Author + information
- Received June 11, 2018
- Revision received September 3, 2018
- Accepted September 17, 2018
- Published online February 4, 2019.
- Taku Asano, MDa,b,
- Yuki Katagiri, MDa,
- Chun Chin Chang, MDc,
- Norihiro Kogame, MDa,
- Ply Chichareon, MDa,
- Kuniaki Takahashi, MDa,
- Rodrigo Modolo, MDa,
- Erhan Tenekecioglu, MDc,
- Carlos Collet, MDa,d,
- Hans Jonker, BSce,
- Clare Appleby, MDf,
- Azfar Zaman, MDg,
- Nicolas van Mieghem, MD, PhDc,
- Neal Uren, MDh,
- Javier Zueco, MDi,
- Jan J. Piek, MD, PhDa,
- Johan H.C. Reiber, MD, PhDj,
- Vasim Farooq, MD, PhDk,
- Javier Escaned, MD, PhDl,
- Adrian P. Banning, MDm,
- Patrick W. Serruys, MD, PhDc,∗ ( and )
- Yoshinobu Onuma, MD, PhDc,f
- aDepartment of Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- bDepartment of Cardiology, St. Luke’s International Hospital, Tokyo, Japan
- cThoraxCenter, Erasmus Medical Center, Rotterdam, the Netherlands
- dDepartment of Cardiology, Universitair Ziekenhuis Brussels, Brussels, Belgium
- eCardialysis, Rotterdam, the Netherlands
- fDepartment of Cardiology, Liverpool Heart and Chest Hospital, Liverpool, United Kingdom
- gDepartment of Cardiology, Freeman Hospital Newcastle, Newcastle upon Tyne, United Kingdom
- hDepartment of Cardiology, The Royal Infirmary of Edinburgh, Edinburgh, United Kingdom
- iDepartment of Cardiology, Hospital Universitario Valdecilla, Cantabria, Spain
- jDepartment of Radiology, Leiden University Medical Center, Leiden, the Netherlands
- kManchester Heart Centre, Manchester Royal Infirmary, Central Manchester University Hospitals, Manchester, United Kingdom
- lHospital Clinico San Carlos IDISSC and Universidad Complutense de Madrid, Madrid, Spain
- mDepartment of Cardiology, John Radcliffe Hospital, Cardiology, Oxford, United Kingdom
- ↵∗Address for correspondence:
Prof. Patrick W. Serruys, ThoraxCenter, Erasmus Medical Center, Westblaak 98, 3012 KM Rotterdam, the Netherlands.
Objectives The aims of the present study were to investigate the applicability of quantitative flow ratio (QFR) in patients with 3-vessel disease and to demonstrate the impact of functional SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score derived from QFR (fSSQFR) on clinical outcomes.
Background The applicability of QFR in patients with 3-vessel disease and the feasibility of fSSQFR have not yet been investigated.
Methods All lesions interrogated using instantaneous wave-free ratio and/or fractional flow reserve in the SYNTAX II trial were retrospectively screened and analyzed for QFR. The diagnostic performance of QFR was investigated using hybrid wire-derived pressure assessment (instantaneous wave-free ratio and fractional flow reserve), used in the trial as a reference. Patients with analyzable QFR in 3 vessels were stratified according to fSSQFR to evaluate its clinical prognostic value on the basis of 2-year patient-oriented composite endpoint.
Results QFRs were analyzable in 71.0% of lesions (836 lesions). The diagnostic performance of QFR to predict binary wire-based ischemia was substantial (area under the curve 0.81, accuracy 73.8%), with a positive predictive value of 85.9%. Independent predictors of diagnostic discordance were lesions in side branches, involvement of bifurcation or trifurcation, and small vessel. According to the 2-year patient-oriented composite endpoint, fSSQFR reclassified 26.1% of the patients (36 of 138) in the high- to intermediate-risk group into the low-risk group appropriately (net reclassification improvement 0.32; p < 0.001). The area under the curve for fSSQFR to predict the 2-year patient-oriented composite endpoint was higher than that of the classic anatomic SYNTAX score (0.68 vs. 0.56; p = 0.002).
