Evaluation of the Relationship between Para-aortic Adipose Tissue and Ascending Aortic Diameter using a New Method

Purpose: Para-aortic adipose tissue (PAT) is the local adipose tissue that externally surrounds the aorta. It contributes significantly to aortic atherosclerosis and enlargement. Studies conducted with computed tomography and magnetic resonance have shown that individuals with aortic aneurysm had more PAT than healthy individuals. In this study, we measured PAT for the first time using transthoracic echocardiography (TTE).The aim of this study is to investigate the possible relationship of TTE measured PAT with ascending aortic width.Methods: PAT was defined as the hypoechoic space in front of ascending aortic 2 cm above the sinotubular junction at the end of the systole. Patients were divided into 2 groups according to the presence of dilatation in the ascending aorta using Roman's classification (aortic size index, ASI). ASI of less than 21 was considered no aortic dilation and an ASI of 21mm/m2 or greater was considered to have aortic dilation.Results: A total of 321 unselected patients were divided into the ascending aortic dilatation (AAD) group (n=96) and the normal ascending aorta diameter group (n=225 patients). PAT was significantly higher in the AAD group compared with the non-ADD group (0.9 (0.48) vs. 0.7 (0.91) mm, p < 0.0001). Univariate and multivariate logistic regression analysis revealed that PAT (OR: 3.005, 95%CI (1.445–6.251)) were significantly associated with AAD.Conclusion: Our results showed an association between PAT measured by transthoracic echocardiography and ascending aorta width. PAT appears to be an important follow-up parameter in patients at risk of developing aortic aneurysm.

Investigation of the correlation between cardiac parameters and aortic diameter in patients with ascending aortic aneurysm

Background Aortic aneurysms (AA) are enlargement of the aorta silently until diagnosing, not detectable on physical examination, and usually incidentally discovered during radiologic scanning for other reasons. It can get bigger sizes and can result in life-threatening outcomes if not detected early on. In this study, we aimed to determine the relationship between ascending aortic diameter and cardiac parameters that can be detected with tomography or/and echocardiography. Newly diagnosed (n: 85) ascending AA patients and healthy individuals (n: 86) who have not any thoracic pathology in computed tomography (CT) scans included to the study. Echocardiographically determined left atrial dimension (LAD), left ventricular end-diastolic diameter (LVDd), left ventricular end-systolic diameter (LVDs), left ventricular ejection fraction (LVEF) and the left ventricular posterior wall thickness (LVPWd) values of each patient were recorded. The thorax diameters, ascending aorta diameters and cardiac volume values recorded from CT scans. The obtained findings were statistically compared. Results Positive correlation was found between aortic diameter and aging (p: 0.000). Increased thorax diameter and cardiac volume values were detected in ascending AA cases (p < 0.05). It was found to be ascending aortic diameter was positively correlated with thorax diameter and cardiac volume (0.50 < r ≤ 0.70) values and higher aortic diameter, cardiac volume, thorax diameter values were detected in male individuals when compared with the female gender. There was no significant correlation between LVEF, LVDd, and LVDs values and aortic diameter. Conclusions Cardiac volume and thorax diameter were found as strongly correlated with the diameter of the ascending aorta. The clarifying of these parameters with larger cohorts might be beneficial for the estimation of the progression of ascending AA.

Pregnancy in women with bicuspid aortic valve

Background Aortic dissection during pregnancy is uncommon, however, the risk of aortic dissection is increased if there is underlying aortopathy. Bicuspid aortic valve (BAV) is common in the general population and is associated with the presence of an aortic aneurysm, but this condition is mostly asymptomatic and ignored in women of childbearing age. Data on pregnancy in patients with BAV are scarce, and guidelines on this topic are based on the consensus opinion of experts. The risk of occurrence of aortic dissection as a function of aortic diameter during pregnancy remains poorly known in women with BAV. Purpose To investigate demographic and echocardiographic characteristics and aortic events associated with pregnancy in women with BAV and to estimate ascending aortic diameter at the time of pregnancy. Methods We performed a retrospective study using data from our tertiary centre. All women seen at our centre between 1996 and 2020 with BAV, at least 1 pregnancy, and no genetic syndrome were included. We have collected data from echocardiograms performed in and out of our centre and aortic events. Assuming from the literature an annual aortic dilation rate of 0.2 mm at the sinus of Valsalva and 0.4 mm at the tubular ascending aorta, we estimated ascending aortic size and Z-score at the time of pregnancy. Results We identified 47 women with BAV with occurrence of 103 pregnancies. The median age of BAV diagnosis was 43 years. The aorta was measured at a median of 13.3 years since the last delivery. At BAV diagnosis, the median largest ascending aortic diameter was 44mm, and the median Z-score was +4.3. Ascending aortic diameter was ≥40mm in 37/47 (79%) and Z-score ≥2 in 44/47 (94%). No aortic dissection was observed during pregnancy and postpartum in all 103 pregnancies. At the time of pregnancy, the estimated median diameter of the ascending aorta was 37mm and the estimated median Z-score was +3.3. The largest aortic diameter during pregnancy was estimated to be ≥40mm in 36/103 pregnancies, ≥45mm in 13/103, and ≥50mm in 1/103; Z-score was estimated to be ≥2 in 81/103 and ≥4 in 40/103. Type A aortic dissection occurred in 1 woman, 13 years after pregnancy, and type B aortic dissection in 1 woman, 14 years after pregnancy. Planned surgery was performed in 8 women at a median of 17.5 years after the last pregnancy: 1 isolated aortic valve replacement and 7 prophylactic aortic surgeries associated with aortic valve surgery. Conclusions In our population of women with BAV, pregnancy is not associated with the occurrence of aortic dissection even though, when estimating aortic diameter at the time of pregnancy, the rate of aortic dilation was high (Z-score ≥2 in 81/103 pregnancies). Prospective studies of a large population of women with BAV are needed to assess the risk of aortic complication during pregnancy according to aortic diameter. FUNDunding Acknowledgement Type of funding sources: None.

