Ventricular Arrhythmias Among Implantable Cardioverter-Defibrillator Recipients for Primary Prevention

Completeness of Revascularization as a Determinant of Outcome: A Contemporary Review and Clinical Perspectives

It has been debated whether patients with multivessel coronary artery disease should undergo complete revascularization (CR). The benefit of CR is biologically plausible, and numerous studies and large meta-analyses suggested that CR achievement was associated with a substantial reduction of mortality and future coronary events. In patients with multivessel coronary artery disease, the aim of myocardial revascularization is to minimize residual ischemia. Therefore, CR of all significant coronary lesions has been proposed as the first priority in decision-making for myocardial revascularization between coronary artery bypass grafting and percutaneous coronary intervention (PCI). Reflecting the contemporary practice of ischemia-based revascularization, a physiological/functional approach, such as measurement of fractional flow reserve or instantaneous wave-free ratio, is considered more reasonable and should be encouraged for appropriate CR. In patients who present with acute ST-elevation myocardial infarction, current evidence suggests that an immediate or staged CR strategy might be equivalent or superior to culprit-only revascularization. There is still uncertainty on when and how to perform CR in ST-elevation myocardial infarction patients; comprehensive studies dedicated to this issue are required. Hybrid coronary revascularization includes the advantages of minimally invasive bypass grafting for the left anterior descending artery and PCI for non-left anterior descending arteries and has been proposed as a viable alternative for coronary artery bypass grafting or PCI only for achieving CR. In clinical practice, the extent of revascularization and strategy for CR should be individualized, taking account of different aspects of the patients, lesions, and treating physicians. Collaboration of coronary heart teams would confer balanced decision-making and advanced therapeutic capabilities.

Optimal medical therapy vs. coronary revascularization for patients presenting with chronic total occlusion: A meta-analysis of randomized controlled trials and propensity score adjusted studies

INTRODUCTION

The optimal management of patients with coronary chronic total occlusions (CTO) remains controversial. This meta-analysis aims to compare percutaneous coronary intervention of CTO (CTO-PCI) versus optimal medical therapy (OMT) in CTO patients.

METHODS

A literature search with highly specific terms was conducted using MEDLINE, EMBASE, and Web of Science to identify most relevant randomized controlled trials (RCTs) and observational studies with propensity score matching (PSM) evaluating differences in between CTO-PCI versus OMT. The primary endpoint was the incidence of major adverse cardiac events (MACEs, composite of cardiovascular death, acute coronary syndrome, and repeat PCI, re-PCI) while its single components were defined as secondary endpoints.

RESULTS

A total of eight studies was included, four RCTs and four PSMs. 3,971 patients were included in the analysis (2,050 CTO-PCI versus 1,921 OMT) with a mean follow-up of 3 years. No significant differences were found regarding overall MACE, re-PCI and AMI. Regarding CV-death, CTO-PCI was associated with a better outcome compared with OMT driven by PSMs (OR 0.52, 0.0.81, P < 0.01).

CONCLUSIONS

As compared to OMT, CTO-PCI was associated with similar MACE rate; however, CTO-PCI may be associated with reduced CV death, mainly due to PSMs effect.

A step-by-step guide to mastering retrograde coronary chronic total occlusion intervention in 2018: The author's perspective

Chronic total occlusion remains one of the most challenging subsets and represents the "last frontier" of percutaneous coronary intervention. Retrograde recanalization is one of the most significant amendments of the technique and has become an important complement to the classical antegrade approach. It yields a high success rate even in most complex patients. With emergence of important iterations, this approach has become safer, faster, and more successful. The author proposes a step-by-step guide to the retrograde approach with alternatives to various steps for operators wishing to embark on this strategy.

The effect of revascularization of a chronic total coronary occlusion on electrocardiographic variables. A sub-study of the EXPLORE trial

INTRODUCTION

Chronic total coronary occlusions (CTOs) have been associated with a higher prevalence of ventricular arrhythmias compared to patients without a CTO. We evaluated the effect of CTO revascularization on electrocardiographic (ECG) variables.

