Endovascular Repair of Blunt Thoracic Aortic Trauma is Associated With Increased Left Ventricular Mass, Hypertension, and Off-target Aortic Remodeling

The optimal management of blunt aortic injury in the young

BACKGROUND

Blunt aortic injury (BAI) is relatively uncommon in the pediatric population. The goal of this study was to examine the management of BAI in both children and adolescents, using a large national dataset.

METHODS

Patients (1-19 years of age) with BAI were identified from the Trauma Quality Improvement Program (TQIP) database over 14-years. Patients were stratified by age group (children [ages 1-9] and adolescents [ages 10-19]) and compared. Multivariable logistic regression (MLR) analysis was performed to determine independent predictors of mortality in adolescents with BAI.

RESULTS

Adolescents undergoing TEVAR had similar morbidity (16.8 vs 12.6 ​%, p ​= ​0.057) and significantly reduced mortality (2.1 vs 14.4 ​%, p ​< ​0.0001) compared to those adolescents managed non-operatively. MLR identified use of TEVAR as the only modifiable risk factor significantly associated with reduced mortality (OR 0.138; 95%CI 0.059-0.324, p ​< ​0.0001).

CONCLUSIONS

BAI leads to significant morbidity and mortality for both children and adolescents. For pediatric patients with BAI, children may be safely managed non-operatively, while an endovascular repair may improve outcomes for adolescents.

A viscoelastic constitutive framework for aging muscular and elastic arteries

The evolution of arterial biomechanics and microstructure with age and disease plays a critical role in understanding the health and function of the cardiovascular system. Accurately capturing these adaptative processes and their effects on the mechanical environment is critical for predicting arterial responses. This challenge is exacerbated by the significant differences between elastic and muscular arteries, which have different structural organizations and functional demands. In this study, we aim to shed light to these adaptive processes by comparing the viscoelastic mechanics of autologous thoracic aortas (TA) and femoropopliteal arteries (FPA) in different age groups. We have extended our fractional viscoelastic framework, originally developed for FPA, to both types of arteries. To evaluate this framework, we analyzed experimental mechanical data from TA and FPA specimens from 21 individuals aged 13 to 73 years. Each specimen was subjected to a multi-ratio biaxial mechanical extension and relaxation test complemented by bidirectional histology to quantify the structural density and microstructural orientations. Our new constitutive model accurately captured the mechanical responses and microstructural differences of the tissues and closely matched the experimentally measured densities. It was found that the viscoelastic properties of collagen and smooth muscle cells (SMCs) in both the FPA and TA remained consistent with age, but the viscoelasticity of the SMCs in the FPA was twice that of the TA. Additionally, changes in collagen nonlinearity with age were similar in both TA and FPA. This model provides valuable insights into arterial mechanophysiology and the effects of pathological conditions on vascular biomechanics. STATEMENT OF SIGNIFICANCE: Developing durable treatments for arterial diseases necessitates a deeper understanding of how mechanical properties evolve with age in response to mechanical environments. In this work, we developed a generalized viscoelastic constitutive model for both elastic and muscular arteries and analyzed both the thoracic aorta (TA) and the femoropopliteal artery (FPA) from 21 donors aged 13 to 73. The derived parameters correlate well with histology, allowing further examination of how viscoelasticity evolves with age. Correlation between the TA and FPA of the same donors suggest that the viscoelasticity of the FPA may be influenced by the TA, necessitating more detailed analysis. In summary, our new model proves to be a valuable tool for studying arterial mechanophysiology and exploring pathological impacts.

How to TEVAR swine for scientific research: Technical, anatomic, and device considerations to translate human TEVAR techniques into the large animal laboratory

OBJECTIVE

Thoracic Endovascular Aortic Repair (TEVAR) is well established in humans. Despite widespread use, additional research questions related to thoracic aortic stenting and endovascular innovation require large animal models. Translating human TEVAR devices and techniques into animal models, however, is a challenge even for experienced endovascular surgeons looking to develop a large animal TEVAR model.This article describes swine-specific strategies to deploy human TEVAR stent grafts, delineate how to select, size, prepare, and re-use human stents and deployment systems in swine, and how to translate human imaging modalities to large animal TEVAR.

