Exercise aortic stiffness: reproducibility and relation to end-organ damage in men

Resting aortic stiffness (pulse wave velocity; aortic PWV (aPWV)) independently predicts end-organ damage and mortality. Exercise haemodynamics have been shown to unmask cardiovascular abnormalities, otherwise undetectable at rest, but the response of aPWV to exercise has never been examined. This study aimed to develop a technique to measure exercise aPWV, determine reproducibility and relation to subclinical end-organ damage with aging. Healthy younger (n=17, 30±8 years) and older (n=18, 54±8 years) untreated men underwent cardiovascular assessment at rest and during low intensity semirecumbent cycling. Tonometry was used to assess aPWV and central blood pressure (BP). All participants underwent 24 h ambulatory BP (ABP) monitoring. Kidney function was assessed by estimated glomerular filtration rate (eGFR). Fifteen participants had testing repeated within 28±18 days. Exercise aPWV had good reproducibility (mean difference=-0.35±0.61 m s(-1), intraclass correlations=0.874, P<0.001) and was increased 26% above resting values in younger men (5.8±0.9 vs 7.3±1.6 m s(-1), P<0.001) and 19% above resting values in older men (6.3±1.0 vs 7.4±0.9 m s(-1), P<0.001). Exercise, but not resting, aPWV was significantly correlated with eGFR in older men (r=-0.633, P=0.005), and this was maintained after correction for age, body mass index and daytime systolic ABP (r=-0.656, P=0.008). Conversely, in younger men there was no significant association between eGFR and aPWV either at rest (r=-0.031, P=0.906) or during exercise (r=-0.117, P=0.655). Exercise aPWV is reproducible and significantly associated with kidney function in healthy older men. Further studies to determine the physiology and clinical relevance of raised exercise aPWV are warranted.