Degree score: 0 = not present; 1 = scattered inflammatory cells; 2 = small and segmental aggregates of inflammatory cells; 3 = larger aggregates widespread or circumferentially distributed. The extent (<1/4, 1/4–1/2, and >1/2) refers to the portion of the circumference of the artery involved. In general, inflammation scores of 0 and 1 denote excellent local biocompatibility, namely, if neutrophils are not seen. An inflammation score of 2 or 3 may denote a biocompatibility issue, especially if neutrophils or large numbers of lymphocytes are present. Large proportions of eosinophils and lymphocytes may be indicative of a hypersensitivity response (Otsuka, 2015).