METHODS

We studied a selection of ST-elevation myocardial infarction patients with a concomitant CTO enrolled in the EXPLORE trial. ECG variables and cardiac function were analysed at baseline and at 4 months follow-up.

RESULTS

Patients were randomized to percutaneous coronary intervention (PCI) of their CTO (n = 77) or to no-CTO PCI (n = 81). At follow-up, median QT dispersion was significantly lower in the CTO PCI group compared to the no-CTO PCI group (46 ms [33-58] vs. 54 ms [37-68], P = 0.043). No independent association was observed between ECG variables and cardiac function.

CONCLUSION

Revascularization of a CTO after STEMI significantly shortened QT dispersion at 4 months follow-up. These findings support the hypothesis that CTO revascularization reduces the pro-arrhythmic substrate in CTO patients.

Impact of Coronary Artery Chronic Total Occlusion on Arrhythmic and Mortality Outcomes: A Systematic Review and Meta-Analysis

OBJECTIVES

This study aimed to examine the relationship between chronic coronary artery total occlusion (CTO) status and the occurrence of ventricular tachycardia (VT)/ventricular fibrillation (VF) or appropriate implantable cardioverter-defibrillator (ICD) therapy.

BACKGROUND

CTO is a significant problem in patients with ischemic heart disease. However, the extent to which it predisposes affected individuals to VT/VF and whether these arrhythmic events could be prevented by revascularization are unclear. Therefore, a systematic review and meta-analysis were conducted to examine the relationship between CTO status and the occurrence of VT/VF or appropriate ICD therapy.

METHODS

PubMed and Embase databases were searched until November 16, 2017, identifying 137 studies.

RESULTS

Seventeen studies involving 54,594 subjects (mean age, 61 ± 21 years of age, 81% male) with a mean follow-up of 43 ± 31 months were included. The presence of CTO was associated with higher risk of VT/VF or appropriate ICD therapy (adjusted hazard ratio [aHR]: 1.99; 95% confidence interval (CI): 1.53 to 2.59; p < 0.0001, I² = 3%) but not in cardiac mortality (aHR: 2.59; 95% CI: 0.64 to 10.59; p = 0.18, I² = 86%) or in all-cause mortality (aHR: 1.70; 95% CI: 0.84 to 3.46; p = 0.14; I² = 64%). Compared to patients with non-infarct-related CTOs, those with infarct-related CTOs have a higher risk of VT/VF or appropriate ICD therapy (aHR: 2.47; 95% CI: 1.76 to 3.46; p < 0.0001; I² = 14%), cardiac mortality (aHR: 2.73; 95% CI: 1.02 to 7.30; p < 0.05; I² = 79%) and higher all-cause mortality (aHR: 1.69; 95% CI: 1.19 to 2.40; p < 0.01; I² = 40%). Nonrevascularization of CTOs tended to be associated with an increased risk of all-cause mortality compared to successful revascularization (unadjusted HR: 1.52; 95% CI: 0.96 to 2.43; p = 0.08; I² = 76).

CONCLUSIONS

CTOs, especially infarct-related, are associated with high risk of VT/VF or appropriate ICD therapy and mortality. ICD implantation could be beneficial. However, it is not clear that revascularization has an impact on the outcome of patients with CTOs.

Prognostic impact of non-culprit chronic total occlusions in infarct-related cardiogenic shock: results of the randomised IABP-SHOCK II trial

AIMS

The aim of the current study was to investigate the impact of a chronic total occlusion (CTO) in a non-infarct-related coronary artery (non-IRA) on one-year mortality and occurrence of cardiac arrhythmia in patients with cardiogenic shock (CS) complicating acute myocardial infarction (AMI).

METHODS AND RESULTS

In a retrospective sub-analysis of the Intraaortic Balloon Pump in Cardiogenic Shock II trial (IABP-SHOCK II) and its accompanying registry, 201 (26%) of 761 patients had a CTO in a non-IR major coronary artery. Mortality was significantly higher in the CTO group at day of admission (19% vs. 11%; p=0.005), 30 days (53% vs. 41%, p=0.002), and 12 months (63% vs. 51%, p=0.002). In the adjusted multivariate Cox regression analysis, a CTO in a non-IRA was an independent predictor of mortality at 12 months (hazard ratio 1.30, 95% confidence interval [CI]: 1.02-1.67, p=0.03). At 30-day follow-up, ventricular arrhythmias requiring defibrillation occurred more frequently in patients with non-IRA CTO in the univariate analysis (33% vs. 21%, odds ratio 1.83, 95% CI: 1.28-2.62, p=0.002).

