Characterizing Tissue Remodeling and Mechanical Heterogeneity in Cerebral Aneurysms.

Accurately assessing the complex tissue mechanics of cerebral aneurysms (CAs) is critical for elucidating how CAs grow and whether that growth will lead to rupture. The factors that have been implicated in CA progression - blood flow dynamics, immune infiltration, and extracellular matrix remodeling - all occur heterogeneously throughout the CA. Thus, it stands to reason that the mechanical properties of CAs are also spatially heterogeneous. Here, we present a new method for characterizing the mechanical heterogeneity of human CAs using generalized anisotropic inverse mechanics, which uses biaxial stretching experiments and inverse analyses to determine the local Kelvin moduli and principal alignments within the tissue. Using this approach, we find that there is significant mechanical heterogeneity within a single acquired human CA. These results were confirmed using second harmonic generation imaging of the CA's fiber architecture and a correlation was observed. This approach provides a single-step method for determining the complex heterogeneous mechanics of CAs, which has important implications for future identification of metrics that can improve accuracy in prediction risk of rupture.

Emergency Repair of a Ruptured Para-Renal Abdominal Aortic Aneurysm in a Patient with a Functional Renal Graft: A Case Report and Review of the Literature.

INDRODUCTION: Rupture of and abdominal aortic aneurysm (AAA) in a kidney transplant patient is a rare and rarely reported event. Emergent treatment can be challenging and should achieve effective aortic repair while minimizing ischemic damage to the renal graft during aortic cross-clamping. Several renal protective measures have been proposed such as permanent or temporary shunts, renal cold perfusion and general hypothermia. CASE REPORT: We report the effective treatment of a para-renal AAA in a patient with a functional renal allograft. A temporary extra-corporeal axillofemoral shunt was constructed to maintain graft's perfusion during open surgical repair. EVAR was not an option due to a short aortic neck. The postoperative period was complicated by colon ischemia and aortic graft infection. At 3 years follow-up the patient was well and graft's function was unchanged. CONCLUSION: This case is a reminder that renal graft protection must be accounted for when AAA rupture occurs in kidney transplant patients. We reviewed the literature to find previously reported cases and how they were managed.

Stress Analysis in AAA does not Predict Rupture Location Correctly in Patients with Intraluminal Thrombus.

BACKGROUND: A biomechanical approach to the rupture risk of an abdominal aortic aneurysm could be a solution to ensure a personalized estimate of this risk. It is still difficult to know in what conditions, the assumptions made by biomechanics, are valid. The objective of this work was to determine the individual biomechanical rupture threshold and to assess the correlation between their rupture sites and the locations of their maximum stress comparing two computed tomography scan (CT) before and at time of rupture. METHODS: We included 5 patients who had undergone two CT; one within the last 6 months period before rupture and a second CT scan just before the surgical procedure for the rupture. All DICOM data, both pre- and rupture, were processed following the same following steps: generation of a 3D geometry of the abdominal aortic aneurysm, meshing and computational stress analysis using the finite element method. We used two different modelling scenarios to study the distribution of the stresses, a "wall" model without intraluminal thrombus (ILT) and a "thrombus" model with ILT. RESULTS: The average time between the pre-rupture and rupture CT scans was 44 days (22-97). The median of the maximum stresses applied to the wall between the pre-rupture and rupture states were 0.817 MPa (0.555-1.295) and 1.160 MPa (0.633-1.625) for the "wall" model; and 0.365 MPa (0.291-0.753) and 0.390 MPa (0.343-0.819) for the "thrombus" model. There was an agreement between the site of rupture and the location of maximum stress for only 1 patient, who was the only patient without ILT. CONCLUSIONS: We observed a large variability of stress values at rupture sites between patients. The rupture threshold strongly varied between individuals depending on the intraluminal thrombus. The site of rupture did not correlate with the maximum stress except for 1 patient.

Inherited Thoracic Aortic Disease: New Insights and Translational Targets.

