The application of the J-CTO score for in-stent chronic total occlusion (CTO) recanalization remains unclear. We aimed to compare the role of J-CTO score in in-stent and de novo CTO interventions using wiring-based intraplaque tracking techniques. The application of the J-CTO score to assess procedural feasibility and guidewire crossing time for in-stent (N = 74, 14.6%) and de novo CTO (N = 434, 85.4%) interventions were evaluated in consecutive 508 patients (64.1 ± 11.6 years, 446 men). Failed intraplaque tracking (N = 3) or guidewires crossing (N = 35) was considered procedural failures (38/508=7.5%). The procedural success rate for de novo CTOs significantly declined when the J-CTO score was ≥3 (85 vs ≤2: 97%, p < 0.001), but was comparable for in-stent CTOs (≥3: 96 vs ≤2: 100%, p = 0.400). Among 470 patients with successful recanalization, the guidewire crossing time ≥30 minutes was required less for in-stent than for de novo CTOs (OR=0.40, 95% CI=0.18-0.86) with J-CTO score ≥2 in multivariate analysis. For those with successful antegrade-only wiring, the guidewire crossing time shown by Kaplan–Meier curves was significantly related to the J-CTO score for either in-stent (N = 72) or de novo (N = 370) CTOs (both p < 0.001 by log-rank test). However, only blunt stump (15.0 ± 5.6 min) and occlusion ≥20mm (16.2 ± 5.6 min) were independent time-determining factors of guidewire crossing (both p < 0.01) for in-stent CTOs. In conclusion, with the intraplaque guidewire tracking techniques, the effects of the J-CTO score on procedural feasibility and guidewire crossing time differ for in-stent and de novo CTOs. Therefore, the J-CTO score should be cautiously interpreted during in-stent CTO interventions.
Among CTO-PCIs, in-stent occlusion is a distinct category, and its incidence rate is approximately 15% in pooled data of 4 multicenter registries. For CTO-PCI, the Japan CTO (Multicenter Chronic Total Occlusion Registry of Japan: J-CTO) score was initially developed to grade the difficulty of crossing the occluded lesion within 30 minutes, and later to evaluate the feasibility of procedural success. The score has been subsequently applied to nearly all CTO-PCI studies including those comparing procedural features between in-stent and de novo CTO-PCIs. ,,,, However, the parameters of the J-CTO score were initially derived from native lesions, and the application of the scoring system to in-stent occlusions remains unclear. Furthermore, the comparable technique success rates between in-stent and de novo CTO-PCIs in the literature are based upon substantially diverse recanalization techniques or devices used for each group. For CTO interventionists, the easily visible stent contour significantly improves the accessibility of guidewire tracking through the vessel course of the CTO segment. Therefore, the rationale of wiring-based intraplaque crossing techniques is more distinct for in-stent than for de novo CTO-PCI. As the application of the J-CTO score to in-stent CTO-PCI with guidewire tracking techniques remains unclear, this study aimed to compare it with de novo CTO-PCI in terms of procedural feasibility and guidewire crossing time.
Methods
Study design and population
This prospective registry study was initiated and approved by the Ethics Committee of National Taiwan University Hospital (201904023RINC) in 2019. Retrospective data collection beginning in August 2014 was approved (201907064RIND). The period of retrospective data collection was determined by the introduction of the Gaia series (Asahi Intecc Medical, Japan) guidewires, which was designed more specifically for intraplaque tracking, in Taiwan. Written informed consent was obtained from the participants. From August 2014 to March 2023, 508 consecutive patients with CTO-PCI using intraplaque guidewire tracking techniques by our team in the National Taiwan University Hospital were enrolled for analyses ( Figure 1 ). In-stent CTO was defined as occlusion located within a previously deployed stent or within 5 mm proximal and distal to it. The presence of chronic kidney disease (CKD) was defined as an estimated glomerular filtration rate of <60 ml/min/1.73 m 2. Patients with congestive heart failure must meet the Framingham criteria with a left ventricular ejection fraction <50% before the index procedure.
The 508 cases with CTO interventions using wiring-based intraplaque tracking techniques. Successfully wiring was performed in 442 of 467 cases using antegrade-only techniques. Forty-one cases required the back-up of retrograde techniques, and 31 cases had successful recanalization. The 2 cases with reverse CART and one with knuckle wire techniques were considered failed intraplaque tracking. CTO = chronic total occlusion; CART = controlled antegrade and retrograde tracking; GW = guidewire.
Procedures of intraplaque guidewire tracking techniques
By coronary angiography, a CTO lesion was considered if the flow was thrombolysis in myocardial infarction (MI) grade 0 with a duration for at least 3 months. , Patients with multivessel disease had stenoses ≥50% in at least 2 major epicardial coronary arteries. The J-CTO score was based on the consensus of 2 independent operators (Dr. SC Liu and Dr. CL Lee).
