Coronary artery dilatation is a less discussed entity in clinical cardiology .It is important to realise coronary artery has one more behavioral pattern in response to atherosclerosis . Atherosclerosis not necessarily means obstructive disease . Dilatation is also a common expression of coronary atherosclerosis .
It all depends upon the medial weakness and resistance.If the medial weakness is more plaque grows inwards , if the resistance is more plaque grows out.(Read the related topic -Glagovian phenomenon )
What is the difference between aneurysm and ectasia?
The difference between ectasia, aneurysm are often subtle and mainly semantic. . If the length of the dilated segment is more than 50 % of diameter it is called ectasia. When the diameter is more than 50 % of length it is termed aneurysm .( With a minimal enlargement of 150 % of the reference segment. To add to the complexity both can occur in the same vessel.
Here is the patient from our institute who has an Aneurysm in LAD and ectasia in RCA.
- Ectasia generally do not limit blood flow.
- Thrombus formation in the walls can be common.
*Obstructive Ectasia.This can happen either when ectasia develops in an obstructive lesion or a ectatic lesion getting obstructed .
Stenting and ectasia .
Ectasia creates special challenges in the Interventional era. Stenting an ectatic segment confers a real danger , as these stents are prone for dislodgement or even collapse into the lumen or migrate downstream triggering an ACS. In fact , such complications of PCI are never recognised and hence not reported.
Final message
Coronary artery dilatation is also an important pathological state like coronary stenosis . Since it rarely limits the blood flow in isolation , it is a less respected lesion.
But , interventional cardiologists beware : PCI in a ectatic vessels can give you (And your patients too !) sleepless nights .
Treatment of isolated ectatic segments is controversial .Less aggression is always better . CAD risk factor profile management is adviced . If severe ectatic changes are present it is a good practice to add oral anticoagulants like Warfarin. Surgical excision of aneurysm is rarely required.
Kawasaki disease is a distinct entity that need to be addressed separately in pediatric population.
Dr.S.Venkatesan MD 
