Collaterals and the recovery of left ventricular function after recanalization of a chronic total coronary occlusion

Association between hibernating myocardium and collateral circulation in patients with coronary chronic total occlusion

Objective

To explore the association between the quantity of hibernating myocardium (HM) and collateral circulation in patients with coronary chronic total occlusion (CTO).

Materials and methods

88 CTO patients were retrospectively analyzed who underwent evaluation for HM using both 99mTc-sestamibi Single photon emission computed tomography (99mTc-MIBI SPECT) myocardial perfusion imaging (MPI) combined with 18F-fluorodeoxyglucose positron emission tomography (18F-FDG PET) myocardial metabolism imaging (MMI). They were divided into two groups according Rentrop grading: the poorly/well-developed collateral circulation group (PD/WD group, Rentrop grades 0-1/2-3). After adjusting for the potential confounding factors and conducting a stratified analysis, we explored the association between the HM index within CTO region and the grading of collateral circulation.

Results

In the WD group, the HM index was notably higher than PD group (46.2 ± 15.7% vs. 20.9 ± 16.7%, P < 0.001). When dividing the HM index into tertiles and after adjusting for potential confounders, we observed that the proportion of patients with WD rose as the HM index increased (OR: 1.322, 95% CI: 0.893-1.750, P < 0.001), the proportion of patients with WD was 17.4%, 63.3%, and 88.6% for Tertile 1 to Tertile 3.This increasing trend was statistically significant (OR: 1.369, 95% CI: 0.873-1.864, P < 0.001), especially between Tertile 3 vs. Tertile 1 (OR: 4.330, 95% CI: 1.459-12.850, P = 0.008). Curve fitting displaying an almost linear positive correlation between the two.

Conclusion

The HM index within CTO region is an independent correlation factor for the grading of coronary collateral circulation. A greater HM index corresponded to an increased likelihood of WD.

Is it Worthy Enough to Revascularize Chronically Occluded Coronaries?

Chronic total occlusions (CTOs) represent the "final frontier" of coronary interventions with the lowest procedural success rates and the most common reason for incomplete revascularization and referral to coronary artery bypass graft surgery (CABG). CTO lesions are not an infrequent finding during coronary angiography. They are often responsible for enhancing the complexity of the coronary disease burden thereby affecting the final interventional decision in the process. Notwithstanding the modest technical success of CTO-PCI, most of the earlier observational data demonstrated a clear survival benefit free of major cardiovascular events (MACE) in patients undergoing successful CTO revascularization. However, data from recent randomized trials fail to uphold the same survival advantage albeit, showing some trend toward improvement in left ventricular function, quality of life indicators and freedom from fatal ventricular arrythmia. Various guidance statements propose a well-defined role for CTO intervention in specific situations provided criterions for patient selection, appreciable inducible ischemia, myocardial viability and cost-risk-benefit analysis are met.

Infarct-Related Artery as a Donor of Collaterals in ST-Segment-Elevation Myocardial Infarction With Concomitant Chronic Total Occlusion: Challenge of the Double-Jeopardy Thesis

BACKGROUND In ST-segment-elevation myocardial infarction (STEMI), a concomitant chronic total occlusion (CTO) in a non-infarct-related artery (NIRA) is associated with adverse outcome. In the case of the infarct-related artery (IRA) as a donor vessel for collaterals to the CTO, the IRA occlusion may lead to an acute threat to both the immediate IRA and the collaterally supplied CTO area, which has been described as a double-jeopardy effect. METHODS AND RESULTS We investigated the role of preformed intercoronary collaterals to the CTO originating from either the IRA or NIRA. Data were obtained from 2 hospitals participating in the prospective FITT-STEMI (Feedback Intervention and Treatment Times in ST-Segment Elevation Myocardial Infarction) study. From a total cohort of 2102 patients with acute STEMI, 93 patients had single-vessel CTO in an NIRA and well-developed intercoronary collaterals to the CTO. In-hospital mortality differed significantly with respect to the origin of the collaterals. Mortality was 15.2% with collaterals originating from the NIRA, 29.4% with a collateral origin from the IRA proximal to the acute STEMI occlusion, and 3.3% with a collateral origin from the IRA distal to the acute occlusion (P=0.044). A multivariate regression model confirmed that a proximal collateral origin had a significant higher mortality compared with a branching in the distal position from the acute STEMI occlusion (P=0.027; odds ratio = 20.8 [95% CI, 1.4-304.1]). CONCLUSIONS In STEMI with CTO in an NIRA, a CTO collateralization from the IRA distal to the acute occlusion is associated with a better prognosis. This finding challenges the double-jeopardy assumption as the main cause of adverse outcome in STEMI with CTO in an NIRA. REGISTRATION URL: https://www.clinicaltrials.gov; Unique identifier: NCT00794001.

Recanalisation of coronary chronic total occlusions

Percutaneous treatment of coronary chronic total occlusions (CTO) has advanced greatly since its advent in the late 1970s through the development of dedicated wires and microcatheters, the improved skills of highly experienced operators and the adoption of new sophisticated strategies to guide procedural planning. The contemporary procedural success rate is 80-90% with a reduction in complications. Although there has been no improvement in prognosis in randomised trials to date, they, and other controlled registries of thousands of patients, confirm the pivotal role of CTO recanalisation in the treatment of angina and dyspnoea and an improvement in quality of life. Despite this evidence, CTO recanalisation is grossly underutilised. This review reports a detailed overview of the history, indications and treatment strategies for CTO recanalisation and hopes to increase interest among new, and especially young, operators in this demanding, rapidly evolving field of interventional cardiology.

