Near but Far Away! A Rock Blocking Antegrade and Retrograde Catheters!
Dr. Yu-ho CHAN
Case Summary
75 M, with history of diabetic mellitus, was recently admitted for NSTEMI with cardiogenic shock. PCI was done for the culprit lesion from LM to proximal LAD. A double CTO lesion was noted over the middle to distal RCA (Movie 1). Staged procedure was arranged because echo showed features of viable inferior wall myocardium.
The mid RCA CTO lesion was calcified with ambiguous proximal cap, angulated with 45 degree. A big side branch was located next to proximal cap. For the distal RCA CTO lesion, the proximal cap was also not clear.
Procedure
AL1 and EBU 3.5, both 7Fr guiding catheters were chosen.
Proximal cap management:
Because the proximal cap was calcified and located centrally on the vessel by IVUS assessment. Conguest pro 12 supported by Turnpike was used. Puncture position was confirmed by IVUS again. Step down approach was performed using Fielder XTA but the wire went into the subintimal space (Figure 1).
Retrograde approach and channel crossing:
After analyzing the septal channels, retrograde approach was proceeded, after antegrade approach/preparation. Sion wire was passed to the 1st septal channel. The old proximal stent strut was opened by Sapphire II pro 1.5/10. Selective injection was done. A Suoh 3 wire with tip load of 0.3g was chosen to negotiate with the channel in this case (Movie 2,Movie 3). For crossing the channel, we often need to adjust the position between the wire tip and the micro-catheter with careful advancement of the wire tip, so that we can adjust the forward force of the wire tip and maintain wire control.
Suoh 3 was unexpectedly able to cross the distal RCA CTO lesion. This signified there was a micro-channel over the RCA CTO. The choice of wire was stepped up to Fielder XTA, and retrograde turnpike LP was advanced. Fielder XTA can provide both better penetrating force and wire control. However, the retrograde Turnpike LP was not able to advance further up to mid RCA because of heavily calcified distal RCA lesion. Eventually, two CTO wires were placed close to each other at middle RCA (Figure 2). Reverse CART was the next step. One of the key steps of success of Reverse CART technique is to know the antegrade and retrograde wire positions. IVUS is definitely helpful for such assessment. In our case, the retrograde wire was found in the subintimal space and antegrade wire was found in the true lumen. Therefore, a balloon size of 1:1 vessel was chosen for both Reverse CART and tripping the retrograde wire for advancement of retrograde turnpike LP (Figure 3). Without further advancement of microcatheter into the antegrade guiding catheter, it was almost not possible to finish the procedure.
After spending some time at the step of XCART, the retrograde wire was changed to a more controllable wire, Gaia 2nd. It was externalized into antegrade guiding using Guinderliner Reverse Cart technique (Movie 4). However, the retrograde Turnpike LP was still not able to be advanced. It made the changing of retrograde wire to RG3 for externalization not possible.
If retrograde micro-catheter could not cross, how can we solve?
When the retrograde micro-catheter was not able to cross because of heavily calcified lesion, we can consider to use certain methods to enhance the support of retrograde wire, or explore how to reduce the resistance of the calcified lesion (Figure 4).
Trapped balloon technique is an initial choice. In most situations, it can greatly enhance the support of retrograde wire. Sometimes, we can pull the retrograde wire a little bit in order to further enhance the support. It usually works in most situations. However, occasionally, we may need to consider using a new microcatheter with lower profile, e.g. Caravel or new Turnpike LP, especially when the tip of used Turnpike LP head may become minimally distorted during rotation against the hard-calcified cap or lesion. Retrograde balloon dilatation over the site of the stall is another solution. If we want to proceed with retrograde balloon dilatation, we should choose an over-the-wire small size balloon because rapid exchange semi-compliant balloon may damage the retrograde septal channel during negotiation (especially when the rapid-exchange-balloon may create a space between the wire and the balloon during negotiation over the septal channels), resulting in perforation of the channel. Retrograde balloon was not considered in our case as the channel was tortuous and small over the distal part as shown (Movie 2,Movie 3).
Trapped balloon was tried in our case but it did not work; neither for the new Corsair Pro.Movie 5 showed the retrograde Corsair Pro was not able to be advanced even with the strong support of trapping balloon inflation over the antegrade guiding catheter.
Rendezvous Technique
When facing such unfavorable and hard situations, we could also step back and review all the possibilities. When retrograde approach was not working, we could actually consider antegrade approach again. The antegrade guiding catheter chosen was AL1 with active backup support. Antegrade support would be better than retrograde guiding support. Therefore, antegrade microcatheter may able to pass the calcified lesion but how to do?
Rendezvous technique was used to advance an antegrade microcatheter over the retrograde wire (Movie 6). Rendezvous technique is basically advancing the retrograde wire into antegrade microcatheter directly over the guiding catheter. Because the opening of the microcatheter is tiny, a controllable wire e.g. Gaia 2nd or UB3 should be considered for such methods. A new Turnpike Spiral was advanced over the retrograde wire eventually. With its screw design, we can advance the catheter into calcified lesion with rotating force (Movie 7).
However, in our case, the proximal CTO lesion, mid RCA one, was also hard. Turnpike Spiral was also not working despite the active backup support from AL1. Again, if microcatheter could not cross the lesion, the principle is similar to that of non-crossable retrograde micro-catheter (Figure 5).
Movie 8 showed advancement of antegrade Turnpike Spiral but it could not cross the distal calcified CTO lesion, with support of an anchoring balloon. Mother-Child method using Guideliner was attempted. In order to insert a Guideliner, Rendezvous technique was performed again. Turnpike Spiral was replaced by Turnpike Gold (Movie 9). However, it was still not possible to further advance the Turnpike Gold into the distal CTO lesion, even with such extensive support.
Near but far away! Back to basic wire-based technique
At the moment, the two catheters were so close but not able to pass through the calcified lesions from either side. We can remember Suoh3 wire was able to cross the micro-channel of the distal RCA CTO lesion, with certain advancement of retrograde mirco-catheter in the previous step. It means the true lumen of distal RCA CTO lesion should have been expanded (Figure 6)!
Loose tissue tracking is another important technique. At that moment, we have done proximal cap modification by advancement of antegrade Turnpike Gold. However, further advancement was not possible because of heavily calcified lesion. Therefore, a step-down approach using Fielder XTA wire was used. The retrograde microcatheter served as a target for the wire to go. Eventually it was able to track through the expanded retrograde micro-channel created by SUOH3 and Retrograde Turnpike LP before (Movie 10)! The wire finally passed through the distal CTO lesion and entered into true lumen at distal RCA (Figure 7). Both CTO lesions were then crossed and predilated by a low profile 1.0 semi-compliant and a 1.5 semi-compliant balloon.
The rest of the procedures became relatively simple, namely scoring balloon pre-dilatation, non-compliant balloon inflation for calcium cracking, IVUS guided stenting and optimization.
The final angiographic result and clinical result were excellent after the procedure (Movie 11).
Conclusion
CTO intervention is a challenging procedure that requires precision and decisiveness. It is always good to have thoughtful planning. Wire based approach using escalation de-escalation method and antegrade-retrograde approach are essential techniques. When the micro-catheter is not crossing the lesion, anchoring technique, mother-child method and combination of methods should be considered.