This document describes the classification of lesions in coronary arteries according to the ACC/AHA system. Type A lesions are discrete and less than 10 mm in length, with a concentric shape, smooth contour, and little or no calcification. Type B1 lesions are tubular, between 10-20 mm in length, eccentric in shape, with moderate tortuosity and angulation between 45-90 degrees and irregular contour with moderate to heavy calcification. Type B2 lesions have two or more characteristics of B1 lesions. Type C lesions are diffuse, over 2 cm in length, with total occlusion over 3 months old and excessive tortuosity or angulation over 90 degrees.

1. Atheromatous coronary
artery disease
Lesion-specific classification of the primary target stenosis :ACC/AHA

2. types subtype Lesion characteristic according to AHA/ACC classification
A
0
Discrete (< 10
mm length)
Concentric Readily
accessible
Non angulated
segment < 45°
Smooth
contour
Little or no
calcification
Discrete (<
10 mm
length)
Concentric
Less than totally occlusive ,Not ostial in location,No major branch involvement,Absence of thrombus
B B1
Tubular (10-20
mm length)
Eccentric Moderate
tortuosity of
proximal
segment
Moderately
angulated
segment, 45°-
90°
Irregular
contour
Moderate to
heavy
calcification
Tubular
(10-20 mm
length)
Eccentric
Total occlusion < 3-mo-old,Ostial in location,Bifurcation lesions requiring double Guidewires,Some thrombus present
B2 Two or more “B” characteristics
C 0 Diffuse (> 2 cm
length)
Total occlusion
> 3-mo-old
Excessive
tortuosity of
proximal
segment
Extremely
angulated
segments, > 90°
Inability to
protect
major side
branches
Degenerated
vein grafts with
friable lesions
Diffuse (> 2
cm length)
Total occlusion
> 3-mo-old