Relationship between walking capacity and ambulatory blood pressure in patients with intermittent claudication

Is the Walking Impairment Questionnaire a surrogate marker of 6-minute walking test performance in patients with peripheral artery disease with different degrees of claudication symptoms?

AIM

To analyze the associations between the Walking Impairment Questionnaire (WIQ) and 6-minute walk test (6MWT) in absolute or relative performance in patients with peripheral artery disease (PAD) and different degrees of claudication symptoms.

METHODS

Two hundred and sixty-seven patients with PAD and claudication symptoms participated in the study. All patients underwent 6MWT and WIQ tests. Patients were divided into tertile groups according to their 6MWT performance (1st tertile = severe, 2nd = moderate, 3rd = mild). Multiple linear regression was performed to investigate the association between WIQ scores and the achievement of expected performance in the 6MWT.

RESULTS

Claudication onset distance and time, total walking distance, and the percentage of the predicted values had a significant weak correlation ( P  < 0.01) with WIQ scores (distance, speed, and stair-climbing capacity). The correlations for almost all variables were slightly higher in the 1st tertile compared with the 2nd and 3rd tertiles (i.e. WIQ-distance and Claudication onset time, r  = 0.25 and 0.12, WIQ-distance and Claudication onset distance, r  = 0.34 and 0.18; WIQ-distance and total walking distance, r  = 0.23 and 0.18, respectively). Multilinear regression confirmed a slightly superior relationship in the 1st tertile compared with the 2nd tertile (i.e. WIQ-distance and Claudication onset time, R2  = 0.24 and R2  = 0.01; WIQ-distance and Claudication onset distance, R2  = 0.25 and R2  = 0.03, respectively).

CONCLUSIONS

WIQ is weakly associated with absolute and relative 6MWT performance in patients with PAD. Despite slightly better correlations in patients with severe claudication symptoms, WIQ scores must be used with care as a surrogate marker of 6MWT performance in this group.

Longitudinal Changes in Physical Activity Levels and Cardiovascular Risk Parameters in Patients with Symptomatic Peripheral Artery Disease

BACKGROUND

Previous cross-sectional studies have demonstrated that physical activity is associated with lower cardiovascular risk in patients with peripheral artery disease (PAD). However, it is not possible to establish causality, and longitudinal design studies are required.

OBJECTIVE

To analyze the changes in cardiovascular risk parameters and physical activity levels after a 2-year follow-up in patients with symptomatic PAD.

METHODS

This study started in 2015. In the first phase, 268 patients were included. In the second phase, after 2 years (median = 26 months), 72 patients were re-evaluated. Cardiovascular risk parameters, such as blood pressure, cardiac autonomic modulation, and arterial stiffness, and physical activity levels were measured at baseline and after 2 years of follow-up. Association among delta changes (values from follow-up - baseline) in physical activity and cardiovascular parameters were analyzed by multiple linear regression. The significance level was set at p < 0.05.

RESULTS

Patients reduced their total physical activity levels compared to baseline (baseline = 2257.6 ± 774.5 versus follow-up = 2041 ± 676.2 min/week, p = 0.001). After follow-up, ankle-brachial index (0.62 ± 0.20 versus 0.54 ± 0.20, p = 0.003), and standard deviation of all RR intervals (43.4 ± 27.0 versus 25.1 ± 13.4 ms, p < 0.001) were lower, whereas carotid-femoral pulse wave velocity was higher (9.0 ± 3.0 versus 10.7 ± 3.4 m/s, p = 0.002) compared to baseline values. We did not observe any association among delta values of physical activity levels and cardiovascular risk parameters.

CONCLUSION

Patients with PAD had reduced physical activity levels and impaired cardiovascular risk parameters during 2-year follow-up.

Effects of arm-crank exercise on cardiovascular function, functional capacity, cognition and quality of life in patients with peripheral artery disease: Study protocol for a randomized controlled trial

Background

Arm-crank exercise training (ACT) is an alternative exercise strategy for patients with symptomatic peripheral artery disease (PAD) due to the attenuation of pain symptoms during the exercise, as well as the benefits to functional capacity.

