Open and Endovascular Management of Aortic Aneurysms

Survival and durability after endovascular aneurysm repair reflect era-related surgical judgement

OBJECTIVE

Abdominal aortic aneurysm management guidelines from the National Institute for Clinical Excellence in 2020, based heavily on randomized controlled trials in an early era of infrarenal endovascular aneurysm repair (EVAR), suggested that the long-term outcomes after EVAR jeopardize its use in elective abdominal aortic aneurysm repair. We hypothesized that, in a rapidly evolving surgical field, the era of aneurysm repair may have a significant influence on long-term patient outcomes.

METHODS

Using a single-center retrospective cohort design, we identified two EVAR cohorts, the early cohort (n = 166) who underwent EVAR from 2008 to 2010, and a contemporary late cohort (n = 129) from 2015 to 2017. We assessed patient preoperative demographics and era of repair against the primary outcomes of reinterventions, reintervention-free survival, and mortality, addressing their relationships to anatomic selection criteria, graft durability, endoleak, and aneurysm diameter to 5 years after the procedure.

RESULTS

Early cohort patients had decreased reintervention-free survival (early 80.1% vs late 93.3%) and decreased overall survival (early 71.3% vs late 81%) at 3 years and throughout follow-up. The preoperative anatomy judged suitable for EVAR in early cohort patients was more variable than for late cohort patients, including 104% larger proximal and 106% larger distal landing zone diameters, with a mean 11.6-mm shorter length infrarenal aortic and 13.3-mm shorter length iliac sealing zones in the early group. Early cohort patients had more complications during follow-up, including graft kinking and endoleaks, and 24.4% of early vs 8.5% of late patients underwent one or more reinterventions.

CONCLUSIONS

Although technical skill in EVAR implantation may not evolve significantly after a threshold of cases, surgical judgement, relating to anatomic selection and device sizing, requires feedback from long-term sequalae and significantly impacted EVAR outcomes by era. EVAR patients from an early repair era had significantly worse outcomes, with more complications, reinterventions, and a decrease in survival.

Outcomes of open and endovascular repair of Kommerell diverticulum

OBJECTIVES

Kommerell diverticulum (KD) is a rare congenital vascular anomaly often associated with an aberrant subclavian artery (ASCA). Definitive indications for intervention remain unclear. We present open and endovascular (EV) operative outcomes in a large contemporary series and propose a management algorithm.

METHODS

Between 2004 and 2020, 224 patients presented with ASCA and associated KD to our institution. Of the 43 (19.2%) patients who underwent operative repair, 31 (72.1%) had open surgical (OS) repair via thoracotomy and 12 (27.9%) had EV repair. Univariable and bivariable statistical analyses were conducted stratified by approach. The median follow-up time was 5.4 years (IQR, 2.9-9.7).

RESULTS

Patients in EV group were older (68 years vs 47 years, P < 0.001) and had larger aneurysms (base diameter 3.2 cm vs 21.5 cm, P = 0.007). All patients with dysphagia lusoria were treated with open surgery (n = 20). Asymptomatic patients with incidentally detected KD (50% vs 16.1%), those with chest or back pain (50% vs 19.4%) and patients who presented with an aortic emergency (25% vs 6.5%) were more likely to be treated endovascularly (P = 0.001). Carotid-to-subclavian bypass was used in 38 (88.4%) patients. There were no operative mortalities. In-hospital mortality was similar between groups (3.2% vs 16.7%, P = 0.121). Mid-term mortality was higher in the EV group [4 (33.8%) vs 0, P < 0.001]. There were 2 (15.4%) postoperative strokes in the EV group. There were no statistically significant differences in other postoperative complications or hospital length of stay between groups.

CONCLUSIONS

KD can be managed using open or EV approaches with low morbidity and mortality. Treatment strategy should depend on clinical presentation and patient factors.

ERA OF ENDOVASCULAR AORTIC ANEURYSM REPAIR IS LINKED TO PREOPERATIVE ANATOMIC SEVERITY AND PERIOPERATIVE PATIENT OUTCOMES

OBJECTIVE

Varying opinions on optimal elective and emergent surgical management of infrarenal AAAs are expressed by the most recent Society for Vascular Surgery (SVS), European Society for Vascular Surgery (ESVS), versus NICE (National Institutes for Health and Care Excellence, UK) guidelines. The NICE guidelines propose that open surgical repair (OSR) serve as the default treatment for infrarenal AAA. The rationale for this approach relied on data from the early era of endovascular aneurysm repair (EVAR), and are in contrast to the more balanced approaches of the SVS and ESVS. We hypothesize that significant differences in patient selection, management, and postoperative outcome are related to the era in which treatment was undertaken, contextualizing the outcomes reported in early era EVAR RCTs.

METHODS

Retrospectively, two cohorts representing all EVAR patients from "early", n= 167 (2008-2010) and "late" n=129 (2015-2017) periods at a single treating institution, were assembled. Primary outcomes of era-related changes in preoperative demographics, anatomy, and intraoperative events were assessed; anatomy was compared using the Society for Vascular Surgery Anatomic Severity Grading (ASG) system. These era-related differences were then placed in the context of early perioperative outcomes and at follow-up to one year.

RESULTS

Choice of surgical strategy differed by era, despite the same patient preoperative comorbidities between EVAR groups. Preoperative anatomic severity was significantly worse in the early cohort (p<.001), with adverse proximal and distal seal zone features (p<·001). Technical success was 16·2% higher in the late cohort, with significantly fewer type 1A/B endoleaks perioperatively (p<.001). In-hospital complications, driven by higher acute kidney injury and surgical site complications in the early cohort, resulted in a 16·5% difference between cohorts (p<0·05). At one year of follow-up, outcome differences persisted; late era patients had fewer 1A endoleaks, fewer graft complications, and better reintervention-free survival.

