Coronary risk factors and coronary atheroma burden at severely narrowing segments

Aortic Arch Calcification Is a Strong Predictor of the Severity of Coronary Artery Disease in Patients with Acute Coronary Syndrome

BACKGROUND

The purpose of this study was to investigate the correlation of the extent of aortic arch calcification (AAC) detectable on chest X-rays with the severity of coronary artery disease (CAD) as evaluated by the SYNTAX score (SS) in patients with acute coronary syndrome (ACS).

METHODS

A total of 1,418 patients (344 women; 59 ± 10 years) who underwent coronary angiography for ACS and were treated with coronary revascularization were included in the present study; chest X-rays were performed on admission. The AAC extent was divided into four grades (0-3). SS was calculated based on each patient's coronary angiographic findings. The relationship between the AAC extent and SS was assessed.

RESULTS

The AAC extent was positively correlated with SS (ρ = 0.639, P < 0.001). In the multivariate analysis, compared with grade 0, odds ratios (ORs) of AAC grades 1, 2, and 3 in predicting SS >22 were 12.95 (95% CI, 7.85-21.36), 191.76 (95% CI, 103.17-356.43), and 527.81 (95% CI, 198.24-1405.28), respectively. Receiver operating characteristic curve analysis yielded a strong predictive ability of the AAC extent for SS >22 (area under curve = 0.840, P < 0.001). Absence of AAC had a sensitivity, specificity, positive prognostic value, negative prognostic value, and accuracy of 46.7%, 95.9%, 94.1%, 56.4%, and 67.3%, respectively, for SS ≤22. AAC grades ≥2 had a sensitivity of 66.3%, specificity of 89.2%, positive prognostic value of 81.5%, negative prognostic value of 78.6%, and accuracy of 79.6% for the correct identification of SS >22.

CONCLUSIONS

The extent of AAC detectable on chest X-rays might provide valuable information in predicting CAD severity in ACS patients.

Risk factors of atherosclerotic tissue types in single-vessel and intermediate coronary lesions: a cross-sectional study

BACKGROUND

Few data exist that correlate lesion-related risk factors such as conventional cardiovascular risks or lipoprotein-associated phospholipase A2 (Lp-PLA2) with tissue types within atherosclerotic plaques in patients with single-vessel and intermediate coronary lesions.

METHODS

One hundred and ninety-two patients with single-vessel and intermediate coronary lesions were enrolled in a cross-sectional study and divided into two groups: stable angina pectoris (SAP) and acute coronary syndrome (ACS) groups. Data regarding clinical characteristics and Lp-PLA2 mass were collected. Using iMAP-IVUS, lumen areas were manually traced to determine the minimum lumen area (MLA) at 1-mm intervals in diseased segments. At the minimum lumen lesion, areas of different types of atherosclerotic tissue [i.e., areas of fibrous plaque tissue (FP), fibro-fatty tissue (FF), dense calcium (DC) and necrotic core (NC)], vascular external elastic membrane (EEMCSA) and plaque and media (P&MCSA) were calculated using the built-in iMap algorithm. Plaque burden was computed as P&MCSA divided by EEMCSA.

RESULTS

In a univariate analysis, glycosylated hemoglobin A1C (GHbA1C), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), hypertension, Lp-PLA2 and a history of taking statins predicted the degree of FP and NC area, as well as plaque burden, but were not significant predictors of FF or DC area. In a multivariate analysis, Lp-PLA2 and HbA1c remained independent predictors of plaque burden, FP and NC area. However, the results of the regression analyses were not identical when the SAP and ACS groups were analyzed separately. Lp-PLA2, diabetes and NC area were significant predictors of acute coronary lesions, and the predictive value of Lp-PLA2 was confirmed by the finding of a high area-under-the-curve in a ROC analysis (0.837, 95% CI:0.778-0.895, P = 0.000), as well as by the reasonable sensitivity and specificity of cut-off values.

