Retrograde Approach “Reverse CART Technique” with a Single Guiding Catheter for Chronic Total Occlusion of the Right Coronary Artery Via an Anomalous Left Circumflex Artery

Case Report. A 67-year-old man with a history of peripheral artery disease was referred to our department for a severe silent ischemia in the inferior wall revealed in a systematic myocardial scintigraphy. His cardiovascular risk factors were dyslipidemia and current smoking.

The coronary angiography revealed a chronic total occlusion (CTO) of the mid-portion of the right coronary artery (RCA) (Figure 1A). The left anterior descending (LAD) was normal and provided only faint collateral circulation to the RCA. The left circumflex artery (LCx) was not found. An initial attempt to open the occluded lesion was made via the anterograde approach, but unfortunately failed.

A coronary multislice computed tomography (MSCT) was performed (Figures 1B–1D) and revealed an anomalous origination of the LCx arising from the ostium of the RCA (Figure 1B, white arrow and Figure 1D, black arrow). There was complete left-to-right collateral filling from the ectopic LCx through the posterior descending artery (Figure 1D, white arrow).

For the second CTO attempt, the RCA was engaged with a 6 French (Fr) JR 4 guiding catheter, which allowed both anterograde and retrograde injection through the ectopic LCx (Figure 2A). A 180 cm Fielder FC guidewire (Abbott Laboratories, Santa Clara, California) was loaded into a 2.6 Fr, 150 cm Corsair microcatheter (Asahi, Japan; Figure 2B, white arrow) and this system was retrogradely advanced into the distal cap of the mid-RCA occlusion via the LCx (Figure 2C). The wire was then changed for a 180 cm, soft polymer-coated wire (Fielder XT; Abbott Laboratories). We approached anterogradely with a Pilot 50 wire (Abbott Laboratories) into the proximal cap of the occlusion (Figure 2D). The ˝reverse controlled antegrade and retrograde subintimal tracking (CART) technique˝ was intentionally used for subintimal tracking (Figures 3A–3C); we performed anterograde balloon dilation with a 2.5 x 15 mm Sprinter (Medtronic, Minneapolis, Minnesota) in the proximal cap of the occlusion. Next, the retrograde Fielder XT wire was successfully advanced in the anterograde space. Then, the anterograde Pilot 50 wire successfully crossed the subintimal space and was finally placed in the true lumen of the distal RCA. After additional anterograde predilation, 3 drug-eluting stents (3 x 28 mm, 3 x 28 mm and 2.5 x 28 mm Taxus Liberty stents; Boston Scientific, Natick, Massachusetts) were deployed from distal to proximal RCA with a good final angiographic result (Figure 3D).

Discussion. Percutaneous coronary intervention (PCI) of CTO is one of the major challenges in Interventional Cardiology. The primary success rate is relatively low compared with non-CTO lesions, mainly due to inability to cross the occlusion with the guidewire. However, over the last 15–20 years, technical and procedural success rates and long-term outcomes have improved, along with the increased experience and skill of the operators, the availability of new specialized guidewires, microcatheters or more sophisticated technologies for crossing occluded arteries, and the widespread use of drug-eluting stents.^1,2

Retrograde approach through the collateral channels has been recently proposed and has the potential to improve the success rate of PCI in CTO lesions.³ Usually, this strategy is performed after previous failed attempt(s) via the anterograde approach, with the presumption that the distal cap of the CTO lesion may be softer than the proximal cap. Several strategies in a retrograde approach may be proposed to cross the occlusion, according to the CTO lesion characteristics, and sometimes, a very complex CTO lesion may require a combination of several techniques.^4–7 The reverse CART technique has been shown to be safe and feasible, with a high success rate when performed by highly experienced operators.^4–7 This technique engages a guidewire retrogradely in the distal cap of the CTO and advances another one anterogradely in the proximal cap of the CTO. The retrograde wire is advanced in the subintimal space into the CTO lesion. The subintimal channel is enlarged by advancing and inflating an anterograde balloon in order to create a plaque dissection and modification of the lesion. Then the retrograde wire is advanced to cross the dissection and link up with the anterograde wire positioned in the proximal true lumen. Next, the retrograde wire is externalized through the guiding catheter and is used for subsequent anterograde angioplasty. In our case, because of the anomalous LCx originating from the ostium of the RCA, despite a lack of support, we had to use the same guiding catheter for both anterograde and retrograde approaches. Therefore, we could not externalize the retrograde wire, which was then used as a marker to help the anterograde wire to cross the occlusion through the subintimal space. To our knowledge, this is the first reported case of successful PCI of an RCA occlusion via an anomalous LCx originating from the RCA. This case was very challenging because it utilized both anterograde and retrograde approaches (reverse CART technique) through a single guiding catheter.

Furthermore, this case utilized non-invasive imaging by multislice computed tomography (MSCT), not only for assessing the calcified nature and the length of the occlusion, but also to optimize the visualization of collateral circulation which may be incorrectly estimated by conventional angiography.^8,9 In our case, MSCT was very helpful to emphasize the particular anatomy of anomalous LCx which originated from the ostial RCA and provided the main collateral filling to the distal part of the occlusion.

References

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