Outgrowth of cells from adventitial explants analyzed according to three levels of limb ischemia, per the WIfI definitions (WIfI grades 0 + 1, AAI ≥ 0.6, N=13; WIfI 2, AAI 0.59-0.4, N=12; and WIfI 3, AAI less than 0.4, N=21). The outgrowth by WIfI grades 0+1 were significantly different from both lower grades, 2 and 3 (P < 0.001, 2-way ANOVA over all the days measured).