Aortic Branch Vessels Research Articles

The incidence and effect of noncylindrical neck morphology on outcomes after endovascular aortic aneurysm repair in the Global Registry for Endovascular Aortic Treatment

BackgroundThe Gore Global Registry for Endovascular Aortic Treatment (GREAT) was designed to evaluate real-world outcomes after treatment with Gore aortic endografts used in a real-world, global setting. We retrospectively analyzed the GREAT data to evaluate the incidence and effects of noncylindrical neck anatomy in patients undergoing endovascular aortic aneurysm repair. MethodsThe present analysis included patients with data in the GREAT who had been treated with the EXCLUDER endograft from August 2010 to October 2016. A noncylindrical neck was defined when the proximal aortic landing zone diameter had changed ≥2 mm over the first 15 mm of the proximal landing zone, indicating a tapered, conical, or hourglass morphology. Cox multivariate regression analyses were performed for any reintervention (including reinterventions on aortic branch vessels), device-related reinterventions, and reintervention specifically for endoleak. Independent binary (cylindrical vs noncylindrical necks) and continuous (percentage of neck diameter change) variables were assessed. The abdominal aortic aneurysm (AAA) diameter, proximal neck length, maximal infrarenal neck angle, gender, and use of aortic extender cuffs were also assessed. ResultsOf 3077 GREAT patients with available proximal aortic landing zone diameter measurements available, 1765 were found to have cylindrical necks and 1312 had noncylindrical necks. The noncylindrical neck cohort had a significantly greater proportion of women (17.4% vs 12.6%; P < .001) and more severe infrarenal angulation (33.8° vs 28.4°; P < .001). A total 14.7% of noncylindrical neck patients and 11.2% cylindrical neck patients underwent implantation outside of the EXCLUDER instructions for use regarding the anatomic inclusion criteria (P = .004). The procedural characteristics were similar between the two cohorts; however, noncylindrical neck patients required significantly more aortic extender cuffs (P = .004). The average follow-up was 21.2 ± 17.5 months and 17.8 ± 15.8 months for the cylindrical and noncylindrical cohorts, respectively (P < .001). The Cox multivariate regression models demonstrated female gender and maximum AAA diameter were significant risk factors for subsequent reintervention (overall, device-related, and endoleak-specific). Women were 2.2 times as likely to require device-related intervention during the follow-up period compared with men (P < .001). Neck shape morphology was not a significant predictor, except for device-related intervention, for which cylindrical necks (binary definition) resulted in a slightly elevated risk (1.5 times; P = .03). ConclusionsNoncylindrical neck morphology was more common in women and was associated with an increased use of aortic extender cuffs but did not increase the risk of intervention. Female gender and AAA diameter were associated with an increased need for reintervention.

IP005. Preoperative Aneurysmal Thrombus Volume and Patency of Aortic Branch Vessels Are Inversely Correlated in Abdominal Aortic Aneurysm

IP005. Preoperative Aneurysmal Thrombus Volume and Patency of Aortic Branch Vessels Are Inversely Correlated in Abdominal Aortic Aneurysm

Natural History of Aneurysmal Aortic Arch Branch Vessels in a Single Tertiary Referral Center

