Coronary Chronic Total Occlusion Research Articles

Retrograde Coronary Chronic Total Occlusion Intervention (JR-CTO) Score: From the Japanese CTO-PCI Expert Registry.

Despite the effectiveness of the retrograde approach for chronic total occlusion (CTO) lesions, there are no standardized tools to predict the success of retrograde percutaneous coronary intervention (PCI). The objective of this study was to develop a prediction tool to identify CTO lesions that will achieve successful retrograde PCI. This study evaluated data from 2,374 patients who underwent primary retrograde CTO-PCI and were enrolled in the Japanese CTO-PCI Expert Registry between January 2016 and December 2022 (NCT01889459). All observations were randomly assigned to the derivation and validation cohorts at a 2:1 ratio. The prediction score for guidewire failure in retrograde CTO-PCI was determined by assigning 1 point for each factor and summing all accrued points. The JR-CTO score (moderate-severe calcification, tortuosity, Werner collateral connection grade≤1, and nonseptal collateral channel) demonstrated a C-statistic for guidewire failure of 0.72 (95%CI: 0.67-0.76) and 0.71 (95%CI: 0.64-0.77) in the derivation and validation cohorts, respectively. Patients with lower scores had higher guidewire and technical success rates and decreased guidewire crossing time and procedural time (P< 0.01). The JR-CTO (Japanese Retrograde Chronic Total Occlusion) score, a simple 4-item score that predicts successful guidewire crossing in patients undergoing retrograde CTO-PCI, has the potential to support clinical decision-making for the retrograde approach.

D-62 | Use of retrograde access via saphenous vein graft versus collaterals for recanalization of coronary chronic total occlusions: a meta-analysis

D-62 | Use of retrograde access via saphenous vein graft versus collaterals for recanalization of coronary chronic total occlusions: a meta-analysis

Impact of preventive substrate catheter ablation on implantable cardioverter-defibrillator interventions in patients with ischaemic cardiomyopathy and infarct-related coronary chronic total occlusion.

Primary prevention patients with ischemic cardiomyopathy and chronic total occlusion of an infarct-related coronary artery (IRA-CTO) are at a particularly high risk of implantable cardioverter-defibrillator (ICD) therapy occurrence. To evaluate the efficacy of preventive CTO-related substrate ablation strategy in ischaemic cardiomyopathy patients undergoing primary prevention ICD implantation. The PREVENTIVE VT study was a prospective, multicenter, randomized trial including ischaemic patients with ejection fraction ≤40%, no documented VAs, and evidence of scar related to the coronary CTO. Patients were randomly assigned 1:1 to a preventive substrate ablation before ICD implantation or standard therapy with ICD implantation only. The primary outcome was a composite of appropriate ICD therapy or unplanned hospitalization for VAs. Secondary outcomes included the primary outcome's components, the incidence of appropriate ICD therapies, cardiac hospitalization, electrical storm, and cardiovascular (CV) mortality. Sixty patients were included in the study. During the mean follow-up of 44.7± 20.7 months, the primary outcome occurred in 5 (16.7%) patients undergoing preventive substrate ablation and in 13 (43.3%) patients receiving only ICD (hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.12-0.94; P=0.037). Patients in the preventive ablation group also had fewer appropriate ICD therapies (P=0.039) and the electrical storms (Log rank: P=0.01). While preventive ablation also reduced cardiac hospitalizations (P=0.006), it had no significant impact on CV mortality (P=0.151). Preventive ablation of the coronary CTO-related substrate in patients undergoing primary ICD implantation is associated with the reduced risk of appropriate ICD therapy or unplanned hospitalization due to VAs.

[Correlation between insulin resistance and coronary collateral circulation in patients with chronic total coronary occlusion].

