial disease (PAD). A biochemical assay for assessing cardiac risk might improve clinical evaluation of PAD patients. The aim of this study was to investigate whether a new high-sensitivity cardiac Troponin T (hs-cTnT) assay can predict exercise-induced myocardial ischemia in PAD patients without clinical signs of CAD. MethodsSixty-eight ambulatory patients with Fontaine stage II PAD underwent treadmill stress testing to maximum walking distance. Myocardial ischemia was assessed using a 2-lead Holter ECG and ST-segment depression of ≥0.2mV was considered significant. Hs-cTnT was measured from serum samples taken at baseline as well as 5, 10 and 30min after exercise. ResultsHs-cTnT baseline levels were significantly higher (19.3ng/L (5.0; 20.2ng/L) vs. 6.6ng/L (4.4; 9.4ng/L); p=0.037) and increase of serum levels 5min after cessation of exercise was more pronounced (1.09ng/L (0.23; 1.80ng/L) vs. 0.22ng/L (−0.1; 0.65ng/L), p=0.032) in ECG positive patients compared to individuals with normal ECG. Logistic regression analysis identified the baseline hs-cTnT serum level as an independent risk factor for developing significant exercise-induced ST-segment depression (odds ratio 1.2 per 1-unit increase, p=0.015). ConclusionsIn patients with PAD, exercise-induced myocardial ischemia is associated with elevated baseline levels and a significant early increase of hs-cTnT serum levels.