Bovine Aortic Arch: Predictor of Entry Site and Risk Factor for Neurologic Injury in Acute Type A Dissection

Morphological characteristics and outcomes of aortic repair of acute type A aortic dissection occurring in patients with aortic arch branching variants

PURPOSE

To investigate the morphological characteristics and operative outcomes of acute type A aortic dissection (ATAAD) in patients with aortic arch variants.

METHODS

Of 616 patients with ATAAD, 97 (15.7%) had aortic arch variants, including bovine aortic arch (BAA, n = 66), isolated left vertebral artery (ILVA, n = 25), and aberrant subclavian artery (ASA, n = 6). The characteristics and outcomes were compared between the normal branching group (control, n = 519) and the total/individual arch variant groups.

RESULTS

Compared to the control group, arch entry was more prevalent in the BAA (18.5% vs. 31.8%) and ILVA groups (44%) (both, P < 0.05), and right common carotid arterial occlusion was less common in the arch variant group (6.7% vs. 0%, P = 0.017). The in-hospital mortality (9.2% vs. 9.3%), new-onset stroke (7.3% vs. 7.2%), and 5-year survival (81.7% vs. 78.8%) did not differ markedly between the control and arch variant groups. Arch repair was performed in 28.9% (28/97) of the arch variant group using 3-4 vessel antegrade cerebral perfusion, with 3.8% in-hospital mortality and a 15.4% stroke rate, which were comparable to those of the control group.

CONCLUSIONS

Aortic arch variants may influence tear location and involvement of the supra-arch vessels but may not affect postoperative outcomes.

Medical-Surgical Implications of Branching Variation of Human Aortic Arch Known as Bovine Aortic Arch (BAA)

(1) Background: The aortic arch (AA) branching model is challenging, considering the multiple anatomical variations documented in existing research. The bovine aortic arch (BAA) is the most prevalent anatomical variation among these. This variant of AA branching has long been considered a nonsymptomatic malformation, having been discovered incidentally during imaging investigations for other causes. However, more recent studies have demonstrated that BAA shows a frequent association with coarctation of the aorta (CoA), thoracic aortic disease (TAD), and stroke. At the same time, given the current context of increasing activity in the fields of interventional and surgical procedures in the aorta and its branches, it is very important to know the medical-surgical implications of this anatomical variant. (2) Methods: We conducted a comprehensive review using PubMed and Embase, focusing specifically on randomized trials and cohort analyses that examined the medical-surgical implications of BAA. We assessed information related to studied groups, medical procedures, and study outcomes. Initially, we identified 8454 studies, and after rigorous evaluation, we narrowed down our review to 25 articles. (3) Discussions: The intervention consisted of assessing the risks associated with BAA through different imaging investigation methods such as computer tomographic angiography (CTA), magnetic resonance imaging (MRI), or ultrasonography (US). The following results were evaluated: the prevalence of the BAA, the importance of imaging investigations in establishing the diagnosis and the therapeutic management and monitoring the evolution of patients with the BAA, the association of the BAA with CoA, TAD, and stroke, and the potential risks of interventional treatment in patients with the BAA. (4) Conclusions: The prevalence of the BAA differs both between different ethnic groups and between genders. Advanced imaging methods such as CTA and 4D flow MRI allow detailed descriptions of supra-aortic vascular anatomy and information about blood flow velocities, direction, and turbulence in the AA. US remains an easy and valuable imaging investigation, with the potential to detect and correctly diagnose the BAA and its hemodynamic implications. Anatomical variations in the AA are associated with increased rates of TAD, CoA, and stroke, necessitating early diagnosis and increased supervision of patients with such incidentally observed abnormalities. In addition, there is a need to further develop and refine the surgical techniques used and personalize them to the individual characteristics of patients with the BAA.

Surgical treatment strategies for patients with type A aortic dissection involving arch anomalies

Objective

The aim of the study was to investigate surgical modalities and outcomes in patients with type A aortic dissection involving arch anomalies.

Method

Patients with type A aortic dissection who underwent surgical treatment at our center between January 2017 and 31 December 2020 were selected for this retrospective analysis. Data including computed tomography (CT), surgical records, and cardiopulmonary bypass records were analyzed. Perioperatively survived patients were followed up, and long-term mortality and aortic re-interventions were recorded.

Result

A total of 81 patients with arch anomalies were included, 35 with “bovine” anomalies, 23 with an aberrant right subclavian artery, 22 with an isolated left vertebral artery, and one with a right-sided arch + aberrant left subclavian artery. The strategies of arch management and cannulation differed according to the anatomic variation of the aortic arch. In total, seven patients (9%) died after surgery. Patients with “bovine” anomalies had a higher perioperative mortality rate (14%) and incidence of neurological complications (16%). Overall, four patients died during the follow-up period, with a 6-year survival rate of 94.6% (70/74). A total of four patients underwent aortic re-intervention during the follow-up period; before the re-intervention, three received the en bloc technique (13.6% 3/22) and one received hybrid therapy (11.1% 1/9).

