Coronary Artery Chronic Total Occlusion Research Articles

Abstract 13502: Prognostic Significance of Non-Infarct-Related Coronary Artery Chronic Total Occlusion in Patients Presenting With Acute Myocardial Infarction: A Systematic Review and Meta-Analysis

Introduction: In patients with acute myocardial infraction (AMI), multivessel coronary artery disease (CAD) is associated with worse prognosis than single-vessel CAD. Several observational studies have reported worse clinical outcomes in AMI patients with non-infarct-related artery chronic total occlusion (n-IRA CTO). We performed a systematic review and meta-analysis to evaluate the prognostic significance of n-IRA CTO in patients with AMI. Methods: Systematic review was performed querying PubMed, Google Scholar, Cochrane and clinicaltrials.gov from Inception through May 2022. Studies comparing AMI patients with and without n-IRA CTO were included. Outcomes included in-hospital, 30-day and long-term mortality, cardiac mortality, major adverse cardiovascular events (MACE), and major bleeding. Risk ratios (RRs) and 95% confidence intervals (CIs) were calculated using random effects models. Results: Five prospective, eight retrospective and 3 subgroup analyses of randomized control trials (RCTs) (n-IRA CTO n=2,521, no CTO n=18,397) were identified. Presence of n-IRA CTO was associated with higher in-hospital (RR 2.86, 95% CI 1.77-4.62, p<0.0001, Figure A), 30-day (RR 2.54, 95% CI 1.66-3.89, p<0.00001, B) and long-term mortality (RR 2.32, 95% CI 1.81-2.99, p<0.00001, C), as well as increased risk for cardiac mortality (RR 2.24, 95% CI 1.79-2.81, p<0.0001, D), MACE (RR 1.51, 95% CI 1.32-1.74, p<0.0001, E), and major bleeding (RR 1.99, 1.16-3.41, p=0.01, F) when compared to AMI patients without n-IRA CTO. Conclusions: In AMI patients, the presence of n-IRA CTO is associated with increased mortality and morbidity. Future studies should evaluate whether intensive monitoring and specialized care can improve outcomes in these patients.

Abstract 11623: Retrograde Facilitated Antegrade Dissection and Re-Entry

History: A 69-year-old man presented with severe medically refractory stable angina and was referred for revascularization of a right coronary artery (RCA) chronic total occlusion (CTO Figure 1.A ). The patient had undergone coronary artery bypass surgery 16 years prior as well as numerous percutaneous coronary intervention. Echocardiography demonstrated normal left ventricular systolic function. Procedure: Antegrade wiring was attempted first with a Fielder XT guidewire (GW) and a Turnpike Spiral microcatheter (MC Figure 1.B ). Due to the ambiguous proximal cap and long occlusion length, retrograde crossing was attempted next. After attempting to cross multiple collaterals a Sion Black crossed a proximal septal collateral ( Figure 1.C ), but several MCs could not follow the GW, despite ballooning the collateral with a 1.5 mm balloon and GuideLiner support. We switched to antegrade dissection and re-entry with a knuckled Gladius Mongo that reached the distal RCA ( Figure 1.D ). With the Stingray balloon and ‘double blind stick and swap’ technique we crossed into the distal true lumen, but the GW position was lost after removal of the balloon. We crossed with the retrograde GW to the antegrade guide catheter (Figure 1.E) , but ‘tip in’ technique as well as passing the retrograde MC was not successful. Using a new Stingray balloon and the retrograde GW as true lumen marker ( Figure 1.F ) we crossed into the distal true lumen. After drug-eluting stent implantation ( Figure 1.G ) the distal bifurcation was recanalized with kissing balloon dilation ( Figure 1.H ) and implantation of another stent with a nice final result ( Figure 1.I ). Conclusion: Persistence is key in CTO PCI in patients with severe medically refractory stable angina and limited revascularization options. Crossing the collaterals with MC can be challenging: possible solutions are smaller MC, predilation in septal collateral, ‘tip in’ or switching to another crossing strategy such as ADR with retrograde facilitation.