Little is known about the natural history and management of aneurysmal aortic arch branch vessels (AARBVs). The objectives of this study were to assess the natural history of AARBVs and the AARBV’s risk of rupture and to examine the outcomes of operative intervention. A retrospective review of the Yale radiologic database from 1999 to 2016 was performed. Only those patients with AARBV and a computed tomography scan were selected for review. Patient demographics, aneurysm characteristics, management, and follow-up information were collected. There were 111 patients with 153 AARBVs identified; 79 were male (71%), with mean age of 70 years (range, 17-93 years). There were 65 brachiocephalic, 51 left subclavian, 33 right subclavian, and 4 common carotid artery aneurysms. On computed tomography, 68 (61%) had aortic aneurysms, 32 (29%) bovine arch, and 8 (7%) aortic dissections. Most were asymptomatic (105 [95%]); four had arm pain and one had chest pain, shortness of breath, and dysphagia, respectively. One patient presented with a ruptured brachiocephalic pseudoaneurysm (size, 6.5 cm). Nineteen (17%) patients underwent operative repair (OR); 92 (83%) were followed up with cross-sectional imaging (NOR). The overall mean vessel diameter was 2.22 ± 0.96 cm. The diameter of OR and NOR was 3.94 ± 1.61 cm and 1.97 ± 0.46 cm, respectively (P < .00001). OR included 13 bypasses, 5 stent grafts, and 1 resection without reconstruction. Two patients developed postoperative hemorrhage requiring re-exploration. One patient required pseudoaneurysm repair 20 years after index operation. Mean follow-up was 52 ± 51 months for NOR without any ruptures. Four patients underwent elective repair of AARBV because of either growth or other aortic operation. The growth rate was 0.04 ± 0.10 cm/y. On multivariable regression analysis, age (P = .011), the presence of ascending (P = .011) or descending aortic aneurysms (P =.005), and a left subclavian artery aneurysm (P = .038) were associated with higher growth rates, whereas height was associated with a lower growth rate (P = .0005). Few patients with AARBVs require an operation. Operative intervention is safe and has a low index of complications. In the presence of other aortic abnormalities, open repair would be favored. When feasible, an endovascular option can be pursued. Given that we observed no true AARBV rupture, patients can be observed safely with imaging, accepting a growth rate of 0.04 ± 0.10 cm/y.

A novel anatomic severity grading score for acute Type B aortic dissections and correlation to aortic reinterventions after thoracic endovascular aortic repair

BackgroundWe introduce a novel preoperative anatomic severity grading system for acute type B aortic dissections and validate the system in a cohort of patients who underwent thoracic endovascular aortic repair.MethodsWe identified a cohort of patients who received thoracic endovascular aortic repair (TEVAR) for acute type B aortic dissection from 2008 to 2014. We developed an anatomic severity grading score (ASG) to measure attributes of aortic anatomy that we hypothesized may affect difficulty or durability of repair. Measurements were made using computed tomography angiography images and based on hypothesized severity, giving a potential score range of 0-38.ResultsWe analyzed the computed tomography angiography images on a cohort of 30 patients with acute type B aortic dissection who underwent TEVAR. We created an area under the receiver operating characteristic curve (AUROC) using anatomic severity grading to predict aortic-related reinterventions. The AUROC was 0.72 (95% CI 0.39 to 1.1). Guided by the AUROC, we divided patients into two groups: a low-score group with anatomic severity grading scores <23 (n = 22), and a high-score group with scores ≥23 (n = 8). With this cutoff, anatomic severity grading exhibited 80% sensitivity and 84% specificity in predicting aortic-related reinterventions, with reinterventions in 50% of high-score patients and 4.5% of low-score patients (P = 0.011). The high score group also had significantly greater blood loss (200 vs 100 mL, P = 0.038), fluoroscopy time (36.0 vs 16.6 min; P = 0.022), and a trend for increased procedure time (164 vs 95 min; P = 0.083) than the low-risk group. Kaplan-Meier analysis revealed that the high-score group had a significantly decreased freedom from aortic-related reinterventions than the low-score group (38% vs 100% at 12-month followup; log rank P = 0.001).ConclusionsA preoperative anatomic severity grading score for acute type B aortic dissections consists of analysis of the proximal landing zone, curvature and tortuosity of the aorta, dissection anatomy, aortic branch vessel anatomy, and supraceliac aorta anatomy. Anatomic severity grading scores ≥23 are an excellent predictor of aortic-related reinterventions.

