Yuetsu Kikuta

Use of the Instantaneous Wave-free Ratio or Fractional Flow Reserve in PCI

Background Coronary revascularization guided by fractional flow reserve (FFR) is associated with better patient outcomes after the procedure than revascularization guided by angiography alone. It is unknown whether the instantaneous wave‐free ratio (iFR), an alternative measure that does not require the administration of adenosine, will offer benefits similar to those of FFR. Methods We randomly assigned 2492 patients with coronary artery disease, in a 1:1 ratio, to undergo either iFR‐guided or FFR‐guided coronary revascularization. The primary end point was the 1‐year risk of major adverse cardiac events, which were a composite of death from any cause, nonfatal myocardial infarction, or unplanned revascularization. The trial was designed to show the noninferiority of iFR to FFR, with a margin of 3.4 percentage points for the difference in risk. Results At 1 year, the primary end point had occurred in 78 of 1148 patients (6.8%) in the iFR group and in 83 of 1182 patients (7.0%) in the FFR group (difference in risk, ‐0.2 percentage points; 95% confidence interval [CI], ‐2.3 to 1.8; P<0.001 for noninferiority; hazard ratio, 0.95; 95% CI, 0.68 to 1.33; P=0.78). The risk of each component of the primary end point and of death from cardiovascular or noncardiovascular causes did not differ significantly between the groups. The number of patients who had adverse procedural symptoms and clinical signs was significantly lower in the iFR group than in the FFR group (39 patients [3.1%] vs. 385 patients [30.8%], P<0.001), and the median procedural time was significantly shorter (40.5 minutes vs. 45.0 minutes, P=0.001). Conclusions Coronary revascularization guided by iFR was noninferior to revascularization guided by FFR with respect to the risk of major adverse cardiac events at 1 year. The rate of adverse procedural signs and symptoms was lower and the procedural time was shorter with iFR than with FFR. (Funded by Philips Volcano; DEFINE‐FLAIR ClinicalTrials.gov number, NCT02053038.)

Diagnostic Accuracy of Computed Tomography–Derived Fractional Flow Reserve: A Systematic Review

Importance Computed tomography–derived fractional flow reserve (FFR-CT) is a novel, noninvasive test for myocardial ischemia. Clinicians using FFR-CT must be able to interpret individual FFR-CT results to determine subsequent patient care. Objective To provide clinicians a means of interpreting individual FFR-CT results with respect to the range of invasive FFRs that this interpretation might likely represent. Evidence Review We performed a systematic review in accordance with guidelines from the Preferred Reporting Items for Systematic Reviews and Meta-Analyses. A systematic search of MEDLINE (January 1, 2011, to 2016, week 2) and EMBASE (January 1, 2011, to 2016, week 2) was performed for studies assessing the diagnostic accuracy of FFR-CT. Title words used were computed tomography or computed tomographic and fractional flow reserve or FFR. Results were limited to publications in peer-reviewed journals. Duplicate studies and abstracts from scientific meetings were removed. All of the retrieved studies, including references, were reviewed. Findings There were 908 vessels from 536 patients in 5 studies included in the analysis. A total of 365 (68.1%) were male, and the mean (SD) age was 63.2 (9.5) years. The overall per-vessel diagnostic accuracy of FFR-CT was 81.9% (95% CI, 79.4%-84.4%). For vessels with FFR-CT values below 0.60, 0.60 to 0.70, 0.70 to 0.80, 0.80 to 0.90, and above 0.90, diagnostic accuracy of FFR-CT was 86.4% (95% CI, 78.0%-94.0%), 74.7% (95% CI, 71.9%-77.5%), 46.1% (95% CI, 42.9%-49.3%), 87.3% (95% CI, 85.1%-89.5%), and 97.9% (95% CI, 97.9%-98.8%), respectively. The 82% (overall) diagnostic accuracy threshold was met for FFR-CT values lower than 0.63 or above 0.83. More stringent 95% and 98% diagnostic accuracy thresholds were met for FFR-CT values lower than 0.53 or above 0.93 and lower than 0.47 or above 0.99, respectively. Conclusions and Relevance The diagnostic accuracy of FFR-CT varies markedly across the spectrum of disease. This analysis allows clinicians to interpret the diagnostic accuracy of individual FFR-CT results. In combination with patient-specific factors, clinicians can use FFR-CT to judge when the cost and risk of an invasive angiogram may safely be avoided.

Impact of combined supine and prone myocardial perfusion imaging using an ultrafast cardiac gamma camera for detection of inferolateral coronary artery disease.