CONCLUSIONS

In patients with CS complicating AMI, the presence of CTO in a non-IRA is associated with a higher incidence of ventricular arrhythmias and is an independent predictor of mortality at 12-month follow-up.

Meta-Analysis of Risk of Ventricular Arrhythmias and All-Cause Mortality in Patients With Chronic Total Occlusion of a Coronary Artery and/or Implantable Cardioverter-Defibrillator

Implantable cardioverter-defibrillator (ICD) has been increasingly used to prevent sudden death in patients with high risk of ventricular arrhythmias (VAs). Chronic total occlusion (CTO) is a severe condition of coronary artery disease. However, the prognostic impact of CTO in ICD recipients remains controversial. We systematically searched the PubMed, EMBASE, and Cochrane databases for documents published before October 1, 2017 to identify studies that investigated the prognostic impact of CTO on VAs and all-cause mortality (ACM) in ICD recipients. The effect size was expressed by hazard ratio (HR) and 95% confidence interval (CI). Overall, 6 studies with 1,423 patients were included. We found that CTO independently predicted the occurrence of VAs in the global population (HR 1.77, 95% CI 1.14 to 2.76, p = 0.01). Subgroup analysis revealed that CTO only predicted VAs in patients receiving ICD as secondary prevention (HR 1.96, 95% CI 1.55 to 2.48, p <0.01). However, CTO was not associated with ACM in the global population (HR 1.51, 95% CI 0.99 to 2.32, p = 0.06). Further subgroup analysis still showed no association between CTO and ACM in patients receiving ICD as primary prevention (HR 1.49, 95% CI 0.43 to 5.21, p = 0.53) or secondary prevention (HR 1.56, 95% CI 0.87 to 2.78, p = 0.13). In conclusion, CTO is an independent predictor of VAs in patients with secondary-prevention ICD, but not for ACM. Our study provided additional evidence for improving the risk stratification and management of VAs in ICD recipients.

Evaluation of the Impact of a Chronic Total Coronary Occlusion on Ventricular Arrhythmias and Long-Term Mortality in Patients With Ischemic Cardiomyopathy and an Implantable Cardioverter-Defibrillator (the eCTOpy-in-ICD Study)

Background

Previous studies report conflicting results about a higher incidence of ventricular arrhythmias in patients with a chronic total coronary occlusion (CTO). We aimed to investigate this association in a large cohort of implantable cardioverter defibrillator patients with long‐term follow‐up.

Methods and Results

All consecutive patients from 1992 onwards who underwent implantable cardioverter defibrillator implantation for ischemic cardiomyopathy at the Leiden University Medical Center were evaluated. Coronary angiograms were reviewed for the presence of a CTO. The occurrence of ventricular arrhythmias and survival status at follow‐up were compared between patients with and patients without a CTO. A total of 722 patients constitute the study cohort (age 66±11 years; 84% males; 74% primary prevention, median left ventricular ejection fraction 30% [first–third quartile: 25–37], 44% received a cardiac resynchronization therapy defibrillator). At baseline, 240 patients (33%) had a CTO, and the CTOs were present for at least 44 (2–127) months. The median follow‐up duration was 4 (2–6) years. On long‐term follow‐up, CTO patients had a higher crude appropriate device therapy rate (37% versus 27%, P=0.010) and a lower crude survival rate (51% versus 67%, P<0.001) compared with patients without a CTO. Corrected for baseline characteristics including left ventricular ejection fraction, the presence of a CTO was an independent predictor for appropriate device therapy.

Conclusions

The presence of a CTO in implantable cardioverter defibrillator patients was associated with more appropriate device therapy and worse prognosis at long‐term follow‐up. Further investigation is warranted regarding a potential beneficial effect of CTO revascularization on the incidence of ventricular arrhythmias.

