Clinical trial NCT01970332: Mechanisms That Produce the Leg Dysfunction of Claudication & Treatment Strategies
Official title: Mitochondrial Dysfunction, Oxidative Damage and Inflammation in Claudication
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Peripheral Arterial Disease
Keywords: Peripheral Arterial Disease
Peripheral Vascular Disease
Claudication
Myopathy
Oxidative stress
Mitochondrial dysfunction
Biomechanics
Inflammation
Lead sponsor: University of Nebraska
Sponsor class: OTHER
Collaborators: name: National Institute on Aging (NIA)
name: American Heart Association
First posted: 2013-10-28
Enrollment: 220
Sex: ALL
Standard ages: CHILD
ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Allocation: NON_RANDOMIZED
Intervention model: SINGLE_GROUP
Primary purpose: HEALTH_SERVICES_RESEARCH

Brief 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.

Detailed 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.

Eligibility criteria: 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

Primary outcomes:
measure: Walking distances
timeFrame: six months
measure: Quality of life Questionnaires
timeFrame: six months
measure: Leg biomechanics
timeFrame: six months
measure: Leg hemodynamics
timeFrame: 6 months
Secondary outcomes:
measure: Myofiber Mitochondrial Function
timeFrame: 6 months
measure: Myofiber Oxidative Damage
timeFrame: 6 months
measure: Muscle inflammation
timeFrame: 6 months
measure: Myofiber Morphology
timeFrame: 6 months
Other outcomes:
Locations:
city: Omaha
country: United States
facility: Veterans Affairs Medical Center, Omaha
state: Nebraska
Study officials:
affiliation: University of Nebraska
name: Iraklis I Pipinos, MD, PhD
role: PRINCIPAL_INVESTIGATOR
References: