Evaluation of Long-Term Inflammatory Responses after Implantation of a Novel Fully Bioabsorbable Scaffold Composed of Poly-L-lactic Acid and Amorphous Calcium Phosphate Nanoparticles

Table 1

The peri-strut inflammation score is based on the degree of inflammation and extent of the circumference of the artery involved.

Degree/extent	<1/4	1/4–1/2	>1/2
1	1	1	2
2	1	2	3
3	2	3	3

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).