The prognostic value of impaired walking distance on long-term outcome in patients with known or suspected peripheral arterial disease

Objectives: To assess the predictive value of walking distance after an exercise test on long-term outcome in patients with normal and impaired ankle-brachial index (ABI).

Design: A total of 2191 patients with known or suspected peripheral arterial disease (PAD), who were referred for a single-stage treadmill exercise test to diagnose or evaluate their PAD, were enrolled in an observational study between 1993 and 2006.

Materials and methods: They were divided into two groups: normal ABI (>or=0.90) and impaired ABI (<0.90). Walking distance was divided into quartiles (no (reference), mild, moderate or severe impairment).

Results: In patients with normal ABI, severe walking distance was, after adjustment, associated with higher mortality risk (hazard ratio (HR): 2.60 (range: 1.16-5.78)). In patients with impaired ABI, all walking distance impairment quartiles were associated with higher mortality (mild HR: 1.26 (range: 0.95-1.67), moderate HR: 1.52 (range: 1.13-2.05) and severe HR: 1.69 (range: 1.26-2.27)). Furthermore, comparable associations were observed between all walking distance quartiles, cardiac death or major adverse cerebrovascular and cardiac events.

Conclusions: Our study illustrated that walking impairment is a strong prognostic indicator of long-term outcome in patients with impaired and normal ABI, which should be a warning sign to physicians to monitor these patients carefully and to provide them optimal treatment.