BACKGROUND: The optimal endovascular treatment (EVT) for chronic total occlusion (CTO) lesions in patients with peripheral artery disease (PAD) has remained unestablished. We encountered a patient with PAD in whom CTO was successfully treated using a novel technique that involved intravascular ultrasound (IVUS) and angled guiding catheter: IVUS Preceding with Angled guiDing catheter (I-PAD) technique.
METHODS: A 74-year-old male presented with intermittent claudication attributed to CTO of the right external iliac artery. EVT was performed via the right common femoral artery. We retrogradely advanced the I-PAD system (i.e. partially extending the IVUS transducer portion from the tip of the angled guiding catheter) in the CTO lesion under the real-time guidance of IVUS imaging. We successfully traversed the CTO lesion without the use of a guidewire in approximately three minutes. The procedure concluded successfully without any procedure-related complications, following optimal stenting.
CONCLUSIONS: The I-PAD might be an effective technique to accurately, quickly, and safely pass through CTO lesions.

UNASSIGNED: This study aims to investigate the effects of coronary collateral circulation (CCC) on the prognosis of chronic total occlusion (CTO) patients with or without metabolic syndrome (MetS).
UNASSIGNED: The study included 342 CTO patients who underwent successful percutaneous coronary intervention at the People\'s Hospital of Liaoning Province between 1 February 2021 and 30 September 2023. The Rentrop score was used to assess the status of CCC. The outcome was major adverse cardiovascular and cerebrovascular events (MACCEs), defined as a composite of all-cause mortality, cardiac death, non-fatal myocardial infarction (MI), target vessel revascularization (TVR), and non-fatal stroke. Univariate and multivariate logistic analyses were used to investigate the association of CCC, MetS, and MACCEs with odds ratios (ORs) and 95% confidence intervals (CIs). The effect of CCC was further investigated in different MetS, diabetes mellitus (DM), and Syntax score groups.
UNASSIGNED: MACCEs were more common in patients with poor CCC compared to those with good CCC (38.74% vs. 16.56%). Statistical differences were found in MACCEs (OR = 3.33, 95% CI: 1.93-5.72), MI (OR = 3.11, 95% CI: 1.73-5.58), TVR (OR = 3.06, 95% CI: 1.70-5.53), and stent thrombosis (OR = 6.14, 95% CI: 2.76-13.65) between the good and poor CCC groups. Poor CCC patients with MetS had a higher incidence of MACCEs (OR = 4.21, 95% CI: 2.05-8.65), non-fatal MI (OR = 4.44, 95% CI: 2.01-9.83), TVR (OR = 3.28, 95% CI: 1.51-7.11), and stent thrombosis (OR = 10.80, 95% CI: 3.11-37.54). Similar findings were also observed in CTO patients with DM and a Syntax score ≥23.
UNASSIGNED: Poor CCC could increase the risk of MACCEs in CTO patients, particularly those with MetS, DM, and a Syntax score ≥23. Further prospective, multicenter studies are needed to validate our findings and to explore potential therapeutic interventions.

BACKGROUND: There is limited data on predicting successful chronic total occlusion crossing using primary antegrade wiring (AW).
OBJECTIVE: The aim of this study was to develop and validate a machine learning (ML) prognostic model for successful chronic total occlusion crossing using primary AW.
METHODS: We used data from 12,136 primary AW cases performed between 2012 and 2023 at 48 centers in the PROGRESS CTO registry (Prospective Global Registry for the Study of Chronic Total Occlusion Intervention; NCT02061436) to develop 5 ML models. Hyperparameter tuning was performed for the model with the best performance, and the SHAP (SHapley Additive exPlanations) explainer was implemented to estimate feature importance.
RESULTS: Primary AW was successful in 6,965 cases (57.4%). Extreme gradient boosting was the best performing ML model with an average area under the receiver-operating characteristic curve of 0.775 (± 0.010). After hyperparameter tuning, the average area under the receiver-operating characteristic curve of the extreme gradient boosting model was 0.782 in the training set and 0.780 in the testing set. Among the factors examined, occlusion length had the most significant impact on predicting successful primary AW crossing followed by blunt/no stump, presence of interventional collaterals, vessel diameter, and proximal cap ambiguity. In contrast, aorto-ostial lesion location had the least impact on the outcome. A web-based application for predicting successful primary AW wiring crossing is available online (PROGRESS-CTO website) (https://www.progresscto.org/predict-aw-success).
CONCLUSIONS: We developed an ML model with 14 features and high predictive capacity for successful primary AW in chronic total occlusion percutaneous coronary intervention.