Management of the vertebral artery during thoracic endovascular aortic repair with coverage of the left subclavian artery

The application of thoracic endovascular aortic repair (TEVAR), a minimally invasive operation, in the aortic arch has been a challenge of cardiovascular surgery in recent years. This study aimed to investigate management of the vertebral artery with coverage of the left subclavian artery (LSA) during TEVAR. From January 2007 to September 2014 in the Department of Cardiothoracic Surgery at Wuhan General Hospital of Guangzhou Military Region, 160 patients underwent LSA closure or partial coverage during TEVAR of an aortic lesion near the LSA. The vertebral artery treatment, the reason for the surgical approach selection, and the prognosis were analyzed. In 94 patients with partial LSA coverage during TEVAR, no treatment was provided for the vertebral arteries, revealing blood flow of the left vertebral artery forward into the skull after surgery. For 66 patients with full LSA coverage (closure) during TEVAR, right carotid artery-left common carotid artery bypass surgery was performed before TEVAR in ten patients, without any treatment for the vertebral artery, showing reverse blood flow of the left vertebral artery after surgery. Left common carotid artery-LSA bypass surgery was performed before TEVAR in four patients; right common carotid artery-left common carotid artery-LSA bypass surgery was performed before TEVAR in three cases, and 6 out of these 7 patients underwent proximal LSA ligation, showing no obvious blood flow in the left vertebral artery. The closure of the LSA aortic arch opening using an occluder was performed in one patient, preserving the forward blood flow in the left vertebral artery. Among the 160 patients in this study, postoperative recurrent laryngeal nerve injury occurred in one patient after right common carotid artery-left common carotid artery-LSA bypass surgery, and the remaining 159 patients had no significant severe complications or death within 1 postoperative month. Appropriate management of the aortic arch branch vessels may expand the application of TEVAR to the aortic arch and reduce complications, especially for high-risk patients who have a difficult time tolerating thoracotomy.

Acute retrograde type A aortic dissection: morphologic analysis and clinical implications

BackgroundThis study compares the morphology and outcomes of acute retrograde type A dissections (RTADs) with acute antegrade type A dissections (ATADs), and acute type B dissections. Materials and methodsFrom 2000 to 2016, there were 12 acute RTADs, 96 ATADs, and 92 type B dissections with available imaging. Dissections were characterized using computerized tomography angiography images. We examined clinical features, tear characteristics, and various morphologic measurements. ResultsCompared with acute type B dissections, RTAD primary tears were more common in the distal arch (75% versus 43%, P = 0.04), and the false-to-true lumen contrast intensity ratio at the mid-descending thoracic aorta was lower (0.46 versus 0.71, P = 0.020). RTAD had less false lumen decompression because there were fewer aortic branch vessels distal to the subclavian that were perfused through the false lumen (0.40 versus 2.19, P < 0.001). Compared with ATAD, RTAD had less root involvement where root true-to-total lumen area ratio was higher (0.88 versus 0.76, P = 0.081). Furthermore, RTAD had a lower false-to-true lumen contrast intensity ratio at the root (0.25 versus 0.57, P < 0.05), ascending aorta (0.25 versus 0.72, P < 0.001), and proximal arch (0.39 versus 0.67, P < 0.05). RTAD were more likely to undergo aortic valve resuspension (100% versus 74%, P = 0.044). ConclusionsRTAD tends to occur when primary tears occur in close proximity to the aortic arch and when false lumen decompression through the distal aortic branches are less effective. Compared with ATAD, RTAD has less root involvement, and successful aortic valve resuspension is more likely.

Imaging of the Postsurgical Thoracic Aorta: A State-of-the-Art Review.

Techniques for repair of the aorta currently include open and endovascular methods, hybrid approaches, minimally-invasive techniques, and aortic branch vessel reimplantation or bypass. Collaboration among radiologists and vascular and cardiothoracic surgeons is essential. An awareness of the various surgical techniques, expected postoperative appearance, and potential complications is essential for radiologists. This review will cover the postoperative appearance of the thoracic aorta with a focus on the ascending aorta. The value of three-dimensional image evaluation will also be emphasized.

