The Hybrid Approach to Intervention of Chronic Total Occlusions

The “hybrid” approach to chronic total occlusion (CTO) percutaneous coronary intervention (PCI) was developed to provide guidance on optimal crossing strategy selection. Dual angiography remains the cornerstone of clinical decision making in CTO PCI. Four angiographic parameters are assessed: (a) morphology of the proximal cap (clear-cut or ambiguous); (b) oc-clusion length; (c) distal vessel size and presence of bifurcations beyond the distal cap; and (d) location and suitability of a retrograde con-duit (collateral channels or bypass grafts) for retrograde access. Antegrade wire escalation is favored for short (<20 mm) occlusions, usually escalating rapidly from a soft tapered-tip polymer-jacketed guidewire to a stiff polymer-jacketed or tapered-tip guidewire. Antegrade dissection/re-entry is favored in long (≥20 mm long) occlusions, try-ing to minimize the dissection length by re-entering into the distal true lumen immediately after the occlusion. Primary retro-grade approach is preferred for lesions with an ambiguous proximal cap, poor distal target, good interventional collaterals, and heavy calcification, as well as chronic kidney disease. The “hybrid” approach advocates early change between strategies to enable CTO crossing in the most efficacious, efficient, and safe way. Several early studies are demonstrating high success and low complication rates with use of the “hybrid” approach, supporting its expanding use in CTO PCI. .     

Training Standards and Recommendations for Intervention on Chronic Total Occlusions

Despite major advances in coronary intervention, the recanalization of a chronic total occlusion (CTO) remains a challenge for many interventional cardiologists. Complex anatomy and lesion characteristics demand a special set of skills for procedural success. Provided patient selection is appropriate, CTO intervention can confer a variety of benefits including relief of angina, improvement in left ventricular function and reduction in ischemic burden. The chances of procedural success are enhanced by having a dedicated CTO program. This involves adequate training of staff, quality control and availability of equipment. A diverse toolkit allows variation in strategy and increases procedural success. Further, skills and equipment are required to manage complications like vessel dissection, perforation and the resultant ischemic or mechanical complications. These procedures can often be lengthy and giving careful consideration to peri-procedural issues like radiation exposure and contrast dose plays a vital role in ensuring optimal patient outcomes and radiation hygiene. In this article we review the evidence behind indications for CTO intervention and discuss the development of a CTO program.     

Antegrade Techniques for Chronic Total Occlusions

By convention, a total obstruction of the coronary artery with no flow at the occluded segment that has been present for at least 3 months is termed as chronic total occlusion or CTO. This is to be distinguished from a sudden occlusion of the coro-nary artery lumen by a thrombus during an acute myocardial infarction. Percutaneous coronary intervention (PCI) of CTO is increasingly being performed by interventional cardiologists with improved success rates. In this article, the focus will be on antegrade techniques that will assist the operator to maximise the success rates and to minimise the complications.     

The Role of Coronary Collaterals in Chronic Total Occlusions

A chronic total occlusion (CTO) describes a completely occluded coronary artery. This type of lesion is found in about 18% of all significant lesions in patients with coronary artery disease. A system of collateral connections are observed in almost all of these lesions, which have the capacity to prevent myocardial necrosis and may even uphold metabolic supply to the territory distal to an occlusion to maintain full contractile capacity. During exercise these collaterals are limited in their functional reserve, and more than 90% of patients with a well collateralized occlusion will experience ischemia. in the absence of ideal animal models that mimic the human collateral circulation, we need to rely on studies in man. The knowledge of collateral physiology in man has increased considerably over the past two decades with the advent of intracoronary sensors of coronary pressure and flow velocity. A number of basic physiologic questions have been answered by these studies. The blood supply through coronary arteries depends on a complex array of in general serial resistance systems, with an additional array of multiple parallel resistances on the collateral level.There seems to be a great interindividual variability in the ability to recruit preformed collateral connections in the case of an epicardial occlusion. Collateral function can develop to a similar functional level in patients post myocardial infarction with large akinetic territories as it does in patients with normal preserved regional function. The presence of viability is thus not a prerequisite for collateral development. The question of practical relevance in the era of interventional therapy of chronic occlusions is also, whether a patient with coronary artery disease will remain protected by collaterals after removing the obstruction in the collateralized artery, or whether collaterals regress and lose their functional capacity. Both developments are observed again mainly depending of individual predisposition.     

