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(1) Background: The probability of technical success in percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) represents essential information for specifying the priority of PCI for treatment selection in patients with CTO. However, the predictabilities of existing scores based on conventional regression analysis remain modest, leaving room for improvements in model discrimination. Recently, machine learning (ML) techniques have emerged as highly effective methods for prediction and decision-making in various disciplines. We therefore investigated the predictability of ML models for technical results of CTO-PCI and compared their performances to the results from existing scores, including J-CTO, CL, and CASTLE scores. (2) Methods: This analysis used data from the Japanese CTO-PCI expert registry, which enrolled 8760 consecutive patients undergoing CTO-PCI. The performance of prediction models was assessed using the area under the receiver operating curve (ROC-AUC). (3) Results: Technical success was achieved in 7990 procedures, accounting for an overall success rate of 91.2%. The best ML model, extreme gradient boosting (XGBoost), outperformed the conventional prediction scores with ROC-AUC (XGBoost 0.760 [95% confidence interval {CI}: 0.740–0.780] vs. J-CTO 0.697 [95%CI: 0.675–0.719], CL 0.662 [95%CI: 0.639–0.684], CASTLE 0.659 [95%CI: 0.636–0.681]; p < 0.005 for all). The XGBoost model demonstrated acceptable concordance between the observed and predicted probabilities of CTO-PCI failure. Calcification was the leading predictor. (4) Conclusions: ML techniques provide accurate, specific information regarding the likelihood of success in CTO-PCI, which would help select the best treatment for individual patients with CTO.

To evaluate the procedural results and in-hospital outcomes of percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) in patients with reduced left ventricular ejection fraction (LVEF).While the technical success of general CTO-PCI has improved, CTO-PCI patients with reduced LVEF remain at high-risk for adverse events.The data of 820 patients with LVEF ≤ 35% (Group 1), 1816 patients with LVEF = 35%-50% (Group 2), and 5503 patients with LVEF ≥ 50% (Group 3), registered in the Japanese CTO-PCI Expert Registry from January 2014 to December 2019, were retrospectively analyzed. The primary endpoint was in-hospital major adverse cardiac or cerebrovascular events (MACCEs), including death, myocardial infarction, stent thrombosis, stroke, and emergent revascularization. Secondary endpoints included procedural details, guidewire success, and technical success.There were no differences in guidewire and technical success rates between the groups. In-hospital MACCEs was significantly higher in Group 1 (Group 1 vs. Group 2 vs. Group 3: 3.4% vs. 1.7% vs. 1.5%, p = 0.001) and was especially driven by death (1.3% vs. 0.3% vs. 0.1%, p 0.001) and stroke (0.7% vs. 0.2% vs. 0.2%, p = 0.007). Multivariate analysis showed that LVEF ≤ 35% (odds ratio [OR]; 1.58, 95% confidence interval [CI]; 1.04-2.41, p = 0.03) and New York Heart Association (NYHA) class ≥ 3 (OR; 2.01, 95% CI; 1.03-3.93, p = 0.04) were predictors of in-hospital MACCEs.In-hospital MACCEs were significantly higher in patients with LVEF ≤ 35%. LVEF ≤;35% and NYHA class ≥ 3 were predictors of in-hospital MACCEs after CTO-PCI.

Aims Guidewire (GW) tracking in a collateral channel (CC) is an important step during retrograde chronic total occlusion (CTO) percutaneous coronary intervention (PCI). The aim of this study was to create a prediction score model for CC GW crossing success. Methods and results We analysed data on 886 CCs included in the Japanese CTO PCI Expert Registry during 2016. CCs were categorised as septal (n=610) and non-septal (n=276). CCs were randomly assigned to derivation and validation sets in a 2:1 ratio. The score was developed by multivariate analysis with angiographic findings. Small vessel, reverse bend, and continuous bends were independent predictors in the septal CC subset. Small vessel, reverse bend, and corkscrew were independent predictors in the non-septal CC subset. The extent of intervention was easy, intermediate, and difficult in 92.9%, 57.4%, and 16.7% in the septal CC subset and 91.7%, 54.3%, and 19.0% in the non-septal CC subset, respectively, in the validation set. The area under the receiver operating characteristic curve was >0.7 in the derivation and validation sets of both CC subsets. Conclusions The prediction score model can suggest grading of the difficulty of CC GW crossing based on angiographic findings for each type of CC.

Guidewire manipulation time is rarely used in chronic total occlusion (CTO) percutaneous coronary intervention (PCI) strategies.This study sought to develop an algorithm based on angiographic characteristics and guidewire manipulation time.This study assessed 5,843 patients undergoing CTO PCI between January 2014 and December 2017 and enrolled in the Japanese CTO-PCI expert registry and analyzed their CTO-PCI strategies, procedural outcomes, and guidewire manipulation time.Primary retrograde approach was performed on 1,562 patients. The average Japanese CTO score of primary antegrade approach and primary retrograde approach were 1.7 ± 1.1 and 2.3 ± 1.1, respectively (p 0.001). The overall guidewire and technical success rates were 92.8% and 90.6%, respectively. Median guidewire manipulation time of guidewire success and failure were 56 min (interquartile range [IQR]: 22 to 111 min) and 176 min (IQR: 130 to 229 min), respectively. Median successful guidewire crossing time of single wiring and parallel wiring in the antegrade alone were 23 min (IQR: 11 to 44 min) and 60 min (IQR: 36 to 97 min), and rescue retrograde approach and primary retrograde approach were 126 min (IQR: 87 to 174 min) and 107 min (IQR: 70 to 161 min), respectively (p 0.001). Significant predictors for antegrade guidewire failure in primary antegrade approach, which were reattempt, CTO length of ≥20 mm, and no stump, did not predict guidewire failure after collateral channel crossing in primary retrograde approach.Results from a large registry with information on guidewire manipulation time as well as CTO characteristics suggest a redefinition of the current strategy algorithms.