METHODS

We describe a selection of related TEVAR models and techniques in Yorkshire swine to support scientific inquiry. This includes an animal husbandry and pre-operative preparation and planning program. All imaged specimens in this paper are castrated male Yorkshire swine in the 60-80 kg range and underwent TEVAR with the Medtronic Navion stent and deployment system.

RESULTS

To study human aortic stent grafts in swine, the animals generally must be at least 50 kgs to guarantee a 2 cm internal aortic diameter at the left subclavian, and for the iliac arteries to accommodate the human deployment system. Swine will have longer torsos and shorter iliofemoral segments than a human of the same weight which can make human deployment systems too short to reach the left subclavian from the femoral arteries in larger animals. We provide techniques to overcome this, including open iliac access or upside-down carotid TEVAR, which may be particularly useful if the scientific data would be confounded by iliofemoral access.Unlike humans that present clinically with axial imaging, swine will generally not have preoperative imaging, and many translational research laboratories do not have access to inexpensive preoperative CT, or any intraoperative CT scanning, which we are fortunate to have. We describe, therefore, several strategies for imaging in this setting including TEVAR via C-arm fluoroscopy and with or without in-laboratory CT scanning. Due to the low-resource setting of most large animal laboratories, as compared to a human hybrid room, we also describe several techniques to reduce cost and reuse materials, including the stent grafts, which at the end of non-survival experiments can be recovered during necropsy, cleaned, reinserted into the deployment device and reused on additional animals.

CONCLUSIONS

This article describes a collection of related techniques and tips to translate human TEVAR imaging, sizing/selection, deployment, and anatomy to swine research. Using this framework alone, an experienced human vascular or endovascular surgeon may develop a complete aortic stenting animal model with strategies for scientific data acquisition.

Thoracic Endovascular Aortic RepairAcutely Augments Left Ventricular Biomechanics in An Animal Model: A Mechanism for Postoperative Heart Failure and Hypertension

BACKGROUND

Thoracic aortic stent grafts are thought to decrease aortic compliance and may contribute to hypertension and heart failure after thoracic endovascular aortic repair (TEVAR). Left ventricular (LV) biomechanics immediately after TEVAR, however, have not been quantified. Pressure-volume (PV) loop analysis provides gold-standard LV functional information. The aim of this study is to use an LV PV loop catheter and analysis to characterize the LV biomechanics before and acutely after TEVAR.

METHODS

Anesthetized Yorkshire swine (N = 6) were percutaneously instrumented with an LV PV loop catheter. A 20 mm × 10 cm stent graft was deployed distal to the left subclavian via the femoral artery under fluoroscopy. Cardiac biomechanics were assessed before and after TEVAR. As a sensitivity analysis, inferior vena cava occlusion with PV loop assessment was performed pre and post-TEVAR in 1 animal to obtain preload and afterload-independent end-systolic and end-diastolic PV relationships (ESPVR and EDPVR).

RESULTS

All animals underwent successful instrumentation and TEVAR. Post-TEVAR, all 6 animals had higher mean LV ESP (106 vs. 118 mm Hg, P = 0.04), with no change in the EDPVR. inferior vena cava occlusion also moved the ESPVR curve upward and leftward, indicating increased LV work per unit time. There was no augmentation of EDPVR following TEVAR (P > 0.05). Postmortem exams in all animals revealed appropriate stent placement and no technical complications.

CONCLUSIONS

TEVAR was associated with an acute increase in LV end-systolic pressure and shift in the ESPVR, indicating increased ventricular work. This data provides potential mechanistic insights into the development of post-TEVAR hypertension and heart failure. Future stent graft innovation should focus on minimizing the changes in cardiac physiology.

Incidence and risk factors for interval aortic events during staged fenestrated-branched endovascular aortic repair

OBJECTIVE

Staged endovascular repair of complex aortic aneurysms with first-stage thoracic endovascular aortic repair may decrease the risk of spinal cord ischemia (SCI) associated with fenestrated-branched endovascular aortic repair (FB-EVAR) of thoracoabdominal aortic aneurysms or optimize the proximal landing zone in the cases requiring total aortic arch repair. However, a limitation of multistaged procedures is the risk of interval aortic events (IAEs) including mortality from a ruptured aneurysm. We aim to identify the incidence of and risk factors associated with IAEs during staged FB-EVAR.