CONCLUSIONS

From a granular dataset of EVAR patients, we found an impact of EVAR repair era on early clinical outcome; late cohort infrarenal (IR) EVAR patients had less severe preoperative anatomy, and improved perioperative and follow-up outcomes to one year, suggesting that the results of early EVAR RCTs may no longer be generalizable to modern practice.

The role of the pedicle omental flap in ruptured abdominal aortic aneurysm: a case report and literature review

A ruptured infrarenal abdominal aortic aneurysm (rAAA) is associated with an in-hospital mortality rate of 40% and an overall mortality rate of 60–80%. Open surgical repair for rAAA remains the principal method of treatment when endovascular repair is not available. Graft infection occurs in 1–4% of patients at 5 years, with a high incidence following emergency treatment. Other graft-related complications include pseudoaneurysm, graft occlusion and aorto-enteric fistula. This case report describes a 66-year-old male patient that was admitted to hospital complaining of intense abdominal pain, low blood pressure and tachycardia. He was diagnosed with a rAAA and treated using segmental resection of the abdominal aorta followed by reconstruction with a synthetic Dacron prosthesis. A pedicle omental flap was wrapped around the prosthetic graft and it was also used to fill the retroperitoneal cavity in order to reduce the risk of graft-related complications. Computed tomography angiography after 6 months showed good integration of the aortic prosthetic graft and the viability of the omental flap. In our opinion, vascular surgeons should consider the pedicle omental flap when they perform open surgical repair for rAAA in order to reduce the incidence of graft-related complications.

[Graft-renal bypass surgery during intraoperative dissection of renal artery in a patient with high occlusion of the aorta]

Despite advances in the development of endovascular techniques of revascularization of renal arteries, in certain clinical cases still remains the need to perform extra-anatomic renal bypass grafting. To such instances belong complicated atherosclerotic aortic lesions, technical difficulties occurring during open revascularization of the aorta and its branches, as well as aneurysms of the juxtarenal portion of the abdominal aorta. Presented herein is a clinical case concerning a patient subjected to non-standard restoration of blood flow in the right renal artery after thromboendarterectomy from the juxtarenal aorta, performed from the left-sided extraperitoneal phrenolumbotomic approach and complicated by secondary dissection of the intima in the right renal artery.

[Endovascular and hybrid treatment of thoracic and thoracoabdominal aortic aneurysms and dissections]

The article deals with immediate and medium-term results of hybrid and endovascular treatment of 74 patients with various pathologies of the thoracic and thoracoabdominal aorta (31 with aneurysms, 43 with thoracic and thoracoabdominal aortic dissections). Elective and emergency interventions were performed in 49 and 25 patients, respectively. Endoprosthetic repair of the arch, descending thoracic and thoracoabdominal aorta was performed in 25 patients, hybrid operations in 47 subjects (open switch of brachiocephalic, visceral and renal arteries followed by aortic endoprosthetic repair - 37, endovascular methods of making a landing zone - 12). The duration of the follow-up period after discharge from hospital amounted to 24.9±16.3 months. The technical success level was 98.6%. The overall hospital mortality rate was 11% (n=8), elective - 4% (n=2), emergency - 24% (n=6). Eight patients underwent repeat interventions on the thoracic and thoracoabdominal aorta. The 5-year cumulative survival rate was 82.3%, with freedom from repeat interventions amounting to 51.3%. Hybrid operations on the arch and descending thoracic aorta are considered to be a relatively safe and effective method of treatment. Follow-up and timely treatment of remote complications after hybrid or endovascular operations are obligatory for improving the results.

Comparative evaluation of ballet-type and conventional stent graft configurations for endovascular aneurysm repair: A CFD analysis

PURPOSE:

Cross limb stent graft (SG) configuration technique for endovascular aneurysm repair (EVAR) is employed for splayed aortic bifurcations to avoid device kinking and smoothen cannulation. The present study investigates three types of stent graft (SG) configurations for endovascular aneurysm repair (EVAR) in abdominal aortic aneurysm. A computational fluid dynamic analysis was performed on the pulsatile non-Newtonian flow characteristics in three ideally modeled geometries of abdominal aortic (AA) SG configurations.

METHODS:

The three planar and crosslimb SG configurations were ideally modeled, namely, top-down nonballet-type, top-down ballet-type, and bottom-up nonballet-type configurations. In top-down SG configuration, most of the device is deployed in the main body in the vicinity of renal artery and the limbs are extended to the iliac artery. While in the bottom-up configuration, some of the SG device is deployed in the main body, the limbs are deployed in aortic bifurcation, and the extra stent graft of the main body is extended to the proximal aorta until the below of the renal artery. The effects of non-Newtonian pulsatile flow on the wall stresses and flow patterns of the three models were investigated and compared. Moreover, the average wall shear stress (AWSS), oscillatory shear stress index (OSI), absolute helicity, pressure distribution, graft displacement and flow visualization plots were analyzed.

RESULTS:

The top-down ballet-type showed less branch blockage effect than the top-down nonballet-type models. Furthermore, the top-down ballet-type configuration showed an increased tendency to sustain high WSS and higher helicity characteristics than that of the bottom-up and top-down non-ballet type configurations. However, displacement forces of the top-down ballet-type configuration were 40% and 9.6% higher than those of the bottom-up and top-down nonballet-type configurations, respectively.

CONCLUSIONS:

Some complications such as graft tearing, thrombus formation, limb disconnection during long term follow up periods might be relevant to hemodynamic characteristics according to the configurations of EVAR. Hence, the reported data required to be validated with the clinical results.

Mortality of major cardiovascular emergencies among patients admitted to hospitals on weekends as compared with weekdays in Taiwan

Background

Several studies have found a so-called weekend effect that patients admitted at the weekends had worse clinical outcomes than patients admitted at the weekdays. We performed this retrospective cohort study to explore the weekend effect in four major cardiovascular emergencies in Taiwan.

