Anatomical characteristics of the thoracic aortic arch in an Asian population

3D Characterization of the Aortic Valve and Aortic Arch in Bicuspid Aortic Valve Patients

Patients with bicuspid aortic valve (BAV) commonly have associated aortic stenosis and aortopathy. The geometry of the aortic arch and BAV is not well defined quantitatively, which makes clinical classifications subjective or reliant on limited 2D measurements. The goal of this study was to characterize the 3D geometry of the aortic arch and BAV using objective and quantitative techniques. Pre-TAVR computed tomography angiogram (CTA) in patients with BAV and aortic stenosis (AS) were analyzed (n = 59) by assessing valve commissural angle, presence of a fused region, percent of fusion, and calcium volume. The ascending aorta and aortic arch were reconstructed from patient-specific imaging segmentation to generate a centerline and calculate maximum curvature and maximum area change for the ascending aorta and the descending aorta. Aortic valve commissural angle signified a bimodal distribution suggesting tricuspid-like (≤ 150°, 52.5% of patients) and bicuspid-like (> 150°, 47.5%) morphologies. Tricuspid like was further classified by partial (10.2%) or full (42.4%) fusion, and bicuspid like was further classified into valves with fused region (27.1%) or no fused region (20.3%). Qualitatively, the aortic arch was found to have complex patient-specific variations in its 3D shape with some showing extreme diameter changes and kinks. Quantitatively, subgroups were established using maximum curvature threshold of 0.04 and maximum area change of 30% independently for the ascending and descending aorta. These findings provide insight into the geometric structure of the aortic valve and aortic arch in patients presenting with BAV and AS where 3D characterization allows for quantitative classification of these complex anatomic structures.

Certain aortic geometries and hemodynamics are associated with FID development and impact the evolution of uncomplicated type B intramural hematoma during the acute phase

OBJECTIVES

It is difficult to predict the evolution of uncomplicated type B intramural hematoma (IMHB) with a focal intimal disruption (FID) in the acute phase. The aims of this study were to investigate the predictors of FIDs and summarize the risk factors for the evolution of uncomplicated IMHB in the acute phase.

METHODS

Eighty-six patients with uncomplicated IMHB were included and were divided according to the development of an FID during the acute phase: the FID group (n = 32) and the no-FID group (n = 54). Geometric measurements and computed fluid dynamic calculations were based on a computed tomography scan performed on admission. Multivariate logistic regression analysis was used to estimate the predictors of FID development.

RESULTS

Thirty-two (37%) patients developed an FID. Patients with an FID had higher C-reactive protein levels (18.6 ± 2.3 vs 8.1 ± 0.2 mg/dL, P < 0.001) and white blood cell counts (10.3 ± 2.1 vs 7.5 ± 1.7 10⁹ /L, P < 0.001). The no-FID group had lower occurrences of disease progression (15% vs 64%, P < 0.001) and aorta-related mortality (6% vs 25%, P = 0.016). Multivariate logistic regression analysis indicated a significant risk for the occurrence of an FID with a larger maximum aortic diameter (OR, 1.35; 95% CI, 1.05-1.73, P = 0.020), thicker hematoma (OR, 2.20; 95% CI, 1.40-3.48, P = 0.001), and higher oscillatory shear index (per 0.01 unit, OR, 1.74; 95% CI, 1.21-2.49, P = 0.003). The aorta-related mortality during the acute phase was 25% (n = 8).

CONCLUSIONS

Certain aortic conditions, including ta larger aortic diameter, thicker hematoma and higher oscillatory shear stress, are associated with the FID development and result in worse clinical outcomes.

The endovascular repair of blunt traumatic thoracic aortic injury in Asia: A systematic review and meta-analysis

INTRODUCTION

Blunt traumatic thoracic aortic injury, the second leading cause of death from trauma, poses unique challenges in its management. However, there has not yet been a corresponding consolidated series of outcomes reported in Asia, which this systematic review aims to address.

METHOD

This review was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Searches were performed on MEDLINE, EMBASE, Google Scholar, and Cochrane Database for studies performed in Asia reporting the endovascular management of blunt traumatic thoracic aortic injury. Risk of bias was assessed using the Newcastle-Ottawa scale. Meta-analyses of pooled proportions were performed using the metaprop command in STATA. This review has been prospectively registered in PROSPERO (CRD42018083773).

