Percutaneous intervention for chronic total occlusion: integrating strategies to address an unmet need

Chronic total occlusion (CTO) remains a challenging lesion subset when considering percutaneous coronary intervention (PCI). Until recently, CTO lesions were associated with relatively low procedural success rates ranging between 60–70% despite evidence of considerable case selection1 ,2 However, the emergence of new techniques and technologies is revolutionising the field, such that procedural success rates in excess of 90% have been described by specialist operators.3 While it has long been appreciated that CTO revascularisation can improve symptoms,4 there is an increasing body of evidence to suggest prognostic benefit may follow.5 In this issue of Heart , Michael et al describe outcomes following CTO PCI among patients with previous coronary artery bypass graft surgery (CABG).6 They demonstrate that prior CABG remains a challenge in CTO PCI, with lower procedural success rates than CTO lesions in previously ungrafted patients. However, the most powerful aspect of their data is that the reporting US centres are consistently achieving high rates of procedural success (85%) despite treating increasingly complex patients. In their cohort 37% of patients had undergone prior CABG, a substantially greater proportion than any other reported registry. This suggests greater patient selection among previous registries, where CTO patients with more complex disease may have been excluded from revascularisation, a situation likely to reflect real world clinical practice. Patients who have symptoms, significant ischaemia, and/or myocardial viability may often be excluded from revascularisation on the basis of feasibility of percutaneous revascularisation —that is, anatomy rather than clinical need. Although chronic occlusions may be present in up to 35% of patients undergoing coronary angiography,7 CTO PCI accounts for only around 5% of all elective PCI procedures.8 Many patients with single vessel de novo CTO are not offered revascularisation at all. Among patients with multivessel disease undergoing PCI, the …