Objectives This report describes the registry and presents an initial analysis of outcomes for the different PCI approaches taken by the specialists. Background Strategies for percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) are complex. The Japanese Board of CTO Interventional Specialists has developed a prospective, nonrandomized registry of patients undergoing CTO-PCIs performed by 41 highly experienced Japanese specialists. Methods Over the study period of January 2014 to December 2015, the registry included 2,846 consecutive CTO-PCI cases undertaken in Japan. The authors compared clinical outcomes between the different PCI approaches, following the intention-to-treat principle. Results The overall technical success rate of the procedures was 89.9%. The specialists frequently chose a retrograde approach as the primary CTO-PCI strategy (in 27.8% of cases). The technical success rate of the primary antegrade approach was significantly better than that of the primary retrograde approach (91.0% vs. 87.3%; p Conclusions CTO-PCI performed by highly experienced specialists achieved a high technical success rate.

Objectives To examine the safety, efficacy, and efficiency of the PlasmaWireTM System to recanalize coronary chronic total occlusions (CTO) using controlled ablation inside the CTO. Background The PlasmaWireTM System is a new bipolar radiofrequency (RF) wire system utilizing plasma-mediated ablation to facilitate wire crossing in CTOs. Two independent PlasmaWireTM wires are used in tandem for channel creation by applying RF energy between the tips so as to localize the ablation. Methods Prospective, nonrandomized, single-arm, multicenter study in seven patients with CTOs indicated for percutaneous coronary intervention (PCI). Results In this study, both wires were antegradely delivered to the distal end of CTO for antegrade re-entry in two cases and bidirectionally (antegrade and retrograde) delivered to the CTO for retrograde re-entry in five cases. In all cases, channel creation was achieved within a few seconds and was confirmed on angiogram or intravascular ultrasound (IVUS) and CTO recanalization was successfully achieved without any major adverse cardiac and cerebrovascular events (MACCE) or other minor complications. The clinical follow-up showed no clinical event at 1 month. Conclusions The PlasmaWireTM System was shown to be safe and effective in obtaining CTO recanalization through a re-entry channel utilizing plasma-mediated ablation while reducing procedure time. The PlasmaWire™ System is a new bi-polar RF wire system utilizing plasma-mediated ablation for channel creation to facilitate CTO recanalization. This first-in-human study in which seven patients were enrolled was conducted to demonstrate the safety, efficacy, and efficiency of this system for CTO recanalization. Channels through the CTOs were successfully created within a few seconds by applying RF energy between the tips of two independent PlasmaWireTM wires and recanalization was achieved in all cases without any complication. The PlasmaWireTM System may safely facilitate CTO recanalization with less vessel injury and improve initial results of CTO PCI while reducing procedure time.

Background The percutaneous coronary intervention (PCI) strategy for chronic total occlusion (CTO) based on the guidewire manipulation time remains infrequent. Purpose We aimed to assess CTO-PCI strategy on the basis of guidewire manipulation time. Methods A total of 5843 patients undergoing CTO PCI between January 2014 and December 2017 and enrolled in the Japanese CTO-PCI expert registry were assessed. Their CTO-PCI strategies, procedural outcomes, and guidewire manipulation time were analysed. Results The primary retrograde approach was performed on 1562 patients (26.7%). The overall guidewire and technical success rates were 92.8% and 90.6%, respectively. Median guidewire manipulation time of guidewire success and failure were 56 (interquatile range [IQR]: 22 to 111) min and 176 (IQR: 130 to 229) min, respectively. The average Japanese CTO score of the primary antegrade approach with the antegrade alone, the primary antegrade approach with the retrograde approach, and the primary retrograde approach were 1.7±1.1, 2.1±1.2, and 2.3±1.1, respectively (p Conclusions Although successful guidewire crossing time of the primary antegrade approach with the antegrade alone is short, that of the primary retrograde approach can be shorter than that of the primary antegrade approach with the retrograde approach. Choosing an appropriate CTO-PCI strategy leads to shortening of successful guidewire crossing time.

Surgeons currently use two different wire-based approaches to recanalize coronary chronic total occlusion (CTO): antegrade and retrograde. It has been demonstrated that the retrograde approach has improved the procedural success rate, but it remains unclear whether the retrograde approach is better than the antegrade approach for the long term. In this study, we enrolled a total of 187 patients with a diagnosis of CTOs. We evaluated the baseline characteristics of these patients and performed percutaneous coronary intervention to treat their problems by using either antegrade or retrograde approaches and different techniques in both groups. In the antegrade approach, we used three techniques: single wire, parallel wire, and side branch. The techniques in retrograde included kissing wire, controlled antegrade and retrograde subintimal tracking (CART), and reverse CART. We found that the antegrade and retrograde groups had similar baseline characteristics, with a few minor differences. Most importantly, we found that within 1 yr of the recanalizing procedure, the restenosis rate and major adverse cardiac event rate of the retrograde group were significantly higher compared to the antegrade group. We conclude that the retrograde approach may not be as beneficial as the antegrade approach for long-term clinical outcomes.

Coronary chronic total occlusions (CTOs) are commonly encountered in patients undergoing coronary angiography. Several observational studies have demonstrated that successful CTO revascularization is associated with better cardiovascular outcomes and enhanced quality of life (QOL). However, in the absence of randomized trials, its prognostic benefit for patients remains debated. Over the past decade, the interest of the interventional community in CTO percutaneous coronary intervention (PCI) has exponentially grown due to important developments in dedicated equipment and techniques, resulting in high success and low complication rates. Both European and American guidelines have assigned a class IIa (level of evidence B) recommendation for CTO PCI. In the current review, we focus on the impact of CTO revascularization on clinical outcomes and QOL and on appropriate patient selection, and we provide a critical assessment of the current guidelines and recommendations on CTO PCI.