CONCLUSIONS

GHbA1C and Lp-PLA2 were strong independent predictors of plaque burden and FP and NC area at the minimum lumen lesion in patients with single-vessel and intermediate coronary lesions. Furthermore, Lp-PLA2 has a certain predictive value for acute coronary lesions.

Automated tracing of the adventitial contour of aortoiliac and peripheral arterial walls in CT angiography (CTA) to allow calculation of non-calcified plaque burden

Aortoiliac and lower extremity arterial atherosclerotic plaque burden is a risk factor for the development of visceral and peripheral ischemic and aneurismal vascular disease. While prior research allows automated quantification of calcified plaque in these body regions using CT angiograms, no automated method exists to quantify soft plaque. We developed an automatic algorithm that defines the outer wall contour and wall thickness of vessels to quantify non-calcified plaque in CT angiograms of the chest, abdomen, pelvis, and lower extremities. The algorithm encodes the search space as a constrained graph and calculates the outer wall contour by deriving a minimum cost path through the graph, following the visible outer wall contour while minimizing path tortuosity. Our algorithm was statistically equivalent to a reference standard made by two reviewers. Absolute error was 1.9 ± 2.3% compared to the inter-observer variability of 3.9 ± 3.6%. Wall thickness in vessels with atherosclerosis was 3.4 ± 1.6 mm compared to 1.2 ± 0.4 mm in normal vessels. The algorithm shows promise as a tool for quantification of non-calcified plaque in CT angiography. When combined with previous research, our method has the potential to quantify both non-calcified and calcified plaque in all clinically significant systemic arteries, from the thoracic aorta to the arteries of the calf, over a wide range of diameters. This algorithm has the potential to enable risk stratification of patients and facilitate investigations into the relationships between asymptomatic atherosclerosis and a variety of behavioral, physiologic, pathologic, and genotypic conditions.

Total Cholesterol Content of Erythrocyte Membranes and Coronary Atherosclerosis: An Intravascular Ultrasound Pilot Study

Background: Increasing evidence suggests that erythrocytes may participate in atherogenesis. We sought to investigate the relationship between total cholesterol content in erythrocyte membranes (CEM) and coronary atheroma burden in patients with coronary artery disease (CAD). Methods: We prospectively enrolled 28 participants: 11 patients with angiographically significant CAD and 17 controls. Intravascular ultrasound (IVUS) and 3-dimensional reconstruction of coronary arteries was performed in the patient subgroup. Results: Cholesterol content of erythrocyte membranes was higher in patients compared to controls (P < .01). Cholesterol content of erythrocyte membranes correlated with total atheroma volume (r = .82, P < .01) and with percentage plaque area at the vessel site with minimal lumen area (r = .75, P < .05). On multivariate analysis, CEM was the only variable independently predicting total atheroma volume (P = .05). Conclusions: This pilot study is the first to demonstrate a significant relation between CEM and coronary atherosclerotic burden, suggesting a possible role of erythrocyte membrane—derived lipids in the expansion of atheromata. The results merit validation in larger studies.

Traditional Risk Factors Are Predictive on Segmental Localization of Coronary Artery Disease

The aim of this study was to investigate the relationship between established risk factors and segmental localization of coronary artery disease. A total of 2760 patients who underwent coronary angiography were enrolled into the study. Coronary angiographic segmental evaluation was performed according to the scheme of American Heart Association. Patients were classified into 2 groups (group 1: normal coronary artery segments, group 2: coronary artery segments with coronary artery disease). Smoking was highly related with left main coronary artery disease (odds ratio = 7.5; P = .005). Diabetes mellitus and male sex increased the risk of atherosclerosis in all coronary vasculature (odds ratio = 2.7-2.2; P < .001- P < .001). Hypertension was correlated with distal coronary artery (odds ratio = 1.4; P < .001) and family history with distal circumflex lesions (odds ratio = 4.5; P = .005) High triglyceride levels were associated with right coronary artery lesions (odds ratio = 1.00; P =.03). The effect of advanced age was small (odds ratio = 1.08; P < .001). Risk factors may be predictive for segmental localization.