Coronary Angiography-derived Fractional Flow Reserve Research Articles

Complete revascularization based on angiography derived fractional flow reserve versus incomplete revascularization in patients with ST-segment elevation myocardial infarction.

Nearly half of ST-segment elevation myocardial infarction (STEMI) patients present with significant multivessel coronary artery disease, they are at high risk of subsequent adverse events. Whether complete revascularization guided by coronary angiography-derived fractional flow reserve (caFFR) further reduces such events risk is not fully investigated. In this study, 367 consecutive STEMI patients who underwent successful primary percutaneous coronary intervention (PCI) were enrolled. caFFR of all three coronary vessels were measured, including 367 culprit vessels and 703 non-culprit vessels. Complete revascularization was defined as post-PCI caFFR > 0.8 of all three coronary vessels. The primary endpoint was major adverse cardiovascular events (MACE, a composite of cardiovascular death, non-fatal recurrent myocardial infarction, ischemia-driven revascularization and non-fatal stroke/transient ischemic attacks) during follow-up. At a median follow-up of 3.8 years, MACE had occurred in 39 patients of the 220 (17.7%) in the complete revascularization group as compared with 49 patients of the 131 (37.4%) in the incomplete revascularization group (hazard ratio [HR] 1.9; 95% confidence interval [CI] 1.2-3.0; p = 0.005). The incomplete revascularization in culprit vessels evaluated by caFFR showed the highest risk for MACE occurrence. In STEMI patients with multivessel coronary artery disease, incomplete revascularization based on caFFR might contribute to identifying patients at high-risk.

Coronary Artery Tree Description and Lesion Evaluation (CatLet) score for functional evaluation of coronary stenosis: a comparison study with pressure wire fractional flow reserve.

Pressure wire fractional flow reserve (FFR) and its derivatives, such as quantitative flow ratio (QFR), computational pressure flow-derived FFR (caFFR), coronary angiography-derived FFR (FFRangio), and computed tomography-derived FFR (FFRCT), have been validated for identifying functionally significant stenosis and guiding revascularization strategy. The limitations of using these methods include the side effects of hyperemia-induced agents, additional costs, and vulnerability to microvascular resistance. FFR is related both to the degree of a stenotic coronary artery and to its subtended myocardial territory. Coronary Artery Tree Description and Lesion Evaluation (CatLet) score (also known as Hexu) is a product of the degree of a stenosis and the weighting of the affected coronary artery (myocardial territory). Hence, we hypothesized that the CatLet score could predict hemodynamically significant coronary stenosis. We retrospectively enrolled consecutive patients with stable coronary artery disease. They attended Sichuan Science City Hospital with at least one lesion of 50-90% diameter stenosis in a coronary artery of 2 mm or larger. FFR measurement was obtained during invasive coronary angiography. The CatLet score was obtained by multiplying a fixed value of 2.0 (for non-occlusive lesions) and the weight of the affected coronary artery. The primary endpoint was the CatLet score's diagnostic accuracy in identifying hemodynamically significant coronary stenosis, with a pressure wire FFR of ≤0.80 being used as reference. We analyzed the FFR and CatLet scores from 206 vessels in 175 patients with stable coronary disease and intermediate coronary lesions. The per-vessel analysis revealed an overall good correlation between the CatLet score and the FFR [r=-0.61; 95% confidence interval (95% CI): -0.69 to -0.52; P<0.01]. We also noted a significant CatLet score-FFR correlation for each of the left anterior descending artery (LAD), left circumflex (LCX), and right coronary artery (RCA). With a CatLet score ≥10 as a predictor of FFR ≤0.80, the overall diagnostic accuracy included a sensitivity of 78.80% (95% CI: 67.00-87.90%), a specificity of 85.00% (95% CI: 78.00-90.50%), a positive likelihood ratio of 5.25, a negative likelihood ratio of 0.25, and an area under the curve of 0.90 (95% CI: 0.85-0.94). Equivalent vessel-specific results were also achieved for each of the LAD, LCX, and RCA. The CatLet score, solely based on visual estimation of the results of coronary angiography, demonstrated good diagnostic performance with respect to myocardial ischemia. Its clinical values in guiding revascularization warrant further investigation.