Integrated Analysis of Angiogenesis Related lncRNA-miRNA-mRNA in Patients With Coronary Chronic Total Occlusion Disease

Background: Coronary chronic total occlusion (CTO) disease is common and its specific characteristic is collateral formation. The Integrated analysis of angiogenesis related lncRNA-miRNA-mRNA network remains unclear and might provide target for future studies.

Methods: A total of five coronary artery disease (control group) and five CTO (CTO group) patients were selected for deep RNA and miRNA sequencing. The expression profiles of lncRNAs, mRNAs circRNA and miRNAs were obtained. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were then performed. The expression of a 14q32 miRNA gene cluster, including miRNA-494, miRNA-495 and miRNA-329, were selected to be determined in another larger patient cohort. Analysis of the lncRNA-miRNA495-mRNA network was constructed to find potential targets for future studies.

Results: A total of 871 lncRNAs, 1,080 mRNAs, 138 circRNAs and 56 miRNAs were determined as differentially expressed (DE) in CTO patients compared with control patients. GO and KEGG analyses revealed that the top terms included MAPK signaling pathway, HIF-1 signaling pathway, EGFR tyrosine kinase inhibitor resistance, embryonic organ development, wound healing, MAPK signaling pathway and JAK-STAT signaling pathway, which are related to angiogenesis. The expression of miRNA-494, miRNA-495 and miRNA-329 were all significantly down-regulated in CTO patients and they were confirmed to be down-regulated in another cohort of 68 patients. Then we divided the CTO patients into two groups according to CC grade (poor CC group, CC = 0 or one; good CC group, CC = 2). MiRNA-494, miRNA-495 and miRNA-329 were found to be down-regulated in good CC group compared with poor CC group. Analysis of the lncRNA-miRNA495-mRNA network showed 3 DE lncRNA sponges (NONHSAG008675, NONHSAG020957 and NONHSAG010989), 4 DE lncRNA targets (NONHSAT079547.2, NONHSAT081776.2, NONHSAT148555.1 and NONHSAT150928.1) and 2 DE mRNA targets (RAD54L2 and ZC3H4) of miRNA495.

Conclusion: This study revealed that the lncRNA-miRNA-mRNA network might play a critical role in angiogenesis in CTO patients.

Circulating Chromogranin B Is Associated With Left Ventricular Functional Recovery After Successful Recanalization of Chronic Total Occlusion

Background: Chromogranin B (CgB) is increased in heart failure and proportionate to disease severity. We investigated whether circulating CgB level is associated with left ventricular (LV) functional recovery potential after successful recanalization of chronic total occlusion (CTO). Methods: Serum levels of CgB were assayed in 53 patients with stable angina with LV functional recovery [an absolute increase in LV ejection fraction (EF) of ≥5%] and 53 age- and sex-matched non-recovery controls after successful recanalization of CTO during 12-month follow-up. Results: We found that CgB level was significantly lower in the recovery group than in the non-recovery group (593 [IQR 454-934] vs. 1,108 [IQR 696-2020] pg/ml, P < 0.001), and that it was inversely correlated with changes in LVEF (Spearman's r = -0.31, P = 0.001). Receiver operating characteristic (ROC) analysis showed that the area under the curve of CgB for predicting LVEF improvement was 0.76 (95% CI 0.664-0.856), and that the optimal cutoff value was 972.5 pg/ml. In multivariate analyses, after adjusting for confounding factors, high CgB level remained an independent determinant of impaired LV functional recovery after CTO recanalization. LV functional improvement appeared to be more responsive to CgB in patients with poor than with good coronary collaterals. Conclusions: Elevated circulating CgB level confers an increased risk of impaired LV functional recovery after successful recanalization of CTO in patients with stable coronary artery disease.

Preserved myocardial viability in patients with chronic total occlusion of a single coronary artery

OBJECTIVE

To assess the benefits of coronary collateral circulation on myocardial perfusion, viability and function in patients with total occlusion of a single coronary artery using the 99mTc-sestamibi SPECT and 18F-fluorodeoxyglucose PET.

METHODS

164 Consecutive patients were included who underwent coronary angiography results exhibited total occlusion of a single coronary artery and received 99mTc-MIBI SPECT and 18F-FDG PET within 90 days of angiography. Myocardial perfusion and viability in patients with collateral circulation and those without it were compared. Long-term follow-up was performed through a review of patient clinical records.

RESULTS

Collateral circulation was present in 56 patients (34%) and absent in 108 patients (66%). The total perfusion defect size in patients with collateral circulation decreased when compared to those without (30% ± 13% to 35% ± 14%, P < .05). The myocardial viability was 22% ± 12% in patients with collateral circulation, and 12% ± 9% in those without (P < .001). The left ventricular ejection fraction was higher, and the end-diastolic and end-systolic left ventricular volumes were lower in patients with collateral circulation (39% ± 11%, 138 ± 66, 89 ± 57) compared to patients without collateral circulation (31% ± 9%, 177 ± 55, 125 ± 48, all P < .001, respectively). Multi-factor logistic regression identified that concerning the variables of sex, age, viable myocardium, collateral circulation, treatment type and others, only treatment type was significantly associated with therapeutic effects (OR 3.872, 95% CI 1.915-7.830, P < .001).

CONCLUSION

Collateral circulation can preserve resting myocardial blood perfusion and myocardial viability, and help maintain the function of the left ventricular myocardium. The appropriate treatment strategy will have a substantial impact on the therapeutic outcome.