Inherited thoracic aortopathies denote a group of congenital conditions that predispose to disease of the thoracic aorta. Aortic wall weakness and abnormal aortic hemodynamic profiles predispose these patients to dilatation of the thoracic aorta, which is generally silent but can precipitate aortic dissection or rupture with devastating and often fatal consequences. Current strategies to assess the future risk of aortic dissection or rupture are based primarily on monitoring aortic diameter. However, diameter alone is a poor predictor of risk, with many patients experiencing dissection or rupture below current intervention thresholds. Developing tools that improve the risk assessment of those with aortopathy is internationally regarded as a research priority. A robust understanding of the molecular pathways that lead to aortic wall weakness is required to identify biomarkers and therapeutic targets that could improve patient management. Here, we summarize the current understanding of the genetically determined mechanisms underlying inherited aortopathies and critically appraise the available blood biomarkers, imaging techniques, and therapeutic targets that have shown promise for improving the management of patients with these important and potentially fatal conditions.

Hemodynamic Changes in an Actively Rupturing Abdominal Aortic Aneurysm.

Computational fluid dynamics were used to assess hemodynamic changes in an actively rupturing abdominal aortic aneurysm (AAA) over a 9-day period. Active migration of contrast from the lumen into the thickest region of intraluminal thrombus (ILT) was demonstrated until it ultimately breached the adventitial layer. Four days after symptom onset, there was a discrete disruption of adventitial calcium with bleb formation at the site of future rupture. Rupture occurred in a region of low wall shear stress and was associated with a marked increase in AAA diameter from 6.6 to 8.4 cm. The cross-sectional area of the flow lumen increased across all time points from 6.28 to 12.08 cm2. The increase in luminal area preceded the increase in AAA diameter and was characterized by an overall deceleration in recirculation flow velocity with a coinciding increase in flow velocity penetrating the ILT. We show that there are significant hemodynamic and structural changes in the AAA flow lumen in advance of any appreciable increase in aortic diameter or rupture. The significant increase in AAA diameter with rupture suggests that AAA may actually rupture at smaller sizes than those measured on day of rupture. These findings have implications for algorithms the predict AAA rupture risk.

Preoperative risk score accuracy confirmed in a modern ruptured abdominal aortic aneurysm experience.

OBJECTIVE: Various risk score calculators used to predict 30-day mortality after treatment of ruptured abdominal aortic aneurysms (rAAAs) have produced mixed results regarding their usefulness and reproducibility. We prospectively validated the accuracy of our preoperative scoring system in a modern cohort of patients with rAAAs. METHODS: A retrospective review of all patients wiith rAAAs who had presented to a single academic center from January 2002 to December 2018 was performed. The patients were divided into three cohorts according to when the institutional practice changes had occurred: the pre-endovascular aneurysm repair (EVAR) era (January 2002 to July 2007), the pre-Harbor View risk score era (August 2007 to October 2013), and the modern era (November 2013 to December 2018). The primary outcome measure was 30-day mortality. Our preoperative risk score assigns 1 point for each of the following: age >76 years, pH <7.2, creatinine >2 mg/dL, and any episode of hypotension (systolic blood pressure <70 mm Hg). The previously reported mortality from a retrospective analysis of the first two cohorts was 22% for 1 point, 69% for 2 points, 78% for 3 points, and 100% for 4 points. The goal of the present study was to prospectively validate the Harborview scoring system in the modern era. RESULTS: During the 17-year study period, 417 patients with rAAAs were treated at our institution. Of the 118 patients treated in the modern era, 45 (38.1%) had undergone open aneurysm repair (OAR), 61 (51.7%) had undergone EVAR, and 12 (10.2%) had received comfort measures only. Excluding the 12 patients without aneurysm repair, we found a statistically significant linear trend between the preoperative risk score and subsequent 30-day mortality for all patients combined (P < .0001), for OAR patients alone (P = .0003), and for EVAR patients alone (P < .0001). After adjustment for the Harborview risk score, the 30-day mortality was 41.3% vs 31.6% after OAR vs EVAR, respectively (P = .2). For all repairs, the 30-day mortality was 14.6% for a score of 0, 35.7% for a score of 1, 68.4% for a score of 2, and 100% for a score of 3 or 4. CONCLUSIONS: Our results, representing one of the largest modern series of rAAAs treated at a single institution, have confirmed the accuracy of a simple 4-point preoperative risk score in predicting 30-day mortality in the modern rAAA patient. Such tools should be used when discussing the treatment options with referring physicians, patients, and their family members to help guide transfer and treatment decision-making.