We investigated the horizontal distribution of Nemopilema nomurai medusae using a midwater trawl in the southwestern Sea of Japan from September to October of each year from 2006 to 2012. Numerous medusae of this species found in 2006, 2007, and 2009 were mainly distributed far (>40 km) from the mainland of Japan in the western part of the survey area, but were distributed in the stations closest (

We compiled a long-term record of monthly mean sea surface currents in the Japan Sea from satellite altimetry and satellite-tracked drifter data. The record covers the entire Japan Sea for the period from May 1995 through January 2009. Using these data, we examined the path of the Tsushima Warm Current in the southwestern part of the Japan Sea. The mean sea surface current field revealed a “triple-branch” pattern. The first branch through the eastern channel of the Tsushima Strait flows along the coast of Japan with a mean current velocity of 20 cm s −1 . The second branch flows along the continental shelf edge at around the 200-m isobath with a mean current velocity of 12 cm s −1 . The third branch flows along the east coast of the Korean peninsula with a mean current velocity of 25 cm s −1 . We investigated seasonal variation in the path of each branch. The first branch flowing along the Japanese coast throughout the year is highly stable. The second branch is stable throughout the year except in November. The third branch flowing along the east coast of Korea is highly stable until 38°N. Downstream of the third branch around 38°N, the current bifurcates into northeastward and southeastward currents. The northeastward current exhibits stable flow from June to February except in January. This current joins an eastward current originating around 39°N, 128.5°E. The southeastward current flows stably in June, September, and December. There were two current paths east of 131°E over the continental shelf off the San’in coast of Japan. The nearshore current flows along the Japanese coast with a mean current velocity of 23 cm s −1 , and the offshore current flows around the continental shelf area with a mean current velocity of 19 cm s −1 . These two currents are highly stable throughout the year. A current flows to the west of Oki Island to around 38.5°N and is highly stable in all months except March to July. These results provide a schematic view of the paths of the Tsushima Warm Current in the southwestern part of the Japan Sea.

This report describes the registry and presents an initial analysis of outcomes for the different PCI approaches taken by the specialists.Strategies for percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) are complex. The Japanese Board of CTO Interventional Specialists has developed a prospective, nonrandomized registry of patients undergoing CTO-PCIs performed by 41 highly experienced Japanese specialists.Over the study period of January 2014 to December 2015, the registry included 2,846 consecutive CTO-PCI cases undertaken in Japan. The authors compared clinical outcomes between the different PCI approaches, following the intention-to-treat principle.The overall technical success rate of the procedures was 89.9%. The specialists frequently chose a retrograde approach as the primary CTO-PCI strategy (in 27.8% of cases). The technical success rate of the primary antegrade approach was significantly better than that of the primary retrograde approach (91.0% vs. 87.3%; p 0.0001). The technical success rate decreased to 78.0% with the rescue retrograde approach. Parallel guidewire crossing and intravascular ultrasound-guided wire crossing were performed after guidewire escalation during antegrade CTO-PCI with a high technical success rate (75.0% to 88.9%). Severe lesion calcification was a strong predictor of failed CTO-PCI.CTO-PCI performed by highly experienced specialists achieved a high technical success rate.

Background Controlled antegrade and retrograde subintimal tracking (CART) or reverse CART techniques is the final step for percutaneous revascularization of coronary chronic total occlusion (CTO), but it still represents technical challenges and risk in interventional procedures. Objectives Our purpose was to utilize intravascular ultrasound (IVUS)-guided reverse CART approach for percutaneous revascularization of CTO in our heart center, focusing on its safety, efficacy, and latest technical developments. Methods From November 2006 to November 2012, 49 patients with CTO failed to antegrade and/or retrograde percutaneous revascularization of CTO from true lumen to true lumen were enrolled in and underwent IVUS guided reverse CART approach. Results The mean J-CTO score of cases was 2.5. IVUS guidance was successfully implemented in 95.9%; IVUS identified that 61.7% of retrograde wires were located at intimal space, and 59.5% of antegrade wires were located at subintimal space. A Corsair channel dilator was used in 77.6% of cases. The success rates of technique and procedure were 95.9% and 93.9%, respectively; the technical minor complications were observed in 10.2% of cases, without significant clinic outcomes; 2.0% of cases occurred with a major adverse cardiac event of non-ST-elevation myocardial infarction; and no case occurred with target vessel revascularization or death. The mean length of stent implanted in a single CTO vessel was 51.3 mm. No patient appeared with radiation dermatitis and contrast-induced rise of creatinine. Conclusions IVUS guided reverse CART approach is effective and safe for percutaneous revascularization of complex CTO, with a high success and a low complication rate. It is feasible to develop this approach for percutaneous revascularization of complex CTO. However, suitable case selection and lately device handling by experienced operators are the crucial points of success. (J Interven Cardiol 2013;26:434-443)

Recently, subintimal angioplasty has been introduced as a bailout strategy to improve the success rate of PCI for vessels with CTO. However, the long-term outcome of subintimal angioplasty has not been determined, and a limitation of subintimal angioplasty is the uncertainty in making the re-entry point. We report two cases, where occlusive in-stent restenosis occurred in a stent implanted in the subintimal space of the RCA that had CTO. These two cases were successfully treated with bypass restenting across the struts of an occluded subintimal stent using a retrograde approach. A retrograde wire crossed the occluded segment through the lumen along the outside of the stent and reentered the inside of the stent across the stent struts. The reverse CART technique followed by multiple restenting across the stent struts restored antegrade flow. Follow-up angiography demonstrated the patency of the RCA.