Conclusions QFR demonstrated substantial applicability in patients with 3-vessel disease. The fSSQFR has the potential to further refine prognostic risk estimation compared with the classic anatomic SYNTAX score.
Ischemia-driven percutaneous coronary intervention (PCI) on the basis of the pressure-derived index of fractional flow reserve (FFR) has been associated with improved outcomes in several large clinical trials (1–3). PCI with the guidance of instantaneous wave-free ratio (iFR) demonstrated noninferiority to FFR-guided PCI with respect to the rate of major adverse cardiac events at 12 months in 2 large clinical trials (4,5). In the current European Society of Cardiology and American College of Cardiology/American Heart Association guidelines, pressure-derived physiological assessment of stenotic lesions is recommended (Class Ia) for decision making in revascularization (6,7).
The efficacy of PCI with the guidance of wire-derived pressure index for patients with 3-vessel disease (3VD) was demonstrated in the SYNTAX (Synergy Between PCI With Taxus and Cardiac Surgery II trial (8). The SYNTAX II trial was designed to compare the clinical efficacy of physiology-guided contemporary PCI in patients with 3VD with the state-of-art PCI including the current-generation drug-eluting stent (Synergy, Boston Scientific, Natick, Massachusetts) and intravascular ultrasound with the conventional PCI arm of the SYNTAX I trial (8,9). State-of-the-art PCI guided by hybrid physiological assessment comprising iFR and FFR reduced the number of lesions to treat and demonstrated improved clinical results at 12 months (composite of all-cause death, cerebrovascular event, any myocardial infarction, and any revascularization: 10.6% for SYNTAX II vs. 17.4% for SYNTAX I; hazard ratio: 0.58; 95% confidence interval [CI]: 0.39 to 0.85; p = 0.006) (8).
On the basis of 3-dimensional angiography, angiography-derived FFR (quantitative flow ratio [QFR]) is computed and results in virtual color-coded pull-backs of FFR of the angiographically imaged arteries with stenosis, without the use of a pressure wire or hyperemia (10,11). Several studies reported substantial correlation between QFR and wire-derived FFR in patients with coronary artery disease (10,12,13). Previous studies validating QFR included noncomplex anatomic lesions and patients (10,12,13). The applicability of QFR in patients with anatomically complex coronary artery disease, such as those with 3VD, has not yet been investigated.
It was reported that the functional SYNTAX score (fSS) derived from FFR, which was obtained by scoring only ischemia-provoking lesions on the basis of invasive FFR, has better discriminant ability for the risk for adverse events than the anatomic SYNTAX score alone (14).
The aims of the present study were to investigate the diagnostic performance of QFR in patients with 3VD using the wire-based physiological assessment as a reference and to demonstrate the impact of fSS derived from QFR (fSSQFR) on prognosis and clinical outcomes.
The present study was a post hoc substudy of the SYNTAX II trial to investigate the feasibility of physiological assessment with QFR in patients with 3VD and the impact of fSSQFR on prognosis and clinical outcomes. In the present study, all lesions interrogated with iFR and/or FFR in the SYNTAX II trial were screened and analyzed for QFR. In the patients with analyzable QFR of angiographic stenosis in the 3 vessels, fSS was calculated on the basis of QFR, and patients were stratified according to fSS to evaluate its clinical impact on the basis of 2-year clinical events.
Study design and hybrid wire-based physiological assessment of the SYNTAX II trial
The SYNTAX II trial is a multicenter, all-comers, open-label, single-arm study, enrolling patients with de novo 3VD without left main stem involvement (NCT02015832) (8). The study design has been described previously (15). The trial enrolled 454 patients with 1,559 anatomic target lesions at 22 interventional cardiology centers from 4 European countries, following the local heart team consensus with an equipoise recommendation between coronary artery bypass grafting and PCI on the basis of the SYNTAX score II, which is based on a combination of the anatomic SYNTAX score, clinical characteristics, and comorbidities (16). The trial was approved by the local ethics committee at all participating sites.
