• Generally the Left Main gives rise to the Left Anterior Descending Artery and the Left Circumflex Artery
• However, some times, these 2 arteries can have separate origin with absence of the Left Main artery
• This patient presented with angina
• At angiography, he was found to have a mid LAD CTO
• The LCx which has a separate origin and gives collateral to the LAD by joining the OM1 to the 2nd Diagonal

The following series shows the baseline angiogram
An AL2 cannulated the LCx and EBU 3.5 cannulated the LAD

• This angiogram shows the collateral coming from OM1 and it joins the Diagonal

• Using a Fielder XT wire in a long Corsair, I tried to cross the epicardial collateral

• The Corsair injection shows the collateral has been successfully crossed
• The corsair is now sitting in the LAD

• Placing a Runthrough in the LAD in the antegrade position provides a target for the retrograde wire to aim
• Now the retrograde wire has crossed the CTO portion and entered the septal

• After sequential balloon dilatation, the LAD can now be seen throughout its length

• This angiogram shows the retrieval of the retrograde wire after an antegrade wire has been passed down the LAD

• Due to the presence of some calcification, the stent could not be easily delivered
• So a Guideliner was placed in the proximal LAD
• A long stent can now be delivered to dLAD

• A second stent was place in pLAD with distal overlap

• This is the final angiogram after successful stenting

Conclusion

• The Left Main is a variable length artery
• Sometimes as in this case, it is non-existence
• Instead, the LAD and LCx have separate origins from the aorta
• In this case, the LCx was supplying collateral from the OM1 branch to the LAD via the diagonal
• Generally, epicardial collateral are more fragile for retrograde crossing
• Since in this case, the RCA does not provide any septal collateral the OM1 epicardial serves as the only retrograde channel
• However, generally more care should be exercise when crossing epicardial channel