Long-term prognosis of chronic total occlusion treated by successful percutaneous coronary intervention in patients with or without diabetes mellitus: a systematic review and meta-analysis

Background

Diabetes mellitus (DM) is highly prevalent among patients undergoing percutaneous coronary intervention (PCI) for chronic total occlusion (CTO). Therefore, the purpose of our study was to investigate the clinical outcomes of CTO-PCI in patients with or without DM.

Methods

All relevant articles published in electronic databases (PubMed, Embase, and the Cochrane Library) from inception to August 7, 2020 were identified with a comprehensive literature search. Additionally, we defined major adverse cardiac events (MACEs) as the primary endpoint and used risk ratios (RRs) with 95% confidence intervals (CIs) to express the pooled effects in this meta-analysis.

Results

Eleven studies consisting of 4238 DM patients and 5609 non-DM patients were included in our meta-analysis. For DM patients, successful CTO-PCI was associated with a significantly lower risk of MACEs (RR = 0.67, 95% CI 0.55–0.82, p = 0.0001), all-cause death (RR = 0.46, 95% CI 0.38–0.56, p < 0.00001), and cardiac death (RR = 0.35, 95% CI 0.26–0.48, p < 0.00001) than CTO-medical treatment (MT) alone; however, this does not apply to non-DM patients. Subsequently, the subgroup analysis also obtained consistent conclusions. In addition, our study also revealed that non-DM patients may suffer less risk from MACEs (RR = 1.26, 95% CI 1.02–1.56, p = 0.03) than DM patients after successful CTO-PCI, especially in the subgroup with a follow-up period of less than 3 years (RR = 1.43, 95% CI 1.22–1.67, p < 0.0001).

Conclusions

Compared with CTO-MT alone, successful CTO-PCI was found to be related to a better long-term prognosis in DM patients but not in non-DM patients. However, compared with non-DM patients, the risk of MACEs may be higher in DM patients after successful CTO-PCI in the drug-eluting stent era, especially during a follow-up period shorter than 3 years.

Over Ten Years' Follow-Up of Chronic Total Coronary Occlusion Angioplasty

OBJECTIVES

It has been reported that successful percutaneous coronary intervention for chronic total occlusion (CTO-PCI) might be associated with symptom relief, a lower rate of subsequent myocardial infarction and coronary artery bypass graft surgery, and improved long-term survival, compared with unsuccessful PCI for CTO. However, the long-term benefit of percutaneous recanalization of CTO remains unclear. Therefore, we aimed to evaluate the long-term benefit of percutaneous recanalization of CTO.

METHODS

We analyzed consecutive cases of CTO-PCI performed between January 2000 and December 2006. The health status of all patients on September 2017 was obtained via letter or from medical records. We collected relevant patient information as well as angiographic and procedural characteristics.

RESULTS

A total of 477 patients (82.8% men, mean age, 65.7 years) underwent CTO-PCI. The procedural was successful in 382 cases (80.3%). Reference vessel diameter, occlusion length and angiographic stump of CTO site were associated with the success of CTO intervention. During the mean follow-up period of 139.8 months, successful CTO-PCI was associated with a higher survival rate when compared with failed CTO-PCI (Log-rank test: P = 0.0147). When categorized by target vessel, successful revascularization of left anterior descending (LAD) -CTO improved long-term survival (Log-rank test: P = 0.0041). On the other hand, successful revascularization of right coronary artery or left circumflex -CTO was not associated with improved long-term survival [Log-rank test: P = 0.5631 (RCA), P = 0.2774 (LCX)].

CONCLUSIONS

Successful CTO-PCI, especially the successful revascularization of LAD-CTO, improved long-term survival of patients.

Coronary collaterals and myocardial viability in patients with chronic total occlusions

AIMS

This study aimed to evaluate associations between coronary collaterals and myocardial viability as assessed by quantitative cardiac magnetic resonance (CMR) imaging in patients with a chronic coronary total occlusion (CTO).

METHODS AND RESULTS

A total of 218 patients with a CTO who underwent CMR between 2013 and 2018 were included. A concomitant collateral connection (CC) score 2 and Rentrop grade 3 defined well-developed collaterals in 146 (67%) patients, whereas lower CC scores or Rentrop grades characterised poorly developed collaterals. Dysfunctional myocardium (<3 mm segmental wall thickening [SWT]) and ≤50% late gadolinium enhancement (LGE) defined viability. Extensive scar (LGE >50%) was observed in only 5% of CTO segments. In the CTO territory, SWT was greater (3.72±1.51 vs 3.05±1.60 mm, p<0.01) and the extent of scar was less (7.0 [0.1-16.7] vs 13.1% [2.8-22.2], p=0.048) in patients having well-developed versus poorly developed collaterals. Viability was more prevalent in CTO segments among patients with poorly developed versus well-developed collaterals (44% vs 30% of segments, p<0.01), predominantly due to a higher prevalence of dysfunctional myocardium (51% vs 34% of segments, p<0.01) in the poorly developed collateral group.

CONCLUSIONS

The infarcted area in myocardium subtended by a CTO is generally limited. Well-developed collaterals are associated with less myocardial scar and enhanced preserved function. However, viability was regularly present in patients with poorly developed collaterals.

Multicenter experience with percutaneous coronary intervention for chronic total occlusion in Korean population: analysis of the Korean nationwide multicenter chronic total occlusion registry

OBJECTIVES

Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) remains challenging because of limited success and higher target vessel failure rates. Detailed safety and efficacy data for CTO-PCI from a multicenter real-world Korean registry are limited.

METHODS

Since May 2007, the Korean multicenter retrospective CTO registry has enrolled 3271 patients who underwent CTO-PCI at 26 major medical centers. Baseline clinical, angiographic, and procedural characteristics and 12-month major adverse cardiac event (MACE) rates after PCI were retrospectively collected.