The relationship between mean platelet volume lymphocyte ratio and collateral circulation in patients with chronic total coronary occlusion.

To correlate mean platelet volume lymphocyte ratio (MPVLR) and coronary collateral circulation (CCC) in patients with chronic total occlusion (CTO). A total of 643 patients who were hospitalized at a single large academic medical center from January 2020 to October 2021 and had CTO lesions in at least one major coronary artery confirmed by coronary angiography were retrospectively analyzed. Patients were divided according to the Rentrop criteria into poorly formed CCC (Rentrop grade 0-1, n = 235) and well-formed CCC (Rentrop grade 2-3, n = 408) groups. Mean platelet volume lymphocyte ratio (MPVLR) was calculated from routine laboratory data (MPV divided by lymphocyte count). The clinical data of the two groups were compared, and relationships between MPVLR and CCC formation were analyzed. The MPVLR of patients with poorly formed CCC was significantly higher than that of patients with well-formed CCC (7.82 ± 3.80 vs. 4.84 ± 1.42, P < 0.01). The prevalence of diabetes mellitus and C-reactive protein levels were significantly higher in the poor CCC group than in the good CCC group (P < 0.01), while the proportions of patients with CTO or multivessel lesions in the right coronary artery were significantly lower in the poor CCC group than in the good CCC group (P < 0.01). Multivariate logistic regression analysis identified MPVLR (OR: 2.101, 95% CI: 1.840-2.399, P < 0.01), C-reactive protein level (OR: 1.036, 95% CI: 1.008-1.064, P < 0.05), a history of diabetes mellitus (OR: 2.355, 95% CI: 1.532-3.621, P < 0.01), and right coronary CTO ratio (OR: 0.313, 95% CI: 0.202-0.485, P < 0.01) as independent risk factors for CCC formation. The area under the ROC curve of MPVLR for predicting poorly formed CCC was 0.82 (95% CI: 0.784-0.855, P < 0.01), the best cut-off point was 6.02 and the sensitivity and specificity of MPVLR for predicting poorly formed CCC were 72.3 and 82.4%, respectively. In patients with coronary CTO, MPVLR was negatively correlated with CCC and a high MPVLR level was an independent predictor of poorly formed CCC.

Percutaneous treatment of a CTO in an anomalous right coronary artery: A rupture paved the way for new insights.

An anomalous aortic origin of a coronary artery (AAOCA) from the opposite sinus, with an interarterial course, has been associated with an increased risk of myocardial ischemia and sudden death. As the exact pathophysiology of AAOCA is not well understood, the clinical management is also not well defined. With increased use of non-invasive imaging, the diagnosis of AAOCA is increasing and the association of anomalous origin and atherosclerotic disease is becoming a more important topic. We report a rare case of AAOCA chronic total occlusion (CTO). A 40-year-old Caucasian man was referred for invasive coronary angiography (ICA) due to typical chest pain and positive myocardial scintigraphy. ICA demonstrated CTO of an anomalous right coronary artery (ARCA) originating from the left side of the ascending aorta with an interarterial course. There was no lesion in the left coronary artery. During the procedure, unexpected rupture of the coronary artery occurred after dilatation with a small balloon at low pressure. The complication in this case was handled with good procedural final result but was an occasion for a food for thought. Coronary artery perforations are rare but life-threatening procedural complications that are usually caused by predisposing anatomical and procedural factors. We issue a warning on the risk of complications during complex percutaneous coronary intervention of these arteries, and we reconsidered the pathophysiology of the anomaly in a way that could change the approach to the disease. Based on this complication, we hypothesized that the wall of the artery could be fragile due to histopathological alterations, which could have a role in the pathophysiology of coronary malignancy. Future autopsy studies should be focused on the analysis of the arterial wall of the patient affected by sudden death with this anomaly.

Relationship between Systemic Immune-Inflammation Index and Coronary Collateral Circulation in Patients with Chronic Total Occlusion.

