Geometric, Biomechanic and Haemodynamic Aortic Abnormalities Assessed by 4D Flow Cardiovascular Magnetic Resonance in Patients Treated by TEVAR Following Blunt Traumatic Thoracic Aortic Injury

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) is widely used for the treatment of patients with blunt traumatic thoracic aortic injury (BTAI). However, aortic haemodynamic and biomechanical implications of this intervention are poorly investigated. This study aimed to assess whether patients treated by TEVAR following BTAI have thoracic aortic abnormalities in geometry, stiffness, and haemodynamics.

METHODS

Patients with BTAI treated by TEVAR at Vall d'Hebron Hospital between 1999 and 2019 were compared with propensity score matched healthy volunteers (HVs). All subjects underwent cardiovascular magnetic resonance (CMR) comprising a 4D flow CMR sequence. Spatially resolved aortic diameter, length, volume, and curvature were assessed. Pulse wave velocity, distensibility, and longitudinal strain (all measurements of aortic stiffness) were determined regionally. Moreover, advanced haemodynamic descriptors were quantified: systolic flow reversal ratio (SFRR), quantifying backward flow during systole, and in plane rotational flow (IRF), measuring in plane strength of helical flow.

RESULTS

Twenty-six BTAI patients treated by TEVAR were included and matched with 26 HVs. They did not differ in terms of age, sex, and body surface area. Patients with TEVAR had a larger and longer ascending aorta (AAo) and marked abnormalities in local curvature. Aortic stiffness was greater in the aortic segments proximal and distal to TEVAR compared with controls. Moreover, TEVAR patients presented strongly altered flow dynamics compared with controls: a reduced IRF from the distal AAo to the proximal descending aorta and an increased SFRR in the whole thoracic aorta. These differences persisted adjusting for cardiovascular risk factors and were independent of time elapsed since TEVAR implantation.

CONCLUSION

At long term follow up, previously healthy patients who underwent TEVAR implantation following BTAI had increased diameter, length and volume of the ascending aorta, and increased aortic stiffness and abnormal flow patterns in the whole thoracic aorta compared with matched controls. Further studies should address whether these alterations have clinical implications.

Aortic Neck Dilatation Following Thoracic Endovascular Aortic Repair

OBJECTIVE

Thoracic endovascular aortic repair (TEVAR) has become a mainstay of treatment for a variety of thoracic aortic pathologies. Expansion of the proximal aortic neck after endovascular repair of abdominal aortic aneurysms has been demonstrated; however, dilatation of the proximal aortic neck after TEVAR has not been well described. We sought to describe remodeling of the proximal neck following TEVAR.

METHODS

This is a retrospective, single institution review of patients who underwent TEVAR for thoracic aortic aneurysm (TAA) and dissection with aneurysmal degeneration from 2010 to 2019. Postoperative computed tomography scans were reviewed and aortic diameter was measured in orthogonal planes using 3-dimensional centerline reconstruction software. The primary outcome was change in aortic diameter at the proximal aortic neck as compared to the initial postoperative computed tomography scan. Clinical and operative data were analyzed to identify factors associated with significant neck dilatation.

RESULTS

Of 87 patients who underwent TEVAR during the study period, 30 met inclusion criteria. Median follow up was 20.5 months. Median age was 67 years, and 15 patients (50%) were female. The proximal aortic neck experienced an overall increase over time in aortic diameter. Five mm distal to the graft showed the greatest rate of expansion, with a median increase of 1.3, 2.9, and 6.2 mm at one year, two years, and three years, respectively. When comparing patients who had mean expansion at this location of >2.0 mm/year to patients who did not, a higher percentage had dissection pathology (81.8% vs. 31.6%, P = 0.008), had graft placement at aortic landing zone 2 (36.4% vs. 5.3%, P = 0.028), and were smokers (100% vs. 52.6%, P = 0.006). Higher percent oversizing was shown to be associated with significant aortic neck dilatation for true aneurysms only.

CONCLUSIONS

Aortic neck dilatation occurs over time for the majority of patients following TEVAR with the distal neck experiencing the highest rate of expansion. Dissection pathology, aortic landing zone 2, and smoking were found to be associated with a higher rate of neck dilatation.