RESULTS

Baseline cardiovascular risk factors included: male sex, 73.8%; prior myocardial infarction (MI), 14.8%; prior PCI, 26.6%; hypertension, 62.3%; diabetes mellitus, 34.8%; dyslipidemia, 33.3%; and current smoker, 30.9%. Pre-PCI myocardial viability testing was performed in 23.6% of patients and pre-PCI cardiac computed tomography (CT) in 17.6%. CTO arterial lesions were distributed as follows: right coronary, 41.0%; left anterior descending, 40.0%; left circumflex, 22.5%; and left main, 0.4%. Unfavorable lesion morphology was detected by angiography in 38.1%. Intravascular ultrasound guidance and the retrograde approach were utilized in 23.6 and 3.1% of CTO-PCI procedures, respectively. More than 75% of patients received drug-eluting stents (sirolimus-eluting, 26.5%; paclitaxel-eluting, 23.8%; zotarolimus-eluting, 23.4%; everolimus-eluting, 11.0%; and others, 4.0%). The overall success rate was 81.6% (2672/3271 patients). Twelve-month event rates were: total mortality, 2.4%; any MI, 0.7%; target lesion revascularization, 4.4%; target vessel revascularization, 6.7%; and total MACE, 9.4%.

CONCLUSIONS

Twelve-month success rates, safety profiles, and cumulative clinical outcomes of Korean CTO patients were favorable post-PCI. Long-term follow-up of larger study populations is necessary to validate our findings.

Relationship of myocardial hibernation, scar, and angiographic collateral flow in ischemic cardiomyopathy with coronary chronic total occlusion

BACKGROUND

The relationship between myocardial viability and angiographic collateral flow is not fully elucidated in ischemic cardiomyopathy (ICM) with coronary artery chronic total occlusion (CTO). We aimed to clarify the relationship between myocardial hibernation, myocardial scar, and angiographic collateral flow in these patients.

METHODS AND RESULTS

Seventy-one consecutive ICM patients with 122 CTOs and 652 dysfunctional segments within CTO territories were retrospectively analyzed. Myocardial hibernation (perfusion-metabolism mismatch) and the extent of 18F-fluorodeoxyglucose (FDG) abnormalities were assessed using 99mTc-sestamibi and 18F-FDG imaging. Myocardial scar was evaluated by late gadolinium enhancement (LGE) cardiac magnetic resonance (CMR) imaging. Collateral flow observed on coronary angiography was assessed using Rentrop classification. In these patients, neither the extent nor frequency of myocardial hibernation or scar was related to the status of collateral flow. Moreover, the matching rate in determining myocardial viability was poor between any 2 imaging indices. The extent of 18F-FDG abnormalities was linearly related to the extent of LGE rather than myocardial hibernation. Of note, nearly one-third (30.4%) of segments with transmural scar still had hibernating tissue. Hibernation and non-transmural scar had higher sensitivity (63.0% and 66.7%) than collateral flow (37.0%) in predicting global functional improvement.

CONCLUSIONS

Angiographic collateral cannot accurately predict myocardial viability, and has lower sensitivity in prediction of functional improvement in CTO territories in ICM patients. Hence, assessment of myocardial viability with non-invasive imaging modalities is of importance. Moreover, due to the lack of correlation between myocardial hibernation and scar, these two indices are complementary but not interchangeable.

Impact of diabetes mellitus on 5-year clinical outcomes in patients with chronic total occlusion lesions

BACKGROUND

Diabetes mellitus (DM) is a major predictor of cardiovascular morbidity and mortality. However, there are limited data on the impact of DM in patients who have chronic total occlusion (CTO) lesion on long-term outcomes.

PATIENTS AND METHODS

A total of 822 CTO patients who underwent coronary angiography, treated by either percutaneous coronary intervention or optimal medical therapy, were enrolled and divided into two groups: (i) diabetic group (n=363) and (ii) nondiabetic group (n=459). Individual and composite major clinical outcomes were compared up to 5 years.

RESULTS

Propensity score matching analysis was carried out generating two groups (298 pairs, n=596, C-statistic=0.655) with balanced baseline characteristics. Up to 5 years, the DM group showed a higher trend toward revascularization (19.5 vs. 13.5%, P=0.051) and major adverse cardiovascular events (MACE) (24.7 vs. 19.1%, P=0.097) compared with the nondiabetic group. However, there was no difference in the incidence of death and myocardial infarction between the two groups. Subgroup analysis showed that the chronic kidney disease (CKD) subgroup was associated with a higher incidence of all-cause death, cardiac death, myocardial infarction, revascularization, and MACE in comparison with diabetic patients without CKD and nondiabetic patients, respectively (total MACE: 39 vs. 20.5 vs. 19.2% , P=0.001). Insulin-dependent diabetic patients had a significantly higher incidence of MACE (hazard ratio=1.58; 95% confidence interval: 1.04-2.40; P=0.03) compared with the nondiabetic patients.

CONCLUSION

Diabetic patients with CTO were associated with a trend toward a higher incidence of revascularization and total MACE up to 5 years. Insulin-dependent and diabetic patients with CKD subgroups had a significantly higher incidence of total MACE.