ResumoFundamento A inflamação desempenha um papel fundamental no início e na progressão da doença arterial coronariana (DAC). O Índice Imune-inflamação Sistêmico (SII) é um novo parâmetro inflamatório que demonstrou estar associado à DAC.Objetivos Este estudo teve como objetivo investigar a relação entre o SII e a circulação colateral coronariana (CCC) em pacientes com DAC estável e oclusão crônica total (OTC).Métodos Os pacientes foram divididos em dois grupos, com CCC deficiente e CCC boa, de acordo com a Classificação Rentrop. Noventa e quatro pacientes apresentavam CCC deficiente e 81 pacientes CCC boa. Os parâmetros de inflamação foram calculados a partir dos resultados laboratoriais. O nível de significância estatística aplicado foi de 0,05.Resultados Alto nível de SII (OR: 1,003, IC 95%: 1,001-1,004, p<0,001), ausência de OTC na ACD (artéria coronária direita) (OR: 0,204, IC 95%: 0,096-0,436, p<0,001) e baixo escore de Gensini (OR: 0,980, IC 95%: 0,962-0,998, p=0,028) foram significantemente associados com CCC deficiente. O valor de corte do SII foi de 679,96 para o maior poder preditivo de CCC deficiente, com sensibilidade de 74,5% e especificidade de 43,2%. As taxas de mortalidade foram semelhantes entre os dois grupos durante um seguimento médio de 21,5±10,8 meses (p=0,107).Conclusões Alto nível de SII, ausência de OTC na artéria coronária direita e baixo escore de Gensini foram significantemente relacionados à CCC deficiente. O uso rápido e custo-efetivo de novos marcadores inflamatórios na prática clínica orienta o prognóstico da DAC.

Risk Burden of Coronary Perforation in Chronic Total Occlusion Recanalization: Latin American CTO Registry Analysis.

BackgroundCoronary perforation is a life‐threatening complication of acute percutaneous coronary intervention (PCI) for chronic total occlusions (CTO), but data on midterm outcomes are limited.Methods and ResultsData from LATAM (Latin American)‐CTO Registry (57 centers; 9 countries) were analyzed. We assessed the risk of 30‐day, 1‐year major adverse cardiac events of coronary perforation using time‐to‐event and weighted composite end point analysis having CTO PCI without perforation as comparators. Additionally, we studied the independent predictors of perforation in these patients. Of 2054 patients who underwent CTO PCI between 2015 and 2018, the median Multicenter CTO Registry in Japan and Prospective Global Registry for the Study of Chronic Total Occlusion Intervention‐Chronic total occlusions scores were 2.0 (1.0–3.0) and 1.0 (0.0–2.0), respectively. The perforation rate was 3.7%, of which 55% were Ellis class 1. After 1‐year coronary perforation had higher major adverse cardiac events rates (24.9% versus 13.3%; P<0.01). Using weighted composite end point, perforation was associated with increased bleeding and ischemic events at 6 months (P=0.04) and 1 year (P<0.01). We found as independent predictors associated with coronary perforation during CTO PCI: maximum activated clotting time (P<0.01), Multicenter CTO Registry in Japan score ≥2 (P=0.05), antegrade knuckle wire (P=0.04), and right coronary artery CTO PCI (P=0.05).ConclusionsCoronary perforation was infrequent and associated with anatomical and procedural complexity, resulting in higher risk of hemorrhagic and ischemic events. Landmark and weighted analysis showed a sustained burden of major events between 6 months and 1 year follow‐up.

