Giuliano, Catherine (2020) Optimising clinical and functional outcomes in older adults with chronic heart failure. PhD thesis, Victoria University.

Abstract

Globally, the age of patients with chronic heart failure (CHF) is increasing, which is presenting new challenges for providing exercise rehabilitation that is accessible, effective and well tolerated. This thesis explores factors affecting eligibility, referral and participation in exercise rehabilitation among older persons with CHF and investigates muscle-focused exercise modalities. This thesis consists of three exploratory studies, leading to a pilot randomised controlled trial. The exploration of factors affecting referral to, and participation in, exercise rehabilitation among older adults was achieved by two independent studies: first, a multiple regression analysis of factors associated with referral in patients discharged from Victorian public hospitals with acute heart failure; and second, an observation of recruitment data from the PRIME-HF1 randomised control trial, reporting eligibility, decline and recruitment rates. These two original studies found that while advancing age negatively influences participation, recruitment and engagement in exercise training among older adults is possible. Specifically, for every year of advancing age the likelihood of referral to outpatient exercise rehabilitation following an acute hospital admission with heart failure decreased by 2.5%. Furthermore, the presence of comorbidities—a common characteristics among older adults— was negatively associated with referral and participation. These studies are the first to describe factors that affect participation in outpatient exercise rehabilitation within the Australian context. In this way, they provide an understanding of current service utilisation, which will guide future service development. The aim to investigate muscle-focused exercise modalities was based on the muscle hypothesis of CHF which theorises that changes in skeletal muscle and peripheral tissues are primarily responsible for exercise intolerance in CHF. The meta-analysis investigating the effects of resistance training in patients with CHF showed that resistance training, as a standalone intervention, can increase muscle strength (one repetition maximum standardised change score = 0.60; 95% confidence interval [CI] 0.43, 0.77), aerobic capacity (change score mean difference [CSMD]: 2.71ml/kg/min; 1.96, 3.45) and quality of life (CSMD: - 5.71; - 9.85, -1.56). Furthermore, the PRIME-HF pilot randomised control trial showed that PRIME exercise training significantly increased VO2peak after eight weeks of training (2.4 mL/kg/min; 95% CI .7-4.1; p = .004), which was significantly greater in comparison to the usual care (combined aerobic and resistance training) exercise control group (ES 0.6), which showed minimal change in VO2peak after eight weeks of training (.2 mL/kg/min; 95% CI −1.5 to 1.8). Taken together, these findings support the hypothesis that PRIME may have potential advantages for older patients with HFrEF and could be a possible alternative exercise modality. In conclusion, as an investigation of a real-world clinical challenge, this research has shown that age should not be a barrier to exercise training in patients with CHF. The research showed that with appropriate and routine assessment, older adults with CHF can be safely enrolled into exercise training programs and achieve important improvements in clinical and functional outcomes. This research provides high-quality, preliminary evidence supporting PRIME and resistance training as alternative exercise modalities for patients with HFrEF.

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