Evaluation of fractional flow reserve and atherosclerotic plaque characteristics on coronary non-contrast T1-weighted magnetic resonance imaging

Abstract

AbstractBackgroundThe relationship between high-risk coronary plaque characteristics regardless of the severity of lesion stenosis and myocardial ischemia remains unsettled. High-intensity plaques (HIPs) on non-contrast T1-weighted magnetic resonance imaging (T1WI) have been characterized as high-risk coronary plaques. We sought to elucidate whether the presence of coronary HIPs on T1WI influences fractional flow reserve (FFR) in the distal segment of the vessel.MethodsWe retrospectively analyzed 232 vessels in 190 patients with chronic stable coronary syndrome who underwent both invasive FFR measurement and coronary T1WI using a multicenter registry. The plaque-to-myocardial signal intensity ratio (PMR) of the most stenotic lesion was evaluated; a coronary plaque with PMR >1.4 was defined as a HIP.ResultsThe median PMR of coronary plaques on T1WI in vessels with FFR ≤0.80 was significantly higher than that of plaques with FFR >0.80 (1.18 [interquartile range (IQR): 0.96–1.45] vs. 0.97 [IQR: 0.85–1.12]; p<0.001)). Multivariable analysis showed that an increase in PMR of the most stenotic segment is associated with lower FFR (beta-coefficient, –0.051; p<0.001). The presence of coronary HIPs was an independent predictor of FFR ≤0.80 (odds ratio, 5.54; 95% confidence interval, 1.50–20.5; p=0.010).ConclusionsCoronary plaques with high PMR are associated with low FFR in the corresponding vessel, indicating that plaque morphology might influence the degree of myocardial ischemia.Trial registrationUMIN 000029246Clinical PerspectiveWhat is new?Incremental of coronary plaque to myocardial signal intensity ratio on T1-weithted magnetic resonance imaging (T1WI), which is represented as instability of coronary plaques was associated with low factional flow reserve (FFR) value in patients with chronic coronary syndrome (CCS).The presence of a coronary high-intensity plaque (HIP) detected with T1WI is a strong predictor of low fractional flow reserve (FFR) even after adjusting age, gender, proximal left anterior descending artery, the severity of stenosis in the most stenotic lesion and variables related to plaque volume evaluated on computed tomography angiography.What are the clinical implications?Non-contrast T1WI without contrast media is an anatomy-based, but not ischemia-based, screening method for predicting future coronary events.The presence of a coronary HIP on T1WI, which represents a complicated atheroma, is an additional determinant of coronary physiology.