P59 A COMPLEX PCI IN A CARDIOGENIC SHOCK NSTEMI PATIENT NEEDING PTA AND LEFT VENTRICLE ASSISTANCE

Abstract A 72–years–old man, smoker, type 2 DM and hypertension in history, was admitted for NSTEMI complicated by cardiogenic shock; Echocardiogram revealed LV dilatation with severe disfunction (EF 20%), moderate mitral regurgitation; he started inotropic support and high dose diuretics, then he needed dialysis and positioning of a temporary PM. Coronary angiography revealed chronic total occlusion (CTO) of the left anterior descending artery (LADA) and CTO of the right coronary artery (RCA). A first CTO PCI procedure was attempted for the LADA occlusion, with the support of IABP, using an antegrade approach, polimeric wire (ASAHI Fielder) and more penetrating ones (ASAHI Gaia I and II), unable to gain the true lumen beyond the occlusion. A second attempt was planned, with the support of Impella CP device for left ventricle assistance; due to critical stenosis in the right common iliac artery, a PTA with stenting (8/38 mm) was preparatory for that. For the second attempt a dual coronary approach was prepared (6 F Amplatz left 1,0 for RCA and 7 F XB 3,5 for left coronary artery); at first a novel antegrade attempt was pursued with a step–up technique (ASAHI wires: Gladius, Gaia I, II and III, Conquest pro), ineffective to reach the true lumen distally the occlusion. The retrograde approach was then pursued, through a collateral originating from the acute marginal branch of the RCA to the distal segment of LADA, using the Caravel microcatheter with ASAHI wires Sion blue, Sion black, Suoh 03, effective to reach the distal cap of the occlusion, this one passed by the Gladius wire. The ASAHI RG3 externalization wire (330 mm) was then used, entering from the radial access and the amplatz catheter for the RCA, reaching the XB catheter in the left coronary artery through a Guideliner extension catheter, and externalized in the femoral access. IVUS analysis was then used to confirm good wire position and the vessel calibers, so pre–dilatation was done and 3 drug–eluting stents were implanted (2,25/23 + 3,25/38 + 3,5/18 mm) distal–to–proximal overlap, with final post–dilatation, obtaining a good final result on angiography and IVUS. During the 4–hours procedure clinical condition was stable and Impella was removed with a rapid weaning; the double pre–mounted Proglide device was used for femoral hemostasis. 5 days after the patient was discharged, II–III NYHA class, 25% EF. At the 3 months f–up he was asymptomatic in good clinical condition, 30% EF, he refused ICD implant.

Recanalizing a right coronary artery chronic total occlusion with J chronic total occlusion score 3

We represent a case of interesting right coronary artery chronic total occlusion (CTO) revascularization where traditional wire upgradation failed to cross the CTO. Downgrading it to a Miracle 3 wire, the lesion was successfully crossed. It was further dilated with the smallest balloon (NIC Nano 0.85 mm × 6 mm), followed by serial dilation with bigger size balloons. The present manuscript conveys a message that the rule of thumb of wire upgradation during CTO revascularization does not yield in success always, it is the downgradation of the wire which can also achieve success. CTO revascularization although it has some fixed principles, sometimes, a permutation and combination even giving a fair try with wire downgradation can achieve success.

TCTAP C-117 Wire Perforation in Posterior Lateral Artery Treated With Coil During Right Coronary Artery Chronic Total Occlusion Intervention

TCTAP C-117 Wire Perforation in Posterior Lateral Artery Treated With Coil During Right Coronary Artery Chronic Total Occlusion Intervention

TCTAP C-053 A Challenging Right Coronary Artery Chronic Total Occlusion Required Hybrid Approach and Multiple Troubleshooting to Achieve Success

TCTAP C-053 A Challenging Right Coronary Artery Chronic Total Occlusion Required Hybrid Approach and Multiple Troubleshooting to Achieve Success

TCTAP C-060 Rock-Hard Right Coronary Artery Chronic Total Occlusion Intervention and Thrilling Complication

TCTAP C-060 Rock-Hard Right Coronary Artery Chronic Total Occlusion Intervention and Thrilling Complication

TCTAP C-087 Revascularization in Patient With Left Main Coronary Artery Chronic Total Occlusion and Left Ventricular Dysfunction

TCTAP C-087 Revascularization in Patient With Left Main Coronary Artery Chronic Total Occlusion and Left Ventricular Dysfunction

Factors associated with all-cause mortality in patients with coronary artery chronic total occlusions undergoing revascularization (percutaneous coronary intervention or surgery) or medical treatment.