The purposes of wiring-based intraplaque tracking techniques were to minimize the extent of subintima creation and stenting, and to preserve the antegrade flow for any side branch ≥1.5 mm from 5 mm before to 5 mm after the occluded segment in final coronary angiography. However, we did not intend to ensure a complete intraplaque course, but to achieve an acceptable final angiographic result by most CTO interventionists. For all procedures, we tried antegrade wiring first for all cases even in the presence of an unfavorable anatomy. The timing of guidewire escalation/de-escalation and switching to a parallel-wire technique was determined by each operator. When the antegrade intraplaque guidewire tracking failed and then the retrograde procedures were attempted, guidewires with softer tip load (mainly ≤1 g) were preferred for direct crossing or serving as the landmark for antegrade guidewire kissing. When both the aforementioned antegrade and retrograde wiring-based techniques failed to cross the occluded segment, reverse controlled antegrade and retrograde tracking or knuckle wire methods were used for rescue. However, both methods, even with successful recanalization, were not considered successful intraplaque tracking to minimize the potential confounding of the current study. If any of “must preserved” side branches ≥1.5 mm was lost during the procedure even with successful guidewire crossing, we always attempted to restore the antegrade flow to fulfil our principle. There were no “dissection and reentry” devices used in the study, and intravascular imaging was recommended but not mandatory. Moreover, restoration of thrombolysis in MI grade 3 anterograde flow, postprocedural stenosis of <30%, and the absence of in-hospital major adverse cardiac and/or cerebrovascular events, including cardiac death, Q-wave MI, stroke, or any repeat target lesion revascularization, were fundamental to the definition of procedural success. Detailed time intervals of guidewire crossing and the total procedure were recorded.
Statistical analyses
Statistical analyses were performed using the R 4.3.2 software (R Foundation for Statistical Computing, Vienna, Austria). In statistical testing, a 2-sided p value ≤ 0.05 was considered statistically significant. The distributional properties of continuous variables are expressed as mean ± standard deviation (SD) and categorical variables are expressed as frequencies and percentages. The p-values of statistical tests listed in the last column were calculated using the Wilcoxon rank-sum test for continuous variables and the Chi-square test for categorical variables. Based on the original J-CTO score study for de novo CTO lesions, the chance of guidewire crossing time ≥30 min was considered to be >50% if the score was ≥2. Therefore, we arbitrarily take the cut-off time of 30 min suggesting a prolonged time for successful guidewire crossing. Among the 470 patients with successful recanalization using intraplaque tracking techniques, the comparisons of the guidewire crossing time and the percentage of guidewire crossing time ≥30 min between patients with de novo and in-stent CTOs across the J-CTO scores =0, 1, 2, and ≥3 were analyzed. Subsequently, multivariate logistic regression analysis was performed to calculate the odds ratio (OR) and 95% confidence interval (CI) to select a set of independent features associated with guidewire crossing time ≥30 min among the successfully recanalized CTO lesions with the J-CTO score ≥2. Furthermore, when considering the significantly different percentage of the retrograde approach used between the 2 groups and its potential effect on guidewire crossing time because of the recanalization principle of the study, we analyzed the effect of J-CTO score on guidewire crossing time in 442 patients with successful antegradeonly procedures (de novo CTO=370, in-stent CTO=72). The differences in the Kaplan–Meier curve of the time for guidewire crossing across each J-CTO score were initially compared using the log-rank test for patients with de novo and in-stent CTOs. Subsequently, the differences in the distributions of continuous and categorical variables across each J-CTO score were examined using the Kruskal-Wallis rank-sum test and Chi-square test as appropriate for the data type. Next, multivariate analysis was performed by fitting a Cox’ proportional hazards model for the time to guidewire crossing (in minutes) to estimate the adjusted hazard ratios of clinical variables and each J-CTO score relative to J-CTO score = 0 in patients with de novo and in-stent CTOs. Linear regression analysis of the guidewire crossing time (in minutes) was performed to estimate the adjusted effects of the contributing factors (including the 5 parameters for counting the total J-CTO score) in patients with de novo and in-stent CTOs. All the univariate significant and nonsignificant relevant covariates listed in Tables 1 and 2 were put on the variable list to be selected. The detailed statistical methods were described in the Appendix .
