Implications of coronary calcification on the assessment of plaque pathology: a comparison of computed tomography and multimodality intravascular imaging.

OBJECTIVES: This study aimed to investigate the impact of calcific (Ca) on the efficacy of coronary computed coronary angiography (CTA) in evaluating plaque burden (PB) and composition with near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) serving as the reference standard. MATERIALS AND METHODS: Sixty-four patients (186 vessels) were recruited and underwent CTA and 3-vessel NIRS-IVUS imaging (NCT03556644). Expert analysts matched and annotated NIRS-IVUS and CTA frames, identifying lumen and vessel wall borders. Tissue distribution was estimated using NIRS chemograms and the arc of Ca on IVUS, while in CTA Hounsfield unit cut-offs were utilized to establish plaque composition. Plaque distribution plots were compared at segment-, lesion-, and cross-sectional-levels. RESULTS: Segment- and lesion-level analysis showed no effect of Ca on the correlation of NIRS-IVUS and CTA estimations. However, at the cross-sectional level, Ca influenced the agreement between NIRS-IVUS and CTA for the lipid and Ca components (p-heterogeneity < 0.001). Proportional odds model analysis revealed that Ca had an impact on the per cent atheroma volume quantification on CTA compared to NIRS-IVUS at the segment level (p-interaction < 0.001). At lesion level, Ca affected differences between the modalities for maximum PB, remodelling index, and Ca burden (p-interaction < 0.001, 0.029, and 0.002, respectively). Cross-sectional-level modelling demonstrated Ca's effect on differences between modalities for all studied variables (p-interaction ≤ 0.002). CONCLUSION: Ca burden influences agreement between NIRS-IVUS and CTA at the cross-sectional level and causes discrepancies between the predictions for per cent atheroma volume at the segment level and maximum PB, remodelling index, and Ca burden at lesion-level analysis. CLINICAL RELEVANCE STATEMENT: Coronary calcification affects the quantification of lumen and plaque dimensions and the characterization of plaque composition coronary CTA. This should be considered in the analysis and interpretation of CTAs performed in patients with extensive Ca burden. KEY POINTS: Coronary CT Angiography is limited in assessing coronary plaques by resolution and blooming artefacts. Agreement between dual-source CT angiography and NIRS-IVUS is affected by a Ca burden for the per cent atheroma volume. Advanced CT imaging systems that eliminate blooming artefacts enable more accurate quantification of coronary artery disease and characterisation of plaque morphology.

Fractional flow reserve in clinical practice: from wire-based invasive measurement to image-based computation.

Fractional flow reserve (FFR) and instantaneous wave-free ratio are the present standard diagnostic methods for invasive assessment of the functional significance of epicardial coronary stenosis. Despite the overall trend towards more physiology-guided revascularization, there remains a gap between guideline recommendations and the clinical adoption of functional evaluation of stenosis severity. A number of image-based approaches have been proposed to compute FFR without the use of pressure wire and induced hyperaemia. In order to better understand these emerging technologies, we sought to highlight the principles, diagnostic performance, clinical applications, practical aspects, and current challenges of computational physiology in the catheterization laboratory. Computational FFR has the potential to expand and facilitate the use of physiology for diagnosis, procedural guidance, and evaluation of therapies, with anticipated impact on resource utilization and patient outcomes.

Diagnostic performance of angiography-derived fractional flow reserve: a systematic review and Bayesian meta-analysis.