Rationale and design of a comparison of angiography-derived fractional flow reserve-guided and intravascular ultrasound-guided intervention strategy for clinical outcomes in patients with coronary artery disease: a randomised controlled trial (FLAVOUR II)

IntroductionPercutaneous coronary intervention (PCI) guided by coronary angiography-derived fractional flow reserve (FFR) or intravascular ultrasound (IVUS) has shown improved clinical outcomes compared with angiography-only-guided PCI. In patients with intermediate stenoses,...

The prognostic value and economic benefits of coronary angiography-derived fractional flow reserve-guided strategy in patients with coronary artery disease

ObjectiveThis study aims to investigate the prognostic value and economic benefit of coronary angiography-derived fractional flow reserve (caFFR) guided percutaneous coronary intervention (PCI) in patients with coronary artery disease. MethodsAll patients with coronary artery disease (CAD) who underwent coronary angiography in our center between April 2021 and November 2021 were retrospectively enrolled and divided into the caFFR guidance group (n = 160) and angiography guidance group (n = 211). A threshold of caFFR≤0.8 was used for revascularization. Otherwise, delayed PCI was preferred. The patients were prospectively followed up by telephone or outpatient service at six months for major adverse cardiovascular events (MACE) of all-cause death, myocardial infarction or target vessel revascularization, stent thrombosis, and stroke. All in-hospital expenses were recorded, including initial hospitalization and re-hospitalization related to MACE. ResultsThere was no significant difference in the baseline characteristics between the two groups. There were 2 (1.2%) patients in the caFFR guidance group and 5 (2.4%) patients in the angiography guidance group with MACE events during the following six months. Compared with angiography guidance, caFFR guidance reduced the revascularization rate (63.7% vs. 84.4%, p = 0.000), the average length of stents implanted (0.52 ± 0.88 vs. 1.1 ± 1.4, P < 0.001). The cost of consumables in the caFFR guidance group was significantly lower than that in the angiography guidance group (33257 ± 19595 CNY vs. 38341 ± 16485 CNY, P < 0.05). ConclusionCompared with coronary angiography guidance, caFFR guidance is of great significance in reducing revascularization and cost, which has significant health and economic benefits.

Diagnostic performance of angiography-derived fractional flow reserve analysis based on bifurcation fractal law for assessing hemodynamic significance of coronary stenosis.

Blood flow into the side branch affects the calculation of coronary angiography-derived fractional flow reserve (FFR), called Angio-FFR. Neglecting or improperly compensating for the side branch flow may decrease the diagnostic accuracy of Angio-FFR. This study aims to evaluate the diagnostic accuracy of a novel Angio-FFR analysis that considers the side branch flow based on the bifurcation fractal law. A one-dimensional reduced-order model based on the vessel segment was used to perform Angio-FFR analysis. The main epicardial coronary artery was divided into several segments according to the bifurcation nodes. Side branch flow was quantified using the bifurcation fractal law to correct the blood flow in each vessel segment. In order to verify the diagnostic performance of our Angio-FFR analysis, two other computational methods were taken as control groups: (i) FFR_s: FFR calculated by delineating the coronary artery tree to consider side branch flow, (ii) FFR_n: FFR calculated by just delineating the main epicardial coronary artery and neglecting the side branch flow. The analysis of 159 vessels from 119 patients showed that our Anio-FFR calculation method had comparable diagnostic accuracy to FFR_s and provided significantly higher diagnostic accuracy than that of FFR_n. In addition, using invasive FFR as a reference, the Pearson correlation coefficients of Angio-FFR and FFRs were 0.92 and 0.91, respectively, while that of FFR_n was only 0.85. Our Angio-FFR analysis has demonstrated good diagnostic performance in assessing the hemodynamic significance of coronary stenosis by using the bifurcation fractal law to compensate for side branch flow. Bifurcation fractal law can be used to compensate for side branch flow during the Angio-FFR calculation of the main epicardial vessel. Compensating for side branch flow can improve the ability of Angio-FFR to diagnose stenosis functional severity. • The bifurcation fractal law could accurately estimate the blood flow from the proximal main vessel into the main branch, thus compensating for the side branch flow. • Angiography-derived FFR based on the bifurcation fractal law is feasible to evaluate the target diseased coronary artery without delineating the side branch.

Prognostic Value of Coronary Angiography-Derived Fractional Flow Reserve Immediately After Stenting.