Early and midterm results from a postmarket observational study of Zenith t-Branch thoracoabdominal endovascular graft.

OBJECTIVE: We have reported the short-term outcomes regarding the safety of the off-the-shelf Zenith t-Branch multibranched thoracoabdominal stent-graft (William Cook Europe ApS, Bjaeverskov, Denmark) in a postmarket, multicenter study. METHODS: Patients who had been treated with the t-Branch device from September 2012 to November 2017 at three European centers were either prospectively or retrospectively enrolled in the present study. Device implantation and postprocedural follow-up were performed according to the standard of care at each center. The primary objectives of the present study were to assess the procedure-related mortality and morbidity at 30 days and 1 year and to assess the presence of endoleaks, device integrity, and stent-graft and branch vessel patency. RESULTS: A total of 80 patients were included in the present study (mean age, 71.0 ± 7.4 years; 70.0% male). Most (n = 77) had been treated for thoracoabdominal aortic aneurysms (TAAAs) and the rest for dissection (n = 3). Most TAAAs were stable (72.7%; 56 of 77). The remaining TAAAs were symptomatic (7.8%; 6 of 77) or had a contained rupture (19.5%; 15 of 77). The t-Branch device was successfully deployed in 79 patients. In one patient, the delivery system of the device could not be advanced through the iliac artery. Within 30 days, one patient had died (1.3%). At 1 year, seven patients had died (8.8%), and no aortic rupture or conversion to open surgery had been reported. The 30-day neurologic events included stroke in three patients (3.8%), paraplegia in one (1.3%), and paraparesis in six patients (7.5%). Secondary interventions were required in nine patients (11.3%) during follow-up. Postoperative endoleaks were observed in 37 of 72 patients (51.4%), including type II endoleak in 30, type Ia in 4, and type III endoleak in 6 patients. At 1 year, endoleaks had been reported in 20 patients (16 with type II and 4 with type III). The t-Branch main body graft patency was 100% throughout the 1-year follow-up period. At 30 days after the procedure, all celiac and superior mesenteric artery branches were patent and one left renal and one right renal branch were occluded. At 1 year, occlusion had developed in three bridging stent-grafts for the celiac artery, one for the left renal artery, and two for the right renal artery. CONCLUSIONS: The t-Branch device appears safe, with good 30-day and 1-year mortality and morbidity in the present study, including both stable and symptomatic cases.

Comparison of peak wall stress and peak wall rupture index in ruptured and asymptomatic intact abdominal aortic aneurysms.

BACKGROUND: Previous studies have suggested that finite element analysis (FEA) can estimate the rupture risk of an abdominal aortic aneurysm (AAA); however, the value of biomechanical estimates over measurement of AAA diameter alone remains unclear. This study aimed to compare peak wall stress (PWS) and peak wall rupture index (PWRI) in participants with ruptured and asymptomatic intact AAAs. METHODS: The reproducibility of semiautomated methods for estimating aortic PWS and PWRI from CT images was assessed. PWS and PWRI were estimated in people with ruptured AAAs and those with asymptomatic intact AAAs matched by orthogonal diameter on a 1 : 2 basis. Spearman's correlation coefficient was used to assess the association between PWS or PWRI and AAA diameter. Independent associations between PWS or PWRI and AAA rupture were identified by means of logistic regression analyses. RESULTS: Twenty individuals were included in the analysis of reproducibility. The main analysis included 50 patients with an intact AAA and 25 with a ruptured AAA. Median orthogonal diameter was similar in ruptured and intact AAAs (82·3 (i.q.r. 73·5-92·0) versus 81·0 (73·2-92·4) mm respectively; P = 0·906). Median PWS values were 286·8 (220·2-329·6) and 245·8 (215·2-302·3) kPa respectively (P = 0·192). There was no significant difference in PWRI between the two groups (P = 0·982). PWS and PWRI correlated positively with orthogonal diameter (both P < 0·001). Participants with high PWS, but not PWRI, were more likely to have a ruptured AAA after adjusting for potential confounders (odds ratio 5·84, 95 per cent c.i. 1·22 to 27·95; P = 0·027). This association was not maintained in all sensitivity analyses. CONCLUSION: High aortic PWS had an inconsistent association with greater odds of aneurysm rupture in patients with a large AAA.