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.

Predictors of mortality and ICD shock therapy in primary prophylactic ICD patients-A systematic review and meta-analysis

Background

There is evidence that the benefit of a primary prophylactic ICD therapy is not equal in all patients.

Purpose

To evaluate risk factors of appropriate shocks and all- cause mortality in patients with a primary prophylactic ICD regarding contemporary studies.

Data source

PubMed, LIVIVO, Cochrane CENTRAL between 2010 and 2016.

Study selection

Studies were eligible if at least one of the endpoints of interest were reported.

Data extraction

All abstracts were independently reviewed by at least two authors. The full text of all selected studies was then analysed in detail.

Data synthesis

Our search strategy retrieved 608 abstracts. After exclusion of unsuitable studies, 36 papers with a total patient number of 47282 were included in our analysis. All-cause mortality was significantly associated with increasing age (HR 1.41, CI 1.29–1.53), left ventricular function (LVEF; HR 1.21, CI 1.14–1.29), ischemic cardiomyopathy (ICM; HR 1.37, CI 1.14–1.66) and co-morbidities such as impaired renal function (HR 2.30, CI 1.97–2.69). Although, younger age (HR 0.96, CI 0.85–1.09), impaired LVEF (HR 1.26, CI 0.89–1.78) and ischemic cardiomyopathy (HR 2.22, CI 0.83–5.93) were associated with a higher risk of appropriate shocks, none of these factors reached statistical significance.

Limitations

Individual patient data were not available for most studies.

Conclusion

In this meta-analysis of contemporary clinical studies, all-cause mortality is predicted by a variety of clinical characteristics including LVEF. On the other hand, the risk of appropriate shocks might be associated with impaired LVEF and ischemic cardiomyopathy. Further prospective studies are required to verify risk factors for appropriate shocks other than LVEF to help select appropriate patients for primary prophylactic ICD-therapy.

Prognostic Impact of Chronic Total Occlusions: A Report From SCAAR (Swedish Coronary Angiography and Angioplasty Registry)

OBJECTIVES

The aim of this study was to determine the prognostic impact of chronic total occlusion (CTO) on long-term mortality in a large prospective cohort.

BACKGROUND

CTO is present in many patients with coronary artery disease and is difficult to treat with percutaneous coronary intervention.

METHODS

The study population consisted of all consecutive patients who underwent coronary angiography in Sweden between January 1, 2005 and January 1, 2012, who were registered in SCAAR (Swedish Coronary Angiography and Angioplasty Registry). The patient population was heterogeneous with regard to indication for angiography (stable angina, ST-segment elevation myocardial infarction [STEMI], unstable angina or non-STEMI, and other) and treatment options. The long-term mortality rates of patients with and without CTO were compared by using shared frailty Cox proportional hazards regression adjusted for confounders. Tests were conducted for interactions between CTO and several pre-specified characteristics: indication for angiography and percutaneous coronary intervention (stable angina, STEMI, unstable angina or non-STEMI, and other), severity of coronary artery disease (1-, 2-, and 3-vessel and/or left main coronary artery disease), age, sex, and diabetes.

RESULTS

During the study period, 14,441 patients with CTO and 75,431 patients without CTO were registered in SCAAR. CTO was associated with higher mortality (hazard ratio: 1.29; 95% confidence interval: 1.22 to 1.37; p < 0.001). In subgroup analyses, the risk attributable to CTO was lowest in patients with stable angina and highest in those with STEMI. In addition, CTO was associated with highest risk in patients under 60 years of age and with lowest risk in octogenarians. There was no interaction between CTO and either diabetes or sex, suggesting an equally adverse effect in both groups.

CONCLUSIONS

In this large prospective observational study of patients with coronary artery disease, CTO was associated with increased mortality. This association was most prominent in younger patients and in those with acute coronary syndromes.

