Endovascular Stent-Graft Treatment of Thoracic Aortic Disease

A Deformable Constraint Transport Network for Optimal Aortic Segmentation From CT Images

Aortic segmentation from computed tomography (CT) is crucial for facilitating aortic intervention, as it enables clinicians to visualize aortic anatomy for diagnosis and measurement. However, aortic segmentation faces the challenge of variable geometry in space, as the geometric diversity of different diseases and the geometric transformations that occur between raw and measured images. Existing constraint-based methods can potentially solve the challenge, but they are hindered by two key issues: inaccurate definition of properties and inappropriate topology of transformation in space. In this paper, we propose a deformable constraint transport network (DCTN). The DCTN adaptively extracts aortic features to define intra-image constrained properties and guides topological implementation in space to constrain inter-image geometric transformation between raw and curved planar reformation (CPR) images. The DCTN contains a deformable attention extractor, a geometry-aware decoder and an optimal transport guider. The extractor generates variable patches that preserve semantic integrity and long-range dependency in long-sequence images. The decoder enhances the perception of geometric texture and semantic features, particularly for low-intensity aortic coarctation and false lumen, which removes background interference. The guider explores the geometric discrepancies between raw and CPR images, constructs probability distributions of discrepancies, and matches them with inter-image transformation to guide geometric topology in space. Experimental studies on 267 aortic subjects and four public datasets show the superiority of our DCTN over 23 methods. The results demonstrate DCTN's advantages in aortic segmentation for different types of aortic disease, for different aortic segments, and in the measurement of clinical indexes.

In Vivo Efficacy of an Adhesive Bioresorbable Patch to Treat Aortic Dissections

Endovascular repair of aortic dissection still presents significant limitations. Preserving the mechanical and biological properties set by the aortic microstructure is critical to the success of implantable grafts. In this paper, we present the performance of an adhesive bioresorbable patch designed to cover the entry tear of aortic dissections. We demonstrate the power of using a biomimetic scaffold in a vascular environment.

Post-operative computed tomography imaging evaluation of ascending aorta surgery

Ascending thoracic aorta disease is often a life-threatening condition. Aortic aneurysm and aortic dissection are the most frequent ascending aorta diseases requiring surgical intervention. Surgical repair techniques of the ascending aorta are various; they include reconstruction of the ascending aorta by using a graft with or without a prosthetic valve, reconstruction with a composite artificial graft or using a biological graft, and reconstruction of the ascending aorta with a composite graft preserving the native valve and arch repair. The radiologist plays a key role in the identification of post-operative complications; differentiation from normal postoperative findings is fundamental. Our aim is to discuss the main diseases affecting the ascending aorta requiring surgery and the different techniques used to treat them. We also discuss the normal computed tomography (CT) imaging findings and after-surgery complications.

CT of suspected thoracic acute aortic injury in the emergency department: is routine abdominopelvic imaging worth the additional collective radiation dose?

This study aimed to determine the incidence of non-traumatic acute aortic injury (AAI) extending from the chest into the abdomen or pelvis in emergency department (ED) patients with acute aortic syndrome (AAS), to estimate the effective dose of the abdominopelvic portion of these CT exams, and to compare the number needed to screen (NNS) with the collective population radiation dose of imaging those stations. All patients (n = 238) presenting to the ED with AAS between March 2014 and June 2015 who were imaged per CT AAI protocol (noncontrast and contrast-enhanced CT angiography of the chest, abdomen, and pelvis) were retrospectively identified in this IRB-approved HIPAA-compliant study. The Stanford classification for positive cases of AAI was further subclassified based on chest, abdominal, or pelvic involvement. The dose length product (DLP) of each exam was used to estimate the dose of the abdominal and pelvic stations and the collective effective dose for the population. There were five cases of aortic dissection (AD) and two of intramural hematoma (IMH), with an AAI incidence of 2.9/100. Three cases of AAI were confined to the chest. Two cases of AAI were confined to the chest and abdomen, and two cases involved the chest, abdomen, and pelvis. There was only one case of AAI involving the ascending aorta that extended into the abdomen or pelvis. The number needed to screen to identify (a) AAI extending from the chest into the abdomen or pelvis was 59.5 and (b) Stanford A AAI extending into the abdomen or pelvis was 238. The estimated mean effective dose for the abdominopelvic stations were unenhanced abdomen 2.3 mSv, unenhanced pelvis 3.3 mSv, abdominal CTA 2.5 mSv, and pelvic CTA 3.6 mSv. The collective effective doses to the abdomen and pelvis with unenhanced CT and CTA in 59.5 patients and 238 patients were 761.6 and 3046.4 mSv, respectively. While the estimated mean effective dose for imaging of the abdominopelvic stations are low, the collective effective dose should also be considered. It may be beneficial to modify or omit routine unenhanced CT and/or CTA of the abdomen/pelvis in this patient population in the absence of abdominal symptoms, and image the abdomen and pelvis in positive thoracic cases only.

