Association of calcium density in the thoracic aorta with risk factors and clinical events.

OBJECTIVES: In the ascending aorta, calcification density was independently and inversely associated with cardiovascular disease (CVD) risk prediction. Until now, the density of thoracic aorta calcium (TAC) was estimated as the Agatston score divided by the calcium area (DAG). We thought to analyze TAC density in a full Hounsfield unit (HU) range and to study its association with TAC volume, traditional risk factors, and CVD events. METHODS: Non-enhanced CT images of 1426 patients at intermediate risk were retrospectively reviewed. A calcium density score was estimated as the average of the maximum HU attenuation in all calcified plaques of the entire thoracic aorta (DAV). RESULTS: During a mean 4.0 years follow-up, there were 26 events for a total of 674 patients with TAC > 0. TAC volume and DAV were positively correlated (R = 0.72). The median DAV value was 457 HU (IQ 323-603 HU) and was exponentially related to DAG (R = 0.86). DAV was inversely associated with systolic pressure (p < 0.05), pulse pressure (p < 0.01), hypertension (p < 0.05), and 10-year FRS (p < 0.001) after adjusting for TAC volume. When TAC volume and DAV were included in a logistic model, a significant improvement was shown in CVD risk estimation beyond coronary artery calcium (CAC) (AUC = 0.768 vs 0.814, p < 0.05). In multivariable Cox models, TAC volume and DAV showed an independent association with CVD. CONCLUSIONS: In intermediate risk patients, TAC density was inversely associated with several risk factors after adjustment for TAC volume. A significant improvement was observed over CAC when TAC volume and density were added into the risk prediction model. KEY POINTS: • Calcifications in the aorta can be non-invasively assessed using CT images • A higher calcium score is associated with a higher cardiovascular risk • Measuring the calcifications size and the density separately can improve the risk prediction.

Age-related changes of thoracic aorta geometry used to predict the risk for acute type B dissection.

AIMS: Risk models that use a single aortic diameter threshold have failed to successfully predict acute type B aortic dissection (TBAD). We sought to identify meaningful age-indexed anatomical variables to predict TBAD risk. METHODS AND RESULTS: A geometric deformable model, consisting of virtual elastic balloons that inflate inside a vessel lumen, was developed to quantify thoracic aorta geometry. In the presence of TBAD, true and total artery lumen morphology were assessed. A stepwise logistic model was built to predict TBAD risk. Initial covariates included age, gender, body mass index and all anatomic variables not directly related to the dissected segment. Patients with acute TBAD (n=34, 62±12years old, 57% male gender) were compared with subjects with symptoms of dissection, but with a subsequent negative diagnosis (n=51, 62±12years old, 76% male gender). Patient risk factors did not differ between groups. Most aortic anatomical variables were age-dependent. Aortic size was larger in every segment of the dissected with respect to non-dissected aortas (p<0.001). Variables entering the TBAD risk prediction model were aortic arch diameter, thoracic aorta length and age (predictability=0.9764, r=0.85), confirmed by a bootstrap internal validation. In dissected aortas, the true lumen volume was correlated to age (r=0.72). CONCLUSIONS: TBAD probability increases with a larger aortic arch diameter and a longer thoracic aorta, whereas threshold values increase with age. The aortic morphology was age-dependent. After dissection, true lumen volume correlated to age. The use of threshold values indexed to age should be encouraged to better prevent and eventually treat TBAD.

Asociación entre el calcio de la aorta torácica y la geometría de esta en una cohorte de sujetos asintomáticos con riesgo cardiovascular aumentado / Association between thoracic aorta calcium and thoracic aorta geometry in a cohort of asymptomatic participants at increased cardiovascular risk

Introducción y objetivos: La detección del calcio de la aorta torácica mejora la predicción del riesgo cardiovascular, en cuanto a los eventos cardiacos y no cardiacos, respecto a la obtenida solo con los factores de riesgo tradicionales. En este trabajo se ha investigado la influencia de la morfometría de la aorta torácica en la presencia y la magnitud de las calcificaciones aórticas. Métodos: Se realizaron exploraciones por tomografía computarizada cardiaca sin contraste en 970 participantes asintomáticos con riesgo cardiovascular aumentado. Se utilizó un algoritmo automático para estimar la geometría de toda la aorta torácica y se cuantificó la puntuación de Agatston del calcio aórtico. Se utilizó un modelo no paramétrico para analizar los percentiles de la puntuación de calcio según la edad. Se calcularon modelos de regresión logística para identificar asociaciones anatómicas con las concentraciones de calcio. Resultados: Las calcificaciones se concentraron en el cayado aórtico y la aorta descendente. Las mayores cantidades de calcio se asociaron con una aorta agrandada, desplegada, con menor estrechamiento y más tortuosa. El tamaño de la aorta ascendente no mostró correlación con la puntuación de calcio de la aorta, mientras que el tamaño de la aorta descendente es el parámetro que mostró mayor asociación: el riesgo de tener una puntuación de calcio global superior al percentil 90 fue 3,62 veces (intervalo de confianza, 2,30-5,91; p < 0,001) mayor por cada 2,5 mm de aumento del diámetro de la aorta descendente. La reducción gradual del diámetro, la tortuosidad, el despliegue y los volúmenes del cayado aórtico y la aorta descendente estaban correlacionados con mayor cantidad de calcio. Conclusiones: Las calcificaciones se hallaron predominantemente en el cayado aórtico y la aorta descendente y mostraron asociación positiva con el tamaño de la aorta descendente y el cayado aórtico, pero no con el tamaño de la aorta ascendente. Estas observaciones indican que la dilatación aórtica puede tener mecanismos diferentes y, por consiguiente, requiere estrategias preventivas distintas según el segmento considerado (AU)

