The Effects of Metformin on Functional Capacity in Individuals With Peripheral Artery Disease-Related Intermittent Claudication

This is an interventional treatment trial for Peripheral Arterial Disease focused on measuring Peripheral Arterial Disease, Intermittent Claudication, Peripheral Vascular Diseases, Vascular Diseases, Cardiovascular Diseases, Arterial Occlusive Diseases, Atherosclerosis, Insulin Resistance, Glucose Metabolism, Blood Glucose, Metformin, Biguanides, Hypoglycemic Agents, Endothelium, Vascular, Hemorheology, Blood Circulation, Regional Blood Flow, Microcirculation, Exercise, Physical Fitness, Exercise Test, Sedentary Lifestyle, Quality of Life, Plethysmography Read More

Inclusion Criteria:

• Age ≥40 years old.
• Resting ankle-brachial index (ABI) ≤0.90 in the limiting leg(s), or a >20% reduction in the ABI measured immediately post-exercise where the resting ABI is >0.90. In cases of incompressible arteries in the limiting leg(s) (i.e. ABI ≥1.40), a toe-brachial index (TBI) of ≤0.70 is required.
• Peripheral artery stenosis/occlusion in the limiting leg(s), documented by duplex ultrasonography or other imaging tests.
• Stable (i.e. 3-month history) intermittent claudication in at least one PAD-affected leg.
• Maximum walking time during graded treadmill exercise testing (Gardner-Skinner protocol) ≥1 minute and ≤16 minutes.
• Concurrent medications that may affect primary, secondary or exploratory endpoints have remained stable over the previous 3 months.
• Have given signed informed consent to participate in the study.

Exclusion Criteria:

• Identification of any other medical condition requiring immediate therapeutic intervention.
• Clinically significant abnormal electrocardiogram (ECG) at rest or during exercise that represents a contraindication to study procedures or the study drug.
• Myocardial infarction, unstable angina, percutaneous transluminal coronary angioplasty (PTCA), coronary artery bypass graft surgery (CABG), or other major surgery within the previous 6 months.
• Exercise capacity limited by a factor other than PAD-related intermittent claudication.
• Any condition that precludes valid completion of a treadmill exercise test.
• Critical limb ischemia in either leg, defined as PAD-related chronic ischemic rest pain or skin lesions (ulcers, gangrene).
• Previous peripheral revascularisation or other surgical treatment for PAD in the previous 6 months.
• Known non-atherosclerotic cause of PAD.
• Active cancer.
• Uncontrolled hypertension (resting brachial blood pressure ≥160/100 mmHg).
• Evidence of pharmacologically-treated or poorly controlled (i.e. HbA1c ≥7.5%) type 2 diabetes or other class of diabetes (e.g. type 1 diabetes).
• Known intolerance or contraindication(s) to metformin.
• Known contraindication(s) to "Definity" (perflutren lipid microsphere).
• Participation or intention to participate in another clinical research study during the study period.
• History of non-compliance to medical regimens or unwillingness to comply with the study protocol.
• Any other condition that in the opinion of the Investigators would confound the evaluation and interpretation of the data.
• Persons directly involved in the execution of the protocol.
• Incapable of providing written informed consent due to cognitive, language, or other reasons.