Support with a twist: New approaches in CTOs and complex lesions

One-third of patients undergoing coronary angiography have coronary chronic total occlusions (CTOs) with the incidence increasing with age. Successful recanalization of a CTO is associated with a reduction in the future need for coronary artery bypass graft surgery (CABG), improvement in left ventricular function, and angina status as well as long-term survival. Success rates for treating CTOs with conventional techniques have remained unchanged over time averaging 65%-70% in experienced hands, well below the success rates for non-occlusive coronary lesions. The antegrade approach is utilized in standard balloon angioplasty. Modification of this technique has been used with an anchoring balloon to more successfully open up CTOs. We describe a new device that in addition to allowing increased support, also centers one in the lumen for both coronary and peripheral intervention. <Learning objective: Coronary total occlusions (CTOs) are the biggest reason patients are sent for coronary bypass when multi-vessel coronary disease is found. In most peripheral artery disease (PAD) patients, at least one peripheral vessel is 100% occluded. Current device designs have improved success rates in treating coronary and peripheral CTOs. The CrossLock™ catheter centers the lumen and gives better support to a chronically occluded vessel. The reader will find this device helpful in treating coronary and peripheral complex disease.>.

Impact of collateralisation to a concomitant chronic total occlusion in patients with ST-elevation myocardial infarction: a subanalysis of the EXPLORE randomised controlled trial

Objective

The impact on cardiac function of collaterals towards a concomitant chronic total coronary occlusion (CTO) in patients with ST-elevation myocardial infarction (STEMI) has not been investigated yet. Therefore, we have evaluated the impact of well-developed collaterals compared with poorly developed collaterals to a concomitant CTO in STEMI.

Methods and results

In the EXPLORE trial, patients with STEMI and a concomitant CTO were randomised to either CTO percutaneous coronary intervention (PCI) or no-CTO PCI. Collateral grades were scored angiographically using the Rentrop grade classification. Left ventricular ejection fraction (LVEF) and left ventricular end-diastolic volume (LVEDV) at 4 months were measured using cardiac magnetic resonance imaging. Well-developed collaterals (Rentrop grades 2-3) to the CTO were present in 162 (54%) patients; these patients had a significantly higher LVEF at 4 months (46.2±11.4% vs 42.1±12.7%, p=0.004) as well as a trend for a lower LVEDV (208.2±55.7 mL vs 222.6±68.5 mL, p=0.054) when compared with patients with poorly developed collaterals to the CTO. There was no significant difference in the total amount of scar in the two groups. Event rates were statistically comparable between patients with well-developed collaterals and poorly developed collaterals to the CTO at long-term follow-up.

Conclusions

In patients with STEMI and a concomitant CTO, the presence of well-developed collaterals to a concomitant CTO is associated with a better LVEF at 4 months. However, this effect on LVEF did not translate into improvement in clinical outcome. Therefore, the presence of well-developed collaterals is important, but should not solely guide in the clinical decision-making process regarding any additional revascularisation of a concomitant CTO in patients with STEMI.

Clinical trial registration

NTR1108.

Five-Year Outcomes of Successful Percutaneous Coronary Intervention with Drug-Eluting Stents versus Medical Therapy for Chronic Total Occlusions

PURPOSE

Many recent studies have reported that successful percutaneous coronary intervention (PCI) with drug-eluting stents (DESs) for chronic total occlusion (CTO) has more beneficial effects than failed CTO-PCI; however, there are only limited data available from comparisons of successful CTO-PCI with medical therapy (MT) in the Korean population.

MATERIALS AND METHODS

A total of 840 consecutive CTO patients who underwent diagnostic coronary angiography, receiving either PCI with DESs or MT, were enrolled. Patients were divided into two groups according to the treatment assigned. To adjust for potential confounders, propensity score matching (PSM) analysis was performed using logistic regression. Individual major clinical outcomes and major adverse cardiac events, a composite of total death, myocardial infarction (MI), stroke, and revascularization, were compared between the two groups up to 5 years.

RESULTS

After PSM, two propensity-matched groups (265 pairs, n=530) were generated, and the baseline characteristics were balanced. Although the PCI group showed a higher incidence of target lesion and vessel revascularization on CTO, the incidence of MI tended to be lower [hazard ratio (HR): 0.339, 95% confidence interval (CI): 0.110 to 1.043, p=0.059] and the composite of total death or MI was lower (HR: 0.454, 95% CI: 0.224 to 0.919, p=0.028), compared with the MT group up to 5 years.

CONCLUSION

In this study, successful CTO PCI with DESs was associated with a higher risk of repeat PCI for the target vessel, but showed a reduced incidence of death or MI.

Coronary chronic total occlusion intervention: utility or futility

INTRODUCTION

Despite an incidence of about 18-52% of the patients undergoing coronary angiography, chronic total occlusions (CTO) are rarely revascularised by percutaneous angioplasty (PCI). Nevertheless, current evidence suggests that successful CTO angioplasty improves symptoms, quality of life and long-term survival. During the last decade, the improvement of specific tools and techniques for these complex procedures, and the increasing experience of operators, have led to the achievement of success and complication rates almost equivalent to non-CTO angioplasty. Areas covered: This review focuses on the clinical benefits of CTO revascularization and on appropriate patient selection. Expert commentary: Current evidence suggests that successful CTO-PCI improves symptoms, quality of life and long-term survival. During the last years, the improvement of specific techniques for these complex procedures and the increasing experience of operators, have led to the achievement of success and complication rates almost equivalent to non-CTO lesion angioplasty.