Contemporary Evidence, Treatment Strategies, and Indications for Chronic Total Occlusion-Percutaneous Coronary Intervention

Chronic total occlusions (CTOs) are detected incidentally in ˜20% of patients undergoing coronary angiography and are often associated with significant morbidity and mortality. CTOs can manifest with worsening symptoms, reduced left ventricular function, and increased incidence of ventricular arrhythmias. Despite this, according to USA, Italian, and Japanese national registry data, only ~5–22% of CTO lesions are treated by percutaneous coronary intervention (PCI). CTO-PCI is a particularly challenging technique for this subset of lesions and has traditionally been associated with increased risks and complications compared to conventional PCI. However, increased experience, the development of novel techniques, and dedicated equipment have revolutionised CTO-PCI. USA, Italian, and Japanese registry data have shown success rates of between 85% and 90%, with diminishing complication rates when performed by experienced operators. Moreover, observational studies have suggested that there are significant benefits of using CTO-PCI, including fewer symptoms, improved quality of life, reduced need for coronary artery bypass surgery, and reduction in ischaemic burden and mortality. In addition, when there is demonstrable ischaemia and viable myocardium in the CTO territory, there is further potential prognostic benefit from complete revascularisation. However, there has so far been a relative lack of randomised trial data to support the routine use of CTO-PCI. This paper reviews the current evidence surrounding this subject and discusses the arguments for and against CTO-PCI. It includes an exploration of the interventionalist’s ‘toolbox’ and the techniques used in CTO-PCI, including a section on ‘tips and tricks’ for the most challenging cases. Finally, there is a discussion on the future of CTO-PCI including promising ongoing clinical trials and novel equipment that may improve outcomes and help to establish a more widespread adoption of CTO-PCI.

Percutaneous coronary interventions of chronic total -occlusions; a review of clinical indications, treatment strategy and current practice

Chronic total occlusions (CTOs) are commonly encountered in patients undergoing coronary angiography, but percutaneous coronary intervention (PCI) for CTO is currently infrequently performed owing to the perception of limited clinical benefit, high complexity and cost of intervention, and perceived risk of complications. Numerous 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 remains debated. Nevertheless, over the past decade the interest in CTO-PCI has exponentially grown due to important developments in dedicated equipment and techniques, resulting in high success and low complication rates. A number of factors must be taken into consideration in selecting patients for CTO-PCI, including presence of symptoms attributable to the CTO, extent of ischaemia distal to the occlusion, and degree of myocardial viability. In this review, we focus on the impact of CTO revascularization on clinical outcomes and QOL and on appropriate patient selection. Data regarding efficacy and safety of recent advances in PCI-CTO techniques will be discussed. Steps involved in setting up a dedicated CTO program will be outlined and the current CTO landscape in Belgium will be briefly highlighted. The overall aim of this review is to promote a more balanced approach to management of patients with a CTO.

Improved recovery of regional left ventricular function after PCI of chronic total occlusion in STEMI patients: a cardiovascular magnetic resonance study of the randomized controlled EXPLORE trial

BACKGROUND

The Evaluating Xience and left ventricular function in PCI on occlusiOns afteR STEMI (EXPLORE) trial did not show a significant benefit of percutaneous coronary intervention (PCI) of the concurrent chronic total occlusion (CTO) in ST-segment elevation myocardial infarction (STEMI) patients on global left ventricular (LV) systolic function. However a possible treatment effect will be most pronounced in the CTO territory. Therefore, we aimed to study the effect of CTO PCI compared to no-CTO PCI on the recovery of regional LV function, particularly in the CTO territory.

METHODS

Using cardiovascular magnetic resonance (CMR) we studied 180 of the 302 EXPLORE patients with serial CMR (baseline and 4 months follow-up). Segmental wall thickening (SWT) was quantified on cine images by an independent core laboratory. Dysfunctional segments were defined as SWT < 45%. Dysfunctional segments were further analyzed by viability (transmural extent of infarction (TEI) ≤50%.). All outcomes were stratified for randomization treatment.

RESULTS

In the dysfunctional segments in the CTO territory recovery of SWT was better after CTO PCI compared to no-CTO PCI (ΔSWT 17 ± 27% vs 11 ± 23%, p = 0.03). This recovery was most pronounced in the dysfunctional but viable segments(TEI < 50%) (ΔSWT 17 ± 27% vs 11 ± 22%, p = 0.02). Furthermore in the CTO territory, recovery of SWT was significantly better in the dysfunctional segments in patients with Rentrop grade 2-3 collaterals compared to grade 0-1 collaterals to the CTO (16 ± 26% versus 11 ± 24%, p = 0.04).