Ruptured sinus of valsalva aneurysm presenting as syncope and hypotension: a case report.

BACKGROUND: Unruptured sinus of valsalva aneurysm (SOVA) are typically asymptomatic, and hence can be easily ignored. Ruptured sinus of valsalva aneurysm (RSOVA) usually protrude into the right atrium or ventricular. However, in this case, the RSOVA protruded into the space between the right atrium and the visceral pericardium leading to compression of the right proximal coronary artery. Very few such cases have been reported till date. CASE PRESENTATION: We describe a case of ruptured right SOVA in a 61-year-old man with syncope and persistent hypotension. At the beginning, considered the markedly elevated troponin, acute myocardial infarction was considered. However, emergency coronary angiography unexpectedly revealed a large external mass compressed right coronary artery (RCA) resulting in severe proximal stenosis. Then, aorta computed tomography angiography (CTA) and urgent surgery confirmed that the ruptured right SOVA led to external compression of the right proximal coronary artery. Finally, ruptured right SOVA repair and RCA reconstruction were successfully performed, and the patient was discharged with no residual symptoms. CONCLUSIONS: It is very important to be vigilant about the existence of SOVA. RSOVA should be suspected in a patient presenting with acute hemodynamic compromise, and echocardiography should be immediately performed. Moreover, it is very important to achieve dynamic monitoring by using cardiac color ultrasound. Definitive diagnosis often requires cardiac catheterization, and an aortogram should be performed unless endocarditis is suspected.

Biomechanical Analysis of Cadaveric Thoracic Aorta Zones: The Isthmus is the Weakest Region.

BACKGROUND: The thoracic aorta is a site of multiple pathological processes, such as aneurysms and dissections. When considering the development of endovascular devices, this vessel has been extensively manipulated because of aortic diseases, as well as to serve as a route for procedures involving the head and neck vessels. Therefore, the aim of the present study was to obtain biomechanical experimental information about the strength and deformability of this vessel. MATERIALS AND METHODS: Thirty-one thoracic aorta specimens were harvested during the autopsy procedure. They were carefully dissected and transversally sectioned according to Criado's aortic arch map landing zones (0 to 4). The supra-aortic trunks were removed, and the aortic rings were opened in their convexity, which resulted in flat tissue segments. Four millimeter-wide strips were prepared from each zone after which they were attached to a clip system connected to the INSTRON SPEC 2200 device, which was responsible for pulling the fragment up to its rupture during the uniaxial tension test. The INSPEC software was used to coordinate the test, and data management was conducted via the SERIES IX software. The biomechanical variables that were measured included failure stress, failure tension, and failure strain. RESULTS: When comparing the five segments from all 31 aortas, three different strength levels were observed. Zones 0 and 1 exhibited the highest failure stress and failure tension values, followed by Zones 2 and 4. Zone 3 (aortic isthmus) was the weakest segment that was tested when compared to the stress and tension of Zones 0 and 1 (P < 0.001), the stress and tension of Zone 2 (P = 0.005 and P = 0.002, respectively) and the stress and tension of Zone 4 (P = 0.023 and P = 0.006, respectively). Among donors > 65 years-old, women presented significantly weaker descending aortas than men in regards to stress (P = 0.049) and tension (P = 0.014). Among male donors, the elderly donors presented significantly stiffer aortic walls and weaker ascending (P = 0.029 for stress) and descending (P = 0.004 for stress; P = 0.031 for tension) aortas than younger men. CONCLUSIONS: Uniaxial tensile strength tests revealed that the thoracic aorta is a very heterogeneous vessel. Isthmus frailty may add to the understanding of the pathophysiology of some aortic diseases that commonly compromise this region. The lower strength that was verifiedin some aortic segments from elderly donors may contribute to the genesis of some thoracic aorta diseases among that group of donors. These data can contribute to the development of new endovascular devices that are specifically designed for this vessel.

