[Aneurysms of the ascending aorta and aortic arch]

Evaluation of the relationship between para-aortic adipose tissue and ascending aortic diameter using a new method

BACKGROUND

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 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 21 mm/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.

CONCLUSIONS

This is the first study which evaluated PAT measured by TTE. We found a significant association between PAT measured by TTE and ascending aorta width.

Reference values of thoracic aorta and pulmonary artery diameters by age and gender in healthy Chinese adults assessed by cardiac magnetic resonance imaging: data from national center for cardiovascular diseases of China

The aim of the study was to define normal ranges for thoracic aorta and pulmonary artery diameters relative to gender, age, body surface area (BSA) and body mass index (BMI) in healthy Chinese adults by cardiac magnetic resonance (CMR). We studied 200 healthy participants (100 men, 100 women; age range from 20-70) by using a 3.0-T CMR system. The diameters of the ascending aorta (AA), main pulmonary artery (PA), proximal descending aorta (DA) and Valsalva sinus (VAS) were measured manually by two experienced doctors on half-Fourier single-shot spin echo (HASTE) and balanced steady-state free precession (bSSFP) cine images. The mean value and age specific and gender adjusted normal limits were calculated. The linear regression analysis were performed between diameters and gender, age, BMI and BSA. The mean and 95% confidence interval(CI) of AA, PA, DA and VAS were 28.95 ± 4.61 mm(95% CI 19.92-37.99 mm), 22.41 ± 2.59 mm(95% CI 17.31-27.47 mm), 20.61 ± 2.96 mm(95% CI 14.81-26.42 mm), 31.15 ± 3.65 mm(95% CI 24.00-38.29 mm), respectively. The gender differences of all the parameters above were statistically significant (all p < 0.01). Both thoracic aorta and pulmonary artery dilates with the increase of age, while AA has the highest dilation rate. The mean PA/AA was 0.79 and showed no gender difference, but there was statistical difference among all age groups (p < 0.01). AA and DA had stronger association with age and BSA than BMI. Age- and gender-specific reference diameters of thoracic aorta and pulmonary artery were provided in healthy Chinese adults. Age and BSA have stronger effects on the ranges of diameters than BMI.

Wolfe procedure in a 78-year-old patient with aortic root aneurysm: A case report

BACKGROUND

Aortic root and ascending aortic aneurysms are traditionally surgically treated through the deployment of a conduit with an artificial aortic valve, which significantly increases the risk of postoperative complications in the form of thrombosis.

MATERIALS & METHODS

We report a case of Wolfe procedure in a 78-year-old female patient with aortic root aneurysm at high risk for conventional Bentall surgery.

DISCUSSION AND CONCLUSION

We use this case to discuss the effectiveness and short-term results of this procedure.

Patient-Specific CT-Based Fluid-Structure-Interaction Aorta Model to Quantify Mechanical Conditions for the Investigation of Ascending Aortic Dilation in TOF Patients

Background

Some adult patients with Tetralogy of Fallot (TOF) were found to simultaneously develop ascending aortic dilation. Severe aortic dilation would lead to several aortic diseases, including aortic aneurysm and dissection, which seriously affect patients' living quality and even cause patients' death. Current practice guidelines of aortic-dilation-related diseases mainly focus on aortic diameter, which has been found not always a good indicator. Therefore, it may be clinically useful to identify some other factors that can potentially better predict aortic response to dilation.

Methods

20 TOF patients scheduled for TOF repair surgery were recruited in this study and were divided into dilated and nondilated groups according to the Z scores of ascending aorta diameters. Patient-specific aortic CT images, pressure, and flow rates were used in the construction of computational biomechanical models.

Results

Simulation results demonstrated a good coincidence between numerical mean flow rate at inlet and the one obtained from color Doppler ultrasonography, which implied that computational models were able to simulate the movement of the aorta and blood inside accurately. Our results indicated that aortic stress can effectively differentiate patients of the dilated group from the ones of the nondilated group. Mean ascending aortic stress-P1 (maximal principal stress) from the dilated group was 54% higher than that from the nondilated group (97.97 kPa vs. 63.47 kPa, p value = 0.044) under systolic pressure. Velocity magnitude in the aorta and aortic wall displacement of the dilated group were also greater than those of the nondilated group with p value < 0.1.

Conclusion

Computational modeling and ascending aortic biomechanical factors may be used as a potential tool to identify and analyze aortic response to dilation. Large-scale clinical studies are needed to validate these preliminary findings.