Congenital Variants and Anomalies of the Aortic Arch.

Congenital variants and anomalies of the aortic arch are important to recognize as they may be associated with vascular rings, congenital heart disease, and chromosomal abnormalities, and can have important implications for prognosis and management. The purpose of this article is to review cross-sectional imaging techniques used in the evaluation of the aortic arch, describe the embryology and anatomy of the aortic arch system, discuss aortic arch variants and anomalies, and review other malformations of the aortic arch, including interrupted aortic arch, hypoplastic aortic arch, and aortic coarctation. Aortic arch variants and anomalies will be reviewed in the context of a theoretical double aortic arch system. Arch anomalies can be associated with symptoms, such as dysphagia lusoria in the setting of left aortic arch with aberrant right subclavian artery. Arch variants that form a vascular ring, such as double aortic arch, can result in respiratory distress due to tracheal compression. Certain arch anomalies are strongly associated with congenital heart disease, including right aortic arch with mirror image branching. Other malformations of the aortic arch have important associations, such as type B interrupted aortic arch, which is associated with a locus 22q11.2 microdeletion. Noninvasive imaging at CT angiography and MR angiography allows for comprehensive evaluation of the aortic arch and branch vessels in relation to surrounding structures. Familiarity with the spectrum and imaging appearances of aortic arch variants, anomalies, and malformations is essential for accurate diagnosis and classification and to guide management. Online supplemental material is available for this article. ©RSNA, 2016.

RS17. STABLE II Clinical Trial on Endovascular Treatment of Acute, Complicated Type B Aortic Dissection With a Composite Device Design

This study evaluated the safety and effectiveness of a composite device design (covered stent graft + bare metal stent) for the treatment of patients with acute, complicated type B aortic dissection (cTBAD) presenting with aortic rupture and/or branch vessel malperfusion. In this prospective, nonrandomized, multicenter study, 73 patients (66% male; mean age, 61 years) were enrolled between August 2012 and January 2015 at institutions in the U.S. and Japan. The primary safety end point was the rate of freedom from major adverse events (MAEs) at 30 days, and the primary effectiveness end point was the rate of survival at 30 days. This abstract reports study data as of January 2016, with available follow-up examinations in 97% and 85% of patients eligible for follow-up at 30 days and 12 months, respectively. Patients presented with branch vessel obstruction/compromise (73% [53 of 73]), aortic rupture (22% [16 of 73]), or both (5.5% [4 of 73]). Covered stent graft main body was used in all patients (median, 1; range, 1-3; 1 stent graft used in 70% [51 of 73]). Bare dissection stent was used in 58 of 73 patients (80%); main reasons for not using a bare dissection stent include limited dissection and absence of false lumen flow. Five deaths (6.8%) occurred within 30 days (due to presenting aortic dissection, ischemic bowel, multiple organ failure, stroke, and aortic rupture, respectively). Thirty-day MAEs included myocardial infarction (1), bowel ischemia (1), stroke (5), paraplegia/paraparesis (4), chronic renal insufficiency/renal failure requiring dialysis (7), and prolonged ventilator support (10). Between 31 and 365 days, 9 deaths occurred (1 related to dissection repair), and 3 patients experienced MAEs (2 with chronic renal insufficiency/renal failure requiring dialysis, 1 with stroke and bowel ischemia). Within 12 months, 9 patients underwent secondary interventions; no patients required conversion to open surgery. According to a mixed model, the mean true lumen diameter increased from 22.3 mm to 33.8 mm in the descending thoracic aorta and from 18.4 mm to 25.8 mm in the abdominal aorta from preprocedure to 12 months. Concomitantly, the mean false lumen diameter decreased from 18.4 mm to 8.6 mm in the descending thoracic aorta and from 15.3 mm to 12.3 mm in the abdominal aorta. Growth (>5 mm) of the maximum transaortic diameter was seen in 11% (5 of 45, thoracic) and 17% (7 of 41, abdominal) of patients at 12 months. These initial results from the STABLE II study appeared favorable in terms of clinical and anatomical outcomes for the treatment of rupture and malperfusion in the setting of acute cTBAD. Five-year follow-up is ongoing.