BACKGROUND: The success rate of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) is lower and the risk for complications higher compared with other non-CTO PCI. Although interventionalists focus on intimal plaque characteristics, the coronary media is an important (especially for techniques involving antegrade dissection and re-entry) but poorly understood structure in CTO PCI.
OBJECTIVE: The aim of the present study was to investigate coronary medial wall thinning in CTO lesions and determine how this thinning might affect CTO PCI.
METHODS: A total of 2,586 sections were investigated, from arteries with evidence of CTO from 54 subjects (n = 1,383 sections) and arteries without evidence of CTO from 54 subjects with non-coronary-related deaths (n = 1,203 sections) after matching for age, gender, body weight, and body height.
RESULTS: The medial thickness in subjects with CTO was lower than that in those with non-coronary-related death (P < 0.001). In subjects with CTO, CTO lesions had thinner medial walls compared with those with lower luminal narrowing (P < 0.001). At the CTO distal segments, the 6- to 12-mm distal segment from the distal end of the CTO had significantly less luminal narrowing (P < 0.001), and similar medial thickness, compared with the distal end of the CTO. Immunohistochemical analysis revealed that short-duration CTO had more cleaved caspase-3-positive cells in media and had significantly more CD3+, CD4+, CD8+, and CD4+CD28null T cells compared with long-duration CTO.
CONCLUSIONS: CTO lesions demonstrated coronary medial thinning compared with non-CTO lesions. Further investigation of the cause-and-effect relationship among inflammation, apoptosis, and coronary medial wall thinning is warranted in future mechanistic studies.

Endovascular treatment is an acceptable option for patients with aortoiliac occlusive disease. However, bilateral passage of guidewires through the aortoiliac occlusion can be a challenging step in achieving successful revascularization. The aim of this article is to present a novel strategy for successfully passing bilateral guidewires through long aortoiliac occlusive lesions. After one guidewire is passed through the aortic and iliac lesions via one side of the femoral artery, the other guidewire is passed using the up-and-over technique and pulled out from the ipsilateral side of the body. This contralateral guidewire is then inserted into the ipsilateral angiographic catheter along with the ipsilateral guidewire. Subsequently, the angiographic catheter is removed in a manner similar to a peel-away sheath. Eventually, bilateral guidewires can be passed through the lesion via a single aortic tract.

Chronic total occlusions (CTOs) are frequent in patients with previous coronary artery bypass graft (CABG) surgery. Percutaneous coronary intervention (PCI) is the usual revascularization strategy. Whether or not the presence of a graft on a CTO vessel and post-PCI graft patency impacts outcomes after CTO-PCI is unknown. We sought to evaluate the impact of post-PCI graft patency on the durability of CTO-PCI. In total, 259 patients with previous CABG who underwent CTO-PCI in 12 international centers in 2019 to 2023 were categorized into \"grafted\" and \"ungrafted\" groups based on the presence of graft on a CTO vessel. The grafted group was subdivided into \"graft-occluded\" and \"graft-patent\" groups, depending on graft patency. The primary end points were (1) technical success rate, (2) target vessel failure, and (3) CTO failure rates at 1 year. CTO failure was defined as target vessel revascularization and/or significant in-stent restenosis. A total of 199 patients (77%) were in the grafted group. Grafted CTOs showed higher complexity and lower technical success rates (70% vs 80%, p = 0.004) than nongrafted CTOs. Of the grafted CTOs, 140 (70%) were in the grafted-occluded group and 59 (30%) were in the grafted-patent group. The technical success was lower in the former group (65% vs 81%, p = 0.022). An occluded graft was an independent predictor of technical failure (odds ratio 2.04, 95% confidence interval 1.03 to 4.76, p = 0.049) and persistent post-PCI graft patency was a strong independent predictor of CTO failure at 1 year (hazard ratio 5.6, 95% confidence interval 1.2 to 27.5, log-rank p = 0.033). In conclusion, in patients with previous CABG who underwent CTO-PCI, post-PCI graft patency was a significant predictor of CTO failure.