Conclusion

With complete preservation and reconstruction of the supra-arch vessels, patients with type A aortic dissection combining arch anomalies can achieve a favorable perioperative prognostic outcome. Patients who received the en bloc technique are more likely to require aortic re-intervention than patients who underwent total arch replacement with a four-branched graft vessel. Cannulation strategies should be tailored according to the variation of anatomy, but routine cannulation with the right axillary artery can still be performed in most patients with arch anomalies, even for patients with an aberrant right subclavian artery.

Risk factors for stroke after total aortic arch replacement using the frozen elephant trunk technique

OBJECTIVES

This study aimed to analyse risk factors for postoperative stroke, evaluate the underlying mechanisms and report on outcomes of patients suffering a postoperative stroke after total aortic arch replacement using the frozen elephant trunk technique.

METHODS

Two-hundred and fifty patients underwent total aortic arch replacement via the frozen elephant trunk technique between March 2013 and November 2020 for acute and chronic aortic pathologies. Postoperative strokes were evaluated interdisciplinarily by a cardiac surgeon, neurologist and radiologist, and subclassified to each's cerebral territory. We conducted a logistic regression analysis to identify any predictors for postoperative stroke.

RESULTS

Overall in-hospital was mortality 10% (25 patients, 11 with a stroke). A symptomatic postoperative stroke occurred in 42 (16.8%) of our cohort. Eight thereof were non-disabling (3.3%), whereas 34 (13.6%) were disabling strokes. The most frequently affected region was the arteria cerebri media. Embolism was the primary underlying mechanism (n = 31; 73.8%). Mortality in patients with postoperative stroke was 26.2%. Logistic regression analysis revealed age over 75 (odds ratio = 3.25; 95% confidence interval 1.20-8.82; P = 0.021), a bovine arch (odds ratio = 4.96; 95% confidence interval 1.28-19.28; P = 0.021) and an acute preoperative neurological deficit (odds ratio = 19.82; 95% confidence interval 1.09-360.84; P = 0.044) as predictors for postoperative stroke.

CONCLUSIONS

Stroke after total aortic arch replacement using the frozen elephant trunk technique remains problematic, and most lesions are of embolic origin. Refined organ protection strategies, and sophisticated monitoring are mandatory to reduce the incidence of postoperative stroke, particularly in older patients presenting an acute preoperative neurological deficit or bovine arch.

Prevalence of common origin of the innominate and left carotid artery (CILCA) or bovine arch configuration in patients with blunt aortic injury

BACKGROUND

The common origin of the innominate and left carotid artery (CILCA) have been described as a risk factor for thoracic aortic diseases (dissections and aneurysms), but its relationship with traumatic pathology of the thoracic aorta is not so well known. The aim of the present study is to describe the prevalence of CILCA among patients admitted to the hospital for high-energy polytrauma with aortic injury (BTAI) compared with a control group.

METHODS

Retrospective unicenter case-control study. Cases included all patients treated with BTAI between 1999-2020. The group of controls was patients admitted in our center for high-energy polytrauma between 2012-2017. Primary endpoint was to define the prevalence of CILCA among both groups and secondary endpoint was to measure the distance between brachiocephalic trunk (BCT) or left common carotid artery (LCCA) and left subclavian artery (LSA). Results were retrospectively reviewed by two investigators.

RESULTS

49 patients in BTAI group and 248 patients in control group. With a good concordance between investigators, 21 patients with CILCA (42.9%) in the BTAI group versus 61 CILCA (24.6%) in the control group (p=0.009). The mean distance between BCT/LCCA and LSA among the cases with CILCA was 10.09 mm (SD = 2.89) and 7.48 mm (SD = 3.65) among cases with standard aortic arch (p = 0.010).

CONCLUSIONS

In the present study we found that CILCA configuration is more prevalent in patients with BTAI and the distance to left subclavian artery is longer.

