Cardiovascular Prehabilitation in Patients Awaiting Heart Transplantation- Addressing Clinical Needs (the PREHAB HTx Study)
Question
Does a 12-week multimodal PREHAB program including HIIT improve functional capacity, VO2peak, frailty, mental health, cognitive function, quality of life, and dietary habits compared with usual care in adults with advanced heart failure awaiting heart transplantation?
Summary
This multicentre randomized trial attempted to test a 12-week prehabilitation program for adults listed for heart transplantation. The program combined supervised cycle-ergometer HIIT, resistance training, stress management, and nutrition education. Recruitment and completion were very difficult: 84 patients were screened, 17 consented, only 4 were randomized, and 3 completed follow-up. The two PREHAB participants completed the nonexercise components, attended 67%-79% of exercise sessions, had 55%-56% compliance with target peak power output, and had no exercise-related adverse events. Because the trial was severely under-recruited, the authors could not test superiority versus usual care; results are best treated as feasibility and case-series evidence.
Methodology
- Adults with advanced heart failure listed for heart transplantation.
- 4 participants.
- Upright cycle ergometer HIIT plus resistance training.
- Work intervals: 30 seconds at 80%-100% peak power output after progression.
- Recovery: 30 seconds active recovery; 4 minutes recovery between two blocks.
- Intensity: Started at 50% PPO, progressed to 80%-100% PPO; possible increase to 150% PPO.
- 23 minutes HIIT plus 30 minutes resistance training.
- Twice weekly.
- 12 weeks.
- Multicentre, parallel-group randomized controlled trial that was under-recruited and reported remaining results as a case series.
- 6-minute walk test distance, VO2peak, Quality of life, and Exercise-related adverse events were tracked.
Outcomes
Recruitment and completion
Only 4 of 84 screened patients were randomized, far below the planned 60; 2/2 PREHAB and 1/2 usual-care participants completed follow-up.
6-minute walk test distance
Patient A in PREHAB improved from 427 to 465 m; Patient B follow-up was not reported. Patient C in usual care improved from 434 to 538 m; Patient D follow-up was not reported.
Descriptive case-series values only.
VO2peak
PREHAB Patient A improved from 14.9 to 15.5 mL/kg/min and Patient B improved from 15.0 to 16.0 mL/kg/min.
Descriptive case-series values only.
Exercise adherence and compliance
PREHAB patients attended 79% and 67% of sessions and complied with target peak power output 55% and 56% of the time.
Exercise-related adverse events
No exercise-related adverse events occurred in either PREHAB participant.
Insights
- For severe cardiovascular disease, HIIT evidence should be framed around medical screening, supervision, and conservative progression.
- A 30-second work/30-second active recovery structure can be clinically prescribed, but this study does not show it works better than usual care.
- Adherence barriers such as travel, scheduling, and medical instability may matter as much as workout design in advanced clinical populations.
Limitations
- Planned sample was 60, but only 4 patients were randomized.
- COVID-19 stopped recruitment and in-person research activities.
- Only one usual-care participant completed follow-up.
- Multimodal intervention bundled HIIT with resistance training, stress management, and nutrition.
- Exercise intensity compliance was only 55%-56%.
- Results were reported as a case series, limiting inference.
Safety
- No exercise-related adverse events occurred in the two PREHAB participants.
- Eligibility excluded several unstable or high-risk cardiovascular conditions.
- Medication and device contraindications were among reasons patients did not progress to randomization.