ABC | Volume 110, Nº5, May 2018

Review Article Ybarra et al CTO PCI Review Arq Bras Cardiol. 2018; 110(5):476-483 and physical limitation, improved ventricular function, and decreased mortality when compared to patients whose recanalization was not successful. Sapontis et al. evaluated the quality of life of 1,000 patients submitted to OCT PCI. One month follow-up showed a significant improvement in all domains of the Seattle Angina Questionnaire (SAQ), Rose Dyspnea Scale and PHQ-8 scores. 47 In another study with 184 patients in a one-year follow-up, a significant improvement in the quality of life of patients submitted to successful CTO PCI was also observed. The improvement was similar in all patients, regardless of their clinical, anatomical or procedural complexity. 59 InMashayekhie et al., evaluated the impact of CTO recanalization on the physical capacity of 50 patients undergoing cardiopulmonary testing before and after 7 months. The successful intervention improved exercise capacity (maximal oxygen consumption and anaerobic threshold increased by 12 and 28%, respectively; p = 0.001 for both). 60 Several observational studies show a relationship of CTO recanalization in the reduction of clinical events. Jang et al. compared CTO revascularization (by PCI or by surgery) with drug therapy in 738 patients with well-developed collaterals. The combined prognostic analysis at 42 months showed a 73% reduction in the incidence of cardiac death. 61 The Italian CTO Registry assessed the clinical outcomes of 1,777 patients, showing lower cardiac mortality (1.4, 4.7 and 6.3%, p < 0.001) and MACE at one year (2.6, 8.2 and 6.9%, p < 0.001) in patients treated with PCI when compared to clinical treatment or surgery. In this study, the group receiving optimized medical treatment presented higher rates of MACE, death and re-hospitalization. 62 To date, three randomized controlled trials have evaluated the potential benefits of CTO PCI. The EXPLORE study included 304 patients with acute myocardial infarction (AMI) who underwent primary PCI and presented CTO in a non‑infarct-related artery. They were randomized to CTO PCI in a second moment versus optimized medical treatment (OMT). At the 4-month follow-up, similar left ventricular function was observed in both groups, although a significant improvement in the ejection fraction was observed in the subgroup of patients with anterior wall AMI. The inclusion of patients without viability research may have limited a possible PCI positive result. 63 The DECISION-CTO study randomized 834 patients with CTO for OMT vs . OMT + CTO PCI. 64 In the 3-year clinical follow-up, CTO PCI as the initial treatment strategy did not provide a decrease in MACE, the primary outcome of the study. However, this study had important limitations: it was terminated early before reaching the pre-specified number of patients required, with low inclusion rate of patients per center; patients with low severity and low symptomatic status were included; and there was high cross-over rate for the intervention group (20%). The Euro CTO Trial randomized 407 patients with stable coronary disease for OMT vs . OMT + CTO PCI. The primary outcome was an improvement in the quality of life, as assessed by SAQ. 55 Although there were also limitations related to selection bias (termination of the study with only one third of the planned sample due to slow inclusion), randomized patients to PCI CTO showed a significant improvement in angina frequency, physical limitation, and quality of life in the 12-month follow-up. In a recent meta-analysis including 9 studies with more than 6,400 patients, the long-term clinical outcomes of successful CTO recanalization were compared to those in whom the recanalization was unsuccessful. In this study, the risk of death, AMI and MACE was approximately 50% lower in patients with CTO recanalization, with a 90% lower incidence of myocardial revascularization. 65 Brazilian reality The percutaneous treatment of CTO in Brazil with the contemporary techniques described here can still be considered incipient due to the limited availability of dedicated materials in our country, affecting the adequate training of the operators. Recently, following the worldwide trend of treatment of these lesions based not only on the anatomy, but also on the symptoms and the clinical indication, several institutions and interventionists started to dedicate themselves to this area. The Brazilian Society of Hemodynamics and Interventional Cardiology (SBHCI) has stimulated this development, having already organized two dedicated courses (CTO Summit Brazil 2016 and 2017) and supporting specific regional events. The role of specific training to perform this type of procedure is imperative, both for the knowledge of the techniques and the equipment used. Most operators develop their skills by participating in courses and procedures with proctors. There are also dedicated training programs, however limited to few centers in the world. 48, 66 Conclusion The CTO PCI is a rapidly advancing field. With the use of the right equipment and current techniques, high volume and expertise centers achieve high success rates. Although current evidence is favorable to PCI, prospective randomized controlled good quality trials are still needed to define the best indications and the most appropriate techniques for intervention in this challenging population. Author contributions Conception and design of the research, Analysis and interpretation of the data and Writing of the manuscript: Ybarra LF, Quadros AS; Acquisition of data: Ybarra LF; Obtaining financing and Critical revision of the manuscript for intellectual content: Ybarra LF, Cantarelli MJC, Lemke VMG, Quadros AS. Potential Conflict of Interest Dr. Luiz Fernando Ybarra consultant and speaker: Boston Scientific (Canadá/Portugal) Dr. Alexandre S. Quadros educational support: Medtronic, Boston, Abbott Vascular, Terumo, Acrosstak; Research Funds: Sanofi, Amgen, Daiichi-Sanchio, Medtronic; 480