Chronic total occlusion interventions

Indications

CTO PCI should be performed when the anticipated benefit is greater than the potential risk ( Fig. 8.1 ). The main benefit of CTO PCI is symptom improvement (i.e., angina and dyspnea in most patients). The more symptomatic the patient, the higher the potential benefit of CTO PCI. CTO PCI can improve exercise capacity, increase anaerobic threshold, and alleviate depression. It continues to be debated whether CTO PCI can improve left ventricular systolic function and reduce the risk of arrhythmias or death.

The risks of CTO PCI can be acute during the perioperative period (such as acute myocardial infarction, perforation, need for emergency coronary artery bypass graft [CABG] surgery, or death) or chronic (such as restenosis and stent thrombosis).

The optimal coronary revascularization modality in patients with coronary CTOs depends on coronary anatomy and comorbidities, with “best practice” currently involving individualizing patient treatment decisions with discussion between cardiac surgery, cardiology, and interventional cardiology in a Heart Team approach. Some patients with coronary CTOs may be better served with CABG surgery, especially if they have multivessel complex coronary artery disease and they are diabetic. Other patients may be better served by CTO PCI, especially if they have had prior CABG, if they are poor surgical candidates, or if they have single vessel coronary artery disease ( Fig. 8.2 ).

In the 2021 American College of Cardiology (ACC)/American Heart Association (AHA) PCI guidelines, CTO PCI carries a class IIB/level of evidence B recommendation: “In patients with suitable anatomy who have refractory angina on medical therapy, after treatment of non-CTO lesions, the benefit of PCI of a CTO to improve symptoms is uncertain.” In the 2018 European Society of Cardiology (ESC)/European Association of Cardiothoracic Surgery (EACS) guidelines on myocardial revascularization, CTO PCI carries a class IIA/level of evidence B recommendation: “Percutaneous recanalization of CTOs should be considered in patients with angina resistant to medical therapy or with large area of documented ischemia in the territory of the occluded vessel.

In summary, at present the main goal of CTO PCI is to improve patient symptoms that are caused by myocardial ischemia (angina, exertional dyspnea, and sometimes fatigue) despite optimal medical therapy. A detailed conversation with patients who are candidates for CTO PCI is critical to ensure full understanding of the potential risks and benefits of the procedure.

Planning for CTO PCI: Dual angiography performance and interpretation

Dual angiography is critical for the success and safety of CTO PCI. It should be done in nearly all cases, except when the collateral circulation is originating exclusively from the CTO vessel. The donor vessel is injected first, followed by injection of the CTO vessel 2 to 3 seconds later using low magnification and avoiding panning that can result in degradation of the image quality. Coronary computed tomography angiography (CCTA) is another imaging technique that can help assess the anatomy of the CTO vessel.

Angiographic review of the CTO anatomy focuses on the following four characteristics ( Fig. 8.3 ): (1) proximal cap morphology; (2) occlusion length, course, and composition (e.g., calcium); (3) quality of the distal vessel; and (4) collateral circulation. Moreover, non-CTO lesions are reviewed because the presence of additional lesions can help determine the optimal coronary revascularization strategy (PCI vs. CABG), and if PCI is selected, decisions must be made about the sequence in which CTO and non-CTO lesions will be revascularized.