Methods

The Taiwan National Health Insurance (NHI) claims database between 2005 and 2015 was used. We extracted 3811 incident cases of ruptured aortic aneurysm, 184,769 incident cases of acute myocardial infarction, 492,127 incident cases of ischemic stroke, and 15,033 incident cases of pulmonary embolism from 9,529,049 patients having at least one record of hospitalization in the NHI claims database within 2006 ~ 2014. Patients were classified as weekends or weekdays admission groups. Dates of in-hospital mortality and one-year mortality were obtained from the Taiwan National Death Registry.

Results

We found no difference in in-hospital mortality between weekend group and weekday group in patients with ruptured aortic aneurysm (45.4% vs 45.3%, adjusted odds ratio [OR] 1.01, 95% confidence interval [CI] 0.87–1.17, p = 0.93), patients with acute myocardial infarction (15.8% vs 16.2%, adjusted OR 0.98, 95% CI 0.95–1.00, p = 0.10), patients with ischemic stroke (4.1% vs 4.2%, adjusted OR 0.99, 95% CI 0.96–1.03, p = 0.71), and patients with pulmonary embolism (14.6% vs 14.6%, adjusted OR 1.02, 95% CI 0.92–1.15, p = 0.66). The results remained for 1 year in all the four major cardiovascular emergencies.

Conclusions

We found no difference in either short-term or long-term mortality between patients admitted on weekends and patients admitted on weekdays in four major cardiovascular emergencies in Taiwan.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12913-021-06553-7.

Effects of Exercise Training on Vascular Markers of Disease Progression in Patients with Small Abdominal Aortic Aneurysms

BACKGROUND

Currently, no medical therapy is effective in limiting progression of small abdominal aortic aneurysms (AAA; ≤5.5 cm). Previously, we have demonstrated safety and efficacy of exercise training in patients with AAA. However, the impact of exercise training on vascular markers of AAA progression, such as lipid accumulation product and matrix metalloproteinase 9 (MMP-9, linked to destruction of aortic matrix), is unknown. The aim of this study was to assess the impact of exercise training on AAA diameter, lipid accumulation product, MMP-9, and other risk markers of vascular disease.

METHODS

In this randomized trial, complete data of 96 patients (male: n = 87, female: n = 9; exercise training (exercise) n = 42, usual care n = 54) were studied. Changes in AAA diameter, exercise capacity, lipid accumulation product (men = [waist circumference 65] × fasting triglycerides; women = [waist circumference -58] × triglycerides) and MMP-9 were performed.

RESULTS

The exercise group demonstrated a significant increase in maximal exercise time and estimated metabolic equivalent of tasks. Lipid accumulation product decreased in exercise and increased in usual care (P < .001 between groups); MMP-9 remained statistically unchanged in exercise, but increased significantly in usual care (P = .005; between groups P = .094). In both groups, there was a significant increase in transverse diameter, but no difference between groups; neither group assignment nor level of fitness correlated with AAA enlargement. No adverse clinical events occurred.

CONCLUSIONS

This is the first study to demonstrate that in AAA, exercise beneficially modifies lipid accumulation product and MMP-9, both markers of vascular disease, without inducing aneurysmal growth beyond what is otherwise observed during usual care.

Imaging Biological Pathways in Abdominal Aortic Aneurysms Using Positron Emission Tomography

[Figure: see text].

Ten-year single center experience in elective standard endovascular abdominal aortic aneurysm repair

BACKGROUND

Endovascular aneurysm repair (EVAR) has become the treatment of choice for abdominal aortic aneurysm (AAA), demonstrating excellent early outcomes. However, EVAR durability has been questioned in the long-term period. The aim of this study was to assess EVAR outcomes in terms of survival and freedom from re-intervention during a long-term period.

METHODS

All consecutive patients being treated, with elective standard EVAR, in a single tertiary center, were included between 2008 and 2018. Outcomes were defined as survival and freedom from re-intervention and were reported using Kaplan-Meyer lifetables. In subgroup analyses, sex, age (threshold at 65 and 80 years), neck diameter>28mm and type of fixation were also analyzed. Type of re-intervention and endoleak type I (ETIa) were also reported.

RESULTS

Five hundred and eight patients (94% males, mean age 72±7.3, mean AAA diameter 59±9mm) were included. The median follow-up was 3 years (range 0-10 years). The survival rate was 92.8% (SE 1.5%), 76.5% (SE 3.1%) and 41.6% (SE 6%), at 2, 5 and 10 years of follow-up, respectively. In total, 78 patients died; 8 deaths (8/75, 10%) were aneurysm related. In multivariate regression analysis, age (CI. 1.02-1.14; p=0.006) and ever tobacco use (CI. 1.02-6.12, P=0.045) were associated with the long-term mortality. Freedom from re-intervention was 96% (SE 1.1%), 93% (SE 1.8%), 85.5% (SE 5%) at 2, 5 and 9 years of follow-up. Limb occlusion was a common complication (n/n; 30% of re-intervention), particularly within the first 2 postoperative years. Six patients presented with rupture and were treated with open conversion. EVAR cases with supra-renal fixation graft presented lower rates of ETIa (CI. 76-87.27, P<0.001).

CONCLUSIONS

Elective standard EVAR is associated with good long-term survival showing low aneurysm-related mortality. Common risk factors such as advanced age and smoking are associated to higher mortality. The procedure presents low re-intervention rates, while limb occlusion is a complication presented within the first 2 postoperative years.

Splanchnic occlusive disease predicts for spinal cord injury after open descending thoracic and thoracoabdominal aneurysm repair

OBJECTIVE

In the present study, we sought to discern the effects of splanchnic occlusive disease (SOD; renal, superior mesenteric, and/or celiac axis arteries) on spinal cord injury (SCI; paraparesis or paraplegia) and major adverse events (MAE) after descending thoracic aneurysm (DTA) and thoracoabdominal aortic aneurysm (TAAA) open repair.

METHODS

Patients who had undergone DTA/TAAA repair at our institution were dichotomized according to the presence of SOD, which was investigated as a predictive factor of our primary (SCI) and secondary (operative mortality, myocardial infarction, stroke, tracheostomy, de novo dialysis, MAE, survival) endpoints. Risk adjustment used both propensity score matching and multivariable logistic regression.

