The Impact of Additional Exercise Interventions on Physical Performance and Muscle Strength of Frail Patients After Open-Heart Surgery: A Randomized Trial

Background and Objectives: Frail patients after open-heart surgery often experience worse treatment outcomes in improving physical performance and muscle strength. As the functional recovery of frail patients after open-heart surgery is slower, conventional rehabilitation is frequently insufficient to achieve treatment goals. Therefore, the inclusion of additional exercise interventions in cardiac rehabilitation is becoming more relevant. The aim of this study was to assess and compare the effectiveness of additional exercise interventions—multicomponent and computer-based programs—applied along with conventional cardiac rehabilitation in improving the functional capacity and strength of frail patients after open-heart surgery. Materials and Methods: The population of this single-center, three-arm, parallel-group, randomized controlled trial comprised 153 frail patients aged more than 65 years who underwent open-heart surgery. All patients were randomized into three groups: control (CG, n = 51), intervention 1 (IG-1, n = 51), and intervention 2 (IG-2, n = 51). All groups received conventional rehabilitation program six times/week, while the IG-1 additionally received the multicomponent dynamic training program 3 times/week, and the IG-2, the combined computer-based program 3 times/week. The primary outcome measure was change in the Short Physical Performance Battery (SPPB) score. Secondary outcome measures included the 6 min walk distance (6MWD), peak workload, grip strength, and leg press. Primary and secondary outcome measures were assessed before and after cardiac rehabilitation. Results: A total of 138 patients completed rehabilitation (46 in each group), and their data were included in the main analysis that followed a per-protocol approach. Although significant differences in the primary outcome—the SPPB score—were found in each group while performing within-group comparisons (p < 0.001), no significant pre-to-post rehabilitation differences were observed compared to all three groups (p = 0.939), and the effect sizes were small. Regarding secondary outcome measures, within-group comparison revealed significant differences in all parameters of all groups (p < 0.05), except for the grip strength of both hands in the IG-1. Between-group comparisons showed that the pre-to-post 6MWD difference between the CG and the IG-1 was significant (p = 0.014), but the effect size was small (ES = 0.240). Moreover, significant pre-and-post leg press 1RM differences (p < 0.001) were found between the CG and the IG-1 as well as between the CG and the IG-2 with the effect sizes being moderate (ES = 0.480) and large (ES = 0.613), respectively. Conclusions: Within-group comparison showed that all three rehabilitation programs are effective in improving almost all parameters of physical performance and muscle strength in frail patients after open-heart surgery. However, between-group comparisons indicated that computer-based interventions were more effective in improving leg press 1RM with a large effect size, while multicomponent training resulted in more effective gains in the 6MWD, although with a small effect size. These findings suggest that in clinical practice, computer-based exercise programs may be more suitable for patients with muscle weakness, while multicomponent exercise programs may be for those with reduced endurance.