Functional Angioplasty: Definitions, Historical Overview, and Future Perspectives

Figures

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  Figure 1. Physiologic indices to define the presence of myocardial ischemia. Various diagnostic methods are used for the physiological assessment of CAD. The area in circles represents physiologically significant CAD, and the complement of the circled area physiologically non-significant CAD. Electrocardiographic and regional wall motion abnormalities during stress are a direct evidence of inducible myocardial ischemia, whereas changes in coronary flow or coronary perfusion pressure during stress are surrogates for inducible myocardial ischemia. CAD = coronary artery disease; CFR = coronary flow reserve; CMR = cardiovascular magnetic resonance imaging; CTP = computed tomography perfusion; ECG = electrocardiography; Echo = echocardiography; FFR = fractional flow reserve; FFRCT = fractional flow reserve derived from coronary computed tomography angiography; iFR = instantaneous wave-free ratio; Pa = aortic pressure; Pd = distal coronary artery pressure; PET = positron emission tomography; SPECT = single-photon emission computed tomography; QFR = quantitative flow ratio.

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  Figure 2. Timeline of the reference standards for the assessment of myocardial ischemia. The gold standard for the diagnosis of myocardial ischemia has been changed over the past several decades. Although FFR is a surrogate for inducible myocardial ischemia, it is nowadays used as a reference standard to evaluate the diagnostic performance of new ischemic indices. CMR = cardiovascular magnetic resonance imaging; CTP = computed tomography perfusion; ECG = electrocardiography; Echo = echocardiography; FFR = fractional flow reserve; FFRCT = fractional flow reserve derived from coronary computed tomography angiography; PET = positron emission tomography; SPECT = single-photon emission computed tomography; QFR = quantitative flow ratio.

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  Figure 3. Key determinants of clinical manifestations in CAD. CAD is manifested with either acute coronary syndrome or chronic coronary syndrome. Acute coronary events leading to death or MI are primarily determined by atherosclerotic plaque burden, whereas angina symptoms are determined by the degree of luminal stenosis (ischemia-causing stenosis). CAD = coronary artery disease; MI = myocardial infarction.

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  Figure 4. Therapeutic approaches for CAD based on symptoms and ischemia. If patients have significant left main CAD, significant CAD with severe LV dysfunction, or severe multivessel CAD with diabetes, CABG is first recommended. In other cases, medical treatment should be considered the first-line therapeutic option with revascularization therapy (PCI or CABG) reserved for those with medically refractory angina and objective evidence of ischemia. Treatment in parentheses may be considered as an alternative approach in certain types of patients. CABG = coronary artery bypass graft surgery; CAD = coronary artery disease; CTA = coronary computed tomography angiography; LV = left ventricular; PCI = percutaneous coronary intervention.