RESULTS

From July 1997 to October 2019, 888 patients had undergone DTA/TAAA repair, of whom 19 were excluded from our analysis for missing data. SOD was absent in 712 patients and present in 157 patients. The patients with SOD had presented with a greater incidence of preoperative renal impairment (61 [38.9%] vs 175 [24.6%]; P < .01) and peripheral arterial disease (60 [38.2%] vs 162 [22.8%]; P < .01] and decreased left ventricular ejection fraction (45%; interquartile range, 10%; vs 50%; interquartile range, 4%; P < .01). The etiology of aortic disease was more frequently dissection in the SOD group (56.1% vs 43.7%) and more frequently nondissecting aneurysm in the non-SOD group (56.3% vs 43.9%; P < .01). Patients without SOD had presented with aneurysms more cranially located (DTA, 34.0% vs 7.6%; extent I TAAA, 44.0% vs 7.6%). In contrast, patients with SOD had presented with aneurysms more caudally located (extent II TAAA, 36.9% vs 8.6%; extent III TAAA, 30.6% vs 11.0%; extent IV TAAA, 17.2% vs 2.5%; P < .01). Propensity score matching led to 144 pairs, with SOD significantly associated with SCI (10 [6.9%] vs 2 [1.4%]; P = .03) and MAE (47 [32.6%] vs 26 [15%]; P < .01). Ten-year survival was reduced in those with SOD (31.5% vs 45.2%; P < .01). Conditional multivariable regression confirmed SOD to be a predictor of SCI in the matched sample (odds ratio, 6.60; P = .02).

CONCLUSIONS

Our results have shown that SOD is a significant predictor of SCI in patients undergoing open DTA/TAAA repair. The investigation of measures to prolong neuronal ischemia tolerance (eg, hypothermia) is warranted for such patients.

Characteristics and Prognosis of Abdominal or Thoracic Aortic Aneurysm Patients Admitted to Intensive Care Units After Surgical Treatment: A Multicenter Retrospective Observational Study

Objective

To investigate the characteristics and prognosis of abdominal or thoracic aortic aneurysm (AAA or TAA) patients admitted to intensive care unit (ICU) postoperatively.

Methods

Patients admitted to ICU postoperatively with a primary diagnosis of AAA or TAA were screened in the eICU Collaborative Research Database, which contained data from multiple ICUs throughout the continental United States in 2014 and 2015. Baseline characteristics and comorbidities and were investigated and factors associated with ICU mortality were explored using univariable logistic regression. Receiver operating characteristic (ROC) curve analysis was performed to evaluate the prognosis predictive performance of the widely used severity scoring system APACHE IVa.

Results

A total of 974 patients including 677 AAA and 297 TAA patients admitted to ICU postoperatively were included. Compared with TAA, AAA patients had a significantly higher median age (72 versus 64 years, P<0.001). 89.07% AAA and 84.51% TAA patients underwent elective surgery (P=0.046), 8.71% AAA and 31.99% TAA patients were with aortic dissection (P<0.001), and 10.19% AAA and 2.36% TAA patients suffered from rupture of aortic aneurysm (P<0.001). Hypertension requiring treatment was the most common comorbidity (57.31% for AAA and 61.95% for TAA). TAA patients had significantly higher ICU mortality (9.43% versus 2.36%, P<0.001) than AAA. Several factors were found to be significantly associated with ICU mortality, including urgent surgery, with aortic dissection, rupture of aortic aneurysm, TAA, and a higher APACHE IVa score on ICU admission. APACHE IVa showed a good predictive performance for ICU mortality with an area under the ROC curve of 0.9176 (95% CI 0.8789–0.9390).

Conclusion

The prognosis of aortic aneurysm patients admitted to ICU postoperatively is yet to improve, and factors associated with prognosis are mainly related to the condition itself. APACHE IVa can be used for prognosis prediction.

Thoracic aortic aneurysms in patients with heritable connective tissue disease

BACKGROUND

Patients with connective tissue diseases are at high lifetime risk of developing thoracic aortic aneurysms (TAAs) due to defects in extracellular matrix composition which compromise the structural integrity of the aortic wall. It is vital to identify and manage aneurysms early to prevent fatal complications such as dissection or rupture.

METHOD

This review synthesises information obtained from a thorough literature search regarding the pathophysiology of TAAs in those with heritable connective tissue diseases (HCTDs), the investigations for timely diagnosis and current operative strategies.

RESULTS

Major complications of open repair (OR) include pneumonia (32%), haemorrhage (31%) and tracheostomy (18%), with a minor risk of vocal cord paresis (9%). For thoracic endovascular aortic repair (TEVAR), high rates of endoleak were documented (38-66.6%). Reintervention rates for TEVAR are also high at 38-44%. Mortality rates were documented as 25% for open repair and vary from 14% to 44% for TEVAR.

CONCLUSION

OR remains the mainstay of surgical management. While TEVAR use is expanding, it remains the alternative choice due to concerns over endograft durability, limited long-term outcome data and the lack of high-quality evidence regarding its use in HCTD patients.

Management of Concealed Type IV Endoleak and Aortic Sac Hygroma by Prone ContrASt EnHancement Computed Tomography Angiography

BACKGROUND

Aortic sac hygroma and concealed endoleaks (EL) after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysm needs particular attention with aggressive management as they are associated with rapid sac expansion and rupture risk. However, they can be erroneously reported as type IV or V EL with supine computed tomography (CT) scans, leading to delay in management. Therefore, we describe a novel diagnostic technique, 'Prone contrASt enHanced computed tomography Angiography' (PASHA), to document concealed EL METHODS: We present eight case descriptions with continuous sac expansion after primary EVAR. Management began with diagnosis using the PASHA imaging technique. PASHA is a multiphase CTA positional technique for increasing the accuracy of detecting EL after EVAR. Furthermore, the PASHA imaging technique also guides whether the open or endovascular intervention could be used effectively to manage the sac expansion. In synchrony with the PASHA technique, "EVAR GORE SalvAge FAbric Technique" (ARAFAT) was to salvage previous EVAR.

