Central Arterial Stiffness is Not Responsible for Systolic Hypertension in the Highly Trained Elderly

Recent studies have shown that systolic hypertension in the elderly is associated with increased aortic stiffness. In contrast, our laboratory and others have shown that Masters athletes (MA) have more compliant aortas than age-matched controls. However, we also found a high incidence (19 of 43, 44%) of diagnosed systolic hypertension in MA. PURPOSES: Therefore, the purpose of this study was to examine whether hypertension in MA is associated with increased aortic stiffness. METHODS: Arterial compliance was evaluated in 4 MA > age 65 with systolic hypertension (MA-HTN) by three indices; 1) central arterial pulse wave velocity (cPWV), 2) systemic arterial compliance index (SACi=stroke volume index/pulse pressure), and 3) Modelflow "aortic age", which we developed to quantify the structural component of aortic aging independent of ambient blood pressure. These results were compared to both age-matched healthy sedentary individuals (Sed-Norm, N=10) and MA without hypertension (MA-Norm, N=13). RESULTS: cPWV was slower in MA-HTN (982±372 cm/sec) compared to Sed-Norm (1294±440 cm/sec), but faster than MA-Norm (794±120 cm/sec) (P=0.003, ANOVA). Similarly, SACi was higher in MA-HTN (0.95±0.34 ml/mmHg/m∧2) compared to Sed-Norm 0.70±0.22 ml/mmHg/m∧2), but lower than MA-Norm (1.01±0.20 ml/mmHg/m∧2) (P=0.011). Modelflow aortic age was comparable between MA-HTN (73±21 yrs) and Sed-Norm (73±14 yrs), both of which were age-appropriate while the aortic age of MA-Norm was younger than their chronological age (41±13 yrs) (P<0.001). Stroke volume index was larger in MA-HTN (46±6 ml/m∧2) compared to Sed-Norm (39±9 ml/m∧2), but lower than MA-Norm (51±9 ml/m∧2) (P=0.014). CONCLUSIONS: MA-HTN have aortic compliance which is at least equivalent to and likely greater than age-matched "normotensive" controls, though stiffer than MA without HTN. Therefore, the presence of systolic hypertension in MA-HTN does not seem to be explained by increased aortic stiffness, at least compared to sedentary seniors without HTN. We speculate that an age-appropriate (though relatively stiff compared to MA-Norm, or young individuals) aorta coupled with a larger stroke volume from an athlete's heart could contribute to systolic hypertension in MA-HTN. Supported by the NIH grant AG17479-05 and the NSBRI Career Development Award EO00007