Midterm results of type B intramural hematoma endovascular treatment

BACKGROUND

Recently, intramural hematoma (IMH) has been characterized as a rare variant of aortic dissection, falling within the acute aortic syndromes (AAS). Although aortic endovascular treatment seems to provide good results, no consensus has been established regarding the optimal management of IMH affecting the descending thoracic aorta (IMH B). The aim of this study was to assess long-term clinical and morphological results of IMH B treated with a stent graft.

METHODS

Between 2002 and 2013, 15 of the 423 (3.5%) consecutive patients with AAS were found to have IMH B. During follow-up, complications related to IMH B were observed in 10 patients, including 5 during the acute period (<14 days). Surgical indications were ulcerations, refractory pain, aneurysm evolution, aortic rupture, and pleural effusion. An endovascular approach was taken for all forms with suitable anatomy.

RESULTS

Technical success rate was 100%, with complete exclusion of lesions of the descending thoracic aorta in all cases treated with a stent graft. No neurological complications or deaths occurred within the first 30 postoperative days, nor at the end of the mean follow-up of 46 months (1-137 months). After the aortic stent graft, partial or complete regression of the hematoma was observed in all cases.

CONCLUSIONS

IMH B is most often a progressive disease requiring long-term monitoring. In case of complications, stent-graft treatment of the descending thoracic aorta can be performed successfully in most cases. This procedure appears to be a safe technique that provides very good long-term results, with favorable remodeling of the aorta.

Endovascular repair of aortic dissection and intramural hematoma: indications and serial changes

Thoracic aortic dissection (AD) is one of the most common aortic emergencies. It can be fatal if not promptly diagnosed and treated. Intramural hematoma (IMH) of the aorta is recognized as distinct from classic (double-barreled) AD. IMH also frequently leads to aortic emergency, which can be fatal unless rapidly diagnosed and treated. Recently, thoracic endovascular aortic repair (TEVAR) has been used for the treatment of complications caused by AD. TEVAR is also a viable option for the treatment of complicated IHM. In this article, we review the details of TEVAR as treatment options for AD and IMH, including the indications for TEVAR, imaging, and follow-up.

The role of multidetector-row CT in the diagnosis, classification and management of acute aortic syndrome

The term "acute aortic syndrome" (AAS) encompasses several non-traumatic life-threatening pathologies of the thoracic aorta presenting in patients with a similar clinical profile. These include aortic dissection, intramural haematoma and penetrating atherosclerotic ulcers. These different pathological entities can be indistinguishable on clinical grounds alone and may be confused with other causes of chest pain, including myocardial infarction. Multidetector-row CT (MDCT) is the current modality of choice for imaging AAS with a sensitivity and specificity approaching 100%. Early diagnosis and accurate radiological classification is associated with improved clinical outcomes in AAS. We review the characteristic radiological features of the different pathologies that encompass AAS and highlight the vital role of MDCT in determining the management of these life-threatening conditions.

Endovascular repair of thoracic and abdominal aortic ruptures: a single-center experience

PURPOSE

We aimed to present our preliminary single-center experience of the endovascular management of thoracic and abdominal aortic ruptures.

MATERIALS AND METHODS

Between September 2010 and May 2012, 11 consecutive patients (nine males, two females; age range, 26-80 years) with thoracic and abdominal aortic ruptures underwent endovascular repair in our unit. Thoracoabdominal computed tomography (CT) angiography was performed for diagnosis and follow-up. Patients were selected for endovascular repair by a cardiovascular surgeon, anesthesiologist, and interventional radiologist. All repairs were performed using commercially available stent-grafts. The patients were followed up with CT angiography before discharge, at six months, and yearly thereafter.

RESULTS

Three patients died by day 30. One patient died due to an unsuccessful procedure and hemodynamic instability; two patients died because of comorbidities. The other eight patients were followed for six to 24 months after the procedure. No endoleaks or late ruptures were observed during the follow-up period. The patient with iatrogenic thoracic aortic rupture developed paraplegia after the procedure.

CONCLUSION

Reduced mortality due to aortic rupture has been reported with the expanding use of endovascular repair. Reports of small centers are important because of the rarity of these pathologies, and because transferring patients with aortic rupture to a referral center is not usually possible.