To explore the impact of diabetes on collateral circulation (CC) development in patients with chronic total coronary occlusion (CTO) and the underlying regulatory mechanism. This study was conducted among 87 patients with coronary heart disease (CHD), who had CTO in at least one vessel as confirmed by coronary angiography. Among them 42 patients were found to have a low CC level (Cohen-Rentrop grades 0-1) and 45 had a high CC level (grades 2-3). In the 39 patients with comorbid diabetes mellitus and 48 non-diabetic patients, insulin resistance (IR) levels were compared between the subgroups with different CC levels. The steady-state mode evaluation method was employed for calculating the homeostatic model assessment for insulin resistance index (HOMA-IR) using a mathematical model. During the interventional procedures, collateral and peripheral blood samples were collected from 22 patients for comparison of the metabolites using non-targeted metabolomics analysis. NT-proBNP levels and LVEF differed significantly between the patients with different CC levels (P<0.05). In non-diabetic patients, HOMA-IR was higher in low CC level group than in high CC level groups. Compared with the non-diabetic patients, the diabetic patients showed 63 upregulated and 48 downregulated metabolites in the collateral blood and 23 upregulated and 14 downregulated metabolites in the peripheral blood. The differential metabolites in the collateral blood were involved in aromatic compound degradation, fatty acid biosynthesis, and steroid degradation pathways; those in the peripheral blood were related with pentose phosphate metabolism, bacterial chemotaxis, hexanoyl-CoA degradation, glycerophospholipid metabolism, and lysine degradation pathways. The non-diabetic patients with a low level of CC had significant insulin resistance. The degradation pathways of aromatic compounds, fatty acid biosynthesis, and steroid degradation are closely correlated with the development of CC.

Impact of a Chronic Total Coronary Occlusion on the Incidence of Appropriate Implantable Cardioverter-Defibrillator Shocks and Mortality: A Substudy of the Dutch Outcome in ICD Therapy (DO-IT)) Registry.

Chronic total coronary occlusions (CTO) substantially increase the risk for sudden cardiac death. Among patients with chronic ischemic heart disease at risk for sudden cardiac death, an implantable cardioverter defibrillator (ICD) is the favored therapy for primary prevention of sudden cardiac death. This study sought to investigate the impact of CTOs on the risk for appropriate ICD shocks and mortality within a nationwide prospective cohort. This is a subanalysis of the nationwide Dutch-Outcome in ICD Therapy (DO-IT) registry of primary prevention ICD recipients in The Netherlands between September 2014 and June 2016 (n=1442). We identified patients with chronic ischemic heart disease (n=663) and assessed available coronary angiograms for CTO presence (n=415). Patients with revascularized CTOs were excluded (n=79). The primary end point was the composite of all-cause mortality and appropriate ICD shocks. Clinical follow-up was conducted for at least 2 years. A total of 336 patients were included, with an average age of 67±9 years, and 20.5% was female (n=69). An unrevascularized CTO was identified in 110 patients (32.7%). During a median follow-up period of 27 months (interquartile range, 24-32), the primary end point occurred in 21.1% of patients with CTO (n=23) compared with 11.9% in patients without CTO (n=27; P=0.034). Corrected for baseline characteristics including left ventricular ejection fraction, and the presence of a CTO was an independent predictor for the primary end point (hazard ratio, 1.82 [95% CI, 1.03-3.22]; P=0.038). Within this nationwide prospective registry of primary prevention ICD recipients, the presence of an unrevascularized CTO was an independent predictor for the composite outcome of all-cause mortality and appropriate ICD shocks.

Radiomics-based discrimination of coronary chronic total occlusion and subtotal occlusion on coronary computed tomography angiography

ObjectivesDifferentiating chronic total occlusion (CTO) from subtotal occlusion (SO) is often difficult to make from coronary computed tomography angiography (CCTA). We developed a CCTA-based radiomics model to differentiate CTO and SO.MethodsA total of 66 patients with SO underwent CCTA before invasive angiography and were matched to 66 patients with CTO. Comprehensive imaging analysis was conducted for all lesioned vessels, involving the automatic identification of the lumen within the occluded segment and extraction of 1,904 radiomics features. Radiomics models were then constructed to assess the discriminative value of these features in distinguishing CTO from SO. External validation of the model was performed using data from another medical center.ResultsCompared to SO patients, CTO patients had more blunt stumps (internal: 53/66 (80.3%) vs. 39/66 (59.1%); external: 36/50 (72.0%) vs. 20/50 (40.0%), both p < 0.01), longer lesion length (internal: median length 15.4 mm[IQR: 10.4-22.3 mm] vs. 8.7 mm[IQR: 4.9-12.6 mm]; external:11.8 mm[IQR: 6.1-23.4 mm] vs. 6.2 mm[IQR: 3.5-9.1 mm]; both p < 0.001). Sixteen unique radiomics features were identified after the least absolute shrinkage and selection operator regression. When added to the combined model including imaging features, radiomics features provided increased value for distinguishing CTO from SO (AUC, internal: 0.772 vs. 0.846; p = 0.023; external: 0.718 vs. 0.781, p = 0.146).ConclusionsThe occluded segment vessels of CTO and SO have different radiomics signatures. The combined application of radiomics features and imaging features based on CCTA extraction can enhance diagnostic confidence.