Purpose

The aim of this study is to describe the study protocol to analyze the effects of ACT exercise on cardiovascular function, functional capacity, cognition and quality of life in patients with symptomatic PAD.

Methods

This is a three-armed randomized, prospective, single-blind data collection, single-center, controlled study enrolling 45 patients with symptomatic PAD who will be randomized into 3 intervention groups: walking training (WT), ACT and control group. The WT and ACT will perform 2 sessions/week, 15 to 10 sets of 2 to 5 minutes at values of 13 to 15 on the Borg scale. Before and after 12 weeks of intervention, cardiovascular function (ambulatory blood pressure, office blood pressure, central blood pressure, heart rate variability, arterial stiffness and vascular function), functional capacity (six-minute walk test, 2 minute step test, handgrip test, Walking impairment questionnaire, Walking estimated limitation calculated by history, Baltimore activity scale for intermittent claudication, and short physical performance battery), cognition (executive function and memory), and quality of life (vascular quality of life questionnaire and World Health Organization Quality of Life) will be assessed.

Results

This is the first trial to evaluate the effects of ACT on regulatory mechanisms of the cardiovascular system in PAD patients. If the results are as expected, they will provide evidence the ability of ACT to promote cardiovascular benefits in the symptomatic PAD population.

Validity and reliability of 2-min step test in patients with symptomatic peripheral artery disease

BACKGROUND

Although 2-min step test (2MST) has been useful in general population, no study has investigated its validity in patients with peripheral artery disease (PAD).

OBJECTIVE

To analyze the validity and reliability of the 2MST in patients with PAD and claudication symptoms.

METHODS

Twenty-four patients with PAD and claudication symptoms were recruited and performed the 2MST comparing it to the six-minute walk test (6MWT). Test performance, step indicators, and heart rate were measured during the test. Validity was verified using Pearson correlation between the performance of 2MST (number of steps) and 6MWT (distance and number of steps). The reliability was analyzed by the intraclass correlation coefficient and by the limits of agreement of Bland and Altman.

RESULTS

A similar performance was observed between the two 2MST (65 ± 10 steps vs. 66 ± 10 steps, p = 0.43) with a significant intraclass coefficient correlation of 0.945. The bias between tests was of 0.79 steps with the limits of agreement between -9.6 and 11.2 steps. The 90% minimum detectable difference was 3.2 steps. The number of steps in 2MST was significantly correlated with the number of steps in 6MWT (r = 0.55, p<0.01). However, the number of steps in 2MST did not correlate with distance in the 6MWT (r = 0.26, p = 0.23). The peak heart rate was lower in 2MST compared to 6MWT (p<0.05).

CONCLUSION

The 2MST present adequate reliability and validity in patients with symptomatic PAD.

Functional and Cardiovascular Measurements in Patients With Peripheral Artery Disease: COMPARISON BETWEEN MEN AND WOMEN

PURPOSE

To compare functional and cardiovascular variables of men and women with peripheral artery disease (PAD).

METHODS

This observational, cross-sectional study included 67 women and 144 men (age 66 ± 9 and 67 ± 10 yr, respectively) with PAD. Patients were submitted to a clinical evaluation, 6-min walk test (6MWT) and cardiovascular evaluation, including blood pressure, arterial stiffness variables, and heart rate variability.

RESULTS

Women had lower claudication onset distance (P = .033) and 6MWT distance (P < .001), and similar percentage of the predicted 6MWT distance (P > .05). Women had higher pulse pressure (P = .002), augmentation index (P < .001), augmentation index corrected by 75 bpm (P < .001), and brachial and central systolic blood pressure (P = .041 and P = .029). Diastolic blood pressure, pulse wave velocity, and heart rate variability were similar between sexes (P > .05).

CONCLUSION

Although predicted 6MWT performance was similar between sexes, women had higher blood pressure and wave reflection variables compared with men. Interventions to reduce blood pressure and wave reflection should be emphasized in women with PAD.