Percutaneous transluminal intervention and antiplatelet therapy following endovascular graft exclusion for Stanford B thoracic aortic dissection

OBJECTIVE

To evaluate the safety and feasibility of percutaneous coronary intervention and antiplatelet therapy in patients who have undergone endovascular graft exclusion.

METHODS

From January 2005 to July 2007, percutaneous transluminal intervention (PCI) was performed in 13 patients who had undergone endovascular graft exclusion for the treatment of either acute or chronic Stanford B aortic dissection. Anticoagulant and antiplatelet treatments were administered according to the standard protocol. Patients were followed up for a mean period of 11 months. Clinical characteristics, false lumen thrombosis and angiographic data were collected.

RESULTS

PCI was technically successful in all 13 patients and no severe complications, including death, paraplegia or renal failure occurred during hospitalization. Complete false lumen thrombosis was observed in all patients within 6 months. There were no major complications such as death, dissection rupture, or aneurysm development during the follow-up period.

CONCLUSION

Our data suggested that PCI and standard antiplatelet therapy are feasible and safe in patients who have undergone endovascular stent graft exclusion for Stanford B aortic dissection.

Acute aortic syndrome: CT findings

Acute aortic syndrome (AAS) is a constellation of potentially life-threatening acute aortic diseases. The spectrum includes penetrating atherosclerotic ulcer, intramural haematoma, dissection, and unstable thoracic aneurysm. AAS cannot be reliably diagnosed clinically and multidetector computed tomography (MDCT) has revolutionized the diagnosis and management of this group of conditions in the acute setting due to its availability, speed, and accuracy. The purpose of this review is to illustrate key MDCT findings of AAS. Imaging techniques, radiological findings, and common pitfalls are also discussed.

Unusual complications of endovascular repair of the thoracic aorta: MDCT findings

With the development of minimally invasive surgical techniques, endovascular stent-graft placement has become an accepted and widely used alternative to the traditional surgical repair of aortic disease and is gaining acceptance as the treatment of choice. Many studies show that endovascular stent-graft therapy is safe and effective, although complications related to this treatment are also recognised. Although the incidence of major complication is low, neurological sequelae remain the major concern of endovascular repair. With growing experience, however, the spectrum of mid- and long-term complications has broadened to include potentially disastrous events, other than paraplegia or stroke, that require diligent surveillance. Three-dimensional data sets acquired quickly by multidetector computed tomography (MDCT) allow multiplanar reformations and 3D viewing, as well as quantitative assessment of vessel lumens, walls and surroundings. Although a large portion of radiologists will not be involved in the actual endograft deployment, many will be involved in the interpretation of postprocedural surveillance studies. Accordingly, the goal of this report is to summarise our experience with the presentation, diagnostic approach, management and outcomes of these unusual, but potentially catastrophic, postendovascular aortic repair complications to highlight their significance and increase familiarity with them among the imaging community. Increasing awareness of these complications may facilitate rapid diagnosis and/or triage and treatment.

Failed surgical ligation of the proximal left subclavian artery during hybrid thoracic endovascular aortic repair successfully managed by percutaneous plug or coil occlusion: a report of 3 cases

Open surgical rerouting and proximal ligation of one or more supra-aortic vessels prior to endovascular stent-graft placement has become an alternative to major open thoracic surgery in the treatment of complex thoracic aortic disease. Complications owing to failed surgical ligation of the left subclavian artery are rare. In this report, 3 cases of failed ligation are presented. Diagnosis was made by CT-scan and treatment was performed by transcatheter coil and plug embolization, avoiding redo neck surgery.

Incomplete endograft apposition to the aortic arch: bird-beak configuration increases risk of endoleak formation after thoracic endovascular aortic repair

PURPOSE

To determine the clinical importance of the bird-beak configuration after thoracic endovascular aortic repair (TEVAR).

MATERIALS AND METHODS

The institutional review board approved this retrospective study and waived the requirement to obtain informed consent from patients. Sixty-four patients (40 men, 24 women; mean age, 64 years) who underwent TEVAR were evaluated. The treated diseases included dissection (n = 29), degenerative aneurysm (n = 13), acute traumatic transection (n = 8), pseudoaneurysm (n = 4), penetrating aortic ulcer (n = 6), intramural hematoma (n = 2), and mycotic aneurysm (n = 2). Bird-beak configuration, defined as the incomplete apposition of the proximal endograft with a wedge-shaped gap between the device and the aortic wall, was assessed with postprocedural CT angiography. The presence and length of the bird-beak configuration were compared with the formation of endoleaks and adverse clinical events.

