Assessment of Exercise Intolerance in Patients with Pre-Dialysis CKD with Cardiopulmonary Function Testing: Translation to Everyday Practice

CA125 outperforms NT-proBNP in the prediction of maximum aerobic capacity in heart failure with preserved ejection fraction and kidney dysfunction

Background

Heart failure with preserved ejection fraction (HFpEF) often coexists with chronic kidney disease (CKD). Exercise intolerance is a major determinant of quality of life and morbidity in both scenarios. We aimed to evaluate the associations between N-terminal pro-B-type natriuretic peptide (NT-proBNP) and carbohydrate antigen 125 (CA125) with maximal aerobic capacity (peak VO2) in ambulatory HFpEF and whether these associations were influenced by kidney function.

Methods

This single-centre study prospectively enrolled 133 patients with HFpEF who performed maximal cardiopulmonary exercise testing. Patients were stratified across estimated glomerular filtration rate (eGFR) categories (<60 ml/min/1.73 m2 versus ≥60 ml/min/1.73 m2).

Results

The mean age of the sample was 73.2 ± 10.5 years and 56.4% were female. The median of peak VO2 was 11.0 ml/kg/min (interquartile range 9.0-13.0). A total of 67 (50.4%) patients had an eGFR <60 ml/min/1.73 m2. Those patients had higher levels of NT-proBNP and lower peak VO2, without differences in CA125. In the whole sample, NT-proBNP and CA125 were inversely correlated with peak VO2 (r = -0.43, P < .001 and r = -0.22, P = .010, respectively). After multivariate analysis, we found a differential association between NT-proBNP and peak VO2 across eGFR strata (P for interaction = .045). In patients with an eGFR ≥60 ml/min/1.73 m2, higher NT-proBNP identified patients with poorer maximal functional capacity. In individuals with eGFR <60 ml/min/1.73 m2, NT-proBNP was not significantly associated with peak VO2 [β = 0.02 (95% confidence interval -0.19-0.23), P = .834]. Higher CA125 was linear and significantly associated with worse functional capacity without evidence of heterogeneity across eGFR strata (P for interaction = .620).

Conclusions

In patients with stable HFpEF, NT-proBNP was not associated with maximal functional capacity when CKD was present. CA125 emerged as a useful biomarker for estimating effort intolerance in HFpEF irrespective of the presence of CKD.

Efficacy and safety of ultrafiltration combined with haemodialysis in patients with uraemia who cannot tolerate dialysis because of hypotension

OBJECTIVE

To evaluate the efficacy and safety of ultrafiltration (UF) combined with haemodialysis (HD) sequential therapy in patients with intradialytic hypotension (IDH) and water retention.

METHODS

A total of 53 uraemia patients with IDH who could not tolerate dehydration and significant water and sodium retention (net weight gain of more than 4 kg) were randomly divided into control group (28 cases) and treatment group (25 cases). After adjusting dialysis parameters (blood pump speed and excessive filtration), HD was tried again in the control group, and UF combined with HD was given sequential treatment in the treatment group. Outcome measures included efficacy measures (duration of treatment, total water removal, weight loss, dyspnoea score and left ventricular ejection fraction) and safety measures (heart rate, blood pressure, IDH incidence, bleeding and thromboembolic events).

RESULTS

In terms of efficacy indicators, In the sequential treatment group, the duration of treatment (740 ± 168 min vs. 380 ± 94 min, p < 0.05), total water removal (5280 ± 968 mL vs. 2980 ± 765 mL, p < 0.05) and the weight loss (2756 ± 537 g vs. 1421 ± 362 g, p < 0.05) was significantly higher than that of control group. Postoperative dyspnoea score (1.92 ± 0.400 vs. 3.32 ± 0.476, p < 0.05), left ventricular ejection fraction (LVEF; 49.25 ± 3.76 vs. 56.46 ± 4.42, p < 0.05) was significantly improved compared with that before treatment, and the difference was statistically significant. In control group, dyspnoea score (1.89 ± 0.416 vs. 1.82 ± 0.390, p > 0.05) and left ventricular ejection fraction (49.04 ± 6.72 vs. 48.61 ± 7.12, p > 0.05) were slightly improved after treatment, but there was no statistical significance. In terms of safety indicators, patients in the control group were prone to significant blood pressure fluctuation during treatment, and the incidence of IDH was significantly higher than that in the treatment group (75% vs. 0%, p < 0.01), the difference was statistically significant, while the other safety indicators (heart rate change, bleeding and thromboembolic events) showed no statistically significant difference between the two groups.