Aims: Pressure-wire assessment of coronary stenosis is considered the invasive reference standard for detection of ischaemia-generating lesions. Recently, methods to estimate the fractional flow reserve (FFR) from conventional angiography without the use of a pressure wire have been developed, and were shown to have an excellent diagnostic accuracy. The present systematic review and meta-analysis aimed at determining the diagnostic performance of angiography-derived FFR for the diagnosis of haemodynamically significant coronary artery disease. Methods and results: A systematic review and meta-analysis of studies assessing the diagnostic performance of angiography-derived FFR systems were performed. The primary outcome of interest was pooled sensitivity and specificity. Thirteen studies comprising 1842 vessels were included in the final analysis. A Bayesian bivariate meta-analysis yielded a pooled sensitivity of 89% (95% credible interval 83-94%), specificity of 90% (95% credible interval 88-92%), positive likelihood ratio (+LR) of 9.3 (95% credible interval 7.3-11.7) and negative likelihood ratio (-LR) of 0.13 (95% credible interval 0.07-0.2). The summary area under the receiver-operating curve was 0.84 (95% credible interval 0.66-0.94). Meta-regression analysis did not find differences between the methods for pressure-drop calculation (computational fluid dynamics vs. mathematical formula), type of analysis (on-line vs. off-line) or software packages. Conclusion: The accuracy of angiography-derived FFR was good to detect haemodynamically significant lesions with pressure-wire measured FFR as a reference. Computational approaches and software packages did not influence the diagnostic accuracy of angiography-derived FFR. A diagnostic strategy trial with angiography-derived FFR evaluating clinical endpoints is warranted.

Invasive assessment of coronary artery disease.

Coronary artery disease is associated to high mortality and morbidity rates and an accurate diagnostic assessment during heart catheterization has a fundamental role in prognostic stratification and treatment choices. Coronary angiography has been integrated by intravascular imaging modalities, namely intravascular ultrasound and optical coherence tomography, which allow the precise quantification of the atherosclerotic burden of coronary arteries. The hemodynamic relevance of a given coronary stenosis can be assessed using stress or resting indexes: fractional flow reserve and instantaneous wave-free ratio are both coronary flow surrogates, used to guide percutaneous coronary interventions. This review summarizes the current state-of-the-art of invasive diagnostic methods during heart catheterization and highlights the potential role that an integration of anatomical and functional information enables.

Local Flow Patterns After Implantation of Bioresorbable Vascular Scaffold in Coronary Bifurcations　- Novel Findings by Computational Fluid Dynamics.

BACKGROUND: Development of methods for accurate reconstruction of bioresorbable scaffolds (BRS) and assessing local hemodynamics is crucial for investigation of vascular healing after BRS implantation.Methods and Results:Patients with BRS that crossed over in a coronary bifurcation were included for analysis. Reconstructions of the coronary lumen and BRS were performed by fusion of optical coherence tomography and coronary angiography generating a tree model (TM) and a hybrid model with BRS (TM-BRS). A virtual BRS model with thinner struts was created and all 3 models were analyzed using computational fluid dynamics to derive: (1) time-average shear stress (TASS), (2) TASS gradient (TASSG), which represents SS heterogeneity, and (3) fractional flow reserve (FFR). Reconstruction of the BRS was successful in all 10 patients. TASS and TASSG were both higher by TM-BRS than by TM in main vessels (difference 0.27±4.30 Pa and 10.18±27.28 Pa/mm, P<0.001), with a remarkable difference at side branch ostia (difference 13.51±17.40 Pa and 81.65±105.19 Pa/mm, P<0.001). With thinner struts, TASS was lower on the strut surface but higher at the inter-strut zones, whereas TASSG was lower in both regions (P<0.001 for all). Computational FFR was lower by TM-BRS than by TM for both main vessels and side branches (P<0.001). CONCLUSIONS: Neglecting BRS reconstruction leads to significantly lower SS and SS heterogeneity, which is most pronounced at side branch ostia. Thinner struts can marginally reduce SS heterogeneity.

Relationship Between Coronary Contrast-Flow Quantitative Flow Ratio and Myocardial Ischemia Assessed by SPECT MPI.

