The use of IVUS in CTO


The use of IVUS

  • IVUS or Intra-Vascular UltraSound
  • Is commonly used during Percutaneous Intervention
  • It looks at the inside of the blood vessel giving information on vessel size and plaque volume for example
  • It also helps to identify the origin of the side and where the PCI wire is sitting

1st Case

  • This is a case of CTO of the LAD starting from the ostium
  • This case was done in the earlier days when retro-grade approach was just taking hold
  • In the early days, the use of IVUS was not well established and the equipment were not as advance as they are today
  • This case was performed without ante-grade preparation nor IVUS guidance
  • This is a negative example of how ‘not’ to do things!

This bilateral injection in the spider view shows the beginning of the occlusion

This cranial view shows collateral coming from the RCA

Before the days of IVUS and Gaia and Corsair

  • 6F AL1 forRCA. EBU 3.5 for LAD. These were the days of Miracle 3 & 12 in Finecross micro-catheter
  • The retro-grade wire was brought up close to the ostium of the LAD
  • From the RAO cranial view, the wire appears to be in a good position

However, in the spider view it doesn’t look so good
Without antegrade guidance, the path of retro-grade wire was no directed correctly

The result can be nerve wrecking!
The contrast injected into the Finecross catheter can be seen exiting into the aorta

The contrast is seen going into the aorta from Finecross
An Aorto-coronary fistula was created
The procedure was abandoned and patient was sent for bypass surgery However, if this case was done today, a 2nd attempt with IVUS guidance would almost guarantee success

Here is another case of LAD ostial CTO

  • This case was performed more recently
  • This time IVUS was used together with antegrade wire guidance
  • IVUS was used to identify the LAD ostium and a wire placed there
  • Then retro-grade approach started
  • IVUS was used to identify that the retro-grade wire entered the true lumen of Left Main

This baseline angiogram in the caudal view shows the LAD occlusion

  • 6F EBU 3.5 guide and 6F JR4 diagnostic was used to perform bilateral injection

The collateral from RCA could be easily seen

Going up the RCA collateral wasn’t too difficult
A Runthrough wire could enter and traverse the RCA septal collateral easily

The retro-grade wire has crossed into the LAD and the Runthrough exchanged for a stiffer wire for crossing

In the spider view the wire appears to have reached the left main artery

IVUS was placed in Left Main to visualise the wire
In the AP caudal view, the wire also appears to be inside the left main


However, the IVUS showed that the wire was in fact embedded in the sub-intimal space of the left main and is not in the lumen


The wire was repositioned and IVUS used to check the position again


The entrance can now be seen

  • The XT-A was changed out to RG3
  • After initial ballooning
  • The ostium of LAD can be seen
  • Stenting of the LAD was then performed and the case was completed successfully

The next case is LCX CTO

  • This case was attempted in another institution but failed
  • After talking to the patient, a reattempt was made
  • This case will illustrate the use of IVUS in identifying ostium of side branch

This is a LCx CTO

  • 7F AL 2 Short Tip was used to cannulate the Left Main
  • This angiogram shows the site of occlusion and a very dominant LCx distally
  • It also shows collateral coming from LAD septal

This LAO cranial view shows the distal LCx clearly

After initial ballooning

  • XT-A, Gaia 2nd in Corsair were sequentially used to cross the CTO
  • 2.0 balloon was used for pre-dilatation
  • OM2 is well seen
  • But OM1 ostium is not obvious
  • IVUS was used to identify the ostium and entered with XT-A

  • After entering the OM1
  • IVUS pull back was used to verify the correct entrance of the XT-A into OM1





  • Stented LCx and OM1

From the AP cranial view, the whole LCx can be clearly seen

The next case is a distal RCA CTO

  • There is a short segment of CTO in distal RCA
  • Then a short segment after the CTO but proximal to the PDA is supplied by collateral
  • After which the AV groove segment is completely occluded again at the crux
  • This case will illustrate the usefulness of IVUS in determining the placement of after crossing CTO

The baseline angiograms shows the CTO

The CTO was crossed with Ultimate Bro 3 in Corsair and then changed out to Runthrough
The wire is seen sitting in a branch of PDA

Is there a split in dRCA/PDA junction?

  • Pre-dilated PDA with 2.0 balloon and crossed AV groove with Ultimate Bro
  • Dilated AV groove with 2.0 balloon
  • This is the angiogram after the pre-dilatation
  • Pay attention to the crux

Split into AV groove vs PDA

  • Who is in the true lumen?
  • The AV groove wire or PDA wire?
  • IVUS pullback from distal RCA





The thin tissue between the 2 wires can be seen on IVUS

  • If a stent were to be placed on the AV Groove wire, the PDA will be occluded after the deployment of the stent
  • Similarly if the stent were to be placed on the PDA wire, the AV Groove vessel will be occluded upon deployment of the stent
  • Therefore readjustment of the PDA wire is necessary

Readjusted the PDA wire, verified with IVUS
The sliver of tissue between the wires are no longer seen

On IVUS, the PDA wire can be seen entering the AV Groove now without separation



Stented RCA into PDA 3.0 x 48 & treated AV groove with DEB


  • Other than assessing vessel size and stent apposition
  • IVUS is a valuable tool for identifying CTO ostium especially when the entrance is flushed with main branch
  • Useful in identifying true lumen from sub-intimal space