Angiographic Appearance of Coronary Artery Ectasia
Coronary artery ectasia appears on angiography as a diffuse dilatation of the coronary artery with a diameter at least 1.5 times wider than the adjacent normal coronary artery segment, typically extending over 20 mm in length or greater than one-third of the vessel. 1
Diagnostic Criteria and Characteristics
Coronary artery ectasia can be identified on coronary angiography using the following criteria:
- Diameter measurement: The internal lumen diameter is at least 1.5 times larger than an adjacent normal segment 1
- Length assessment: The dilated segment typically extends over 20 mm or greater than one-third of the vessel 2
- Appearance pattern: May be diffuse (involving the entire vessel) or segmental (involving only a portion) 1
- Morphology: Shows lack of normal tapering and may demonstrate perivascular echogenicity or "brightness" 1
Differentiation from Aneurysms
While ectasia and aneurysms are sometimes used interchangeably, they have distinct characteristics on angiography:
- Ectasia: Diffuse dilatation with gradual tapering
- Aneurysm: Focal dilatation that can be:
- Saccular: When axial and lateral diameters are nearly equal
- Fusiform: When there is symmetric dilatation with gradual proximal and distal tapering 1
Distribution Patterns
Coronary ectasia can be classified based on distribution:
- Type I: Diffuse ectasia in multiple vessels
- Type II: Diffuse ectasia in one vessel and localized in another
- Type III: Diffuse ectasia in one vessel only
- Type IV: Localized or segmental ectasia
Angiographic Challenges and Considerations
When evaluating coronary ectasia on angiography, several important factors should be considered:
- Normal variation: Care must be taken in making the diagnosis due to considerable normal variation in coronary artery distribution and dominance 1
- Measurement technique: Measurements should be made from inner edge to inner edge and should exclude points of branching, which may have normal focal dilation 1
- Associated findings: Look for intraluminal thrombi, which may be present in ectatic segments 1
- Flow characteristics: Ectatic vessels often demonstrate slow flow, which can be visualized on angiography 3
- Luminal irregularity: The coronary lumen may appear clearly irregular in ectatic segments 1
Common Locations
In order of highest to lowest frequency, common sites of coronary ectasia include:
- Proximal left anterior descending (LAD) artery
- Proximal right coronary artery (RCA)
- Left main coronary artery (LMCA)
- Left circumflex (LCX)
- Distal RCA 1
Potential Pitfalls in Diagnosis
- Misinterpreting normal variations in vessel caliber as ectasia
- Failing to distinguish between focal aneurysms and diffuse ectasia
- Not recognizing associated atherosclerotic disease, which commonly coexists with ectasia
- Overlooking thrombus formation within the ectatic segment, which may appear as filling defects 1, 3
Coronary artery ectasia requires careful evaluation and measurement on angiography, with attention to vessel diameter, length of involvement, and associated findings to ensure accurate diagnosis and appropriate management.