Abstract 13491: Relative Associations of Exercise Capacity With Ankle-Brachial Index vs Left Ventricular Function in Patients at Risk of Heart Failure: Preliminary Findings From the NIL-CHF Study
Background: The ankle-brachial index (ABI) is associated with exercise capacity in pts with and without peripheral artery disease (PAD) but its significance relative to left ventricular (LV) function is unknown.
Hypothesis: ABI and LV function are jointly and independently associated with exercise capacity.
Methods: ABI, leg symptoms (Edinburgh Questionnaire), LV function (echo) and 6-min walk were assessed in 240 pts from the Nurse-led Intervention for Less Chronic Heart Failure (NIL-CHF) Study (≥45y and ≥1 of cardiovascular disease, type 2 diabetes, hypertension). PAD was defined by ABI ≤0.9. Pts with an ABI>1.4 or >0.9 despite known PAD/leg symptoms, were excluded (final n=191; 64±11y, 75% men). LV systolic and diastolic function were assessed by ejection fraction (≤45%=systolic dysfunction) and early diastolic tissue velocity (e’; ≤8cm/s=diastolic dysfunction), respectively. LV filling pressure was estimated by the ratio of early diastolic filling and tissue velocities (E/e’).
Results: Prevalent LV dysfunction was of mainly diastolic (73%) rather than systolic (8%) etiology. PAD was identified in 61 (32%) pts (10% symptomatic), but did not correlate with LV function. Sixteen pts (8%) could not complete the 6-min walk - an outcome predicted by ABI (OR 1.4 per 0.1 decrement; 95% CI 1.1 - 1.9), but not ejection fraction, e’ or E/e’ (adj. for age, sex, comorbidities and leg symptoms). In pts who completed the 6-min walk, total distance correlated with ABI (r=0.28, p<0.001), e’ (r=0.25, p<0.001) and E/e’ (r=-0.33, p<0.001), but not ejection fraction. When these variables were collectively analysed using multiple linear regression (Table; separate models for e’ and E/e’), ABI was the only determinant of 6-min walk distance independent of covariates. E/e’ showed a borderline significant inverse relation.
Conclusion: ABI was a more important determinant of exercise capacity than LV function, even in the setting of subclinical or clinical cardiac disease.
- © 2013 by American Heart Association, Inc.