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OBJECTIVES This study is to determine the management and clinical outcomes of patients investigated with coronary computed tomography angiography (CCTA)-derived fractional flow reserve (FFRCT) according to sex.BACKGROUND Women are underdiagnosed with conventional ischemia testing, have lower rates of obstructive coronary artery disease (CAD) at invasive coronary angiography (ICA), yet higher mortality compared to men. Whether FFRCT improves sex-based patient management decisions compared to CCTA alone is unknown.METHODS Subjects with symptoms and CAD on CCTA were enrolled (2015 to 2017). Demographics, symptom status, CCTA anatomy, coronary volume to myocardial mass ratio (V/M), lowest FFRCT values, and management plans were captured. Endpoints included reclassification rate between CCTA and FFRCT management plans, incidence of ICA demonstrating obstructive CAD ($50% stenosis) and revascularization rates.RESULTS A total of 4,737 patients (n = 1,603 females, 33.8%) underwent CCTA and FFRCT. Women were older (age 68 +/- 10 years vs. 65 +/- 10 years; p < 0.0001) with more atypical symptoms (41.5% vs. 33.9%; p < 0.0001). Women had less obstructive CAD (65.4% vs. 74.7%; p < 0.0001) at CCTA, higher FFRCT (0.76 +/- 0.10 vs. 0.73 +/- 0.10; p < 0.0001), and lower likelihood of positive FFRCT

OBJECTIVES This study sought to investigate the impact of low tube voltage scanning heterogeneity of coronary luminal attenuation on plaque quantification and characterization with coronary computed tomography angiography (CCTA). BACKGROUND The impact of low tube voltage and coronary luminal attenuation on quantitative coronary plaque remains uncertain. METHODS A total of 1,236 consecutive patients (age: 60 +/- 9 years; 41% female) who underwent serial CCTA at an interval of $2 years were included from an international registry. Patients with prior revascularization or nonanalyzable coronary CTAs were excluded. Total coronary plaque volume was assessed and subclassified based on specific Hounsfield unit (HU) threshold: necrotic core, fibrofatty plaque, and fibrous plaque and dense calcium. Luminal attenuation was measured in the aorta. RESULTS With increasing luminal HU (500 HU), percent calcified plaque was increased (16%, 27%, and 40% in the median; P < 0.001), and fibrofatty plaque (26%, 13%, and 4%; P < 0.001) and necrotic core (1.6%, 0.3%, and 0.0%; P < 0.001) were decreased. Higher tube voltage scanning (80,100, and 120 kV) resulted in decreasing luminal attenuation (689 +/- 135, 497 +/- 89, and 391 +/- 73 HU; P < 0.001) and calcified plaque volume (59%, 34%, and 23%; P < 0.001) and increased fibrofatty plaque (3%, 9%, and 18%; P < 0.001) and necrotic core (0.2%, 0.1%, and 0.6%; P < 0.001). Mediation analysis showed that the impact of 100 kV on plaque composition, compared with 120 kV, was primarily caused by an indirect effect through blood pool attenuation. Tube voltage scanning of 80 kV maintained a direct effect on fibrofatty plaque and necrotic core in addition to an indirect effect through the luminal attenuation. CONCLUSIONS Low tube voltage usage affected plaque morphology, mainly through an increase in luminal HU with a resultant increase in calcified plaque and a reduction in fibrofatty and necrotic core. These findings should be considered as CCTA-based plaque measures are being used to guide medical management and, in particular, when being used as a measure of treatment response. (Progression of Atherosclerotic Plaque Determined by Computed Tomographic Angi-ography Imaging [PARADIGM]; NCT02803411) (J Am Coll Cardiol Img 2021;14:2429-2440) (c) 2021 by the American College of Cardiology Foundation.