RESULTS

The PASHA technique diagnosed all cases of type IIIb EL, as it enhanced the degree of contrast infiltration into the aortic sac when microleaks were present. ARAFAT was effectively used in five elderly patients. Another three had an open conversion; two with double breasting of the aortic sac and one EVAR explantation.

CONCLUSIONS

The PASHA protocol helped classify and localize the concealed EL (type IV, V), which were not appropriately diagnosed by supine CT protocols. PASHA and ARAFAT were used as a fully functioning protocol to overcome apparent challenges in accurate diagnosis and subsequent concealed EL management in high-risk patients.

Epidemiology and management of aortic disease: aortic aneurysms and acute aortic syndromes

The aorta is the 'greatest artery', through which oxygenated blood is delivered from the left ventricle to end organs with each cardiac cycle (200 million litres of blood transported in an average lifetime). The aorta can be affected by a wide spectrum of acute factors (such as cocaine use, weight lifting and trauma) and chronic acquired and/or genetic conditions (such as systemic arterial hypertension and phaeochromocytoma), which variously lead to increased aortic wall stress. The medial layer of the aorta can also be subject to abnormalities (such as Marfan syndrome, bicuspid aortic valve, inflammatory vasculitis, atherosclerosis and infections). Despite important advances in diagnostic and therapeutic interventions, data derived from registries and population-based studies highlight that the burden of aortic diseases remains high. Therefore, specific resources need to be allocated to design and implement preventive strategies (healthy lifestyles, modifications to cardiovascular risk factors, and educational and screening programmes) at individual and community levels. In this Review, we discuss the epidemiology, management and outcomes of the most common aortic diseases, namely, aortic aneurysms and acute aortic syndromes.

Modeling aortic diseases using induced pluripotent stem cells

Induced pluripotent stem cells (iPSCs) offer an effective platform for studies of human physiology and have revealed new possibilities for disease modeling at the cellular level. These cells also have the potential to be leveraged in the practice of precision medicine, including personalized drug testing. Aortic diseases result in significant morbidity and mortality and pose a global burden to healthcare. Their pathogenesis is mostly associated with functional alterations of vascular components, such as endothelial cells and vascular smooth muscle cells. Drugs that have been proven to be effective in animal models often fail to protect patients from adverse aortic events in clinical studies, provoking researchers to develop reliable in vitro models using human cells. In this review, we summarize the patient iPSC-derived aortic cells that have been utilized to model aortic diseases in vitro. In advanced models, hemodynamic factors, such as blood flow-induced shear stress and cyclic strain, have been added to the systems to replicate cellular microenvironments in the aortic wall. Examples of the utility of such factors in modeling various aortopathies, such as Marfan syndrome, Loeys-Dietz syndrome, and bicuspid aortic valve-related aortopathy, are also described. Overall, the iPSC-based in vitro cell models have shown the potential to promote the development and practice of precision medicine in the treatment of aortic diseases.

Postimplantation syndrome in endovascular aortic aneurysm repair - a systematic review

Postimplantation syndrome (PIS) following endovascular aortic aneurysm repair (EVAR) is a poorly understood phenomenon occurring in the early post-operative course. The underlying aetiology, risk factors, clinical sequalae, and treatment options, are largely unknown. The lack of any standardised diagnostic criteria limits current research in this field. The MEDLINE database was interrogated using a Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) search strategy. Five search terms were used; "postimplantation syndrome" AND "aneurysm", AND "infection", AND "complications", AND "biomarkers", AND "outcomes". 19 studies were included in the review process, reporting a 17.4%-39.0% incidence of PIS. IL-6 was the most commonly elevated biomarker in PIS vs. non-PIS patients. There was a higher incidence of PIS in patients who received polyester rather than expanded-polytetrafluoroethylene (ePTFE) grafts. There was a lower rate of type 2 endoleaks observed in patients who developed PIS. Early major adverse cardiovascular events (MACE) were higher in PIS patients, however there were no studies reporting long-term MACE. Length of stay was higher in PIS patients. Current data support the role of IL-6 as being key to the development of PIS following EVAR. Further work describing the effect that PIS has on long-term clinical outcomes is needed. Lack of standardised diagnostic criteria limit the reporting of PIS between centres, the criteria proposed by this review may resolve this.

Innovative textile structures designed to prevent type III endoleaks in endovascular stent-grafts

The damage caused to the fabric of endovascular stent-grafts most often occurs at the contact zones between the fabrics where they are attached to the apices of Z-shaped stents as a result of normal physiologic pulsatile movement within angulated vessels in vivo. Although design improvements were made over the years, the risks were not fully eliminated even with the newer M-shaped stent reconfiguration. In this study, we proposed to create and manufacture a novel fabric for stent-grafts with specifically designed reinforced zones to enhance resistance to fabric abrasion. These reinforced zones are set at the vicinity of the apices of the Z-shaped stents and between two adjacent Z-shaped stents where folding and pleating are commonly observed to occur in angulated vessels. Three innovative weaving structures with two different types of yarns and two controls were designed and prepared. Two commonly used commercial devices supported, respectively, with ringed stents, and Z-shaped stents were selected as the references for comparison. Textile structures including thickness, water permeability, mechanical properties, (more specifically tensile and bursting stress, as well as fatigue simulation) were tested on all fabrics. Compared to commercially available plain weaves, the fabrics with locally reinforced zones showed improved mechanical characteristics and fatigue resistant properties. A fabric designed with specifically reinforced zones has now clearly been shown to effectively reduce the abrasion caused by the apices of Z-shaped stents. However, further optimization may still be possible.

