The natural history of untreated severe or critical limb ischemia

Objective: Critical limb ischemia (CLI) is associated with high morbidity and mortality. Because most patients with CLI will eventually undergo some type of revascularization, the natural history of CLI is not well defined, although it is important to know when patients decide to pursue treatment.

Methods: We systematically searched multiple databases for controlled and uncontrolled studies of patients with CLI who did not receive revascularization with a minimum follow-up of ≥1 year. Predefined outcomes of interest were mortality, major amputation, and wound healing. Random-effects meta-analysis was used to pool cumulative incidence across studies.

Results: We identified 13 studies enrolling 1527 patients. During a median follow-up of 12 months, all-cause mortality rate was 22% (confidence interval [CI], 12%-33%) and major amputation rate was 22% (CI, 2%-42%). Worsened wound or ulcer was found at 35% (CI, 10%-62%). There was a trend toward improvement in mortality and amputation rate in studies done after 1997. The quality of evidence was low because of increased risk of bias and inconsistency.

Conclusions: Mortality and major amputations are common in patients who have untreated CLI during a median follow-up of 1 year, although these outcomes have improved in recent times.