Predictors of Improvement in Exercise Capacity After Cardiac Rehabilitation Differ Between Octogenarian and Young-Old Patients With Acute Myocardial Infarction

Background: Whether the magnitude and predictors of improvement in exercise capacity after cardiac rehabilitation (CR) are the same between young-old (YO) and octogenarian (OCT) patients with acute myocardial infarction (AMI) is unknown. Methods and Results: We studied 284 YO (age range 65–69 years; mean [±SD] 67±1 years) and 65 OCT (age range ≥80 years; mean [±SD] 83±2 years) patients who participated in a post-AMI CR program. After 3 months of CR, peak oxygen uptake (PV^· O2) measured during cardiopulmonary exercise testing improved significantly in both age groups (P<0.01), although the percentage increase in PV^· O2 (%∆PV^· O2) was significantly smaller in the OCT than YO group (5.4±13.7% vs. 10.0±12.8%; P<0.01). Multiple regression analysis demonstrated that independent predictors of %∆PV^· O2 were the number of outpatient CR (OPCR) sessions attended (P=0.015), left ventricular ejection fraction (P=0.028), and baseline PV^· O2 (P=0.0007) in the YO group; and the number of sessions attended (P=0.018), atrial fibrillation (P=0.042), and the presence of nutritional risk (Geriatric Nutritional Risk Index ≤98; P=0.036) in the OCT group. Conclusions: The predictors of improvement in exercise capacity after CR differed between the YO and OCT patients with AMI. To obtain a greater improvement in PV^· O2 in CR, frequent OPCR session attendance may be necessary in both groups; in addition, particularly in OCT patients, better nutritional status may be important.