Aortic arch variant with a common origin of the innominate and left carotid artery as a determinant of thoracic aortic disease: a systematic review and meta-analysis

The aim of this study was to investigate whether the 'bovine' arch [i.e. arch variant with a common origin of the innominate and left carotid artery (CILCA)] is associated with an increased risk of thoracic aortic disease (TAD). The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The PubMed, EMBASE and Cochrane databases were searched to identify all case series reporting about CILCA arch and TAD between January 2008 and December 2018. A total of 485 studies were screened. The prevalence of CILCA arch was assessed, and data analysis was performed considering the difference in the risk of TAD for presence versus absence of CILCA arch. Eight studies enrolling 11 381 subjects were retrieved for quantitative analysis. The proportion of TAD among CILCA arch patients was higher [41.5% (28.1-56.4)] than the proportion among patients with standard arch configuration 34.0% (20.1-51.4). The odds ratio of developing TAD was 1.4 times higher in subjects with CILCA arch (95% confidence interval 1.068-1.839). The test for an overall effect indicated a significant association between CILCA arch and TAD (P < 0.015). The I2 was 78.1% with a value of P < 0.001 for heterogeneity. The Egger test did not show evidence of publication bias (P = 0.317). In conclusion, our meta-analysis supports the hypothesis of a correlation between the presence of CILCA arch and the onset of TAD. Our results warrant a specific and long-term surveillance for patients with this anatomical variant, and a thorough awareness of its potential clinical implications during image interpretation.

Brachiocephalic artery dissection is a marker of stroke after acute type A aortic dissection repair

OBJECTIVE

Postoperative stroke is a serious unsolved complication after acute type A aortic dissection (ATAAD) repair. We investigated the incidence and risk factors of stroke, and hypothesized that dissection of supra-aortic vessels is an important risk factor of this morbidity.

METHODS

Between 2012 and 2019, 202 (56% men, median age 68 years) patients with ATAAD underwent surgical repair. Clinical data, image findings, method of circulatory support, and repair technique were retrospectively investigated to explore the risk factor of postoperative stroke.

RESULTS

Of the 202 patients, operative mortality was 6% and the incidence of postoperative stroke was 12% (n = 25). Brachiocephalic artery (BCA) dissection was associated with a higher risk of stroke (odds ratio, 3.89; 95% confidence interval, 1.104-13.780; p = .035) having no relation to the presence or absence of left common carotid artery dissection. Preoperative malperfusion syndrome, circulatory arrest time, isolated cerebral perfusion time, repair technique (total arch replacement), and femoral artery perfusion alone were not related to the incident rate of postoperative stroke. Stroke occurred in both hemispheres, regardless of the laterality of carotid artery dissection.

CONCLUSION

BCA dissection was an independent risk factor of stroke after ATAAD repair.

Prevalence of Bovine Aortic Arch Variant in Patients with Aortic Dissection and its Implications in the Outcome of Patients with Acute Type B Aortic Dissection

OBJECTIVE/BACKGROUND

To investigate the prevalence of bovine arch (BA) among patients with type A and B aortic dissection, and to provide insight into the implication of this variation on the outcome of patients with acute or subacute type B aortic dissection (a/sTBAD).

METHODS

This retrospective cohort analysis includes patients with a/sTBAD admitted between January 2006 and December 2016. Computed tomographic angiograms (CTAs) of patients referred because of type A aortic dissection were also re-evaluated with regard to the presence of BA. As a control group, 110 oncological patients who had undergone a chest CTA for disease staging during the study period were enrolled. A total of 154 patients with a/sTBAD and 168 with type A aortic dissection were identified during the study period.

RESULTS

An overall prevalence of 17.6% for BA variants was revealed. The comparison between patients with aortic dissection and the control group showed no statistically significant difference in BA prevalence (17.7% vs. 17.3%; p = 1.0). No statistically significant difference in BA prevalence was observed when comparing patients with type A aortic dissection with those with type B aortic dissection (16.6% vs. 18.8%; p = .66). During a median follow-up period of 27.8 months, 30 patients died. The mortality rate among patients presenting a BA variant was 34.5%, whereas among patients without, it was 16.0% (p = .04). Multivariate analysis revealed the presence of a BA as an independent predictor of mortality (adjusted odds ratio 3.4, 95% confidence interval 1.2-9.8).

CONCLUSION

The BA should be considered as a predictor of the outcome for patients with type B aortic dissection.

Patient-specific finite element analysis of ascending aorta aneurysms

Catastrophic ascending aorta aneurysm (AsAA) dissection and rupture can be prevented by elective surgical repair, but identifying individuals at risk remains a challenge. Typically the decision to operate is based primarily on the overall aneurysm size, which may not be a reliable indicator of risk. In this study, AsAA inflation and rupture was simulated in 27 patient-specific finite element models constructed from clinical CT imaging data and tissue mechanical testing data from matching patients. These patients included n = 8 with concomitant bicuspid aortic valve (BAV), n = 10 with bovine aortic arch (BAA), and n = 10 with neither BAV nor BAA. AsAA rupture risk was found to increase with elevated systolic wall stress and tissue stiffness. The aortic size index was sufficient for identifying the patients with the lowest risk of rupture, but unsuitable for delineating between patients at moderate and high risk. There was no correlation between BAV or BAA and AsAA rupture risk; however, the AsAA morphology was different among these patients. These results support the use of mechanical parameters such as vessel wall stress and tissue stiffness for AsAA presurgical evaluation.