The enrolled patients were treated with contemporary PCI on the basis of the specific hybrid physiological assessment with iFR and FFR. The details of the specific physiological assessment are described in the Online Appendix and Online Figure 1. The iFR/FFR (Verrata and PrimeWire Prestige, Volcano, San Diego, California) was measured distal to each target lesion, and the site of iFR/FFR assessment was documented with angiography.
In the SYNTAX II trial, coronary angiography was performed prior to PCI for anatomic SYNTAX scoring but without specific acquisition guidelines for QFR analysis. Angiography was preceded by an intracoronary injection of isosorbide dinitrate or nitroglycerin.
In the trial, an independent clinical events committee adjudicated adverse events. To investigate the clinical impact of fSS, major adverse cardiac events (patient-oriented composite endpoint [POCE]) were defined as a composite of all-cause death, any myocardial infarction, or any revascularization. The definition of myocardial infarction used in the SYNTAX II trial has been described previously (8).
QFR analysis and angiographic parameters
All lesions with wire-based physiological assessment in the SYNTAX II trial were eligible for the present analysis. Lesions were excluded from the analysis if they: 1) were located <3 mm from the aorta; 2) had a reference luminal diameter <2.0 mm by visual assessment; 3) presented slow coronary blood flow (TIMI [Thrombolysis In Myocardial Infarction] flow grade 1 or 2); 4) were filmed with <2 projections with isocenter calibration information; 5) had severe vessel overlap at the stenotic segments; or 6) had poor angiographic image quality precluding precise contour delineation.
Off-line QFR analysis was performed by experienced analysts certified for use of the software with the QAngio XA 3D version 1.1 software package (Medis Medical Imaging Systems, Leiden, the Netherlands). For computation of QFR, contrast QFR without hyperemic setting along with the frame-counting method was applied. The analysts were blinded to iFR and FFR results. Details regarding the QFR calculation have been reported elsewhere (10,17). Briefly, the QFR calculation is based on the 3-dimensional quantitative coronary angiogram reconstructed from 2 angiographic projections with angles ≥25° apart and volumetric flow rate calculated by using contrast bolus frame count (10). The volumetric flow from the proximal to the distal part of the quantified segment of the coronary artery was assessed by the product of area and flow velocity on the basis of frame count as assessed using the previously reported method (18).
QFR was analyzed from the ostium of the main vessels (left anterior descending, right, and left circumflex coronary arteries) to the anatomic site where iFR and FFR were interrogated. Whenever the location of the iFR/FFR sensor was not identified, the endpoint of the analysis segment was set at a landmark (e.g., side branch) located distal to the lesion. The automatic reference interpolation function was used to establish the reference for the calculation. Whenever a proper reference-interpolated line could not be established, it was adjusted by using nondiseased proximal or distal segments. The cutoff value of QFR for physiological significance was defined as 0.80 (10).
Reference vessel diameter (RVD), lesion length, and percentage area stenosis were derived from the 3-dimensional quantitative coronary angiogram simultaneously analyzed with QFR in QAngio XA 3D (7).
fSSQFR and hybrid iFR and FFR assessment
The classic anatomic SYNTAX score (cSS) was calculated on site on the basis of a visual evaluation of significant lesions (diameter stenosis >50% in vessels ≥1.5 mm) and reported using an electronic case report form. An online calculator, Syntax Score version 2.28 (Syntax Score Working Group), was used to derive total and per lesion cSS.
