Non-invasive CT Angiography Research Articles

Coronary plaque volume burden and composition in patients with non-hemodynamically significant coronary artery plaques and systemic inflammation

Abstract Introduction Atherosclerotic coronary disease is a leading cause of morbidity and mortality worldwide. Systemic inflammation can affect plaque composition and thus increase cardiovascular risk. Identifying plaque characteristics in these patients could be useful to learn how inflammation (identified by easy to access parameters, like high ferritin and CRP) affects plaque composition in these challenging patients. Purpose We aimed to evaluate the association of systemic inflammation identified by high ferritin and/or high C-reactive protein (CRP) with coronary plaque volume and composition in patients with non-hemodynamically significant coronary artery plaques (stenosis <50%). Methods We prospectively recruited 109 patients referred for noninvasive CT angiography (from November 2023 to January 2024) with suspected coronary artery disease. 20 had totally/partially non-calcified, non-significant coronary plaques (stenosis <50%). Plaque volume was measured. Plaque components were stablished as calcified (>200 UH), lipidic (<60 UH) and fibrous (60-200 UH). Systemic inflammation was identified when ferritin was >300 ng/mL and/or C-reactive protein CRP was >5 mg/L, according to our laboratory high normal limits. CT scan images were acquired with a 128 detectors dual-layer CT scan with prospective-retrospective/synchronization. Intravascular iodine-based contrast agent was administered. Results Mean age was 60 ± 11 years old and 75% of patients were men. 55% had high blood pressure, 65% were current or previous smokers and 40% had dyslipidemia (35% received statins). 10% were diabetic. There were no difference between groups for these characteristics. We analyzed 33 plaques. Fibrous plaque volume was found to be significantly higher in patients with high ferritin (66.9 vs 32.5 mm3; p = 0.04) and in patients with high CRP (78.7 vs 36.4 mm3; p = 0.05). The percentage of fibrous plaque tended to be higher in patients with higher ferritin and CRP (54.9 vs 38.9; p = 0.06 and 60.6 vs 40.7%; p = 0.07, respectively). Conclusions Systemic inflammation affecting coronary plaque composition in non-hemodynamically significant coronary atherosclerotic disease can by identified by high ferritin and high CRP levels. It is associated with higher fibrous plaque volumes. This finding suggest that systemic inflammation can associate more vulnerable plaques and might benefit from more aggressive management of non-hemodynamically significant atherosclerosis.TableFigure

Post-catheterization Common Femoral Artery Pseudoaneurysm in a Patient with a Mechanical Mitral Valve Requiring Anticoagulation: A Case Report

Iatrogenic femoral pseudoaneurysms are a rare complication of transfemoral vascular access. We present a case of a 65-year-old woman with a mechanical mitral valve requiring warfarin, who developed a femoral pseudoaneurysm four days after cardiac catheterization with femoral access. The patient developed a 17 x 10 x 17 cm rectus sheath hematoma and was treated with ultrasound-guided thrombin injection. Anticoagulation was held for three days while the patient was monitored for further bleeding and later restarted based on shared decision-making, given the risk of valve thrombosis. There are few guidelines regarding the re-initiation of anticoagulation in high-risk bleeding patients with mechanical mitral valves. Non-invasive coronary computed tomography angiography should be considered in patients on anticoagulation who require non-emergent cardiac ischemic evaluation.

Computational fluid dynamics modeling of coronary artery blood flow using OpenFOAM: Validation with the food and drug administration benchmark nozzle model.