Evaluation of Preprocedural Laboratory Parameters as Predictors of Drug-Eluting Stent Restenosis in Coronary Chronic Total Occlusion Lesions

This retrospective, single-center study assessed the prognostic value of several emerging inflammatory markers as predictors of in-stent restenosis (ISR) after drug-eluting stent implantation for coronary chronic total occlusion (CTO) lesions. Consecutive patients (n = 416) who underwent successful percutaneous coronary intervention (PCI) for documented CTO lesions and with follow-up angiography were enrolled. Preprocedural high-sensitivity C-reactive protein (hsCRP), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and red cell distribution width (RDW) were analyzed. At mean follow-up of 14.4 ± 3.3 months, ISR occurred in 72 patients. Compared with the non-ISR group, preprocedural hsCRP level, PLR, NLR, and RDW were significantly higher in the ISR group. The ISR group also had significantly greater proportions of patients with diabetes and smoking history, lower estimated glomerular filtration rate, higher low-density lipoprotein cholesterol (LDL-C) level and neutrophil count, longer stent length, and higher rate of severe dissection. In multivariate analysis, NLR (odds ratio [OR]: 3.110; 95% confidence interval [CI], 2.102-4.063; P < .001) and PLR (OR: 1.029; 95% CI, 1.016-1.143; P < .001) were independent predictors of ISR, along with LDL-C level and stent length. In conclusion, higher preprocedural NLR and PLR levels were independent risk factors for the development of ISR in patients who underwent PCI for CTO lesions.

Comparison of Benefit of Successful Percutaneous Coronary Intervention for Chronic Total Occlusion in Patients With Versus Without Reduced (≤40%) Left Ventricular Ejection Fraction

Successful recanalization of chronic total occlusions (CTO) has been associated with improved survival. Data on outcomes in patients with left ventricular (LV) systolic dysfunction undergoing percutaneous coronary intervention for CTO, however, are scarce. Between January 2005 and December 2013, a total of 2,002 consecutive patients undergoing elective CTO percutaneous coronary intervention at a tertiary care center were divided into patients with (LV ejection fraction ≤ 40%) and without (LV ejection fraction > 40%) LV systolic dysfunction as defined by transthoracic echocardiography. The primary end point was all-cause mortality. Median follow-up was 2.6 (1.1 to 3.1) years. A total of 348 (17.4%) patients had LV dysfunction. All-cause mortality was higher in patients with LV dysfunction (30.2%) than in those with normal LV function (8.2%, p <0.001), and associations remained significant after adjustment for baseline differences (adjusted hazard ratio [HR] 3.39, 95% confidence interval [CI] 2.57 to 4.47, p <0.001). Successful CTO recanalization was independently associated with reduced all-cause mortality, with similar relative risk reductions in both the preserved (6.6% vs 16.9%, adjusted HR 0.48, 95% CI 0.34 to 0.70, p <0.001) and the reduced LV function groups (26.2% vs 45.2%, adjusted HR 0.63, 95% CI 0.41 to 0.98, p = 0.04, interaction p = 0.28). In conclusion, irrespective of LV function, successful CTO recanalization is associated with a clear survival benefit.

Prognostic impact of chronic total coronary occlusion on long-term outcomes in implantable cardioverter-defibrillator recipients with ischaemic heart disease

Aims

The prognostic impact of chronic total coronary occlusion (CTO) on implantable cardioverter-defibrillator (ICD) recipients remains unclear.

Methods and results

Eighty-four consecutive patients with ischaemic heart disease who received ICD therapy for primary or secondary prevention were analysed. We investigated all-cause mortality and major adverse cardiac events (MACEs) including cardiac death, appropriate device therapy, hospitalization for heart failure, and ventricular assist device implantation. Of the study patients (mean age 70 ± 8 years; 86% men), 34 (40%) had CTO. There were no significant differences in age, left ventricular ejection fraction (LVEF), New York Heart Association functional class III or IV status, and proportion who underwent secondary prevention between patients with CTO (CTO group) and without CTO (non-CTO group). During a median follow-up of 3.8 years (interquartile range 2.7-5.4 years), the CTO group tended to have a higher MACE rate (log-rank P = 0.054) than the non-CTO group. Within the CTO group, there was no difference in the MACE rate between patients with and without viable myocardium. In patients with ICD for secondary prevention (n = 47), 16 patients (34%) with CTO had a higher MACE rate than patients without CTO (log-rank P < 0.01). Cox proportional hazards regression analysis showed that the presence of CTO, but not LVEF, was associated with a higher MACE rate. Multivariate analysis showed that the presence of CTO was a predictor of MACE (P < 0.05).

Conclusion

In patients with ischaemic heart disease receiving ICD implantation, the presence of CTO has an adverse impact on long-term prognosis, especially as secondary prevention.

Long-term clinical outcomes of successful revascularization with drug-eluting stents for chronic total occlusions: A systematic review and meta-analysis

OBJECTIVES

To determine whether successful percutaneous coronary intervention (PCI) using drug-eluting stents (DESs) have beneficial effects on long-term outcomes in patients with chronic total occlusions (CTOs) compared with failed PCIs for CTOs.

BACKGROUND

Several observational studies have evaluated the long-term clinical outcomes of successful PCIs using DESs for CTOs. However, the results of these studies were inconsistent and inconclusive.

METHODS

We searched five online electronic databases to identify all the publications assessing the long-term outcomes of successful and failed PCIs using DESs for CTOs. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated by STATA software.

RESULTS

A total of nine studies involving 5958 CTO patients who underwent successful PCI and 1511 CTO patients who underwent failed PCI were included in this meta-analysis. The results of the analysis indicated that successful CTO PCIs using DESs were associated with lower long-term all-cause mortality(OR = 0.55, 95% CI = 0.45-0.67, P < 0.001), lower risk of myocardial infarction (OR = 0.45, 95% CI = 0.23-0.74, P = 0.002), lower risk of major adverse cardiac events (MACEs, OR = 0.44, 95% CI = 0.27-0.72, P = 0.001), and less incidence of subsequent coronary artery bypass grafting (OR = 0.10, 95% CI = 0.05-0.21, P < 0.001) than failed CTO PCIs. However, there was no difference in the incidence of target vessel revascularization (OR = 1.06, 95% CI = 0.17-6.60, P > 0.05) between the two groups.

