Individual Differences in Response to Supervised Exercise Therapy for Peripheral Artery Disease

Trainability for cardiopulmonary fitness is low in patients with peripheral artery disease

AIMS

In patients with peripheral arterial disease (PAD), exercise therapy is recommended to relieve leg symptoms, as noted in the 2016 AHA/ACC and 2017 ESC/ESVS guidelines. We assessed the trainability for cardiopulmonary fitness (CPF) and quality of life (QOL); three distinct patient types, namely, PAD, heart failure (HF), and stroke, were compared.

METHODS AND RESULTS

This is a multicentre, retrospective analysis of prospectively collected data from three clinical studies. Data collected from 123 patients who completed 36 sessions of supervised aerobic training of moderate intensity were analysed, with 28 PAD, 55 HF, and 40 stroke patients totalling 123. Before and after training, cardiopulmonary exercise testing with non-invasive cardiac output monitoring and QOL evaluation using a 36-Item Short Form Survey (SF-36) were performed. Non-response was defined as a negative change in the post-training value compared with that in the pre-training value. The result showed an improvement in CPF in all three groups. However, cardiorespiratory fitness (CRF) increased by a lesser extent in the PAD group than in the HF and stroke groups; the physical and mental component scores (MCS) of SF-36 exhibited a similar pattern. Non-response rates of peak V˙O2, oxygen uptake efficiency slope, and MCS were higher in the PAD group. In the PAD group, non-responders regarding peak V˙O2 had a higher pulse wave velocity than responders.

CONCLUSION

In patients with PAD following exercise therapy, CRF and QOL improved to a lesser extent on average; their non-response rate was also higher compared with that of HF or stroke patients. Therefore, a higher dose of exercise might be needed to elicit adaptation in PAD patients, especially those with high pulse wave velocity.

Anatomic patterns in claudicants who fail supervised exercise therapy

OBJECTIVE

Patients with intermittent claudication (IC) from peripheral arterial disease (PAD) have significant improvement with supervised exercise therapy (SET). However, many patients have progressive disease that will ultimately require revascularization. We sought to determine whether the anatomic patterns of PAD were associated with response to SET.

METHODS

We prospectively enrolled patients with IC at the West Haven, Connecticut Veterans Health Administration between June 2019 and June 2022. Patients were classified based on the level of their arterial disease with >50% obstruction. SET failure was defined as progressive symptoms or development of critical limb-threatening ischemia (CLTI) requiring revascularization.

RESULTS

Thirty-eight patients with PAD were included. Thirteen patients (34.2%) had significant common femoral artery (CFA) disease, and 25 (65.8%) had non-CFA disease. Over a median follow-up of 1407 days, 11 patients (84.6%) with CFA disease failed SET as compared with three patients (12.0%) with non-CFA disease (P < .001). Patients with CFA disease were more likely to develop CLTI (46.2% vs 4.0%; P = .001) and have persistent symptoms (38.5% vs 8.0%; P = .02). Patients with CFA disease had significantly lower post-SET ankle-brachial index (0.58 ± 0.14 vs 0.77 ± 0.19; P = .03). In multivariate analysis, the only variable associated with SET failure was CFA disease location (odds ratio, 68.75; 95% confidence interval, 5.05-936.44; P = .001).

CONCLUSIONS

Patients with IC from high-grade CFA atherosclerosis are overwhelmingly likely to fail SET, potentially identifying a subset of patients who benefit from upfront revascularization.

Lower limb revascularization leads to faster walking but with less efficient mechanics in claudicating patients

