Abstract 3190: Higher Habitual Physical Activity Improves Vascular Endothelial Function and Increases Endothelial Progenitor Cells in Patients with Stable Coronary Artery Disease
Purpose: Increased physical activity is associated with reduction in mortality from coronary artery disease (CAD) but mechanisms remain unclear. We hypothesized that higher physical activity may improve vascular function by increasing the number of circulating endothelial progenitor cells (EPCs) and altering the lipid profile.
Methods: We assessed habitual physical activity level (PAL) using a validated International Physical Activity Questionnaire in 116 patients (pts) (age 68±10; 81% men) with stable CAD. Number of circulating CD133/KDR+ EPCs was determined by flow cytometry. Brachial artery flow-mediated dilation (FMD) was measured by vascular ultrasound.
Results: 29/116 (25%) pts had high PAL (Physical activity >75th percentile of study population). There were no significant differences in age, sex, prevalence of smoking and statin use in pts with high or normal PAL (all P>0.05). Pts with high PAL had significantly higher FMD (4.7±2.5 vs 3.4±2.6%, P=0.02), % of EPCs (0.46±0.30 vs 0.30±0.15%, P<0.01) & lower LDL (2.1±0.5 vs 2.3±0.5 mmol/L, P=0.04) than pts with normal PAL. There were significant linear trends of increased FMD (P=0.02, Fig 1⇓) and EPCs (P=0.01, Fig 2⇓) with increasing PAL tertiles. Multivariate regression analysis showed that higher PAL tertiles (r=0.293, P=0.02) and lower LDL (r=−0.268, P=0.04), but not % EPCs were independent predictors for FMD.
Conclusion: Higher habitual PAL in pts with CAD was associated with higher FMD and EPC count. However, FMD only significantly correlated with increased PAL and lower LDL, but not EPC, suggesting that higher physical activity improves vascular function through mechanisms other than increasing EPC count.