Magnetic resonance imaging-based monitoring of collateral artery development in patients with intermittent claudication during supervised exercise therapy

Objective: The purpose of the current study was to determine whether supervised exercise therapy (SET) leads to measurable vascular adaptations in patients with intermittent claudication using contrast-enhanced magnetic resonance angiography and flow measurements. Methods: Ten patients with clinical symptoms of intermittent claudication and proven obstructive arterial lesions of the superficial femoral artery were included and underwent SET for a period of 6 months. At baseline, all patients underwent a treadmill test to assess pain free walking distance, ankle brachial index measurement, and magnetic resonance imaging to determine the number of arteries in the upper leg using contrast-enhanced magnetic resonance angiography and arterial peak flow in the popliteal artery using cine phase contrast angiography. All examinations were repeated after 3 and 6 months of SET, respectively, to evaluate vascular responses relative to baseline. Results: After 6 months of SET, mean pain free walking distance (395 +/- 46 m) was improved by 71% compared with baseline (230 +/- 42 m; P <.01). No statistically significant changes were found for mean values of ankle brachial index (81 +/- 4 and 77 +/- 4, respectively, at baseline and after 6 months of SET), number of arteries at the level of the arterial lesion (18 +/- 2 and 19 +/- 2, respectively) nor arterial peak flow (5.3 +/- 0.6 and 5.3 +/- 0.8 mL/s, respectively). Conclusions: SET in patients with intermittent claudication results in an increase in pain free walking distance, whereas with magnetic resonance imaging no macrovascular adaptations in terms of additional collateral artery formation or flow increases could be observed.