Open Surgical Repair of Abdominal Aortic Aneurysms Maintains a Pivotal Role in the Endovascular Era

Since the advent of endovascular aortic repair (EVAR) nearly three decades ago, there has been a paradigm shift in the treatment of the abdominal aortic aneurysm (AAA) to favor EVAR due to its reduced operative mortality, less invasive nature, and faster recovery times. However, more recently there has been an accumulation of data from large meta-analyses and randomized clinical trials revealing that EVAR has no survival benefit after approximately 2 years and is associated with substantially higher rates of reintervention and aneurysm rupture in the long term. These findings call into question the durability of EVAR compared with open aortic repair and emphasize the need for surgeons to remain competent with open aortic surgery in the modern era. This article will provide comprehensive review of a large body of literature comparing endovascular repair to open aortic surgery for the management of AAAs, and it will offer an overview of the open surgical repair technique for AAAs.

Conceptual Framework Development for a Double-Walled Aortic Stent-Graft to Manage Blood Pressure

A double-walled stent-graft (DWSG) design with a compressible gas layer was conceived with the goal of treating hypertension in patients receiving an aortic stent-graft. Early prototypes were developed to evaluate the design concept through static measurements from a finite element (FE) model and quasi-static inflation experiments, and through dynamic measurements from an in vitro flow loop and the three-element Windkessel model. The amount of gas in the gas layer and the properties of the flexible inner wall were the primary variables evaluated in this study. Properties of the inner wall had minimal effect on DWSG behavior, but increased gas charge led to increased fluid capacitance and larger reduction in peak and pulse pressures. In the flow loop, placement of the DWSG decreased pulse pressure by over 20% compared to a rigid stent-graft. Capacitance measurements were consistent across all methods, with the maximum capacitance estimated at 0.07 mL/mmHg for the largest gas charge in the 15 cm long prototype. Windkessel model predictions for in vivo performance of a DWSG placed in the aorta of a hypertensive patient showed pulse pressure reduction of 14% compared to a rigid stent-graft case, but pressures never returned to unstented values. These results indicate that the DWSG design has potential to be developed into a new treatment for hypertensive patients requiring an aortic intervention.

A Late Post-EVAR Rupture in a 102-Year-Old Patient Related to a Type II Endoleak

PURPOSE

Endovascular abdominal aortic aneurysm repair (EVAR) is progressively being applied in the elderly population. Type II endoleaks are common and mostly benign, but they are related to more aneurysm sac expansion after EVAR. They may lead to rupture in <1% of cases. We present a case of a centenarian with a post-EVAR rupture, related to type II endoleak, and discuss the use of EVAR on the management of this type of endoleak in an extremely old patient.

CASE PRESENTATION

A 102-year-old man with a history of EVAR 12 years earlier, presented to the emergency department with a drop of consciousness. A computed tomography revealed a ruptured abdominal aortic aneurysm. Angiography showed a type II endoleak related to patent lumbar arteries deriving from collateral branches of the right internal iliac artery. Embolization was not successful and subsequently the ostium of the iliolumbar artery was overstented, obliterating the feeding branch. The postoperative course was complicated by a deterioration of chronic obstructive pulmonary disease and patient was discharged home on the seventh postprocedural day; nonetheless, he died on postoperative day sixteenth due to respiratory complications.

CONCLUSION

Complications following EVAR are a real threat and emphasize the need for follow-up. The current case report shows that age per se should not be a contraindication for EVAR nor for follow-up. Also, late ruptures due to type II endoleaks could be treated in the very elderly population although larger series are required for robust conclusions.

Open vs. endovascular thoracoabdominal aortic aneurysm repair: tale of the tape

Open surgical repair persists as the gold-standard operation for thoracoabdominal aortic aneurysm; however, endovascular repair has become commonplace. Technical considerations in thoracoabdominal aortic aneurysm treatment are particularly complex, insofar as it involves critical branching arteries feeding the visceral organs. Newer, low-profile devices make total endovascular thoracoabdominal aortic aneurysm repair more feasible and, thus, appealing. For younger and low-risk patients, the choice between open and endovascular therapy remains controversial. Despite the advantages of a minimally invasive procedure, data suggest that endovascular aortic repair incurs a greater risk of spinal cord deficit, and the durability of endovascular aortic repair remains unclear. It is difficult to compare outcomes between endovascular and open thoracoabdominal aortic aneurysm repair, primarily because of the current investigational status of endovascular devices, the variety of approaches to endovascular repair, differing patient populations, lack of prospective randomized studies, and minimal medium- and long-tern follow-up data on endovascular repair. When deciding between open and endovascular approaches, one should consider which is more suitable for each patient. Older patients generally benefit from a less invasive approach. Open repair should be considered for young patients and those with heritable thoracic aortic disease. Infection and fistulae are best treated by open repair, although endovascular intervention as a lifesaving bridge to definitive repair has evolved to become a critical component of initial treatment. It is crucial to have technical expertise in both open and endovascular procedures to provide the best aortic repair for the patient. This may require dedicated aortic programs at tertiary institutions.

A Novel Hybrid Drug Delivery System for Treatment of Aortic Aneurysms

Ongoing aortic wall degeneration and subsequent aneurysm exclusion failure are major concerns after an endovascular aneurysm repair with a stent-graft. An ideal solution would be a drug therapy that targets the aortic wall and inhibits wall degeneration. Here, we described a novel drug delivery system, which allowed repetitively charging a graft with therapeutic drugs and releasing them to the aortic wall in vivo. The system was composed of a targeted graft, which was labeled with a small target molecule, and the target-recognizing nanocarrier, which contained suitable drugs. We developed the targeted graft by decorating a biotinylated polyester graft with neutravidin. We created the target-recognizing nanocarrier by conjugating drug-containing liposomes with biotinylated bio-nanocapsules. We successfully demonstrated that the target-recognizing nanocarriers could bind to the targeted graft, both in vitro and in blood vessels of live mice. Moreover, the drug released from our drug delivery system reduced the expression of matrix metalloproteinase-9 in mouse aortas. Thus, this hybrid system represents a first step toward an adjuvant therapy that might improve the long-term outcome of endovascular aneurysm repair.