Cardiovascular disease (CVD), a global health concern, particularly coronary artery disease (CAD), poses a significant threat to well-being. Seeking safer and cost-effective diagnostic alternatives to invasive coronary angiography, noninvasive coronary computed tomography angiography (CCTA) gains prominence. This study employed OpenFOAM, an open-source Computational Fluid Dynamics (CFD) software, to analyze hemodynamic parameters in coronary arteries with serial stenoses. Patient-specific three-dimensional (3D) models from CCTA images offer insights into hemodynamic changes. OpenFOAM breaks away from traditional commercial software, validated against the FDA benchmark nozzle model for reliability. Applying this refined methodology to seventeen coronary arteries across nine patients, the study evaluates parameters like fractional flow reserve computed tomography simulation (FFRCTS), fluid velocity, and wall shear stress (WSS) over time. Findings include FFRCTS values exceeding 0.8 for grade 0 stenosis and falling below 0.5 for grade 5 stenosis. Central velocity remains nearly constant for grade 1 stenosis but increases 3.4-fold for grade 5 stenosis. This research innovates by utilizing OpenFOAM, departing from previous reliance on commercial software. Combining qualitative stenosis grading with quantitative FFRCTS and velocity measurements offers a more comprehensive assessment of coronary artery conditions. The study introduces 3D renderings of wall shear stress distribution across stenosis grades, providing an intuitive visualization of hemodynamic changes for valuable insights into coronary stenosis diagnosis.

Ensembled-SAMs for Enhanced Small Coronary Artery Segmentation in CCTA Images.

Accurate coronary artery segmentation is crucial for quantitative analysis of coronary arteries in noninvasive coronary computed tomography angiography (CCTA) images. However, current segmentation algorithms often have unsatisfactory recall due to the small size and complex morphology of coronary arteries, particularly in the distal segments. To address this issue, we introduce a new fully automated method named Ensembled-SAMs, which harnesses the strengths of the Segment Anything Model (SAM) and the no-new-U-Net (nnU-Net). First, noisy bounding box prompts are automatically generated by a vesselness algorithm that highlights the tubular structures in the CCTA images. These noisy prompts are then used to fine-tune the SAM and its two variants separately. The SAM variants introduce a classification head in their mask decoder to alleviate the false positives. In addition, an nnU-Net segmentation network is trained from scratch. Finally, the outputs of the SAMs and the nnU-Net are strategically aggregated to obtain the final segmentation result. Experiments on both a self-built dataset and the public Automated Segmentation of Coronary Arteries (ASOCA) challenge dataset demonstrate that the proposed Ensembled-SAMs outperforms the state-of-the-arts, achieving precise segmentation of coronary arteries, with particular enhancement in delineating small coronary artery segments.

RAPID aneurysm accurately measures aneurysm size on CT angiography compared to three-dimensional digital subtraction angiography.

Cerebral aneurysms are often identified and characterized on non-invasive CT Angiography (CTA) images, but digital subtraction angiography (DSA) is the gold standard for aneurysm evaluation. We compared cerebral aneurysm size measurements as measured from CTA processed by a semi-automated artificial intelligence software program (RAPID Aneurysm) and three-dimensional rotational DSA (3D-DSA). We performed a retrospective cohort study of consecutive patients with a cerebral aneurysm who underwent CTA and DSA with 3D reformations. CTA images were processed by RAPID Aneurysm to determine aneurysm height, width, and neck width. The reference standard was aneurysm measurements on 3D-DSA as measured by two neurointerventionalists. Both readers were blinded to RAPID Aneurysm measurements. Correlation and bias between these measurements were determined. Results from 50 patients with 50 aneurysms were compared. 32 patients (64%) were female. Median age was 65 (IQR: 56.25-71.75). 37 patients (74%) presented with ruptured aneurysms. The aneurysms represented a range of aneurysm sizes (1.9-33.3 mm; IQR 3.6-7.2 mm). RAPID Aneurysm size measurements showed excellent correlation and low bias (correlation, mean difference) when compared to the reference standard for aneurysm height (0.98, -0.9 mm), width (0.98, 0.1 mm), and neck width (0.94, 1.1 mm). The inter-reader comparison between the two neurointerventionalists was similarly excellent for aneurysm height (0.97, -0.4 mm), width (0.98, -0.2 mm), and neck width (0.89, 0.8 mm). RAPID Aneurysm measurement of cerebral aneurysm height, width, and neck width on CTA is strongly correlated to expert neurointerventionalist measurements on 3D-DSA.