Impact of sex on myocardial perfusion following percutaneous coronary intervention of chronic total coronary occlusions

ObjectivesWe sought to investigate the impact of sex on myocardial perfusion changes following chronic total coronary occlusion (CTO) percutaneous coronary intervention (PCI) as measured by [15O]H2O positron-emission tomography (PET) perfusion imaging. BackgroundCTO PCI has been associated with an increase in myocardial perfusion, yet females are less likely to undergo revascularization. As such, data on the impact of sex on myocardial perfusion following CTO PCI is scarce. MethodsA total of 212 patients were prospectively enrolled and underwent CTO PCI combined with [15O]H2O PET perfusion imaging prior to and 3 months after PCI. Hyperemic myocardial blood flow (hMBF, mL·min−1·g−1) and coronary flow reserve (CFR) allocated to the CTO territory were quantitatively assessed. ResultsThis study comprised 34 (16 %) females and 178 (84 %) males. HMBF at baseline did not differ between sexes. Females showed a higher increase in hMBF than males (Δ1.34 ± 0.67 vs. Δ1.06 ± 0.74, p = 0.044), whereas post-PCI hMBF was comparable (2.59 ± 0.85 in females vs. 2.28 ± 0.84 in males, p = 0.052). Female sex was independently associated with a higher increase in hMBF after correction for clinical covariates. CFR increase after revascularization was similar in females and males (Δ1.47 ± 0.99 vs. Δ1.30 ± 1.14, p = 0.711). ConclusionsThe present study demonstrates a greater recovery of stress perfusion in females compared to males as measured by serial [15O]H2O PET imaging. In addition, a comparable increase in CFR was found in females and males. These results emphasize the benefit of performing CTO PCI in both sexes. Clinical perspectiveWhat is new?•CTO PCI has been associated with an increase in myocardial perfusion, yet females are less likely to undergo revascularization.•We found a greater recovery of stress perfusion in females compared to males after CTO PCI as measured by serial [15O]H2O PET imaging, whereas coronary flow reserve was comparable between sexes.•The present study adds to the limited body of evidence on the impact of sex on myocardial perfusion following CTO PCI.What are the clinical implications?•Our findings suggest that recovery of myocardial perfusion following CTO PCI is achievable in both female and male patients.•These results underscore the need to adhere to current guidelines for optimal CTO management in both sexes.•Future studies with standardized preprocedural imaging are warranted to increase our understanding of the impact of sex on changes in myocardial perfusion following CTO PCI.

Coronary Chronic Total Occlusion Revascularization: When, Who and How?

Coronary chronic total occlusions (CTO) are an increasingly frequent entity in clinical practice and represent a challenging percutaneous coronary intervention (PCI) scenario. Despite data from randomized trials that have not yet demonstrated a clear benefit of CTO recanalization, the widespread of CTO-PCI has substantially increased. The improvement in operators' techniques, equipment, and training programs has led to an improvement in the success rate and safety of these procedures, which will represent an important field of future development of PCI. The present review will summarize clinical outcomes and technical and safety issues of CTO revascularization with the aim to guide clinical daily cath-lab practice.

Prognostic Nutritional Index is Associated with the Degree of Coronary Collateral Circulation in Stable Angina Patients with Chronic Total Occlusion.

Coronary collateral circulation (CCC) can effectively improve myocardial blood supply to the area of CTO (chronic total coronary occlusion) and can, thus, improve the prognosis of patients with stable coronary syndrome (SCS). The degree of inflammation and some inflammation markers were associated with the development of collaterals. To investigate whether prognostic nutritional index (PNI) has an association with the development of CCC in patients with SCS. A total of 400 SCS patients with the presence of CTO in at least one major epicardial coronary artery were included in this study. The patients were divided into two groups according to the Rentrop score. Scores of 0 to 1 were considered poor developed CCC, and scores of 2 to 3 were accepted as good developed CCC. Statistical significance was set as a p-value < 0.05 for all analyses. The mean age of the study cohort was 63±10 years; 273 (68.3%) were males. The poor-developed CCC group had a significantly lower PNI level compared with the good-developed CCC group (38.29±5.58 vs 41.23±3.85, p< 0.001). In the multivariate analysis, the PNI (odds ratio 0.870; 95% confidence interval 0.822-0.922; p< 0.001) was an independent predictor of poorly developed CCC. The PNI can be used as one of the independent predictors of CCC formation. It was positively associated with the development of coronary collaterals in SCS patients with CTO.