BACKGROUND Although combined supine and prone acquisitions improve the detection of inferolateral obstructive coronary artery disease (CAD), the predictors of inaccurate detection of inferolateral ischemia have not been reported by using cadmium zinc telluride (CZT) myocardial perfusion imaging (MPI). METHODS AND RESULTS Vasodilator stress (99m)Tc tetrofosmin MPI using CZT camera and coronary angiography was performed in 322 patients within an interval of 2 months. Prone MPI was performed immediately after supine MPI. Narrowing of the luminal diameter ≥ 75% was considered significant. The presence of an abnormality on both supine and prone images was considered significant. Combined supine and prone imaging, compared with supine-only quantification, was more specific (93% vs. 72%, respectively, p<0.0001) and accurate (88% vs. 74%, p<0.0001) without compromising sensitivity (82% vs. 68%, p=0.10). The area under the curve for detecting inferolateral ischemia was 0.769 (95% CI 0.705-0.833) for supine imaging and 0.802 (95% CI 0.730-0.875) for combined supine and prone imaging (p<0.05). Multivariable analysis revealed that previous inferolateral myocardial infarction was an independent predictor of a false diagnosis (odds ratio=3.45, 95% confidence interval [CI] 1.62-7.37, p<0.001). CONCLUSIONS Combined supine and prone quantitative CZT MPI enhances the detection of inferolateral CAD without adversely affecting its sensitivity. However, we recommend inferolateral ischemia be monitored in patients with a history of previous inferolateral MI because previous inferolateral MI is a predictor of inaccurate diagnosis.

Appearance of neointima according to stent type and restenotic phase: analysis by optical coherence tomography

AIMS The features of neointima after bare metal stent (BMS) or drug-eluting stent (DES) implantation have not yet been fully characterised. The aim of this study was to investigate in-stent neointima characteristics according to stent type and restenotic phase. METHODS AND RESULTS The study included 59 consecutive patients undergoing target lesion revascularisation for in-stent restenosis (ISR) evaluated by optical coherence tomography (OCT) during the early phase (≤1 year, n=30) and late phase (>1 year, n=29) after either BMS (n=37) or DES (n=22) implantation. The OCT signal patterns of tissues at the minimal lumen area were categorised into three patterns: (1) homogeneous high-signal band, (2) heterogeneous mixed-signal band, and (3) lipid-laden intima. The predominant OCT pattern was homogeneous high-signal band in the BMS early phase (19/21 [91%]), lipid-laden intima in the BMS late phase (12/16 [76%]), and heterogeneous mixed-signal band in the DES late phase (9/13 [69%]). Heterogeneous mixed-signal band was seen more frequently in the DES early phase compared with BMS early phase (44% vs. 9%, p<0.05). CONCLUSIONS There were differences of neointima according to stent type and restenotic phase, and this may lead to a better understanding of the different mechanisms of ISR.

Fractional Flow Reserve/Instantaneous Wave-Free Ratio Discordance in Angiographically Intermediate Coronary Stenoses: An Analysis Using Doppler-Derived Coronary Flow Measurements

Objectives The study sought to determine the coronary flow characteristics of angiographically intermediate stenoses classified as discordant by fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR). Background Discordance between FFR and iFR occurs in up to 20% of cases. No comparisons have been reported between the coronary flow characteristics of FFR/iFR discordant and angiographically unobstructed vessels. Methods Baseline and hyperemic coronary flow velocity and coronary flow reserve (CFR) were compared across 5 vessel groups: FFR+/iFR+ (108 vessels, n = 91), FFR–/iFR+ (28 vessels, n = 24), FFR+/iFR– (22 vessels, n = 22), FFR–/iFR– (208 vessels, n = 154), and an unobstructed vessel group (201 vessels, n = 153), in a post hoc analysis of the largest combined pressure and Doppler flow velocity registry (IDEAL [Iberian-Dutch-English] collaborators study). Results FFR disagreed with iFR in 14% (50 of 366). Baseline flow velocity was similar across all 5 vessel groups, including the unobstructed vessel group (p = 0.34 for variance). In FFR+/iFR– discordants, hyperemic flow velocity and CFR were similar to both FFR–/iFR– and unobstructed groups; 37.6 (interquartile range [IQR]: 26.1 to 50.4) cm/s vs. 40.0 [IQR: 29.7 to 52.3] cm/s and 42.2 [IQR: 33.8 to 53.2] cm/s and CFR 2.36 [IQR: 1.93 to 2.81] vs. 2.41 [IQR: 1.84 to 2.94] and 2.50 [IQR: 2.11 to 3.17], respectively (p > 0.05 for all). In FFR–/iFR+ discordants, hyperemic flow velocity, and CFR were similar to the FFR+/iFR+ group; 28.2 (IQR: 20.5 to 39.7) cm/s versus 23.5 (IQR: 16.4 to 34.9) cm/s and CFR 1.44 (IQR: 1.29 to 1.85) versus 1.39 (IQR: 1.06 to 1.88), respectively (p > 0.05 for all). Conclusions FFR/iFR disagreement was explained by differences in hyperemic coronary flow velocity. Furthermore, coronary stenoses classified as FFR+/iFR– demonstrated similar coronary flow characteristics to angiographically unobstructed vessels.