Impact of Intensive Low-Density Lipoprotein Cholesterol-Lowering Therapy on Coronary Artery Plaques in Acute Coronary Syndrome

Acute coronary syndrome (ACS) is associated with a high incidence of unstable plaques beyond the culprit lesion, leading to early recurrence of cardiovascular events. Coronary computed tomography angiography (CCTA) can be used to noninvasively observe plaques throughout the coronary arteries. To evaluate the impact of intensive low-density lipoprotein cholesterol (LDL-C)-lowering therapy on quantitative changes in coronary plaque, assessed using CCTA in a study population with ACS. In total, 81 consecutive patients with ACS who underwent CCTA at discharge and at 1-year follow-up from April 2018 to March 2020 were analyzed. The patients were divided into 2 groups: those who achieved LDL-C <70 mg/100 ml and those who did not. Changes in plaque morphology within and between the 2 groups were compared using CCTA. A total of 198 vessels were analyzed. The calcified plaque volume was significantly increased in the LDL-C <70 group (65.8 ± 80.1 mm3 to 73.6 ± 83.7 mm3, p=0.007), whereas no significant change was observed in the LDL-C ≥70 group (106.9 ± 161.7 mm3 to 105.7 ± 137.5 mm3, p=0.552). Percent change in low-attenuation plaque volume in the LDL <70 group was significantly lower than in the LDL-C ≥70 group (17.2 ± 90.9% vs 84.4 ± 162.6%, p=0.020). Receiver operating characteristic curve analysis demonstrated that the target LDL-C level for low-attenuation plaque volume regression was 64 mg/100 ml. In conclusion, noninvasive CCTA demonstrated that intensive LDL-C lowering in high-risk patients with ACS could potentially lead to plaque stabilization.

Abstract 12259: Recurrent Coronary Artery Dissection in Patient With Systemic Medium-Sized Vessel Vasculitis

Introduction: Universal definition of myocardial infarction (MI) categorizes spontaneous coronary artery dissection (SCAD) as Type 2 ischemia from non-atherothrombotic obstruction. SCAD is rare but growing evidence suggests it is more common than previously understood. Overlap in clinical presentation with Type 1 MI makes invasive coronary angiography (ICA) the gold standard for diagnosis. Here we present a patient with polyarteritis nodosa (PAN) and the sequelae of coronary artery aneurysms and dissections visualized by ICA and further characterized by noninvasive coronary computed tomography angiography (CCTA). Case Report: A 37-year-old man with smoking and hypertension history presented with acute chest pain that felt similar to when he was diagnosed with SCAD of the first diagonal branch one year prior by ICA. Workup then included elevated inflammatory markers and further imaging demonstrating ectatic and beaded-appearing major intra-abdominal and vertebral arteries consistent with PAN. He completed outpatient cyclophosphamide and continued on chronic oral steroids.The catheterization lab was activated on this presentation for ST segment elevations on initial ECG concerning for an inferior MI. Here the distal branches of the right coronary artery (RCA) had new aneurysms and long stenoses with severe luminal narrowing and intramural hematoma consistent with Type 2 SCAD. The culprit lesions had normal TIMI grade 3 flow so were not revascularized. CCTA further characterized the filling defect and RCA false lumen as Type 1 SCAD. Echocardiogram demonstrated a new wall motion dysfunction in correlative distribution. He was optimized on medical therapy including continued dual antiplatelet agents and steroids. Discussion: This patient’s case lends itself to the hypothesis that his PAN manifested ectatic changes to the coronary vasculature from inflammation that predisposed him to recurrent dissection. Therefore, it is reasonable to initiate a vasculitis workup following discovery of coronary artery ectasia and/or dissection. CCTA may even be an effective tool for diagnosis and surveillance of such disease in the right patient and as a means to avoid invasive testing risks.

Computed Tomography-Based Angiographic Evaluation of Graft Patency Rate After Coronary Artery Bypass Graft Surgery in Bangladesh.