In the present study, 2 fSS were calculated on the basis of both hybrid iFR/FFR and QFR assessment (14). The fSS derived from hybrid iFR and FFR assessment (fSSiFR/FFR) was calculated by summing the individual points of physiologically significant lesions and excluding physiologically nonsignificant lesions on the basis of the hybrid iFR and FFR assessment. In the case of sequential lesions, the iFR and FFR measured in the most distal segment of the vessel were used to assess the physiological significance of the sequential lesions (19). The scores from a total occlusion were included in the fSS calculation. The fSSQFR was calculated in a similar manner using QFR values. The scores from lesions in small vessels (<2.0 mm) were included in the fSS calculation, despite the unavailability of QFR measurement.
Data are expressed as mean ± SD or median (interquartile range). Categorical variables were compared using the Pearson chi-square test or Fisher exact test, as appropriate. Continuous variables were compared using the Student's t-test. Unless otherwise specified, a 2-sided p value <0.05 was considered to indicate statistical significance.
The levels of correlation and agreement between QFR and iFR were determined using the Pearson correlation coefficient, Passing-Bablok regression analysis, and the Bland-Altman method (20,21). The discrimination ability of QFR was quantified using the receiver-operating characteristic (ROC) curve and the area under the curve (AUC) was compared with percentage area stenosis by using the DeLong method (22). For a reference, a positive test outcome of wire-based physiological assessment was defined as iFR <0.86 or FFR ≤0.8, and a negative test outcome was defined as iFR >0.93 or FFR >0.8 (Online Figure 1).
As an ancillary analyses, to assess the predictors of diagnostic discordance between QFR and hybrid iFR and FFR assessment (QFR false positive or QFR false negative), multivariate logistic regression analysis was conducted. The detailed methodology is described in the Online Appendix.
The prediction capability of cSS and fSS for the 2-year POCE was assessed using ROC curve analysis with AUC. The risk reclassification of the SYNTAX score terciles from the classic anatomic model to the functional model was assessed using the net reclassification index comparing the predictive accuracy of the cSS and fSS for the POCE during 2-year follow-up (23). Agreement of the classification according to the tertiles between fSSQFR and fSSiFR/FFR was assessed using Cohen’s kappa.
All statistical analyses were performed using R version 3.4 (R Foundation for Statistical Computing, Vienna, Austria) and SPSS version 24.0 (IBM, Armonk, New York).
In the SYNTAX II trial, 447 patients with 1,177 lesions were interrogated with iFR or FFR (only iFR performed, 840 lesions; iFR and FFR performed, 310 lesions; only FFR performed, 27 lesions). Among those lesions, QFR was analyzable in 836 lesions (analyzability 71.0%). In 386 patients (86.3%), QFR was analyzable in at least 1 lesion, whereas in 109 patients (28.2%), QFR was analyzable in angiographic anatomic stenoses in 3 vessels. QFR was not analyzable in 341 lesions, mainly because of the absence of 2 appropriate projections (severe vessel overlaps or tortuosity at lesion, and so on) (Figure 1). The baseline characteristics of the study population are shown in Tables 1 and 2⇓⇓.
Median QFR was 0.78 (IQR: 0.66 to 0.88; n = 836), and median iFR and FFR were 0.84 (IQR: 0.69 to 0.93; n = 817) and 0.78 (IQR: 0.73 to 0.84; n = 181), respectively (Table 3). The distribution of QFR and iFR is shown in Online Figure 2.
Correlation between iFR and QFR
The correlation between iFR and QFR is shown in Online Figure 3. In the Passing-Bablok linear regression analysis, there were no systematic or proportional differences between QFR and iFR (slope 1.00 [95% CI: 0.89 to 1.14], intercept 0.05 [95% CI: −0.07 to 0.14]), respectively. The details of the results are shown and discussed in the Online Appendix, Online Figure 4.
Diagnostic performance of QFR against binary physiological assessment with hybrid iFR/FFR approach
In the ROC curve analysis, the AUC for QFR predicting significant ischemia using the hybrid wire-based approach was 0.81 (95% CI: 0.78 to 0.84), and the AUC of percentage area stenosis was 0.73 (95% CI: 0.69 to 0.76) (difference 0.08; 95% CI: 0.05 to 0.11; p < 0.001) (Figure 2).
