ABSTRACT
Critical limb ischemia (CLI) can be defined as chronic ischemic rest pain, ulcers, or gangrene due to objectively proven arterial occlusive disease. Data on the natural history of CLI comes from those patients who do not undergo intervention. However, because these patients have severe unreconstructable disease or failed primary intervention, this group is not truly representative of the natural history of the disease. Smoking has been widely accepted as the most important modifiable risk factor for development of CLI. The underlying disease process in CLI is progressive atherosclerosis. In the macrocirculation this causes severe narrowing or occlusion of the proximal arteries, thus reducing blood flow and perfusion pressure to the distal circulation. This condition is often complicated by thrombosis. Increased tissue pressure from venous insufficiency, emboli from other sites, and decreased cardiac output may all contribute to further reduction in the capillary perfusion.