Objectives The aim of this study was to evaluate the relationship between cholesterol metabolism and coronary plaque vulnerability. Background Cholesterol homeostasis, defined as the balance between absorption and synthesis, influences the progression of coronary atherosclerosis. Methods Consecutive stable angina pectoris patients (N = 80) not receiving any lipid-lowering therapy were divided into 2 groups based on the presence of in vivo thin cap fibroatheroma (TCFA) in de novo target vessels assessed by the combined use of virtual histology intravascular ultrasound and optical coherence tomography. Results Patients with in vivo TCFA (n = 42) showed a higher campesterol-to-lathosterol ratio (3.36 [interquartile range, 2.10 to 4.26] vs. 1.50 [1.20 to 2.50], p Conclusions Enhanced absorption and reduced synthesis of cholesterol may be related to coronary plaque vulnerability.

Objective We evaluated, using quantitative coronary angiography, the natural history of change that occurred in target lesions after successful sirolimus-eluting stent (SES) implantation. Background Percutaneous coronary intervention with drug-eluting stents (DES) has significantly reduced the rate of repeated target lesion revascularization. However, early studies have raised concerns regarding the “late catch-up” phenomenon of DES. Methods Between June 2004 and March 2007, consecutive 217 patients with 306 lesions without restenosis at early angiographic follow-up underwent late angiographic follow-up (early follow-up: 11.2 ± 2.1 months and late follow-up: 29.4 ± 5.2 months). Predictors of late catch-up were identified with univariate and multivariate regression analyses. Results Although reference vessel diameter did not significantly change during follow-up [3.15 mm (interquartile range (IQR): 2.81–3.49 mm), 3.12 mm (IQR: 2.79–3.47 mm), and 3.08 mm (IQR: 2.76–3.46 mm) at postprocedure, and early and late angiographic follow-up, respectively; P = 0.2653], late loss (LL) significantly increased during follow-up [0.05 mm (IQR: 0.00–0.13 mm) and 0.08 mm (IQR: 0.01–0.19 mm) at early and late follow-up, respectively; P < 0.0001]. Univariate analysis showed previous intervention, adjunctive use of cutting balloon, lesion length, and progression of MLD, LL, %DS at early follow-up as predictors of late catch-up. Multivariate regression analysis identified %DS at early follow-up as a predictor of late catch-up (OR 1.076, CI 1.039–1.114, P < 0.0001). Conclusion Significant and continuous progression of neointima after SES implantation was observed in the present study. Larger LL may be a sign of late catch-up phenomenon. © 2012 Wiley Periodicals, Inc.

Background: Retrograde approach increases the success rate for percutaneous recanalization of complex chronic total occlusion (CTO) of coronary arteries. Objectives: The purpose of this study was to describe our initial experience of retrograde percutaneous coronary intervention for CTO program, focusing on its safety and feasibility, and long-term clinical follow-up. Methods: The study was a single center retrospective registry which included a total of 40 patients, of 590 CTO treated patients (6.7%), between January 2008 and October 2011, who underwent retrograde approach for CTO recanalization. Results: Mean occlusion duration was 37.8 ± 40.3 months. Overall success recanalization rate was 87.5% (35/40). Septal collaterals were used to access the occlusion in all cases (100%). Retrograde guidewire crossing of collateral channels was successful in 36/40 (90.0%) patients with success rate of CTO recanalization in these patients of 97.2%. Retrograde approach as the primary strategy was applied in 23/40 (57.5%) patients, retrograde approach immediately after antegrade failure attempt was performed in 8/40 (20.0%) patients, and retrograde approach as elective procedure, after previously failed antegrade attempt, was performed in 9/40 (22.5%) patients. The success rate of these strategies was: 87.0% (20/23 patients) for primary, 87.5% (7/8 patients) for retrograde immediately after antegrade failure, and 88.9% (8/9 patients) for retrograde after previous failed antegrade attempt, respectively. Total in-hospital major adverse cardiac events (MACE) rate was 5.0% (2 non-Q-wave myocardial infarctions). The MACE free survival at median follow-up of 20 months was 89% (95% CI: 78–100%). Conclusions: This study has demonstrated that adequate training and international proctorship for this complex and demanding technique is a necessity and prerequisite to achieve high overall success rates, with acceptable complication rates and excellent long-term survival rate. (J Interven Cardiol 2012;25:540–548).

Conflicting data have been reported about the association between plaque composition and remodelling index (RI). The aim of this study is to evaluate the relationship between plaque morphology obtained by optical coherence tomography (OCT) and arterial remodelling.OCT and intravascular ultrasound imaging pull back was performed at corresponding sites on 94 lesions in 47 patients. OCT plaque characteristics for lipid content, fibrous cap thickness, thin-cap fibroatheroma (TCFA), plaque rupture, thrombus, calcification and erosion were derived using validated criteria. Compared with intermediate/negative remodelling (RI1.0), positive remodelling (RI1.0) was associated with presence of higher lipid pool (2.86 ± 0.42 vs. 2.20 ± 0.78; p0.001), thin fibrous cap (47.86 ± 25.43 μm vs. 74.41 ± 32.41 μm; p0.001), TCFA3mm (82.1% vs. 22.7%; p0.0001), plaque rupture and thrombus (42.8% vs. 19.7%; p = 0.024), and higher plaque burden (73.70 vs. 70.70; p = 0.048). No difference was observed in the presence of calcification and plaque erosions.Coronary lesions with positive remodelling show higher incidences of vulnerable plaque and plaque rupture across the lesion length. This potentially explains the correlation between unstable coronary syndromes and positive remodelling.