Aim Chronic total occlusion of a coronary artery (CTO) is a predictor of early and late cardiovascular mortality and poor cardiovascular outcomes in patients with coronary artery disease. The purpose of this study was to identify predictors of all-cause mortality in CTO patients that underwent invasive treatment.Material and methods Patients between 2012 and 2018 with CTO in at least one vessel, as demonstrated by coronary angiography, were included retrospectively in the study. The patients were divided into two groups, an intervention group (percutaneous and surgical revascularization) and a medical group.Results A total of 543 patients were studied, 152 females (28%) and 391 males (72%). The median follow-up period was 49 (26-72) mos. A total of 186 (34.2%) patients in the medical group and 357 (65.8%) patients in the invasive therapy group were followed. The 5-yr death rate was observed in 50 (26.9%) patients in the medical group and 53 (14.8%) patients in the intervention group, and it was found to be statistically higher in the medical group (p=0.001). In multivariable analysis, heart failure (odds ratio (OR): 1.92, 95% CI: 1.18-3.14; p=0.01), higher glucose levels (OR: 1.05, 95% CI: 1,02-1.08; p=0.04), lower albumin levels (OR: 0.49, 95% Cl: 0.32-0.72; p=0.001), SYNTAX score (OR: 1.03, 95% CI: 1.01-1.05; p=0.001), and CTO (≥2 occluded artery) (OR: 0.42, 95% CI: 0.22-0.72; p=0.01) were independent factors for all-cause mortality.Conclusion In comparison to the revascularized group, there was an increase in mortality among CTO patients treated medically. Heart failure, SYNTAX score, albumin, glucose, and CTO (≥2 occluded arteries) were independent risk factors for all-cause mortality.

A novel use of small ballons to reduce the risk of subintimal hematoma formation during recanalization of chronic total occlusion: two case reports

BackgroundSubintimal hematoma remains a major challenge associated with unnecessary technical complexity, failure of the antegrade approach or imperfection of revascularization in percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). Some techniques and devices release the hematoma after its formation. Here, we describe a novel use of small ballons to prevent the hematoma formation during antegrade approach in two cases.Case presentationWe report two cases of CTO-PCI in which balloon occlusion was successfully applied to prevent haematoma formation. The first case, a 72-year-old female with diabetes, was hospitalized because of unstable angina. Angiography showed right coronary artery (RCA) CTO, which initiated from the proximal part to the trifurcation at the distal part of the RCA. Considering the high likelihood and serious consequences of subintimal haematoma, a small balloon is employed to prevent subintimal hematoma formation. A balloon and microcatheter or double-lumen microcatheter are placed in the proximal coronary CTO lesion; then the balloon was dilated beside the catheter, most of the antegrade blood flow was sealed which reduced the likelihood of haematoma formation. The procedure was successfully completed without subintimal hematoma formation. The second case a 62-year-old male with unstable angina, was hospitalized for PCI. Angiography showed left anterior descending coronary artery CTO. Similar to case 1, we also used a small balloon to prevent hematoma formation. Both patients underwent PCI, which employed a small balloon to prevent hematoma formation and both procedures were successful without complications.ConclusionIn patients who underwent CTO-PCI, balloon occlusion offers an alternative for reducing the incidence of subintimal haematomas.

Stress perfusion cardiovascular magnetic resonance and serial fractional flow reserve assessment of the left anterior descending artery in patients undergoing right coronary artery chronic total occlusion revascularization.