CONCLUSION

CTO PCI compared with no-CTO PCI is associated with a greater recovery of regional systolic function in the CTO territory, especially in the dysfunctional but viable segments. Further research is needed to evaluate the use of CMR in selecting post-STEMI patients for CTO PCI and the effect of regional LV function recovery on clinical outcome.

TRIAL REGISTRATION

Trialregister.nl NTR1108 , Date registered NTR: 30-okt-2007.

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.

"Spiral stenting"-creating a subintimal neo-luminal helix around a massively calcified ostial chronic total occlusion of the right coronary artery in a patient with recurrent ventricular tachycardia

This case report describes a successful percutaneous coronary intervention (PCI) of a severely calcified aorto-ostial chronic total occlusion (CTO) of the right coronary artery (RCA). The lesion was treated by a retrograde approach implementing long spiral subintimal wire tracking and final coronary stenting creating a subintimal neo-luminal helix around the natively occluded RCA. After 6 months of follow-up valuable angiographic results were proven.

[Chronic coronary occlusions : When and how should revascularization be performed?]

Chronic occlusion of coronary arteries also known as chronic total occlusions (CTO) are found in approximately 20 % of patients undergoing percutaneous coronary interventions (PCI) and in approximately 50 % of patients after coronary artery bypass grafts (CABG). As a result of technical advancements in retrograde recanalization techniques specialized centers can now achieve success rates of over 85 %, regardless of the CTO anatomy. Given the complexity of retrograde CTO techniques, a consensus paper issued by the Euro CTO Club requires interventional cardiologists to have sufficient experience in antegrade approaches (>300 antegrade CTO cases and >50 per year) with an additional training program (25 retrograde cases each as first and second operating surgeon) before becoming a qualified independent retrograde surgeon. The increased investment in time and technical resources can only be justified if the patient has a clear clinical benefit. This technical advancement and the progressively clearer evidence that complete revascularization can be achieved in patients with multivessel coronary artery disease have attracted growing interest in recent years from interventional cardiologists in the recanalization of CTO.

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.

Myths to Debunk to Improve Management, Referral, and Outcomes in Patients With Chronic Total Occlusion of an Epicardial Coronary Artery

A chronic total occlusion (CTO) is defined as an occlusive (100% stenosis) coronary lesion with anterograde Thrombolysis In Myocardial Infarction 0 flow for at least 3 months. CTOs are common in patients referred for coronary angiography (up to 33%) and are associated with angina, impaired quality of life, and reduced survival. Unfortunately, CTO percutaneous coronary intervention continues to be underperformed worldwide (10% to 15% at most institutions, ∼30% where expert operators are available). The aim of this study was to address common fallacies pertaining to CTOs among cardiologists by providing a concise review of pertinent previously published reports along with an update on safety and efficacy of state-of-the-art CTO percutaneous coronary intervention techniques.

Impact of Chronic Total Occlusions and Coronary Revascularization on All-Cause Mortality and the Incidence of Ventricular Arrhythmias in Patients With Ischemic Cardiomyopathy

Coronary chronic total occlusions (CTOs) have been associated with higher mortality in patients with ischemic cardiomyopathy and implantable cardioverter defibrillators (ICDs); yet the impact of CTO revascularization on subsequent clinical outcomes has not been studied. We evaluated the clinical characteristics and outcomes of patients with ischemic cardiomyopathy who also received an ICD for primary prevention of sudden death at the Dallas VA Medical Center from January 2002 to December 2013. On the basis of coronary angiography performed before device implantation, patients were divided into 3 groups: no CTOs, revascularized CTOs (with percutaneous coronary intervention or surgery), and unrevascularized CTOs. Primary and secondary outcomes were all-cause mortality and appropriate ICD therapy for sustained ventricular arrhythmias. A total of 307 patients (mean age 64.3 ± 8.1 years, 100% men) were included in the study. At least 1 CTO was present in 213 patients (69%) and was revascularized in 99 patients (32%). During a median follow-up of 4.1 years, 51 patients (17%) died and 98 (32%) had at least 1 episode of sustained ventricular arrhythmia. Mortality and incidence of ventricular arrhythmias were similar in the 3 study groups in both univariate and multivariate analyses. In conclusion, CTOs are commonly found in patients with ischemic cardiomyopathy. In contrast to previous studies, the presence of a CTO was not associated with higher mortality or incidence of ventricular arrhythmias. In addition, revascularization of CTOs was not associated with improved outcomes in this high-risk cohort.

