Table 1.

Human coronary morphological plaque vulnerability index (MPVI) definition and AHA classifications

MPVI	Plaque	Description	AHA classification
V = 0	Very stable	Normal or slight intimal thickening	Type I, some atherogenic lipoprotein and intimal thickening
V = 1	Stable	Moderate intimal thickening, no extracellular lipid, calcification or significant inflammation	Type II (fatty streak), III (preatheroma)
V = 2	Slightly unstable	Small lipid core (<30% of plaque size); calcification may be present; thick fibrous cap (> 150 μm); little or no inflammation at plaque shoulders	Type IV, Vb, and Vc with less than 30% NC by area; or VII/VIII
V = 3	Moderately unstable	Moderate lipid core (30 – 40% of plaque size) and fibrous cap (65 – 150 μm); moderate intraplaque hemorrhage; moderate inflammation.	Type Va, IV/V with 30-40% NC by area
V = 4	Highly unstable	Large lipid core(>40%); thin fibrous cap (< 65 μm); large intraplaque hemorrhage; extensive inflammation; evidence of previous plaque rupture	Type VI; IV/V with > 40% NC by area

Cap thickness threshold values were modified from previously published values to adjust to the differences between coronary and carotid plaques based on available literature.