Cardiac Rehabilitation
Expectations for Robotic Support in Acute Cardiac Rehabilitation of Older Patients ― Towards a New Era ―
2025 Volume 7 Issue 9 Pages 782-783
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2025 Volume 7 Issue 9 Pages 782-783
Multiple factors, such as malnutrition, sarcopenia, and frailty, significantly affect prognosis in older patients with heart failure (HF).1 Therefore, effective approaches to reducing sarcopenia and improving outcomes in patients with frailty participating in cardiac rehabilitation (CR) programs have great clinical importance. However, in real-world clinical settings for acute HF, CR has not yet been widely implemented, and intervention methods have not yet been established.
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In this issue of the Journal, Yamamoto et al. retrospectively analyzed the efficacy of a new acute-phase rehabilitation program using the lumbar-type hybrid assistive limb (HAL) in older patients with HF and frailty.2 Participants with improved symptoms of acute decompensated HF began a hospital-based CR program involving a HAL-assisted transition from sitting to standing and squatting exercises, starting an average of 5.5 days after hospitalization. Following a median of 5 CR sessions using HAL, the Short Physical Performance Battery (SPPB) score and quadriceps isometric strength (QIS) significantly improved. These improvements were significant in patients with higher CONUT scores at the start of CR, indicating poorer nutritional status (a population in which the effects of intensive rehabilitation are traditionally considered limited because of poor nutritional status).3
The study results suggested that HAL may be useful in acute CR for older patients, and that robot-assisted technology may serve as a complementary tool to promote recovery in patients who were previously believed to derive only marginal benefits from rehabilitation interventions owing to impaired nutritional reserves. This study’s results are consistent with those from previous reports supporting the usefulness of robotic technology in CR (Table). For instance, Kato et al. conducted a randomized trial of lumbar-type HAL training in patients with HF who had difficulty walking at the usual speed of healthy subjects, and they found significant gains in knee extensor strength, underscoring the potential for HAL to promote muscle engagement in patients with reduced volitional control.4 Hashimoto et al. demonstrated that balance exercise assisted robot (BEAR) training improved gait speed, SPPB scores, timed up-and-go test performance, and lower-limb strength in frail or prefrail older patients with cardiovascular disease.5 Emerging data support the safety and acceptability of wearable robotic support in more advanced cases. Just et al. showed that use of the Myosuit, an ultralight robotic exosuit, was safe, well-tolerated, and positively received among patients with NYHA class III HF, with 85% of participants indicating interest in continued use.6 In their postoperative population, Schoenrath et al. reported that patients undergoing early rehabilitation after open-heart surgery safely completed robot-assisted gait training with Lokomat®, achieving comparable gains in walking capacity and quadriceps strength as those undergoing traditional physiotherapy.7 Robot-assisted interventions consistently demonstrated safety, feasibility, and functional improvement across various disease severity and mobility limitations.
Summary of Key Studies on Robot-Assisted Cardiac Rehabilitation
| Reference | Population | Rehabilitation program | Effects |
|---|---|---|---|
| Kato et al. (2021)4 | 28 patients with HF who had difficulty walking at the usual speed of healthy subjects Randomized controlled trial |
“Chair-stand” training with the HAL system; 6–10 days period, 5–30 min/day |
↑ Walk distance ↑ Physical fitness ↑ Muscle strength of lower limbs |
| Hashimoto et al. (2022)5 | 52 older adults who had been hospitalized for worsening CVD Nonrandomized, single-arm prospective study |
4 months (1/week), for a total of 16 sessions as outpatients, balance exercises using the BEAR and aerobic exercises using an ergometer |
↑ Muscle strength of lower limbs ↓ Time of timed-up-and-go ↑ Gait speed ↑ Physical fitness |
| Just et al. (2022)6 | 20 patients in functional NYHA class III Prospective single-arm crossover pilot study |
Activities of daily life or participated in a single, standardized, 60-min rehabilitation exercise unit with and without the Myosuit |
↑ Chance to achieve CR goals |
| Schoenrath et al. (2015)7 | 10 patients after thoracotomy Prospective nonrandomized controlled pilot study |
10–30 min, 3/week gait therapy with the Lokomat® system on 11–12 on 20-point Borg scale and 2–3 sets of 6–10 quadriceps exercises using Lokomat® resistance |
↑ Muscle strength of lower limbs ↑ Walk distance |
This table summarizes representative clinical studies evaluating the effects of robot-assisted cardiac rehabilitation in older patients with cardiovascular disease. Various robotic systems,including HAL (Hybrid Assistive Limb), BEAR (Balance Exercise Assisted Robot), Myosuit, and Lokomat®, were used in different populations, settings, and study designs. Observed benefits include improvements in lower-limb muscle strength, physical performance, and mobility outcomes. BEAR, Balance Exercise Assisted Robot; CR, cardiac rehabilitation; CVD, cardiovascular disease; HAL, Hybrid Assistive Limb; HF, heart failure; NYHA, New York Heart Association.
In the present study, the patient population was notably older than that in previous reports, with a mean age in the mid-80s. Furthermore, all participants were certified under Japan’s long-term care insurance system as requiring support or care up to level 3, indicating a progressive state of frailty. Despite the limited duration of acute care hospitalization, CR combined with the HAL device use significantly improved SPPB scores. Older hospitalized individuals with suboptimal nutritional status have been considered less responsive to rehabilitation interventions owing to their limited physiological reserve.3 By demonstrating meaningful functional gains even in this fragile subgroup, the authors have expanded the conceptual and practical reach of early CR. Beyond functional metrics, the theoretical appeal of the HAL lies in its ability to reinforce intentional movement. If worn around the waist, the lumbar-type HAL improves the motor function of the trunk and lower limbs and promotes voluntary movements of the wearer by generating torque with power units based on the bioelectrical signals measured on the wearer’s skin. Electrodes attached to the skin covering the lumbar erector spinae muscles can detect the action potentials of nerves and muscles as bioelectrical signals, thereby sensing the wearer’s intention to perform the sit-to-stand movement. These mechanisms enable the HAL device to coordinate the level and timing of the torque to assist in the motion of the hip joint. This mechanism may facilitate neuromuscular re-education, promote neuroplasticity, and enhance the patient’s sense of agency.8,9 Such attributes are critical for short-term gains in strength or balance and fostering long-term self-efficacy and adherence to rehabilitation.
This study underscores the need to reimagine CR protocols for older patients during the inpatient phase of HF care. Randomized multicenter trials are needed to confirm the benefits of HAL-enhanced rehabilitation on long-term outcomes, such as quality of life, readmission rates, and cardiovascular events. Simultaneously, the exploration of patient-reported experiences and psychological engagement during HAL sessions can illuminate the broader rehabilitative value of such technologies. Additionally, economic analyses and implementation strategies are necessary to assess feasibility in resource-limited settings. Robot-assisted rehabilitation should be viewed as a evolving standard that complements and enhances conventional therapy, particularly for those at the margins of traditional care pathways. The HAL intervention represents a transformative shift in the approach to frailty and malnutrition during hospitalization for acute HF.
T.T. is a member of Circulation Reports’ Editorial Team.
