Case report of a peripheral artery disease patient with its aetiology clarified by retrograde angioscopy.

Background: Angioscopy plays an important role providing much information regarding vessel surfaces as macro-pathology in living patients. However, its viewing field is sometimes limited due to insufficient removal of blood flow and a catheter that cannot be controlled to view the intended direction. Angioscopy from a retrograde approach was found to overcome these limitations. Case summary: A 68-year-old man was admitted to our hospital with acute intermittent claudication for 2 weeks. He was diagnosed with acute limb ischaemia (ALI) in his left superficial femoral artery, and revascularization by endovascular treatment was attempted. A bi-directional approach was needed for successful revascularization with thrombus aspiration and angioplasty. Subsequent angioscopic examination from the retrograde approach visualized a clear and adequate image of the vessel and helped identify the aetiology of the case as on-site thrombosis at an atherosclerotic lesion. Discussion: It is important to understand the aetiology of ALI in each case for the management of the patient. Angioscopy can be a useful modality to identify the aetiology. It was found that retrograde angioscopy has several advantages over antegrade angioscopy in clear visualization and intentional control of the angioscopy catheter. This methodology may help us identify the aetiology of ALI by evaluating the vessel walls of patients with peripheral artery disease more precisely.