# Cardiovascular Prehabilitation in Patients Awaiting Heart Transplantation- Addressing Clinical Needs (the PREHAB HTx Study) PMID: 40894839 Journal: CJC open Published: 2025-05-22 Authors: Reed JL, Tulloch HE, Ross H, Terada T, Mistura M, Marçal IR, Oh P, Chih S ## 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. ## Population - Adults with advanced heart failure listed for heart transplantation. - Sample size: 4 - Age: Consented sample 44 +/- 9 years; randomized cases aged 33-58 years. - Sex: Randomized sample 3 men and 1 woman; consented sample 71% male. - Fitness level: Very low cardiorespiratory fitness in PREHAB cases, with VO2peak around 15 mL/kg/min. - Health status: Advanced heart failure awaiting heart transplantation. ## Methodology - Multicentre, parallel-group randomized controlled trial that was under-recruited and reported remaining results as a case series. - 12 weeks - University of Ottawa Heart Institute and University Health Network-Toronto General Hospital/Toronto Rehabilitation Institute prevention and rehabilitation centres in Canada. - Randomized and controlled study design. ## Protocol - PREHAB HIIT. - Modality: 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. - Sets or repetitions: Two 8-minute interval blocks; resistance training 6-10 exercises. - Intensity: Started at 50% PPO, progressed to 80%-100% PPO; possible increase to 150% PPO. - Session duration: 23 minutes HIIT plus 30 minutes resistance training. - Frequency: Twice weekly. - Program length: 12 weeks. - Progression: Workload increased by 10% after every other session until target PPO was reached; resistance load increased after 15 repetitions were achieved. - Usual care. - Modality: Medical management and activity advice. - Intensity: Regular activity according to symptoms, not structured. - Frequency: Clinic assessment every 1-3 months as needed. - Program length: 12 weeks follow-up. ## Outcomes ### Recruitment and completion Status: unclear 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 Status: mixed 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 Status: improved 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 Status: mixed 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 Status: no clear change No exercise-related adverse events occurred in either PREHAB participant. ## Practical 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 And Adherence - 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. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/40894839/) (pubmed) - [DOI](https://doi.org/10.1016/j.cjco.2025.05.009) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC12399121/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.