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.
(C) 2014 American College of Sports Medicine