RESULTS

Endoleaks were detected in 26 (40%) of the 64 patients, including 14 with type Ia endoleak formation, one with type Ib endoleak formation, six with type II endoleak formation (from the left subclavian artery), two with type IIo endoleak formation (from other arteries), and three with type III endoleak formation. Bird-beak configuration was observed in 28 (44%) of 64 patients and correlated significantly with the risk of developing a type Ia or IIa endoleak (P < .01). Mean bird-beak length was significantly longer (P < .01) in patients with a type Ia or II endoleak (mean length, 14.3 and 13.9 mm, respectively) than in patients without endoleaks (mean length, 8.4 mm). Adverse events included early aortic-related death in three patients, additional treatment for endoleak in eight patients, and stent-graft collapse or infolding in six patients.

CONCLUSION

Detection of bird-beak configuration is helpful in the prediction of adverse clinical events after TEVAR.

CT and MRI in diseases of the aorta

OBJECTIVE

This review focuses on the role of CT and MRI in the diagnosis, follow-up, and surgical planning of aortic aneurysms and acute aortic syndromes, including aortic dissection, intramural hematoma, and penetrating aortic ulcer. It also provides a systematic approach to the definition, causes, natural history, and imaging principles of these diseases.

CONCLUSION

An understanding of the pathophysiology, natural history, and imaging features is the key to successful diagnosis and appropriate management of patients with these aortic diseases.

Multidetector CT of thoracic aortic aneurysms

Thoracic aortic aneurysms (TAAs) can be broadly divided into true aneurysms and false aneurysms (pseudoaneurysms). True aneurysms contain all three layers of the aortic wall (intima, media, and adventitia), whereas false aneurysms have fewer than three layers and are contained by the adventitia or periadventitial tissues. Multidetector computed tomographic (CT) angiography allows the comprehensive evaluation of TAAs in terms of morphologic features and extent, presence of thrombus, relationship to adjacent structures and branches, and signs of impending or acute rupture, and is routinely used in this setting. Knowledge of the causes, significance, imaging appearances, and potential complications of both common and uncommon aortic aneurysms, as well as of the normal postoperative appearance of the thoracic aorta, is essential for prompt and accurate diagnosis. Supplemental material available at http://radiographics.rsnajnls.org/cgi/content/full/29/2/537/DC1.

Endovascular stent-graft management of aortic intramural hematomas

PURPOSE

To report initial experience with endovascular stent-grafting in aortic intramural hematoma (IMH).

MATERIALS AND METHODS

From 2000 to 2006, 15 patients (mean age, 67 years; range, 54-83 y) underwent endovascular treatment of aortic IMH. Thirteen patients were admitted for acute aortic syndrome and two for traumatic aortic injury. An endovascular procedure was performed as primary treatment for four patients (type A IMH, n = 3; type B IMH, n = 1) and as a second-line therapy in 11 patients because of unfavorable evolution (type A IMH, n = 1; type B IMH, n = 10). All stent-grafts were placed in the descending aorta, even for type A IMH. The mean follow-up was 21 months (range, 6-72 months).

RESULTS

The primary success rate was 93%, with complete exclusion of the lesion (n = 14). Exclusion was partial for one patient with a type I endoleak (7%). The 30-day mortality rate was zero. IMH evolution was favorable in all cases, with decreased aortic wall thickening (n = 8) or complete regression (n = 7). Complications associated with endovascular repair were mainly related to aneurysm formation (20%). The late death rate was 7%.

CONCLUSIONS

Endovascular stent-graft treatment can be performed in the management of complicated IMH, even in some cases of type A IMH, when an intimal lesion is located in the isthmus or descending aorta with contraindications to surgery. This procedure offers low morbidity and mortality rates, representing a feasible therapeutic option especially for elderly patients with comorbidities. Further studies are necessary to confirm these preliminary results.

Acute traumatic aortic injury: imaging evaluation and management

Despite recent advances in prehospital care, multidetector computed tomographic (CT) technology, and rapid definitive therapy, trauma to the aorta continues to be a substantial source of morbidity and mortality in patients with blunt trauma. The imaging evaluation of acute aortic injuries has undergone radical change over the past decade, mostly due to the advent of multidetector CT. Regardless of recent technologic advances, imaging of the aorta in the trauma setting remains a multimodality imaging practice, and thus broad knowledge by the radiologist is essential. Likewise, the therapy for acute aortic injuries has changed substantially. Though open surgical repair continues to be the mainstay of therapy, percutaneous endovascular repair is becoming commonplace in many trauma centers. Here, the historical and current status of imaging and therapy of acute traumatic aortic injuries will be reviewed.