BackgroundThis study aims to assess the graft patency rate following coronary artery bypass graft (CABG) surgery using noninvasive CT angiography. Materials and methodsA total of 68 patients were retrospectively evaluated with CT angiography (group I: 34 patients with coronary endarterectomy (CE) and group II: 34 patients without CE). CE was performed in multi-segmental diffuse coronary artery disease (CAD) or when calcified or extremely thick plaques made anastomosis troublesome. A team of two experts, an interventional radiologist and a cardiac surgeon, did the evaluations of graft patency rate.ResultsA total of 205 bypass grafts were evaluated in 68 post-CABG status patients (110 grafts in group I and 95 grafts in group II; moreover, 82 were arterial and 123 were venous grafts). Post CABG, CT angiography demonstrated a graft patency rate of about 90% in both study groups at five years follow up, which was statistically insignificant (P > 0.05) in terms of graft patency rate. Following CE, five-year angina-free survival rates were 89% and 91% in groups I and II, respectively.ConclusionCABG surgery with endarterectomy is reliable and effective. It achieves the desired surgical myocardial revascularization in patients with diffuse calcified CAD having no alternative options for adequate myocardial revascularization.

Detailed behaviour of endothelial wall shear stress across coronary lesions from non-invasive imaging with coronary computed tomography angiography.

Evolving evidence suggests that endothelial wall shear stress (ESS) plays a crucial role in the rupture and progression of coronary plaques by triggering biological signalling pathways. We aimed to investigate the patterns of ESS across coronary lesions from non-invasive imaging with coronary computed tomography angiography (CCTA), and to define plaque-associated ESS values in patients with coronary artery disease (CAD). Symptomatic patients with CAD who underwent a clinically indicated CCTA scan were identified. Separate core laboratories performed blinded analysis of CCTA for anatomical and ESS features of coronary atherosclerosis. ESS was assessed using dedicated software, providing minimal and maximal ESS values for each 3 mm segment. Each coronary lesion was divided into upstream, start, minimal luminal area (MLA), end and downstream segments. Also, ESS ratios were calculated using the upstream segment as a reference. From 122 patients (mean age 64 ± 7 years, 57% men), a total of 237 lesions were analyzed. Minimal and maximal ESS values varied across the lesions with the highest values at the MLA segment [minimal ESS 3.97 Pa (IQR 1.93-8.92 Pa) and maximal ESS 5.64 Pa (IQR 3.13-11.21 Pa), respectively]. Furthermore, minimal and maximal ESS values were positively associated with stenosis severity (P < 0.001), percent atheroma volume (P < 0.001), and lesion length (P ≤ 0.023) at the MLA segment. Using ESS ratios, similar associations were observed for stenosis severity and lesion length. Detailed behaviour of ESS across coronary lesions can be derived from routine non-invasive CCTA imaging. This may further improve risk stratification.

Abstract 13620: Comparison of Endothelial Shear Stress (ESS) Computation Utilizing Non-Invasive Coronary Computed Tomography Angiography (CCTA) vs Invasive Intravascular Ultrasound (IVUS) Imaging

Introduction: Risk-stratification of individual coronary plaques is an important goal to detect high-risk plaques likely to progress/destabilize, which could inform preemptive intervention to prevent adverse cardiac events. IVUS imaging, the current gold standard to assess plaque risk, has shown that biomechanical variables, particularly local ESS, contributes critical synergistic prognostic insight when combined with anatomic high-risk plaque features. Non-invasive risk assessment of coronary plaques with CCTA would be invaluable to enable broad population risk screening, but it is unknown whether CCTA, which has less spatial resolution than IVUS, can adequately measure the critical local biomechanical and anatomic variables. Aim: To compare the accuracy of ESS computation of local ESS metrics by non-invasive CCTA vs invasive IVUS imaging. Methods: We analyzed 30 arteries (22 LAD, 4 LCx,4 RCA) from 30 patients selected from a registry of patients who underwent both IVUS and CCTA of the same artery for suspected CAD. CCTA images were acquired using a CCTA with either 64 or 256 detector rows. We segmented lumen, vessel, and plaque areas with both IVUS (manual segmentation) and CCTA (AI based software; Cleerly Inc, NY). Co-registration of IVUS and CCTA Images was performed using fiduciary anatomic landmarks. Images from IVUS and CCTA were used to generate a 3-D arterial reconstruction, and local ESS distribution was assessed by computational fluid dynamics and reported in consecutive 3-mm segments. Results: Table Conclusion: Compared to IVUS values, 256-slice is more accurate than 64-slice CCTA to measure lumen and vessel areas, but computation of detailed local ESS (average, low and high) is similar by both CCTA methods. Local ESS evaluation using non-invasive CCTA is feasible and comparable to invasive gold standard IVUS and is suitable to characterize the local flow patterns that play an important role in plaque development, progression, and destabilization

Extrinsic compression of coronary and pulmonary vasculature.

