The retrograde technique has significantly improved the success of percutaneous treatment of chronic total occlusions (CTO). After crossing a collateral channel, creating a connection between the anterograde and retrograde systems is key. The most common technique for this is reverse controlled antegrade and retrograde subintimal tracking (reverse CART). This technique involves inflating a balloon over an anterograde guidewire, followed by the retrograde crossing of the occlusion toward the anterograde guidewire.
However, in some cases, this maneuver may fail. When that happens, after a failed reverse CART, the original CART technique (which involves retrograde ballooning of the occlusion followed by anterograde guidewire into the true distal lumen) could be a feasible alternative. Nevertheless, according to registries, its use in practice is limited (between 2% and 10.4%). The aim of this study is to assess the indications, procedural characteristics, and outcomes of this technique.
The study included patients who were subjected to a retrograde approach and the CART technique at a high-volume CTO center (University of Washington Medical Center). Researchers assessed technical and procedural success. CTOs were classified based on calcification and anatomical complexity using the J-CTO and PROGRESS-CTO scores.
Of the 1582 CTOs addressed over the study period, 38.1% required a retrograde approach. The original CART technique was used in 7.5% of those cases.
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The average age of the patients was 69.1±10.3 years; 93.3% of subjects were men, with an average ejection fraction of 53.6±10.1%. Additionally, 48.9% of the population had diabetes, and most patients had a history of angioplasty (84.4%) or myocardial revascularization surgery (68.9%). Treated CTOs were most frequently in the right coronary artery (48.9%) and 95.6% of the occlusions were over 20 mm long, with a prior failed attempt in 28.9% of cases.
On average, anatomical complexity was very high (J-CTO score of 3.6±0.9 and PROGRESS-CTO score of 1.9±0.7), with moderate to severe calcification in 95.6% of the cases. CART was used as the primary strategy in 42.2% of the cases. Its main indications were impenetrable CTOs in the anterograde direction (86.7%), failed reverse CART (28.9%), and aorto-ostial occlusions (11.1%). The collaterals used were venous grafts (62.2%), septal (24.4%), and contralateral epicardial collaterals (6.7%).
The CART technique was successful in 73.3% of the cases. Even when it was not, it facilitated a subsequent reverse CART in 41.7% of cases. Technical and procedural success was achieved in 85.7% of patients using a venous graft as a collateral and in 76.5% of cases in the No-Graft group.
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In the total cohort, the technical and procedural success rate was 82.2%, with a perforations rate of 8.9%, including both Ellis type 1 (balloon hemostasis) and Ellis type 3 (requiring a coated stent).
Conclusions
Data from the University of Washington show the use of CART in 7.5% of all analyzed retrograde approaches, with a high rate of technical and procedural success—despite high baseline anatomical complexity—and significant safety, as no in-hospital deaths were reported.
Dr. Omar Tupayachi.
Member of the Editorial Board of SOLACI.org.
Original Title: Controlled antegrade and retrograde subintimal tracking (CART) for recanalisation of chronic total occlusions.
Reference: Moscardelli S, Kearney KE, Lombardi WL, Azzalini L. Controlled antegrade and retrograde subintimal tracking (CART) for recanalisation of chronic total occlusions. EuroIntervention. 2024 May 10;20(9):571-578. doi: 10.4244/EIJ-D-23-01082. PMID: 38726716; PMCID: PMC11067721.
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