Introduction and objectives: Thoracic aorta calcium detection is known to improve cardiovascular risk prediction for cardiac and noncardiac events beyond traditional risk factors. We investigated the influence of thoracic aorta morphometry on the presence and extent of aortic calcifications. Methods: Nonenhanced computed tomography heart scans were performed in 970 asymptomatic participants at increased cardiovascular risk. An automated algorithm estimated the geometry of the entire thoracic aorta and quantified the aortic calcium Agatston score. A nonparametric model was used to analyze the percentiles of calcium score by age. Logistic regression models were calculated to identify anatomical associations with calcium levels. Results: Calcifications were concentrated in the aortic arch and descending portions. Higher amounts of calcium were associated with an enlarged, unfolded, less tapered and more tortuous aorta. The size of the ascending aorta was not correlated with aortic calcium score, whereas enlargement of the descending aorta had the strongest association: the risk of having a global calcium score > 90th percentile was 3.62 times higher (confidence interval, 2.30-5.91; P < .001) for each 2.5-mm increase in descending aorta diameter. Vessel taper, tortuosity, unfolding and aortic arch and descending volumes were also correlated with higher amounts of calcium. Conclusions: Thoracic aorta calcium was predominantly found at the arch and descending aorta and was positively associated with the size of the descending aorta and the aortic arch, but not with the size of the ascending aorta. These findings suggest that aortic dilatation may have different mechanisms and may consequently require different preventive strategies according to the considered segments (AU)

Association Between Thoracic Aorta Calcium and Thoracic Aorta Geometry in a Cohort of Asymptomatic Participants at Increased Cardiovascular Risk.

INTRODUCTION AND OBJECTIVES: Thoracic aorta calcium detection is known to improve cardiovascular risk prediction for cardiac and noncardiac events beyond traditional risk factors. We investigated the influence of thoracic aorta morphometry on the presence and extent of aortic calcifications. METHODS: Nonenhanced computed tomography heart scans were performed in 970 asymptomatic participants at increased cardiovascular risk. An automated algorithm estimated the geometry of the entire thoracic aorta and quantified the aortic calcium Agatston score. A nonparametric model was used to analyze the percentiles of calcium score by age. Logistic regression models were calculated to identify anatomical associations with calcium levels. RESULTS: Calcifications were concentrated in the aortic arch and descending portions. Higher amounts of calcium were associated with an enlarged, unfolded, less tapered and more tortuous aorta. The size of the ascending aorta was not correlated with aortic calcium score, whereas enlargement of the descending aorta had the strongest association: the risk of having a global calcium score > 90th percentile was 3.62 times higher (confidence interval, 2.30-5.91; P < .001) for each 2.5-mm increase in descending aorta diameter. Vessel taper, tortuosity, unfolding and aortic arch and descending volumes were also correlated with higher amounts of calcium. CONCLUSIONS: Thoracic aorta calcium was predominantly found at the arch and descending aorta and was positively associated with the size of the descending aorta and the aortic arch, but not with the size of the ascending aorta. These findings suggest that aortic dilatation may have different mechanisms and may consequently require different preventive strategies according to the considered segments.

Association of thoracic aorta calcium and non cardiac vascular events in cardiac disease-free individuals.

OBJECTIVE: Thoracic aorta calcium (TAC) is measurable on the same computed tomography (CT) scan as coronary artery calcium (CAC) but has still unclear clinical value. We assessed TAC and CAC relations with non-cardiac vascular events history in a cohort of subjects at risk for cardiovascular disease. METHODS: We analyzed retrospectively 1000 consecutive subjects having undergone CAC detection by non-contrast multi-slice CT with measurement field longer than usual in order to measure total TAC including aortic arch calcium. We also determined partial TAC restricted to ascending and descending thoracic aorta sites by removing arch calcium from total TAC. Calcium deposits were measured with a custom made software using Agatston score. RESULTS: Compared with the rest of the cohort, the 30 subjects with non-cardiac vascular event history had higher median values [95% CI] of total TAC (282 [28-1809] vs 39 [0-333], p < 0.01) and partial TAC (4 [0-284] vs 0 [0-5], p < 0.01) but no different value of CAC (73 [0-284] vs 16 [0-148]). Odds ratio [95% CI] of having non-cardiac vascular event per 1-SD increase in log-transformed calcium value was significant for total TAC but not for CAC, if total TAC and CAC were entered separately (1.56 [1.12-2.24], p < 0.01 and 1.13 [0.86-1.50], respectively) or together (1.57 [1.10-2.32], p < 0.01 and 0.98 [0.73-1.32], respectively) in the logistic adjusted model. CONCLUSION: TAC assessment simultaneous with CAC detection provides complementary information on the extra coronary component of cardiovascular risk beyond CAC's coronary risk prediction. Further studies are required to prospectively confirm this result.