Advances in Retrograde Technique for Coronary Chronic Total Occlusions

Despite a short lag period since its development the retrograde approach has been increasingly integrated within the treatment strategies for the percutaneous treatment of coronary chronic total occlusions. This review article discuss which anatomical features argue most powerfully for its use, the specific skills required for its uptake and the technology which has facilitated these developments.     

Chronic Total Artery Occlusions in Noninfarct-Related Coronary Arteries

It has been rarely encountered some patients in clinical practice with coronary artery chronic total occlusion (CTO) on angiography but no any clinical history or electrocardiographic, echocardiographic, or left ventriculographic evidence of previous myocardial infarction. These noninfarct-related artery CTO (non-IRA CTO) lesions may be used as a clinical role model of endogenous cardioprotective mechanisms in addition to continuing the process of atherosclerosis. The objective of this study was to characterize the clinical characteristics of patients with non-IRA CTO patients and compared them to those with infarct-related CTO (IRA-CTO). We reviewed our invasive cardiology database searching for the CTO of any major coronary arteries, and assessed whether or not they have the clinical history or electrocardiographic, echocardiographic, and left ventriculographic evidence of previous myocardial infarction. Interestingly, we detected that all these patients with non-IRA CTO had diabetes mellitus, and the clinical and demographic features of these non-IRA CTO patients were compared with age- and sex-matched diabetic IRA-CTO patients with regard to conventional coronary risk factors and the angiographic collateral grading system. There were total 99 CTO patients (49 patients with non-IRA CTO and 50 patients with IRA-CTO).All patients with non-IRA CTO had better collateral circulation (96 vs. 40% p < 0.001) compared with those having IRA-CTO. The only significant difference between the groups was the status of current smoking (4 vs. 88%; p < 0.001). The present study showed that the non-IRA CTOs were associated with diabetes mellitus and better collateral development compared with IRA-CTO. In diabetic patients, the concomitant smoking use may be harmful by preventing endogenous cardioprotective mechanisms.     

Applied Pathology for Interventions of Coronary Chronic Total Occlusion

Percutaneous coronary intervention of chronically occluded vessels can result in significant improvement in symptoms, relieve myocardial ischemia, and affect a reduction in major adverse cardiac events. Likelihood of achieving successful revascularization can be significantly enhanced with a thorough understanding of the pathology of these occluded coronary arteries. In this chapter, various steps and techniques to cross the CTO lesion and recanalize it are discussed in details.     

Retrograde Coronary Chronic Total Occlusion Intervention

Coronary chronic total occlusion (CTO) is a frequent finding in patients with coronary artery disease. It remains one of the most challenging subsets, accounting for 10-20% of all percutaneous coronary interventions (PCI). Although remarkable progress in PCI has been made, it is reasonable to state that successful recanalization of CTO represents the “last frontier” of PCI. PCI of CTOs has been limited historically by technical success rates of 50-70%. The introduction of enhanced guidewires, microcatheter, channel dilatator with increasing operator experience, and innovative techniques such as the retrograde approach have raised hopes for better outcomes. This article goes into depth into various strategies of retrograde approach in CTO.     

Radiation Safety During Interventions of Coronary Chronic Total Occlusion

During percutaneous coronary interventions (PCI) for chronic total occlusion (CTO), prolonged procedures increase the risk of excessive radiation exposure. These situations harbor a major concern to protect patients and personnel in the cardiac interventional laboratory (CCL). Important questions regarding radiation safety for interventional cardiologists performing PCI for CTO lesions are discussed and concrete applications are suggested.     

Update in the Percutaneous Management of Coronary Chronic Total Occlusions

Percutaneous coronary intervention (PCI) for chronic total occlusions (CTOs) has been rapidly evolving during recent years. With improvement in equipment and techniques, high success rates can be achieved at experienced centers, although overall success rates remain low. Prospective, randomized-controlled data regarding optimal use and indications for CTO PCI remain limited. CTO PCI should be performed when the anticipated benefit exceeds the potential risk. New high-quality studies of the clinical outcomes and techniques of CTO PCI are needed, as is the expansion of expert centers and operators that can achieve excellent clinical outcomes in this challenging patient and lesion subgroup. In the current review the authors summarize the latest publications in CTO PCI and provide an overview of the current state of the field.     