Walking Training Improves Ambulatory Blood Pressure Variability in Claudication

Fundamento:

O treinamento de caminhada (TC) melhora a capacidade de caminhar e reduz a pressão arterial (PA) clínica em pacientes com doença arterial periférica (DAP), mas seus efeitos na PA ambulatorial permanecem desconhecidos.

Objetivo:

Investigar o efeito de 12 semanas de TC na PA ambulatorial e sua variabilidade em pacientes com DAP.

Métodos:

Trinta e cinco pacientes do sexo masculino com DAP e sintomas de claudicação foram alocados aleatoriamente em dois grupos: controle (n = 16, 30 min de alongamento) e TC (n = 19, 15 séries de 2 minutos de caminhada na frequência cardíaca em que ocorreu limiar de dor intercalados por 2 minutos de repouso em pé). Antes e depois de 12 semanas, a PA ambulatorial de 24 horas foi avaliada. Os índices de variabilidade da PA ambulatorial avaliados em ambos os momentos incluíram o desvio-padrão de 24 horas (DP₂₄), o desvio-padrão ponderado de vigília e sono (DP_vs) e a variabilidade real média de 24 horas (VRM₂₄). Os dados foram analisados por ANOVAs mistas de dois fatores, considerando significativo P<0,05.

Resultados:

Após 12 semanas, nenhum dos grupos apresentou alterações na PA de 24 horas, vigília e sono. O TC diminuiu as variabilidades da PA sistólica e média (PA sistólica – 13,3 ± 2,8 vs 11,8 ± 2,3; 12,1 ± 2,84 vs 10,7 ± 2,5; e 9,4 ± 2,3 vs 8,8 ± 2,2 mmHg; PA média – 11,0 ± 1,7 vs 10,4 ± 1,9; 10,1 ± 1,6 vs 9,1 ± 1,7; e 8,0 ± 1,7 vs 7,2 ± 1,5 mmHg para DP₂₄, DPvs e VRM₂₄, respectivamente). Nenhum dos grupos apresentou mudanças significantesnos índices de variabilidade da PA diastólica após 12 semanas.

Conclusões:

O TC não altera os níveis ambulatoriais da PA, mas diminui a sua variabilidade em pacientes com DAP. Essa melhora pode ter um impacto favorável no risco cardiovascular de pacientes com DAP sintomática. (Arq Bras Cardiol. 2021; 116(5):898-905)

Expanding the Use of Six-Minute Walking Test in Patients with Intermittent Claudication

BACKGROUND

Six-min walking test (6MWT) has been widely in patients with symptomatic peripheral artery disease (PAD) to quantify the walking impairment and the efficacy of different therapeutic interventions. Despite the aforementioned usefulness of 6MWT for PAD, the information provided by this test goes beyond the meters walked. The aim of this study was to describe the relative values of 6MWT and body weight-walking distance product (DW) in patients with symptomatic PAD.

METHODS

Two hundred twenty-seven patients with symptomatic PAD participated in the study. The 6MWT was performed and absolute and claudication distances were obtained. The results of 6MWT were then relativized and expressed as a percentage of a healthy subject. DW was obtained by the product of 6MWT distance by weight. In both sexes, the relative 6MWT ranged from 57% to 64%.

RESULTS

Absolute 6MWT total distance (P < 0.001) was lower in women than in men, whereas the relative 6MWT total distance was similar between sexes (P = 0.398). The absolute and relative 6MWT total distance were similar among age categories (P > 0.072). The DW was higher in men than in women (P < 0.05). In addition, in women, DW was higher in younger group than in other age groups (P < 0.05).

CONCLUSIONS

Patients with symptomatic PAD achieve less than 70% of the distance achieved by an age-matched healthy subject. In patients with symptomatic PAD, the relative values of 6MWT total distance are similar between sexes and among different age groups, whereas DW are influenced by age and sex.

Are cardiovascular function and habitual physical activity levels similar in patients with classic and atypical claudication symptoms? A cross-sectional study

Objective

To analyze the impact of the different types of exertional leg pain on cardiovascular function, functional capacity, and habitual physical activity levels in patients with peripheral arterial disease.

