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 !
