BACKGROUND. Coronary artery calcium (CAC) scoring is used to stratify acute coronary syndrome (ACS) risk. Nonetheless, patients with a CAC score of zero (CAC0) remain at risk from noncalcified plaque components. OBJECTIVE. The purpose of this study was to explore CTA-derived coronary artery plaque characteristics in symptomatic patients with CAC0 who subsequently have ACS through comparisons with patients with a CAC score greater than 0 (CAC> 0) who subsequently have ACS as well as with patients with CAC0 who do not subsequently have ACS. METHODS. This study entailed a secondary retrospective analysis of prior prospective registry data. The international multicenter CONFIRM (Coronary CT Angiography Evaluation for Clinical Outcomes: An International Multicenter) registry collected longitudinal observational data on symptomatic patients who underwent clinically indicated coronary CTA from January 2004 to May 2010. ICONIC (Incident Coronary Syndromes Identified by CT) was a nested cohort study conducted within CONFIRM that identified patients without known coronary artery disease (CAD) at the time of CTA who did and did not subsequently have ACS (i.e., the ACS and control groups, respectively) and who were propensity matched in a 1:1 ratio on the basis of CAD risk factors and CAD severity on CTA. The present ICONIC substudy selected matched patients in the ACS and control groups who both had documented CAC scores. CTA examinations were analyzed using artificial intelligence software for automated quantitative plaque assessment. In the ACS group, invasive angiography findings were used to identify culprit lesions. RESULTS. The present study included 216 patients (mean age, 55.6 years; 91 women and 125 men), with 108 patients in each of the ACS and control groups. In the ACS group, 23% (n = 25) of patients had CAC0. In the ACS group, culprit lesions in the subsets of patients with CAC0 and CAC> 0 showed no significant differences in fibrous, fibrofatty, or necrotic-core plaque volumes (p > .05). In the CAC0 subset, patients with ACS, compared with control patients, had greater mean (± SD) fibrous plaque volume (29.4 ± 42.0 vs 5.5 ± 15.2 mm3, p < .001), fibrofatty plaque volume (27.3 ± 52.2 vs 1.3 ± 3.7 mm3, p < .001), and necrotic-core plaque volume (2.8 ± 6.4 vs 0.0 ± 0.1 mm3, p < .001). CONCLUSION. After propensity-score matching, 23% of patients with ACS had CAC0. Patients with CAC0 in the ACS and control groups showed significant differences in volumes of noncalcified plaque components. CLINICAL IMPACT. Methods that identify and quantify noncalcified plaque forms may help characterize ACS risk in symptomatic patients with CAC0.

Pre-procedural imaging is critical for transcatheter mitral valve repair planning in patients with mitral valve disease. As differences among various measurement techniques for valve evaluation are still poorly understood, we sought to assess the intra- and interobserver agreement of complex measurements derived from a prototype mitral evaluation tool (Siemens) and a commercially available tool (CVI42) using both saddle- and D-shaped mitral annulus techniques. Multiphasic cardiac computed tomography angiography data were loaded into each software. Three expert readers independently measured the annuli on systolic- and diastolic-phase images using both tools. Measurement agreement between the tools was assessed with t tests, with p ≤ 0.05 considered statistically significant. Intraclass correlation coefficient (ICC) was used for interobserver agreement. Bland–Altman plots were used to assess for systematic differences. Ten patients (mean age: 61.9 ± 9.9 years, 70

