SURVEILLANCE PROTOCOL. Examinations were performed at baseline and at 24 hours, 3 months, 6 months and 12 months after randomization, including staging of PAD by Rutherford1, measurement of resting ABI, treadmill exercise testing (3.2 km/h at 12° slope), and color duplex ultrasonography16. At 6 and 12 months X-rays in two planes were obtained for evaluation of stent fractures.