Clinical Presentations and Timing of Intervention
The symptoms attributable to CTOs are no different than those of non-total occlusions. Patients may report characteristic angina or anginal equivalents, including dyspnoea and fatigue. CTO symptoms are by definition chronic and may sometimes be minimised through accommodation and denial.
Stable angina is present in many patients with CTO. Data from the FlowCardia’s approach to chronic total occlusion recanalisation (FACTOR) trial22 suggests that two thirds of the patients referred for the trial (which required symptoms and/or abnormal stress testing) had angina, that significantly impaired their quality of life (QoL). Dyspnoea is the most common anginal equivalent among patients with CTO. Safley et al.23 compared 98 patients with single-vessel CTO with 687 patients undergoing non-CTO PCI and reported similar alleviation in both dyspnoea and angina.
Numerous patients with CTO have been identified after presenting with other culprit lesions (46 % of patients with CTO presented with an acute coronary syndrome (ACS) in the Canadian Multicentre CTO Registry).2 Among patients presenting with ST-segment elevation acute myocardial infarction, approximately 10 % also have a CTO.2 The same study showed that 13 % of the CTO patients were asymptomatic or had minimal angina (Canadian classification angina class 0 and/or 1).2 The decision to revascularise the CTO in these patients depends on the indications discussed in section C. A careful search should be conducted for residual symptoms of myocardial ischaemia such as poor progression in cardiac rehabilitation, activity avoidance, residual dyspnoea, fatigue and angina, as well as residual ischaemic burden.
Timing of CTO-PCI
In most patients CTO-PCI should be performed electively and not ad hoc.24 Separating diagnostic angiography and CTO-PCI allows for a detailed discussion with the patient about the indications, goals, risks, and alternatives (such as medical therapy and coronary artery bypass graft surgery) to PCI.
Risks that are more specific to CTO PCI warrant discussion. These include the risk of radiation injury, perforation, tamponade and donor vessel injury. There is controversy on whether CTO PCI provides clinical benefit to asymptomatic patients, which should be discussed with the patient (section C, part 6).25 Finally, adequate pre-procedural planning, which is critical to maintaining high procedural success, is more challenging when performed on an ad hoc basis. On rare occasions, the clinical situation may force ad hoc CTO PCI. An example would be a patient who presents with an ACS due to a severely degenerated saphenous vein graft (SVG) with no option for embolic protection. Native vessel CTO-PCI might be preferable and required if the patient cannot be stabilised with medical therapy.26
The authors would like to thank Ms Sheila Agyeman for her invaluable effort in coordinating the manuscript creation process.