Calcification analysis by intravascular ultrasound to define a predictor of left circumflex narrowing after cross-over stenting for unprotected left main bifurcation lesions

OBJECTIVES The aim of this study was to identify predictors of significant LCx-ostium compromise after distal unprotected left main coronary artery (ULMCA) stenting on the basis of baseline intravascular ultrasound (IVUS). BACKGROUND Provisional single-stenting is considered as the default strategy for non-true bifurcation lesions in ULMCA. However, in certain cases, left circumflex artery (LCx)-ostium stenting is necessary. METHODS A total of 77 patients underwent percutaneous coronary intervention with drug-eluting stents for non-true bifurcation lesions in ULMCA and had IVUS evaluation. Pre-procedural IVUS was performed to measure cross-sectional areas at the following segments: left main trunk, left anterior descending artery (LAD)-ostium. Post-stenting-narrowing at the circumflex ostium (PSN-LCx) was defined as the presence of more than 50% diameter stenosis at the LCx-ostium as determined by quantitative coronary angiography analysis. RESULTS PSN-LCx occurred in 27 (35%) patients. The presence of calcified plaque at the culprit lesion as identified by IVUS was more frequently observed in the PSN-LCx group as compared to the non-PSN-LCx group (81.5% vs. 22.0%, p<0.001). Calcium arc in the PSN-LCx group was significantly greater than that in the non-PSN-LCx group (118.1°±69.9° vs. 36.9°±63.0°, p<0.001). On multivariable analysis, a calcium arc>60° was an independent predictor of PSN-LCx (odds ratio: 5.12, 95% confidence interval: 1.21-25.01, p=0.03). CONCLUSIONS The presence of calcified plaque at the culprit lesion appears to be one of the factors involved in LCx-ostial compromise in non-true bifurcation ULMCA lesions, especially when the calcium arc is >60°.

Acute Myocardial Infarction Caused by Left Main Coronary Artery Compression as a Result of a Mycotic Aneurysm of the Sinus of Valsalva.

An 83-year-old woman with a history of fever presented with severe chest pain progressing to cardiogenic shock. Her electrocardiogram showed evidence of anteroseptal myocardial infarction (MI). Urgent coronary angiography, with intra-aortic balloon pump support, indicated total occlusion of the left

The role of integrated backscatter intravascular ultrasound in characterizing bare metal and drug-eluting stent restenotic neointima as compared to optical coherence tomography.

BACKGROUND To evaluate the role of integrated backscatter intravascular ultrasound (IB-IVUS) in assessing the morphology of neointima in bare-metal stent (BMS) and drug-eluting stent (DES) restenosis as compared to the gold-standard, optical coherence tomography (OCT). METHODS A total of 120 cross-sections were evaluated by IB-IVUS and OCT at five cross-sections from 24 patients (24 lesions): at the minimal lumen area (MLA) and at 1 and 2mm proximal and distal to the MLA site in 24 lesions (9 treated with DES and 15 treated with BMS). IB-IVUS and OCT findings were analyzed according to the time at which restenosis was identified (early <12 months and late ≥12 months) and the stent type. RESULTS IB-IVUS was found to correctly characterize the neointima of both BMS and DES in-stent restenosis (ISR) as compared to OCT. The overall agreement between the pattern of ISR neointima by IB-IVUS and that by OCT was excellent (kappa=0.85, 95% CI 0.76-0.94). Late DES ISR was characterized by more non-homogeneous, low backscatter and lipid-laden neointima, as compared to the BMS equivalent (BMS vs. DES, 45.0% vs. 80.0%, p<0.01; 51.7% vs. 85.0%, p=0.008; 33.3% vs. 65.0%, p<0.01, respectively). CONCLUSIONS IB-IVUS assessment of the ISR neointima pattern appears to provide similar information as the gold-standard OCT in patients with stable angina. Both modalities suggested that late DES restenosis is characterized by a non-homogeneous lipid-laden neointima.

INSTANTANEOUS WAVE-FREE RATIO SCOUT PULLBACK (IFR SCOUT) PRE-ANGIOPLASTY PREDICTS HEMODYNAMIC OUTCOME IN HUMANS WITH CORONARY ARTERY DISEASE: PRIMARY RESULTS OF INTERNATIONAL MULTICENTRE IFR GRADIENT REGISTRY

Background: In tandem and diffuse disease, offline analysis of continuous instantaneous wave-free ratio (iFR) pullback measurement has been demonstrated to accurately predict the physiological outcome of revascularization. However, the accuracy of the real-time online analysis approach (iFR Scout)

TCT-9 A per-vessel level systematic review of computed tomography-derived FFR (FFR-CT) diagnostic accuracy studies: Implications for clinical decision-making

FFR-CT is a novel non-invasive method for the detection of ischemia. However, the diagnostic accuracy of FFR-CT over specific ranges of disease severity is not known, impacting the utility of FFR-CT for clinical decision-making. A systematic review was performed of studies comparing FFR-CT