PECAM1 and ulcer disease: Ulceration (n = 40) and hemorrhage-positive plaques (n = 30) had slightly, but not significantly, higher values of CD31+ surface area than their negative counterparts (0.72 ± 0.16% vs. 0.61 ± 0.11%, p = 0.607 and 0.69 ± 0.20% vs. 0.66 ± 0.11%, p = 0.324).