Methods

In this cross-sectional study, 124 patients with symptomatic peripheral arterial disease were included. Exertional leg pain was evaluated using the San Diego Claudication Questionnaire. Subsequently, patients were categorized into two groups according to their exertional leg pain: atypical leg pain (non-calf pain and atypical calf pain, n = 31) and intermittent claudication (classic intermittent claudication symptoms, n = 93). Cardiovascular function (blood pressure, heart rate, arterial stiffness, and heart rate variability), functional capacity (6-min walk distance, handgrip strength, and short physical performance battery), and habitual physical activity levels were measured.

Results

Functional capacity and physical activity levels were similar between patients with atypical leg pain and symptoms of intermittent claudication. However, patients with classic intermittent claudication symptoms presented higher central systolic blood pressure ( P = 0.028) and arterial stiffness (augmentation index and pulse pressure; P ≤ 0.001 and 0.019, respectively) compared to patients with atypical leg pain.

Conclusion

The type of exertional leg pain does not influence functional capacity and habitual physical activity levels in patients with peripheral arterial disease. However, patients with classic intermittent claudication symptoms present impaired cardiovascular function compared to patients with atypical leg pain.

In peripheral artery disease, diabetes is associated with reduced physical activity level and physical function and impaired cardiac autonomic control: A cross-sectional study

BACKGROUND

Diabetes has been considered a major risk factor for peripheral artery disease (PAD). The effect of diabetes on daily physical activity level and cardiovascular function in PAD patients is poorly known.

OBJECTIVE

To analyze the effect of diabetes on physical activity level, physical function and cardiovascular health parameters in patients with PAD and claudication symptoms.

METHODS

Cross-sectional study of 267 PAD patients, 146 without and 121 with diabetes. Physical activity levels were objectively measured by using an accelerometer, and time spent in sedentary (0-100 counts/min), light (101-1040 counts/min) and moderate to vigorous (≥1041 counts/min) physical activity was obtained. Physical function assessment included the 6-min walk test, handgrip strength test and short physical performance battery. Cardiovascular health parameters measured were brachial blood pressure, heart rate variability, and arterial stiffness.

RESULTS

Diabetic PAD patients spent more time in sedentary behavior (P=0.001, effect size [ES] 0.234) and less time in light (P=0.003, ES=0.206) and moderate-to-vigorous physical activity (P<0.001, ES=0.258) than non-diabetic PAD patients. Diabetic PAD patients presented lower 6-min walk distance (P=0.005, ES=0.194) and impaired cardiac autonomic modulation (standard deviation of all NN intervals [SDNN], P<0.001, ES=0.357; square root of the mean of the sum of the squares of differences between adjacent NN intervals [RMSSD], P<0.001, ES=0.280; and NN50 count divided by the total number of all NN intervals [pNN50], P<0.001, ES=0.291) as compared with non-diabetic PAD patients. After adjustment for confounders, diabetes remained associated with sedentary behavior (P=0.011), light (P=0.020) and moderate-to-vigorous physical activity (P=0.008), 6-min walk distance (P=0.030), SDNN (P<0.001), RMSSD (P=0.004), and PNN50 (P=0.004).

CONCLUSION

Diabetic PAD patients presented lower physical activity level, reduced physical function and impaired autonomic modulation as compared with non-diabetic PAD patients.

Cardiac Autonomic Modulation Is Associated with Arterial Stiffness in Patients with Symptomatic Peripheral Artery Disease

BACKGROUND

The objective of this study was to analyze the association between cardiac autonomic modulation and arterial stiffness in patients with peripheral artery disease (PAD).

METHODS

This cross-sectional study included one hundred fourteen patients with symptomatic PAD (67.5% men; 65 ± 7 years; body mass index: 26.8 ± 4.5 kg/m²). Heart rate variability (HRV) was measured within time (standard deviation of all RR intervals [beat to beat heart interval] [SDNN], root mean square of the successive differences between adjacent normal RR intervals [RMSSD], and the proportion of successive RR intervals that differed by more than 50 msec [pNN50]) and frequency (low frequency [LF] and high frequency [HF]) domains. Arterial stiffness was assessed by carotid-femoral pulse wave velocity (cfPWV). Crude and adjusted linear regression analyses examined the relationship between HRV and cfPWV.

