Mechanisms That Produce the Leg Dysfunction of Claudication & Treatment Strategies

Peripheral Arterial Disease Clinical Trial

Official title:

Mitochondrial Dysfunction, Oxidative Damage and Inflammation in Claudication

Clinical Trial Details — Status: Completed

Administrative data

• NCT number: NCT01970332
• Other study ID #: 0510-10-ET
• Secondary ID: 5R01AG03499515PO
• Status: Completed
• Phase: N/A
• Start date: September 1, 2010
• Est. completion date: May 30, 2016

Study information

• Verified date: September 2023
• Source: University of Nebraska
• Contact: n/a
• Is FDA regulated: No
• Study type: Interventional

Clinical Trial Summary

Intermittent claudication afflicts 5% of the US population older than 55 years of age and develops along with hardening of the arteries of the legs. Claudicating patients limp and can only walk very short distances because their legs hurt. This protocol evaluates the mechanisms that may produce the leg dysfunction of claudication and its successful completion can ultimately produce significant new diagnostic and treatment strategies for the care of claudicating patients.

Description:

Claudication, defined as walking-induced leg discomfort and gait dysfunction relieved by rest, affects 5% of Americans over 55 years of age. Claudicating patients adopt sedentary lifestyles and cluster at the extreme low end of the physical activity spectrum, escalating risk for adverse health effects. The primary therapeutic goals for claudicating patients are restoration of leg function and prevention of disease progression. Current, rehabilitative interventions focus on inadequate blood flow as the only cause of claudication. Operative revascularization and/or exercise therapy are the principal conventional therapeutic modalities, providing only modest rehabilitative benefit. Applying biomechanical analysis to gait of claudicating patients, the investigators team has developed preliminary data indicating that blood flow is not the only mechanism producing the limb dysfunction of claudication. Several laboratories including the investigators own have demonstrated a myopathy, characterized by mitochondrial dysfunction, oxidative damage and inflammation, in leg skeletal muscle of claudicating patients. These conditions have not been quantified, comprehensively, in relation to claudication, and their association with severity of claudication is not known. The investigators hypothesis is that blood flow restriction is not a good predictor of limb dysfunction in claudication, whereas muscle mitochondrial dysfunction, oxidative damage and inflammation are strong predictors of limb dysfunction both at baseline and after conventional therapy with revascularization or supervised exercise. Under Aim #1, the investigators will acquire precise measurements of gastrocnemius mitochondrial function, oxidative damage and inflammation in claudicating patients, at the time of their initial presentation, and evaluate these measurements as predictors of objective measures of limb function and subjective measures of quality of life. Under Aims #2 and #3, the investigators will evaluate the effects of revascularization (Aim#2) and supervised exercise therapy (Aim#3) on mitochondrial dysfunction, oxidative damage and inflammation in claudicating gastrocnemius and on objective measures of limb function and subjective measures of quality of life. If the investigators hypothesis is correct, the work in Aim #2 will for the first time definitively demonstrate that blood flow restriction due to blockages in the arterial tree is not the only cause of claudication. The work under Aims #2 and #3 will determine whether revascularization or exercise therapy has a beneficial effect on the myopathy of claudicating muscle with associated improvement in limb function and quality of life. Finally, the proposed studies under Aims #1, #2 and #3 will provide quantitative modeling of a panel of mechanistic (bioenergetics, oxidative stress and inflammation) parameters as predictors of objective measurements of claudicating limb function and subjective measures of quality of life commonly used for clinical assessment. Measurements of gastrocnemius mitochondrial function, oxidative damage and inflammation may be useful tools that permit staging of disease for optimum intervention and evaluation of therapeutic interventions that specifically target these conditions, improving rehabilitative outcomes.

Recruitment information / eligibility

• Status: Completed
• Enrollment: 220
• Est. completion date: May 30, 2016
• Est. primary completion date: May 30, 2016
• Accepts healthy volunteers: No
• Gender: All
• Age group: N/A and older

Eligibility

Inclusion Criteria:

• a positive history of chronic claudication
• exercise-limiting claudication established by history and direct observation during a screening walking test administered by the evaluating vascular surgeon
• an ankle/brachial index < 0.90 at rest

Exclusion Criteria:

• absence of Peripheral Arterial Disease (PAD)
• acute lower extremity ischemic event secondary to thromboembolic disease or acute trauma
• exercise capacity limited by conditions other than claudication including leg (joint/musculoskeletal, neurologic) and systemic (heart, lung disease) pathology

Related Conditions & MeSH terms

• Intermittent Claudication
• Peripheral Arterial Disease
• Peripheral Vascular Diseases

Intervention

Procedure:
• Revascularization Surgery

Other:
• Supervised exercise therapy

Locations

Country	Name	City	State
United States	Veterans Affairs Medical Center, Omaha	Omaha	Nebraska

Sponsors (3)

Lead Sponsor	Collaborator
University of Nebraska	American Heart Association, National Institute on Aging (NIA)

Country where clinical trial is conducted

United States, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Walking distances	Initial Claudication Distance, Absolute Claudication Distance, 6-Minute Walking Distance	six months
Primary	Quality of life Questionnaires	Walking Impairment Questionnaire and the Medical Outcomes Study Short Form 36 Healthy Survey	six months
Primary	Leg biomechanics	Propulsion Impulse, Ankle plantarflexor torque, Ankle plantarflexor power and maximum isometric plantarflexion force	six months
Primary	Leg hemodynamics	Ankle Brachial Index	6 months
Secondary	Myofiber Mitochondrial Function	Mitochondrial Respiration measured via polarography	6 months
Secondary	Myofiber Oxidative Damage	Myofiber content of HNE adducts and protein carbonyls. Muscle Manganese Superoxide Dismutase activity	6 months
Secondary	Muscle inflammation	Expression of pro- and anti-inflammatory cytokines and monocyte/macrophage cell counts.	6 months
Secondary	Myofiber Morphology	Cross-sectional area of the myofibers	6 months