Sex-Specific Morphometric Analysis of Ascending Aorta and Aortic Arch for Planning Thoracic Endovascular Aortic Repair: A Retrospective Cohort Study.

OBJECTIVE: In many studies on aortic disease, women are underrepresented. The present study aims to assess sex-specific morphometric differences and gain more insight into endovascular treatment of the ascending aorta (AA) and arch. METHODS: Electrocardiogram-gated cardiac computed tomography scans of 116 consecutive patients who were evaluated for transcatheter aortic valve replacement were retrospectively reviewed. Measurements of the AA and aortic arch were made in multiplanar views, perpendicular to the semi-automatic centerline. Multiple linear regression analysis was performed to identify predictors affecting AA and aortic arch diameter in men and women. Propensity score matching was used to investigate whether sex influences aortic morphology. RESULTS: In both sexes, body surface area (BSA) was identified as a positive predictor and diabetes as a negative predictor for aortic diameters. In men, age was identified as a positive predictor and smoking as a negative predictor for aortic diameters. Propensity score matching identified 40 pairs. Systolic and diastolic mean diameters and AA length were significantly wider in men. On average, male aortas were 7.4% wider than female aortas, both in systole and diastole. CONCLUSIONS: The present analysis demonstrates that, in women, increased BSA is associated with increased aortic arch diameters, while diabetes is associated with decreased AA and arch diameters. In men, increased BSA and age are associated with increased AA and arch diameters, while smoking and diabetes are associated with decreased AA and arch diameters. Men were confirmed to have 7.4% greater AA and arch diameters than women. CLINICAL IMPACT: Men had 7.4% greater ascending aorta and arch diameters than women in a retrospective cohort, gated computed tomography-based study of 116 patients. Sex-specific differences in ascending aortic and arch size should be considered by aortic endovascular device manufacturers and physicians when developing ascending and arch endografts and planning aortic interventions.

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.

In the Fundamentals of Endovascular and Vascular Surgery model motion metrics reliably differentiate competency.

OBJECTIVE: The Fundamentals of Endovascular and Vascular Surgery, a curriculum that includes an endovascular model for skills testing, aims to differentiate between competent and noncompetent performers. The aim of our study was to further validate the model and to test its reliability in assessing the performance of endovascular trainees in an uncontrolled setting. METHODS: The model was tested exclusively in a virtual reality environment. On the basis of their endovascular experience, 52 participants were divided into three groups: novice (<50 endovascular cases), intermediate (50-500 endovascular cases), and expert (>500 endovascular cases). Performance was evaluated in four tasks, measuring the tool tip position and velocity on the virtual model. Average tool tip velocity and movement smoothness in the velocity frequency domain are validated parameters defining proficiency of movement. The data were filtered and interpolated to calculate the metrics. Trials containing critical tool manipulation errors were excluded. RESULTS: In total, 52 tasks completed by novices, 25 completed by intermediates, and 38 completed by experts were analyzed to determine performance. The difference in performance between the novice and expert groups was statistically significant for guidewire smoothness (P < .001). The expert group had a statistically significantly higher average guidewire velocity compared with the novice group (P < .001). CONCLUSIONS: The Fundamentals of Endovascular and Vascular Surgery model continues to differentiate novices from experts on the basis of their handling of guidewire and catheter tools, measured as smoothness and velocity. This model offers a useful instrument to test competency of endovascular surgeons.

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 < 30°, moderate 30°-60°, and high > 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.

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 (<30°), moderate (30°-60°) and high tortuosity (>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 Cardiac Cycle on Thoracic Aortic Geometry-Morphometric Analysis of Ecg Gated Computed Tomography.

BACKGROUND: Understanding morphological changes of ascending aorta, aortic arch and descending aorta with cardiac and respiratory motion is critical for planning of endovascular repair of thoracic aorta. The aim of this study was to determine the impact of the cardiac cycle on thoracic aortic geometry. METHODS: In this retrospective study, electrocardiogram-gated cardiac computed tomography from 116 patients who were evaluated for transcatheter aortic valve replacement were reviewed. A protocol for measurements of maximal diameters and lengths of the thoracic aorta and supra-aortic vessels was established. Measurements were made in multiplanar views perpendicular to the semiautomatically created centerline on both systolic and diastolic phases. RESULTS: Mean age was 77 ± 11 years of our study cohort. Mean systolic and diastolic diameter were 31.6 ± 0.42 and 30.1 ± 4.4 mm at the sinotubular junction (STJ), 35.6 ± 4.8 and 34.8 ± 4.7 mm in the ascending aorta, 29.1 ± 3.3 and 28.5 ± 3.3 mm in the aortic arch (distal left common carotid artery), and 26.7 ± 5.4 and 25.8 ± 5.4 mm in the descending aorta. Mean diameter change was 1.5 ± 0.9 mm at the STJ, 0.8 ± 0.9 mm in the ascending aorta, 0.6 ± 0.8 mm in the aortic arch, and 0.9 ± 1.2 mm in the descending aorta. Mean arterial strain was 5.0 ± 3.2% at the level of the STJ, 2.4 ± 2.7% in the ascending aorta, 2.0 ± 2.9% in the aortic arch, and 3.9 ± 5.7% in the descending aorta. CONCLUSIONS: Our results demonstrated that small but significant circumferential and longitudinal strain was present at every aortic level. These findings may have implications for endovascular thoracic aortic repair and may provide reference values for future comparison.

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

BACKGROUND: Aging 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 RESULTS: Two groups of hundred patients < 65 years and hundred patients ≥ 65 years, with no vascular diseases were made. Thin cut CT scans were analyzed with 3Mensio Vascular software and the following measurements were collected; tortuosity index, curvature ratio, maximum tortuosity in degrees and the level of vertebrae of the maximum tortuosity. The descending thoracic aorta (DTA) was analyzed and was divided into four zones of equal length. Subjects were divided into three groups based on their maximum tortuosity value: low (< 30°), moderate (30° - 60°) and high (> 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 < 65 group (tortuosity index: 1.05 vs. 1.14, respectively; p < 0.001), curvature ratio (1.00 vs. 1.01; p < 0.001), maximum tortuosity (22.24 vs. 27.26; p < 0.001), and group of angulation (low vs. low; p < 0.001). Additionally, the location of maximum tortuosity was further distal for the ≥ 65 group (level of vertebrae; 5.00 vs. 5.00; p < 0.001), and zone of maximum tortuosity (4A vs. 4A; p < 0.001). There was no significant difference between male and female subjects. CONCLUSION: Normal DTA tortuosity increases with age. This is important to understand natural aging and for TEVAR planning and follow-up.

Identifying and addressing the limitations of EVAR technology.

INTRODUCTION: Endovascular aortic repair (EVAR) has improved over the last two decades. Approximately 80% of the patients presenting with an abdominal aortic aneurysm (AAA) is nowadays primarily treated with EVAR. AREAS COVERED: In this review, the differences between endovascular and open repair, the clinical characteristics needed for EVAR, the role of clinical imaging and the developments in EVAR technology will be discussed. Early mortality is lower in EVAR as compared to open repair, whereas this benefit is lost after 3 years postoperatively. EVAR comes with a high reintervention rate, with endoleak being the most important predictive factor for reintervention. Expanding technical possibilities have allowed surgeons to choose from a palate of endovascular approaches in aneurysm patients with challenging anatomies. EXPERT COMMENTARY: Although EVAR has taken a giant leap forward in development, the new developments have seemed to surpass the long-term limitations with older devices. It is important to start focusing on the current limitations of EVAR, in particular the durability of devices in the human variable anatomic and dynamic environment.