Posts Tagged ‘left anterior descending artery’

LAD is  graded into three types according to

Type 1  :  Falls short  of Apex

Type 2 :   Reach up to the LV apex

Type 3 : Wraps around LV apex and travels some distance in the posterior Inter-ventricular groove.

Clinical  Importance of Wrap around LAD

As the name implies , LAD   should descend only in anterior aspect  in about 15 %  population it can take a posterior descending course as well .

When LAD  wants to conquer more areas of heart is it a clinical advantage  ?

When LAD wraps around the LV apex,  anterior MI due to LAD occlusions can show changes in inferior leads. (Antero Inferior MI )

In ideal anatomic /Physiologic conditions  LAD  should nearly  meet the  PDA   to prevent any water shed  area.

There is usually a trade off between the  terminal LAD and  length of PDA ( whether it arises from LCX or RCA.)

There is some evidence to  suggest the site of ventricular rupture in anterior MI is related to the gap  in the LAD/PDA drainage zones.

Patients with Type  1 LAD  are at risk of   LV apical  ischemia if the  dominant LCX /RCA is  not supportive .

Final message

A long LAD is definitely a  hemo-dynamic  advantage   in physiology ,   Of course  it goes  without saying    . . .   when  it’s   likely  to get  obstructed it is always better to have a Type 1 !

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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.

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