Important longitudinal and circumferential pulsatile changes in zone 0 of the aorta during the cardiac cycle

Objectives: Correct stent-graft sizing is important when planning for thoracic endovascular repair in zone 0. As the movements of the aorta are constantly evolving in longitudinal and circumferential directions during the cardiac cycle, the diameter may not be the only important measurement. The aim of this study is to measure the circumferential and longitudinal pulsatile changes throughout the cardiac cycle. Methods: Ninety-two patients, who were evaluated for transcatheter aortic valve replacement, were selected for this retrospective study. Their electrocardiogram-gated cardiac computed tomography was analysed. We identified the area, perimeter and diameter of the thoracic aorta in zone 0 and calculated the differences between these parameters at 3 locations in zone 0. The measurements were made in multiplanar views perpendicular to the semi-automatically created centreline in both systolic and diastolic phases. Results: The mean age of our study cohort was 77 ± 11 years. The mean change between systole and diastole of the area (mm2), perimeter (mm) and diameter (mm) were compared at 3 different locations in the ascending aorta: at the sinotubular junction (0.78 mm2 vs 0.89 mm vs 1.41 mm), mid-ascending (0.72 mm2 vs 0.68 vs 0.81 mm) and proximal edge of the brachiocephalic artery (0.76 mm2 vs 0.73 mm vs 0.73 mm). The change in percentage is the smallest in the area at the sinotubular junction compared to the perimeter and diameter (2.6% vs 3.1% vs 4.7%). Conclusions: Changes in measurement of ascending aortic diameter with cardiac cycle are larger than measurement change in the area. This is especially more pronounced in zone 0A. For more accurate information on the morphometric changes, it may be necessary to measure the area when planning for thoracic endovascular repair to maximize results. A prospective study comparing these different measurements regarding the outcomes is advised by the authors to understand the clinical implications

Computational Fluid Dynamics in Descending Thoracic Aortic Aneurysm: Tortuosity Associated With High Displacement Forces

Tortuosity comes with higher displacement forces in the aorta. As the descending thoracic aorta (DTA) is becoming longer and more tortuous with age, it is important to understand the influence of tortuosity on displacement forces in the DTA

Tortuosity of the descending thoracic aorta: Normal values by age.

BackgroundAging changes the aorta in length, tortuosity and diameter. This is relevant in thoracic endovascular aortic repair (TEVAR) and in the long term follow up.Methods and resultsTwo groups of hundred patients 60°). A linear regression model was built to test the effect of age and gender on tortuosity. Tortuosity was more pronounced in the ≥ 65 compared to the ConclusionNormal DTA tortuosity increases with age. This is important to understand natural aging and for TEVAR planning and follow-up

Type 1b Endoleaks After Thoracic Endovascular Aortic Repair are Inadequately Reported: A Systematic Review

Background: Complications after thoracic endovascular aortic repair (TEVAR) are common. Even after a successful TEVAR, a late endoleak (>30 days) can occur. The objective of this study is to summarize the current evidence and, if lacking, the need of evidence regarding the incidence and predictive factors for type 1b endoleak in patients with aortic aneurysm treated with TEVAR. Methods: A systematic review of the literature was performed on endoleak type 1b, in patients with aortic aneurysm, after TEVAR. The PubMed and Embase databases were systematically searched for articles regarding endoleak type 1b up to January 2019. The main subjects discussed are the incidence, risk factors, treatment, and prognosis. Results: About 722 articles were screened, and 16 articles were included in this review. The reported incidence of endoleak is between 1.0% and 15.0%, with a mean follow-up duration of at least 1 year. Type 1b endoleak is associated with an increased aortic tortuosity index (>0.15 cm−1). No significant difference is found in relation to age and gender. Treatment is required in most cases (22/27) and is usually performed with distal extension of the stent graft (21/27). There are no data regarding stent graft oversizing, length of distal landing zone, and differences between devices or the prognosis for patients with type 1b endoleak. Conclusions: Limited literature is available on the occurrence of type 1b endoleak after TEVAR. A tortuous aorta can be associated as a predictive factor for the occurrence of type 1b endoleak. Data clearly delineating the anatomic variables predicting type 1b endoleak should be examined and listed. Likewise, the impact of more recent conformable devices to prevent complications like type 1b endoleaks from occurring should be elucidated

Tortuosity of the Descending Thoracic Aorta in Patients with Aneurysm and Type B Dissection

Objective: Tortuosity in the descending thoracic aorta (DTA) comes with aging and increases the risk of endoleaks after TEVAR. With this report, we would like to define and classify tortuosity in the DTA of patients with thoracic aortic disease. Methods: Retrospective case–control study of two hundred seven patients, comparing sixty-nine controls without aortic disease (CG), to sixty-nine patients with descending thoracic aortic aneurysm (AG) and sixty-nine patients with type B aortic dissection (DG). 3Mensio Vascular software was used to analyze CTA scans and collect the following measurements; tortuosity index, curvature ratio and the maximum tortuosity of the DTA. The DTA was divided into four equal zones. The maximum tortuosity was divided into three groups: low (60°). Results: Compared to the CG, tortuosity was more pronounced in the DG, and even more in the AG, evidenced by the tortuosity index (1.11 vs. 1.20 vs. 1.31; p < 0.001), curvature ratio (1.00 vs. 1.01 vs. 1.03; p < 0.001), maximum tortuosity in degrees (28.17 vs. 33.29 vs. 43.83; p < 0.001) and group of tortuosity (p < 0.001). The maximum tortuosity was further distal for the DG and AG, evidenced by the zone of maximum tortuosity (4A vs. 4B vs. 4B; p < 0.001). Conclusion: This study shows that tortuosity in the DTA is more prominent in diseased aortas, especially in aneurysmal disease. This phenomenon needs to be taken into account during planning of TEVAR to prevent stent graft-related complications and to obtain positive long-term outcome

Impact of Aortic Tortuosity on Displacement Forces in Descending Thoracic Aortic Aneurysms

Objective: As elastin fibres in the aorta deteriorate with age, the descending thoracic aorta (DTA) becomes longer and more tortuous. In patients with DTA aneurysms, this increased tortuosity may result in a hostile haemodynamic environment for thoracic endovascular aortic repair (TEVAR). The objective of this study was to analyse how increased tortuosity affects haemodynamic displacement forces (DFs) in different segments of the DTA in patients with DTA aneurysms (DTAAs). Methods: Thirty patients with DTAAs were selected to form three equal groups based on the maximum tortuosity of their DTA: low 60°. Computational fluid dynamics simulations were performed to calculate DFs in all patients. Image based segmentations were carried out to create patient specific models of the aortic geometry. When physiological simulation results were obtained, the haemodynamic DFs on the aortic wall were calculated in four segments of the DTA (zones 4A – D). To enable comparison of DFs in different segments, the DF was normalised by the aortic wall surface area, the equivalent surface traction (EST). Results: The mean age was 73 years, with 67% male. In zone 4C, where most tortuosity occurs, the EST in patients with high tortuosity was more than three times higher, than those with low tortuosity (low, 743 N/m2; moderate, 956 N/m2; high, 2294 N/m2; p = .004). These differences could be attributed to the higher sideways components of the DF vectors, which were more than two times greater in patients with high tortuosity than in patients with low or moderate tortuosity (low, 5.01 N; moderate, 5.50 N; high, 13.21 N; p = .009). Conclusion: High tortuosity results in increased displacement forces in the distal segments of the DTA. These forces should be taken into account when planning for TEVAR, as potentially they increase the risk of stent graft related complications, such as migration and endoleak