Scoring system | Published year | No. of CTO patients | Primary endpoint | Predictors | Predictability |
J-CTO | 2011 | 465 | Guidewire crossing within 30 minutes | 1) Entry shape (1) 2) Calcification (1) 3) Bending > 45˚ (1) 4) Occlusion length (1) 5) Re-entry lesion (1) | 1) Easy: Score 0 2) Intermediate: Score 1 3) Difficult: Score 2 4) Very difficult: Score ≥ 3 |
CT RECTOR | 2015 | 240 | Guidewire crossing within 30 minutes | 1) Multiple occlusions (1) 2) Blunt stump (1) 3) Severe calcification (1) 4) Bending > 45˚ (1) 5) Second attempt (1) 6) Duration of CTO (1) | 1) Easy: Score 0 2) Intermediate: Score 1 3) Difficult: Score 2 4) Very difficult: Score ≥ 3 |
CL | 2015 | 1657 | Procedural success defined by < 30% residual diameter stenosis with TIMI grade 3 | 1) Severe calcified lesion (2) 2) Previous CABG (1.5) 3) Lesion length ≥ 20 mm (1.5) 4) Previous MI (1) 5) Blunt stump (1) 6) Non-LAD CTO location (1) | 1) High: ≤ 1 2) Intermediate: < 3 3) Low: < 5 4) Very low: ≥ 5 |
PROGRESS CTO | 2016 | 781 | Technical success defined by < 30% residual diameter stenosis with TIMI grade 3 | 1) Proximal cap ambiguity (1) 2) Absence of interventional collaterals (1) 3) Moderate/severe tortuosity (1) 4) Circumflex CTO (1) | The higher score, the lower technical success |
ORA | 2016 | 1073 | Technical success defined by final residual stenosis < 20% and TIMI grade 3 | 1) Ostial location 2) Rentrop collateral filling 3) Age | 1) Easy: Score 0 2) Intermediate: Score 1 3) Difficult: Score 2 4) Very difficult: Score ≥ 3 |
Ellis score | 2017 | 436 | Technical success defined by restoration of TIMI flow grade 3 and no stenosis > 50% | 1) Ambiguous cap proximal cap 2) Collateral score 3) Tortuosity 4) Calcification 5) Poor distal target 6) Length > 10 mm 7) Ostial location 8) Operator G | The higher score, the lower technical success |