Peripheral artery disease (PAD) is characterized by reduced blood flow to the extremities due to atherosclerosis. Studies report impaired gait mechanics in patients with lower extremity PAD. We hypothesized that revascularization surgery would improve gait mechanics when quantified by net lower limb joint work across the stance phase of walking. We performed gait analyses in 35 patients with PAD and 35 healthy, older adults. Patients with PAD performed a walking protocol prior to and six months following revascularization surgery. Healthy adults only took part in a single walking session. Lower limb joint powers were calculated using inverse dynamics and were integrated across early, middle, and late stance phases to determine the work performed during each phase (J kg-1). The work mechanical ratio between positive-producing and negative-producing phases of stance was calculated for each lower-limb joint. Self-selected walking speed significantly increased from 1.13 ± 0.2 ms-1 to 1.26 ± 0.18 ms-1 in patients following revascularization (p < 0.001). We observed a significant decrease in positive late stance work (p < 0.001) in conjunction with more negative work during early stance (p < 0.001) in patients following revascularization. Revascularization surgery led to faster walking without an increase in the ankle joint's mechanical ratio. Our results suggest faster walking was achieved via work done at the hip rather than the ankle. These findings suggest that additional therapies that facilitate the restoration of muscle, tissue, and nervous system damage caused by years of having reduced blood flow to the limbs might still be beneficial following revascularization.

Supervised exercise therapy for patients with peripheral artery disease: Clinical update and pathways forward

Peripheral artery disease (PAD) is an atherosclerotic vascular disease resulting in widespread morbidity and mortality, particularly among older adults. One first-line therapy to improve symptoms, function, and clinical outcomes in PAD is supervised exercise therapy (SET), which is based primarily on a structured, start-and-stop walking protocol and is implemented in cardiac rehabilitation programs. SET is supported by a Class IA guideline for patients with symptomatic PAD; however, despite the effectiveness of SET and the 2017 CMS decision to cover SET for PAD, challenges of awareness, access, and implementation of SET persist. Recent efforts to address these challenges include digital health and hybrid approaches to SET that may minimize barriers to care by delivering SET in more innovative, flexible formats. Further study is needed to understand barriers, improve awareness, and implement SET in more equitable and accessible ways.

International Exercise Recommendations in Older Adults (ICFSR): Expert Consensus Guidelines

The human ageing process is universal, ubiquitous and inevitable. Every physiological function is being continuously diminished. There is a range between two distinct phenotypes of ageing, shaped by patterns of living - experiences and behaviours, and in particular by the presence or absence of physical activity (PA) and structured exercise (i.e., a sedentary lifestyle). Ageing and a sedentary lifestyle are associated with declines in muscle function and cardiorespiratory fitness, resulting in an impaired capacity to perform daily activities and maintain independent functioning. However, in the presence of adequate exercise/PA these changes in muscular and aerobic capacity with age are substantially attenuated. Additionally, both structured exercise and overall PA play important roles as preventive strategies for many chronic diseases, including cardiovascular disease, stroke, diabetes, osteoporosis, and obesity; improvement of mobility, mental health, and quality of life; and reduction in mortality, among other benefits. Notably, exercise intervention programmes improve the hallmarks of frailty (low body mass, strength, mobility, PA level, energy) and cognition, thus optimising functional capacity during ageing. In these pathological conditions exercise is used as a therapeutic agent and follows the precepts of identifying the cause of a disease and then using an agent in an evidence-based dose to eliminate or moderate the disease. Prescription of PA/structured exercise should therefore be based on the intended outcome (e.g., primary prevention, improvement in fitness or functional status or disease treatment), and individualised, adjusted and controlled like any other medical treatment. In addition, in line with other therapeutic agents, exercise shows a dose-response effect and can be individualised using different modalities, volumes and/or intensities as appropriate to the health state or medical condition. Importantly, exercise therapy is often directed at several physiological systems simultaneously, rather than targeted to a single outcome as is generally the case with pharmacological approaches to disease management. There are diseases for which exercise is an alternative to pharmacological treatment (such as depression), thus contributing to the goal of deprescribing of potentially inappropriate medications (PIMS). There are other conditions where no effective drug therapy is currently available (such as sarcopenia or dementia), where it may serve a primary role in prevention and treatment. Therefore, this consensus statement provides an evidence-based rationale for using exercise and PA for health promotion and disease prevention and treatment in older adults. Exercise prescription is discussed in terms of the specific modalities and doses that have been studied in randomised controlled trials for their effectiveness in attenuating physiological changes of ageing, disease prevention, and/or improvement of older adults with chronic disease and disability. Recommendations are proposed to bridge gaps in the current literature and to optimise the use of exercise/PA both as a preventative medicine and as a therapeutic agent.