Background— Frequency-domain optical coherence tomography (FD-OCT) is a novel, high resolution intravascular imaging modality. Intravascular ultrasound (IVUS) is a widely used conventional imaging modality for achieving optimal stent deployment. The aim of this study was to evaluate the impact of FD-OCT guidance for coronary stent implantation compared with IVUS guidance. Methods and Results— A total of 70 patients with de novo coronary artery lesions and either unstable or stable angina pectoris were enrolled in this randomized study (optical coherence tomography [OCT] group: n=35, IVUS group: n=35). In the OCT group, stent implantation was performed under FD-OCT guidance alone and final stent expansion was evaluated by IVUS. In the IVUS group, conventional IVUS guidance was used and final stent apposition was evaluated by FD-OCT. There were no significant differences regarding the procedural, fluoroscopy time, and contrast volume. Although device and clinical success rates also were similar, the visibility of vessel border was significantly lower in the OCT group ( P P P P =0.34). Conclusions— FD-OCT guidance for stent implantation was associated with smaller stent expansion and more frequent significant residual reference segment stenosis compared with conventional IVUS guidance.

Current observations were made from 14 July 2006 to 31 March 2007, using an acoustic Doppler current profiler mounted on the seafloor near the eastern coast of the Noto Peninsula, Japan, to investigate strong coastal currents induced by large-amplitude coastal-trapped waves (CTWs) and near-inertial fluctuations (NIFs). The CTWs were generated by the winter monsoon and the passage of a typhoon during the observation period. Two types of strong currents with velocities higher than 50 cm s –1 were observed. One type, the strong current in winter (SCW), had the coast on the left to its direction of flow. This current was observed after a strengthening of the winter monsoon in January 2007. The other type, the strong current in fall (SCF), had the coast on the right to its direction of flow and was observed after the passage of a typhoon in September 2006. The SCW was inferred to be formed mainly by low-mode CTWs without NIFs. Compared to the SCW, the SCF had a more complicated vertical structure and time variations. The SCF was inferred to be generated by low-mode CTWs strengthened by NIFs. The contributions of NIFs to the strong coastal currents became important when the wind stress direction was rotating clockwise.

OBJECTIVES The purpose of this study was to assess the prevalence and to quantify the thin-cap fibroatheroma (TCFA) and ruptured plaques in patients with coronary artery disease using optical coherence tomography (OCT). BACKGROUND TCFA lesions are the most prevalent precursors of plaque rupture, and are responsible for acute coronary syndromes (ACS). There are limited data regarding the frequency and distribution of TCFA in diseased coronary arteries. METHODS Coronary artery OCT was performed in 78 vessels in 47 patients, with stable angina (SA) or ACS. OCT plaque characteristics were derived using criteria that had been validated earlier. TCFA was defined as rich in lipid (two or more quadrants) with thin fibrous cap (

Objective This study compared the impact of pattern of sirolimus eluting stent restenosis (SES ISR) on the angiographic outcomes following conventional modalities of treatment. Methods A total of 344 consecutive patients who underwent treatment for SES ISR were included in the study. Lesions were divided into focal 10 mm, 188 (54.7%). The endpoints analysed were angiographic restenosis and target lesion revascularisation. A total of 31%, 41%, and 23% patients were treated with cutting balloon angioplasty, balloon angioplasty, and repeat stenting. Results Baseline characteristics were similar for two patterns, except for young age, more AMI and severe angina, more CTO lesions, long lesions, and more use of repeat stenting in non focal ISR group. Follow up angiography shows binary restenosis was significantly lower in the focal group (32.4% vs. 49.2; p =0.012) and target lesion revascularisation were also lower with focal pattern ISR (30.6 vs. 42.9; p =0.06). Restenosis rates are similar between balloon angioplasty and repeat stenting (28 vs. 23%) in focal ISR group, and repeat stenting showed better outcomes in the non focal group (60% vs. 36%). Conclusion The recurrent ISR remains high with available treatments and the pattern of SES ISR predicted the outcomes, with lower restenosis rates with focal pattern of ISR.

Objectives We performed this study to investigate with optical coherence tomography (OCT) the vascular response after sirolimus-eluting stent (SES) implantation between patients with and those without diabetes mellitus (DM). Background The difference in vascular response after SES implantation between patients with and those without DM has not been fully evaluated with OCT. Methods Optical coherence tomography was performed to examine 74 nonrestenotic SES implanted in 63 patients (32 with DM and 31 without DM) at 9 months after SES implantation. For struts showing neointimal coverage, the neointimal thickness on the luminal side of each strut section was measured, and neointimal characteristics were classified into high, low, and layered signal pattern. Results Baseline patient characteristics and lesion and procedural characteristics data were similar between the 2 groups. In total, 11,422 struts were analyzed. High signal neointima was observed in 90.2 ± 13.9%, low signal neointima in 7.3 ± 10.0%, and layered neointima in 2.7 ± 5.8%/stents. There was higher incidence of low signal neointima (10.5 ± 10.3% vs. 4.5 ± 5.6%, p = 0.003), neointimal thickness was larger (median: 106.8 μm, interquartile range: 79.3 to 130.4 μm vs. median: 83.5 μm, interquartile range: 62.3 to 89.3 μm; p Conclusions High signal neointimal pattern was predominantly observed, and low or layered signal pattern was observed in some cases. In DM patients, low signal neointima was observed with high frequency. Neointimal coverage and neointimal thickness was also higher in DM patients as compared with non-DM patients.

