Exercise testing as a screening measure for ability to walk with aprosthesis after transfemoral amputation due to peripheral vascular disease

Purpose: To establish at which exercise-power level is the vascular response, as measured by oxygen uptake, closest to the response during the 6-min walk test (6MWT) in people after lower-limb amputation due to peripheral vascular disease (PVD). Method: A prospective exploratory cohort study was conducted. 6MWT and exercise testing using a hand-wheel ergometer (starting at 10W and increasing the workload by 10W) were performed in 101 consecutively recruited participants after transfemoral amputation due to PVD. Agreement of oxygen uptake during 6MWT and exercise testing was compared between the groups defined by the exercise-power level reached. Results: Linear regression through origin with Chow test for comparing slopes indicated that oxygen uptake at 30W agreed more with 6MWT than at 20, 40 or 50W. Analyses of observed differences (one-way ANOVA with post-hoc tests, Jonckheere-Terpstra test) confirmed 30W to be the recommendable threshold. Conclusions: At the level of 30W, the oxygen uptake during the exercise was the closest to the 6MWT, so we estimated that to be the minimum required level for walking using a prosthesis after transfemoral amputation due to PVD.