Extending the range of treadmill testing for patients with intermittent claudication

Area of Science:

• Cardiovascular Medicine
• Exercise Physiology
• Biomedical Engineering

Background:

• Peripheral arterial disease (PAD) significantly impacts patient mobility and quality of life.
• Accurate assessment of walking distance is essential for evaluating PAD severity and treatment efficacy.
• Current standard treadmill protocols may not suit all patients, necessitating alternative evaluation methods.

Purpose of the Study:

• To develop and validate methods for estimating walking distance in PAD patients using modified treadmill protocols.
• To enable accurate prediction of walking distance measured on a standard protocol from protocols with lower or higher workloads.

Main Methods:

• Included PAD patients with absolute claudication distances (ACD) <500 m or 1000-1600 m.
• Developed four graded treadmill protocols with varying workloads (lower and higher than standard).
• Utilized orthogonal regression analysis to predict standard protocol walking distances from modified protocols, assessing reliability via intraclass correlation and coefficient of variation.

Main Results:

• Feasibility and reliability of two modified protocols (2.0 km·h⁻¹, 2% increase every 2 min and 4.4 km·h⁻¹, 2% increase every minute) were comparable to the standard protocol.
• Prediction of walking distance on the standard protocol using the new protocols showed a coefficient of variation (22%-25%) similar to test-retest variability.
• Forty-three patients with ACD <500 m and 23 patients with ACD 1000-1600 m were included.

Conclusions:

• Walking distance measured using modified treadmill protocols can accurately estimate distances obtained from a standard protocol.
• These findings support the use of lower or higher workload protocols for evaluating PAD patients' walking capacity.
• This offers a flexible approach to assessing walking limitations in peripheral arterial disease.