METHODS

This was a single-center, retrospective review of patients who underwent planned staged FB-EVAR from 2013 to 2021. Clinical and procedural details were reviewed. End points were the incidence of and risk factors associated with IAEs (defined as rupture, symptoms, and unexplained death) and outcomes in patients with or without IAEs.

RESULTS

Of 591 planned FB-EVAR patients, 142 underwent first-stage repairs. Twenty-two did not have a planned second stage because of frailty, preference, severe comorbidities, or complications after the first stage and were excluded. The remaining 120 patients (mean age: 73 ± 6 years, 51% female) were planned for second-stage completion FB-EVAR and comprised our cohort. The incidence of IAEs was 13% (16 of 120). This included confirmed rupture in 6 patients, possible rupture in 4, symptomatic presentation in 4, and early unexplained interval death with possible rupture in 2. The median time to IAEs was 17 days (range: 2-101 days), and the median time to uncomplicated completion repairs was 82 days (interquartile range: 30-147 days). Age, sex, and comorbidities were similar between the groups. There were no differences in familial aortic disease, genetically triggered aneurysms, aneurysm extent, or presence of chronic dissection. Patients with IAEs had significantly larger aneurysm diameters than those without IAEs (76.6 vs 66.5 mm, P ≤ .001). This difference persisted with indexing for body surface area (aortic size index: 3.9 vs 3.5 cm/m2, P = .04) and height (aortic height index: 4.5 vs 3.9 cm/m, P ≤ .001). IAE mortality was 69% (11 of 16) compared with no perioperative deaths for those with uncomplicated completion repairs.

CONCLUSIONS

The incidence of IAEs was 13% in patients planned for staged FB-EVAR. This represented a notable morbidity, including rupture, which must be balanced with SCI and landing zone optimization when planning repair. Larger aneurysms, especially when adjusted for body surface area, are associated with IAEs. Minimizing time between stages vs single-stage repairs for larger (>7 cm) complex aortic aneurysms in patients with reasonable SCI risk should be considered when planning repair.

Impact of thoracic endovascular aortic repair following blunt traumatic thoracic aortic injury on blood pressure

BACKGROUND

Blunt traumatic thoracic aortic injuries (BTAIs) are associated with a high mortality rate. Thoracic endovascular aortic repair (TEVAR) is the most frequently used surgical strategy in patients with BTAI, as it offers good short- and middle-term results. Previous studies have reported an abnormally high prevalence of hypertension (HT) in these patients. This work aimed to describe the long-term prevalence of HT and provide a comprehensive evaluation of the biomechanical, clinical, and functional factors involved in HT development.

METHODS

Twenty-six patients treated with TEVAR following BTAI with no history of HT at the time of trauma were enrolled. They were matched with 37 healthy volunteers based on age, sex, and body surface area and underwent a comprehensive follow-up study, including cardiovascular magnetic resonance, 24-hour ambulatory blood pressure monitoring, and assessment of carotid-femoral pulse wave velocity (cfPWV, a measure of aortic stiffness) and flow-mediated vasodilation.

RESULTS

The mean patient age was 43.5 ± 12.9 years, and the majority were male (23 of 26; 88.5%). At a mean of 120.2 ± 69.7 months after intervention, 17 patients (65%) presented with HT, 14 (54%) had abnormal nighttime blood pressure dipping, and 6 (23%) high cfPWV. New-onset HT was related to a more proximal TEVAR landing zone and greater distal oversizing. Abnormal nighttime blood pressure was related to high cfPWV, which in turn was associated with TEVAR length and premature arterial aging.

CONCLUSIONS

HT frequently occurs otherwise healthy subjects undergoing TEVAR implantation after BTAI. TEVAR stiffness and length, the proximal landing zone, and distal oversizing are potentially modifiable surgical characteristics related to abnormal blood pressure.