Experimental Study of Rupture Pressure and Elasticity of Abdominal Aortic Aneurysms Found at Autopsy.

BACKGROUND: Resistance and elasticity of normal and aneurysmal aorta walls are directly associated with this vessel's growth and rupture. This study aims to experimentally analyze the biomechanical behavior of aneurysmal specimens found at autopsy, comparing them with normal diameter aortas removed from age-matched donors. METHODS: Thirty-eight human aortas (30 normal aortas; 8 infrarenal abdominal aortic aneurysms) were harvested during autopsy. An apparatus was built with a digital gauge, plastic tray, connections, and hoses that conducted fluid (air) from a pump through the system. Specimens were dissected, and a flexible balloon was introduced in each of them to avoid leakage. The specimens were fastened on the test tray, and activation of the air pump enhanced system pressure up to their rupture. RESULTS: All 8 aneurysms and all 30 normal aortas specimens evolved to rupture under inflation pressures above 590 mm Hg (mean ± standard deviation = 1,035 ± 375 mm Hg) and 840 mm Hg (mean ± SD = 1,405 ± 342 mm Hg), respectively. In the aneurysm group, 25% of specimens did not rupture in their most dilated region. Percentage of increment in diameter was higher in normal aortas (mean ± SD = 0.2106 ± 0.144) than in aneurysms (mean ± SD = 0.093 ± 0.070). CONCLUSIONS: In the present experiment, unruptured infrarenal abdominal aortic aneurysms could support high pressures nearly as much as nonaneurysmal abdominal aortas. In some specimens, the most dilated part of the aneurysm was not the most vulnerable under pressure. Normal aortas presented higher elasticity than aneurysms.

Multiple Chimney Endografts (ChEVAR) for Ruptured Pararenal Aortic Aneurysm.

We present a ruptured pararenal abdominal aortic aneurysm repaired with a complex three-vessel chimney EVAR . This technique allows for rapid sealing of the aneurysm with branch preservation and avoids complex open aortic surgery. This case report highlights techniques and pitfalls from complex three-vessel chimney EVAR repair in the emergency setting.

Reasons for and Outcomes of Open Abdominal Aortic Repair in the Endovascular Era.

BACKGROUND: Endovascular aortic aneurysm repair (EVAR) has become the treatment of choice for most patients with abdominal aortic aneurysm (AAA). Open aneurysm repair (OAR) is still being used in a number of patients for specific reasons. The aim of the present study was to investigate the reasons and perioperative outcomes of OAR in a high-volume endovascular center. METHODS: All patients who underwent OAR in a single center institution during the period April 2010 to July 2019 were retrospectively analyzed. RESULTS: During the study period, 222 patients underwent OAR. One hundred and forty-one (63.5%) patients underwent elective surgery, and eighty-one (36.5%) patients were treated acutely. The reasons for the decision to perform OAR instead of EVAR were as follows: anatomical in 89 (40.1%) cases, rupture in unstable patient in 57 (25.7%) cases, AAA with concomitant iliac arterial occlusive disease in 44 (19.8%) cases, previous EVAR with complications in 14 (6.3%) cases, large pararenal aneurysm considered risky to wait for a customized fenestrated stent graft in 7 (3.2%) cases, young patient age in 4 (1.8%) cases, the patient's preference in 3 (1.4%) cases, infected/mycotic AAA in 2 (0.9%) cases, and simultaneous OAR with colon cancer resection (n = 1, 0.5%) and renal transplantation (n = 1, n = 0.5). Thirty-day mortality in elective cases was 5% (7/141) and in acute cases 34.6% (28/81). CONCLUSIONS: This study shows that OAR is still used for selected patients despite improvements in EVAR technology. The most common reason for OAR was an unsuitable anatomy for EVAR. Perioperative mortality of OAR both for acute and elective cases as observed in this study is in line with published outcomes of other centers.

Amplatzer Vascular Plug Embolization in Two Patients with Ruptured Infrarenal Aortic Aneurysm and Aortoiliac Occlusive Disease.

