Safety and Effectiveness of Bone Marrow Cell Concentrate in the Treatment of Chronic Critical Limb Ischemia Utilizing a Rapid Point-of-Care System

Table 3

Definition of the classification system used to quantify the collateral vessel number and size.

Category	Number of
Category 0	0 collateral vessels
Category 1	1–3 collateral vessels
Category 2	4–7 collateral vessels
Category 3	≥8 collateral vessels
Collateral vessel grade	Size of collateral vessels
Grade 0	0 collateral vessels
Grade 1	≤5 small
Grade 2	5
Grade 3	≤5 large ± small
Grade 4	5 large ± small

collaterals occupy <25% of the length of the imaged thigh and <50% of the diameter of the superficial femoral artery. Large collaterals occupy 25% of the length of the imaged thigh and ≥50% of the diameter of the superficial femoral artery.