PURPOSE: A new method has been developed to calculate fractional flow reserve (FFR) from invasive coronary angiography, the so-called "contrast-flow quantitative flow ratio (cQFR)". Recently, cQFR was compared to invasive FFR in intermediate coronary lesions showing an overall diagnostic accuracy of 85%. The purpose of this study was to investigate the relationship between cQFR and myocardial ischemia assessed by single-photon emission computed tomography myocardial perfusion imaging (SPECT MPI). METHODS: Patients who underwent SPECT MPI and coronary angiography within 3 months were included. The cQFR computation was performed offline, using dedicated software. The cQFR computation was based on 3-dimensional quantitative coronary angiography (QCA) and computational fluid dynamics. The standard 17-segment model was used to determine the vascular territories. Myocardial ischemia was defined as a summed difference score ≥2 in a vascular territory. A cQFR of ≤0.80 was considered abnormal. RESULTS: Two hundred and twenty-four coronary arteries were analysed in 85 patients. Overall accuracy of cQFR to detect ischemia on SPECT MPI was 90%. In multivariable analysis, cQFR was independently associated with ischemia on SPECT MPI (OR per 0.01 decrease of cQFR: 1.10; 95% CI 1.04-1.18, p = 0.002), whereas clinical and QCA parameters were not. Furthermore, cQFR showed incremental value for the detection of ischemia compared to clinical and QCA parameters (global chi square 48.7 to 62.6; p <0.001). CONCLUSIONS: A good relationship between cQFR and SPECT MPI was found. cQFR was independently associated with ischemia on SPECT MPI and showed incremental value to detect ischemia compared to clinical and QCA parameters.

Anatomical and functional assessment of Tryton bifurcation stent before and after final kissing balloon dilatation: Evaluations by three-dimensional coronary angiography, optical coherence tomography imaging and fractional flow reserve.

OBJECTIVES: To assess the anatomical and functional impact of final kissing balloon inflation (FKBI) after implantation of a dedicated bifurcation stent system. BACKGROUND: Current evidence suggests clinical benefit of FKBI in patients undergoing bifurcation dilatation using the Tryton side branch stent (Tryton-SBS). We hypothesized that FKBI improves anatomical reconstruction and functional results of bifurcation treated by Tryton-SBS. METHODS: An unselected group of patients with complex bifurcation coronary lesions undergoing percutaneous coronary intervention (PCI) with Tryton-SBS underwent paired anatomical assessment with two- and three-dimensional quantitative coronary analysis (2D- and 3D-QCA), and optical coherence tomography (OCT), including 3D reconstruction before and after FKBI. Functional assessment by fractional flow reserve (FFR) was performed in the main branch (MB) and side branch (SB) before and after FKBI. RESULTS: Paired pre- and post-FKBI data were obtained in 10 patients. By OCT imaging, FKBI increased both the SB ostial area (4.93 ± 2.81 vs. 7.43 ± 2.87 mm2 , P < 0.001) and the SB maximum diameter (3.12 ± 0.98 vs. 3.82 ± 1.10 mm, P = 0.003). These findings were associated with a significant increase in FFR in the SB (0.90 ± 0.05 vs. 0.94 ± 0.03; P = 0.011), with no significant change in the MB (0.91 ± 0.05 vs. 0.92 ± 0.04; P = 0.470). CONCLUSIONS: In patients with complex bifurcation stenosis undergoing PCI with a dedicated bifurcation system, FKBI is associated with improved anatomical and functional results at the SB level, without compromising the result at the MB. © 2016 Wiley Periodicals, Inc.

An automated tool for cortical feature analysis: Application to differences on 7 Tesla T2* -weighted images between young and older healthy subjects.

PURPOSE: High field T2* -weighted MR images of the cerebral cortex are increasingly used to study tissue susceptibility changes related to aging or pathologies. This paper presents a novel automated method for the computation of quantitative cortical measures and group-wise comparison using 7 Tesla T2* -weighted magnitude and phase images. METHODS: The cerebral cortex was segmented using a combination of T2* -weighted magnitude and phase information and subsequently was parcellated based on an anatomical atlas. Local gray matter (GM)/white matter (WM) contrast and cortical profiles, which depict the magnitude or phase variation across the cortex, were computed from the magnitude and phase images in each parcellated region and further used for group-wise comparison. Differences in local GM/WM contrast were assessed using linear regression analysis. Regional cortical profiles were compared both globally and locally using permutation testing. The method was applied to compare a group of 10 young volunteers with a group of 15 older subjects. RESULTS: Using local GM/WM contrast, significant differences were revealed in at least 13 of 17 studied regions. Highly significant differences between cortical profiles were shown in all regions. CONCLUSION: The proposed method can be a useful tool for studying cortical changes in normal aging and potentially in neurodegenerative diseases. Magn Reson Med 74:240-248, 2015. © 2014 Wiley Periodicals, Inc.

