Antithrombotic Therapy After Peripheral Angioplasty

Peripheral arterial disease affects approximately 12% of adults and 20% of adults over 70 years (Hiatt et al., 1995). This disease results from one or more lesions in the arterial system of the lower extremity that restrict blood flow. The restriction of blood flow during ambulation may cause intermittent claudication, i.e. muscular pain due to lack of blood supply. About one fifth of people with peripheral arterial disease have intermittent claudication. About half of people with peripheral arterial disease are asymptomatic. A small part of people with peripheral arterial disease (< 10%) have critical limb ischemia, i.e. rest muscular pain and/or ischemic ulceration or gangrene of toes. Based on the severity of symptoms, the stages of the disease are classified as Fontaine stages I-IV, where stage I is asymptomatic, stage IIa is the occurrence of intermittent claudication after a pain-free walking distance of more than 200 m, stage IIb is intermittent claudication after less than 200 m, stage III is rest pain, and stage IV is the presence of ischemic ulcers. Patients with peripheral arterial disease, which is an expression of systemic atherosclerosis, have an increased risk of cardiovascular events (Hankey et al., 2006). Medical therapy should include modification or elimination of atherosclerotic risk factors (cigarette smoking, diabetes mellitus, hypertension, hyperlipidemia), and antiplatelet therapies to decrease the risk of cardiovascular events and to improve survival. Moreover, the initial approach to the treatment of limb symptoms should focus to relieve discomfort, to improve exercise performance, and daily functional abilities by means of structured exercise and, in selected patients, pharmacotherapies to treat the exercise limitation of claudication (Norgren et al, 2007). Lower extremity revascularization is indicated for patients with a lifestyle-limiting disability due to intermittens claudication or with chronic critical limb ischemia (Hirsch et al., 2006; Norgren et al., 2007). There are two types of revascularization procedure: endovascular or surgical. Percutaneous transluminal angioplasty with or without stenting is an endovascular technique for revascularizing obstructed arteries. It was first introduced by Dotter and Judkins (Dotter & Judkins, 1964), and subsequently improved by Grüntzig (Grüntzig & Hopff, 1974). In peripheral transluminal angioplasty the recanalization of obstructed arteries is obtained by dilatation of a stenosis (i.e. a narrowing of the vessel diameter) or recanalization of a total occlusion, using a wire-guided inflatable balloon catheter. Usually the femoral artery in the