BackgroundFractional flow reserve (FFR) assessment of remote arteries, in the context of a bystander chronic total occlusion (CTO), can lead to false positive results. Adenosine stress cardiovascular magnetic resonance (CMR) evaluates perfusion defects across the entire myocardium and may therefore be a reliable tool in the work-up of remote lesions in CTO patients. The IMPACT-CTO study investigated donor artery invasive physiology before, immediately post, and at 4 months following right coronary artery (RCA) CTO percutaneous coronary intervention (PCI). The aim of this subanalysis was to assess the concordance between baseline perfusion CMR and serial FFR evaluation of left anterior descending artery (LAD) ischemia in patients from the IMPACT-CTO study.MethodsBaseline adenosine stress CMR examinations from 26 patients were analyzed for qualitative evidence of LAD ischemia. The results were correlated with the serial LAD FFR measurements.ResultsThe present findings demonstrated that before RCA CTO PCI, there was 62% agreement between perfusion CMR and FFR (ischemic threshold ≤ 0.8) in the assessment of LAD ischemia (k = 0.29; fair concordance). At 4 months after revascularization, there was 77% agreement (k = 0.52; moderate concordance) between the index CMR assessment of LAD ischemia and the follow-up LAD FFR. Concordance was improved at a LAD FFR ischemic threshold of ≤ 0.75.ConclusionsIn this hypothesis generating study, baseline CMR assessment of LAD ischemia correlated better with the 4 months LAD FFR data (threshold ≤ 0.8) as compared to the FFR measurements taken prior to RCA CTO revascularization.

Large False Lumen Prevailed After Coronary Dissection and Intramural Haematoma Fenestration With Cutting Balloon

A 55-year-old man had undergone percutaneous coronary intervention for right coronary artery (RCA) chronic total occlusion 2 years ago. The 3.0-mm balloon dilatation created coronary dissection and an intramural haematoma (IMH). The intravascular ultrasound revealed a no-reflow phenomenon with a large IMH extending to the distal RCA bifurcation. A stent was implanted to cover the proximal dissection and IMH entry site. The distal IMH was rescued by coronary fenestration with a 3.0-mm cutting balloon (Figure 1A).

Chronic Total Occlusion Anatomy and Characteristics of Coronary Collaterals and Angiographic Features Predicting the Success of Chronic Total Occlusion Intervention

Background and Objective: Angiographic assessment of chronic total occlusion (CTO) anatomy and collateral characteristics of coronary arteries are necessary for CTO intervention. Materials and Methods: This was a hospital-based observational study of 100 coronary angiograms (CAG) with CTOs. CTO anatomy and collateral characteristics of coronary arteries were studied for predicting anterograde and retrograde CTO intervention. Results: Right coronary artery (RCA) CTO was the most common (62%), followed by left anterior descending (LAD). More than two-thirds of RCA and LAD CTO lesions were &gt;20 mm and half were in mid-segment. Left circumflex artery (LCX) and RCA lesions were more frequently calcified. LAD CTOs often had blunt stump; LCX CTOs frequently had bending &gt;45°. The mean J-CTO score was lowest in RCA CTOs (2.0 ± 1.19). There were 10 different types of collaterals in RCA CTOs, 8 in LAD CTOs, and only 4 in LCX CTOs. The most common RCA CTOs collateral was LAD septal to the right posterior descending artery (RPDA) (69.4%) and in LAD CTOs, the most common was septal collaterals from the RPDA to LAD (40.9%). RCA CTOs had a higher percentage of septal collaterals, less tortuosity, and favorable entry and exit angle when compared with other two arteries. Conclusion: RCA CTOs were the most common. Angiographic features in CTO lesions vary among three major coronary arteries. The RCA CTOs had lesser mean J-CTO score, more number of septal collaterals, less tortuous collaterals, and favorable entry and exit angle. RCA CTOs were better accessible for anterograde and retrograde intervention.