RESULTS

Nonsignificant crude associations were identified among cfPWV and RMSSD (P = 0.181), SDNN (P = 0.105), pNN50 (P = 0.087), LF (P = 0.376), HF (P = 0.175), and LF/HF ratio (P = 0.426). After adjustments for age, sex, smoking, body mass index, ankle-brachial index, and use of beta-blockers, significant associations were identified among cfPWV and RMSSD (P = 0.037), SDNN (P = 0.049), and pNN50 (P = 0.049).

CONCLUSIONS

Cardiac autonomic modulation was significantly associated with arterial stiffness in patients with PAD after adjustment for confounding factors. This relationship may contribute to the enhanced cardiovascular disease risk for PAD patients and provides a target for strategies to improve patient clinical outcomes.

Relationship between gait speed and physical function in patients with symptomatic peripheral artery disease

OBJECTIVE

The aim of the study was to analyze the relationship between gait speed and measurements of physical function in patients with symptomatic peripheral artery disease (PAD).

METHODS

One hundred sixty-nine patients (age 66.6±9.4 years) with symptomatic PAD were recruited. Usual and fast gait speeds were assessed with a 4-meter walk test. Objective (balance, sit-to-stand, handrip strength, and six-minute walk test) and subjective (WIQ - Walking Impairment Questionnaire and WELCH - Walking Estimated-Limitation Calculated by History) measurements of physical function were obtained. Crude and adjusted linear regression analyses were used to confirm significant associations.

RESULTS

Usual and fast gait speeds were significantly correlated with all objective and subjective physical function variables examined (r<0.55, p<0.05). In the multivariate model, usual gait speed was associated with six-minute walking distance (β=0.001, p<0.001), sit-to-stand test score (β=-0.005, p=0.012), and WIQ stairs score (β=0.002, p=0.006) adjusted by age, ankle brachial index, body mass index, and gender. Fast gait speed was associated with six-minute walking distance (β=0.002, p<0.001), WIQ stairs score (β=0.003, p=0.010), and WELCH total score (β=0.004, p=0.026) adjusted by age, ankle brachial index, body mass index, and gender.

CONCLUSION

Usual and fast gait speeds assessed with the 4-meter test were moderately associated with objective and subjective measurements of physical function in symptomatic PAD patients.

Calf Muscle Oxygen Saturation during 6-Minute Walk Test and Its Relationship with Walking Impairment in Symptomatic Peripheral Artery Disease

BACKGROUND

Impaired microcirculation is associated with poor walking capacity in symptomatic peripheral artery disease (PAD) patients during treadmill test; however, this test does not simulate the efforts of daily walking of these patients. Thus, the aim of the study was to describe the microcirculation responses during a 6-minute walk test (6MWT) and to analyze the relationship between microcirculation indicators and walking impairment in symptomatic PAD patients.

METHODS

Thirty-four patients were included (mean age = 67.6 ± 11.2 years). Their clinical characteristics were collected, and they performed a 6MWT, in which the initial claudication distance (ICD) and total walking distance (TWD) were recorded. During and after the 6MWT, calf muscle oxygen saturation (StO₂) parameters were monitored continuously to measure microcirculation behavior. The association between calf muscle StO₂ parameters and walking impairment were analyzed by Pearson or Spearman correlations.

RESULTS

Walking impairment was not associated with any StO₂ parameters during exercise. In contrast, after 6MWT, recovery time of StO₂ (r = -0.472, P = 0.008) and recovery time to maximal StO₂ (r = -0.402, P = 0.019) were negatively correlated with ICD. Furthermore, the distance walked under claudication symptoms (ΔTWD-ICD) was positively correlated with recovery time to maximal StO₂ (r = 0.347, P = 0.048).

CONCLUSIONS

In symptomatic PAD patients, shorter ICD values during a 6MWT are associated with a delayed recovery in calf muscle StO₂ after exercise. Calf muscle StO₂ parameters decrease subtly during 6MWT, suggesting that the degree of ischemia in the calf muscle during ground walking, simulating efforts of the daily walking, is relatively low.