CONCLUSIONS

Compared with conventional HD, UF combined with HD can safely and effectively reduce water retention in patients with uraemia while avoiding IDH.

Different Interdialytic Intervals and Cardiorespiratory Fitness in Patients Undergoing Hemodialysis

Key Points

This is the first study exploring differences in cardiorespiratory fitness assessed with cardiopulmonary exercise testing between the 2-day and the 3-day interdialytic interval. The 3-day interdialytic interval was associated with further impaired cardiorespiratory fitness. This effect was predominantly driven by excess fluid accumulation during the extra interdialytic day.

Background

Long interdialytic interval in thrice-weekly hemodialysis is associated with excess cardiovascular and all-cause mortality risk. Impaired cardiorespiratory fitness is a strong predictor of mortality in hemodialysis. This study investigated differences in cardiorespiratory fitness assessed with cardiopulmonary exercise testing (CPET) between the end of the 2-day and the 3-day interdialytic interval.

Methods

A total of 28 hemodialysis patients, randomized in two different sequences of evaluation, underwent CPET and spirometry examination at the end of the 2-day and the 3-day intervals. The primary outcome was the difference in oxygen uptake at peak exercise (VO2peak [ml/kg per minute]) assessed with CPET. Volume status was assessed with interdialytic weight gain, lung ultrasound, bioimpedance spectroscopy, and inferior vena cava measurements. A total of 14 age-matched and sex-matched controls were also evaluated. Comparisons of changes in parameters of interest were performed with paired or independent t -tests or relevant nonparametric tests, as appropriate. Bivariate correlation analyses and generalized linear mixed models were used to examine associations between changes in CPET parameters and volume indices.

Results

Hemodialysis patients at the end of both 2-day and 3-day intervals presented lower values in all major CPET parameters than controls. VO2peak (ml/kg per minute) was significantly higher at the end of the 2-day than the 3-day interval (15.2±4.2 versus 13.6±2.8; P < 0.001); the results were similar for VO2peak (ml/min) (1188±257 versus 1074±224; P < 0.001) and VO2peak (% predicted) (58.9±9.2 versus 52.3±8.6; P < 0.001). Numerical but no statistically significant differences were detected in VO2 anaerobic threshold (ml/kg per minute) and VO2 anaerobic threshold (ml/min) between the two time points. Maximal work load (90.1±23.2 versus 79.3±25.1; P < 0.001), exercise duration, heart rate at peak exercise, and oxygen pulse also showed lower values at the end of the 3-day interval. Forced expiratory volume in 1-second levels were similar between the two evaluations. Generalized linear mixed model analysis, including interdialytic weight gain as random covariate, attenuated the observed differences in VO2peak (ml/kg per minute). Changes in bioimpedance spectroscopy–derived overhydration indexes were moderately correlated with changes of VO2peak (ml/kg per minute).

Conclusions

The 3-day interval was associated with further impairment of VO2 at peak exercise. This effect was predominantly driven by excess fluid accumulation during the extra interdialytic day.