Comparison of clinical interpretation with visual assessment and quantitative coronary angiography in patients undergoing percutaneous coronary intervention in contemporary practice: the Assessing Angiography (A2) project.

BACKGROUND: Studies conducted decades ago described substantial disagreement and errors in physicians' angiographic interpretation of coronary stenosis severity. Despite the potential implications of such findings, no large-scale efforts to measure or improve clinical interpretation were subsequently undertaken. METHODS AND RESULTS: We compared clinical interpretation of stenosis severity in coronary lesions with an independent assessment using quantitative coronary angiography (QCA) in 175 randomly selected patients undergoing elective percutaneous coronary intervention at 7 US hospitals in 2011. To assess agreement, we calculated mean difference in percent diameter stenosis between clinical interpretation and QCA and a Cohen weighted κ statistic. Of 216 treated lesions, median percent diameter stenosis was 80.0% (quartiles 1 and 3, 80.0% and 90.0%), with 213 (98.6%) assessed as ≥70%. Mean difference in percent diameter stenosis between clinical interpretation and QCA was 8.2±8.4%, reflecting an average higher percent diameter stenosis by clinical interpretation (P<0.001). A weighted κ of 0.27 (95% confidence interval, 0.18-0.36) was found between the 2 measurements. Of 213 lesions considered ≥70% by clinical interpretation, 56 (26.3%) were <70% by QCA, although none were <50%. Differences between the 2 measurements were largest for intermediate lesions by QCA (50% to <70%), with variation existing across sites. CONCLUSIONS: Physicians tended to assess coronary lesions treated with percutaneous coronary intervention as more severe than measurements by QCA. Almost all treated lesions were ≥70% by clinical interpretation, whereas approximately one quarter were <70% by QCA. These findings suggest opportunities to improve clinical interpretation of coronary angiography.

Texture analysis of ultrahigh field T2*-weighted MR images of the brain: application to Huntington's disease.

PURPOSE: To develop a framework for quantitative detection of between-group textural differences in ultrahigh field T2*-weighted MR images of the brain. MATERIALS AND METHODS: MR images were acquired using a three-dimensional (3D) T2*-weighted gradient echo sequence on a 7 Tesla MRI system. The phase images were high-pass filtered to remove phase wraps. Thirteen textural features were computed for both the magnitude and phase images of a region of interest based on 3D Gray-Level Co-occurrence Matrix, and subsequently evaluated to detect between-group differences using a Mann-Whitney U-test. We applied the framework to study textural differences in subcortical structures between premanifest Huntington's disease (HD), manifest HD patients, and controls. RESULTS: In premanifest HD, four phase-based features showed a difference in the caudate nucleus. In manifest HD, 7 magnitude-based features showed a difference in the pallidum, 6 phase-based features in the caudate nucleus, and 10 phase-based features in the putamen. After multiple comparison correction, significant differences were shown in the putamen in manifest HD by two phase-based features (both adjusted P values=0.04). CONCLUSION: This study provides the first evidence of textural heterogeneity of subcortical structures in HD. Texture analysis of ultrahigh field T2*-weighted MR images can be useful for noninvasive monitoring of neurodegenerative diseases.

Temporal evolution of strut light intensity after implantation of bioresorbable polymeric intracoronary scaffolds in the ABSORB cohort B trial-an application of a new quantitative method based on optical coherence tomography.