Impact of Magnesium L-Lactate on Occurrence of Ventricular Arrhythmias in Patients with Implantable Cardioverter Defibrillators: A Randomized, Placebo-Controlled Trial

Background:

We evaluated the antiarrhythmic efficacy and quality of life (QoL) impact of oral magnesium Llactate on patients with an implantable cardioverter defibrillator (ICD).

Methods:

This prospective, double-blind, placebo-controlled trial randomized 70 patients with an ICD to receive oral magnesium L-lactate 3 tablets twice daily (504mg elemental magnesium daily) or matching placebo for 12 months. Patients were seen at baseline, 12, 24, 36, and 52 weeks. The primary endpoints were the cumulative occurrence of ICD therapy [either shock or anti-tachycardia pacing (ATP)] or QoL between the groups.

Results:

Among the 70 randomized patients with a mean ± SD follow-up of 6.4 ± 4.1 months, 10 patients in the placebo group and 8 in the magnesium group experienced either ICD shock or ATP [HR 0.84, 95% CI 0.33 to 2.12; p=0.706]. Without significant arrhythmia suppression, only minimal effects on QoL were seen. Eighty six percent of all patients had serum intracellular magnesium deficiency.

Conclusion:

In our underpowered trial, patients with ICDs had intracellular magnesium deficiency but oral magnesium Llactate only nonsignificantly reduced the occurrence of ICD therapies and had little impact on HrQoL.

Meta-analysis of clinical outcomes of patients who underwent percutaneous coronary interventions for chronic total occlusions

Successful percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) has been associated with clinical benefit. There are no randomized controlled trials on long-term clinical outcomes after CTO PCI, limiting the available evidence to observational cohort studies. We sought to perform a weighted meta-analysis of the long-term outcomes of successful versus failed CTO PCI. A total of 25 studies, published from 1990 to 2014, with 28,486 patients (29,315 CTO PCI procedures) were included. We analyzed data on mortality, subsequent coronary artery bypass grafting (CABG), myocardial infarction, major adverse cardiac events, angina pectoris, stroke, and target vessel revascularization using random-effects models. Procedural success was 71% (range 51% to 87%). During a weighted mean follow-up of 3.11 years, compared with unsuccessful, successful CTO PCI was associated with lower mortality (odds ratio [OR] 0.52, 95% confidence interval [CI] 0.43 to 0.63), less residual angina (OR 0.38, 95% CI 0.24 to 0.60), lower risk for stroke (OR 0.72, 95% CI 0.60 to 0.88), less need for subsequent coronary artery bypass grafting (OR 0.18, 95% CI 0.14 to 0.22), and lower risk for major adverse cardiac events (0.59, 95% CI 0.44 to 0.79). There was no difference in the incidence of target vessel revascularization (OR 0.66, 95% CI 0.36 to 1.23) or myocardial infarction (OR 0.73, 95% CI 0.52 to 1.03). Outcomes were similar in patients who underwent balloon angioplasty only or stenting with bare metal or drug-eluting stents. Compared with failed procedures, successful CTO PCIs are associated with a lower risk of death, stroke, and coronary artery bypass grafting and less recurrent angina pectoris.

