Ventricular Arrhythmias Among Implantable Cardioverter-Defibrillator Recipients for Primary Prevention

Evidence for Benefit of Percutaneous Coronary Intervention for Chronically Occluded Coronary Arteries (CTO) - Clinical and Health Economic Outcomes

Percutaneous revascularisation of a coronary chronic total occlusion (CTO) remains one of the technical frontiers of interventional cardiology. CTOs are common, and yet intervention is only attempted in 10 % of cases. CTO procedures are perceived to be technically challenging, lengthy, associated with significant risk and have only limited data to support the practise. Recent technical advances have dramatically increased the success rate, shortened procedural time and improved clinical outcomes. The aim of this article is to critically examine the data that supports CTO intervention, including specifically an appraisal of procedural safety, benefit and overall cost effectiveness.

Percutaneous Treatment of Coronary Chronic Total Occlusions Part 1: Rationale and Outcomes

Coronary chronic total occlusions (CTOs) are commonly encountered in patients with coronary artery disease. Compared to patients without coronary CTOs, those with CTO have worse clinical outcomes and lower likelihood of complete coronary revascularisation. Successful CTO percutaneous coronary intervention (PCI) can significantly improve angina and improve left ventricular function. Although currently unproven, successful CTO PCI might also reduce the risk for arrhythmic events in patients with ischaemic cardiomyopathy, provide better tolerance of future acute coronary syndrome, and possibly improve survival. Evaluation by a heart team comprised of both interventional and non-interventional cardiologists and cardiac surgeons is important for determining the optimal revascularisation strategy in patients with coronary artery disease and CTOs. Ad hoc CTO PCI is generally not recommended, so as to allow sufficient time for (a) discussion with the patient about the indications, goals, risks, and alternatives to PCI; (b) careful procedural planning; and (c) contrast and radiation exposure minimisation. Use of drug-eluting stents is recommended for CTO PCI, given the lower rates of angiographic restenosis compared to bare metal stents.

Contemporary overview and clinical perspectives of chronic total occlusions

Chronic total occlusions (CTOs) are often detected on diagnostic coronary angiograms, but percutaneous coronary intervention (PCI) for CTO is currently infrequently performed owing to high technical difficulty, perceived risk of complications, and a lack of randomized data. However, successful CTO-PCI can significantly increase a patient's quality of life, improve left ventricular function, reduce the need for subsequent CABG surgery, and possibly improve long-term survival. A number of factors must be taken into account for the selection of patients for CTO-PCI, including the extent of ischaemia surrounding the occlusion, the level of myocardial viability, coronary location of the CTO, and probability of procedural success. Moreover, in patients with ST-segment elevation myocardial infarction, a CTO in a noninfarct-related artery might lead to an increase in infarct area, increased end-diastolic left ventricular pressure, and decreased left ventricular function, which are all associated with poor clinical outcomes. In this Review, we provide an overview of the anatomy and histopathology of CTOs, perceived benefits of CTO-PCI, considerations for patient selection for this procedure, and a summary of emerging techniques for CTO-PCI.

Advances in the management of coronary chronic total occlusions

Chronic total occlusions (CTOs) have been called "the last frontier" of percutaneous coronary intervention (PCI) due to traditionally low success rates and high risk for restenosis and re-occlusion. Recent advances in equipment and crossing techniques have significantly increased CTO PCI success rates while maintaining low risk of complications. Specifically, the retrograde approach and controlled antegrade dissection and re-entry in conjunction with advanced guidewires and microcatheters have significantly improved procedural success rates. Moreover, the introduction of the "hybrid" approach has created a unified framework for operators to approach CTOs in a systematic and efficient fashion. Finally, drug-eluting stents, especially second generation, have improved long-term patency after CTO PCI.

[Ventricular tachycardia in postinfarction patients and coronary heart disease. Treatment and prognostic significance]

Patients with coronary heart disease are subject to an increased risk for sudden cardiac death (SCD). Within the first 30-90 days after the myocardial infarct the risk is particularly high. In times of implantable cardioverter-defibrillator (ICD) on the one hand and the ability to bridge high-risk periods with e. g. wearable defibrillator vests on the other, adequate risk stratification is essential. Currently, the main parameter for this is the left ventricular ejection fraction (LVEF). However, risk stratification by measurement of the LVEF has severe limitations, especially since the majority of patients suffering from SCD have a normal LVEF. Various other methods like ventricular ectopy, signal-averaged ECG, QRS width, microvolt T-wave alternans and programmed ventricular stimulation have been previously evaluated. None of these methods alone or in combination with a left ventricular function assessment was capable of improving the predictability of arrhythmic events significantly. Considering the multiple mechanisms that can lead to SCD, a single risk stratifier seems unrealistic. However, patients with chronic total occlusion of a coronary artery and residual or provocable ischemia have an increased risk for SCD. Therefore a combination of clinical and angiographic parameters seems reasonable. Advanced echocardiographic parameters e.g. mechanical dispersion could be used on a complementary role.

Validation of the J-chronic total occlusion score for chronic total occlusion percutaneous coronary intervention in an independent contemporary cohort

BACKGROUND

Chronic total occlusion (CTO) recanalization is a complex and technically challenging procedure. The J-CTO score has been proposed to stratify case complexity and procedural success rates. However, the score has never been tested outside the setting of the original study. Moreover, its predictive value when using a hybrid antegrade or retrograde approach is unknown. We investigated the performance of the J-CTO score for predicting procedure complexity and success in an independent contemporary cohort.

METHODS AND RESULTS

A total of 209 consecutive patients who underwent CTO recanalization by a high-volume operator were included. Clinical and angiographic data were prospectively collected. The J-CTO score was applied for each patient, and discrimination and calibration were evaluated in the whole cohort, and according to the approach (antegrade 47% and retrograde 53%). Clinical and angiographic differences were noted between the original and studied cohort. The mean J-CTO score was 2.18±1.26, and successful guidewire crossing within 30 minutes and final angiographic success were 44.5% and 90.4%, respectively. The J-CTO score demonstrated good discrimination (c statistic, >0.70) and calibration (Hosmer-Lemeshow P>0.1) in the whole cohort and for antegrade and retrograde approaches. However, the final success rate was not associated with the J-CTO score.

CONCLUSIONS

In this independent cohort, the J-CTO score showed good discriminatory and calibration capacity for guidewire CTO crossing within 30 minutes but it does not for final success rate. The J-CTO score helps to predict complexity of CTO recanalization, and the simplicity of the score supports the widespread use as a clinical tool.