Factors Affecting Outcomes in Acute Type A Aortic Dissection: A Systematic Review

Acute type A aortic dissection is a clinical emergency and is associated with significant morbidity and mortality rates if not managed promptly in specialised and high-volume centres. The mortality rate is increased by 1% for each hour delay in management; however, with advancement in clinical practice, diagnostic imaging and clinician awareness, this has been dramatically reduced to below 30% in most international centres. Not only timing of recognition of the pathology, but also other factors can significantly affect outcomes of such critical pathology. This includes, but is not limited to, age, extent of the pathology, existence of connective tissue disorders, hypertension, diabetes mellitus and surgeon experience. This narrative review will focus on current clinical practice and the evidence behind optimising each factor to minimise adverse outcomes in such high-risk cohort.

Surgical treatment patterns and clinical outcomes of patients treated for expanding aneurysm sacs with type II endoleaks after endovascular aneurysm repair

OBJECTIVE

Persistent type II endoleaks (T2ELs) after endovascular aneurysm repair (EVAR) with sac growth have been associated with adverse events, including rupture. Whereas intervention in the presence of aneurysm growth has become an accepted treatment paradigm for T2ELs, the efficacy and clinical success of such interventions remain unclear. Therefore, we examined the treatment patterns and clinical outcomes of patients undergoing T2EL interventions after EVAR.

METHODS

We performed a retrospective review of all patients treated for expanding aneurysm sacs with T2ELs after EVAR at an academic medical center between 2006 and 2017. The primary outcomes assessed were need for repeated intervention; intervention types; and achievement of clinical success, defined as stable aneurysm sac size on computed tomography angiography after treatment.

RESULTS

Fifty-six patients underwent 119 interventions, of which 107 (90%) were technically successful. The median time from EVAR to index T2EL procedure was 37 months (interquartile range, 17-56 months), and the median follow-up time from first T2EL procedure was 27 months (interquartile range, 10-51 months). The most common index procedure was transarterial lumbar embolization (64%), followed by transarterial inferior mesenteric artery (20%), transcaval (14%), and translumbar embolization (1.8%). Thirty-three (59%) patients required further procedures for persistent aneurysm sac expansion. For subsequent T2EL interventions, the most common endovascular procedure was transarterial lumbar embolization (21%), followed by transcaval (21%), translumbar (11%), and transarterial inferior mesenteric artery embolization (8.6%). Twelve patients (21%) were found to have loss of proximal or distal seal on subsequent imaging and required graft extensions to stabilize aneurysm sac size. Ten patients (18%) ultimately underwent graft explantation or sacotomy with oversewing of the endoleak source. Freedom from any endoleak-related reintervention was 57% at 1 year and 36% at 3 years. Freedom from open treatment was 93% at 1 year and 82% at 3 years. Of the 44 patients with ≥6-month follow-up, 39 (89%) achieved clinical success. However, only 11 patients (25%) achieved clinical success without any further reintervention, and 29 patients (66%) achieved clinical success without open treatment.

CONCLUSIONS

Despite high technical success, endoleak recurrence after T2EL treatment is common, and multiple interventions are often needed to stabilize aneurysm sac size in patients diagnosed with T2EL-associated sac growth. Notably, one in five patients treated for T2ELs was discovered, on further evaluation, to have proximal or distal seal zone loss that necessitated repair to achieve sac stability. Thus, thorough assessment of all endoleak types should be performed in patients with T2ELs associated with sac growth before T2EL treatment to ensure appropriate care and to minimize ineffective interventions.

Spinal cord injury after open and endovascular repair of descending thoracic and thoracoabdominal aortic aneurysms: A meta-analysis

OBJECTIVE

An inclusive contemporary analysis of spinal cord injury (SCI) rates in patients undergoing aneurysm repair and the factors associated with complications has not been performed.

METHODS

Following a systematic literature search, studies from 2008 to 2018 on repair of descending thoracic aneurysm (DTA) and thoracoabdominal aortic aneurysm (TAAA) were pooled in a meta-analysis performed using the generic inverse variance method. The primary outcome was permanent SCI. Secondary outcomes were temporary SCI, operative mortality, long-term mortality, postoperative stroke, and cerebrospinal fluid (CSF) drain-related complications.

RESULTS

One-hundred sixty-nine studies (22,634 patients) were included. The pooled rate of permanent SCI was 4.5% (95% confidence interval [CI], 3.8-5.4); 3.5% (95% CI, 1.8-6.7) for DTA and 7.6% (96% CI, 6.2-9.3) for TAAA repair (P for subgroups = .02), 5.7% (95% CI, 4.3-7.5) for open repair and 3.9% (95% CI, 3.1-4.8) for endovascular repair (P for subgroups = .03). Rates for Crawford extents I, II, III, IV, and V aneurysms were 4.0% (95% CI, 3.0-5.0), 15.0% (95% CI, 10.0-22.0), 7.0% (95% CI, 6.0-9.0), 2.0% (95% CI, 2.0-4.0), and 7.0% (95% CI, 2.0-23.0) respectively (P for subgroups <.001). The pooled rates for operative mortality, late mortality at a mean follow-up of 5.0 years, stroke, and temporary SCI were 7.4% (95% CI, 6.1-9.4), 1.0% (95% CI, 0.0-1.0), 4.2% (95% CI, 3.6-4.8), and 3.7% (95% CI, 3.0-4.6), respectively. The pooled rates for severe, moderate, and minor CSF-drain related complications were 5.1% (95% CI, 2.23-11.1), 4.1% (95% CI, 0.6-22.0), and 3.6% (95% CI, 1.2-8.0) respectively.

CONCLUSIONS

Despite improvement, both open and endovascular aneurysm repair remain associated with a substantial risk of permanent SCI. The risk is greater for TAAA repair, especially extent II, III, and V.

