This, the Silent War – Antegrade for CTO without Stump, Balloon Wire Fusion & Use of Complication
Dr. Ho LAM
Case Summary
Patient was 57 years old gentleman, who had history of IHD, Gout, HT and OSA. CT coronary angiogram showed ostial LAD CTO with calcium score 1422. (Figure 1)
Coronary angiogram of the patient showed the same finding of ostial LAD CTO with retrograde filling from the RCA. The lesion was heavily calcified and with length > 20mm and angulated. Stump was absent in coronary angiogram. J CTO Score = 4.
For PCI to CTO without stump by antegrade approach, careful review information from IVUS, CT coro and coronary angiogram is very important. Major factors affecting the approach includes the angulation, presence of small channels on stump & consistency of stump. (Figure 2)
The coronary angiogram as showed on Movie 1 and Movie 2.
Precise entrance of the proximal cap in calcified CTO without stump is the essential factor for a successful procedure. After failing to enter the proximal cap by attempting with different wires, a 1.5mm small balloon was inflated at the ostium of side branch next to the CTO proximal cap, in order to block the entrance to side branch. This approach increased the support of the guiding catheter so that a softer wire with tailored shape can be used to find the channel shown on CT coro precisely. Those channels cannot be shown in IVUS most of the time. Thus pre procedure CT coro was more helpful. For this case, Fielder XT-A after special shaping was used. (Movie 3) If there was absence of channel, the approach will be different.
After seeding the wire tip into the CTO stump and confirmed by biplane or IVUS, then the corsair is carefully advanced into the CTO stump (Movie 4). This step required the use of a microcatheter with soft tip to accommodate the angulation. Further advancement of the special shaped wire is not recommended. Sub-intimal entrance is common.
When the corsair locked in the CTO stump, “step up wire” approach was used in this case because the CTO body was extremely hard. Usually, the locked-in corsair in calcified lesion will provide very good support for wiring and hence Gaia 2 was used. Focus of operator will be on keeping the wire in the true lumen by wire feel, visualization and planned imagination line before wiring. Turning of wire should be clockwise and anticlockwise alternatively and feeling the wire during slow advancement and its movement is visualized at the same time to avoid entrance to the sub-intimal space. When wire travelled to mid-way of the planned imagination line, contralateral injection is recommended so that adjustment of the imagination line, angle and expected distal cap location can be done. (Movie 5, Movie 6)
Distal cap puncture is another key element. Usually, when wire travelled to the distal cap in the imagined line and visualized location by contralateral injection, slight increase in resistance in wire tip will be felt. It may not be always be present. Then clockwise and anticlockwise movement of the wire gently to feel the cap and adjusting the wire in correct direction before puncturing the distal cap is highly recommended. Frequently failure will occur in the distal cap puncture. The distal cap puncture was recorded in Movie 7.
Most of time after distal cap puncture, there is a special “give away” feeling so the wire has to be stopped and checked before further advancement to avoid entering a false lumen.
Biplane angiogram was used to confirm the wire was in the true lumen. (Movie 8, Movie 9)
However, the corsair was advanced with great difficulty due to the heavily calcified CTO body. During drilling of the corsair, the gaia 2 wire was shifted into sub-intimal space despite careful control. (Movie 10)
Redirection by using various wires and multiple attempts failed (Movie 11). IVUS guided rewiring was not possible because it was impossible to insert into the lesion. The use of ADR was not considered by expert due to high failure rate from heavy calcification & small target distal vessel. Retrograde approach was suggested.
At the stage of failure in wire redirection, it is important to keep claim. Careful evaluation of the whole procedure from patient’s clinical history, lesion anatomy and mechanism of failure for twice was recommended. For this case, the Gaia wire was once in true lumen and the cause of sub-intimal entrance was due to advancement of corsair. Wire entered false lumen at a location just after passing the CTO body. So, most of the pathway in the CTO body should be in true lumen. The correct redirection approach in this case should be withdrawal of the corsair in area around the proximal cap in order to give more space for the soft wire to move and search for the prior created pathway.
Hence, the approach was adjusted based on mechanism of failure. Corsair was withdrawn back to proximal LAD, instead of keeping in mLAD which limited the wire redirection. Fielder XT – A was used to search for the previous distal cap entrance site. The key for success is “no pushing force” and let the wire to find the way by itself.
Finally, LAD was successfully rewired (Movie 12).
The lesion was heavily calcified. Corsair cannot cross and Sapphire 1.0 and 1.5 cannot cross the lesion.
Rupture balloon method by Sapphire 1.5 balloon was used. However, the balloon did not rupture at 20 ATM. Instead, it was complicated by balloon wire fusion. The central lumen of the balloon catheter collapsed and fused with the wire. Handling this complication was a silent war. When the balloon was withdrawn, both wire and balloon moved out together. To overcome this complication, the balloon was withdrawn 1-2 cm while the wire had to be advanced 1-2cm by drilling. Finally, the balloon was slowly removed bit by bit. It was lucky the wire was Fielder Series otherwise total loss of wire was the likely consequence.
After that, Sapphire 1.0 can cross the lesion and later corsair crossed too. This was likely due to prior manipulations. The wire was exchanged into BMW Universal II.
However, during predilation of the mLAD lesion, the balloon failed to open up the lesion. NC Euphora 2.0 cannot dilate the lesion at 26 ATM despite repeated ballooning. (Movie 13)
Rotablation was the usual approach in this situation. Due to cost concern and part of the vessel at distal end of CTO body was dissected; we used another alternative method after discussion. There was some theory to state that rotablation of dissected distal cap of CTO lesion may increase risk of spiral dissection when the burr moved through the calcified lesion, especially when burr speed was reduced by friction before exit.
Rupture balloon method plus OPN ballooning approach was used to introduce dissection and further prepare the lesion at the same time. The NC Euphora 2.0 was inflated to 30 ATM and was ruptured to cause dissection in the lesion. (Movie 14) After dissection, some non- dilatable lesion will become dilatable. OPN 2.0 was inflated to 35 ATM. Full expansion of balloon was demonstrated. This is not a usual approach but it is a good case to demonstrate how to use procedure complication as a means of treatment in PCI. This method has been reported in ESC 2017. Usage needs courage and backup plan.
Lesions were stented with Synergy stents. Final angiograms were good (Movie 15, Movie 16).
Conclusion
Due to advancement of equipment, most of CTO can be done in antegrade approach with more than 80% success rate at least. Wiring approach should be based on patient clinical condition, lesion characteristics and procedure analysis. Imagination line, wire feel, and visualization are the 3 keys elements after establishing wiring approach.
Also, complication is not always our enemy. We prevent it, we treat it and sometimes we use as in this case!