BACKGROUND: Quantitative light intensity analysis of the strut core by optical coherence tomography (OCT) may enable assessment of changes in the light reflectivity of the bioresorbable polymeric scaffold from polymer to provisional matrix and connective tissues, with full disappearance and integration of the scaffold into the vessel wall. The aim of this report was to describe the methodology and to apply it to serial human OCT images post procedure and at 6, 12, 24 and 36 months in the ABSORB cohort B trial. METHODS AND RESULTS: In serial frequency-domain OCT pullbacks, corresponding struts at different time points were identified by 3-dimensional foldout view. The peak and median values of light intensity were measured in the strut core by dedicated software. A total of 303 corresponding struts were serially analyzed at 3 time points. In the sequential analysis, peak light intensity increased gradually in the first 24 months after implantation and reached a plateau (relative difference with respect to baseline [%Dif]: 61.4% at 12 months, 115.0% at 24 months, 110.7% at 36 months), while the median intensity kept increasing at 36 months (%Dif: 14.3% at 12 months, 75.0% at 24 months, 93.1% at 36 months). CONCLUSIONS: Quantitative light intensity analysis by OCT was capable of detecting subtle changes in the bioresorbable strut appearance over time, and could be used to monitor the bioresorption and integration process of polylactide struts.

Hippocampal atrophy in people with memory deficits: results from the population-based IPREA study.

BACKGROUND: Clinical studies have shown that hippocampal atrophy is present before dementia in people with memory deficits and can predict dementia development. The question remains whether this association holds in the general population. This is of interest for the possible use of hippocampal atrophy to screen population for preventive interventions. The aim of this study was to assess hippocampal volume and shape abnormalities in elderly adults with memory deficits in a cross-sectional population-based study. METHODS: We included individuals participating in the Italian Project on the Epidemiology of Alzheimer Disease (IPREA) study: 75 cognitively normal individuals (HC), 31 individuals with memory deficits (MEM), and 31 individuals with memory deficits not otherwise specified (MEMnos). Hippocampal volumes and shape were extracted through manual tracing and the growing and adaptive meshes (GAMEs) shape-modeling algorithm. We investigated between-group differences in hippocampal volume and shape, and correlations with memory deficits. RESULTS: In MEM participants, hippocampal volumes were significantly smaller than in HC and were mildly associated with worse memory scores. Memory-associated shape changes mapped to the anterior hippocampus. Shape-based analysis detected no significant difference between MEM and HC, while MEMnos showed shape changes in the posterior hippocampus compared with HC and MEM groups. CONCLUSIONS: These findings support the discriminant validity of hippocampal volumetry as a biomarker of memory impairment in the general population. The detection of shape changes in MEMnos but not in MEM participants suggests that shape-based biomarkers might lack sensitivity to detect Alzheimer's-like pathology in the general population.

Association between echocardiography-derived haemodynamic force parameters and left ventricular reverse remodelling after cardiac resynchronization therapy.

AIMS: Cardiac resynchronization therapy (CRT) may induce left ventricular (LV) reverse remodelling (=LV response) in patients with heart failure. Intraventricular pressure gradients can be quantified using echocardiography-derived haemodynamic forces (HDF). The aim was to evaluate the association between baseline HDF and LV response and to compare the change of HDF after CRT between LV responders and LV non-responders. METHODS AND RESULTS: The following HDF parameters were assessed: 1)apical-basal (AB) strength, 2)lateral-septal strength, 3)force vector angle, 4)systolic AB impulse, 5)systolic force vector angle. LV response was defined as a reduction of LV end-systolic volume ≥15% at six months. One hundred ninety-six patients were included (64±11 years, 122(62%) men), 136(69%) showed LV response. On multivariable logistic regression analysis, the force vector angle in the complete heart cycle (OR 1.083 (95%CI 1.018, 1.153), p=0.012) and the systolic force vector angle (OR 1.089 (95%CI 1.021, 1.161), p=0.009), both included in separate models, were independently associated with LV response. Six months after CRT, LV responders had greater AB strength, AB impulse and higher force vector angles, while LV non-responders only showed improvement in the force vector angle in the complete heart cycle. CONCLUSION: The orientation of HDF at baseline is associated with LV response to CRT. Six months after CRT, the orientation of HDF improves in LV responders and LV non-responders, while the magnitude of AB HDF only improves in LV responders.

Correlation and Agreement of Quantitative Flow Ratio With Fractional Flow Reserve in Saphenous Vein Grafts.