The diagnostic accuracy of QFR against hybrid wire-based physiologic assessment was 73.8% (95% CI: 70.6% to 76.8%), and the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of QFR were 73.7% (95% CI: 69.8% to 77.4%), 73.9% (95% CI: 68.1% to 79.2%), 85.9% (95% CI: 82.4% to 88.9%), and 56.7% (95% CI: 51.2% to 62.1%), respectively (Figure 3). There were 212 lesions (26.2%) with discordant diagnosis between QFR and hybrid iFR and FFR assessment (false positive 8.3% [67 of 809], false negative 17.9% [145 of 809]).
Sensitivity analysis was performed using iFR with a cutoff value of 0.89 as a reference (n = 817). This analysis showed a similar AUC of 0.80 (95% CI: 0.77 to 0.83), with accuracy of 72.9% (95% CI: 69.8% to 76.0%), sensitivity of 74.6% (95% CI: 70.6% to 78.2%), specificity of 70.1% (95% CI: 64.5% to 75.2%), PPV of 81.6% (95% CI: 77.8% to 85.0%), and NPV of 60.8% (95% CI: 55.3% to 66.0%).
In logistic regression analyses, lesion location in side branches (segments 4, 16, 9, 10, 12, and 14) was an independent predictor if false-positive QFR, with an odds ratio of 2.07 (95% CI: 1.14 to 3.76), and small vessel (RVD ≤2.25 mm) and bifurcation or trifurcation were independent predictors of increased incidence of false-negative QFR, with odds ratios of 1.67 (95% CI: 1.14 to 2.44) and 1.81 (95% CI: 1.10 to 2.98) (Online Table 1). Stratified analyses according to lesion characteristics assessing the diagnostic performance of QFR are shown and discussed in the Online Appendix, Online Figures 5 and 6.
Functional SYNTAX score derived from QFR and hybrid iFR/FFR assessment
In 138 patients (35.8%), fSS was analyzable with both methodologies (fSSiFR/FFR and fSSQFR). The patient flow for fSS calculation is presented in Online Figure 7. In those patients, cSS was 19.5 ± 5.6, while fSSQFR and fSSiFR/FFR were reduced to 14.8 ± 7.0 and 16.0 ± 6.5, respectively. A representative case of fSS calculation on the basis of QFR is shown in Figure 4.
Risk classification of patients was performed according to tertiles of cSS (<17, low-risk group; 17 to 22, intermediate-risk group; >22, high-risk group). After the calculation of fSS (fSSQFR and fSSiFR/FFR), 26.1% of patients were reclassified from the high- or intermediate-risk group into the low-risk group by QFR, and 20.3% of patients were reclassified into the low-risk group by iFR/FFR (Figure 5). Substantial agreement of the risk classification on the basis of fSSQFR with that based on fSSiFR/FFR was observed (kappa = 0.740).
Impact of fSSQFR and fSSiFR/FFR on 2-year clinical endpoints
The median follow-up duration was 788 days (IQR: 738 to 1,098 days). The incidence of the 2-year POCE stratified according to SYNTAX score tercile (cSS, fSSQFR, and fSSiFR/FFR) is presented in Figure 6. In the classification according to cSS, the POCE occurred 4.4%, 9.8%, and 9.5% of patients in the low-, intermediate-, and high-risk groups, respectively, at 2 years (p = 0.57, chi-square test). Regarding fSS, POCE rates were 3.7%, 11.0%, and 19.0% of patients in the low-, intermediate-, and high-risk groups with fSSQFR, respectively (p = 0.05, chi-square test) whereas POCE rates were 4.1%, 9.5%, and 17.0% of patients in the low-, intermediate-, and high-risk groups stratified by fSSiFR/FFR (p = 0.11, chi-square test).
