Chronic total occlusion revascularization: A complex piece to "complete" the puzzle

Table 2 Main scores for assessment of chronic total occlusions

	J-CTO score		CL score		ORA score		PROGRESS score		RECHARGE score		EURO-CTO CASTLE score
Angiographic Features	Proximal cap blunt	1	Proximal cap blunt	1	Ostial location	1	Proximal cap ambiguity	1	Proximal cap blunt	1	Proximal cap blunt	1
	Tortuosity > 45°	1	Lesion lenght > 20 mm	1.5	Collateral filling Rentrop 0-1	2	Tortuosity	1	Tortuosity > 45°	1	Tortuosity > 45°	1
	Lenght > 20 mm	1	Calcification	2			Circumflex CTO	1	Lenght > 20 mm	1	Lenght > 20 mm	1
	Calcification	1	Non-LAD CTO	1			Absence of interventional collaterals	1	Calcification	1	Calcification	1
									Diseased distal landing zone	1
Clinical features	Prior CTO PCI failure	1	Previous MI	1	Age > 75 yr	1			Previous CABG on CTO target vessel	1	Previous CABG	1
			Previous CABG	1.5							Age > 70 yr	1

Japan-chronic total occlusions (CTO) score (45): 1 point for the presence of each variable with classification into 4 categories of difficulty: Easy (0), intermediate (1), difficult (2), and very difficult (≥ 3). Clinical and lesion-CTO score (46): Non-anterior interventricular artery, previous MI, blunt stump (+ 1); previous coronary artery bypass graft, lesion length > 20mm (+ 1.5); severe calcification (+ 2). Four classes of probability of success are identified: High success rate (score 0-1), intermediate (score 2), low (score 3-4), and very low (score ≥ 5). PROGRESS-CTO score (47): 1 point for each variable. ORA score (48): 1 point for the variables of age and ostial location, and 2 points for the Rentrop collateral circle < 2; there are 4 degrees of difficulty: easy (0), intermediate (1), difficult (2), and very difficult (3-4). RECHARGE score (49): 1 point for each variable, grading CTO lesion complexity from 0 to 6 points. EURO-CTO CASTLE score (50): 1 point for each variable (0 to 6). At a score of 0, the mean predicted risk of failure of CTO percutaneous coronary intervention was 5.8%. At a maximum score of 6, the predicted risk of failure was 56.5%. CTO: Chronic total occlusion; CABG: Coronary artery bypass graft; LAD: Anterior interventricular artery; LCx: Circumflex artery; MI: Myocardial infarction.