BACKGROUND: The applicability of quantitative flow ratio (QFR), a nonhyperemic, invasive coronary angiography-derived computation of fractional flow reserve (FFR), has not been studied in coronary artery bypass grafts. We sought to explore the correlation and diagnostic agreement between QFR and FFR in saphenous vein grafts (SVGs). METHODS AND RESULTS: A total of 129 prospectively included patients (mean age 73±8 years, 84% male) with prior coronary artery bypass grafting underwent invasive coronary angiography and pressure-derived functional assessment in 150 nonoccluded SVGs. QFR dedicated angiography images of the SVGs were acquired and used for offline QFR computation. The diagnostic performance of QFR was compared with 2-dimensional quantitative coronary angiography, using FFR as a reference. A threshold of ≤0.80 was used to define functional significance. QFR was successfully computed in 140 (93%) SVGs. We found a significant correlation between QFR and FFR (r=0.72, P<0.001). FFR indicated significant disease in 43 (31%) SVGs, whereas QFR analysis showed significant lesions in 53 (38%) bypass grafts. QFR exhibited a higher sensitivity and diagnostic accuracy compared with angiographic lesion assessment (84% versus 63%, P=0.030 and 83% versus 74%, P=0.036, respectively), whereas specificity did not differ (82% versus 79%, P=0.466). Lastly, QFR demonstrated a higher area under the receiver operating curve than quantitative coronary angiography (0.90 versus 0.82, P=0.008) for the detection of FFR-defined significant vein graft disease. CONCLUSIONS: This study shows the potential applicability of contemporary QFR computation in venous bypass grafts with a moderate correlation and good diagnostic accuracy compared with functional assessment using FFR.

Efficacy of Coronary Calcium Score in Predicting Coronary Artery Morphology in Patients With Obstructive Coronary Artery Disease.

Background: Coronary artery calcium score (CACS) is an established marker of coronary artery disease (CAD) and has been extensively used to stratify risk in asymptomatic individuals. However, the value of CACS in predicting plaque morphology in patients with advanced CAD is less established. The present analysis aims to assess the association between CACS and plaque characteristics detected by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS) imaging in patients with obstructive CAD. Methods: Seventy patients with obstructive CAD underwent coronary computed tomography angiography (CTA) and 3-vessel NIRS-IVUS imaging were included in the present analysis. The CTA data were used to measure the CACS in the entire coronary tree and the segments assessed by NIRS-IVUS, and these estimations were associated with the NIRS-IVUS measurements at a patient and segment level. Results: In total, 65 patients (188 segments) completed the study protocol and were included in the analysis. A weak correlation was noted between the CACS, percent atheroma volume (r = 0.271, P = .002), and the calcific burden measured by NIRS-IVUS (r = 0.648, P < .001) at patient-level analysis. Conversely, there was no association between the CACS and the lipid content, or the incidence of high-risk plaques detected by NIRS. Linear regression analysis at the segment level demonstrated an association between the CACS and the total atheroma volume (coefficient, 0.087; 95% CI, 0.024-0.149; P = .008) and the calcific burden (coefficient, 0.117; 95% CI, 0.048-0.186; P = .001), but there was no association between the lipid content or the incidence of high-risk lesions. Conclusions: In patients with obstructive CAD, the CACS is not associated with the lipid content or plaque phenotypes. These findings indicate that the CACS may have a limited value for screening or stratifying cardiovascular risk in symptomatic patients with a high probability of CAD.

Efficacy of human experts and an automated segmentation algorithm in quantifying disease pathology in coronary computed tomography angiography: A head-to-head comparison with intravascular ultrasound imaging.