The reclassification table with the incidence of the 2-year POCE is presented in Table 4. Both fSSQFR and fSSiFR/FFR yielded significantly improved risk classification compared with cSS (net reclassification index for fSSQFR 0.32 [95% CI: 0.24 to 0.40; p < 0.001], net reclassification index for fSSiFR/FFR 0.19 [95% CI: 0.01 to 0.34; p = 0.004).
The ROC curves for cSS, fSSQFR, and fSSiFR/FFR are shown with AUCs predicting the 2-year POCE in Figure 7. The AUC of fSSQFR was significantly greater than that of cSS (0.68 [95% CI: 0.50 to 0.87] for fSSQFR, 0.56 [95% CI: 0.37 to 0.75] for cSS; p = 0.002). A similar trend was observed in the comparison of AUCs between fSSiFR/FFR and cSS, although the difference was not statistically significant (0.62 [95% CI: 0.42 to 0.82] for fSSiFR/FFR, 0.56 [95% CI: 0.37 to 0.75] for cSS; p = 0.159).
In this post hoc substudy of the SYNTAX II trial investigating the feasibility and diagnostic performance of QFR in patients with 3VD and the impact of fSSQFR, the main findings are summarized as follows: 1) QFR was analyzable in 71.0% of lesions, while per-patient-level QFR analysis of all angiographic stenoses in the 3 vessels was feasible in 28.2% of patients; 2) the diagnostic performance of QFR to predict binary wire-based ischemia was substantial (AUC 0.81), with a PPV of 85.9%; 3) independent predictors of diagnostic discordance were lesions in side branches, involvement of bifurcation or trifurcation, and small vessel (RVD ≤2.25 mm); and 4) according to the 2-year POCE, fSSQFR appropriately reclassified high-risk patients to lower categories.
Feasibility of QFR in patients with 3VD
In the present study, QFR demonstrated acceptable lesion analyzability. However, without specific acquisition guidelines, analyzability of the entire coronary tree by QFR was as low as 28.1% of patients. The major reasons for nonanalyzable QFRs were the lack of 2 appropriate projections and the analysis of small vessels with RVDs <2 mm. How analyzability will be improved by the implementation of specific guidelines for angiographic acquisition should be investigated.
Diagnostic performance of QFR in patients with 3VD and factors affecting diagnostic discordance
In the present study in patients with 3VD, substantial diagnostic performance of QFR was observed, with a high PPV (AUC 0.81, PPV 85.9%). The prognostic value of QFR in patients with 3VD may have a considerable impact on the treatment decision.
However, in the present study, the overall NPV was low (56.7%). In the logistic regression analysis, independent factors for false negatives were small vessels (≤2.25 mm) and involvement of bifurcation or trifurcation (odds ratios: 1.67 [95% CI: 1.14 to 2.44] and 1.81 [95% CI: 1.10 to 2.98], respectively). In those lesions with small vessels or bifurcation or trifurcation, the NPV of QFR was 42.1% (95% CI: 33.9% to 50.8%). The limited diagnostic performance of QFR in those lesions should be acknowledged.
Risk reclassification by fSSQFR
In the present study, fSSQFR yielded a significant improvement in risk classification (0.32; 95% CI: 0.24 to 0.40; p < 0.001) as well as fSSiFR/FFR (0.19; 95% CI: 0.01 to 0.34; p = 0.004). The AUC of fSSQFR predicting the 2-year POCE was greater than that of cSS (0.68 for fSSQFR and 0.56 for cSS; p = 0.002). These results suggest that risk classification based on cSS in patients with 3VD can be properly reclassified by using QFR.
Risk assessment of patients with 3VD is of paramount important because the assessment influences heart team decision making, such as whether to perform PCI or surgical treatment (16,24). Physiological assessment before revascularization can alter not only treatment selection between PCI or surgery but also the number of treated lesions in patients with multivessel disease. In the total population of the SYNTAX II trial (n = 454), pressure wire–based physiological interrogation of the 3 coronary vessels, performed in 82.8% of the patients, reduced the number of 3-vessel interventions to 37.2% (8).