RESULTS

Sixteen retrospective cohort studies were included, reporting a total of 238 patients. The pooled Injury Severity Score was 32.5 (95%CI 27.8-37.1). The pooled mean time to operation from diagnosis was 39.2 hours (95%CI 24.6-53.8 hours), and operation time was 100 min (95%CI 63.5-136.5 min). The pooled rate of procedural conversion from endovascular repair to open surgery was 0.17% (95%CI 0-3.7%), and the proportion of left subclavian artery coverage was 55% (95%CI 37-72%). The pooled prevalence of intra-operative all-cause and aortic-related mortality was 0.72% (95%CI 0-4.9%) and 0.27% (95%CI 0-3.8%), respectively. The pooled prevalence of 30-day all-cause and aortic-related mortality was 2.2% (95%CI 0.16-5.6%) and 2.1% (95%CI 0-3.7%), respectively. In terms of 30-day complication, the pooled prevalence rates of type 1 endoleak, endograft complications, vascular access injury, strokes, and aortic re-rupture were 1.2%, 0.34%, 0.14%, 0.02%, and 0.01%, respectively. There were no cases of types II and III endoleak, and renal failure.

CONCLUSION

Short- to mid-term results for thoracic endovascular aortic repair for blunt traumatic thoracic aortic injury in Asia are encouraging. However, there is a distinct disparity in reporting across Asia. We propose a prospective database for outcome reporting post thoracic endovascular aortic repair in this patient population, and ongoing follow up to assess long-term efficacy of this treatment strategy.

A simple patient-tailored aortic arch tangential angle measuring method to achieve better clinical results for thoracic endovascular repair of type B aortic dissection

Background

To report a simple individual tailored aortic arch tangential angle (θ-AATA) measuring method and its clinical application efficacy in the endovascular treatment of type B aortic dissection (AD).

Methods

From January 2013 to December 2014, acute type B AD patients were prospectively enrolled and treated with endovascular therapy in our center. Among these patients, a specific method was applied to measure θ-AATA based on the axial images of the CT scan. The length of proximal landing zone (PLZ) of each patient was measured at the routinely applied left-anterior oblique (LAO) 45-degree and θ-AATA. Respective treatment strategies based on the length of the PLZ were planned accordingly, and the stent-graft was deployed under the fluoroscopy at θ-AATA. The occurrence of immediate type I endoleak was recorded during the completion angiogram, while the alignment of the proximal marks was determined under fluoroscopy at θ-AATA and at LAO-45-degree as well.

Results

Totally 76 patients with type B AD were prospectively enrolled. The average value of θ-AATA was 58.3±5.2 degrees, which was significantly larger than the routine 45 degrees (P<0.01). The mean landing zone length measured under θ-AATA (18.4±3.9 mm) was longer than that (15.9±3.1 mm) obtained at the routine LAO-45 degrees (P<0.05). Stent-grafts' deployment strategies were substantially changed accordingly. Alignment of the proximal marks was achieved in 72 patients (93.4%) under θ-AATA and only in two patients (2.7%) at LAO-45 degrees (P<0.01). All stent-grafts' implantation was successfully completed. No major type I endoleak was found in the immediate post-deployment angiography.

Conclusions

It is easy to apply this patient-tailored θ-AATA measuring method in clinical practice. This more precise measurement is benefit for more reasonable treatment strategy planning, more precise deployment, and therefore a better outcome.

Design and Experimental Validation of an Active Catheter for Endovascular Navigation

Endovascular techniques have many advantages but rely strongly on operator skills and experience. Robotically steerable catheters have been developed but few are clinically available. We describe here the development of an active and efficient catheter based on shape memory alloys (SMA) actuators. We first established the specifications of our device considering anatomical constraints. We then present a new method for building active SMA-based catheters. The proposed method relies on the use of a core body made of three parallel metallic beams and integrates wire-shaped SMA actuators. The complete device is encapsulated into a standard 6F catheter for safety purposes. A trial-and-error campaign comparing 70 different prototypes was conducted to determine the best dimensions of the core structure and of the SMA actuators with respect to the imposed specifications. The final prototype was tested on a silicon-based arterial model and on a 23 kg pig. During these experiments, we were able to cannulate the supra-aortic trunks and the renal arteries with different angulations and without any complication. A second major contribution of this paper is the derivation of a reliable mathematical model for predicting the bending angle of our active catheters. We first use this model to state some general qualitative rules useful for an iterative dimensional optimization. We then perform a quantitative comparison between the actual and the predicted bending angles for a set of 13 different prototypes. The relative error is less than 20% for bending angles between 100 deg and 150 deg, which is the interval of interest for our applications.