BACKGROUND: Coronary computed tomography angiography (CCTA) analysis is currently performed by experts and is a laborious process. Fully automated edge-detection methods have been developed to expedite CCTA segmentation however their use is limited as there are concerns about their accuracy. This study aims to compare the performance of an automated CCTA analysis software and the experts using near-infrared spectroscopy-intravascular ultrasound imaging (NIRS-IVUS) as a reference standard. METHODS: Fifty-one participants (150 vessels) with chronic coronary syndrome who underwent CCTA and 3-vessel NIRS-IVUS were included. CCTA analysis was performed by an expert and an automated edge detection method and their estimations were compared to NIRS-IVUS at a segment-, lesion-, and frame-level. RESULTS: Segment-level analysis demonstrated a similar performance of the two CCTA analyses (conventional and automatic) with large biases and limits of agreement compared to NIRS-IVUS estimations for the total atheroma (ICC: 0.55 vs 0.25, mean difference:192 (-102-487) vs 243 (-132-617) and percent atheroma volume (ICC: 0.30 vs 0.12, mean difference: 12.8 (-5.91-31.6) vs 20.0 (0.79-39.2). Lesion-level analysis showed that the experts were able to detect more accurately lesions than the automated method (68.2 â€‹% and 60.7 â€‹%) however both analyses had poor reliability in assessing the minimal lumen area (ICC 0.44 vs 0.36) and the maximum plaque burden (ICC 0.33 vs 0.33) when NIRS-IVUS was used as the reference standard. CONCLUSIONS: Conventional and automated CCTA analyses had similar performance in assessing coronary artery pathology using NIRS-IVUS as a reference standard. Therefore, automated segmentation can be used to expedite CCTA analysis and enhance its applications in clinical practice.

Quantitative flow ratio versus fractional flow reserve for Heart Team decision-making in multivessel disease: the randomised, multicentre DECISION QFR trial.

BACKGROUND: Vessel-level physiological data derived from pressure wire measurements are one of the important determinant factors in the optimal revascularisation strategy for patients with multivessel disease (MVD). However, these may result in complications and a prolonged procedure time. AIMS: The feasibility of using the quantitative flow ratio (QFR), an angiography-derived fractional flow reserve (FFR), in Heart Team discussions to determine the optimal revascularisation strategy for patients with MVD was investigated. METHODS: Two Heart Teams were randomly assigned either QFR- or FFR-based data of the included patients. They then discussed the optimal revascularisation mode (percutaneous coronary intervention [PCI] or coronary artery bypass grafting [CABG]) for each patient and made treatment recommendations. The primary endpoint of the trial was the level of agreement between the treatment recommendations of both teams as assessed using Cohen's kappa. RESULTS: The trial included 248 patients with MVD from 10 study sites. Cohen's kappa in the recommended revascularisation modes between the QFR and FFR approaches was 0.73 [95% confidence interval {CI} : 0.62-0.83]. As for the revascularisation planning, agreements in the target vessels for PCI and CABG were substantial for both revascularisation modes (Cohen's kappa=0.72 [95% CI: 0.66-0.78] and 0.72 [95% CI: 0.66-0.78], respectively). The team assigned to the QFR approach provided consistent recommended revascularisation modes even after being made aware of the FFR data (Cohen's kappa=0.95 [95% CI:0.90-1.00]). CONCLUSIONS: QFR provided feasible physiological data in Heart Team discussions to determine the optimal revascularisation strategy for MVD. The QFR and FFR approaches agreed substantially in terms of treatment recommendations.

Quantitative angiography and optical coherence tomography for the functional assessment of nonobstructive coronary stenoses: comparison with fractional flow reserve.

BACKGROUND: The purpose was to compare 3-dimensional quantitative coronary angiography (3D-QCA) with optical coherence tomography (OCT) for the functional assessment of nonobstructive coronary stenoses, as evaluated by fractional flow reserve (FFR). METHODS: Fifty-five nonobstructive coronary stenoses (30%-50% diameter stenosis by visual estimation) were assessed in 36 patients using FFR, 2-dimensional QCA (2D-QCA), 3D-QCA, and OCT. RESULTS: Angiographic stenosis severity by 2D-QCA was 34% ± 13% diameter stenosis, and minimal lumen diameter (MLD) was 1.77 ± 0.58 mm. Fractional flow reserve values were 0.85 ± 0.10. Correlation coefficients between FFR and MLD or minimal lumen area (MLA) were highly significant for both 2D- and 3D-QCA (all P < .001), but higher R(2) values were observed for 3D-QCA measurements. Although significant, correlation coefficients between OCT and FFR data were weak (R(2) = 0.28, P = .001 for MLD and R(2) = 0.23, P = .003 for MLA). Correlation coefficients with FFR were significantly higher for 3D-QCA than for OCT (P values for MLD and MLA = .043 and .042, respectively). Nonobstructive stenoses with MLD >1.53 mm or MLA >2.43 mm(2) are unlikely to be hemodynamically significant. CONCLUSIONS: In nonobstructive coronary stenoses, anatomical parameters derived from 3D-QCA can best identify lesions with preserved FFR values.