Mortality for ruptured abdominal aortic aneurysm (AAA) is known to be high. When left untreated, it is nearly always fatal. Standard treatment options include open surgery and endovascular aneurysm repair (EVAR), but both techniques have limitations. Owing to comorbidities and anatomical constraints, some patients are deemed unsuitable for both open surgery and EVAR. In these patients, alternative treatment strategies can be of special interest. To our knowledge, these are the first two cases reported using an Amplatzer Vascular Plug II for aortic embolization in patients with coexisting aneurysmatic and aorto-bi-iliac occlusive disease requiring urgent treatment for contained AAA rupture. Successful aneurysm exclusion was noted at follow-up ranging from 5 months to 3 years, and no procedure-related complications occurred. We therefore believe that in selected patients, this could be an elegant alternative in life-threatening situations with sustained occlusion in the mid-term.

Prediction of Distal Aortic Enlargement after Proximal Repair of Aortic Dissection Using Machine Learning.

OBJECTIVES: This study aimed to construct a risk prediction model for distal aortic enlargement in patients with type B aortic dissection (TBAD) treated with proximal thoracic endovascular aortic repair (TEVAR). METHODS: From June 2010 to June 2016, patients with TBAD who underwent proximal TEVAR were retrospectively analyzed. A total of 38 clinical and imaging variables were collected. Univariable logistic regression was conducted to explore potential risk factors associated with distal aortic enlargement. Elastic net regression was employed to select significantly influential variables. Then, machine learning algorithms (logistic regression (LR), artificial neutral network (ANN), random forest and support vector machine) were applied to build risk prediction models. The area under the receiver operating characteristic curve (AUC), sensitivity and specificity were used to evaluate the performance of these models. RESULTS: A total of 503 patients were enrolled in this study. During the follow-up, 105 (20.9%) patients were identified as having distal aortic enlargement, and 69 (13.7%) patients were found to have distal aortic aneurysm formation. Five patients were identified with aortic rupture. True lumen collapse and multi-false lumens were two potential risk factors for distal aortic enlargement after proximal repair of TBAD. The LR model performed the best in predicting distal aortic enlargement, with the highest sensitivity (96.7%) and an AUC of 0.773. The best model for predicting distal aneurysm formation was the ANN model, which yielded the highest AUC (0.876) and a specificity of 79.1%. CONCLUSIONS: Machine learning approaches can produce accurate predictions of distal aortic enlargement after proximal repair of TBAD, which potentially benefits subsequent management.

Biomechanical indices are more sensitive than diameter in predicting rupture of asymptomatic abdominal aortic aneurysms.

OBJECTIVE: Several studies of biomechanical rupture risk assessment (BRRA) showed its advantage over the diameter criterion in rupture risk assessment of abdominal aortic aneurysm (AAA). However, BRRA studies have not investigated the predictability of biomechanical risk indices at different time points ahead of rupture, nor have they been performed blinded for biomechanical analysts. The objective of this study was to test the predictability of the BRRA method against diameter-based risk indices in a quasi-prospective patient cohort study. METHODS: In total, 12 women and 31 men with intact AAAs at baseline have been selected retrospectively at two medical centers. Within 56 months, 19 cases ruptured, whereas 24 cases remained intact within 2 to 56 months. This outcome was kept confidential until all biomechanical activities in this study were finished. The biomechanical AAA rupture risk was calculated at baseline using high-fidelity and low-fidelity finite element method models. The capability of biomechanics-based and diameter-based risk indices to predict the known outcomes at 1 month, 3 months, 6 months, 9 months, and 12 months after baseline was validated. Besides common cohort statistics, the area under the curve (AUC) of receiver operating characteristic curves has been used to grade the different rupture risk indices. RESULTS: Up to 9 months ahead of rupture, the receiver operating characteristic analysis of biomechanics-based risk indices showed a higher AUC than diameter-based indices. Six months ahead of rupture, the largest difference was observed with an AUC of 0.878 for the high-fidelity biomechanical risk index, 0.859 for the low-fidelity biomechanical risk index, 0.789 for the diameter, and 0.821 for the sex-adjusted diameter. In predictions beyond 9 months, none of the risk indices proved to be superior. CONCLUSIONS: High-fidelity biomechanical modeling improves the predictability of AAA rupture. Asymptomatic AAA patients with high biomechanical AAA rupture risk indices have an increased risk of rupture. Integrating biomechanics-based diagnostic indices may significantly decrease the false-positive rate in AAA treatment. CLINICAL RELEVANCE: Rupture of abdominal aortic aneurysm (AAA) is the tenth leading cause of death in men older than 60 years; however, the currently used maximal diameter criterion has a high false-positive rate. In this study, we have compared this criterion with biomechanical rupture risk assessment on the unique data set of 43 asymptomatic AAAs, of which 19 ruptured later. Moreover, the AAA outcome was blinded to the operator for the first time. Our data demonstrated that the biomechanical rupture risk assessment is superior to maximal diameter in predicting AAA rupture up to 9 months ahead and significantly decreases the false-positive rate.

