Coronary angiography ACC-AHA characteristics of type A, B, and C coronary lesions

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Coronary Angiography


General Principles

Historical Perspective
Appropriate Use Criteria for Revascularization
Film Quality

Anatomy & Projection Angles

Normal Anatomy

Coronary arteries
Right System
Left System
Left Main
Left Anterior Descending
Median Ramus

Anatomic Variants

Separate Ostia
Anomalous Origins
Case Example

Projection Angles

Standard Views
Left Coronary Artery
Right Coronary Artery

Epicardial Flow & Myocardial Perfusion

Epicardial Flow

TIMI Frame Count
TIMI Flow Grade
TIMI Grade 0 Flow
TIMI Grade 1 Flow
TIMI Grade 2 Flow
TIMI Grade 3 Flow
TIMI Grade 4 Flow
Pulsatile Flow

Myocardial Perfusion

TIMI Myocardial Perfusion Grade
TMP Grade 0
TMP Grade 0.5
TMP Grade 1
TMP Grade 2
TMP Grade 3

Lesion Complexity

ACC/AHA Lesion-Specific Classification of the Primary Target Stenosis

Preprocedural Lesion Morphology

Intimal Flap
Sawtooth Pattern
Ostial location
Proximal tortuosity
Degenerated SVG
Total occlusion
Coronary Artery Thrombus
TIMI Thrombus Grade
TIMI Thrombus Grade 0
TIMI Thrombus Grade 1
TIMI Thrombus Grade 2
TIMI Thrombus Grade 3
TIMI Thrombus Grade 4
TIMI Thrombus Grade 5
TIMI Thrombus Grade 6

Lesion Morphology

Quantitative Coronary Angiography
Definitions of Preprocedural Lesion Morphology
Irregular Lesion
Disease Extent
Arterial Foreshortening
Infarct Related Artery
Degenerated SVG

Left ventriculography

Quantification of LV Function
Quantification of Mitral Regurgitation

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Rim Halaby, M.D. [2]; Vanessa Cherniauskas, M.D. [3]


The American College of Cardiology/American Heart Association (ACC/AHA) Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures developed a classification scheme to characterize the complexity of coronary stenosis and the probability of success of a percutaneous intervention. ACC/AHA lesion complexity system provides short-term prognostic information adjunctive to TIMI flow grade (TFG) and TIMI myocardial perfusion grade (TMPG).

ACC/AHA Lesion-Specific Classification of the Primary Target Stenosis

The lesion-specific classification was proposed by the Subcommittee on Percutaneous Transluminal Coronary Angioplasty to estimate the likelihood of a successful angioplastic procedure (defined as one in which a ≥20% change in luminal diameter is achieved, with the final diameter stenosis <50% and without the occurrence of death, acute myocardial infarction, or the need for emergency bypass operation) as well as the likelihood of developing abrupt vessel closure.[1]

Type A Lesions (High Success, >85%; Low Risk)

Type A lesions are associated with an anticipated success procedure rate of ≥85% and a low risk of abrupt closure. Type A lesions demonstrate all of the following characterisitics:

  • Discreteness (<10 mm in length)
  • Concentricity
  • Ready accessibility
  • Location in a nonangulated segment (<45°)
  • Smoothness of contour
  • Little or no calcification
  • Absence of total occlusion
  • Nonostial location
  • Absence of major branch involvement
  • Absence of thrombus

Type B Lesions (Moderate Success, 60 to 85%; Moderate Risk*)

Type B lesions are associated with an anticipated success procedure rate ranging from 60 to 85% or a moderate risk of abrupt closure, or both. Type B lesions include all lesions that are neither type A nor type C and are usually identified by, but not limited to, the following characterisitics:

  • Tubular shape (10 to 20 mm in length)
  • Eccentricity
  • Accessibility influenced by moderate tortuosity of proximal segment
  • Location in a moderately angulated segment (>45°, <90°)
  • Irregularity of contour
  • Moderate or severe calcification
  • Presence of thrombus
  • Ostial location
  • Bifurcation lesions requiring double guide wires
  • Total occlusions <3 months old

* Although the risk of abrupt vessel closure is moderate, in certain circumstances the likelihood of a major complication may be low as in dilation of total occlusions <3 months old or when abundant collateral channels supply the distal vessel.

Type C Lesions (Low Success, <60%; High Risk)

Type C lesions are associated with an anticipated success procedure rate of <60% or a high risk of abrupt closure, or both. Type C lesions demonstrate any of the following characterisitics:

  • Diffuseness (>20 mm in length)
  • Excessive tortuosity of proximal segments
  • Location in an extremely angulated segment (>90°)
  • Total occlusion >3 months old
  • Inability to protect major side branches
  • Degeneration of older vein grafts with friable lesions

Modified ACC/AHA Lesion-Specific Classification of the Primary Target Stenosis

The standard ACC/AHA classification of the primary target stenosis is prospectively modified to subdivide type B stenoses into B1 (one adverse characteristic) and B2 (≥ two adverse characteristics) on the basis of previous studies suggesting the cumulative significance of mutiple adverse lesion characteristics.[2]

Clinical Significance


  1. Ryan TJ, Faxon DP, Gunnar RM, Kennedy JW, King SB III, Loop FD,Peterson KL, Reeves TJ, Williams DO, Winters WL Jr, et al. Guidelines for percutaneous transluminal coronary angioplasty. A report of the American College of Cardiology/American Heart Association Task Force on Assessment of Diagnostic and Therapeutic Cardiovascular Procedures (Subcommittee on Percutaneous Transluminal Coronary Angioplasty). Circulation 1988;78:486–502.
  2. Ellis, SG.; Vandormael, MG.; Cowley, MJ.; DiSciascio, G.; Deligonul, U.; Topol, EJ.; Bulle, TM. (1990). "Coronary morphologic and clinical determinants of procedural outcome with angioplasty for multivessel coronary disease. Implications for patient selection. Multivessel Angioplasty Prognosis Study Group". Circulation. 82 (4): 1193–202. PMID 2401060. Unknown parameter |month= ignored (help)
  3. 3.0 3.1 Gibson CM, Bigelow B, James D, Tepper MR, Murphy SA, Kirtane AJ; et al. (2004). "Association of lesion complexity following fibrinolytic administration with mortality in ST-elevation myocardial infarction". Am J Cardiol. 94 (1): 108–11. doi:10.1016/j.amjcard.2004.03.038. PMID 15219518.