INTRODUCTION: Coronary CT angiography (CCTA) is a powerful noninvasive tool for identifying high-risk plaque, such as low-density non-calcified plaque (LD-NCP). Though, the optimal treatment of patients with LD-NCP remains unclear. This study explored the association of revascularization in the setting of LD-NCP with the occurrence of acute coronary syndrome (ACS). Methods: This was a post-hoc analysis of the ICONIC study. A subset of 234 patients that underwent CCTA with subsequent ACS were matched to 234 control patients who also underwent CCTA but did not have ACS during follow-up. Patients were also followed for occurrence of revascularization, either coronary artery bypass graft or percutaneous coronary intervention. Atherosclerosis imaging-enabled quantitative CT (AI-QCT) was used to measure diameter stenosis, and LD-NCP, non-calcified plaque, and calcified plaque volumes from each CCTA. LD-NCP was defined as plaque with -190 to 30 Hounsfield Units. Patients were stratified based on the presence of LD-NCP. Subgroup analysis was conducted to compare the occurrence of ACS with the rate of revascularization. Kaplan-Meier survival curves and extended Cox regression analysis were used to evaluate the effect size of revascularization and LD-NCP on occurrence of ACS. Results: AI-QCT was completed in 448/468 subjects (follow-up time [MEAN±SD] 2.44±2.48 years). The median of LD-NCP was 1.2 mm 3 for patients with >0 mm 3 LD-NCP. There were 85 patients with LD-NCP >1.2 mm 3 and 363 patients with LD-NCP ≤1.2 mm 3 . In patients with LD-NCP >1.2 mm 3 , the rate of revascularization in patients with and without ACS was 3/52 (5.8%) versus 14/33 (42.4%) (p<0.001). In patients with LD-NCP ≤1.2 mm 3 , the rate of revascularization in patients with and without ACS was 36/170 (21.2%) versus 39/193 (20.2%) (p=0.897). In comparison to patients without revascularization and LD-NCP ≤1.2 mm 3 , patients with LD-NCP >1.2 mm 3 and revascularization were less likely to have ACS during follow-up (adjusted HR: 0.20 [0.07, 0.61]; p=0.005). Additionally, patients with LD-NCP >1.2 mm 3 who did not undergo revascularization were more likely to have ACS (adjusted HR: 1.47 [1.03, 2.12]; p=0.036). Hazard ratios were adjusted for diameter stenosis, and non-calcified and calcified plaque volume. Time-dependent coefficients were included for diameter stenosis. Conclusion: Revascularization of patients with LD-NCP >1.2 mm 3 identified on CCTA with AI-QCT was associated with less risk for ACS.

Donor-derived cell-free DNA (dd-cfDNA) may safely assess kidney allograft rejection. Molecular Microscope (MMDx®) gene expression may offer increased precision to histology. This single-center retrospective study monitored kidney transplant recipients for rejection at specified time intervals by utilizing creatinine (SCr), proteinuria, donor-specific antibodies (DSAs), and dd-cfDNA. A clinically indicated biopsy sample was sent for histopathology and MMDx®. Patients were categorized into rejection (Rej) and non-rejection (NRej) groups, and further grouped according to antibody-mediated rejection (ABMR) subtypes. Rej and NRej groups included 52 and 37 biopsies, respectively. Median follow-up duration was 506 days. DSAs were positive in 53% and 22% of patients in both groups, respectively (p = 0.01). Among these groups, pre- and post-intervention median SCr, proteinuria, and dd-cfDNA at 1 month, 2 months, and at the last follow-up revealed significant difference for dd-cfDNA (all p = 0.01), however, no difference was found for SCr and proteinuria (p > 0.05). The AUC was 0.80 (95% CI: 0.69–0.91), with an optimal dd-cfDNA criterion of 2.2%. Compared to histology, MMDx® was more likely to diagnose ABMR (79% vs. 100%) with either C4d positivity or negativity and/or DSA positivity or negativity. Hence, a pre- and post-intervention allograft monitoring protocol in combination with dd-cfDNA, MMDx®, and histology has aided in early diagnosis and timely individualized intervention.

Rizvi, Asim; Hussain, Syed A.; Mujtaba, Muhammad A.; Lea, Alfred S.; Kueht, Michael; Gamilla-Crudo, Ann Kathleen N. Author Information

Rizvi, Asim; Hussain, Syed A.; Gamilla-Crudo, Ann Kathleen N.; Kueht, Michael; Mujtaba, Muhammad A. Author Information