Exercise for patients with chronic kidney disease: from cells to systems to function

Chronic kidney disease (CKD) is among the leading causes of death and disability, affecting an estimated 800 million adults globally. The underlying pathophysiology of CKD is complex creating challenges to its management. Primary risk factors for the development and progression of CKD include diabetes mellitus, hypertension, age, obesity, diet, inflammation, and physical inactivity. The high prevalence of diabetes and hypertension in patients with CKD increases the risk for secondary consequences such as cardiovascular disease and peripheral neuropathy. Moreover, the increased prevalence of obesity and chronic levels of systemic inflammation in CKD have downstream effects on critical cellular functions regulating homeostasis. The combination of these factors results in the deterioration of health and functional capacity in those living with CKD. Exercise offers protective benefits for the maintenance of health and function with age, even in the presence of CKD. Despite accumulating data supporting the implementation of exercise for the promotion of health and function in patients with CKD, a thorough description of the responses and adaptations to exercise at the cellular, system, and whole body levels is currently lacking. Therefore, the purpose of this review is to provide an up-to-date comprehensive review of the effects of exercise training on vascular endothelial progenitor cells at the cellular level; cardiovascular, musculoskeletal, and neural factors at the system level; and physical function, frailty, and fatigability at the whole body level in patients with CKD.

Cerebral oxygenation during exercise deteriorates with advancing chronic kidney disease

BACKGROUND

Cognitive impairment and exercise intolerance are common in chronic kidney disease (CKD). Cerebral perfusion and oxygenation play a major role in both cognitive function and exercise execution. This study aimed to examine cerebral oxygenation during a mild physical stress in patients at different CKD stages and controls without CKD.

METHODS

Ninety participants (18 per CKD stage 2, 3a, 3b and 4 and 18 controls) underwent a 3-min intermittent handgrip exercise at 35% of their maximal voluntary contraction. During exercise, cerebral oxygenation [oxyhaemoglobin (O2Hb), deoxyhaemoglobin (HHb) and total haemoglobin (tHb)] was assessed by near-infrared spectroscopy. Indices of microvascular (muscle hyperaemic response) and macrovascular function (carotid intima-media thickness and pulse wave velocity (PWV)) and cognitive and physical activity status were also evaluated.

RESULTS

No differences in age, sex and body mass index were detected among groups. The mini-mental state examination score was significantly reduced with advancing CKD stages (controls: 29.2 ± 1.2, stage 2: 28.7 ± 1.0, stage 3a: 27.8 ± 1.9, stage 3b: 28.0 ± 1.8, stage 4: 27.6 ± 1.5; P = .019). Similar trends were observed for physical activity levels and handgrip strength. The average response in cerebral oxygenation (O2Hb) during exercise was lower with advancing CKD stages (controls: 2.50 ± 1.54, stage 2: 1.30 ± 1.05, stage 3a: 1.24 ± 0.93, stage 3b: 1.11 ± 0.89, stage 4: 0.97 ± 0.80 μmol/l; P < .001). The average tHb response (index of regional blood volume) showed a similar decreasing trend (P = .003); no differences in HHb among groups were detected. In univariate linear analysis, older age, lower estimated glomerular filtration rate (eGFR), Hb, microvascular hyperaemic response and increased PWV were associated with poor O2Hb response during exercise. In the multiple model, eGFR was the only parameter independently associated with the O2Hb response.

CONCLUSIONS

Brain activation during a mild physical task appears to decrease with advancing CKD as suggested by the smaller increase in cerebral oxygenation. This may contribute to impaired cognitive function and reduced exercise tolerance with advancing CKD.

Muscle Oxygenation and Microvascular Reactivity Across Different Stages of CKD: A Near-Infrared Spectroscopy Study

RATIONALE & OBJECTIVE

Previous studies in chronic kidney disease (CKD) showed that vascular dysfunction in different circulatory beds progressively deteriorates with worsening CKD severity. This study evaluated muscle oxygenation and microvascular reactivity at rest, during an occlusion-reperfusion maneuver, and during exercise in patients with different stages of CKD versus controls.

STUDY DESIGN

Observational controlled study.

SETTING & PARTICIPANTS

90 participants (18 per CKD stage 2, 3a, 3b, and 4, as well as 18 controls).

PREDICTOR

CKD stage.