Objectives The aim of this study was to report the initial experience with a novel catheter in the retrograde approach for chronic total occlusion (CTO). Background Although the use of the retrograde approach in percutaneous coronary intervention for CTO has been established, some procedural difficulties remain. Methods A novel over-the-wire catheter (channel dilator) specifically designed for the retrograde approach has been developed for the treatment of CTO. The channel dilator was used in 93 CTO lesions after successful wiring of collateral channels using the retrograde approach. Results Successful channel crossing of the catheter was achieved in 90 of the lesions (96.8%), and the channel dilator successfully advanced into the occlusion reversely during retrograde wiring in 85 lesions (94.4%). Of the 75 lesions with successful advancement of the retrograde wire into the proximal true lumen, the entire occlusion was crossed retrograde with the channel dilator in 63 lesions (84.0%). To evaluate the feasibility of the catheter, 93 CTO lesions in the preceding period were compared. Procedure and fluoroscopy time tended to be lower in the study group than in the control group. The success of the retrograde procedure was significantly higher in the study group than in the control group (98.9% vs. 92.5%, p = 0.030). Conclusions The channel dilator may facilitate the conventional retrograde approach with a high level of success.

Objectives The study evaluates the feasibility and efficacy of the novel modification of the retrograde recanalization of the chronic total occlusion (CTO) of the coronary arteries by using intravascular ultrasound (IVUS)-guided reverse controlled antegrade and retrograde tracking (CART). Background Despite improvement in the techniques and materials, CTO recanalization is still suboptimal. The CART procedure has improved success rates, but there are certain inherent technical uncertainties and risk with this procedure. Methods This first series involves 31 patients, with 22 patients having previous failed attempts at CTO recanalization. All patients were treated with bilateral approach and using IVUS-guided reverse CART concept. Results Successful recanalization of the CTO was achieved in all cases (100%). The access route was septal collateral in 20 (70%) cases and epicardial collateral in 11 (30%) cases. IVUS guidance was used successfully in 30 cases, and the channel dilator (microcatheter) was used in 27 cases. Guidewire injury and grade 1 perforation was seen in 3 (9%) cases, which were managed conservatively. There was no death, coronary artery bypass surgery, or pericardiocentesis in this group of patients. Mean fluoroscopy time was 65.84 ± 23.16 min, ranging from 31 to 106 min and total contrast volume used 321.32 ± 137.77 ml (range 115 to 650 ml). Conclusions This first series describes a high success rate of CTO recanalization with IVUS-guided reverse CART in selected patients performed by an experienced operator.

Aims: This paper studies in-stent restenosis (ISR) after percutaneous coronary intervention (PCI) following bare-metal stent (BMS) and drug-eluting stent (DES) in all consecutive patients between 2004 and 2007 undergoing PCI for ISR lesions at our centre. Methods and results: We compared the clinical presentation, pattern and angiographic outcomes in 838 patients with BMS ISR (487) and SES ISR (351). About 18% of the patients presented with acute coronary syndrome with 2% presenting as ST elevation myocardial infarction, similar in both groups. Angiographic pattern was predominantly focal with SES ISR (47%SES ISR vs. 19% BMS ISR; p

Objectives We sought to report the results of both bench-testing and our first clinical experience with this novel technique. Background The optimal stenting technique for bifurcation lesions has yet to be defined. Methods This technique works by flaring the proximal side of the stent in side branch out like a flower petal. We tested it in vitro and the resultant stent structure and stent polymer damage was observed in both main branch and side branch with an optical microscopy, multislice computer tomography, intravascular ultrasound, endoscopy, and by electron microscopy. We also applied this technique in 33 patients and assessed patient outcomes up to 9 months prospectively. Drug-eluting stents were used for the bench tests and for all patients. Results Bench-testing showed complete coverage of the bifurcation with minimal stent-layer overlapping. There was little polymer damage by electron microscopy. Procedural success was achieved in all cases and restenosis occurred in 2 cases. In both restenosis cases, “petal” stenting technique was done reluctantly after another stent had already been deployed in the main branch before any stenting of the side branch. There were no incidences of restenosis when this technique was used electively. Conclusions In terms of damage to the polymer and ostial strut coverage, this new “flower petal stenting” technique is effective for treatment of bifurcation lesion and it may well be superior to other available techniques.

We examined the surface current structure in the Tsushima Warm Current (TWC) region of the Japan Sea based on a dataset from satellite-tracked surface drifters, including our new deployments during 2004–2008. The gridded mean current velocity and mean kinetic energy (KE) fields calculated from all available drifter data revealed the structure and seasonality of the three branches of the TWC. By comparing the eddy kinetic energy (EKE) field to the KE field, we found four regions where the ratio of EKE to KE was high. In particular, this ratio became extremely high east of the Oki Islands located between the first branch of the TWC (FBTWC) and the second branch of the TWC (SBTWC). Our analysis suggests that the generation of alternate warm and cold eddies east of the Oki Island induced this high ratio. The occurrence of a warm or cold eddy was related to the route—either nearshore or offshore—of the SBTWC. When the offshore route of the SBTWC became dominant, a warm eddy was frequently generated east of the Oki Islands. In contrast, when the nearshore route of the SBTWC became dominant, a cold eddy was more likely to be generated.