Ascending Aortic Endograft and Thoracic Aortic Deformation After Ascending Thoracic Endovascular Aortic Repair

PURPOSE

We aim to quantify multiaxial cardiac pulsatility-induced deformation of the thoracic aorta after ascending thoracic endovascular aortic repair (TEVAR) as a part of the GORE ARISE Early Feasibility Study.

MATERIALS AND METHODS

Fifteen patients (7 females and 8 males, age 73±9 years) with ascending TEVAR underwent computed tomography angiography with retrospective cardiac gating. Geometric modeling of the thoracic aorta was performed; geometric features including axial length, effective diameter, and centerline, inner surface, and outer surface curvatures were quantified for systole and diastole; and pulsatile deformations were calculated for the ascending aorta, arch, and descending aorta.

RESULTS

From diastole to systole, the ascending endograft exhibited straightening of the centerline (0.224±0.039 to 0.217±0.039 cm^-1, p<0.05) and outer surface (0.181±0.028 to 0.177±0.029 cm^-1, p<0.05) curvatures. No significant changes were observed for inner surface curvature, diameter, or axial length in the ascending endograft. The aortic arch did not exhibit any significant deformation in axial length, diameter, or curvature. The descending aorta exhibited small but significant expansion of effective diameter from 2.59±0.46 to 2.63±0.44 cm (p<0.05).

CONCLUSION

Compared with the native ascending aorta (from prior literature), ascending TEVAR damps axial and bending pulsatile deformations of the ascending aorta similar to how descending TEVAR damps descending aortic deformations, while diametric deformations are damped to a greater extent. Downstream diametric and bending pulsatility of the native descending aorta was muted compared with that in patients without ascending TEVAR (from prior literature). Deformation data from this study can be used to evaluate the mechanical durability of ascending aortic devices and inform physicians about the downstream effects of ascending TEVAR to help predict remodeling and guide future interventional strategies.

CLINICAL IMPACT

This study quantified local deformations of both stented ascending and native descending aortas to reveal the biomechanical impact of ascending TEVAR on the entire thoracic aorta, and reported that the ascending TEVAR muted cardiac-induced deformation of the stented ascending aorta and native descending aorta. Understanding of in vivo deformations of the stented ascending aorta, aortic arch and descending aorta can inform physicians about the downstream effects of ascending TEVAR. Notable reduction of compliance may lead to cardiac remodeling and long-term systemic complications. This is the first report which included dedicated deformation data regarding ascending aortic endograft from clinical trial.

Traumatic blunt thoracic aortic injury: a 10-year single-center retrospective analysis

BACKGROUND

Approximately 80% of patients with blunt thoracic aortic injury (BTAI) die before reaching the hospital. Most people who survive the initial injury eventually die without appropriate treatment. This study analyzed and reported the treatment strategy of a single center for BTAI in the last 10 years and the early and middle clinical results.

METHODS

This retrospective study included patients diagnosed with BTAI at Xijing Hospital from 2013 to 2022. All inpatients with BTAI aged ≥ 18 years were included in this study. The clinical data, imaging findings, and follow-up results were retrospectively collected and analyzed. The Kaplan-Meier curve and multivariate logistic regression were used to compare survivors and nonsurvivors.

RESULTS

A total of 72 patients (57% men) were diagnosed with BTAI, with a mean age of 54.2 ± 9.1 years. The injury severity score was 24.3 ± 18, with Grade I BTAI1 (1.4%), Grade II 17 (23.6%), Grade III 52 (72.2%), and Grade IV 2 (2.8%) aortic injuries. Traffic accidents were the main cause of BTAI in 32 patients (44.4%). Most patients had trauma, 37 had rib fractures (51.4%), Sixty patients (83.3%) underwent thoracic endovascular aortic repair (TEVAR) surgery, eight (11.1%) underwent conservative treatment, and only four (5.6%) underwent open surgery. The overall hospitalization mortality was 12.5%. In multivariate logistic regression, elevated creatinine levels (P = 0.041) and high Glasgow coma scale (GCS) score (P = 0.004) were the predictors of hospital mortality. The median follow-up period was 57 (28-87) months. During the follow-up period, all-cause mortality was 5.6% and no aortic-related deaths were reported. Three patients (4.2%) needed secondary surgery and two of them underwent endovascular repair.