OUTCOME

The primary outcome was muscle oxygenation at rest. Secondary outcomes were muscle oxygenation during occlusion-reperfusion and exercise, and muscle microvascular reactivity (hyperemic response).

ANALYTICAL APPROACH

Continuous measurement of muscle oxygenation [tissue saturation index (TSI)] using near-infrared spectroscopy at rest, during occlusion-reperfusion, and during a 3-minute handgrip exercise (at 35% of maximal voluntary contraction). Aortic pulse wave velocity and carotid intima-media thickness were also recorded.

RESULTS

Resting muscle oxygenation did not differ across the study groups (controls: 64.3% ± 2.9%; CKD stage 2: 63.8% ± 4.2%; CKD stage 3a: 64.1% ± 4.1%; CKD stage 3b: 62.3% ± 3.3%; CKD stage 4: 62.7% ± 4.3%; P=0.6). During occlusion, no significant differences among groups were detected in the TSI occlusion magnitude and TSI occlusion slope. However, during reperfusion the maximum TSI value was significantly lower in groups of patients with more advanced CKD stages compared with controls, as was the hyperemic response (controls: 11.2%±3.7%; CKD stage 2: 8.3%±4.6%; CKD stage 3: 7.8%±5.5%; CKD stage 3b: 7.3%±4.4%; CKD stage 4: 7.2%±3.3%; P=0.04). During the handgrip exercise, the average decline in TSI was marginally lower in patients with CKD than controls, but no significant differences were detected across CKD stages.

LIMITATIONS

Moderate sample size, cross-sectional evaluation.

CONCLUSIONS

Although no differences were observed in muscle oxygenation at rest or during occlusion, the microvascular hyperemic response during reperfusion was significantly impaired in CKD and was most prominent in more advanced CKD stages. This impaired ability of microvasculature to respond to stimuli may be a crucial component of the adverse vascular profile of patients with CKD and may contribute to exercise intolerance.

Cardiorenal syndrome and the association with fitness: Data from a telerehabilitation randomized clinical trial

Aims

To investigate the associations of cardiorespiratory fitness with cardiac, vascular, renal and cardiorenal characteristics in chronic heart failure in a telerehabilitation randomized clinical trial. Secondly, to evaluate the associations of cardiorenal syndrome with the effects of exercise.

Methods and results

Sixty‐nine heart failure patients attended baseline examination, and 61 patients were randomly assigned 1:1 to 3‐month telerehabilitation or control. Data were collected at baseline and 3‐month post‐intervention, including echocardiography and vascular ultrasound, laboratory tests, exercise test with peak oxygen consumption (VO_2peak) measurement and 6‐min walk test (6MWT). Baseline VO_2peak and 6MWT distance was 0.85 mL*min⁻¹*kg⁻¹ lower and 20 m shorter per 10 mL/min/1.73m² lower estimated glomerular filtration rate (both P < 0.001). Heart failure patients with cardiorenal syndrome had 3.5 (1.1) mL*min⁻¹*kg⁻¹ lower VO_2peak and diastolic dysfunction grade 2–3, and elevated filling pressure was >50% more common compared with those without (all P < 0.05). At the 3‐month post‐intervention follow‐up, only the non‐CRS patients in the intervention group increased VO_2peak (0.73 (0.51) mL*min⁻¹*kg⁻¹), whereas VO_2peak in the CRS subpopulation of controls decreased (−1.34 (0.43) mL*min⁻¹*kg⁻¹). Cardiorenal syndrome was associated with a decrease in VO_2peak in CRS patients compared with non‐CRS patients, −0.91 (0.31) vs. 0.39 (0.35) mL*min⁻¹*kg⁻¹ respectively, P = 0.013.

Conclusions

Cardiorenal syndrome was negatively associated with VO_2peak and 6MWT distance in chronic HF, and the associations were stronger than for heart failure phenotypes and other characteristics. The effect of exercise was negatively associated with cardiorenal syndrome. Exercise seems to be as important in heart failure patients with cardiorenal syndrome, and future studies should include CRS patients to reveal the most beneficial type of exercise.