Morphologic Changes of the Femoropopliteal Arterial Segment with Knee Flexion after Endovascular Therapy

Objective: The purpose of this study is to investigate morphologic changes of the femoropopliteal arterial segment (FPAS) with knee flexion after endovascular therapy (EVT). Methods: From July 2012 to January 2015, EVT was performed on 12 limbs in 12 consecutive patients who had obliterative lesions in the FPAS. After the implantation of nitinol stents, angiography was performed with the knee in both extension and flexion to investigate morphologic changes of the FPAS. Results: On angiography, the distal end of the implanted stent was placed at various distances (5-10 cm in two cases, 10-15 cm in nine cases, and 15-20 cm in one case) above the knee joint line with the knee in extension. In all cases, although the popliteal artery was highly bent with the knee in flexion, the FPAS morphology was highly variable. However, the most proximal bending point of the FPAS was about 10 cm above the knee joint line. In one case, the artery was occluded at the distal part of the stent 16 months later, probably due to EVT. Conclusion: In EVT of the FPAS, it is important to consider the characteristics and position of the stent to prevent complications.