ЭКОНОМИЧЕСКАЯ ЭФФЕКТИВНОСТЬ ИСПОЛЬЗОВАНИЯ РАЗЛИЧНЫХ ТИПОВ СТЕНТОВ ПРИ КОРРЕКЦИИ ХРОНИЧЕСКИХ ОККЛЮЗИЙ КОРОНАРНЫХ АРТЕРИЙ

Aim. To study cost-effectiveness of different types of stents in the correction of chronic total occlusion (CTO). Methods. The study included 119 patients after successful coronary artery CTO recanalization in 2009–2012. After 6.1±0.9 months and 12.7±1.6 months a control examination was performed (coronary angiography, intravascular ultrasound, optical coherence tomography). Negative events (in-stent restenosis and thrombosis) were analyzed. Taking into account the obtained data, direct costs were calculated including the cost of implants, and the cost of restenosis and thrombosis treatment. Results. The highest frequency of in-stent restenosis (p &lt; 0.05) was registered after IntrepideTM (in 57.1% cases) and Prolim® (in 47.4% cases) stent implantation while the similar events in cases of Taxus® Express 2, Xience V®/Xience Prime® LL, Endeavor® Resolute, Nobori® stent implantation were registered in 0-11.1% of cases. There weren’t differences in the thrombosis incidence between studied types of implants (p &gt; 0.05). Based on the data obtained, the stents were classified as devices with low rate of adverse events (Taxus® Express 2, Xience V®/Xience Prime® LL, Endeavor® Resolute, Nobori® – LRAE group), and those with a high rate of restenosis and thrombosis (IntrepideTM and Prolim® – HRAE group). The average cost of stents in the LRAE group was 2155.1 US dollars. Endovascular correction of in-stent restenosis were performed in 6.3% of cases, thrombosis – in 1.3%, the average direct treatment cost per patient over 12.7±1.6 months totaled 3906.4 US dollars. In the HRAE group the cheaper devices were implanted (median cost was $1650.8). Repeated PCIs due to restenosis were performed in 52.5% of cases, one patient (2.5%) with verified thrombosis underwent CABG. The average direct treatment cost per patient over 12.7±1.6 months period was 4993.5 US dollars, which was $1,087.1 more than in the LRAE group. Conclusion. The obtained data indicate higher financial cost during 12.7±1.6 months follow-up period after IntrepideTM and Prolim® stent implantation in the recanalized CTO areas. This emphasizes the impotance of using coronary stents with proven minimal risks of in-trastent restenosis and thrombosis in CTO cases.

Assessment of late gadolinium enhancement-negative chronic total occlusion by longitudinal strain analysis using cardiac magnetic resonance imaging

Strain analysis has become commonly used in clinical practice in various heart diseases. To explore whether late gadolinium enhancement (LGE)-negative areas with coronary artery chronic total occlusion (CTO) appear normal when analyzed for longitudinal strain using cardiac magnetic resonance (CMR) imaging. A total of 16 patients and 31 healthy controls who underwent 1.5-T MR at our hospital between January 2015 and July 2017 were included in the study. The LGE-CMR of patients with CTO was negative. Left ventricular functional parameters, segmental longitudinal strain/strain rate, and perfusion parameters were measured using CVI42 software. For myocardial segments supplied by CTO vessels, systolic longitudinal strain rate (SLSR)was significantly lower than that of healthy controls, and diastolic longitudinal strain rate (DLSR) was significantly higher (1.19 1/s vs. 1.02 1/s; P = 0.018). Moreover, longitudinal strain (LS), SLSR, and DLSR did not differ between good and poor collateral circulation. Perfusion index of CTO territory segments was lower than non-CTO territory segments (0.20 vs. 0.22; P = 0.027). No correlation was found between longitudinal strain parameters and perfusion parameters. Although LGE-CMR was negative in patients with CTO, the myocardial SLSR of CTO territory segments was significantly lower than that of healthy controls.

TCT-327 A Prospective, Randomized Trial of a Novel Localized Abluminal Groove With Low-Dose Sirolimus-Eluting and Biodegradable Polymer Stent Compared to a Durable Polymer-Based Everolimus-Eluting Stent in Patients With Coronary Artery Chronic Total Occlusions: The TARGET CTO Trial

TCT-327 A Prospective, Randomized Trial of a Novel Localized Abluminal Groove With Low-Dose Sirolimus-Eluting and Biodegradable Polymer Stent Compared to a Durable Polymer-Based Everolimus-Eluting Stent in Patients With Coronary Artery Chronic Total Occlusions: The TARGET CTO Trial