Endovascular repair of traumatic aortic isthmic rupture: Early and mid-term results

INTRODUCTION

Conventional open repair of a traumatic aortic isthmic rupture is associated with a significantly high mortality and morbidity rates. Thoracic endovascular aortic repair (TEVAR) is currently often performed because it is a less invasive treatment than surgery. The aim of this study was to evaluate short and mid-term results of TEVAR in traumatic aortic isthmic rupture.

METHODS

This is a retrospective study conducted between 2010 and 2018 including patients who underwent TEVAR for traumatic aortic isthmic rupture.

RESULTS

Thirty-six consecutive patients were included. All patients had sustained a violent blunt chest trauma after a sudden deceleration with associated injuries. The injury severity score (ISS) was 40 (14-66). All patients were hemodynamically stable at admission. We deployed thoracic aorta stent grafts with a mean diameter of 26mm (18-36). The procedural success rate was 100%. We reported one intra-operative complication which was a distal migration of the graft, managed by an implantation of an aortic extension graft. On the first postoperative day, one patient presented an acute lower limb ischemia, probably due to the surgical femoral access, treated with an embolectomy with a Fogarty catheter with satisfactory results. The mean follow-up was 40.41 months (6.5-96). The mortality and paraplegia rates were 0% at one month and during the follow-up period. We reported a case of kinking of the graft that occurred at 6 months. No cases of endoleak neither re-intervention were reported.

CONCLUSION

TEVAR is a safe and a reliable method for the treatment of sub-acute traumatic thoracic aortic injuries.

Thoracic Aortic Dilation after Endovascular Repair of Blunt Traumatic Aortic Injury

BACKGROUND

Thoracic endovascular aneurysm repair (TEVAR) has become the current standard of care for emergent treatment of traumatic blunt thoracic aortic injuries (BTAI). Although aortic dilation (AD) of the infrarenal neck after EVAR for aortic aneurysms has been studied, changes in aortic diameter after TEVAR for BTAI is not well understood. This study aims to characterize changes in thoracic aortic diameter after stent-graft placement in the setting of nonaneurysmal traumatic aortic injury.

METHODS

A single-center, retrospective review was performed involving patients presenting with BTAI treated with TEVAR. Only patients with at least 12 months follow-up were included. Aortic diameter, defined as the outer-to-outer diameter on 3D center-line imaging, was measured at six locations along the proximal and mid thoracic aorta. The first postoperative CT (≤1 month) served as a baseline from which interval measurements were compared.

RESULTS

Twenty patients with BTAI treated from 2011 to 2017 had adequate imaging available for review and were included in this study cohort. Median follow-up time was 46.8 (12-80, range) months. At the latest follow-up, AD occurred at all measured locations within the endograft, starting from the proximal graft edge (0.62 ± 0.69 mm, P = 0.027) to the distal graft edge (1.21 ± 1.28 mm, P = 0.003). AD was most pronounced in the distal graft segment 2 cm proximal to the distal graft edge, with a mean AD of 1.32 ± 1.59 mm (+5.3%, P < 0.001). At this location, AD was found to increase in a linear manner with an estimated rate of 0.67 ± 0.20 mm/year (P = 0.006). The native aorta proximal and distal to the endograft was not found to significantly dilate during follow-up (P = 0.280-0.897). Seventy percent of the patients were found to have AD >5%. The amount of AD was not found to be associated with either graft oversizing (P = 0.151) or age (P = 0.340). There were no cases of graft migration, erosion, or endoleak.

CONCLUSIONS

AD is a common benign finding after TEVAR for BTAI. AD is most pronounced at the near the distal end of the stent graft. In late-term follow-up, there are no known associated complications related to AD.