A systematic review and meta-analysis of endovascular versus open surgical repair for the traumatic ruptured thoracic aorta.

OBJECTIVE: The purpose of this study was to compare clinical outcomes between open repair and thoracic endovascular aortic repair (TEVAR) in traumatic ruptured thoracic aorta. METHODS: A comprehensive search was undertaken of the four major databases (PubMed, Embase, Scopus, and Ovid) to identify all published data comparing open vs endovascular repair. Databases were evaluated to July 2018. Odds ratios (ORs), weighted mean differences, or standardized mean differences and their 95% confidence intervals (CIs) were analyzed. The primary outcomes were stroke, paraplegia, and 30-day mortality rates; secondary outcomes were requirement for reintervention and 1-year and five-year mortality rates. RESULTS: A total of 1968 patients were analyzed in 21 articles. TEVAR was performed in 29% (n = 578) and open repair in 71% (n = 1390). TEVAR and open repair did not differ in the mean age of patients (42.1 ± 14 years vs 44.1 ± 14 years; P = .48). There was no difference in duration of intensive care and total hospital stay between TEVAR and open repair groups (12.7 ± 11.1 days vs 12.6 ± 8 days [P = .35] and 27.5 ± 14.6 days vs 25.9 ± 11 days [P = .80], respectively). Similarly, no statistically significant difference in postoperative paraplegia or stroke rate was noted between TEVAR and open repair (1.4% vs 2.3% [OR, 1.27; 95% CI, 0.59-2.70; P = .54] and 1% vs 0.5% [OR, 0.63; 95% CI, 0.18-2.18; P = .46]). Lower 30-day and 1-year mortality was noted in TEVAR (7.9% vs 20% [OR, 2.94; 95% CI, 1.92-4.49; P < .00001] and 8.7% vs 17% [OR, 2.11; 95% CI, 0.99-4.52; P = .05]). There was no difference in 5-year mortality (23% vs 17%; OR, 0.07; 95% CI, -0.07 to 0.20; P = .33). However, there was a higher rate of reintervention at 1 year in the endovascular group (0% vs 6%; OR, 0.17; 95% CI, 0.03-0.96; P = .04). CONCLUSIONS: TEVAR carries lower in-hospital mortality and provides satisfactory perioperative outcomes compared with open repair in traumatic ruptured thoracic aorta. It also provides a favorable 1-year survival at the expense of higher reintervention rates.

Vitamin D deficiency promotes large rupture-prone abdominal aortic aneurysms and cholecalciferol supplementation limits progression of aneurysms in a mouse model.