CONCLUSION

Successful CTO PCI using DESs can reduce long-term all-cause mortality and the risks of MI, MACEs, and CABG in patients with CTOs. © 2017 Wiley Periodicals, Inc.

Impact of Neutrophil to Lymphocyte Ratio (NLR) Index and Its Periprocedural Change (NLRΔ) for Percutaneous Coronary Intervention in Patients With Chronic Total Occlusion

We assessed the association between neutrophil to lymphocyte ratio (NLR) and chronic coronary total occlusion (CTO), as well as clinical prognosis of percutaneous coronary intervention (PCI). Patients referred for elective coronary angiography for stable angina pectoris were enrolled, including a CTO (n = 160) and a non-CTO group (n = 160). Neutrophil to lymphocyte ratio on admission and post-PCI was measured, and NLR_Δ was defined as the change between the 2 values. Subgroup analysis was performed based on the value of NLR_Δ (≥0.5 vs <0.5). Clinical characteristics, angiographic data, and follow-up data were recorded. Compared with the non-CTO group, the total white blood cell count, neutrophil counts, and NLR were significantly higher in the CTO group. In the NLR_Δ ≥ 0.5 subgroup, the incidence of severe dissection, slow coronary flow, in-stent restenosis (ISR), and major adverse cardiac events (MACEs) was obviously higher. In multivariate analysis, NLR_Δ was independently and positively associated with higher risks of ISR and MACE. The NLR could be a potential predictor of CTO, and NLR_Δ is independently associated with the adverse clinical outcomes in patients who underwent PCI.

The collateral circulation of coronary chronic total occlusions

AIMS

Despite advances in understanding the physiological role of collaterals in coronary chronic total occlusions (CTOs), collateral anatomy remains poorly defined. Our aim was to define the anatomy and interventional utility of collaterals within a large population of patients with CTOs.

METHODS AND RESULTS

We studied the coronary angiograms of 481 patients with 519 CTOs at six centres in the U.K. over four years. Detailed angiographic analysis was performed by interventional cardiologists specialising in CTO percutaneous coronary intervention (PCI). All visible collaterals with a collateral connection (CC) grade ≥1 were recorded. A subgroup of CTOs (n=277) was assessed for interventional capability, defined as whether the collateral supply was able to facilitate retrograde access. We described 45 different collateral patterns: 20 in right coronary artery (RCA), 13 in left anterior descending (LAD), and 12 in circumflex artery CTOs. Septal collaterals from the LAD to the right posterior descending artery (RPDA), and from the posterior descending artery to the LAD were most common, and most often considered as having "interventional capability".

CONCLUSIONS

This is the largest analysis of collateral circulation anatomy in a population of patients with CTOs. We anticipate that these data will be of significant benefit in angiographic analysis and procedure planning for CTO PCI.

Update on Coronary Chronic Total Occlusion Percutaneous Coronary Intervention

Chronic total occlusion (CTO) percutaneous coronary intervention (PCI) has significantly evolved during recent years. High success rates are being achieved by experienced centers and operators, but not at less-experienced centers. Use of CTO crossing algorithms can help improve the success and efficiency of these potentially lengthy procedures. There is a paucity of clinical trial data examining clinical outcomes of CTO PCI, which is critical for further adoption and refinement of the procedure. We provide a detailed overview of the clinical evidence and current available crossing strategies, with emphasis on recent developments and techniques.

Theory and practical based approach to chronic total occlusions

Coronary chronic total occlusions (CTOs) represent the most technically challenging lesion subset that interventional cardiologists face. CTOs are identified in up to one third of patients referred for coronary angiography and remain seriously undertreated with percutaneous techniques. The complexity of these procedures and the suboptimal success rates over a long period of time, along with the perception that CTOs are lesions with limited scope for recanalization, account for the underutilization of CTO Percutaneous Coronary Intervention (PCI). During the last years, dedicated groups of experts in Japan, Europe and United States fostered the development and standardization of modern CTO recanalization techniques, achieving success rates far beyond 90%, while coping with lesions of increasing complexity. Numerous studies support the rationale of CTO revascularization following documentation of viability and ischemia in the territory distal to the CTO. Successful CTO PCI provide better tolerance in case of future acute coronary syndromes and can significantly improve angina and left ventricular function. Randomized trials are on the way to further explore the prognostic benefit of CTO revascularization. The following review reports on the theory and the most recent advances in the field of CTO recanalization, in an attempt to promote a more balanced approach in patients with chronically occluded coronary arteries.

The evidence base for revascularisation of chronic total occlusions

When patients with ischaemic heart disease are considered for revascularisation the Heart Team's aim is to choose a therapy that will provide complete relief of angina for an acceptable procedural risk. Complete functional revascularisation of ischaemic myocardium is thus the goal and for this reason the presence of a chronic total occlusion (CTO) - which remain the most technically challenging lesions to revascularise percutaneously - is the most common reason for selecting coronary artery bypass surgery. From the behaviour of Heart Teams it is clear that physicians believe that CTOs are important. Yet when faced with patients with CTOs for whom surgery appears excessive (e.g. nonproximal LAD) or too high risk, there remains a reluctance to undertake CTO PCI, despite significant recent advances in procedural success and safety and a considerable body of evidence supporting a survival benefit following successful CTO PCI. This article reviews the relationship between CTOs, symptoms of angina, ischaemia and left ventricular dysfunction and further explores the evidence relating their treatment to improved quality of life and prognosis in patients with these features.

