ABC | Volume 110, Nº5, May 2018

Review Article Ybarra et al CTO PCI Review Arq Bras Cardiol. 2018; 110(5):476-483 Figure 1 – J-CTO score: angiographic score used to estimate the probability of success of the procedure. Five variables were analyzed: proximal cap (tapered or blunt), presence of calcification in chronic total coronary occlusions (CTO), presence of angulation greater than 45 degrees within the CTO segment, length of occlusion (greater or equal to 20 mm) and unsuccessful previous approach attempt. The degree of difficulty of the procedure increases the greater the J-CTO score. 16 Tapered Blunt (0) (1) Entry shape Absence Presence (0) (1) Calcification Absence Presence (0) (1) Bending > 45° < 20 mm ≥ 20 mm (0) (1) Occl.Length No Yes (0) (1) Re-try lesion Variables and definitions J-CTO SCORE SHEET Tapered Blunt Calcification Bending > 45 degrees Occlusion length Re-try lesion Regardless of severity, 1 point is assigned if any evident calcification is detected within the CTO segment. Entry with any tapered tip or dimple indicating direction of true lumen is categorized as “tapered”. point point point point point points Total One point is assigned if bending > 45 degrees is detected within the CTO segment. Any tortuosity separated from the CTO segment is excluded from this assessment. Using good collateral images, try to measure “true” distance of occulusion, which tends to be shorter than the first impression. Is this Re-try (2nd attempt) lesion> (previously attempted but failed) Category of difficulty (total point) easy difficult Intermediate very difficult (0) (2) (1) (≥ 3) Version 1.0 angiographic evident calcification within CTO segment CTO segment > 45° at CTO entry at CTO route bending > 45° within CTO route estimated CTO route collateral true occlusion length dedicated equipment was associated with lower rates of major cardiovascular events (MACE) (4.3 vs . 15.4%, p = 0.02) and target vessel revascularization (3.1 vs . 15.5%, p = 0.02) when compared to older techniques. 27 Retrograde technique The retrograde approach to CTO crossing can significantly increase success rates, particularly in more complex lesions. It is considered the first line strategy when the proximal cap is ambiguous, the antegrade reentry zone is not adequate or the distal cap ends at a bifurcation. Retrograde crossing by grafts (especially venous grafts) and by septal collaterals are preferred to epicardial collaterals because they are easier to traverse and present lower risk of tamponade in case of perforation or rupture. 28,29 Through a collateral, the guidewire proceeds to the distal region of the occlusion and, from this point, the CTO is crossed in the opposite direction to the blood flow. 30 Retrograde crossing by the true lumen is generally easier, once that the distal lumen tends to have more favorable (softer, pencil-like, less ambiguous) characteristics than the proximal one. 8 If true lumen crossing is not possible, dissection and re-entry techniques, other than anterograde techniques, may also be applied. Choice of stents Intra-stent restenosis after CTO PCI with conventional stents was of approximately 50%, which practically prevented its use in this scenario. With the drug-eluting stent implantation, clinical outcomes improved significantly, leading to lower restenosis rates (relative risk: 0.25, 95% CI: 0.16-0.41, p < 0.001), reocclusion (relative risk: 0.30, 95% CI: 0.18-0.49, p < 0.001) and new target vessel revascularization (relative risk: 0.40, 95% CI: 0.28-0.58, p < 0.001). 31-34 Thus, the use of drug-eluting stents became mandatory. 478