Validity and Reliability of the 6-minute Stepper Test in Patients With Peripheral Artery Disease

Examination of the Validity and Reliability of 6-minute Stepper Test in Patients With Peripheral Artery Disease

Hemodynamic dysfunction and decreased blood flow to the extremities negatively affect patients' muscle oxygenation, balance, claudication pain, lower extremity muscle strength, and arterial stiffness. These negatively affect patients' exercise capacity. The six-minute stepper test (6 MST) is a simple, low-cost, and minimal space requirement assessment method used to evaluate functional exercise capacity and is known to be valid and reliable for various pulmonary and cardiovascular diseases. However, it is not known whether the 6 MST is valid and reliable in assessing functional exercise capacity in patients with PAD. It is known that muscle oxygen levels, balance levels, intermittent claudication, lower extremity muscle strength, and arterial stiffness have negative effects on exercise capacity. However, the extent to which these variables affect the 6 MST is unknown. The primary aim is to examine the validity and reliability of the 6 MST in patients with PAD. The secondary aim is to evaluate arterial stiffness, muscle oxygen levels, intermittent claudication, static and dynamic balance levels, lower extremity muscle strength, and examine their effects on the 6 MST.

Peripheral artery disease (PAD) is a common condition that carries a high risk of cardiovascular morbidity and mortality. PAD is an atherosclerotic process that causes occlusion of peripheral arteries. Hemodynamic dysfunction and decreased blood flow to the extremities negatively affect patients' muscle oxygenation, balance, claudication pain, lower extremity muscle strength, and arterial stiffness. These negatively affect patients' exercise capacity and increase the risk of mortality. To prevent this, patients' exercise capacity should be properly assessed and increased with an appropriate exercise programme. Several tests are available to assess exercise capacity. The cardiopulmonary exercise test (CPET) is the gold standard method for measuring exercise capacity. However, due to its high cost, the need for qualified personnel and complex equipment, it cannot be used in every clinic. Therefore, field tests have been developed to assess functional exercise capacity. The six-minute stepper test (6 MST) is a simple, low-cost, and minimal space requirement assessment method used to evaluate functional exercise capacity and is known to be valid and reliable for various pulmonary and cardiovascular diseases. However, it is not known whether the 6 MST is valid and reliable in assessing functional exercise capacity in patients with PAD. It is known that muscle oxygen levels, balance levels, intermittent claudication, lower extremity muscle strength, and arterial stiffness have negative effects on exercise capacity. However, the extent to which these variables affect the 6 MST is unknown. If this is known, clinicians and researchers will interpret this exercise test more carefully, and its use in individuals with PAD will become more effective. Therefore, the primary aim is to examine the validity and reliability of the 6 MST in patients with PAD. The secondary aim is to evaluate arterial stiffness, muscle oxygen levels, intermittent claudication, static and dynamic balance levels, lower extremity muscle strength, and examine their effects on the 6 MST. A minimum of 24 individuals with PAD will be included in the study. Patients' demographic and clinical information will be recorded. Pulmonary function (spirometry), PAD classification (Fonteine classification and Rutherford classification), and comorbidity (Charlson Comorbidity Index) will be assessed and recorded. The gold standard methods for assessing exercise capacity for structural validity, CPET and the 6-minute walk test (6 MWT), will be performed. For reliability, 6 MST will administered a second time at 24-hour intervals. Arterial stiffness (pulse wave analysis and brachial and aortic pulse wave velocity), muscle oxygenation (near-infrared spectrometer), peripheral muscle strength (dynamometer), static balance (Kinvent PLATES v3), dynamic balance (timed up and go test), intermittent claudication (Walking Impairment Questionnaire and Borg Scale) will assessed. The results will be analysed and interpreted using appropriate statistical analysis methods.

Inclusion Criteria:

• Diagnosed with peripheral artery disease by the Department of Cardiovascular Surgery,
• Ankle-brachial index (ABI) ≤1.40 or exercise ABI ≤0.73 or diagnosed with calcified vascular response, in remission and under follow-up,
• Stable,
• Ages between 18 and 80,
• Patients who volunteer to participate in the study will be included.

Exclusion Criteria:

• Patients will be excluded if they have:
• Previously underwent ischaemic amputation,
• Unstable coronary artery disease,
• Uncontrolled Diabetes Mellitus,
• Pulmonary disease,
• Acute infection,
• Weight >110 kg because it is the upper limit of the stepper device,
• Contraindications to exercise testing per the American Sports Medicine Association,
• Pregnant and breastfeeding women,
• Patients with PAD who have undergone major surgery or had a myocardial infarction within the last 3 months.