The Impact of Aneurysm Morphology and Anatomic Characteristics on Long-Term Survival after Endovascular Abdominal Aortic Aneurysm Repair

Hostile anatomic characteristics in patients undergoing endovascular abdominal aortic aneurysm repair (EVAR) and the placement of endografts not in concordance with the specific device anatomic guidelines (or instructions for use [IFU]) have shown decreased technical success of the procedure. But these factors have never been evaluated in regard to patient postoperative survival. We sought to assess the association between survival and (1) aneurysm anatomy and characteristics and (2) implantation in compliance with manufacturer's anatomic IFU guidelines in patients undergoing endovascular aortic aneurysm repair. The cohort included 273 consecutive patients who underwent EVAR at Baylor Heart and Vascular Hospital between January 1, 2002 and December 31, 2009 and had their preoperative computed tomography (CT) scan digitally retrievable. The CT scans and operative notes were then reviewed, and the anatomic severity grading (ASG) score, maximum aneurysm diameter, thrombus width, patency of aortic side branch vessels, and implantation in compliance with IFU guidelines were assessed. The unadjusted association between survival (assessed until November 1, 2011) and these variables was assessed with the Kaplan-Meier method. Moreover, propensity-adjusted (for a comprehensive array of clinical and nonclinical risk factors) proportional hazard models were developed to assess the adjusted associations. Seven (2.56%) patients died within 30days from EVAR, and 88 (30.04%) patients died during the study follow-up. Patient mean survival was 6.3years. The unadjusted analysis showed a statistically significant association between survival and thrombus width (P=0.007), ASG score (P=0.004), and implantation in compliance with IFU guidelines (P=0.007). However, the adjusted analysis revealed that none of the anatomic and compliance factors were significantly associated with long-term survival (ASG, P=0.149; diameter, P=0.836; thrombus, P=0.639; patency, P=0.219; and implantation compliance, P=0.219). Unfavorable aneurysm morphologic characteristics and endograft implantation not in compliance with IFU guidelines did not adversely affect patient survival after EVAR in this group of patients. This implies that unfavorable anatomy, even that which would necessitate implantation of the EVAR device outside of the IFU guidelines, should not necessarily contraindicate EVAR.

Correlation of computed tomography angiography and digital subtraction angiography in nonspecific aortoarteritis (Takayasu′s arteritis)

Background: Nonspecific aortoarteritis (NSAA) or Takayasu's arteritis is an inflammatory disorder of large elastic arteries. Imaging plays a vital role in the diagnosis and treatment of such patients. Hence, one should be aware of the imaging profile of NSAA, and the advantages and disadvantages of computed tomography angiography (CTA) and digital subtraction angiography (DSA), which are the two most commonly performed imaging investigations in these patients. Aims: The aims of this study were to evaluate the imaging profile of NSAA in a sub-group of the Indian population, and to compare the efficacy of CTA and DSA in the diagnosis of this entity. Materials and Methods: A prospective study was conducted with 25 patients, who underwent CTA and DSA for suspected NSAA in our institute between January 2009 and September 2010. The data was analyzed in terms of the demographic characteristics of the study group, most common artery involved, most common angiographic type of NSAA, and the CTA and DSA findings in the study group. Results: NSAA predominantly affects young females, as seen in this study, wherein 20 of the 25 patients were females (80%). The most common age group affected was 20-25 years. Most of the patients (44%) had involvement of more than two vessels. The most common aortic branch vessel to be involved was the renal artery. DSA was more sensitive than CTA in detecting aortic or branch vessel stenosis. However, CTA scores over DSA in the evaluation of vessel wall thickness. Conclusion: The imaging profile of NSAA in the Indian population is different from the Japanese population in that the most common branch vessel involved in the Indian population is the renal artery, as opposed to the subclavian artery in the Japanese population. CTA and DSA are both very effective in the diagnosis of NSAA. However, the best imaging modality in NSAA is DSA since it can be used for diagnosis as well as the treatment of NSAA.