Objectives The aim of this study was to evaluate the safety and feasibility of a new concept for chronic total occlusion (CTO) recanalization—using a bilateral approach that utilizes a Controlled Antegrade and Retrograde subintimal Tracking (CART) technique. Background Successful percutaneous recanalization of coronary CTOs results in improved long-term outcomes. The recanalization of CTOs in native coronary arteries no doubt represents one of the most technically challenging of interventional procedures. Methods A total of 224 consecutive patients (mean age 61 ± 9 years; 86.2% men) were enrolled in this prospective multicenter registry. This technique combines the simultaneous use of antegrade and retrograde approaches. A subintimal dissection is created in both antegrade and retrograde fashion, thereby limiting the extension of the subintimal dissection within the CTO portion. Results Of 224 CTO lesions (>3 months in duration) undergoing attempted recanalization using the CART technique, 145 cases (64.7%) had undergone previous CTO recanalization attempts. The success rates of crossing in a retrograde fashion with a wire and a balloon were 87.9% and 79.9%, respectively. The overall technical and procedural success rates achieved in this registry were 92.4% and 90.6%, respectively. Conclusions A bilateral approach for CTO lesions using the CART technique is feasible, safe, and has a higher success rate than previous approaches. These results indicate that a bilateral technique can solve a major dilemma that commonly affects CTO procedures.

The aim of this study was to examine the procedural success and in-hospital outcomes after percutaneous coronary intervention (PCI) for chronic total occlusions in the current era during contemporary practice. The technique of PCI has improved over time with the introduction of novel equipment and guidewire crossing techniques. However, there is limited data available from contemporary practice in the recent years. We evaluated the procedural and in-hospital outcomes in a consecutive series of 904 procedures performed at Toyohashi Heart Center for PCI of chronic total occlusions of >3 months in duration. Technical and procedural success was achieved in 87.5% and 86.2%, respectively. In-hospital major adverse cardiac events occurred in only 1.9% of the patients. Single antegrade wire was the predominant strategy for guidewire crossing; however, retrograde guidewire crossing was used in 7.2% of the cases and controlled antegrade and retrograde subintimal tracking in 9.9% of the cases as the final strategy. Logistic regression analysis identified severe tortuosity and moderate-to-severe calcification as significant predictors of procedural failure. This is the first reported large series of patients undergoing PCI for chronic total occlusion with improved wire crossing techniques. We have reported high success rates in recent years and very low complication rates despite the use of more aggressive devices and techniques.

Background— Retrograde approach through collaterals has been introduced for percutaneous recanalization of chronic total occlusion (CTO) of the coronary arteries. We investigated the safety and efficacy of retrograde approaches used for percutaneous recanalization of CTO in a consecutive series of patients. Methods and Results— We studied 157 consecutive patients who underwent retrograde CTO recanalization between 2003 and 2008 at a single center. A total of 118 (75.2%) of these patients have had previously failed antegrade attempts. Septal, epicardial, and saphenous vein graft collaterals were used in 67.5%, 24.8%, and 7.6% of cases, respectively. Collateral channel was crossed by guide wire successfully in 115 (73.2%) cases, and the procedure was successful by retrograde approach in 103 (65.6%) cases. Collateral channels (CCs) were graded as follows: CC0, no continuous connection; CC1, continuous thread-like connection; and CC2, continuous, small sidebranch-like connection. CC1, collateral tortuosity P P =0.01), CC0, corkscrew channel ( P 90� ( P =0.0007), and nonvisibility of connection with recipient vessel were found to be significant predictors of procedural failure. The CC dissection was observed in 6 patients, with 1 needing coil embolization and others who were managed conservatively. The major adverse cardiac events were low, with 1 coronary artery bypass graft, 1 Q-wave myocardial infarction, 5 non–Q-wave myocardial infarctions, and no deaths in this group of patients. Conclusions— The retrograde approach in CTO percutaneous coronary intervention is effective in recanalizing CTO. The success rate by retrograde approach was 65.6%, and final success was 85% in this group with acceptable overall adverse events. We have identified predictors of failure related to collateral morphology.

In percutaneous coronary intervention for chronic total occlusion (CTO), the retrograde approach is an advanced technique. To improve the long-term patency rate, stent implantation is necessary for CTO, however, antegrade stent delivery to the lesion is contraindicated in cases where there is an anomalous origin or deviation of the coronary artery, or the edge of a previously implanted stent extends into the aorta. We report a successful case of retrograde stent implantation via a septal perforator in a patient with marked deviation of the RCA origin. In this case, antegrade stent implantation was difficult because antegrade catheter insertion carried a risk of crush deformation of an ostial stent. © 2009 Wiley-Liss, Inc.

OBJECTIVES: This study sought to evaluate the diagnostic accuracy of coronary binary in-stent restenosis (ISR) with angiography using 64-slice multislice computed tomography coronary angiography (CTCA) compared with invasive coronary angiography (ICA). BACKGROUND: A noninvasive detection of ISR would result in an easier and safer way to conduct patient follow-up. METHODS: We performed CTCA in 81 patients after stent implantation, and 125 stented lesions were scanned. Two sets of images were reconstructed with different types of convolution kernels. On CTCA, neointimal proliferation was visually evaluated according to luminal contrast attenuation inside the stent. Lesions were graded as follows: grade 1, none or slight neointimal proliferation; grade 2, neointimal proliferation with no significant stenosis ( or =50%); and grade 4, neointimal proliferation with severe stenosis (> or =75%). Grades 3 and 4 were considered binary ISR. The diagnostic accuracy of CTCA compared with ICA was evaluated. RESULTS: By ICA, 24 ISRs were diagnosed. Sensitivity, specificity, positive predictive value, and negative predictive value were 92%, 81%, 54%, and 98% for the overall population, whereas values were 91%, 93%, 77%, and 98% when excluding unassessable segments (15 segments, 12%). For assessable segments, CTCA correctly diagnosed 20 of the 22 ISRs detected by ICA. Six lesions without ISR were overestimated as ISR by CTCA. As the grade of neointimal proliferation by CTCA increases, the median value of percent diameter stenosis increased linearly. CONCLUSIONS: Binary ISR can be excluded with high probability by CTCA, with a moderate rate of false-positive results.