Impact of the Bird-Beak Configuration on Postoperative Outcome After Thoracic Endovascular Aortic Repair: A Meta-analysis

Purpose: To investigate the association between the bird-beak configuration (BBC), a wedge-shaped gap between the undersurface of a thoracic endograft and the lesser curvature of the arch after thoracic endovascular aortic repair (TEVAR), and postoperative outcome after TEVAR. Methods: The study was performed according to the PRISMA guidelines. The PubMed, EMBASE, and Cochrane databases were searched to identify all case series reporting BBC after TEVAR between 2006 and April 2018. Data analysis was performed considering the difference in the risk of complications for presence vs absence of BBC. After screening 1633 articles, 21 studies were identified that matched the selection criteria; 12 of these reported detailed information to investigate the postoperative outcome using proportion meta-analysis with a random effects model. The pooled risk difference is reported with the 95% confidence interval (CI). Heterogeneity of the included studies was assessed with the I2 statistic (low 25%, medium 50%, high 75%). Results: Complications occurred within a range of 0 to 72 months in 14.7% (95% CI 7.4% to 27.3%) of patients with BBC and in 6.3% (95% CI 2.5% to 15.4%) of patients without BBC. A cumulative incidence could not be assessed. The summary risk difference was 11.1% (95% CI −0.1% to 22.3%, p=0.052). There was significant heterogeneity ( I2=85.6%). The Egger test did not show evidence of publication bias (p=0.975). When specifically considering type Ia endoleak and endograft migration, the risk difference between BBC and non-BBC patients was 8.2% (95% CI 0.3% to 16.1%, p=0.042; I2=69.0%). The specific risk difference for endograft collapse/infolding and thrombosis was 3.7% (95% CI −3.5% to 11.1%, p=0.308; I2=10.2%). Conclusion: At present the literature does not provide statistical evidence to establish an overall prognostic value of the BBC. Nevertheless, the BBC appears to be associated with a high risk of type Ia endoleak and endograft migration, which warrants specific and long-term surveillance. Clinically relevant values for BBC grading should be established to perhaps define indications for preemptive treatment based on the presence of BBC only.

The effect of TEVAR for blunt traumatic thoracic aortic injury on maximal aortic diameter: Mid- and long-term outcome

Objective

Thoracic endovascular aortic repair (TEVAR) has become the standard of care for blunt thoracic aortic injury (BTAI). Long-term effects of TEVAR on the aortic diameter are not well studied. This study evaluates the effect of TEVAR for BTAI on the aortic diameter in mid- and long-term follow-up.

Methods

All patients treated with TEVAR for BTAI between August 2000 and May 2016 were included. Maximum aortic diameter was measured at four predetermined thoracic aortic levels in the preoperative and first postoperative CT angiography (CTa) and in the last control CTa or MR angiography: 1 cm proximal (D1) and 1 cm distal to the left subclavian artery (D2), 3 cm distal to the left subclavian artery (D3) and 3 cm proximal to the celiac trunk (D4).

Results

A total of 27 patients (20 men, mean age 40 years (±17.55) were included. Mean follow-up time was 90 months (±48.36)). No re-interventions were needed. Mean growth of aortic diameter at level D1, D2, D3 and D4 was 0.22 mm ± 3.66, 1.79 mm ± 3.82, 0.73 mm ± 4.18 and –1.06 mm ± 2.82, respectively, when comparing last follow-up to the preoperative imaging without any statistical significant differences. When comparing the preoperative diameter with the first postoperative CT, only a statistical significant growth of 2.81 mm ± 2.69 was seen at level of D2 ( p < 0.05)

Conclusion

During mid- to long-term follow-up, a temporary significant increase of the maximum aortic diameter was seen at level D2 in the direct postoperative phase This increase was not associated with clinical events and suggests long-term efficacy of TEVAR after BTAI.

Endovascular management of penetrating and non-penetrating aortic injury

Aortic trauma is a devastating injury often associated with significant polytrauma. Penetrating injury of the aorta is highly lethal and therefore rarely encountered in the hospital setting. The management of blunt trauma of the aorta has changed significantly over the past decade, principally due to improved imaging technology and the development of endovascular therapy. The most common site of injury is the proximal descending thoracic aorta. The degree of aortic wall injury guides the indication for therapy, while a combination of the degree of injury and the extent of co-morbid injuries drives the timing of repair. Lower grade injuries frequently do not require any surgical intervention. Thoracic aortic endograft repair can be performed in a safe, expeditious fashion. Short-term and mid-term outcomes appear excellent, with patient survival based mainly on concomitant traumatic injuries. Long-term outcomes are less well known. Future endeavors will be guided toward gaining a better understanding of the indications for repair and the long-term outcomes for endograft devices designed for this purpose.