Hemodynamic Environment Characteristics in the Ascending Aorta After Dilation Formed for the Bicuspid Aortic Valve Patients

Background: The bicuspid aortic valve is one of the common congenital heart anomalies in adults. Although many studies have proved the coincidence between bicuspid aortic valve and the occurrence of ascending aortic dilation, seldom study has focused on the hemodynamic environments after the dilation already formed. Four numerical models of bicuspid aortic valve were constructed in this study, based on medical images, with different ascending aortic dilation levels. The diameters of ascending aortic are 3.5cm, 4.0cm, 4.5cm and 5.0cm, respectively; while, the size and the geometry of other parts are fixed. Then hemodynamics in these models was simulated numerically and the flow patterns and loading distributions were investigated. Aim of this study is to investigate the hemodynamic environment characteristics in the ascending aorta after dilation formed for the bicuspid aortic valve (BAV) patients. Results: Hemodynamics environments in the dilated ascending aorta were simulated, with different level of dilation. As the diameter increases, the blood flow becomes more disturbing. The wall shear stress at the ascending aortic decreases while oscillatory shear index increases with the increase of diameter. The pressure at ascending aortic increases as the diameter increases. Moreover, all these hemodynamic parameters described above are asymmetrically distributed with the increase of ascending aortic diameter and more parts of aorta would be affected with the increasing ascending aorta diametersConclusions: The study revealed that the ascending aortic dilation levels can significantly influence the magnificent and distribution of the dynamics. There are altered flow patterns, pressure difference, WSS and OSI distribution features in bicuspid aortic valve patients with valvular dilation. As the extent of aortic dilatation increases, more parts of aorta like aortic arch should be paid more attention to when an individual is referred for surgery

High heritability of ascending aortic diameter and multi-ethnic prediction of thoracic aortic disease.

Enlargement of the aorta is an important risk factor for aortic aneurysm and dissection, a leading cause of morbidity in the developed world. While Mendelian genetics account for a portion of thoracic aortic disease, the contribution of common variation is not known. Using standard techniques in computer vision, we performed automated extraction of Ascending Aortic Diameter (AsAoD) from cardiac MRI of 36,021 individuals from the UK Biobank. A multi-ethnic genome wide association study and trans-ethnic meta-analysis identified 99 lead variants across 71 loci including genes related to cardiovascular development (HAND2, TBX20) and Mendelian forms of thoracic aortic disease (ELN, FBN1). A polygenic risk score predicted prevalent risk of thoracic aortic aneurysm within the UK Biobank (OR 1.50 per standard deviation (SD) polygenic risk score (PRS), p=6.30x10-03) which was validated across three additional biobanks including FinnGen, the Penn Medicine Biobank, and the Million Veterans Program (MVP) in individuals of European descent (OR 1.37 [1.31 - 1.43] per SD PRS), individuals of Hispanic descent (OR 1.40 [1.16 - 1.69] per SD PRS, p=5.6x10-04), and individuals of African American descent (OR 1.08 [1.00 - 1.18] per SD PRS, p=0.05). Within individuals of European descent who carried a diagnosis of thoracic aneurysm, the PRS was specifically predictive of the need for surgical intervention (OR 1.57 [1.15 - 2.15] per SD PRS, p=4.45x10-03). Using Mendelian Randomization our data highlight the primary causal role of blood pressure in reducing dilation of the thoracic aorta. Overall our findings link normal anatomic variation to extremes observed in Mendelian syndromes and provide a roadmap for the use of genetic determinants of human anatomy in both understanding cardiovascular development while simultaneously improving prediction and prevention of human disease.