Comparison of exercise treadmill test, flow mediated dilatation, and inflammation in individuals with low risk of adverse cardiovascular events

Background: The relationship between endothelial dysfunction, a risk factor for coronary artery disease, and the incidence of cardiovascular disease (CVD) in the general population is not well known. Objectives: To determine the utility of an exercise treadmill test (ETT) combined with inflammatory markers to show endothelial dysfunction for individuals with a low risk of adverse cardiovascular (CV) events. Methods: Biomarkers of inflammation (lipoprotein-related phospholipase A2 (Lp-PLA2) and high-sensitive C-reactive protein (hs-CRP)) and biomarkers of endothelial dysfunction (nitric oxide, oxidized low-density lipoprotein (Ox-LDL), and sialic acid) were assessed in 60 apparently healthy patients with a positive (+) or negative (-) ETT and across endothelial function assessed by flow mediated dilatation (FMD) and Lp-PLA2 tertiles. Results: Lp-PLA2 levels were increased in ETT (-) compared with ETT (+) patients. Half of ETT (-) patients were found to have levels of Lp-PLA2 in the highest tertile. There was a significant inverse relationship between ETT and inflammatory biomarkers when adjusted for age, Lp-PLA2 (r = -0.28, P = 0.04), or hs-CRP (r = -0.35, P = 0.01). No differences were found for biomarkers of endothelial dysfunction. All variables were reassessed across FMD tertiles. Total lipids, Ox-LDL, triglyceride, and Lp-PLA2 were higher for the lowest FMD tertile. Conclusion: The elevation of Lp-PLA2 in ETT (-) patients and the inverse relationship with inflammatory biomarkers, suggest that ETT cannot address endothelial dysfunction for individuals with apparently low risk of adverse CV events, and cannot be used for risk stratification of the general population. Keywords: Endothelial dysfunction, ETT, exercise treadmill testing, lipoprotein related phospholipase-2, LP-PLA2, vascular inflammation