Non-invasive multiparametric evaluation of patients with chronic total occlusions compared with single-photon emission computed tomography results

BACKGROUND: Chronic total occlusion (CTO) is a common finding on coronary angiograms of patients diagnosed with coronary artery disease, with an incidence ranging from 15 to 25%. Despite its high incidence, this type of coronary lesion is rarely treated with percutaneous coronary intervention. The key to success appears to be appropriate qualification for revascularization. Asymptomatic patients should be assessed for inducible ischemia within the occluded vessel territory to detect patients with a high ischemic burden, defined as inducible ischemia involving > 10% of the myocardium. Single-photon emission computed tomography (SPECT) is a well-established method of myocardial perfusion assessment; however, it is not widely available, especially in less developed regions. The aim of the study was to evaluate CTO patients to identify clinical parameters that could predict the presence of relevant inducible ischemia measured by SPECT. METHODS: The study included 50 patients with a single-vessel CTO and without any other significant coronary artery stenosis. Patients underwent clinical examination, laboratory tests, echocardiography, 6-minute walk test, cardiopulmonary exercise testing, exercise impedance cardiography, and SPECT. RESULTS: The only parameters associated with a high ischemic burden were CTO location (in the left anterior descending artery and circumflex artery) and one echocardiographic parameter: myocardial lateral wall longitudinal strain. CONCLUSIONS: Given the high incidence of CTO, there is an increasing need to define non-invasive markers that could predict the presence of a high ischemic burden and good clinical outcome after revascularization. Echocardiographic longitudinal strains are worth further research in terms of their utility in predicting inducible ischemia.