Coronary angiography ACC-AHA characteristics of type A, B, and C coronary lesions
Anatomy & Projection Angles
Epicardial Flow & Myocardial Perfusion
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.
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)
- 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)
- 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.
- A greater ACC/AHA lesion complexity at 60 to 90 minutes after fibrinolytic administration was shown to be associated with poorer epicardial flow and myocardial perfusion as well as a higher risk of pulmonary edema, shock, and mortality within 30 days. However, increased lesion complexity was not associated with a higher risk of recurrent myocardial infarction.
- Independent of left anterior descending coronary artery infarct location, TIMI grade 3 flow, age, performance of rescue or adjunctive PCI, pulse, and systolic blood pressure on admission, type C lesion complexity was associated with an increased short-term mortality rate at 30 days.
- 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.
- 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
- 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.