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

Not yet recruiting

• Conditions: Peripheral Artery Disease (PAD)

• Registration Number: NCT07169045
• Lead Sponsor: Gazi University

Brief Summary

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.

Detailed Description

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.

Study Timeline

• Status Verified: 2025-09
• Study First Submitted: 2025-09-04
• Study First Submitted QC: 2025-09-04
• Last Update Submitted: 2025-09-04
• Study First Posted: 2025-09-11
• Last Update Posted: 2025-09-11
• Study Start: 2025-09-24
• Primary Completion: 2026-07-24
• Study Completion: 2026-07-24

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 24

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.

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
6-minute Stepper Test	Trough study completion, an average of 1 year	The test will performed using the previously defined Borel et al. criteria and the adaptation of the ATS/ERS 6 MWT criteria. For the test, a standard resistance 'Stepper' device will used, positioned 20 cm above the ground. To enable the patient to receive support if they lose their balance, the stepper device will placed 10 cm away from a straight wall edge. Patients will asked to take as many steps as possible during 6 minutes. The test will be conducted for 2 minutes first for the patient to learn, and then 6 minutes of testing will be conducted after a 3-minute rest period. 6 MST will be re-applied to patients 24 hours later using the same protocol for reliability analysis.
Cardiopulmonary Exercise Test	Trough study completion, an average of 1 year	CPET is the gold standard method used to assess maximal exercise capacity. For this reason, 6 MST will used to examine structural validity. CPET will be performed using a gradually increasing workload protocol with breath-by-breath measurement on a treadmill. Electrocardiography (ECG) assessment during the test will be performed using a 12-lead ECG trace. Oxygen consumption and metabolic equivalent will be measured.
6-minute Walk Test	Trough study completion, an average of 1 year	The 6 MWT is a valid and reliable submaximal exercise test for patients with peripheral arterial disease. 6 MWT will be applied to examine the structural validity of 6 MST. It will be carried out in accordance with ATS criteria.The walking distance will be recorded in two ways: in metres and as a percentage of the expected walking distance.

Secondary Outcome Measures

Name	Time	Method
Pulmonary function test	Trough study completion, an average of 1 year	Pulmonary function will be evaluated with the spirometry. Dynamic lung volume measurements will be made according to American Thoracic Society and European Respiratory Society criteria. With the device, forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), FEV1/FVC, peak expiratory flow rate (PEF), and flow rate 25-75% of forced expiratory volume (FEV25-75%) will be measured.
Classification Systems for Peripheral Artery Disease	Trough study completion, an average of 1 year	It will be performed using the Fontaine and Rutherford classification systems. According to the Fontaine classification system, peripheral arterial disease in individuals is assessed as stage I: asymptomatic disease, stage Ia: mild claudication, stage Ib: moderate-severe claudication, stage II: pain at rest, stage IV: ulceration or gangrene. According to the Rutherford classification system, it is classified as follows: 0: Asymptomatic, 1: Mild claudication, 2: Moderate claudication, 3: Severe claudication, 4: Ischemic rest pain, 5: Minor tissue loss, 6: Major tissue loss.
Charlson Comorbidity Index	Trough study completion, an average of 1 year	This index identifies and defines 19 comorbid chronic diseases accompanying patients' primary diseases and determines the mortality risk. The total score obtained from the index ranges from 0 to 37.
Static Balance	Trough study completion, an average of 1 year	Static balance assessment will be performed using Kinvent PLATES v3. On the PLATES, with eyes open and closed, three repetitions will be performed first on double leg and then single leg. The average of the three tests will be used for analysis.
Arterial Stiffness	Trough study completion, an average of 1 year	Arterial stiffness will be assessed using the SphygmoCor® XCEL device. The patient's peripheral blood pressure will be measured by partially inflating the cuff on the brachial artery. Then, to assess carotid PWV, carotid pulse waves will be measured with a tonometer. A cuff will be placed on the femoral area to measure femoral PWV. The device will measure carotid-femoral artery PWV, pulse transit time, augmented index (Aix) values.
Peripheral Muscle Oxygenation	Trough study completion, an average of 1 year	CPET and the second time applied 6 MST before, during, and recovery, the patients' dominant side gastrocnemius and quadriceps femoris muscles' oxygen percentage (SmO2%), oxyhaemoglobin (O2Hb) and deoxyhaemoglobin (HHb) levels, the difference between O2Hb and HHb (HbDiff), and total haemoglobin concentration (THb) levels will be measured using a near-infrared spectrometer (NIRS) device.
Peripheral Muscle Strength	Trough study completion, an average of 1 year	Patients' knee extensor and plantar flexor muscle strength will be assessed using the Kinvent K-Push dynamometer.
Dynamic Balance	Trough study completion, an average of 1 year	Dynamic balance will be assessed using the timed up and go test. The duration will be recorded in seconds. The test will be repeated three times, and the best time will be used in the analysis.
Walking Impairment Questionnaire (WIQ)	Trough study completion, an average of 1 year	The 21-item 'Walking Impairment Questionnaire (WIQ)' developed by Regensteiner et al. (1995) will be used in its Turkish adaptation. WIQ consists of the parameters of claudication, differential diagnosis, walking distance, walking speed, and the ability to climb stairs. A high score indicates high performance.
Intermittent Claudication	Trough study completion, an average of 1 year	Intermittent claudication will recorded using the modified Borg scale. The total number of steps at the end of the 6 MST, the time when claudication pain began, the number of steps at which claudication pain began, the duration of the test in minutes, and whether absolute claudication pain was present will recorded. The onset time and distance of intermittent claudication and absolute claudication will be recorded in the CPET and 6 MWT tests.
Fatigue Perception	Trough study completion, an average of 1 year	Fatigue perception will be evaluated with Modified Borg Scale. The Modified Borg scale is a subjective scale that scores 0-10 for breathlessness and fatigue at rest and/or during activity. The lowest 0 points "not at all" the highest 10 points "very severe" means fatigue. The perception of fatigue will be assessed before, during, and recovery of the 6 MST, CPET, and 6 MWT.
Dyspnea Perception	Trough study completion, an average of 1 year	Dyspnea perception will be measured with Modified Borg Scale. The Modified Borg scale is a subjective scale that scores 0-10 for breathlessness and fatigue at rest and/or during activity. The lowest 0 points "not at all" the highest 10 points "very severe" means shortness of breath. before, during, and after the The perception of dyspnea will be assessed before, during, and recovery of the 6 MST, CPET, and 6 MWT.

Trial Locations

Locations (1)

Gazi University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Cardiopulmonary Rehabilitation Unit; Ankara, Çankaya, Turkey (Türkiye)