Cardiopulmonary exercise testing in patients with end-stage kidney disease: principles, methodology and clinical applications of the optimal tool for exercise tolerance evaluation

Abstract

Chronic kidney disease (CKD), especially end-stage kidney disease (ESKD), is associated with increased risk for cardiovascular events and all-cause mortality. Exercise intolerance as well as reduced cardiovascular reserve are extremely common in patients with CKD. Cardiopulmonary exercise testing (CPET) is a non-invasive, dynamic technique that provides an integrative evaluation of cardiovascular, pulmonary, neuropsychological and metabolic function during maximal or submaximal exercise, allowing the evaluation of functional reserves of these systems. This assessment is based on the principle that system failure typically occurs when the system is under stress and, thus, CPET is currently considered to be the gold-standard for identifying exercise limitation and differentiating its causes. It has been widely used in several medical fields for risk stratification, clinical evaluation and other applications but its use in everyday practice for CKD patients is scarce. This article describes the basic principles and methodology of CPET and provides an overview of important studies that utilized CPET in patients with ESKD, in an effort to increase awareness of CPET capabilities among practicing nephrologists.

The value of cardiopulmonary exercise testing and stress echocardiography in the prediction of all‐cause mortality in adults with end‐stage renal disease

“…While a degree of exercise limitation is highly prevalent and generally expected in renal populations (Pella et al, 2022), the pathophysiological mechanisms driving significant exercise intolerance in ESRD are not entirely understood. Inter‐participant variations in peak VO 2 are generally the result of complex changes in cardiovascular function, metabolism, anaemia, pulmonary health and neurocirculatory control, which are all influenced by comorbidities, general disease state and age; although it should be noted that the predictive capacity of peak VO 2 in the present study was independent of age (Lim et al, 2020; Pella et al, 2021; Pella et al, 2022) Many individuals with ESRD are also vulnerable to generalised skeletal muscle dysfunction/sarcopenia and cachexia, which carry implications for oxygen extraction via mitochondrial dysfunction and other skeletal muscle related metabolic processes (O'Driscoll et al, 2017; Pella et al, 2021). Ultimately, such systemic physiological decline inhibits oxygen transportation and/or utilisation, subsequently presenting as an impaired functional capacity (Lim et al, 2020).…”

“…Separately, this study demonstrated significantly greater anteroseptal wall thickness and borderline‐significant inferolateral wall thickness in those who died. The increase in LV wall thickness seen in ESRD is thought to not only parallel the high prevalence of hypertension, but also act as a compensatory adaptation to chronic pressure and volume overload (Pella et al, 2021; Ting et al, 2014), potentially via CKD‐specific risk factors that remain poorly categorised (Sárközy et al, 2019). Given that hypertension was not significantly different between groups in this cohort, this may have reduced the prevalence and thus the statistical power of inferolateral LV wall thickness as a marker of mortality.…”

Cardiorespiratory fitness and mortality risk in patients receiving hemodialysis: a prospective cohort

“…Our research group has been studying the effects of exercise on CRF and showed that combined exercise (i.e., aerobic and resistance) is beneficial in improving CRF in patients receiving HD 28 , 29 . In addition, as also recognized by Pella et al 30 , the importance of a periodic evaluation of the maximum physical effort in this population must be recognized as a wide spectrum of health, as it is already routinely performed in other clinical populations (e.g., cardiac and chronic pulmonary patients).…”

Effects of whole-body vibration exercise on physical function in patients with chronic kidney disease: a systematic review and meta-analysis

“…Cardiorespiratory fitness is a well-established indicator to assess cardiovascular health status and directly reflects the exercise capacity of an individual [ 42 ]. In patients with CKD, cardiorespiratory fitness decreases with worsening renal function [ 43 ] and is independently associated with higher mortality [ 44 ].…”