(P104) HIGH-INTENSITY INTERVAL TRAINING FOR HEART FAILURE AND POST-HEART TRANSPLANT: A SYSTEMATIC REVIEW AND META-ANALYSIS

Background: Heart failure (HF) continues to have a growing burden on health care systems with profound effects on patients’ health-related quality-of-life (HRQoL), exercise capacity, hospitalizations, and mortality. Heart transplant (HTx) is the gold standard treatment for medically refractory end-stage HF. However, HTx recipients continue to have reduced exercise capacity that in turn is linked with adverse long-term outcomes. High-intensity interval training (HIIT) has effectively improved fitness in numerous populations, including those with cardiovascular disease. We thus sought to evaluate the safety and impact of HIIT exercise interventions on exercise capacity, HRQoL, and vascular stiffness and function in patients with HF and post-HTx. We hypothesized that HIIT is a safe and effective strategy across the HF/HTx clinical continuum.

METHODS AND RESULTS: Embase, CINAHL, Cochrane, and MEDLINE databases were searched for randomized control trials using ‘cardiovascular disease’ and ‘HIIT’ search terms in May 2021 with an updated search performed in April 2022. We identified 1812 studies, of which 328 underwent full text review. Participants were HF patients or HTx recipients participating in ≥6-weeks of HIIT. Risk of bias was evaluated with Cochrane Collaboration’s Tool. Meta-analysis was done pooling outcomes using mean differences (MD, 95% confidence interval), and grouped by comparison group (HIIT vs. moderate-intensity continuous exercise (MICE) or control groups). A total of 1144 participants (185 HTx and 959 HF, 70% male, average 59.17 years of age) across 26 RCT (22 HF and 4 HTx) across 36 studies were included. HIIT improved exercise capacity (for peak oxygen consumption [VO2peak]) mean difference (MD) 2.17 (95% CI,1.17 to 4.75) ml/kg/min for HF, and 2.46 (95% CI, 1.64 to 3.29) for HTx participants), HRQoL (MD HF=0.53 [95%CI 0.09 to 0.97], MD HTx for mental=3.13 [95% CI -1.91 to 11.46]), and endothelial function (for FMD, MF HF=1.56 [95%CI, -1.69 to 4.81], MD HTx=3.40 [95% CI, 2.36 to 4.44]). Interventions were equally safe between HIIT and other interventions across HF and HTx groups with no differences (MD=0 across all) in adverse events directly related HIIT interventions vs other interventions or control arms.

Conclusion: HIIT is a promising, safe, and accessible tool with the potential to improve exercise capacity and long-term outcomes in HF and HTx populations. Key populations remain understudied, including women, children and adolescents, and those with congenital heart disease, highlighting key knowledge gaps for this potentially effective exercise strategy.