Ventricular tachycardic storm with a chronic total coronary artery occlusion treated with percutaneous coronary intervention

A 66-year-old man with a history of coronary artery disease was evaluated due to ventricular tachycardic (VT) storm. The patient continued to have frequent recurrences of VT despite treatment with amiodarone and lidocaine. Since the ventricular arrhythmia could be related to myocardial ischemia related to a chronic total occlusion (CTO) of the right coronary artery, the patient underwent successful percutaneous coronary intervention of the CTO, followed by implantable cardioverter defibrillator implantation. He had no further episodes of VT during his hospital stay. After 9 months of follow-up, he had no further chest pain or clinically apparent recurrent ischemia. Interrogation of his defibrillator has shown brief nonsustained episodes of ventricular tachycardia, but the patient has not required delivery of a shock. The temporal association between treatment of the CTO and resolution of the VT, as well as the lack of recurrence of sustained VT, suggest a causative link between underlying ischemia produced by a chronically occluded coronary artery and provocation of VT and lend supportive evidence to this treatment approach.

Meta-analysis on the impact of percutaneous coronary intervention of chronic total occlusions on left ventricular function and clinical outcome

BACKGROUND

Percutaneous coronary intervention (PCI) of chronic total occlusions (CTOs) may have a beneficial effect on survival through a better-preserved or improved LVEF. Current literature consists of small observational studies therefore we performed a weighted meta-analysis on the impact of revascularization of CTOs on left ventricular ejection fraction (LVEF), left ventricular end-diastolic volume (LVEDV) and long-term mortality.

METHODS

We conducted a meta-analysis evaluating LVEF before and after CTO PCI and long-term mortality. No language or time restrictions were applied. References from the identified articles and reviews were examined to find additional relevant manuscripts.

RESULTS

Of the 812 citations, 34 studies performed between 1987-2014 in 2243 patients were eligible for LVEF and 27 studies performed between 1990-2013 in 11,085 patients with success and 4347 patients that failed CTO PCI were eligible for long-term mortality. After successful CTO PCI, LVEF increased with 4.44% (95% CI: 3.52-5.35, p<0.01) compared to baseline. In a small cohort of ~70 patients, no significant difference in LVEF was observed after non-successful CTO PCI or reocclusion. Additionally, 8 studies reported the change in left ventricular end-diastolic volume (LVEDV) in a total of 412 patients. LVEDV decreased with 6.14 ml/m(2) (95% CI: -9.31 to -2.97, p<0.01). Successful CTO PCI was also associated with reduced mortality in comparison with failed CTO PCI (OR: 0.52, 95% CI: 0.43-0.62, p-value<0.01).

CONCLUSIONS

The current meta-analysis revealed that successful recanalization of a CTO resulted in an overall improvement of 4.44% absolute LVEF points, reduced adverse remodeling and an improvement of survival (OR: 0.52).

Impact of a chronic total occlusion in an infarct-related artery on the long-term outcome of ventricular tachycardia ablation

INTRODUCTION

In patients with a prior myocardial infarction (MI), angiographic predictors of ventricular tachycardia (VT) recurrence after ablation are lacking. Recently, a proarrhythmic effect of a chronic total occlusion (CTO) in a coronary artery has been suggested.

METHODS AND RESULTS

A total of 191 patients with prior MI were referred to our Hospital between 2010 and June 2013 for a first ablation of VT. Of these, 84 patients (44%) with stable coronary artery disease that underwent a coronary angiography during the index hospitalization were included in this study. A CTO in an infarct-related artery (IRA-CTO) was present in 47 patients (56%). Patients with and without IRA-CTO did not differ in terms of comorbidities, severity of heart failure, presentation of VT or acute outcome of ablation, that was completely successful in 93% of cases. At electroanatomic mapping, IRA-CTO was associated with greater scar and especially with greater area of border zone (34 cm(2) vs. 19 cm(2) , P = 0.001). Median follow-up was 19 months (IQR 18). At follow-up, patients with IRA-CTO had a significantly higher rate of VT recurrence (47% vs. 16%, P = 0.003). At multivariate analysis, IRA-CTO resulted to be an independent predictor of VT recurrence after ablation (HR 4.05, P = 0.004).

CONCLUSIONS

IRA-CTO is an independent predictor of VT recurrence after ablation and identifies a subgroup of patients with high recurrence rate despite a successful procedure. IRA-CTO is associated with greater scars and border zone area; however, this association does not completely justify its proarrhythmic effect.