ObjectivesThe aim of this study was to investigate the potential prognostic value of post-percutaneous coronary intervention (PCI) angiography-derived fractional flow reserve (FFR) and its gradient across the stent.BackgroundPost-PCI FFR and its gradient across the stent have been proved to be associated with clinical outcomes. However, little is known about the prognostic value of post-PCI coronary angiography-derived FFR and its gradient across the stent.MethodsPatients diagnosed with coronary heart disease and participated in drug-eluting stent (DES) clinical trials for stent implantation in a single center were included for this retrospective analysis. A novel coronary angiography-derived FFR (caFFR) and its gradient across the stent were calculated offline using two projections from coronary angiography performed after PCI. Clinical follow-up was completed at 9 months after the index procedure and the primary outcome was target vessel failure (TVF), defined as a composite of target vessel-related myocardial infarction (MI), target vessel-related revascularization (TVR), and cardiac death. Coronary angiography was also performed at the 9 months follow-up time to get data of late lumen loss (LLL) and percent diameter stenosis (%DS).ResultsA total of 159 vessels in 136 patients were analyzed. The mean value of post-PCI caFFR was 0.90 ± 0.06. The median value of trans-stent caFFR gradient (ΔcaFFRstent) was 0.04 (interquartile range 0.02–0.08). ΔcaFFRstent>0 was demonstrated in 147 vessels (92.45%). The TVF rate was significantly higher in patients with post-PCI caFFR < 0.90 (4 [8.16%] vs. 1 [1.15%], P = 0.037), which was mainly achieved by the difference between the TVR rate. In the subgroup with lesions located in the left anterior descending coronary artery (LAD), post-PCI caFFR was an independent predictor of LLL (β = −1.07, 95% CI: −1.74 to −0.39, P = 0.002) and %DS at follow-up (β = −30.24, 95% CI: −56.44 to −4.04, P = 0.025), ΔcaFFRstent was an independent predictor of LLL (β=0.98, 95% CI:0.13–1.83, P = 0.026).ConclusionSuboptimal post-PCI caFFR and trans-stent caFFR gradient were common among vessels immediately after stenting. Lower post-PCI caFFR was associated with a higher rate of 9-month TVF. After LAD PCI, both post-PCI caFFR and its gradient across stent were independent predictors of the neointimal proliferation of the target vessel evaluated by LLL and %DS at follow-up.

Lesion Length Improves Diagnostic Accuracy of Intravascular Ultrasound for Detecting Functional Intermediate Coronary Stenosis Evaluated With Coronary Angiography-Derived Fractional Flow Reserve in Non-left Main Artery.

Objective: Intravascular ultrasound (IVUS) parameters, for example, minimal lumen area (MLA) and area stenosis (AS), poorly identified functional intermediate coronary stenosis (ICS). For detecting functional ICS defined by coronary angiography-derived fractional flow reserve (caFFR), our study aims to determine whether IVUS parameters integrated with lesion length (LL) by three-dimensional quantitative coronary analysis (3D-QCA) could improve diagnostic value.Methods: A total of 111 patients with 122 ICS lesions in the non-left main artery were enrolled. MLA and AS were calculated in all lesions by IVUS. Diameter stenosis (DS%) and LL were measured by 3D-QCA. caFFR was computed by the proprietary fluid dynamic algorithm, a caFFR ≤ 0.8 was considered as functional stenosis. Receiver-operating curve analyses were used to compare the diagnostic accuracy among indices to predict functional stenoses.Results: Mean caFFR values in all lesions were 0.86 ± 0.09. Lesions with caFFR ≤ 0.8 showed lower MLA and higher AS (MLA: 3.3 ± 0.8 vs. 4.1 ± 1.2, P = 0.002; AS: 71.3 ± 9.6% vs. 63.5 ± 1.3%, P = 0.007). DS% and LL were more severe in lesions with caFFR ≤ 0.8 (DS%: 45.5 ± 9.6% vs. 35.5 ± 8.2%, P < 0.001; LL: 31.6 ± 12.9 vs. 21.0 ± 12.8, P < 0.001). caFFR were correlated with MLA, AS, and LL (MLA: r = 0.36, P < 0.001; AS: r = −0.36, P < 0.001; LL: r = −0.41, P < 0.001). Moreover, a multiple linear regression analysis demonstrated that MLA (β = 0.218, P = 0.013), AS (β = −0.197, P = 0.029), and LL (β = −0.306, P > 0.001) contributed significantly to the variation in caFFR. The best cutoff value of MLA, AS, and LL for predicting caFFR ≤ 0.8 were 3.6 mm2, 73%, and 26 mm, with area under the curve (AUC) of 0.714, 0.688, and 0.767, respectively. Combined with MLA, AS, and LL for identifying functional ICS, the accuracy was the highest among study methods (AUC: 0.845, P < 0.001), and was significantly higher than each single method (All P < 0.05).Conclusion: Lesion length can improve the diagnostic accuracy of IVUS-derived parameters for detecting functional ICS.