CONCLUSION

Although TEVAR surgery may be associated with intra- or postoperative dissection rupture or serious complications in the treatment of Grade III BTAI, the incidence rate was only 8.9%. Nevertheless, TEVAR surgery remains a safe and feasible approach for the treatment of Grade II or III BTAI, and surgical treatment should be considered first,. A high GCS score and elevated creatinine levels in the emergency department were closely associated with hospital mortality. Younger patients need long-term follow-up after TEVAR.

Aortic Biomechanics and Clinical Applications

The aorta contributes to cardiovascular physiology and function. Understanding biomechanics in health, disease, and after aortic interventions will facilitate optimization of perioperative patient care.

Aortic Healing Appears to Occur Rapidly after Successful Endovascular Sealing of Blunt Thoracic Aortic Injury

OBJECTIVES

The traumatic nature of blunt thoracic aortic injury (BTAI) would suggest that healing of the aorta would occur once the injured area is shielded from aortic pressure. This would be in contrast to degenerative aortic diseases which often continue to degenerate despite coverage. We hypothesize that after successful thoracic aortic endografting (TEVAR) that the aorta rapidly heals itself leaving minimal to no trace of the residual injury.

METHODS

BTAI that were successfully covered with TEVAR from 2006-2019 were collected. Those with failed sealing or lack of follow up scans were excluded. Centerline aortic diameters were measured at healthy aorta 1 cm above (D1) and below the injury (D3) and at the widest point of injury (D2) on pre- and initial post-operative computed tomography (CT) scans. Post-operative CTs were examined for residual signs of aortic injury including residual peri-aortic hematoma, persistent thrombosed pseudoaneurysm, or thickened aortic wall. Diameter changes in the healthy and injured aortic segments were compared pre and post TEVAR. Aortic diameter changes were analyzed with Students t-test.

RESULTS

Twenty-four patients were identified with sealed BTAI. Mean graft diameter was 24.2 ± 3.2 mm with oversizing of 10.74 ± 6.1 % at D1 and 19.52 ± 10.22 % at D3. Postoperative CTs occurred at 61.25 ± 123.6 days with one outlier at 602 days. Injured aortic segments (D2) had significantly larger diameters compared to D1 (28.94 ± 5.08mm vs. 22.14 ± 3.08 mm, P<0.001).). After TEVAR, 23/24 (95.8%) had no residual radiographic evidence of aortic injury by 2 months. One patient had a persistent thrombosed pseudoaneurysm likely due to a more than 50% disruption of the aortic wall. Post TEVAR, there was a significant diameter reduction at D2 by 13.8% (29.10 ± 5.27mm vs. 24.8 ± 4.2 mm, p <0.001) which was within 2.45% of the mean stent graft diameter. Healthy aorta dilated to accommodate the graft by 9% at D1 (21.9 ± 3.0 vs. 23.7 ± 2.5 mm, p < 0.001) and 17% at D3 (20.6 ± 3.4 mm vs. 23.6 ± 3.2 mm, p < 0.001).

CONCLUSIONS

TEVAR promotes rapid aortic healing in BTAI with no evidence of residual aortic injury suggesting that a long term seal is not necessary. The healthy aorta dilates to the stent graft size, as expected, while the injured aortic segment heals around the stent graft and assumes its diameter as well. Massive disruption of the aortic wall may preclude early healing.

Calcification prevalence in different vascular zones and its association with demographics, risk factors, and morphometry

