Table 1.
Clinical, Angiographic, Procedural Characteristics, and Outcomes in the Overall Study Population, Derivation Set, and Validation Set
| Variable | Overall | Derivation | Validation | P Value |
|---|---|---|---|---|
| Clinical characteristics | ||||
| Age, y | 65±10 | 66±10 | 65±10 | 0.35 |
| Age >65 y | 50 | 52 | 47 | 0.055 |
| Male | 84 | 84 | 85 | 0.57 |
| Body mass index, kg/m2 | 31±6 | 31±6 | 31±6 | 0.99 |
| Diabetes mellitus | 45 | 46 | 42 | 0.14 |
| Dyslipidemia | 95 | 95 | 94 | 0.42 |
| Hypertension | 90 | 90 | 89 | 0.57 |
| Prior myocardial infarction | 43 | 43 | 42 | 0.88 |
| Prior PCI | 66 | 64 | 68 | 0.13 |
| Prior CABG | 36 | 36 | 35 | 0.58 |
| Prior heart failure | 29 | 29 | 27 | 0.47 |
| Prior valve procedure | 3 | 4 | 2 | 0.11 |
| Cerebrovascular disease | 11 | 11 | 10 | 0.82 |
| Peripheral arterial disease | 17 | 15 | 19 | 0.061 |
| Chronic lung disease | 13 | 13 | 13 | 0.77 |
| Current tobacco use | 25 | 24 | 28 | 0.054 |
| eGFR, mL/min per 1.73 m2 | 72±26 | 72±25 | 71±27 | 0.67 |
| eGFR <60 mL/min per 1.73 m2 or currently on dialysis | 32 | 32 | 32 | 0.99 |
| Currently on dialysis | 3 | 3 | 4 | 0.31 |
| LV ejection fraction, % | 50±14 | 50±14 | 50±13 | 0.80 |
| LV ejection fraction <40% | 21 | 22 | 20 | 0.29 |
| Angiographic characteristics | ||||
| RCA target | 56 | 56 | 54 | 0.53 |
| LAD target | 23 | 23 | 24 | 0.72 |
| LCX target | 21 | 20 | 21 | 0.72 |
| Proximal segment target | 38 | 38 | 39 | 0.83 |
| Lesion length, mm | 30 (20‐45) | 30 (20‐40) | 30 (20‐50) | 0.63 |
| Length ≥20 mm | 77 | 77 | 76 | 0.92 |
| Length ≥23 mm | 66 | 66 | 65 | 0.92 |
| Proximal cap ambiguity | 32 | 31 | 33 | 0.62 |
| Side branch at proximal cap | 47 | 48 | 47 | 0.75 |
| Blunt/no stump | 53 | 54 | 52 | 0.51 |
| Distal cap at bifurcation | 32 | 31 | 33 | 0.47 |
| Good distal landing zone | 62 | 63 | 61 | 0.55 |
| Interventional collaterals | 59 | 60 | 57 | 0.41 |
| Moderate/severe calcification | 57 | 57 | 57 | 0.96 |
| Moderate/severe tortuosity | 36 | 36 | 38 | 0.45 |
| In‐stent restenosis | 15 | 14 | 17 | 0.16 |
| Prior CTO PCI attempt | 17 | 15 | 20 | 0.020 |
| J‐CTO score | 2.5±1.2 | 2.5±1.2 | 2.6±1.2 | 0.17 |
| PROGRESS CTO score | 1.3±1.0 | 1.3±1.0 | 1.4±1.0 | 0.13 |
| Procedural characteristics | ||||
| Radial access | 27 | 27 | 27 | 0.92 |
| Dual injection | 72 | 72 | 72 | 0.98 |
| Antegrade wire escalation used | 74 | 74 | 74 | 0.94 |
| ADR used | 35 | 35 | 34 | 0.65 |
| Retrograde approach used | 42 | 41 | 43 | 0.40 |
| IVUS used | 44 | 43 | 46 | 0.30 |
| Prophylactic LVAD | 2 | 2 | 3 | 0.45 |
| Procedural outcomes | ||||
| Technical success | 90 | 90 | 90 | 0.82 |
| Procedural success | 88 | 89 | 87 | 0.35 |
| Contrast volume, mL | 270 (200‐370) | 270 (200‐369) | 274 (200‐370) | 0.67 |
| Fluoroscopy time, minutes | 47 (29‐77) | 46 (28‐77) | 49 (30‐78) | 0.41 |
| Patient air kerma dose, Gy | 3.2 (2.0‐5.2) | 3.2 (2‐5.3) | 3.2 (1.9‐5.2) | 0.97 |
| Procedure time, minute | 129 (88‐192) | 126 (87‐192) | 139 (94‐199) | 0.052 |
| Periprocedural MACE | 2.8 | 2.6 | 3.2 | 0.54 |
| Death | 0.6 | 0.7 | 0.4 | 0.52 |
| Myocardial infarction | 1.0 | 0.8 | 1.6 | 0.12 |
| Re‐PCI | 0.3 | 0.2 | 0.4 | 0.44 |
| Emergency CABG | 0.1 | 0 | 0.2 | 0.15 |
| Stroke | 0.3 | 0.4 | 0 | 0.17 |
| Tamponade requiring pericardiocentesis | 1.0 | 0.9 | 1.0 | 0.92 |
Values are % or mean±standard deviation or median (interquartile range). ADR indicates antegrade dissection reentry; CABG, coronary artery bypass grafting; CTO, chronic total occlusion; eGFR, estimated glomerular filtration rate; IVUS, intravascular ultrasound; J‐CTO score, Multicenter CTO Registry of Japan score; LAD, left anterior descending coronary artery; LCX, left circumflex coronary artery; LV, left ventricular; LVAD, left ventricular assist device; MACE, major adverse cardiovascular event; PCI, percutaneous coronary intervention; PROGRESS CTO, Prospective Global Registry for the Study of Chronic Total Occlusion Intervention; RCA, right coronary artery.