OBJECTIVES This study sought to investigate the performance of various cardiac computed tomography (CT)-derived atherosclerotic plaque metrics for predicting provocable myocardial ischemia... Show moreOBJECTIVES This study sought to investigate the performance of various cardiac computed tomography (CT)-derived atherosclerotic plaque metrics for predicting provocable myocardial ischemia.BACKGROUND The association of coronary arterial diameter stenosis with myocardial ischemia is only modest, but cardiac CT provides several other, readily available atherosclerosis metrics, which may have incremental value.METHODS The study analyzed 873 nonstented coronary arteries and their myocardial perfusion territories in 356 patients (mean 62 years of age) enrolled in the CORE320 (Coronary Artery Evaluation using 320-row Multidetector Computed Tomography Angiography and Myocardial Perfusion) study. Myocardial perfusion defects in static CT perfusion imaging were graded at rest and after adenosine in 13 myocardial segments using a 4-point scale. The summed difference score was calculated by subtracting the summed rest score from the summed stress score. Reversible ischemia was defined as summed difference score >= 1. In a sensitivity analysis, results were also provided using single-photon emission computed tomography (SPECT) as the reference standard. Vessel based predictor variables included maximum percent diameter stenosis, lesion length, coronary calcium score, maximum cross-sectional calcium arc, percent atheroma volume (PAV), low-attenuation atheroma volume, positive (external) vascular remodeling, and subjective impression of "vulnerable plaque." The study used logistic regression models to assess the association of plaque metrics with myocardial ischemia.RESULTS In univariate analysis, all plaque metrics were associated with reversible ischemia. In the adjusted logistic model, only maximum percent diameter stenosis (1.26; 95% confidence interval: 1.15 to 1.38) remained an independent predictor. With SPECT as outcome variable, PAV and "vulnerable" plaque remained predictive after adjustment. In vessels with intermediate stenosis (40% to 70%), no single metric had clinically meaningful incremental value.CONCLUSIONS Various plaque metrics obtained by cardiac CT predict provocable myocardial ischemia by CT perfusion imaging through their association with maximum percent stenosis, while none had significant incremental value. With SPECT as reference standard, PAV and "vulnerable plaque" remained predictors of ischemia after adjustment but the predictive value added to stenosis assessment alone was small. (C) 2019 by the American College of Cardiology Foundation. Show less
Quantitative flow ratio (QFR) is a novel technique to calculate fractional flow reserve (FFR), without hyperemia induction or a pressure wire, and has not yet been validated in patients with... Show moreQuantitative flow ratio (QFR) is a novel technique to calculate fractional flow reserve (FFR), without hyperemia induction or a pressure wire, and has not yet been validated in patients with diabetes mellitus (DM), who are at increased risk of coronary microvascular dysfunction. The purpose of our study was to compare the diagnostic performance of QFR in diabetic and nondiabetic patients. Patients who underwent invasive coronary angiography and subsequent invasive FFR measurement within 6 months were included. QFR was determined in all coronary arteries in which invasive FFR was performed, using a dedicated software package. Diagnostic accuracy and the area under the receiver-operating characteristic curve (AUC) were determined for QFR, using an invasive FFR cut-off value of <= 0.80 as the reference standard. In total, 320 coronary arteries from 66 (25%) diabetic and 193 (75%) nondiabetic patients were analyzed. On a vessel-based analysis, diagnostic accuracy, sensitivity, and specificity showed no significant difference between diabetic and nondiabetic patients: 88% versus 85% (p = 0.47), 71% versus 69% (p = 0.72), and 95% versus 91% (p = 0.24). Moreover, the AUC was not significantly different between patients with and without DM, 0.91 versus 0.93 (p = 0.74). The per-vessel AUC was significantly higher for QFR compared with percent diameter stenosis in both diabetic and nondiabetic patients, 0.91 versus 0.76 (p < 0.05) and 0.93 versus 0.77 (p < 0.001), respectively. In conclusion, we showed a good diagnostic performance of QFR which was independent of the presence of DM. (C) 2019 The Authors. Published by Elsevier Inc. Show less
