Mitochondrial Function in Peripheral Arterial Disease (MIVA)

Effect of Different Treatment Strategies on Mitochondrial Function in Peripheral Arterial Disease - a Randomized Controlled Trial

The aim of this study is to investigate the effect of different treatment strategies on mitochondrial function and to correlate in-vitro results to findings from in-vivo measurements of mitochondrial function. The authors hypothesize that interventional revascularization and therefore the restoration of blood and oxygen supply is more relevant to mitochondrial function compared to the effect of exercise training.

Resulting from a chronic narrowing of arteries by atherosclerotic lesions, the leading clinical symptom of peripheral arterial disease (PAD), a walking induced pain, reduces quality of life of patients. Affected muscle regions are altered by a characterized myopathy and mitochondria are known to play a crucial role in this pathophysiological mechanism. There are different methodological approaches to investigate mitochondrial function in-vivo as well as in-vitro. Regarding our own preliminary data, mitochondria are known to recover after successful revascularization. The effect of different treatment strategies on mitochondrial function and the correlation of in-vitro to clinical more applicable in-vivo methods was understudied so far. The overall aim of this study is to investigate the effect of different treatment strategies on mitochondrial function and to correlate in-vitro results to findings from in-vivo measurements of mitochondrial function. The authors hypothesize that interventional revascularization and therefore the restoration of blood and oxygen supply is more relevant to mitochondrial function compared to the effect of exercise training. Patients with isolated pathologies of the superficial femoral artery and symptomatic PAD (Fontaine stage IIB) will be included and randomized to different treatment groups (conservative treatment versus interventional revascularization). Near-infrared refracted spectroscopy and the TIVITA ® hyperspectral camera will be used for in-vivo measurement of peripheral oxygen saturation and distal perfusion before and after an exercise. Muscle biopsies will be obtained from affected (gastrocnemius muscle) as well as from unaffected muscle (lateral vastus muscle) shortly before and 12 weeks after initiating treatment. Muscle samples will be investigated by measurement of CSA regarding mitochondrial content and HRR regarding mitochondrial respiration as well as for oxidative stress.

mitochondrial function, respirometry, near infrared spectroscopy, endothelial dysfunction, peripheral arterial disease, exercise training, revascularisation

Prospective randomized controlled trial Exercise group Revascularization group Healthy control group

Patients with intermittent claudication will receive conservative treatment with monitored exercise training for a total of 12 weeks (home-based training, minimum of three times a week, documented by using a diary with documentation of the type, the intensity and the duration of the training as well as by using a physical activity monitoring system (Move 4, Karlsruhe, Germany).

will receive revascularization of the underlying atherosclerosis lesion of the superficial femoral artery. Depending on the exact morphology of the lesion, patients with short superficial femoral artery lesions (<25 cm) will be subdivided into group 2A with endovascular treatment and patients with long superficial femoral artery lesions (>25 cm) will be subdivided into group 2B with open surgical treatment

Patients undergoing surgery for symptomatic varicose veins with excluded PAD will serve as a control group.

Depending on the exact morphology of the lesion, patients with short superficial femoral artery lesions (<25 cm) will be subdivided into group 2A with endovascular treatment (percutaneous transluminal angioplasty with or without stenting) and patients with long superficial femoral artery lesions (>25 cm) will be subdivided into group 2B with open surgical treatment (femoropopliteal bypass) .

Home-based monitored exercise training (walking), 3 times a week, monitored with log book and activity sensors.

Evaluation of endothelial dysfunction with ultrasound measurements of flow mediated dilation of the brachial artery.

Evaluation of cardiovascular risk with measurement of maximal walking distance (meters) in 6 minutes.

Inclusion Criteria: Isolated flow limiting arteriosclerotic lesion of the superficial femoral artery Unilateral grade II b (Fontaine) peripheral arterial disease Informed consent Exclusion Criteria: Flow limiting arteriosclerotic lesions of the infrarenal aorta, iliac arteries or common/ deep femoral artery Contraindication for exercise therapy