However, physiological assessment with a pressure wire has several limitations, such as cost, time, and related complications. Angiography-derived FFR potentially reduces these limitations. In the FAVOR Europe-Japan trial, prospectively investigating the feasibility and diagnostic performance of online QFR, the procedure time for QFR assessment was shorter than that for FFR with intravenous or intracoronary adenosine (5.0 min [IQR: 3.5 to 6.1 min] for QFR vs. 7.0 min [IQR: 5.0 to 10.0 min]; p < 0.001) (25). When QFR is applied to functional assessment of multiple vessels for risk assessment of a patient, the advantage of angiography-derived functional assessment may be enhanced with fewer complications, lower cost, and short procedure time.
Furthermore, the residual SYNTAX score after PCI was reported to have a substantial impact on long-term clinical outcome (26). The improved discriminant capability of the residual “functional” SYNTAX score on the basis of FFR for clinical outcome was reported in comparison with anatomic or physiological assessment alone (27). The prognostic value of the residual SYNTAX score combined with functional assessment on the basis of angiography-derived physiological index will be investigated in future studies.
The present study was a retrospective and non-pre-specified analysis. The angiography was not prospectively acquired according to specific acquisition protocol to fulfill the technical requirement of QFR analysis. The iFR/FFR measurement site, which was used for the endpoint of QFR analysis, was filmed only in 59.0%, which could be cause of the discrepancy between QFR and iFR/FR because of anatomic mismatch.
In the present analysis, investigating patients with 3VD without acquisition guideline, the feasibility of QFR was achieved in 71% of lesions and in 28.2% of these patients (feasible in the entire coronary tree). QFR demonstrated substantial diagnostic performance with high PPV, but low NPV was observed, especially for lesions in small vessels (RVD ≤2.25 mm) and bifurcation or trifurcation. The fSSQFR has the potential to further refine prognostic risk estimation in a less invasive fashion.
WHAT IS KNOWN? Functional assessment refines the prognostic value of the SYNTAX score only on the basis of anatomic information in patients with 3VD. QFR is a novel angiography-derived and therefore less invasive functional index that has demonstrated substantial diagnostic accuracy with FFR as a reference in patients with relatively simple lesions.
WHAT IS NEW? This is the first study investigating the diagnostic performance of QFR compared with iFR in patients with 3VD and the impact of the fSSQFR on clinical events. According to the results of the present study, QFR yielded substantial diagnostic accuracy in those patients, although diagnostic performance was impaired in bifurcated and trifurcated lesions or lesions in small vessels. The fSSQFR improved risk classification for the 2-year POCE compared with the cSS.
WHAT IS NEXT? Risk assessment using QFR may influence the treatment decision for patients with 3VD. It is warranted to investigate the impact of the fSSQFR on the treatment decision of a heart team for patients with 3VD using angiographic acquisition guidelines for QFR.
Dr. Reiber is the CEO of Medis Medical Imaging Systems and has a part-time appointment at Leiden University Medical Center as professor of medical imaging. Dr. Escaned is a consultant for Philips/Volcano and Boston Scientific. Dr. Banning receives lecture fees and grant support from Boston Scientific. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Abbreviations and Acronyms
- 3-vessel disease
- area under the curve
- confidence interval
- classic anatomic SYNTAX score(s)
- fractional flow reserve
- functional SYNTAX score(s)
- functional SYNTAX score derived from hybrid instantaneous wave-free ratio and fractional flow reserve assessment
- functional SYNTAX score derived from quantitative flow ratio
- instantaneous wave-free ratio
- interquartile range
- negative predictive value
- percutaneous coronary intervention
- patient-oriented composite endpoint
- positive predictive value
- quantitative flow ratio
- receiver-operating characteristic
- reference vessel diameter
- Received June 11, 2018.
- Revision received September 3, 2018.
- Accepted September 17, 2018.
- 2019 American College of Cardiology Foundation
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