By using Acoustic Doppler Current Profiler (ADCP) measurements with the four round-trips method to remove diurnal/semidiurnal tidal currents, the detailed current structure and volume transport of the Tsushima Warm Current (TWC) along the northwestern Japanese coast in the northeastern Japan Sea were examined in the period September–October 2000. The volume transport of the First Branch of the TWC (FBTWC) east of the Noto Peninsula was estimated as approximately 1.0 Sv (106 m3/s), and the FBTWC continued to flow along the Honshu Island to the south of the Oga Peninsula. To the north of the Oga Peninsula, the Second Branch of Tsushima Warm Current and the eastward current established by the subarctic front were recombined with the FBTWC and the total volume transport increased to 1.9 Sv. The water properties at each ADCP line strongly suggested that most of the upper portion of the TWC with high temperature and low salinity flowed out to the North Pacific as the Tsugaru Warm Current. In the north of the Tsugaru Strait, the volume transport of the northward current was observed to be as almost 1 Sv. However, the component of the TWC water was small (approximately 0.3 Sv).

OBJECTIVES The goal of the present study was to compare the accuracy of in vivo tissue characterization obtained by intravascular ultrasound (IVUS) radiofrequency (RF) data analysis, known as Virtual Histology (VH), to the in vitro histopathology of coronary atherosclerotic plaques obtained by directional coronary atherectomy. BACKGROUND Vulnerable plaque leading to acute coronary syndrome (ACS) has been associated with specific plaque composition, and its characterization is an important clinical focus. METHODS Virtual histology IVUS images were performed before and after a single debulking cut using directional coronary atherectomy. Debulking region of in vivo histology image was predicted by comparing pre- and post-debulking VH images. Analysis of VH images with the corresponding tissue cross section was performed. RESULTS Fifteen stable angina pectoris (AP) and 15 ACS patients were enrolled. The results of IVUS RF data analysis correlated well with histopathologic examination (predictive accuracy from all patients data: 87.1% for fibrous, 87.1% for fibro-fatty, 88.3% for necrotic core, and 96.5% for dense calcium regions, respectively). In addition, the frequency of necrotic core was significantly higher in the ACS group than in the stable AP group (in vitro histopathology: 22.6% vs. 12.6%, p = 0.02; in vivo virtual histology: 24.5% vs. 10.4%, p = 0.002). CONCLUSIONS Correlation of in vivo IVUS RF data analysis with histopathology shows a high accuracy. In vivo IVUS RF data analysis is a useful modality for the classification of different types of coronary components, and may play an important role in the detection of vulnerable plaque.

Background Multislice computed tomography (MSCT) is a promising noninvasive method of detecting coronary artery disease (CAD). However, most data have been obtained in selected series of patients. The purpose of the present study was to investigate the accuracy of 64-slice MSCT (64 MSCT) in daily practice, without any patient selection. Methods and Results Using 64-slice MSCT coronary angiography (CTA), 69 consecutive patients, 39 (57%) of whom had previously undergone stent implantation, were evaluated. The mean heart rate during scan was 72 beats/min, scan time 13.6 s and the amount of contrast media 72 mL. The mean time span between invasive coronary angiography (ICAG) and CTA was 6 days. Significant stenosis was defined as a diameter reduction of >50%. Of 966 segments, 884 (92%) were assessable. Compared with ICAG, the sensitivity of CTA to diagnose significant stenosis was 90%, specificity 94%, positive predictive value (PPV) 89% and negative predictive value (NPV) 95%. With regard to 58 stented lesions, the sensitivity, specificity, PPV and NPV were 93%, 96%, 87% and 98%, respectively. On the patient-based analysis, the sensitivity, specificity, PPV and NPV of CTA to detect CAD were 98%, 86%, 98% and 86%, respectively. Eighty-two (8%) segments were not assessable because of irregular rhythm, calcification or tachycardia. Conclusion Sixty-four-MSCT has a high accuracy for the detection of significant CAD in an unselected patient population and therefore can be considered as a valuable noninvasive technique. (Circ J 2006; 70: 564 - 571)

In Part I of this article, the definitions, prevalence, and clinical presentation of chronic total occlusions (CTOs) were reviewed, the histopathology of CTOs was examined, efforts to replicate human CTOs with experimental models were appraised, and the clinical relevance and rationale for CTO revascularization were evaluated.1 In Part II, we summarize the technical approach to and outcomes after percutaneous coronary intervention (PCI) of occluded coronary arteries, describe the novel devices and drugs approved and undergoing investigation for CTO recanalization, and conclude with practical perspectives on managing the patient with 1 or more chronic coronary occlusions. ### Patient Selection and Revascularization Strategies PCI of CTOs constitutes as many as 20% of all angioplasty procedures at selected centers,2 although a rate of &10% is more typical,3–6 suggesting that CTO angioplasty is attempted in 50 000 to 100 000 patients per year in the United States. Many more CTOs are present for which PCI is never attempted, representing one of the most common causes for referral to bypass surgery rather than PCI.6–8 Furthermore, a large proportion of patients with CTOs are managed medically, the prognosis of whom may vary depending on the extent of viable myocardium and ischemia, concomitant atherosclerosis in other coronary and noncoronary vascular territories, and other comorbid conditions. The decision to attempt PCI of a CTO (versus continued medical therapy or surgical revascularization) requires an individualized risk/benefit analysis, encompassing clinical, angiographic, and technical considerations. Clinically, the patient’s age, symptom severity, associated comorbidities (eg, diabetes mellitus and chronic renal insufficiency), and overall functional status are major determinants of treatment strategy. Angiographically, the extent and complexity of coronary artery disease (eg, single-vessel versus multivessel disease, single versus multiple total occlusions, likelihood for complete revascularization), left ventricular function, and the presence and degree of valvular heart disease should be considered. The technical probability of achieving …