Coronary artery disease from atherosclerosis induced stenosis remains the leading cause of acute coronary syndrome (ACS) and death worldwide, however extrinsic compression of coronary arteries from adjacent anatomical and pathological structures is an infrequent but important diagnosis to be aware of, especially given the nonspecific symptoms of chest pain that mimic angina in patients with pulmonary hypertension (PHT) and congenital heart disease. Non-invasive CT angiography is an invaluable diagnostic tool for detection of coronary artery compression, pulmonary artery dilatation and pulmonary vascular compression. Although established guidelines are not available for management of left main coronary artery (LMCA) compression syndrome, percutaneous coronary intervention and stent implantation remain a feasible option for the treatment, specifically for patients with a high surgical risk. Treatment of pulmonary vein or artery compression is more varied and determined by etiology. This review article is focused on detailed discussion of extrinsic compression of coronary arteries, mainly the LMCA and brief discussion on pulmonary vasculature compression by surrounding anatomical and pathological entities, with focus on pathophysiology, clinical features, complications and role of imaging in its diagnosis and management.

Whipple procedure for ampulla of Vater cancer in a patient with situs inversus (clinical case)

A clinical case of a rare combination of complete transposition of internal organs (situs inversus totalis) with adenocarcinoma of the major duodenal papilla is presented. In addition to situs vicserum inversus, the patient has a special variant of vascular anatomy that is not included in the generally accepted classification of variants of arterial liver anatomy according to Michaels N.A. (1955), namely: separate separation of the left and right hepatic arteries from the ventral trunk. After individual preoperative planning, a patient with a complete reverse position of the abdominal organs and non-standard vascular anatomy was performed Whipple procedure. Non-invasive CT angiography is important in a complex preoperative examination, which allows timely identification and clarification of frequently occurring features of blood supply to the hepatopancreatoduodenal zone in patients with situs inversus totalis. Such surgical interventions should be performed in large multi-specialty medical centers that have extensive experience in performing pancreatoduodenal resections.

Coronary Computed Tomography Angiography for Assesment of Stable Coronary Artery Disease – a Cost-effectiveness Perspective

Abstract Patients with chest pain presenting to the emergency room are currently investigated using either invasive coronary angiography (ICA) or noninvasive coronary computed tomography angiography (CCTA). ICA remains an expensive diagnostic tool and exposes patients to a high risk of periprocedural complication. Besides the currently available expansive economic evidence, there is still an important lingering issue: to establish, from the healthcare provider’s point of view, which is the most cost-effective investigation tool for the detection of significant coronary artery disease. The aim of this article is to present the latest developments in the field of imaging tools for the detection of coronary atherosclerosis in patients with chest pain, from the perspective of a cost-effectiveness analysis.

Abstract P321: The Cerebral Collateral Cascade: Rethinking the Assessment of Vascular Pathways in Acute Ischemic Stroke Patients

