Abstract 2199: Left Ventricular Diastolic Function Impacts Age Based Differences in Exercise Capacity
Limited information exists regarding the echocardiographic and clinical predictors of exercise capacity and their effects on exercise with advancing age or by sex. We hypothesized that LV diastolic function (DF) impacts exercise capacity to a greater degree with advancing age. This was a prospective cohort study of consecutive patients undergoing routine exercise echocardiography with the Bruce protocol (n=2955). DF assessments at rest and exercise were performed. Those with echocardiographic exercise-induced ischemia and significant valvular disease were excluded. Univariate and multivariate analyses were conducted to determine the strongest echocardiographic and clinical predictors of exercise capacity (METs). Results were reported as unstandardized β coefficient (Standard Error) as outlined beside each variable. Age and sex interactions of these predictors with exercise capacity were determined. The strongest independent multivariate predictors of exercise capacity were female vs. male sex [−1.98 (0.07), p<0.0001], body mass index >30 kg/m2 [−1.24 (0.08), p<0.0001], age per 10 year increment [−0.85 (0.01), p<0.0001], mild resting diastolic dysfunction vs. normal [−0.70 (0.10), p<0.0001], and moderate/severe resting diastolic dysfunction vs. normal [−1.3 (0.13), p<0.0001]. LV filling pressures measured by a resting E/e’ ≥ 15 [−0.42 (0.14), p=0.004] or exercise E/e’≥ 15 [−0.31 (0.14), p<0.0001] similarly predicted a reduction in exercise capacity, each in separate multivariate analyses. The impact of impaired relaxation and left ventricular filling pressures on exercise capacity increased with advancing age (p<0.001 and p=0.02 respectively), and was most marked after age 50. These predictors had a similar negative effect on exercise capacity among men and women (p=NS). In conclusion, in this large population referred for exercise echocardiography and not limited by ischemia, resting DF and resting/exercise LV filling pressures independently predicted exercise capacity. The increasingly potent effect of impaired relaxation and exercise LV filling pressures with advancing age suggest that DF plays an important role in the development of exercise intolerance in the elderly.