Endovascular treatment of aortic lesions involving branch vessels with multi-layer bare stents

Aortic lesions involving branch vessels have always been a great challenge for vascular surgeons. Endovascular repair are growing to take place of traditional open repair for less invasion and lower complication rates. Despite rapid developments in endovascular instruments have been achieved in the last decade, and endovascular techniques such as fenestration stents have been applied in the treatment of aortic lesions involving branch vessels. However, endovascular repairing aortic lesions involving branch vessels remains being restricted by rigorous indication selection as well as requirements of advanced experiences and sophisticated skills. Recently, several studies about treating aortic lesion involving branch vessels with multi-layer bare stents have been reported, the primary results were encouraging and brought new visions for the management of such disease. More approving clinical evidences about the safety and efficacy of multi-layer stents are anticipated.

Predictive Factors for the Development of Type 2 Endoleak Following Endovascular Aneurysm Repair.

Type 2 endoleak (T2EL) is the most common complication following endovascular aneurysm repair (EVAR) for abdominal aortic aneurysms. The management of T2ELs is controversial due to the relatively low incidence of negative outcomes when secondary intervention is avoided. Some studies challenge this practice as demonstrated by adverse events following conservative treatment of T2ELs. Evidence has shown that the preoperative computed tomographic angiogram can predict the development of T2EL based on a patient's arterial anatomy, specifically vessels associated with increased rates of post-EVAR endoleak development. Preoperative embolization of those aortic branch vessels associated with T2ELs has shown decreased rates of postoperative complications and may result in a decreased need for surveillance and reintervention.

Percutaneous interventions in aortic disease.

Percutaneous access techniques for diagnostic and therapeutic approaches to the coronary and aortic branch vessels have been the mainstay of cardiovascular interventions for several decades. The development of catheter-based technologies to treat traumatic and degenerative pathology of the thoracic and abdominal aorta initially required the use of direct femoral access via open incisions because of the size of the devices and their delivery sheaths. Although the endovascular repair of infrarenal aortic aneurysms (EVAR)1 ushered in an entirely new concept for managing aortic pathology, there was a concomitant development of a new series of complications associated with open vascular access. Of the devices approved by the US Food and Drug Administration, the profiles of the currently available components ranges from 9F to 25F inner diameter, which correlates to 11F to 27F outer diameter. In particular, delivery systems for thoracic endografts have 22F to 27F outer diameter and are traditionally placed via femoral artery cut-down or surgically created conduits. With the evolution of devices with smaller sheaths, the development of closure devices, and noninvasive imaging studies to assess the suitability of arteries for percutaneous access, there have been major changes in the approach and timing of aortic interventions. Over the years, many closure devices have been marketed to decrease the need for manual compression or reversal of anticoagulation after transfemoral percutaneous diagnostic or therapeutic interventions. To date, only suture-mediated closure devices have been used to manage larger catheter-based percutaneous interventions. Two suture-mediated percutaneous closure devices currently are available for potential off-label use in the closure of endograft access sites: Perclose Prostar XL and Perclose ProGlide (Abbott Vascular, Redwood City, CA). The Perclose Prostar XL device comes in 2 different sizes. The Prostar XL 8 is designed for closure of 6.5F to 8F access sites, and Prostar XL 10 is for closure …

Abdominal Aortic Aneurysm Anatomic Severity Grading Score Predicts Aortic Branch Vessel Complications, Nonaortic Adverse Events, and Survival

Abdominal Aortic Aneurysm Anatomic Severity Grading Score Predicts Aortic Branch Vessel Complications, Nonaortic Adverse Events, and Survival

Role of cardiovascular echo in patients with Takayasu arteritis.

