Diagnostic accuracy and discrimination of ischemia by fractional flow reserve CT using a clinical use rule: results from the Determination of Fractional Flow Reserve by Anatomic Computed Tomographic Angiography study.

Fractional flow reserve (FFR) is the gold standard for determining lesion-specific ischemia. Computed FFRCT derived from coronary CT angiography (coronary CTA) correlates well with invasive FFR and accurately differentiates between ischemia-producing and nonischemic lesions. The diagnostic performance of FFRCT when applied in a clinically relevant way to all vessels ≥ 2 mm in diameter stratified by sex and age has not been previously examined. Two hundred fifty-two patients and 407 vessels underwent coronary CTA, FFRCT, invasive coronary angiography, and invasive FFR. FFRCT and FFR ≤ 0.80 were considered ischemic, whereas CT stenosis ≥ 50% was considered obstructive. The diagnostic performance of FFRCT was assessed following a prespecified clinical use rule which included all vessels ≥ 2 mm in diameter, not just those assessed by invasive FFR measurements. Stenoses <30% were assigned an FFR of 0.90, and stenoses >90% were assigned an FFR of 0.50. Diagnostic performance of FFRCT was stratified by vessel diameter, sex, and age. By FFR, ischemia was identified in 129 of 252 patients (51%) and in 151 of 407 vessels (31%). Mean age (± standard deviation) was 62.9 ± 9 years, and women were older (65.5 vs 61.9 years; P = .003). Per-patient diagnostic accuracy (83% vs 72%; P < .005) and specificity (54% vs 82%, P < .001) improved significantly after application of the clinical use tool. These were significantly improved over standard coronary CTA values before application of the clinical use rule. Discriminatory power of FFRCT also increased compared with baseline (area under the receiver operating characteristics curve [AUC]: 0.93 vs 0.81, P < .001). Diagnostic performance improved in both sexes with no significant differences between the sexes (AUC: 0.93 vs 0.90, P = .43). There were no differences in the discrimination of FFRCT after application of the clinical use rule when stratified by age ≥ 65 or <65 years (AUC: 0.95 vs 0.90, P = .10). The diagnostic accuracy and discriminatory power of FFRCT improve significantly after the application of a clinical use rule which includes all clinically relevant vessels >2 mm in diameter. FFRCT has similar diagnostic accuracy and discriminatory power for ischemia detection in men and women irrespective of age using a cut point of 65 years.

Thompson AG ，Raju R ，Blanke P ，Yang TH ，Mancini GB ，Budoff MJ ，Norgaard BL ，Min JK ，Leipsic JA ... -  《-》

Influence of Coronary Calcification on the Diagnostic Performance of CT Angiography Derived FFR in Coronary Artery Disease: A Substudy of the NXT Trial.

The goal of this study was to examine the diagnostic performance of noninvasive fractional flow reserve (FFR) derived from coronary computed tomography angiography (CTA) (FFRCT) in relation to coronary calcification severity. FFRCT has shown promising results in identifying lesion-specific ischemia. The extent to which the severity of coronary calcification affects the diagnostic performance of FFRCT is not known. Coronary calcification was assessed by using the Agatston score (AS) in 214 patients suspected of having coronary artery disease who underwent coronary CTA, FFRCT, and FFR (FFR examination was performed in 333 vessels). The diagnostic performance of FFRCT (≤0.80) in identifying vessel-specific ischemia (FFR ≤0.80) was investigated across AS quartiles (Q1 to Q4) and for discrimination of ischemia in patients and vessels with a low-mid AS (Q1 to Q3) versus a high AS (Q4). Coronary CTA stenosis was defined as lumen reduction >50%. Mean ± SD per-patient and per-vessel AS were 302 ± 468 (range 0 to 3,599) and 95 ± 172 (range 0 to 1,703), respectively. There was no statistical difference in diagnostic accuracy, sensitivity, or specificity of FFRCT across AS quartiles. Discrimination of ischemia by FFRCT was high in patients with a high AS (416 to 3,599) and a low-mid AS (0 to 415), with no difference in area under the receiver-operating characteristic curve (AUC) (0.86 [95% confidence interval (CI): 0.76 to 0.96] vs. 0.92 [95% CI: 0.88 to 0.96]) (p = 0.45). Similarly, discrimination of ischemia by FFRCT was high in vessels with a high AS (121 to 1,703) and a low-mid AS (0 to 120) (AUC: 0.91 [95% CI: 0.85 to 0.97] vs. 0.95 [95% CI: 0.91 to 0.98]; p = 0.65). Diagnostic accuracy and specificity of FFRCT were significantly higher than for stenosis assessment in each AS quartile at the per-patient (p < 0.001) and per-vessel (p < 0.05) level with similar sensitivity. In vessels with a high AS, FFRCT exhibited improved discrimination of ischemia compared with coronary CTA alone (AUC: 0.91 vs. 0.71; p = 0.004), whereas on a per-patient level, the difference did not reach statistical significance (AUC: 0.86 vs. 0.72; p = 0.09). FFRCT provided high and superior diagnostic performance compared with coronary CTA interpretation alone in patients and vessels with a high AS.

Nørgaard BL ，Gaur S ，Leipsic J ，Ito H ，Miyoshi T ，Park SJ ，Zvaigzne L ，Tzemos N ，Jensen JM ，Hansson N ，Ko B ，Bezerra H ，Christiansen EH ，Kaltoft A ，Lassen JF ，Bøtker HE ，Achenbach S ... -  《-》

CT angiography (CTA) and diagnostic performance of noninvasive fractional flow reserve: results from the Determination of Fractional Flow Reserve by Anatomic CTA (DeFACTO) study.

Leipsic J ，Yang TH ，Thompson A ，Koo BK ，Mancini GB ，Taylor C ，Budoff MJ ，Park HB ，Berman DS ，Min JK ... -  《-》

Noninvasive fractional flow reserve derived from computed tomography angiography for coronary lesions of intermediate stenosis severity: results from the DeFACTO study.

Nakazato R ，Park HB ，Berman DS ，Gransar H ，Koo BK ，Erglis A ，Lin FY ，Dunning AM ，Budoff MJ ，Malpeso J ，Leipsic J ，Min JK ... -  《-》

Diagnostic Performance of Transluminal Attenuation Gradient and Noninvasive Fractional Flow Reserve Derived from 320-Detector Row CT Angiography to Diagnose Hemodynamically Significant Coronary Stenosis: An NXT Substudy.

Ko BS ，Wong DT ，Nørgaard BL ，Leong DP ，Cameron JD ，Gaur S ，Marwan M ，Achenbach S ，Kuribayashi S ，Kimura T ，Meredith IT ，Seneviratne SK ... -  《-》