Abstract 11387: Examining Mortality Based on Changes in Peak Oxygen Consumption After Cardiac Rehabilitation
Introduction: Cardiac rehabilitation (CR) in stable coronary heart disease (CHD) has been shown to improve mortality commensurate with levels of improvement in cardiorespiratory fitness (CRF). We examine here if relative improvement is as important as absolute improvement on mortality.
Hypothesis: We assessed the hypothesis that effects of absolute and relative changes in fitness, on mortality in a cardiac rehab population are different.
Methods: 890 subjects with stable CHD referred for CR were stratified according to baseline peak oxygen consumption (VO2) and post-CR improvement in VO2 (absolute group divided at 2.5 cc/kg/min, relative group divided at 20%) as measured during maximal cardiopulmonary exercise testing.
Results: After adjusting for age, gender, left ventricular ejection fraction, baseline VO2, and body mass index, participants with higher absolute improvement had a twofold lower mortality (HR 0.56, p<0.001), whereas high relative improvement had no significant mortality effect. When post-rehab VO2 was used as a covariate, VO2 improvement was no longer associated with changes in mortality (HR 0.82, p = 0.37). High relative improvement without high absolute improvement was independently associated with increased mortality (HR 2.63, p<0.001, Figure 1) and lower baseline fitness (p < 0.001) than groups with high absolute improvement.
Conclusions: In patients with CHD, absolute fitness after CR is the primary modulator of mortality, high absolute changes appear to be related to mortality benefits within the scope of increasing post-CR absolute CRF. This explains why high relative changes without associated absolute improvement reflects an especially low baseline CRF and high associated mortality. These results indicate that setting absolute targets for exercise capacity during CR can improve outcomes.
Author Disclosures: S. Kachur: None. A. De Schutter: None. C. Lavie: None. E. Jahangir: None. H. Dinshaw: None. R. Milani: None.
- © 2016 by American Heart Association, Inc.