Vitamin D deficiency has been associated with human abdominal aortic aneurysm (AAA); however, its role in AAA pathogenesis is unclear. The aim of the present study was to investigate the effect of vitamin D deficiency on AAA development and examine if administering cholecalciferol (CCF) could limit growth of established AAA within the angiotensin-II (AngII) infused apolipoprotein E-deficient mouse model. Mice were rendered vitamin D deficiency through dietary restriction and during AngII infusion developed larger AAAs as assessed by ultrasound and ex vivo morphometry that ruptured more commonly (48% vs. 19%; P=0.028) than controls. Vitamin D deficiency was associated with increased aortic expression of osteopontin and matrix metalloproteinase-2 and -9 than controls. CCF administration to mice with established aortic aneurysms limited AAA growth as assessed by ultrasound (P<0.001) and ex vivo morphometry (P=0.036) and reduced rupture rate (8% vs. 46%; P=0.031). This effect was associated with up-regulation of circulating and aortic sclerostin. Incubation of human aortic smooth muscle cells with 1,25-dihyroxyvitamin D3 (the active metabolite of vitamin D) for 48 h induced up-regulation of sclerostin (P<0.001) and changed the expression of a range of other genes important in extracellular matrix remodeling. The present study suggests that vitamin D deficiency promotes development of large rupture-prone aortic aneurysms in an experimental model. CCF administration limited both growth and rupture of established aneurysms. These effects of vitamin D appeared to be mediated via changes in genes involved in extracellular matrix remodeling, particularly sclerostin.

Is There a Relationship Between Stress in Walls of Abdominal Aortic Aneurysm and Symptoms?

BACKGROUND: Abdominal aortic aneurysm (AAA) is a permanent and irreversible dilation of the lower region of the aorta. It is typically an asymptomatic condition that if left untreated can expand to the point of rupture. In simple mechanical terms, rupture of an artery occurs when the local wall stress exceeds the local wall strength. It is therefore understandable that numerous studies have attempted to estimate the AAA wall stress and investigate the relationship between the AAA wall stress and AAA symptoms. MATERIALS AND METHODS: We conducted computational biomechanics analysis for 19 patients with AAA (a proportion of these patients were classified as symptomatic) to investigate whether the AAA wall stress fields (both the patterns and magnitude) correlate with the clinical definition of symptomatic and asymptomatic AAAs. For computation of AAA wall stress, we used a very efficient method recently presented by the Intelligent Systems for Medicine Laboratory. The Intelligent Systems for Medicine Laboratory's method uses geometry from computed tomography images and mean arterial pressure as the applied load. The method is embedded in the software platform BioPARR-Biomechanics based Prediction of Aneurysm Rupture Risk, freely available from http://bioparr.mech.uwa.edu.au/. The uniqueness of our stress computation approach is three-fold: i) the results are insensitive to unknown patient-specific mechanical properties of arterial wall tissue; ii) the residual stress is accounted for, according to Y.C. Fung's Uniform Stress Hypothesis; and iii) the analysis is automated and quick, making our approach compatible with clinical workflows. RESULTS: Symptomatic patients could not be identified from the plots (pattern) of AAA wall stress and stress magnitude. Although the largest stress was predicted for a patient who suffered from AAA symptoms, the three patients with the smallest stress were also symptomatic. CONCLUSIONS: The results demonstrate, contrary to the common view, that neither the wall stress magnitude nor the stress distribution appears to be associated with the presence of clinical symptoms.

Hypogastric Artery Stenting for Chronic Intermittent Spinal Cord Ischemia After Thoracic Endovascular Aortic Repair.

PURPOSE: To report a case of chronic intermittent spinal cord ischemia (SCI) after thoracic endovascular aortic repair (TEVAR) and its successful treatment using hypogastric artery stenting. CASE REPORT: A 79-year-old patient presented in May 2013 with a thoracic aortic aneurysm (TAA) and a contained rupture. He urgently underwent TEVAR that covered 274 mm of descending thoracic aorta without immediate postoperative signs of acute SCI. At 3-month follow-up, he reported repeating incidents of sudden lower extremity weakness leading to a fall with a humerus fracture. A neurological consultation revealed the tentative diagnosis of intermittent SCI caused by TEVAR and initially recommended a conservative approach. During the following year there was no clinical improvement of the symptoms. Computed tomography angiography showed a high-grade stenosis of the right hypogastric artery, which was stented in November 2014 to improve the collateral network of spinal cord perfusion. Following treatment, the patient had no further neurological symptoms; at 32 months after the reintervention, the imaging follow-up documented a patent stent and continued exclusion of the TAA. CONCLUSION: Intermittent neurological symptoms after TEVAR should be suspected as chronic intermittent SCI. The improvement of collateral networks of the spinal cord by revascularization of the hypogastric artery is a viable treatment option.