Semiquantitative analysis of histopathologic changes in vessels treated with the Trevo device
| Score | 0 | 1 | 2 | 3 | 4 |
| Endothelium | |||||
| Endothelial loss (%) | None | <25% of the circumference | 25–50 | 51–75 | >75 |
| Thrombus | |||||
| Thrombus (fibrin/platelet) | None | Minimal, focal | Mild, multifocal | Moderate, regionally diffuse | Severe, marked diffuse or total luminal occlusion |
| Hemorrhage | |||||
| Adventitial | None | Focal, occasional | Multifocal and regional | Regionally diffuse | 100% red blood cells |
| Medial | None | Focal, occasional | Multifocal and regional | Regionally diffuse | 100% red blood cells |
| Medial injury | |||||
| Medial injury (device induced) | None | Focal disruption of the IEL | Widespread disruption of the IEL | Medial tear not extending beyond the EEL | Medial tear with involvement of the EEL |
EEL, external elastic lamina; IEL, internal elastic lamina.