CT patterns of acute type A aortic arch dissection: longer, higher, more anterior

OBJECTIVES

This study analysed CT patterns of the acute dissected aortic arch using original biometric features along with comparison with normal aortas.

METHODS

The diagnostic CT scans of 57 patients (42 males, age (mean ± SD: 64.5 ± 13.8 years) admitted with acute Stanford type A dissection involving the aortic arch were analysed by semi-automatic detection protocol of the true lumen of the dissection. We measured the distances from the apex to the ascending and descending aorta, the curvilinear length of the entire arch and of its segments (especially between the brachiocephalic artery trunk and the left subclavian artery), as well as the surface area, angle, height and shift of the arch. These measurements were compared with results previously obtained in a healthy cohort in an analysis adjusted for age, sex and weight. The surface area and rotation of the false lumen were also analysed.

RESULTS

Compared to normal aortic arches (N), dissected aortic arches (D) were longer (D: 155 ± 26  mm, N: 135 ± 25  mm, p = 0.002), higher (D: 51 ± 10  mm, N: 45 ± 9  mm, p = 0.04), and with a more anterior apex (shift: D: 1.19 ± 0.56, N: 1.40 ± 0.62, p = 0.007). False lumen occupied between 47-65% of the aorta, turned preferentially clockwise and its rotation decreased progressively along the arch.

CONCLUSIONS

The morphology of the dissected aortic arch differs from that of the normal arch. Thus, our compilation of aortic arch measurements may help improve existing endovascular devices and/or design of new endoprostheses. Advances in knowledge: In this article, we provide a comprehensive set of measurements of the dissected aortic arch, and show that dissected aortic arches are longer, higher, and with a more anterior apex than normal arches.

Traumatic aortic injury: does the anatomy of the aortic arch influence aortic trauma severity?

Purpose

Traumatic aortic injury (TAI) is a rare but life-threatening type of injury. We investigate whether the anatomy of the aortic arch influences the severity of aortic injury.

Methods

This is a retrospective study of twenty-two cases treated with TEVAR for TAI in our department from 2009 to 2014. Aortic injury was assessed in accordance with the recommendations of the Society of Vascular Surgery. We measured the aortic arch angle and the aortic arch index, based on the initial angio-CT scan, in each of the analyzed cases.

Results

The mean aortic arch index and mean aortic arch angle were 6.8 cm and 58.3°, respectively, in the type I injury group; 4.4 cm and 45.9° in the type III group; 3.3 cm and 37° in the type IV group. There were substantial differences in both the aortic arch index and the aortic arch angle of the type III and IV groups. A multivariate analysis confirmed that the aortic arch angle was significantly associated with the occurrence of type III damage (OR 1.5; 95% CI 1.03–2.2).

Conclusions

The severity of TAI is influenced by the sharpness of the aortic arch. There is an inverse relationship between the severity of aortic injury and the aortic arch index.

Synchronous hybrid repair for ruptured aneurysm of bovine aortic arch

Rupture of an aortic arch aneurysm is a life-threatening emergency with the risk of mortality escalating by the hour. We describe the successful hybrid repair of a ruptured bovine aortic arch aneurysm in a 75-year-old man, which involved aortic arch debranching by ascending aorta-bicarotid bypass followed by relining of the aortic lumen with a stent-graft. The procedure was not only lifesaving but also resulted in an active gentleman at 2-year follow-up. Considering the morbidity and mortality of open surgery using circulatory arrest, state-of-the-art synchronous hybrid repair seems to be an effective alternative for ruptured aortic arch aneurysms.

Hybrid Strategy for Residual Arch and Thoracic Aortic Dissection following Acute Type A Aortic Dissection Repair

Progressive dilatation of the false lumen in the arch and descending aorta has been encountered in one-third of survivors as a late sequelae following repair of ascending aortic dissection. Conventional treatment for the same requiring cardiopulmonary bypass and deep hypothermic circulatory arrest is associated with high morbidity and mortality especially in the elderly cohort of patients. Herein we report a case of symptomatic progressive aneurysmal dilatation of residual arch and descending thoracic aortic dissection following repair of type A aortic dissection, successfully treated by total arch debranching and ascending aortic prosthesis to bicarotid and left subclavian bypass followed by staged retrograde aortic stent-graft deployment. This case report with relevant review of the literature highlights this clinical entity and the present evidence on its appropriate management strategies. Close surveillance is mandatory following surgical repair of type A aortic dissection and hybrid endovascular procedures seem to be the most dependable modality for salvage of patients detected to have progression of residual arch dissection.