Abstract 19319: Trends in Exercise Capacity at Baseline and Its Improvement After Cardiac Rehabilitation in Patients With Acute Myocardial Infarction Over 23 Years
Background: The influences of recent trends of aging of patients and shortening of the bedrest period on exercise capacity at the entry of cardiac rehabilitation (CR) and its improvement after CR in patients with acute myocardial infarction (AMI) are unknown.
Methods: We studied 1837 consecutive AMI patients who participated in our CR and underwent cardiopulmonary exercise testing at the beginning and the end of the 3-month program in 1992-2015. Clinical and exercise variables were compared between patients in 1992-1999 (Early cohort, n=590) and in 2007-2015 (Late cohort, n= 635).
Results: There were secular trends of decreasing peak oxygen uptake (PVO2 in ml/kg/min) at CR beginning (R= -0.07, P<0.01) and its improvement ( in %increase, R= -0.12, P<0.001). Compared with Early cohort, Late cohort was significantly older (59.7 to 64.5yrs, P<0.01) and had shorter hospital stay (35.7 to 20.7 days, P<0.01) and fewer CR session attendance (23.7 to 18.4 times, P<0.01). Although body weight-adjusted PVO2 (PVO2/BW) at the beginning of CR significantly decreased over time (21.4 to 20.5ml/kg/min, P<0.01), age-adjusted normalized PVO2 (PVO2 %predict) was unchanged (CR beginning 74.3 to 75.7%, P=0.10; CR end 82.7 to 82.7%, P=0.94). In contrast, the increase in PVO2 after CR showed a significant decline over time (12.8 to 8.9%, P<0.01). Multiple regression analysis indicated that age, PVO2/BW, number of sessions participated and sex were the independent predictors for rate of PVO2 change.
Conclusions: Combined effects of advanced aging, shortened bed rest period, and decreased CR attendance may have resulted in the trends of decreasing PVO2/BW with preserved normalized PVO2 at CR entry, and decreasing magnitude of PVO2 improvement after CR. This suggests that, to achieve a sufficient PVO2 improvement in CR in the current era, more frequent session attendance and more efficient training modes may be necessary.
Author Disclosures: K. Marume: None. M. Nakanishi: None. R. Kumasaka: None. S. Fukui: None. N. Kazuhiro: None. T. Arakawa: None. M. Yanase: None. T. Noguchi: None. S. Yasuda: None. Y. Goto: None.
- © 2016 by American Heart Association, Inc.