药物洗脱支架治疗完全闭塞病变的疗效观察

目的:评估在冠心病患者,不同药物洗脱支架对于治疗冠状动脉完全闭塞病变的远期疗效。方法:122例完全闭塞病变[冠状动脉溶栓治疗临床试验(TIMI)0级血流,且闭塞时间>3个月]并成功置入Firebird支架(Firebird组,n=58)、Cypher支架(Cypher组,n=40)和Taxus支架(Taxus组,n=24)的患者入选本研究。术后12个月随访时进行定量冠状动脉造影分析,并观察住院期间,30天和12个月时不良心脏事件的发生和靶病变重复血管重建。结果:3组的基本临床特征和基础冠状动脉造影结果相似,支架置入成功率均为100。术后支架内最小管腔直径,3组间差异无统计学意义(P>0.05)。住院期间3组均无靶病变重复血管重建和死亡发生。在30天时,3组均无支架内血栓形成。12个月随访期间,严重不良心脏事件发生率和靶病变重复血管重建率,在Firebird组为5.2和3.4;Cy-pher组为10.0和5.0,其中死亡1例(2.5);Taxus组为12.5和12.5,均无显著性差异(P>0.05)。12个月定量冠状动脉造影分析显示:支架内最小管腔直径和管腔狭窄直经,在Firebird组和Cypher组无显著差...     

Intravascular Ultrasound Guided Percutaneous Coronary Intervention for Chronic Total Occlusion

Chronic total occlusion (CTO), a fascinating and dynamic niche in the realm of coronary artery disease, represents a major technical challenge for interventional cardiologists despite evolution of better guidewires, devices, experience and techniques. Effective wiring technique is the corner stone to success of percutaneous coronary intervention (PCI) in CTO. As a guide for guidewire crossing in CTO, coronary angiography is limited. On the other hand, intravascular ultrasound (IVUS) enhances the ability to identify coronary anatomy, the exact location of the guidewires within an artery, discriminating a true lumen from the false lumen before guidewire crossing. Some angiographic features have been suggested to be predictive of procedural failure, including blunt stump with a side branch at the site of occlusion. Novel use of IVUS can recognize the optimal entry point and evaluate if a guidewire properly penetrates the proximal cap of CTO.     

冠状动脉慢性完全闭塞性病变介入治疗与造影剂肾病风险的相关性研究

目的探讨冠状动脉慢性完全闭塞性病变(chronic total occlusion,CTO)介入治疗与造影剂肾病发生风险的相关性。方法纳入2013年阜外医院所有接受介入治疗的患者,分为CTO组和非CTO组,分析其造影剂肾病的发生情况及危险因素。结果共入选9924例患者,CTO组(876例)和非CTO组(9048例)患者的造影剂肾病发生率分别为2.2%和1.8%(P=0.454)。经倾向性评分匹配后CTO组(850例)和非CTO组(850例)的造影剂肾病发生率分别为2.2%和1.4%(P=0.204)。经多因素分析,倾向性评分前后,CTO均不是造影剂肾病的独立危险因素(P>0.05)。结论CTO患者和非CTO患者接受介入治疗造影剂肾病发生风险相当。     

冠状动脉慢性完全闭塞合并分叉病变介入治疗

慢性完全闭塞病变成为经皮冠脉介入术治疗"最后的堡垒"。成功开通闭塞病变,可改善心绞痛症状、生活质量、左室射血分数和远期预后。慢性闭塞合并分叉病变时,介入治疗操作更复杂。随着各种正向/逆向技术发展和新型器械的应用,闭塞血管开通率逐渐提升,但分支闭塞风险仍较高。分支闭塞导致围手术期心肌梗死和主要心脏不良事件发生率升高。慢性闭塞合并分叉病变介入治疗过程中容易出现冠状动脉夹层和假腔,影响分支血流。使介入手术难度增加、成功率降低和并发症增多。