Value of different CTO scoring systems in predicting procedural success in coronary chronic total occlusion intervention in Egyptian patients

BackgroundChronic total occlusion (CTO) lesions in coronary arteries pose a significant challenge for coronary interventionists, often leading to referrals for coronary artery bypass graft surgery (CABG). Successful percutaneous coronary intervention (PCI) for CTOs requires accurate assessment of procedural potential. This study, comprising 100 Egyptian patients aged 37–81, compares the predictive efficacy of various CTO scoring systems in PCI success determination. Patients with CTO in at least one coronary artery, planned for elective PCI based on objective evidence of ischemia, were included. Experienced operators performed PCI, recording procedural variables, and assessing complications. Logistic regression analysis revealed an inverse linear relationship between success rates and score values across all systems.ResultsAlthough, the predictive capacity of the scores was similar, with slight differences. The Euro CTO (CASTLE) score10 exhibited superior predictive efficacy, followed by the CL score9, while PROGRESS8 and J-CTO7 scores showed lower significance. ORA CTO11 score demonstrated intermediate predictive ability, and PROGRESS score8 had the least predictive value.ConclusionThe CASTLE score10 proved most effective in predicting PCI success for CTO cases in Egyptian patients, with operators advised to choose scoring systems based on experience and case characteristics. Proper planning remains crucial for optimizing success rates in CTO PCI procedures, irrespective of the scoring system employed.

The Characteristics of Primary Retrograde Approach Selection for Native Coronary Chronic Occlusion With Short Occlusion Length from the Japanese CTO-PCI Expert Registry

Although the coronary chronic total occlusion (CTO) crossing algorithm has been published, the characteristics associated with the first strategy selection for short-length lesions <20 mm is still debatable. This study aimed to determine the characteristics associated with primary retrograde approach (PRA) for native CTO with short occlusion length in percutaneous coronary intervention (PCI). Between January 2014 and December 2021, we examined data on 4,088 lesions in the Japanese CTO-PCI Expert Registry with occlusion lengths <20 mm. Then, the characteristics for short-length CTO, which was performed by way of the PRA, were assessed. PRA was performed in 785 patients (19.2%). The guidewire success rate was 93.6%, and the technical success rate was 91.3%. Previous coronary artery bypass grafting, chronic kidney disease, and 6 lesion/anatomic characteristics (i.e., blunt stump, distal runoff <1 mm, CTO lesion tortuosity, reattempt procedures, ostial location, and the presence of collateral channel grade 2) were associated with PRA (p <0.05). Moreover, hemodialysis was an independent factor of unsuccessful anterograde guidewire crossing, along with distal runoff <1 mm, the existence of calcification, and CTO lesion tortuosity (all p <0.05). In clinical settings, these independent factors for PRA in short-length CTO can help in selecting the CTO-PCI strategy.

Outcomes following coronary chronic total occlusion revascularization with drug-coated balloons.