Real-world clinical and cost analysis of CT coronary angiography and CT coronary angiography-derived fractional flow reserve (FFRCT)-guided care in the National Health Service

To quantify the real-world clinical and cost impact of computed tomography (CT) coronary angiography (CTCA)-derived fractional flow reserve (FFRCT) in the National Health Service (NHS). Consecutive clinical CTCA examinations from September to December 2018 with ≥1 stenosis of ≥25% underwent FFRCT analysis. The Heart Team reviewed clinical data and CTCA findings, blinded to FFRCT values, and documented hypothetical consensus management. FFRCT results were then unblinded and hypothetical consensus management re-recorded. Diagnostic waiting times for management pathways were estimated. A per-patient cost analysis for diagnostic certainty regarding coronary artery disease (CAD) management was performed using 2014-2020 NHS tariffs for pre- and post-FFRCT pathways. Two hundred and fifty-one CTCAs were performed during the study period. Fifty-seven percent (145/251) had no CAD or stenosis <25%. One study was non-diagnostic. Of the remaining 42% (105/251), two were ineligible for FFRCT and there was a 5% (5/103) failure rate. FFRCT led to a change in hypothetical management in 65% (64/98; p<0.001) patients with a functional imaging test cancelled in 17% (17/98) and a diagnostic angiogram cancelled in 47% (46/98). FFRCT-guided management had a reduced mean time to definitive investigation compared with CTCA alone (28±4 versus 44±4 days; p=0.004). Using the proposed 2020/21 tariff, CTCA+FFRCT for stenosis ≥50% resulted in a diagnostic pathway £44.97 more expensive per patient than usual care without FFRCT. In the real-world NHS setting, FFRCT-guided management has the potential to rationalise patient management, accelerate diagnostic pathways, and depending on the stenosis severity modelled, may be cost-effective.

Agreement of Angiography-Derived and Wire-Based Fractional Flow Reserves in Percutaneous Coronary Intervention.

Background: Coronary angiography-derived fractional flow reserve (caFFR) measurements have shown good correlations and agreement with invasive wire-based fractional flow reserve (FFR) measurements. However, few studies have examined the diagnostic performance of caFFR measurements before and after percutaneous coronary intervention (PCI). This study sought to compare the diagnostic performance of caFFR measurements against wire-based FFR measurements in patients before and after PCI.Methods: Patients who underwent FFR-guided PCI were eligible for the acquisition of caFFR measurements. Offline caFFR measurements were performed by blinded hospital operators in a core laboratory. The primary endpoint was the vessel-oriented composite endpoint (VOCE), defined as a composite of vessel-related cardiovascular death, vessel-related myocardial infarction, and target vessel revascularization.Results: A total of 105 pre-PCI caFFR measurements and 65 post-PCI caFFR measurements were compared against available wire-based FFR measurements. A strong linear correlation was found between wire-based FFR and caFFR measurements (r = 0.77; p < 0.001) before PCI, and caFFR measurements also showed a high correlation (r = 0.82; p < 0.001) with wire-based FFR measurements after PCI. A total of 6 VOCEs were observed in 61 patients during follow-up. Post-PCI FFR values (≤0.82) in the target vessel was the strongest predictor of VOCE [hazard ratio (HR): 5.59; 95% confidence interval (CI): 1.12–27.96; p = 0.036). Similarly, patients with low post-PCI caFFR values (≤0.83) showed an 8-fold higher risk of VOCE than those with high post-PCI caFFR values (>0.83; HR: 8.83; 95% CI: 1.46–53.44; p = 0.017).Conclusion: The study showed that the caFFR measurements were well-correlated and in agreement with invasive wire-based FFR measurements before and after PCI. Similar to wire-based FFR measurements, post-PCI caFFR measurements can be used to identify patients with a higher risk for adverse events associated with PCI.

TCT-305 Comparison of 2D-QCA, 3D-QCA and coronary angiography derived FFR in predicting myocardial ischemia assessed by D-SPECT

Introduction: Coronary angiography derived fractional flow reserve (CAFFR) was proved to have an overall diagnostic accuracy of 85% compared to invasive FFR. The purpose of this study was to invest...