Background and Purpose: Robust collateral blood flow in patients with acute ischemic stroke due to large vessel occlusion (AIS-LVO) has been correlated with favorable outcomes. Collaterals are commonly assessed by the number of arteries present on non-invasive CT angiography (CTA) overlying ischemic brain, but blood transit from these arteries through the brain tissue and the venous drainage is not assessed by this technique. We hypothesized that a comprehensive imaging analysis of the cerebral collateral cascade (CCC) would predict clinical and radiological outcomes in patients with AIS-LVO patients. Materials and Methods: Multicenter retrospective cohort study of AIS-LVO patients undergoing thrombectomy triage. CCC was determined on pre-treatment imaging by scoring for pial arterial collaterals, tissue-level collaterals (TLC), and venous outflow. Pial arterial collaterals were determined by CTA (Tan scale), TLC were assessed on CT perfusion data using the Hypoperfusion Intensity Ratio, and venous egress was assessed on CTA using the cortical vein opacification score system. 3 groups were defined: CCC+ (good pial collaterals, TLC, and venous perfusion), CCC- (poor pial collaterals, TLC, and venous perfusion) and CCCmixed (reminder of patients). Primary outcome was a good functional outcome (modified Rankin Scale [mRS] 0-2 at 90 days). Secondary outcome was final infarct volume. Results: 647 patients met inclusion criteria: 176 CCC+, 345 CCCmixed and 126 CCC-. Multivariate ordinal logistic regression showed that CCC+ predicted good functional outcomes (mRS 0-2: OR=20.8 [95% CI 9.3-46.8]; p&lt;0.001) compared to CCC- and CCCmixed. CCCmixed (β: 27.1, SE: 7.7; p&lt;0.001) and CCC- (β: 86.6, SE: 9.9; p&lt;0.001) profiles were associated with higher final infarct volumes after treatment compared to CCC+. Conclusion: Comprehensive assessment of the collateral blood flow cascade in AIS-LVO patients is a strong predictor of clinical and radiological outcomes in AIS-LVO patients.

Abstract 17031: Noninvasive CT-Based Hemodynamic Assessment Using 3D Printing and Virtual Functional Assessment Index

Background: Virtual functional assessment index (vFAI), an alternative approach for assessing hemodynamic significance of stenosis has been shown to enhance the diagnostic performance of coronary computed tomography angiography (CCTA) based on evaluating the area under pressure drop-flow curve for a stenosis. Previously, this was assessed via computational fluid dynamics. We investigated the evaluation of vFAI from CCTA images using 3D printing and an in vitro flow loop and its efficacy as compared to the invasively measured fractional flow reserve (FFR). Methods and Results: Eighteen patients with varying degrees of coronary artery disease who underwent non-invasive CCTA scans and invasive FFR of their left anterior descending coronary artery (LAD) were included. The LAD artery was segmented and reconstructed using Mimics (Materialise inc.,). The segmented models were then 3D printed using Carbon 3D printer (Carbon Inc.,) with rigid resins. An in vitro flow circulation system representative of invasive measurements in a cardiac catheterization laboratory was developed to experimentally evaluate the hemodynamic parameters of pressure and flow (Fig A). For each model, a range of physiological flow rates was applied by a peristaltic steady flow pump and titrated by a flow sensor. The pressure drop and the pressure ratio (Pd/Pa) were assessed for patient-specific aortic pressure and differing flow rates. vFAI was evaluated as the normalized area under the P d /P a vs Q curve from 0 to 240 mL/min. There was a strong correlation between vFAI and FFR, (R = 0.83, p &lt; 0.001; Fig B) and a very good agreement between the two parameters by Bland-Altman analysis. The mean difference of measurements from the two methods was 0.06 (SD = 0.08, p=0.0063; Fig C), indicating a small systematic overestimation of the FFR by vFAI. Conclusions: vFAI can be effectively derived from 3D CTCA datasets using 3D-printed in vitro models, based on evaluation over a range of hemodynamic conditions.

A novel arterial redox-specific machine learning-derived radiomic signature of perivascular adipose tissue predicts cardiac mortality from routine CCTA

