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A chronic total occlusion (CTO) is defined as complete occlusion of the coronary vessel with TIMI 0 flow, present for an (estimated) duration of ≥3 months. In patients with significant coronary artery disease (defined as at least one major epicardial vessel with a stenosis ≥70%), a CTO is common and found in approximately half of such patients.1 Importantly, the presence of a CTO has a major impact on management, and is a strong predictor against recommending percutaneous coronary intervention (PCI), with a preference for medical treatment or coronary artery bypass surgery (CABG).1 This relates to perceived difficulties in recanalisation; however, in recent years, through advances in specialist equipment and techniques, expert operators have significantly improved recanalisation rates leading to a resurgence of interest in CTO PCI. The purpose of this article is to review the available clinical data and discuss the contemporary management of CTOs by PCI.
Why is it beneficial to open a CTO?
Multiple studies have demonstrated that successful CTO PCI improves quality of life, through reducing symptoms of angina, improving exercise capacity, improving left ventricular function, and reducing the need for subsequent CABG.2 3 w1 Furthermore, multiple registries have demonstrated that successful CTO PCI is associated with improved long term survival compared to patients with an unsuccessful PCI (table 1),3 4 w1–3 with some data suggesting that this is particularly the case for left anterior descending artery occlusions.w4–6 The benefit in outcome is only partly explained by adverse events directly associated with an unsuccessful procedure, and appears to relate to fewer events occurring at long term follow-up. The potential reasons for this are poorly defined but possibly include a reduction in ischaemia driven arrhythmia. Certainly patients undergoing primary PCI for ST elevation myocardial infarction (STEMI) …