Attack of the clones


  • This is the AP cranial view showing the proximal LAD CTO
  • The entrance into the LAD is not obvious
  • There is a septal and diagonal branches at the end of LAD making it hard to enter the LAD ante-gradely

Bilateral dye injection shows the short gap of occlusion

After crossing the septal channel deep injection into the Corsair shows a small track

  • Placing an IVUS in the diagonal, the LAD could be identified
  • The UM3 wire can be seen to enter the LAD

Antegrade injection of dye seems to indicate that the wire is in

From the spider view the retrograde wire looks satisfactory

This is what the IVUS shows

The wire was pulled back and readjusted

The IVUS now shows this

Let us look at the screen grab of the 2 IVUS runs

  • They may look the same but they are not clones
  • We shall examine the IVUS pullback from the Diagonal starting before the LAD joins the Diagonal until the proximal LAD

This is from the 1st run

This is from the second run

The 1st IVUS run

  • At this moment, the IVUS is in the diagonal and the LAD is coming into view at 7 O’clock
  • The wire is in the sub-intimal space and is not in the LAD lumen

The 2nd IVUS run

  • For the 2nd run after adjusting the wire, it can be seen sitting inside the lumen

As the pull back continues, the wire continues to be seen in the subintimal space all the way until the IVUS enters LAD


As the pull back continues in the 2nd run, the wire stays within the lumen all the way back to the LAD



  • After verifying that the wire is truly in the LAD, pre-dilatation and stenting were performed
  • The LAD was stented with single 3.5 x 48mm stent from the ostial LAD
  • The final angiogram shows the treated vessel

Final angiogram from AP Cranial view


  • Here is another case showing the usefulness of using IVUS to identify whether retrograde wire has entered the lumen after crossing the CTO segment
  • This is specially useful in proximal LAD lesion
  • If the wire was pushed forcefully forward, it may dissect the Left Main or enter the aorta via the sub-intimal space