Abstract Background Vascular oxidative stress is involved in inflammation and atherogenesis. Vascular inflammation induces spatial changes in perivascular adipose tissue (PVAT) composition, which can be detected by radiomic analysis of coronary computed tomography angiography (CCTA) images. Purpose To explore the association of arterial oxidative stress with long-term risk of major adverse cardiovascular events (MACE). To develop a radiomic signature to identify high oxidative stress non-invasively using CCTA. Finally, to assess the ability of this signature to predict future cardiac risk. Methods Arm 1 included 272 patients undergoing cardiac surgery. Segments of internal mammary artery (IMA) were used for ex-vivo quantification of NADPH-stimulated and Vas2870 (pan-NOX inhibitor) inhibitable superoxide production by lucigenin-enhanced chemiluminescence. Eighty-two of these patients with CCTA scans available constituted Arm 2. Peri-IMA PVAT was segmented and used to extract 1,616 radiomic features, which, after filtering (40 final features), were utilised to train extreme gradient boosting, a machine learning algorithm, to predict high arterial oxidative stress. Arm 3 included a nested cohort of 308 participants (41 suffering cardiac death and 267 matched controls) from the CRISP-CT (Cardiovascular RISk Prediction using Computed Tomography) study to externally validate the redox-specific signature developed in Arm 2 for cardiac risk prediction. Results Over a median follow-up of 40 months, 18 (6.6%) MACE (cardiovascular death, non-fatal myocardial infarction, and stroke) occurred in Arm 1. High arterial NADPH-stimulated superoxide was independently associated with MACE risk (Adj. HR[95% CI]: 1.61 [1.04–2.53] per SD, p=0.03, adjusted for age, sex, diabetes, hypertension, hyperlipidemia, smoking, obesity, and plasma TNFa). Unsupervised hierarchical clustering of radiomic features from peri-IMA PVAT segments in Arm 2 identified two distinct clusters (A) that differed in NADPH stimulated (p=0.01) and Vas2870 inhibitable (p=0.04) IMA superoxide (B), supporting the hypothesis that PVAT mapping can capture changes corresponding to differential levels of underlying vascular redox state. This prompted the development of a radiomic signature specific to PVAT alterations associated with high vascular oxidative stress, which was validated in Arm 3 (AUC:0.61, p=0.026, C). The novel signature was able to stratify cardiac risk in the validation set, independently of the Fat Attenuation Index, epicardial adipose tissue volume, high-risk plaque features, and obstructive CAD (Adj. HR [95% CI]:2.56 [1.35–4.87], p=0.004, D). Conclusion Increased arterial oxidative stress predicts cardiac risk in patients with advanced atherosclerosis. We present for the first time a novel, non-invasive CCTA imaging biomarker reflecting changes in vascular redox state by radiomic phenotyping of perivascular space, which stratifies cardiac risk beyond standard and newer risk assessment methods. Funding Acknowledgement Type of funding source: Foundation. Main funding source(s): British Heart Foundation, National Institute of Health Research, Oxford Biomedical Research Centre

Validation of Wall Shear Stress Assessment in Non-invasive Coronary CTA versus Invasive Imaging: A Patient-Specific Computational Study.

Endothelial shear stress (ESS) identifies coronary plaques at high risk for progression and/or rupture leading to a future acute coronary syndrome. In this study an optimized methodology was developed to derive ESS, pressure drop and oscillatory shear index using computational fluid dynamics (CFD) in 3D models of coronary arteries derived from non-invasive coronary computed tomography angiography (CTA). These CTA-based ESS calculations were compared to the ESS calculations using the gold standard with fusion of invasive imaging and CTA. In 14 patients paired patient-specific CFD models based on invasive and non-invasive imaging of the left anterior descending (LAD) coronary arteries were created. Ten patients were used to optimize the methodology, and four patients to test this methodology. Time-averaged ESS (TAESS) was calculated for both coronary models applying patient-specific physiological data available at the time of imaging. For data analysis, each 3D reconstructed coronary artery was divided into 2mm segments and each segment was subdivided into 8 arcs (45°).TAESS and other hemodynamic parameters were averaged per segment as well as per arc. Furthermore, the paired segment- and arc-averaged TAESS were categorized into patient-specific tertiles (low, medium and high). In the ten LADs, used for optimization of the methodology, we found high correlations between invasively-derived and non-invasively-derived TAESS averaged over segments (n=263, r=0.86) as well as arcs (n=2104, r=0.85, p<0.001). The correlation was also strong in the four testing-patients with r=0.95 (n=117 segments, p=0.001) and r=0.93 (n=936 arcs, p=0.001).There was an overall high concordance of 78% of the three TAESS categories comparing both methodologies using the segment- and 76% for the arc-averages in the first ten patients. This concordance was lower in the four testing patients (64 and 64% in segment- and arc-averaged TAESS). Although the correlation and concordance were high for both patient groups, the absolute TAESS values averaged per segment and arc were overestimated using non-invasive vs. invasive imaging [testing patients: TAESS segment: 30.1(17.1-83.8) vs. 15.8(8.8-63.4) and TAESS arc: 29.4(16.2-74.7) vs 15.0(8.9-57.4) p<0.001]. We showed that our methodology can accurately assess the TAESS distribution non-invasively from CTA and demonstrated a good correlation with TAESS calculated using IVUS/OCT 3D reconstructed models.