Automated quantitative coronary computed tomography correlates of myocardial ischaemia on gated myocardial perfusion SPECT.

PURPOSE: Automated software tools have permitted more comprehensive, robust and reproducible quantification of coronary stenosis, plaque burden and plaque location of coronary computed tomography angiography (CTA) data. The association between these quantitative CTA (QCT) parameters and the presence of myocardial ischaemia has not been explored. The aim of the present investigation was to evaluate the association between QCT parameters of coronary artery lesions and the presence of myocardial ischaemia on gated myocardial perfusion single-photon emission CT (SPECT). METHODS: Included in the study were 40 patients (mean age 58.2 ± 10.9 years, 27 men) with known or suspected coronary artery disease (CAD) who had undergone multidetector row CTA and gated myocardial perfusion SPECT within 6 months. From the CTA datasets, vessel-based and lesion-based visual analyses were performed. Consecutively, lesion-based QCT was performed to assess plaque length, plaque burden, percentage lumen area stenosis and remodelling index. Subsequently, the presence of myocardial ischaemia was assessed using the summed difference score (SDS ≥2) on gated myocardial perfusion SPECT. RESULTS: Myocardial ischaemia was seen in 25 patients (62.5%) in 37 vascular territories. Quantitatively assessed significant stenosis and quantitatively assessed lesion length were independently associated with myocardial ischaemia (OR 7.72, 95% CI 2.41-24.7, p < 0.001, and OR 1.07, 95% CI 1.00-1.45, p = 0.032, respectively) after correcting for clinical variables and visually assessed significant stenosis. The addition of quantitatively assessed significant stenosis (χ(2) = 20.7) and lesion length (χ(2) = 26.0) to the clinical variables and the visual assessment (χ(2) = 5.9) had incremental value in the association with myocardial ischaemia. CONCLUSION: Coronary lesion length and quantitatively assessed significant stenosis were independently associated with myocardial ischaemia. Both quantitative parameters have incremental value over baseline variables and visually assessed significant stenosis. Potentially, QCT can refine assessment of CAD, which may be of potential use for identification of patients with myocardial ischaemia.

Clinical validation of the new T- and Y-shape models for the quantitative analysis of coronary bifurcations: an interobserver variability study.

OBJECTIVES: This article presents the results of an interobserver validation study of our new T- and Y-shape bifurcation models including their edge segment analyses. BACKGROUND: Over the last years, the coronary artery intervention procedures have been developed more and more toward bifurcation stenting. Because traditional straight vessel quantitative coronary arteriography (QCA) is not sufficient for these measurements, the need has grown for new bifurcation analysis methods. METHODS: In this article, our two new bifurcation analysis models are presented, the Y-shape and T-shape model. These models were designed for the accurate measurement of the clinically relevant parameters of a coronary bifurcation, for different morphologies and intervention strategies and include an edge segment analysis, to accurately measure (drug-eluting) stent, stent edge, and ostial segment parameters. RESULTS: The results of an interobserver validation study of our T-shape and Y-shape analyses are presented, both containing the pre- and post-intervention analyses of each 10 cases. These results are associated with only small systematic and random errors, in the majority of the cases compliant with the QCA guidelines for straight analyses. The results for the edge segment analyses are also very good, with almost all the values within the margins that have been set by our brachytherapy directive. CONCLUSIONS: Our new bifurcation approaches including their edge segment analyses are very robust and reproducible, and therefore a great extension to the field of quantitative coronary angiography.