The course of PAD is notable for progressive atherothrombosis involving one or multiple arterial vascular beds (coronary, cerebrovascular, or lower extremity arteries). Thus, PAD patients have a heightened risk of ischemic cardiovascular, cerebrovascular, and limb events. The incidence of cardiovascular events is considerably higher than the morbidity and death from limb complications. The summary of clinical course of patients with PAD is shown in Figure 1 (6).
At 5 years following the diagnosis of PAD, 70-80% have stable claudication, 10-20% have worsening claudication and only a fraction require revascularization.
Critical limb ischemia (CLI), a severe manifestation of PAD, may be present at initial diagnosis of PAD in 1-2% of patients with PAD (7). CLI is associated with significant mortality and morbidity. As such, one year after the diagnosis of CLI, one in four patients may require amputation or die from cardiovascular causes (6). Besides, among patients who were asymptomatic, or had atypical symptoms or claudication at initial diagnosis of PAD, 1-2% may progress to CLI at 5 years (6). A recent analysis of the Medicare claims data reported 54% mortality and 3% major amputation at 4 years following the initial diagnosis of CLI (8).
Twenty percent of patients with PAD will have a myocardial infarction or stroke within 5 years after the diagnosis of PAD. PAD is associated with an increased risk of death, mostly from cardiovascular causes; as such, the risk of death at 5 years is 15-30%, of which 75% are cardiovascular in origin (6, 9).