Role of Computed Tomography Angiography in Setting of Spontaneous Coronary Artery Dissection

Spontaneous coronary artery dissection (SCAD) is an infrequent cause of acute coronary syndrome, predominantly affecting young women. Catheter-based coronary angiography is the gold standard diagnostic test, especially when coupled with intracoronary imaging. Conservative management in stable patients is the preferred approach given the increased risk of complications associated with percutaneous interventions. Noninvasive coronary computed tomography angiography (CTA) has a potential role in the diagnosis and follow-up of SCAD. CTA also plays a role in screening for extracoronary vascular abnormalities frequently associated with SCAD. The goal of this article is to review the potential role of CTA in evaluating SCAD.

Endothelial Shear Stress Calculation In Human Coronary Arteries: Comparison Between 3d Reconstructions Based On Invasive And Noninvasive Imaging.

Introduction: Low endothelial shear stress (ESS) is associated with coronary plaque progression. Classically ESS has been assessed using computational fluid dynamics (CFD) based on 3D geometries reconstructed from invasive intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Recent advances allow to calculate ESS based on noninvasive coronary computed tomography angiography(CTA) imaging. In a two-center study, we have developed an optimized methodology to accurately study ESS calculations based on 3D reconstructions using CTA and compare to the gold standard that fuses higher resolution invasive imaging with CTA.

Non-Invasive Functional Coronary Artery Evaluation by CT-Derived Fractional Flow Reserve (FFRct) in Heart Transplant Patients

Invasively measured fractional flow reserve (FFR) is associated with outcome in heart transplant (HTx) patients. Non-invasive coronary computed tomography angiography (CCTA)-derived FFR (FFRct) provides additional functional information from anatomical CT images. The anatomical model of the coronary arteries derived from CCTA is used to calculate the FFRct values at each point in the coronary arteries. We describe the first use of FFRct in a cohort of HTx patients. HTx patients underwent CCTA with FFRct as part routine follow-up to screen for cardiac allograft vasculopathy (CAV). FFRct was performed off-site by a company. FFRct was measured distal to each coronary stenosis >30% and at the most distal location of each of the 3 major coronary arteries (right, left anterior descending and circumflex coronary artery). Overal distal FFRct was calculated as the mean of 3 vessels per patient. During 90-day follow-up, performance of additional tests for coronary assessment and revascularization were recorded. 73 patients (age 56 (42-65) years, 63% males) at 11 (8-16) years after HTx were included. In the 54 patients without a hemodynamically significant focal FFRct stenosis (FFRct >0.80), the distal left anterior descending artery FFRct was <0.90 in 72% of patients and 9 (17%) patients had ≥1 coronary artery with a distal FFRct ≤0.8, including 1 patient with a distal FFRct ≤0.8 in all coronary vessels. Overall distal FFRct values were 0.88 (0.86-0.91) (median, 25 - 75 percentile), 0.87 (0.86-0.90), and 0.89 (0.86-0.91) at 5-9, 10-14 or ≥15 years after transplantation, respectively (p=0.89). Additional tests were performed in 12 (16%) patients, which resulted in revascularization in 7 (10%) patients. FFRct was successfully performed on CCTA scans of HTx patients and demonstrated that more than a quarter of patients had a focal coronary stenosis with FFRct ≤0.8. Even in the absence of a focal stenosis FFRct values are often abnormal in HTx patients.