A dedicated software package that could semi-automatically assess differences in aortic maximal cross-sectional diameters from consecutive CT scans would most likely reduce the post-processing time... Show moreA dedicated software package that could semi-automatically assess differences in aortic maximal cross-sectional diameters from consecutive CT scans would most likely reduce the post-processing time and effort by the physicians. The aim of this study was to present and assess the quality of a new tool for the semi-automatic quantification of thoracic aorta dilation dimensions. Twenty-nine patients with two CTA scans of the thoracic aorta for which the official clinical report indicated an increase in aortic diameters were included in the study. Aortic maximal cross-sectional diameters of baseline and follow-up studies generated semi-automatically by the software were compared with corresponding manual measurements. The semi-automatic measurements were performed at seven landmarks defined on the baseline scan by two operators. Bias, Bland-Altman plots and intraclass correlation coefficients were calculated between the two methods and, for the semi-automatic software, also between two observers. The average time difference between the two scans of a single patient was 1188 +/- 622 days. For the semi-automatic software, in 2 out of 29 patients, manual interaction was necessary; in the remaining 27 patients (93.1%), semi-automatic results were generated, demonstrating excellent intraclass correlation coefficients (all values0.91) and small differences, especially for the proximal aortic arch (baseline: 0.19 +/- 1.30mm; follow-up: 0.44 +/- 2.21mm), the mid descending aorta (0.37 +/- 1.64mm; 0.37 +/- 2.06mm), and the diaphragm (0.30 +/- 1.14mm; 0.37 +/- 1.80mm). The inter-observer variability was low with all errors in diameters1mm, and intraclass correlation coefficients all 0.95. The semi-automatic tool decreased the processing time by 40% (13 vs. 22min). In this work, a semi-automatic software package that allows the assessment of thoracic aorta diameters from baseline and follow-up CTs (and their differences), was presented, and demonstrated high accuracy and low inter-observer variability. Show less
Optical coherence tomography based computational flow dynamic (CFD) modeling provides detailed information about the local flow behavior in stented/scaffolded vessel segments. Our aim is to... Show moreOptical coherence tomography based computational flow dynamic (CFD) modeling provides detailed information about the local flow behavior in stented/scaffolded vessel segments. Our aim is to investigate the in-vivo effect of strut thickness and strut protrusion on endothelial wall shear stress (ESS) distribution in ArterioSorb Absorbable Drug-Eluting Scaffold (ArterioSorb) and Absorb everolimus-eluting Bioresorbable Vascular Scaffold (Absorb) devices that struts with similar morphology (quadratic structure) but different thickness. In three animals, six coronary arteries were treated with ArterioSorb. At different six animals, six coronary arteries were treated with Absorb. Following three-dimensional(3D) reconstruction of the coronary arteries, Newtonian steady flow simulation was performed and the ESS were estimated. Mixed effects models were used to compare ESS distribution in the two devices. There were 4591 struts in the analyzed 477 cross-sections in Absorb (strut thickness=157 mu m) and 3105 struts in 429 cross-sections in ArterioSorb (strut thickness=95 mu m) for the protrusion analysis. In cross-section level analysis, there was significant difference between the scaffolds in the protrusion distances. The protrusion was higher in Absorb (97% of the strut thickness) than in ArterioSorb (88% of the strut thickness). ESS was significantly higher in ArterioSorb (1.52 +/- 0.34Pa) than in Absorb (0.73 +/- 2.19Pa) (p=0.001). Low- and very-low ESS data were seen more often in Absorb than in ArterioSorb. ArterioSorb is associated with a more favorable ESS distribution compared to the Absorb. These differences should be attributed to different strut thickness/strut protrusion that has significant effect on shear stress distribution. Show less
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 ... Show moreOBJECTIVES 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 (fSS(QFR)) on clinical outcomes.BACKGROUND The applicability of QFR in patients with 3-vessel disease and the feasibility of fSS(QFR) 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 fSS(QFR) 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, fSS(QFR) 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 fSS(QFR) 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 fSS(QFR) has the potential to further refine prognostic risk estimation compared with the classic anatomic SYNTAX score. (c) 2019 by the American College of Cardiology Foundation. Show less
Chen, H.; Li, Y.G.; Reiber, J.H.C.; Lange, J. de; Tu, S.X.; Stelt, P. van der; ... ; Aarab, G. 2018