Despite the introduction of improved drug eluting stents (DES), the rate of repeat revascularization procedures following percutaneous coronary interventions (PCI) in coronary chronic total occlusions (CTO) remains high. By leaving vessels uncaged and limiting length of stented segments, drug-coated balloons (DCB) represent an appealing alternative to DES for CTO-PCI. Since data supporting the use of DCBs in CTO-PCI is scarce, we compared the outcomes of patients undergoing CTO-PCI involving DCBs vs DES only. From 2 prospective registries, outcomes of patients undergoing CTO-PCI involving DCBs and those undergoing PCI with DES only were compared. Outcomes included major adverse cardiac and cerebrovascular events (MACCE) and cardiovascular death (CV-death). Overall, 157 patients were studied; 112 (71%) underwent CTO-PCI involving DCBs and 45 (29%) were treated with DES only. Mean J-CTO score was 1.84 ± 0.7. Most CTO-lesions involved the right coronary artery, 88 (56%), and 26 (17%) cases were in-stent occlusions. In the DCB group, 46 (41%) lesions were treated with DCBs alone. Mean lengths of the stented segments in the DCB vs DES cohorts were 59 ± 28 mm vs 87 ± 37 mm (P less than .001), respectively. After 12 months, the MACCE rate was higher in the DES only vs DCB group (26% vs 11%, P=.03). Length of the stented segment was an independent predictor for MACCE (HR 1.15 [95% CI, 1.05-1.26] per 10-mm stent length). Revascularization of CTO lesions involving DCBs appears safe and potentially lowers MACCE rates compared to treatment with DES alone. Importantly, using DCBs for CTO treatment may reduce total stent length, which determines PCI outcomes.

Self-Apposing Stents in Coronary Chronic Total Occlusions: A Pilot Study

This pilot study assessed the 12-month angiographic and clinical outcomes of self-apposing (SA) stents in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Self-apposing (SA) stents may decrease incomplete strut apposition and stent strut coverage that are common after CTO PCI. We compared 20 patients who underwent CTO PCI using SA drug-eluting stents (DESs) with 20 matched control patients who underwent CTO PCI using balloon-expandable (BE)-DESs. All patients were followed up clinically for 12 months and had coronary angiography with optical coherence tomography at the end of the follow-up period. The primary end points were stent strut malapposition and strut coverage. The secondary end point was composite major adverse cardiovascular events (MACEs) at 12 months. Both groups had high prevalence of diabetes mellitus, and most of the treated lesions were complex, with 62% having a J-CTO score of ≥3. All CTO PCI techniques were allowed for recanalisation, and 75% of the procedures were guided by intravascular ultrasound. At 12 months, the SA-DES group had fewer malapposed struts (0% [interquartile range (IQR) 0%-0%] vs 4.5% [IQR 0%-20%]; p<0.001) and uncovered struts (0.08% [IQR 0%-1.6%] vs 8.2% [IQR 0%-16%]; p<0.001). However, they showed significantly higher rates of MACEs due to clinically-driven target lesion revascularisation (45% vs 15%; p=0.038). In this pilot study, compared with conventional BE-DESs, SA-DESs used in CTO PCI were associated with fewer malapposed and uncovered stent struts but also with significantly higher rates of in-stent restenosis and MACEs, mainly caused by clinically driven target lesion revascularisation.

Scoring system related to retrograde percutaneous coronary intervention for coronary chronic total occlusion

AbstractThe retrograde approach is a principal procedure used in coronary chronic total occlusion percutaneous coronary intervention. However, the retrograde approach presents more challenges compared with the antegrade approach, as it is associated with a lower rate of success and a higher risk of complications. An accurate pre‐procedural evaluation of the complexity of a lesion could aid in the planning of the procedure, in estimating the procedure's duration, or in determining whether the patient should be referred to another center specializing in CTO‐PCI, as well as in a more precise evaluation of the risk‐benefit ratio. In recent years, multiple scoring systems have been created to forecast the success and efficiency of the retrograde procedure. However, each scoring system was developed independently, and comparative studies were lacking. This article provides a review of these scoring systems, offers an overview of the current state of the retrograde approach, and aims to stimulate further discussion on this topic.

Coronary chronic total occlusion on coronary CT angiography: what radiologists should know?

Coronary chronic total occlusion (CTO) often occurs in patients with obstructive coronary artery disease, which remains one of the greatest challenges for interventional cardiologists. Coronary computed tomography angiography (CCTA) with its emerging post-processing techniques can provide a detailed assessment of CTO lesions before percutaneous coronary intervention (PCI), playing an important role in the clinical management of CTO PCI, from early diagnosis, pre-procedural outcome prediction, the crossing algorithm planning, intraprocedural guidance, and finally post-procedural assessment and follow-up. In addition, the feasibility of CT perfusion (CTP) in patients with CTO has been validated. Combined CCTA and CTP have the great potential to be the one-stop-shop imaging modality for assessing both anatomy and function of CTO lesions. This review aims to make radiologists understand the role of CCTA in the diagnosis and assessment of CTO lesions, thus assisting interventionalists in optimizing CTO PCI crossing strategies with the expertise of radiologists.Critical relevance statement The anatomical features of CTO on CCTA can reveal the complexity of CTO lesions and are associated with CTO PCI outcome, thus helping interventionalists optimize CTO PCI crossing strategies.Key points • CTO is the common lesion in invasive coronary angiography, and CTO PCI is technically difficult and its success rate is relatively low.• Length, collaterals, and attenuation-related signs can help distinguish CTO from subtotal occlusion.• The anatomical features of CTO lesions can help grade the difficulty of CTO PCI and predict procedural outcomes and long-term outcomes of CTO PCI.• The real-time fusion of CCTA with fluoroscopic angiography can be applied in highly complicated CTO lesions.• After CTO PCI, CCTA can help guide a second CTO PCI re-entry or followup stent patency.