Takayasu arteritis is an important differential diagnosis in young female patients presenting with fever, fatigue, hypertension, and/or neck pain. Aortic arch branch vessels are frequently affected and the carotid artery can have diffuse, homogeneous wall thickening, known as the 'macaroni sign'. The descending aorta can be stenotic with 'pseudo-coarctation'. Cardiovascular echo plays an important role in the screening and characterization of arterial lesions in patients with Takayasu arteritis.

Can early computed tomography angiography after endovascular aortic aneurysm repair predict the need for reintervention in patients with type II endoleak?

This study was designed to identify parameters on CT angiography (CTA) of type II endoleaks following endovascular aortic aneurysm repair (EVAR) for abdominal aortic aneurysm (AAA), which can be used to predict the subsequent need for reinterventions. We retrospectively identified 62 patients with type II endoleak who underwent early CTA in mean 3.7 ± 1.9 days after EVAR. On the basis of follow-up examinations (mean follow-up period 911 days; range, 373-1,987 days), patients were stratified into two groups: those who did (n = 18) and those who did not (n = 44) require reintervention. CTA characteristics, such as AAA, endoleak, as well as nidus dimensions, patency of the inferior mesenteric artery, number of aortic branch vessels, and the pattern of endoleak appearance, were recorded and correlated with the clinical outcome. Univariate and receiver operating characteristic curve regression analyses revealed significant differences between the two groups for the endoleak volume (surveillance group: 1391.6 ± 1427.9 mm(3); reintervention group: 3227.7 ± 2693.8 mm(3); cutoff value of 2,386 mm(3); p = 0.002), the endoleak diameter (13.6 ± 4.3 mm compared with 25.9 ± 9.6 mm; cutoff value of 19 mm; p < 0.0001), the number of aortic branch vessels (2.9 ± 1.2 compared with 4.2 ± 1.4 vessels; p = 0.001), as well as a "complex type" endoleak pattern (13.6 %, n = 6 compared with 44.4 %, n = 8; p = 0.02). Early CTA can predict the future need for reintervention in patients with type II endoleak. Therefore, treatment decision should be based not only on aneurysm enlargement alone but also on other imaging characteristics.

Evaluation of Low-Dose CT Angiography With Model-Based Iterative Reconstruction After Endovascular Aneurysm Repair of a Thoracic or Abdominal Aortic Aneurysm

The objective of our study was to evaluate image quality and overall adequacy of low-dose CT angiography (CTA) with model-based iterative reconstruction (MBIR) in patients who had undergone endovascular aneurysm repair (EVAR) of a thoracic or abdominal aortic aneurysm. Thirty patients, all of whom had undergone standard-dose CTA performed previously with adaptive statistical iterative reconstruction (ASIR), underwent low-dose CTA for surveillance after EVAR. Two radiologists randomly evaluated both studies, and quality parameters were assessed. The maximal aneurysm diameter was measured, and the images were evaluated to see whether an endoleak was present. The image noise and contrast-to-noise ratio (CNR) were measured. The volume CT dose index and dose-length product were recorded. The mean image score for low-dose CTA was acceptable to very good in all categories of assessment. There was no significant difference between low-dose CTA and standard-dose CTA in the evaluation of the stent lumen. Subjective assessments of stent configuration, aneurysm outline, aortic branch vessel outline, overall adequacy of vascular imaging, and overall adequacy of solid organ imaging were superior on standard-dose CTA. Interobserver agreement for endoleak detection was higher for low-dose CTA. There was no significant difference in the mean aneurysm diameter between the two readers on low-dose CTA and standard-dose CTA. The effective radiation dose for low-dose CTA was lower than standard-dose CTA during both the arterial (mean, 4.4 vs 16.2 mSv, respectively) and the delayed (2.4 vs 6.7 mSv) phase acquisitions. The measured image noise was lower (14.7 vs 19.3 HU) and CNR was higher (25.6 vs 17.1) on the low-dose CTA studies than on the standard-dose CTA studies. Low-dose CTA with MBIR enables up to 73% dose reduction as compared with CTA performed with ASIR while maintaining diagnostic adequacy for CTA surveillance of patients who have undergone EVAR of a thoracic or abdominal aortic aneurysm.

