The natural history of peripheral vascular disease. Implications for its management. The durability and the eventual complication rate of endovascular therapy (percutaneous transluminal angioplasty, laser-assisted angioplasty, and atherectomy) are not yet entirely clear, especially with respect to the treatment of atherosclerotic lesions in the femoropopliteal or distal arterial segments. Therefore, the indications for its use have not been firmly established and must take into consideration the natural history of the occlusive disease itself. Although some type of procedural intervention clearly is warranted in the presence of ischemic rest pain or tissue necrosis, intermittent claudication is the only complaint in approximately 70% of patients who present with either aortoiliac or femoropopliteal involvement. Most nondiabetic patients experience substantial symptomatic improvement with a daily exercise program, and their long-term risks for either abrupt deterioration (20-25%) or amputation (less than 10%) are relatively low. In comparison, the 5-year mortality rate ranges from 20-40% even in claudicants, and as many as 40% of those with clinical indications of associated coronary artery disease have been shown angiographically to be candidates for myocardial revascularization. These observations suggest that traditional indications for surgical treatment (truly disabling claudication and/or limb salvage) also should be applied to endovascular therapy until its success is confirmed beyond speculation, and that incidental coronary disease deserves particular attention in patients with lower extremity ischemia. 