Association of Coronary Stenosis and Plaque Morphology With Fractional Flow Reserve and Outcomes

Abstract

Having a normal FFR requires unimpaired vasoregulatory ability and significant luminal stenosis. Therefore, FFR should identify lesions that are unlikely to possess large necrotic core, rendering them safe for treatment with medical therapy alone. Further studies are warranted to determine whether revascularization decisions in patients with stable coronary artery disease could be improved by assessment of both plaque composition and ischemia.

Clues to Discordance and Dissimilarity Between Coronary Stenosis and Lesion-Specific Ischemia

“…Alternatively, the authors propose that coronary microvascular dysfunction (in the absence of obstructive coronary artery disease) may be operational and would be more prevalent among hypertensive, dyslipidemia, and diabetic patients. 5 Thus, discordance would occur with physiological abnormalities or ischemia without a high-grade stenosis along with stenosis without ischemia, as previously described by Ahmadi et al 3 Data from positron emission tomography imaging support the independent prognostic significance of reduced coronary flow reserve even among patients with nonobstructive coronary artery disease. 6 Although there are differences between positron emission tomography and invasive physiological measures, these data underscore the complexity of clinical care and the limitations of management based on anatomic data alone.…”

Significance of Microvascular Function in Visual—Functional Mismatch Between Invasive Coronary Angiography and Fractional Flow Reserve

“…However, given the substantial population of patients showing FFR within the gray zone ranging from 0.75 to 0.80 in the reverse mismatch group, superiority of PCI for those lesions may deserve further consideration 34. Previous studies have suggested the impact of plaque characteristics on FFR values for a given anatomical stenosis in an epicardial coronary artery 35. The present study reports the association of CFR and IMR with FFR.…”

Prognostic Determinants of Coronary Atherosclerosis in Stable Ischemic Heart Disease

“…101 This may explain why FFR-negative lesions are safe to defer to medical therapy despite a significant degree of luminal narrowing; a 0.2% 2-year rate of MI arising from FFR-negative lesions was observed in the FAME study despite 104 lesions having 70% to 90% luminal narrowing. 10,101 A related intriguing question that needs to be addressed is whether all FFR-positive plaques have the same prognosis, and thus do all require revascularization? Based on the FAME 2 data, only 8.2% of FFR-positive plaques that were randomized to medical therapy resulted in death or MI within 2 years.…”

“…47 Although some severely stenotic lesions may not result in detectable ischemia (stenosis without ischemia), others with only a mild-moderate degree of angiographic stenosis may result in ischemia (ischemia without stenosis). 100,101 Features other than the degree of luminal stenosis, such as lesion length, entrance angle, exit angle, size of the reference vessel, and absolute flow relative to the territory supplied, are important in determining FFR-verified lesion-specific ischemia 50 and might explain the discordance between anatomy and physiology in some cases. Recently, it has been shown that the presence of high-risk plaque features, especially large low attenuation plaque, a CTA surrogate for necrotic core, is strong predictor of FFR-verified ischemia independent of degree of luminal stenosis.…”

“…Based on the FAME 2 data, only 8.2% of FFR-positive plaques that were randomized to medical therapy resulted in death or MI within 2 years. 12,101 We propose that identification of FFR-positive lesions that have a large plaque burden and necrotic core may further risk stratify SIHD patients with the highest likelihood of future MACE, those who would benefit most by revascularization ( Figure 5). As the ischemic potential and morphological characteristics of lesions have not been simultaneously studied in any natural history study to date, this hypothesis requires future validation in appropriately conducted prospective studies.…”