Physiologic significance of coronary collaterals in chronic total occlusions

Chronic total occlusions (CTOs) are commonly found in patients with coronary artery disease, and a system of collateral connections are found in almost all of these patients. These collateral vessels serve to prevent myocardial necrosis but are not sufficient to prevent myocardial ischemia during exercise. Unfortunately, the presence of well-developed collaterals has been used as argument against CTO revascularization. Many continue to falsely believe that these patients are "protected" by collaterals and, therefore, CTO recanalization is not indicated. Our knowledge of the physiologic significance of coronary collaterals has increased significantly over the past several years. Studies utilizing coronary pressure and flow velocity have answered a number of basic physiologic questions. We therefore sought to review the evidence for coronary collateral flow and their clinical significance in patients with CTOs.

Chronic total occlusions - Current techniques and future directions

Chronic total occlusions (CTOs) of coronary arteries represent a common and significant challenge to interventional cardiology. Medical therapy is often regarded as an adequate long term strategy in the management of these lesions with surgical intervention for refractory symptoms. Extensive collateralisation is used as a marker of distal coronary perfusion, further reinforcing non-invasive strategies. This together with relatively low percutaneous success rates outside of specialised centres has meant that rates of percutaneous intervention have remained low. Increasing evidence suggests that CTOs are not a benign entity. Further, symptom control and quality of life improve significantly with successful percutaneous revascularisation. Both factors have reignited interest in percutaneous modalities. The Japanese have been pioneers in the field of CTO intervention although their success rates have been difficult to replicate. New techniques and equipment developed in North America offer an alternative to the Japanese approach. These techniques focus on time, radiation and contrast minimisation. This review will assess the histopathology of CTO and shifting paradigms in CTO treatment strategies.

•

Chronic total occlusions are common and prognostically important.

•

Strategies for chronic occlusions are pioneered by Japanese, adapted by North American operators.

•

Japanese and North American strategies appear divergent, both add considerable expertise.

Lumen enlargement of the coronary segments located distal to chronic total occlusions successfully treated with drug-eluting stents at follow-up

AIMS

Chronic total occlusions (CTO) are the final stage of atherosclerosis. Occluded coronary arteries have large plaque burden and negative remodelling. The aim of this study was to assess lumen and vessel changes of segments located distal to successfully recanalised CTO.

METHODS AND RESULTS

Ninety-one CTO treated with drug-eluting stents underwent quantitative coronary angiography (QCA) at baseline and at 12-18 months; 31 underwent serial intravascular ultrasound (IVUS) imaging. Angiographic changes were assessed with QCA as differences in minimal, mean and maximal lumen diameter (MinLD, MeanLD and MaxLD, respectively). Vessel changes were assessed with IVUS as changes in plaque and vessel volume. At follow-up, angiographic MinLD increased 23.9% (from 0.88±0.32 to 1.09±0.35 mm; p<0.01), MeanLD 16.4% (from 1.59±0.44 to 1.85±0.45 mm; p<0.01) and MaxLD 11.7% (from 2.39±0.67 to 2.67±0.70 mm; p<0.01). Lumen enlargement was greater in non-restenotic lesions, small lumen area at the end of the index procedure and low LDL-cholesterol levels during the study. By IVUS, lumen volume increased 26.9% (from 108.1±89.2 to 137.3±115.3 mm3; p<0.01), vessel volume increased 12.1% (from 207.1±170.2 to 232.2±196.0 mm3; p<0.01) and plaque volume tended to decrease 3.9% (from 98.9±88.7 to 94.9±89.3 mm3; p=0.07). Small lumen at baseline was related to greater lumen enlargement.

CONCLUSIONS

Segments distal to recanalised CTO showed a notable lumen and vessel enlargement with a trend toward mild plaque regression. Low LDL-cholesterol levels increase lumen enlargement.

The age, creatinine, and ejection fraction score to risk stratify patients who underwent percutaneous coronary intervention of coronary chronic total occlusion

Age, creatinine, and ejection fraction (ACEF) score predict clinical outcomes in patients who underwent elective percutaneous coronary intervention (PCI) of nonocclusive coronary stenoses. We aimed at assessing the prognostic value of the ACEF score in patients who underwent successful PCI of chronic total occlusion (CTO). ACEF score was calculated in 587 patients treated with PCI of CTO: successful in 433 (74%; success group) and failed in 154 patients (26%; failure group). Patients were divided in ACEF tertiles: first <0.950, second from 0.950 to 1.207, and third ACEF tertile >1.207. Major adverse cardiac events (MACE = overall death + nonfatal myocardial infarction + clinically driven target vessel revascularization) were assessed in 558 patients (95%) up to 24 months (8 to 24 months). In success group, higher MACE rate was significantly associated with increasing ACEF tertile (first = 7%, second = 13%, third ACEF = 18%, p = 0.02). MACE-free survival was significantly decreased with increasing ACEF tertile (log-rank 5.58, p = 0.018). In the failure group, lower MACE rate was significantly associated with increasing ACEF tertile (p = 0.041). This was mainly driven by significant decreasing rate of target vessel revascularization along the tertiles (first = 34%, second = 19%, third ACEF = 10%, p = 0.007). Compared with success group, in failure group, MACE rate was significantly higher in the first tertile (p <0.001) and similar in the third tertile (p = 0.59). In conclusion, ACEF score represents a simple tool in the prognostication of patients successfully treated with PCI of CTO and identifies those patients who would not derive any significant clinical harm despite failed percutaneous revascularization of the CTO.