Clinical Predictors of Ventilatory Threshold Achievement in Patients with Claudication

Abstract

Purpose Ventilatory threshold (VT) is considered a clinically important marker of cardiovascular function in several populations, including patients with claudication, as it is related to walking capacity and hemodynamics. The purpose of this study was to identify clinical predictors for the VT achievement in intermittent claudication patients. Methods One hundred seventy-seven (n=177) patients with intermittent claudication performed a progressive graded cardiopulmonary treadmill test until maximal claudication pain. Oxygen uptake (VO2) was continuously measured during the test and afterwards VT was visually detected. Clinical characteristics, demographic data, comorbid conditions, and cardiovascular risk factors were obtained. Patients who achieved and did not achieve VT were compared, as well as the workload that VT occurred in the former group. Results VT was achieved in 134 patients (76%) and the mean VO2 at VT for these patients was 10.8 ± 2.4 mL.kg−1.min−1. Patients who did not achieve VT presented lower ankle brachial index (ABI), claudication onset time, peak walking time, and peak VO2, and the proportion of women was higher compared to patients who achieved VT (p<0.05). Multiple linear regression analysis identified that sex (b=0.25, p=0.002), body mass index (b=−0.18, p=0.025), peak walking time (b=0.17, p=0.044), and ABI (b=0.23, p=0.006) were predictors of the VO2 at VT. Conclusion Forty-three patients (24%) with intermittent claudication did not achieve the VT and these patients were mostly women and those with greater severity of disease. Moreover, in those who reached VT, the predictors of poor VT were female sex, high body mass index, low peak walking time, and low ABI.

Skeletal muscle capillary density is related to anaerobic threshold and claudication in peripheral artery disease

“…Several investigations describe AT measures in the PAD population. [20][21][22][23][24][25] However, only one has reported a (positive) relationship between oxygen consumption at AT and initial claudication distance in patients with PAD. 20 In the work of others, AT occurs at a greater relative workload in patients with PAD compared to control subjects; suggesting a metabolic abnormality in muscle oxygen kinetics during exercise.…”

Validation of a Brazilian Portuguese Version of the Walking Estimated-Limitation Calculated by History (WELCH)

“…Walking capacity has been used as an important clinical outcome in patients with IC 9 , 10 , and the walking tests, including the graded treadmill test, has been considered the gold standard for this assessment. 11 , 12 However, because walking tests are more time consuming and require adequate facilities, they are not often used in the clinical setting.…”

Intensidade de Exercício durante o Teste de Caminhada de 6 Minutos em Pacientes com Doença Arterial Periférica

“…Em pacientes com DAP sintomática, o LV está associado à tolerância à caminhada e à gravidade da doença. 9 , 10 Neste estudo, 60% dos pacientes alcançaram o LV no teste de caminhada de 6 minutos, indicando que, para a maioria dos pacientes com DAP sintomática, a caminhada em solo é um exercício de intensidade relativamente alta. Isso poderia explicar parcialmente os níveis mais baixos de atividade física diária e o maior tempo sedentário desses pacientes.…”

“…8 Em pacientes com DAP sintomática, um LV mais baixo está associado a menor tolerância à caminhada e maior gravidade da doença. 9 , 10 Além disso, o LV tem mais probabilidade de ser alcançado antes do início da dor de claudicação. 11 , 12 …”

“…8 In symptomatic PAD patients, lower VT is associated with lower walking tolerance and greater disease severit. 9 , 10 In addition, VT is most likely to be achieved before the onset of claudication pain. 11 , 12 …”