Systematic review of chimney and periscope grafts for endovascular aneurysm repair

Conventional endovascular aneurysm repair (EVAR) needs a proximal aortic seal zone that is free from aortic branch vessels. The modified application of conventional EVAR devices using adjuvant chimney or periscope grafts is described as a pragmatic alternative to custom-made fenestrated and branched endografts. This systematic review examined the application and outcomes of chimney or periscope grafts for aortic aneurysm. A search was performed for all studies of chimney or periscope grafts for EVAR. Clinical details and outcome in terms of technical success, survival, freedom from endoleak and branch vessel patency were examined. Twenty-four studies describing 234 patients who underwent EVAR with one or more chimney or periscope grafts for aortic branch vessels were identified. Most procedures were elective; only 62 (26.5 per cent) were performed urgently. There were 176 patients with an abdominal aortic aneurysm and 58 with a thoracic or thoracoabdominal aortic aneurysm. Three hundred and seventy-six branch vessels were perfused. Twelve patients (5.1 per cent) died within 30 days of aneurysm repair. Twenty-seven patients (11.5 per cent) developed a type I endoleak. After a mean(s.d.) follow-up of 12(5) months, seven branch vessels stents had occluded. These highly selected data support the potential value of chimney and periscope graft techniques for patients with challenging aortic aneurysm morphology. There is a lack of medium- and long-term follow-up data.

Editorial Comment: Aortic branch vessel compromise vs clinically overt malperfusion in acute type A aortic dissection

branches. The complexity is a clear limitation of the proposed classification system. The authors state in their article that ‘malperfusion syndromes associated with acute aortic dissection represent only a small proportion of identified aortic branch compromises’. However, this statement questions the clinical implications of the presented classification system. Despite a significant number of high-risk perfusion patterns in a total of 61 aortic branches before the surgery, clinically overt malperfusion syndromes were present in only 16 (26%) patients (9 patients with cerebral malperfusion and 7 with lower limb ischaemia) preoperatively. A total of 92% of these high-risk perfusion patterns were resolved sufficiently by means of the central aortic repair, without any clinical evidence of postoperative end-organ ischaemia. High-risk perfusion patterns persisted in only five (8%) aortic branches (i.e. four cervical branches and one abdominal branch) postoperatively. However, only a single patient suffered a new-onset cerebral malperfusion event postoperatively. Therefore, the clinical relevance of asymptomatic high-risk perfusion patterns in the aortic branches, as defined by means of CT imaging, may not be definitely answered by the present study. Moreover, the persistence of asymptomatic high-risk perfusion patterns after the surgery precludes any clinical implications in this specific cohort of aortic dissection patients. Given the large proportion of aortic dissection patients with highrisk perfusion patterns and no deleterious end-organ malperfusion, the role of percutaneous endovascular interventions remain unclear. However, as fairly recognized by the authors, the study cohort is very small, with only a few cases of clinically overt end-organ malperfusion. Despite the above-mentioned limitations, this study provides a very detailed picture of the involvement of the aortic branches in the acute type A aortic dissection before and after surgery, which is followed by meaningful and sharable comments and conclusions. The authors were able to convincingly demonstrate the key role of central aortic repair in resolving the high-risk perfusion patterns in the aortic branches as well as the clinically overt malperfusion. Another important message derived from this article is that the II-b-2 perfusion patterns are not always static lesions and may be resolved by the central aortic repair, particularly in the cervical aortic branches. Incomplete decompression of the false lumen after central aortic repair may be encountered