Assessment of New Coronary Features on Quantitative Coronary Angiographic Images With Innovative Unsupervised Artificial Adaptive Systems: A Proof-of-Concept Study.

Background and Purpose: The Active Connection Matrixes (ACMs) are unsupervised artificial adaptive systems able to extract from digital images features of interest (edges, tissue differentiation, etc.) unnoticeable with conventional systems. In this proof-of-concept study, we assessed the potentiality of ACMs to increase measurement precision of morphological structures (e.g., stenosis and lumen diameter) and to grasp morphological features (arterial walls) from quantitative coronary angiography (QCA), unnoticeable on the original images. Methods: Archive images of QCA and intravascular ultrasound (IVUS) of 10 patients (8 men, age 69.1 ± 9.7 years) who underwent both procedures for clinical reasons were retrospectively analyzed. Arterial features derived from "IVUS images," "conventional QCA images," and "ACM-reprocessed QCA images" were measured in 21 coronary segments. Portions of 1-mm length (263 for lumen and 526 for arterial walls) were head-to-head compared to assess quali-quantitative between-methods agreement. Results: When stenosis was calculated on "ACM-reprocessed QCA images," the bias vs. IVUS (gold standard) did not improve, but the correlation coefficient of the QCA-IVUS relationship increased from 0.47 to 0.83. When IVUS-derived lumen diameters were compared with diameters obtained on ACM-reprocessed QCA images, the bias (-0.25 mm) was significantly smaller (p < 0.01) than that observed with original QCA images (0.58 mm). ACMs were also able to extract arterial wall features from QCA. The bias between the measures of arterial walls obtained with IVUS and ACMs, although significant (p < 0.01), was small [0.09 mm, 95% CI (0.03, 0.14)] and the correlation was fairly good (r = 0.63; p < 0.0001). Conclusions: This study provides proof of concept that ACMs increase the measurement precision of coronary lumen diameter and allow extracting from QCA images hidden features that mirror well the arterial walls derived by IVUS.

Association of lifelong occupation and educational level with subclinical atherosclerosis in different European regions. Results from the IMPROVE study.

BACKGROUND AND AIMS: We aimed to examine the association between socioeconomic status (SES) and subclinical atherosclerosis, as assessed by carotid intima-media-thickness (C-IMT) and to investigate whether the effect of social inequality on C-IMT is mediated by cardiovascular (CV) risk factors and whether it is dissimilar in men and women, and in different European countries. METHODS: We assessed the association of lifelong occupation and educational level with C-IMT in the IMPROVE study cohort including 3703 subjects (median age 64.4 years; 48% men) from Southern (Italy), Western (France and the Netherlands) and Northern Europe (Finland and Sweden). Three summary measures of C-IMT (IMTmean, IMTmax, IMTmean-max), obtained from four segments of both carotids, were considered. RESULTS: After adjusting for conventional CV risk factors, current employment status and diet, C-IMT was higher in manual workers than in white collars (+7.7%, +5.3%, +4.6% for IMTmax, IMTmean-max and IMTmean, respectively; all p<.0001). Similar results were obtained by stratification for educational level. The effect of occupation on C-IMT was comparable in men and women and in different age groups, and was only partially mediated by differences in CV risk factors. Of note, the association of C-IMT with occupation was significant in Western and Northern Europe but not in Italy, with a significant statistical interaction (p = .0005). CONCLUSIONS: Low SES was associated with subclinical atherosclerosis in subjects with at least three CV risk factors. Such association was stronger in Northern and Western Europe than in Italy. This difference was not completely explained by inequalities in CV risk factors and behavioural variables.

Carotid plaque-thickness and common carotid IMT show additive value in cardiovascular risk prediction and reclassification.

BACKGROUND AND AIMS: Carotid plaque size and the mean common carotid intima-media thickness measured in plaque-free areas (PF CC-IMTmean) have been identified as predictors of vascular events (VEs), but their complementarity in risk prediction and stratification is still unresolved. The aim of this study was to evaluate the independence of carotid plaque thickness and PF CC-IMTmean in cardiovascular risk prediction and risk stratification. METHODS: The IMPROVE-study is a European cohort (n = 3703), where the thickness of the largest plaque detected in the whole carotid tree was indexed as cIMTmax. PF CC-IMTmean was also assessed. Hazard Ratios (HR) comparing the top quartiles of cIMTmax and PF CC-IMTmeanversus their respective 1-3 quartiles were calculated using Cox regression. RESULTS: After a 36.2-month follow-up, there were 215 VEs (125 coronary, 73 cerebral and 17 peripheral). Both cIMTmax and PF CC-IMTmean were mutually independent predictors of combined-VEs, after adjustment for center, age, sex, risk factors and pharmacological treatment [HR (95% CI) = 1.98 (1.47, 2.67) and 1.68 (1.23, 2.29), respectively]. Both variables were independent predictors of cerebrovascular events (ischemic stroke, transient ischemic attack), while only cIMTmax was an independent predictor of coronary events (myocardial infarction, sudden cardiac death, angina pectoris, angioplasty, coronary bypass grafting). In reclassification analyses, PF CC-IMTmean significantly adds to a model including both Framingham Risk Factors and cIMTmax (Integrated Discrimination Improvement; IDI = 0.009; p = 0.0001) and vice-versa (IDI = 0.02; p < 0.0001). CONCLUSIONS: cIMTmax and PF CC-IMTmean are independent predictors of VEs, and as such, they should be used as additive rather than alternative variables in models for cardiovascular risk prediction and reclassification.

Assessment and relevance of carotid intima-media thickness (C-IMT) in primary and secondary cardiovascular prevention.

Interventions aimed to prevent cardiovascular diseases (CVD) are more effective if administered to subjects carefully selected according to their CVD risk. Usually, this risk is evaluated on the basis of the presence and severity of conventional vascular risk factors (VRFs); however, atherosclerosis, the main pathologic substrate of CVD, is not directly revealed by VRFs. The measurement of the arterial wall, using imaging techniques, has increased the early identification of individuals prone to develop atherosclerosis and to quantify its changes over time. B-mode ultrasound is a technique which allows a non-invasive assessment of the arterial wall of peripheral arteries (e.g. extracranial carotid arteries), and provides measures of the intima-media thickness complex (C-IMT) and additional data on the occurrence, localization and morphology of plaques. Being an independent predictor of vascular events, C-IMT has been considered as a tool to optimize the estimation of CVD risk but this application is still a matter of debate. Though the technique is innocuous, relatively inexpensive and repeatable, its use in the clinical practice is limited by the lack of standardized protocols and clear guidelines. This review outlines the rationale for the potential use of C-IMT in the stratification of cardio- and cerebro-vascular risk and discusses several topics related to the measurement of this variable, which are still controversial among experts of the field.