Outcomes following coronary chronic total occlusion revascularization with drug-coated balloons.

Despite the introduction of improved drug eluting stents (DES), the rate of repeat revascularization procedures following percutaneous coronary interventions (PCI) in coronary chronic total occlusions (CTO) remains high. By leaving vessels uncaged and limiting length of stented segments, drug-coated balloons (DCB) represent an appealing alternative to DES for CTO-PCI. Since data supporting the use of DCBs in CTO-PCI is scarce, we compared the outcomes of patients undergoing CTO-PCI involving DCBs vs DES only. From 2 prospective registries, outcomes of patients undergoing CTO-PCI involving DCBs and those undergoing PCI with DES only were compared. Outcomes included major adverse cardiac and cerebrovascular events (MACCE) and cardiovascular death (CV-death). Overall, 157 patients were studied; 112 (71%) underwent CTO-PCI involving DCBs and 45 (29%) were treated with DES only. Mean J-CTO score was 1.84 ± 0.7. Most CTO-lesions involved the right coronary artery, 88 (56%), and 26 (17%) cases were in-stent occlusions. In the DCB group, 46 (41%) lesions were treated with DCBs alone. Mean lengths of the stented segments in the DCB vs DES cohorts were 59 ± 28 mm vs 87 ± 37 mm (P less than .001), respectively. After 12 months, the MACCE rate was higher in the DES only vs DCB group (26% vs 11%, P=.03). Length of the stented segment was an independent predictor for MACCE (HR 1.15 [95% CI, 1.05-1.26] per 10-mm stent length). Revascularization of CTO lesions involving DCBs appears safe and potentially lowers MACCE rates compared to treatment with DES alone. Importantly, using DCBs for CTO treatment may reduce total stent length, which determines PCI outcomes.

A non-interventional cardiologist's guide to coronary chronic total occlusions.

Coronary chronic total occlusions (CTO) are present in up to one-third of patients with coronary artery disease (CAD). It is thus essential for all clinical cardiologists to possess a basic awareness and understanding of CTOs, including optimal evaluation and management. While percutaneous coronary intervention (PCI) for CTO lesions has many similarities to non-CTO PCI, there are important considerations pertaining to pre-procedural evaluation, interventional techniques, procedural complications, and post-procedure management and follow-up unique to patients undergoing this highly specialized intervention. Distinct from other existing topical reviews, the current manuscript focuses on key knowledge relevant to non-interventional cardiologists.

Evaluation and management of patients with coronary chronic total occlusions considered for revascularisation. A clinical consensus statement of the European Association of Percutaneous Cardiovascular Interventions (EAPCI) of the ESC, the European Association of Cardiovascular Imaging (EACVI) of the ESC, and the ESC Working Group on Cardiovascular Surgery.

Chronic total occlusions (CTOs) of coronary arteries can be found in the context of chronic or acute coronary syndromes; sometimes they are an incidental finding in those apparently healthy individuals undergoing imaging for preoperative risk assessment. Recently, the invasive management of CTOs has made impressive progress due to sophisticated preinterventional assessment, including advanced non-invasive imaging, the availability of novel and dedicated tools for CTO percutaneous coronary intervention (PCI), and experienced interventionalists working in specialised centres. Thus, it is crucial that referring physicians who see patients with CTO be aware of recent developments and of the initial evaluation requirements for such patients. Besides a careful history and clinical examination, electrocardiograms, exercise tests, and non-invasive imaging modalities are important for selecting the patients most suitable for CTO PCI, while others may be referred to coronary artery bypass graft or optimal medical therapy only. While CTO PCI improves angina and reduces the use of antianginal drugs in patients with symptoms and proven ischaemia, hibernation and/or wall motion abnormalities at baseline or during stress, the effect of CTO PCI on major cardiovascular events is still controversial. This clinical consensus statement specifically focuses on referring physicians, providing a comprehensive algorithm for the preinterventional evaluation of patients with CTO and the current evidence for the clinical effectiveness of the procedure. The proposed care track has been developed by members and with the support of the European Association of Percutaneous Cardiovascular Interventions (EAPCI), the European Association of Cardiovascular Imaging (EACVI), and the European Society of Cardiology (ESC) Working Group on Cardiovascular Surgery.