[Means and objectives of primary prevention in patients at high cardiovascular risk]. / Moyens et objectifs de la prévention primaire chez les patients à haut risque cardiovasculaire.

Since thirty years, cardiovascular mortality fell. That is linked, on the one hand, to an earlier and a more harsh care of the acute accident, and on the other hand, to development of the prophylactic treatment. But cardiovascular diseases stay the main cause of death in the most of western countries, in France in women, and in subjects over 65 years. That's why it is necessary to detect people with a high cardio-vascular risk before any complications so that they can be treated earlier and with an intensive mode. It relates to a global risk which is multifactorial, conducting to a treatment based on the evidence based medicine but also fitting to each patient and which requires his participation to the prevention. This is a 4P physical medicine: predictive, preventive, personalized and participative.

Impact of coronary artery calcium on cardiovascular risk categorization and lipid-lowering drug eligibility in asymptomatic hypercholesterolemic men.

BACKGROUND: Application of coronary artery calcium (CAC) for stratifying coronary heart disease (CHD) risk may change the proportion of subjects eligible for risk reduction treatment and decrease cost-effectiveness of primary prevention. We therefore aimed to analyze the impact of CAC on CHD risk categorization. METHODS: We measured CAC with electron beam computed tomography in 500 asymptomatic untreated hypercholesterolemic men and re-calibrated 10-year Framingham CHD risk by adding CAC score information (post CAC test risk) via an algorithm integrating relative risk and expected distribution of CAC in the population tested. Proportions of low (<10%), intermediate (10-20%) and high (>20%) risk categories, and of eligibility for lipid-lowering treatment, were compared between Framingham risk and post CAC test risk. RESULTS: In the overall population, post CAC test risk calculation changed risk categorization defined by Framingham assessment alone, with 10% more low risk and 10% less intermediate risk (p<0.01). Risk reclassifications were bidirectional since 30% of high and 30% of intermediate Framingham risk were downgraded to intermediate and low risk categories respectively, while 11% of low and 14% of intermediate Framingham risk were upgraded to intermediate and high-risk categories respectively. Post CAC test risk did not change the proportion of Framingham-based lipid-lowering treatment eligibility in the overall population but decreased it by 8% in intermediate Framingham risk subgroup (p<0.05). CONCLUSIONS: Addition of CAC to risk prediction resulted rather in downgrading than in upgrading risk and did not change treatment eligibility, except in intermediate risk subjects, less frequently eligible for treatment.

Early thoracic aorta enlargement in asymptomatic individuals at risk for cardiovascular disease: determinant factors and clinical implication.

OBJECTIVES: We analyzed, in above-average risk asymptomatic individuals, the factors determining early thoracic aorta enlargement. METHODS: Ascending aortic diameter (AAD) was measured with noncontrast multidetector computed tomography in 345 participants (mean age 56 years; 78% men) without cardiovascular disease. We analyzed the associations of AAD with risk factors and Framingham risk score (FRS), multidetector computed tomography-assessed coronary artery calcium (CAC), and ultrasound interrogation of plaque presence at five sites (right and left carotid arteries, right and left femoral arteries, and abdominal aorta), the number of diseased sites with presence of plaque being counted from 0 to 5. RESULTS: AAD was positively associated with age (P < 0.001), male sex (P < 0.01), body surface area (BSA; P < 0.001), hypertension (P < 0.001), systolic and diastolic blood pressures in individuals without antihypertensive medication (P < 0.05, P < 0.01), and FRS (P < 0.001). AAD was positively associated with CAC score after adjusting for age, sex, and BSA (P < 0001) or for FRS and BSA (P < 0.001). AAD was higher in the presence of three, four, or five than in the presence of no, one, or two diseased sites with plaque, after adjusting for age, sex, and BSA (P < 0.05) or for FRS and BSA (P < 0.001). When participants were divided into subsets by AAD tertiles and by number of sites with plaque, FRS and CAC score were greatest in individuals with AAD top tertile and 3-5 sites with plaque and lowest in those with AAD bottom tertile and 0-2 sites with plaque (P < 0.001). CONCLUSION: These findings suggest that thoracic ascending aorta dilatation is related to hypertension and represents a part of a generalized atherosclerotic process of the entire vasculature.