Vascular calcification is associated with a higher incidence of cardiovascular events, but its prevalence in different vascular zones and the influence of demographics, risk factors, and morphometry remain insufficiently understood. Computerized tomography angiography scans from 211 subjects 5-93 yr old (mean age 47 ± 24 yr, 127 M/84 F) were used to build 3D vascular reconstructions and measure arterial diameters, tortuosity, and calcification volumes in six vascular zones spanning from the ascending thoracic aorta to the pelvic arteries. A machine learning random forest algorithm was used to determine the associations between calcification in each zone with demographics, risk factors, and vascular morphometry. Calcification appeared during the fourth decade of life and was present in all subjects after 65 yr. The abdominal aorta and the iliofemoral segment were the first to develop calcification, whereas the ascending thoracic aorta was the last. Demographics and risk factors explained 33-59% of the variation in calcification. Age, creatinine level, body mass index, coronary artery disease, and hypertension were the strongest contributors, whereas the effects of sex, race, tobacco use, diabetes, dyslipidemia, and alcohol and substance use disorders on calcification were small. Vascular morphometry did not directly and independently affect calcium burden. Vascular zones develop calcification asynchronously, with distal segments calcifying first. Understanding the influence of demographics and risk factors on calcium prevalence can help better understand the disease pathophysiology and may help with the early identification of patients that are at higher risk of cardiovascular events.NEW & NOTEWORTHY We investigated the prevalence of vascular calcification in different zones of the aorta and pelvic arteries using computerized tomography angiography reconstructions and have applied machine learning to determine how calcification is affected by demographics, risk factors, and morphometry. The presented data can help identify patients at higher risk of developing vascular calcification that may lead to cardiovascular events.

Short Term Prognosis of Renal Artery Stenosis Secondary to Acute Type B Aortic Dissection With TEVAR

Objective: To determine the effect of renal artery stenosis (RAS) resulting from acute type B aortic dissection (ATBAD) with thoracic endovascular aortic repair (TEVAR) on early prognosis in patients with ATBAD.

Methods: A total of 129 ATBAD patients in the National Acute Aortic Syndrome Database (AASCN) who underwent TEVAR between 2019 and 2020 were enrolled in our study. Patients were divided into two groups: the RAS group and the non-RAS group.

Results: There were 21 RAS patients (16.3%) and 108 non-RAS patients (83.7%) in our cohort. No patient in our cohort died during the 1-month follow-up. There was no significant difference in preoperative creatinine clearance rate (CCr) between the two groups (90.6 ± 46.1 μmol/L in the RAS group vs. 78.7 ± 39.2 μmol/L in the non-RAS group, P = 0.303) but the RAS group had a significantly lower estimated glomerular filtration rate (eGFR) than the non-RAS group (83.3 ± 25.0 vs. 101.9 ± 26.9 ml/min, respectively; P = 0.028).One month after TEVAR, CCr was significantly higher (99.0 ± 68.1 vs. 78.5 ± 25.8 ml/min, P = 0.043) and eGFR (81.7 ± 23.8 vs. 96.0 ± 20.0 ml/min, P = 0.017) was significantly lower in the RAS group than in the non-RAS group.

Conclusions: In ATBAD, RAS could result in acute kidney injury (AKI) in the early stage after TEVAR. The RAS group had a high incidence of hypertension. These results suggest that patients with RAS may need further treatment.

Stent Graft Oversizing is Associated with an Increased Risk of Long-Term Left Ventricular Wall Thickening in Young Patients Following Thoracic Endovascular Aortic Repair

BACKGROUND

Left ventricular (LV) wall thickening occurs in patients following thoracic endovascular aortic repair (TEVAR). Clinical consequences of cardiovascular (CV) remodeling may be more significant younger patients with longer anticipated life spans. Risk factors for CV remodeling following TEVAR are unknown but may be related to graft size.

METHODS

A retrospective analysis was performed of a multicenter healthcare system including patients aged ≤60 who underwent TEVAR between 2011 and 2019 with at least 1 year follow-up computed tomography angiography imaging available. Standard perioperative variables, native aortic diameter, and stent graft specifications were collected. Graft oversizing was calculated by dividing proximal graft diameter by proximal aortic diameter on preoperative imaging. Posterior LV wall thickness was measured at baseline and interval increases were normalized to time-to-follow-up. Primary outcome was annual rate of posterior LV wall thickening.

