Comparison of diagnostic performance in on-site based CT-derived fractional flow reserve measurements

Abstract

Background Computed tomography fractional flow reserve (CT-FFR), which can be acquired on-site workstation using fluid structure interaction during the multiple optimal diastolic phase, has an incremental diagnostic value over conventional coronary computed tomography angiography (CCTA). However, the appropriate location for CT-FFR measurement remains to be clarified. Method A total of 115 consecutive patients with 149 vessels who underwent CCTA showing 30–90% stenosis with invasive FFR within 90 days were retrospectively analyzed. CT-FFR values were measured at three points: 1 and 2 cm distal to the target lesion (CT-FFR 1cm, 2cm ) and the vessel terminus (CT-FFR lowest ). The diagnostic accuracies of CT-FFR ≤ 0.80 for detecting hemodynamically significant stenosis, defined as invasive FFR ≤ 0.80, were compered. Result Fifty-five vessels (36.9%) had invasive FFR ≤ 0.80. The accuracy and AUC for CT-FFR 1cm and 2cm were comparable, while the AUC for CT-FFR lowest was significantly lower than CT-FFR 1cm and 2cm . (lowest/1cm, 2 cm = 0.68 (95 %CI 0.63–0.73) vs 0.79 (0.72–0.86, p = 0.006), 0.80 (0.73–0.87, p = 0.002)) The sensitivity and negative predictive value of CT-FFR lowest were 100%. The reclassification rates from positive CT-FFR lowest to negative CT-FFR 1cm and 2cm were 55.7% and 54.2%, respectively. Conclusion The diagnostic performance of CT-FFR was comparable when measured at 1-to-2 cm distal to the target lesion, but significantly higher than CT-FFR lowest . The lesion-specific CT-FFR could reclassify false positive cases in patients with positive CT-FFR lowest , while all patients with negative CT-FFR lowest were diagnosed as negative by invasive FFR.

Prognostic value of the optimal measurement location of on-site CT-derived fractional flow reserve

“…The next challenge facing CT-FFR is the identification of an ideal position for simple and singular CT-FFR evaluations of CAD. We previously demonstrated that CT-FFR measured 1 to 2 cm distal to a target stenosis more strongly correlated with the result of invasive FFR than that measured at the vessel terminus [9]. However, the clinical utility and outcome data of optimal CT-FFR measurements have not yet been examined.…”

Detecting lesion-specific ischemia in patients with coronary artery disease with computed tomography fractional flow reserve measured at different sites

“…In another study by Omori et al, the diagnostic performance of FFR CT measured at 1 to 2 cm distal to the stenosis was also found to be higher than that of FFR CT -lowest (0.86 vs. 0.80, p = 0.002) in identifying lesion-speci c ischemia using invasive FFR as reference standard (15) . In addition, Nozaki et al (23) showed that the AUC of FFR CT -2cm was higher than that of FFR CT -lowest (0.80 vs. 0.68, p = 0.002) in identifying lesion-speci c ischemia and was comparable with that of FFR CT -1cm (0.80 vs. 0.79, p = 0.73). Based on these results, FFR CT measured at 1-to-2 cm distal to the stenosis is better than FFR CT -lowest in identifying lesion-speci c ischemia in patients with CAD.…”

“…Indeed, the invasive FFR was measured 2 to 3 cm distal to the target lesion in our study which is based on the recommendation as previously described (18) . Nonetheless, Omori et al (15) used invasive FFR measured 2-4 cm distal to the target lesion as the reference standard, and Nozaki et al (23) used invasive FFR measured distal to the stenosis as far as possible as the reference standard. As regards the target lesion, the de nition of the target lesion of a serial lesion in the study by Nozaki et al (23) was similar to our study, i.e., the most distal lesion in the vessel with 30%-90% diameter stenosis selected as the target lesion.…”

“…Nonetheless, Omori et al (15) used invasive FFR measured 2-4 cm distal to the target lesion as the reference standard, and Nozaki et al (23) used invasive FFR measured distal to the stenosis as far as possible as the reference standard. As regards the target lesion, the de nition of the target lesion of a serial lesion in the study by Nozaki et al (23) was similar to our study, i.e., the most distal lesion in the vessel with 30%-90% diameter stenosis selected as the target lesion. However, Omori et al (15) selected the most severe stenosis in serial lesion as target lesion.…”

Combined Coronary CT-Angiography and TAVI Planning: Utility of CT-FFR in Patients with Morphologically Ruled-Out Obstructive Coronary Artery Disease

“…Two previous studies have compared minimal CT-FFR measurements and measurements taken 2 cm distal to the lesion of interest. CT-FFR readings taken 2 cm distal to the lesion reduced the false positive rate by 44% and 54% with the same threshold, respectively [ 30 , 31 ]. While increased coronary artery resistance may be a product of diffuse atherosclerosis in the absence of obstructive CAD [ 32 ], we do not believe this to be the explanation for the majority of abnormal CT-FFR readings in our study cohort.…”