Table 1
Comparisons of clinical features between patients with de novo and in-stent CTO
|
All
( N = 508) |
de novo
(N = 434) |
In-stent
(N = 74) |
p-value | |
|---|---|---|---|---|
| Age (yrs) | 64.6 ± 11.6 | 63.8 ± 11.9 | 65.9 ± 9.1 | 0.146 |
| Male (%) | 446 (88%) | 382 (88%) | 64 (89%) | 0.693 |
| BMI (kg/m 2) | 26.2 ± 3.8 | 26.2 ± 3.8 | 26.0 ± 3.6 | 0.610 |
| Hypertension (%) | 388 (76%) | 332 (76%) | 56 (76%) | 0.878 |
| Diabetes (%) | 214 (42%) | 175 (40%) | 39 (53%) | 0.046 |
| Dyslipidemia (%) | 388 (76%) | 327 (75%) | 61 (82%) | 0.185 |
| Smoking (%) | 180 (35%) | 157 (36%) | 23 (31%) | 0.398 |
| Old MI (%) | 111 (22%) | 87 (20%) | 24 (32%) | 0.017 |
| CABG (%) | 39 (8%) | 25 (6%) | 14 (19%) | < 0.001 |
| CHF (%) | 128 (25%) | 101 (23%) | 27 (36%) | 0.015 |
| eGFR<60 ml/min/1.73m 2 (%) | 130 (26%) | 104 (23%) | 26 (32%) | 0.074 |
| Stroke (%) | 32 (6%) | 27 (6%) | 5 (7%) | 0.861 |
BMI = body mass index; CABG = coronary artery bypass graft; CHF = congestive heart failure; CTO = chronic total occlusion; eGFR = estimated glomerular filtration rate; MI = myocardial infarction.
Table 2
Comparisons of angiographic and procedural characteristics between patients with de novo and in-stent CTO with intraplaque guidewire tracking techniques
|
All
(N = 508) |
de novo
(N = 434) |
In-stent
(N = 74) |
p-value | |
|---|---|---|---|---|
| Multivessel dz. (N) | 458(90%) | 393(91%) | 65(88%) | 0.470 |
| Lesion Location (N) | . | |||
| LAD (N) | 187(37%) | 169(39%) | 18(24%) | 0.016 |
| LCX (N) | 98(19%) | 83(19%) | 15(20%) | 0.818 |
| RCA (N) | 217(43%) | 180(41%) | 37(50%) | 0.171 |
| LM (N) | 2(0.4%) | 2(0.5%) | 0 | 0.559 |
| SVG (N) | 4(0.8%) | 0 | 4(5%) | < 0.001 |
| All transradial (N) | 374(74%) | 315(72%) | 59(80%) | 0.174 |
| All transfemoral (N) | 82(16%) | 68(16%) | 14(19%) | 0.588 |
| Radial+Femoral (N) | 52(10%) | 51(12%) | 1(1%) | 0.006 |
| J-CTO score | 2.3 ± 1.4 | 2.4 ± 1.4 | 1.9 ± 1.2 | 0.005 |
| Blunt stump (N) | 262(52%) | 242(56%) | 20(27%) | < 0.001 |
| Occlusion ≧20mm (N) | 282(56%) | 227(52%) | 55(74%) | < 0.001 |
| Calcification (N) | 278(55%) | 251(58%) | 27(35%) | < 0.001 |
| Bending >45∘(N) | 296(58%) | 258(59%) | 38(51%) | 0.192 |
| Retry case (N) | 70(14%) | 66(15%) | 4(5%) | 0.024 |
| Intravascular Imaging (N) | 227(45%) | 206(47%) | 21(27%) | 0.002 |
| IVUS (N) | 215(42%) | 197(45%) | 18(24%) | 0.001 |
| OCT (N) | 12(2%) | 9(2%) | 3(4%) | 0.379 |
| Multivessel PCI (N) | 212(42%) | 188(43%) | 24(32%) | 0.080 |
| Retrograde approach (N) | 41(8%) | 40(9%) | 1(1%) | 0.022 |
| Parallel wire (N) | 59(12%) | 59(14%) | 0 | 0.001 |
| Antegrade GW≧3 (N) | 173(34%) | 158(36%) | 15(20%) | 0.007 |
| RA (N) | 18(4%) | 17(4%) | 1(%) | 0.271 |
| Contrast volume (ml) | 171±82 | 179±85 | 131±49 | < 0.001 |
| Procedure time (min) | 81±54 | 84±56 | 65±43 | 0.004 |
| Successful intraplaque tracking (N) | 470 (93%) | 397(91%) | 73(99%) | 0.030 |
| RAK (Gy) | 5.9 ± 4.7 | 6.1 ± 4.8 | 4.8 ± 4.2 | 0.041 |
| DAP (mGym 2) | 37.7 ± 29.9 | 38.9 ± 30.4 | 31.0 ± 25.6 | 0.053 |
| Fluoroscopy time (min) | 58±34 | 60±35 | 46±29 | 0.003 |
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