Physical Frailty is Modifiable in Young Cardiac Rehabilitation Patients.

Frailty is a standardized, quantitative metric used to assess multisystem physiologic reserve and vulnerability to poor health outcomes. Cardiac rehabilitation (CR) positively impacts patient outcomes, including frailty, in adult cardiovascular disease (CVD); however, both the frailty paradigm and CR are understudied in pediatric CVD. This retrospective, single-center cohort study aimed to determine baseline composite frailty for pediatric-onset CVD patients and examine its change throughout CR using a proposed frailty assessment tool. Youth with pediatric-onset CVD participating in CR were stratified into five CVD diagnostic groups: post-heart transplant (HTx) (n = 34), post-ventricular assist device (VAD) (n = 12), single ventricle (n = 20) and biventricular (n = 29) congenital heart disease, and cardiomyopathy (n = 25), and frailty was assessed at baseline and every 30 days during CR. Post-HTx and post-VAD groups had significantly higher median frailty scores at baseline (6/10 and 5.75/10, respectively) driven by reduced strength, gait speed, and functional status. All groups except post-VAD displayed a significant absolute reduction in frailty from baseline to 120 days (HTx: - 3.5; VAD: - 3; SV CHD: - 1; BV CHD: - 1; CM: - 1.5), with similar median post-CR scores (1-3/10 in all groups). These improvements did not significantly correlate with number of CR sessions attended. This study established that frailty exhibits discriminatory utility across pediatric-onset CVD groups at baseline and is significantly modifiable over time. Improvements in frailty and other fitness metrics are likely due to a combination of post-operative recovery, post-diagnosis pharmacological and lifestyle changes, and CR. Further study of this frailty tool is needed to explore its prognostic utility.