Chemical stabilization of the extracellular matrix attenuates growth of experimentally induced abdominal aorta aneurysms in a large animal model

Objective

The goal of the present study was to test the safety and efficacy of chemical stabilization of the arterial extracellular matrix as a novel nonoperative treatment of abdominal aortic aneurysms (AAAs) in a clinically relevant large animal model.

Methods

To achieve matrix stabilization, we used 1,2,3,4,6-pentagalloylglucose (PGG), a noncytotoxic polyphenolic agent capable of binding to and stabilizing elastin and collagen against the action of degrading enzymes. We first optimized the therapeutic PGG formulation and time of exposure by in vitro testing on porcine aortas using phenol histologic staining with iron chloride, elastic recoil assays, and PGG quantification as a function of tissue thickness. We then induced AAAs in 16 swine using sequential balloon angioplasty and elastase/collagenase and calcium chloride treatment of the infrarenal segment. We monitored AAA induction and development using digital subtraction angiography. At 2 weeks after induction, after the AAAs had reached ∼66% arterial expansion, the swine were randomly assigned to 2 groups. In the treatment group, we delivered PGG to the aneurysmal aorta endoluminally using a weeping balloon and evaluated the AAA diameters using digital subtraction angiography for another 10 weeks. The control swine did not receive any treatment. For the safety evaluation, we collected blood and performed comprehensive metabolic panels and complete blood counts every 2 to 3 weeks for all the animals. The swine were routinely monitored for neurologic and physical attributes such as behavior, inactivity, alertness, appetite, discomfort, and weight gain. After euthanasia and full necropsy, we analyzed the AAA tissue samples for PGG content, elastic recoil, and histologic features.

Results

In vitro, a single 2.5-minute intraluminal delivery of 0.3% PGG to the swine aorta was sufficient for PGG to diffuse through the entire thickness of the porcine arterial tissues and to bind with high affinity to the elastic lamellae, as seen by positive iron chloride staining, a reduction of elastic recoil, and an increase in PGG content. In vivo, the control swine AAA tissues were thickened and showed the typical aspects of AAA, including chronic inflammation, adventitial reactivity, smooth muscle cell proliferation, elastic lamellae degradation, and medial and adventitial calcification. Similar aspects were noted in the PGG-treated arteries, except for the lack of calcification and an apparent diminished hyperplasia. PGG treatment was effective in reducing AAA expansion and reversing the process of AAA dilation by reducing the aortic diameters to ≤30% by week 12 (P < .05). PGG was specifically localized to the aneurysmal segments as seen by histologic examination, the reduction of elastic recoil, and an increase in PGG content. PGG treatment did not affect the swine's neurologic or physical attributes, weight, blood chemistry, blood cells, or functionality of remote organs. The control, untreated swine exhibited progressive increases in AAA diameters up to a mean value of 104%.

Conclusions

Localized delivery of PGG to the aneurysmal aorta attenuated AAA growth and reversed the course of the disease in the swine AAA model. Such specificity for diseased tissue is unprecedented in nonoperative AAA treatment. This novel paradigm-shifting approach has the potential to revolutionize AAA management and save thousands of lives.

Abdominal aorta aneurysm (AAA) is an asymptomatic chronic degenerative disease characterized by localized dilatation of the arterial wall caused by elastin and collagen degradation by proteases. We found that local delivery of 1,2,3,4,6-pentagalloylglucose (PGG) to a developing AAA in a swine animal model safely and effectively stabilized the vascular matrix, reduced AAA expansion, and promoted healing and AAA diameter reduction by limiting tissue degeneration. PGG is a noncytotoxic agent capable of rapid diffusion through arterial tissue and irreversible binding to elastin and collagen. PGG-mediated chemical stabilization of the aortic matrix could be used for safe nonoperative AAA management.

Endovascular Abdominal Aortic Aneurysm Repair

Most abdominal aortic aneurysms are treated with endovascular repair (EVAR) in current practice. EVAR has lower periprocedural mortality and morbidity than open surgical repair. Aneurysm neck morphology, iliac anatomy, and access vessel anatomy need careful assessment for the successful performance of EVAR. Regular and long-term follow-up with imaging is mandatory after EVAR, and patients who are less likely to comply are less favorable EVAR candidates. Endoleaks are the most frequent complication of EVAR. Most can be managed with transcatheter or endovascular means. Evolving technology and techniques are allowing more patients to be treated with EVAR with better long-term outcomes.

Impact of left ventricular ejection fraction on the outcomes of open repair of descending thoracic and thoracoabdominal aneurysms

OBJECTIVE

To discern the impact of depressed left ventricular ejection fraction (LVEF) on the outcomes of open descending thoracic aneurysm (DTA) and thoracoabdominal aneurysms (TAAA) repair.

METHODS

Restricted cubic spline analysis was used to identify a threshold of LVEF, which corresponded to an increase in operative mortality and major adverse events (MAE: operative death, myocardial infarction, stroke, spinal cord injury, need for tracheostomy or dialysis). Logistic and Cox regression were performed to identify independent predictors of MAE, operative mortality, and survival.

RESULTS

DTA/TAAA repair was performed in 833 patients between 1997 and 2018. Restricted cubic spline analysis showed that patients with LVEF <40% (n = 66) had an increased risk of MAE (odds ratio [OR], 2.17; 95% confidence interval [CI], 1.22-3.87; P < .01) and operative mortality (OR, 2.72; 95% CI, 1.21-6.12; P = .02) compared with the group with LVEF ≥40% (n = 767). The group with LVEF <40% had a worse preoperative profile (eg, coronary revascularization, 48.5% vs 17.3% [P < .01]; valvular disease, 82.8% vs 49.39% [P < .01]; renal insufficiency, 45.5% vs 26.1% [P < .01]; respiratory insufficiency, 36.4% vs 21.2% [P = .01]) and worse long-term survival (35.5% vs 44.7% at 10 years; P = .01). Nonetheless, on multivariate regression, depressed LVEF was not an independent predictor of operative mortality, MAE, or survival.

CONCLUSIONS

LVEF is not an independent predictor of adverse events in surgery for DTA.