RESULTS

One hundred one patients met inclusion criteria with a mean (SD) follow-up time of 1270 (693) days. Overall mean (SD) rate of LV wall thickness change was 0.534 (0.750) mm per year. Mean (SD) absolute LV wall thickness at most recent follow-up was 10.97 (2.85) mm for men, 9.69 (2.03) mm for women. Multivariate analysis demonstrated that higher rates of LV wall thickening were associated with narrower graft diameters (P = 0.0311). Greater absolute LV wall thickness at follow-up was associated with narrower grafts (P= 0.0155) and greater graft oversizing (P= 0.0376). Logistic regression demonstrated individuals who met criteria for LV hypertrophy were more likely to have narrower stent-grafts (P= 0.00798) and greater graft oversizing (P= 0.0315).

CONCLUSIONS

LV wall thickening occurred to a greater degree in individuals with narrower stent-grafts and higher rates of graft oversizing. This has significant implications for long-term cardiovascular health in younger patients may undergo TEVAR for atypical indications. Particular attention should be paid to long-term effects of stent-graft oversizing when selecting grafts in such populations.

Mechanical, structural, and physiologic differences in human elastic and muscular arteries of different ages: Comparison of the descending thoracic aorta to the superficial femoral artery

Elastic and muscular arteries differ in structure, function, and mechanical properties, and may adapt differently to aging. We compared the descending thoracic aortas (TA) and the superficial femoral arteries (SFA) of 27 tissue donors (average 41±18 years, range 13-73 years) using planar biaxial testing, constitutive modeling, and bidirectional histology. Both TAs and SFAs increased in size with age, with the outer radius increasing more than the inner radius, but the TAs thickened 6-fold and widened 3-fold faster than the SFAs. The circumferential opening angle did not change in the TA, but increased 2.4-fold in the SFA. Young TAs were relatively isotropic, but the anisotropy increased with age due to longitudinal stiffening. SFAs were 51% more compliant longitudinally irrespective of age. Older TAs and SFAs were stiffer, but the SFA stiffened 5.6-fold faster circumferentially than the TA. Physiologic stresses decreased with age in both arteries, with greater changes occurring longitudinally. TAs had larger circumferential, but smaller longitudinal stresses than the SFAs, larger cardiac cycle stretch, 36% lower circumferential stiffness, and 8-fold more elastic energy available for pulsation. TAs contained elastin sheets separated by smooth muscle cells (SMCs), collagen, and glycosaminoglycans, while the SFAs had SMCs, collagen, and longitudinal elastic fibers. With age, densities of elastin and SMCs decreased, collagen remained constant due to medial thickening, and the glycosaminoglycans increased. Elastic and muscular arteries demonstrate different morphological, mechanical, physiologic, and structural characteristics and adapt differently to aging. While the aortas remodel to preserve the Windkessel function, the SFAs maintain higher longitudinal compliance.

Thoracic endovascular aortic repair for traumatic aortic injuries: insight from literature and practical recommendations

INTRODUCTION

Thoracic endovascular aortic repair (TEVAR) for treatment of blunt traumatic aortic injuries (BTAIs) is nowadays the gold standard technique in adult patients, replacing gradually the use of open repair (OR). Although randomized controlled trials will never be performed comparing TEVAR to OR for BTAIs management, trauma and vascular societies guidelines today primarily recommend the former for BTAI patients with a suitable anatomy. The aim of this review was to describe past and recent data published in literature regarding pros and cons of TEVAR treatment in BTAI, and to analyze some debated issues and future perspectives.

EVIDENCE ACQUISITION

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and Scale for the Assessment of Narrative Review Articles (SANRA) were used to obtain and describe selected articles on TEVAR in BTAI.

EVIDENCE SYNTHESIS

Young (<50 years) men were the most operated population. The use of TEVAR increased over the years, with a progressive reduction in mortality and overall postoperative complication rates when compared with OR. Lack of information remains about the percentage of urgent cases.

CONCLUSIONS

TEVAR is considered nowadays the treatment of choice in BTAI patients. In case of aortic rupture (grade IV) the treatment is mandatory, while intimal tear (grade I) and intramural hematoma (grade II) can be safely managed with no operative management (NOM). Debate is still ongoing on grade III (pseudoaneurysms). Unfortunately, several aspects remain not yet clarified, including disease classification, type and grade to treat, timing (urgent versus elective), priority of vascular injuries in polytrauma patients, and TEVAR use in pediatrics and young patients.