Is it not , boring to see normal coronary arteries every day ! There need to be surprises in cath lab to make our time lively and keep our brain alert . Have a look at this angiogram in RAO caudal view.One of our junior cardiology fellows thought it was a split left main artery .
How can an artery split . . .of course the image indeed looks like that !
It was indeed an absent left main. Also called as separate origin of LAD and RCA.
Note : There can be three types of absent left main.
- LAD and LCX from same ostia on the left coronary sinus*
- LAD and LCX separate ostia but both from same sinus**
- LAD from left coronary sinus, LCX from right sided sinus (Probably the common type )
* Some books mention about a left main of 0 -5mm .
** Very difficult to delineate and is rare
Zero mm left main is nothing but single ostial origin of both LAD and LCX. A very short left main , say 1 0r 2 mm will practically mimic an absent left main.
Here is the the dynamic angio image. It is surprising how a catheter in left sinus is able to visualise the LCX from right sinus so well !
Note the separate origin of LAD and LCX.The LCX was originating near the right sinus.It is intriguing to note even though they originate in different sinuses , the main stem of LAD and LCX wants to maintain a close parallel relation.
Advantages of having absent left main .
- It requires no great brains , to predict the above patient is immune to develop Left main or true bifurcation disease
- Sudden death is presumed to be less common in this population.
Implications for interventional cardiologists
Guiding catheter selection and positioning could be difficult.
Dr.S.Venkatesan MD 