The prognostic value of collateral circulation in coronary chronic total occlusion underwent percutaneous coronary intervention.

The prognostic value of coronary collateral circulation (CC) in patients undergoing chronic total occlusion (CTO) percutaneous coronary intervention (PCI) is underdetermined. The purpose of the study was to assess the prognostic value of current two CC grading systems and their association with long-term outcomes in patients with CTO underwent PCI. We consecutively enrolled patients with single-vessel CTO underwent PCI between January 2010 and December 2013. All patients were categorized into well-developed or poor-developed collaterals group according to angiographic Werner's CC (grade 2 vs. grade 0-1) or Rentrop (grade 3 vs. grade 0-2) grading system. The primary endpoint was 5-year cardiac death. Of 2452 enrolled patients, the overall technical success rate was 74.1%. Well-developed collaterals were present in 686 patients (28.0%) defined by Werner's CC grade 2, and in 1145 patients (46.7%) by Rentrop grade 3. According to Werner's CC grading system, patients with well-developed collaterals had a lower rate of 5-year cardiac death compared with those with poor-developed collaterals (1.6% vs. 3.3%, P = 0.02), those with suboptimal recanalization was associated with higher rate of 5-year cardiac death compared with optimal recanalization (4.7% vs. 0.8%, P = 0.01) and failure patients (4.7% vs. 1.6%, P = 0.12). However, the similar effect was not shown in Rentrop grading system. In patients with the single-vessel CTO underwent PCI, well-developed collaterals by Werner's CC definition were associated with lower rate of 5-year cardiac death. Werner's CC grading system had a greater prognostic value than Rentrop grading system in patients with CTO underwent PCI.

Circ-MBOAT2 Regulates Angiogenesis via the miR-495/NOTCH1 Axis and Associates with Myocardial Perfusion in Patients with Coronary Chronic Total Occlusion.

Revascularization of coronary chronic total occlusion (CTO) still remains controversial. The factors that impact collateral circulation and myocardial perfusion are of interest. Circular RNA (circRNA) has been shown to regulate the process of angiogenesis. However, the effects of circ-membrane-bound O-acyltransferase domain containing 2 (circ-MBOAT2) on angiogenesis in patients with CTO were unclear. In this study, we evaluated circulating circRNAs and miRNAs in patients with CTO and stable coronary artery disease using high-throughput sequencing. Another cohort of patients were selected to verify the expressions of circ-MBOAT2 and miR-495. The role and mechanism of circ-MBOAT2 in the process of angiogenesis were explored through in vitro and vivo studies. Finally, we came back to a clinical perspective and investigated whether circ-MBOAT2 and miR-495 were associated with the improvement of myocardial perfusion evaluated by single-photon emission computed tomography (SPECT). We found that the expression of circ-MBOAT2 was significantly up-regulated while miR-495 was significantly down-regulated in patients with CTO. The expression of circ-MBOAT2 was negatively correlated with miR-495 in patients with CTO. In an in vitro study, we found that circ-MBOAT2 promoted tube formation and cell migration via the miR-495/NOTCH1 axis in endothelial cells. In an in vivo study, we showed that the inhibition of miR-495 caused the increase in collateral formation in mice after hindlimb ischemia. In a human study, we showed the expressions of circ-MBOAT2 and miR-495 were associated with myocardial perfusion improvement after revascularization of CTO. In conclusion, circ-MBOAT2 regulates angiogenesis via the miR-495/NOTCH1 axis and associates with myocardial perfusion in patients with CTO. Our findings suggest that circ-MBOAT2 and miR-495 may be potential therapeutic targets and prognostic factors for patients with CTO.