Risk factors for perioperative stroke during thoracic endovascular aortic repairs (TEVAR)

PURPOSE

To determine the clinical and anatomical risk factors for cerebrovascular accidents (CVA) in patients undergoing thoracic endovascular aortic repair (TEVAR).

METHODS

Between September 2000 and December 2006, 196 patients (135 men; mean age 68.6+/-13.5 years, range 17-92) underwent TEVAR for a variety of aortic pathologies. The majority (156, 79.6%) were treated with the TAG stent-graft. Demographics, pathologies, intraoperative procedure-related measures, device usage, and postoperative outcomes were assessed. CVA was defined as a new focal or global neurological (motor or sensory) deficit lasting >48 hours associated with acute intracranial abnormalities on computed tomography or magnetic resonance brain imaging. Spinal cord ischemia was excluded. In a subset of patients with planned left subclavian artery (LSA) coverage and an incomplete circle of Willis or a dominant left vertebral artery, prophylactic carotid-subclavian bypasses were performed.

RESULTS

Nine (4.6%) patients suffered a CVA. Factors not predictive of a CVA on univariate analysis included aortic pathology, urgency of repair, ASA classification, type of anesthesia, blood loss, procedure time, and device used. Proximal extent of repair (with or without extra-anatomical revascularization) was significantly associated with a higher incidence of strokes (zones 0-2 versus 3-4, p=0.025). Five (55.6%) patients with a CVA had documented intraoperative hypotension (systolic blood pressure<80 mmHg). Additionally, while 2 patients had hemispheric infarcts, 5 had acute posterior circulation infarcts involving the cerebellum and brainstem; a single patient had both anterior and posterior circulation infarcts. Seven of the CVA patients had proximal coverage of the thoracic aorta in zones 0-2; of these, 6 had posterior circulation infarcts. Selective LSA revascularization based on preoperative cerebrovascular imaging resulted in lower rates of CVA (6.4% to 2.3%, p=0.30) and posterior circulation infarcts (5.5% to 1.2%, p=0.13).

CONCLUSION

Proximal extent of repair may serve as a surrogate marker for greater severity of degenerative disease of the aortic arch. Avoidance of intraoperative hypotension and preservation of antegrade vertebral perfusion may be important in prevention of posterior circulation strokes.

Endovascular stent-graft treatment of thoracic aortic syndromes: a 7-year experience

Thoracic aortic diseases (TAD) are relatively frequent conditions associated with high mortality. Recently, several reports have demonstrated the safety and efficacy of endovascular stent-graft (EVG) placement for TAD as an alternative to open surgery. We report our experience in management of thoracic aortic syndrome on 56 consecutive patients with TAD that underwent endovascular stent-graft repair. MDCT angiography was used in all patients to provide preprocedure evaluation and measurements. In particular it is necessary to evaluate the proximal and distal landing zones of the stent-graft. All EVGs in our series were placed successfully. Conversion to open surgery was never required. Six patients (10.7%) died early after the stent-graft deployment. During follow-up four more patients died. The endoleak rate was 16.7% (no. 10 pt). We did not observe any case of paraplegia. The present study shows the efficacy of EVG in the long-term follow-up, with an overall survival of 82.1%, which is comparable to that reported in recent studies. In conclusion this technique is emerging as an alternative approach in the treatment of TAD because this approach offers a less invasive therapeutic option to standard surgical techniques, even in patients who have associated diseases that make them poor surgical candidates.

Imaging of implants on chest radiographs: a radiological perspective

Endovascular and percutaneous techniques have emerged as alternatives to surgical management in the treatment for a wide range of congenital and acquired cardiac, non-vascular and vascular conditions. Consequently, there has been an increasing use of implants such as closure devices, vascular stents (coronary, aortic, pulmonary and superior vena cava) and non-vascular stents like oesophageal and tracheo-bronchial stents. A large number of percutaneously sited implants are used for treating congenital cardiac anomalies such as atrial septal defects (ASD), ventricular septal defects (VSD), and patent ductus arteriosus (PDA). These implants take many shapes and forms. The aim of this review is to demonstrate the radiographic appearances of the various types of cardiovascular, bronchial and oesophageal implants that are visible on plain films. A brief outline of the aims and indications of various implant procedures, the general appearance of the commonest types of implants, and the radiological procedures are discussed. All radiologists are likely to come across implanted devices in plain film reporting. Imaging can be useful in identifying the device, assessing the position, integrity, and for the identification of complications related directly to the implant.