Although outcomes have improved with new-generation drug-eluting stents, few reports have analyzed the risk factors associated with chronic outcomes of chronic total occlusion (CTO)-percutaneous coronary intervention (PCI). This study aimed to investigate the independent risk factors for target lesion revascularization (TLR) and major adverse cardiac and cerebrovascular events (MACCEs) after CTO-PCI using Japanese multicenter data. A total of 3,666 patients, who underwent CTO-PCI and completed a 1-year follow-up, registered at the Japanese CTO-PCI Expert Registry from 2014 to 2019, were examined. The primary outcome was defined as TLR, and the secondary outcome was MACCEs at the 1-year follow-up. TLRs and MACCEs occurred in 175 (4.8%) and 524 (14.3%) patients, respectively. Multivariate logistic regression analysis demonstrated that in-stent occlusion (ISO) (odds ratio [OR] 2.604, 95% confidence interval [CI] 1.695 to 4.001), hemodialysis (OR 1.784, 95% CI 1.062 to 2.997), diabetes mellitus with insulin use (OR 1.741, 95% CI 1.060 to 2.861), moderate-to-severe calcification (OR 1.726, 95% CI 1.197 to 2.487), and the right coronary artery as the target vessel (OR 1.468, 95% CI 1.018 to 2.117) were significantly associated with TLR. Hemodialysis (OR 2.214, 95% CI 1.574 to 3.113), ISO (OR 1.499, 95% CI 1.127 to 1.993), arteriosclerosis obliterans (OR 1.414, 95% CI 1.074 to 1.863), and multivessel disease (OR 1.356, 95% CI 1.117 to 1.647) were significantly associated with MACCEs. One-year outcomes of new-generation drug-eluting stents for CTO-PCI were favorable, and ISO as a lesion factor and hemodialysis as a patient factor were strongly associated with TLR and MACCEs, respectively.

Antegrade wiring is the dominant method used in chronic total occlusion percutaneous coronary intervention (CTO PCI). However, distal cap puncture for distal true lumen wiring remains a significant barrier toward success. Three-dimensional (3D) fluoroscopic wiring can improve the speed, safety, and success of distal cap wiring. In this article, we provide 10 tips for every CTO interventionist to use when performing 3D wiring in distal true lumen wiring.

Safety is of critical importance to chronic total occlusion (CTO) percutaneous coronary intervention (PCI). This global consensus statement provides guidance on how to optimise the safety of CTO) PCI, addressing the following 12 areas: 1. Set-up for safe CTO PCI; 2. Guide catheter--associated vessel injuries; 3. Hydraulic dissection, extraplaque haematoma expansion, and aortic dissections; 4. Haemodynamic collapse during CTO PCI; 5. Side branch occlusion; 6. Perforations; 7. Equipment entrapment; 8. Vascular access considerations; 9. Contrast-induced acute kidney injury; 10. Radiation injury; 11 When to stop; and, 12. Proctorship. This statement complements the global CTO crossing algorithm; by advising how to prevent and deal with complications, this statement aims to facilitate clinical practice, research, and education relating to CTO PCI.

OBJECTIVE: To investigate whether Dual-Energy Computed Tomography (DECT) could be useful in the lesion characterization and endovascular treatment planning of symptomatic patients with peripheral arterial disease (PAD) due to Chronic Total Occlusions (CTO).
METHODS: Between 2018 and 2022, 60 symptomatic patients (52 male, age 71 years) with peripheral arterial CTO underwent DECT angiography before percutaneous endovascular treatment. Patients were classified, according to guidewire crossing difficulty into four categories, which were subsequently correlated with DECT values, including Dual Energy Index (DEI) and Effective Z (Zeff). DECT values were also corelated with crossing time. The crossing difficulty was further correlated with the Trans-Atlantic Inter-Society Consensus Document (TASC II) classification.
RESULTS: Technical success, defined as perceived antegrade true lumen or subintimal crossing, was achieved in 76.7 %. Among the cases, 20 were deemed easy, 14 moderate, 12 hard and 14 were failed attempts. Statistical analysis revealed a significant correlation between DEI, Zeff values, and the crossing difficulty categories (p < 0.001). Additionally, there was also a correlation between crossing time and DECT values. However, no significant correlation was recorded between difficulty categories and TASC II classification.
CONCLUSIONS: Pre-procedural DECT angiography provides valuable information for patient selection and planning of the revascularization strategy. Moreover, it is helpful in the selection of the appropriate PTA materials, based on the lesion characteristics. Further research should be invested in this important field, to determine the optimal treatment approach in patients suffering from PAD due to CTOs.