Computed Tomography Angiography After Transcatheter and Surgical Aortic Interventions

This comprehensive article reviews the complex realm of aortic surgical and endovascular interventions, focusing on the aortic root, ascending aorta, aortic arch, descending aorta, and abdominal aorta. It outlines the nuances of various procedures, emphasizing the importance of computed tomography angiography acquisition for an accurate assessment. Detailed discussions encompass expected postsurgical/endovascular findings and complications, covering various scenarios, from hematoma and infection to pseudoaneurysms and graft-related issues. This article serves as a crucial resource for radiologists, offering invaluable insights into the complexities of aortic interventions and their subsequent imaging, fostering a comprehensive understanding of diagnostic and management strategies.

Postoperative imaging of thoracic aortic repairs

Imaging plays a crucial role in the postoperative monitoring of thoracic aortic repairs. With the development of multiple surgical techniques to repair the ascending aorta and aortic arch, it can be a daunting challenge for the radiologist to diagnose potential pathologies in this sea of various techniques, each with their own normal postoperative appearance and potential complications. In this paper, we will provide a comprehensive review of the postoperative imaging in the setting of thoracic aortic repairs, including the role of imaging, components of thoracic aortic repairs, the normal postoperative appearance, and potential complications.

CT of Postoperative Repair of the Ascending Aorta and Aortic Arch

While many of the classic open surgical repairs are still used to repair the ascending aorta, management of the aortic arch has become more complex via implementation of newer open surgical and endovascular techniques. Furthermore, techniques are often combined in novel repairs or to allow extended anatomic coverage. As such, a framework that rests on understanding the expected postoperative appearance is necessary for the diagnostic radiologist to best interpret CT studies in these patients. After reviewing the imaging appearances of the common components used in proximal aortic repair, the authors present a structured approach that focuses on the key relevant questions that diagnostic radiologists should consider when interpreting CT studies in these patients. For repair of the ascending aorta, this includes determining whether the aortic valve has been repaired, whether the sinuses of Valsalva have been repaired, and how the coronary arteries were managed, when necessary. In repairs that involve the aortic arch, the relevant considerations relate to management of the arch vessels and the distal extent of the repair. In focusing on these questions, the diagnostic radiologist will be able to identify and describe the vast majority of repairs. Understanding these questions will also facilitate improved understanding of novel repairs, which often use these basic building blocks. Finally, complications-which typically involve infection, noninfectious repair breakdown, hemorrhage, problems with endografts, or disease of the remaining adjacent aorta-will be identifiable as deviations from the expected postoperative appearance. Online supplemental material is available for this article. ^©RSNA, 2021.

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.

Imaging evaluation using computed tomography after ascending aortic graft repair

Prosthetic aortic graft repair is employed in the management of various conditions such as annuloaortic ectasia, ascending aortic aneurysm, type A aortic dissection, and aortic root abscess. Correct interpretation of post-surgical prosthetic graft complications requires familiarity with the expected normal cross-sectional imaging appearance as well knowledge of additional surgical materials used in the repair, which could influence the imaging appearance. Multiple life-threatening complications of a prosthetic ascending aortic graft can be seen in the aorta and vicinity of the operative field. Complications can arise from involvement of the prosthetic aortic graft per se or secondary involvement of the coronary arteries, mediastinum, and sternotomy site. The optimal imaging protocol using multidetector computed tomography allows accurate interpretation of the expected benign postoperative changes as well as complications associated with the prosthetic graft, and differentiation of true complications from their mimickers. This review focuses on the normal imaging appearance of a prosthetic aortic graft on multidetector computed tomography, and imaging evaluation of multiple post-surgical complications that could arise after repair of the ascending aorta and the aortic valve.

Successful medical management of a 16-month chronic type A aortic dissection

Stanford type A dissections usually require surgery because they are associated with high morbidity and mortality. However, there are situations where medical management becomes the definitive treatment. We report the successful medical management of a 16-month chronic type A aortic dissection in a 56-year-old male patient with a past surgical history of ascending aortic aneurysm repair. The dissection is unique because it is distal to the graft and does not extend into the main aortic branches. A review of a patient's surgical history and nonenhanced imaging studies is essential when a type A dissection is discovered. Ascending aortic grafts may preclude the most serious complications of type A dissections.

Imaging of the aortic root on high-pitch non-gated and ECG-gated CT: awareness is the key!

The aortic pathologies are well recognized on imaging. However, conventionally cardiac and proximal aortic abnormalities were only seen on dedicated cardiac or aortic studies due to need for ECG gating. Advances in CT technology have allowed motionless imaging of the chest and abdomen, leading to an increased visualization of cardiac and aortic root diseases on non-ECG-gated imaging. The advances are mostly driven by high pitch due to faster gantry rotation and table speed. The high-pitch scans are being increasingly used for variety of clinical indications because the images are free of motion artifact (both breathing and pulsation) as well as decreased radiation dose. Recognition of aortic root pathologies may be challenging due to lack of familiarity of radiologists with disease spectrum and their imaging appearance. It is important to recognize some of these conditions as early diagnosis and intervention is key to improving prognosis. We present a comprehensive review of proximal aortic anatomy, pathologies commonly seen at the aortic root, and their imaging appearances to familiarize radiologists with the diseases of this location.

Mimics of Complications in the Postsurgical Aorta at CT

Various surgical techniques of the aorta result in expected imaging appearances on CT images that resemble complications such as pseudoaneurysm, perigraft abscess, and dissection. Awareness of these techniques, understanding the clinical situation in which they are performed, and familiarity with the typical appearances and locations of these mimics are essential for accurate interpretation. CT imaging techniques such as electrocardiographic gating and inclusion of a precontrast series can help distinguish an expected postsurgical finding from a complication. Information in the medical record, particularly the operative note, can clarify challenging cases with unusual imaging features. This review article provides examples of expected postsurgical findings at CT mimicking complications. © RSNA, 2019.

Long-Term Postoperative Complication of the Cabrol Procedure Presenting as Recurrent Anterior ST-Segment Elevation Myocardial Infarction

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Development of fistulae between the aneurysm sac and aortic graft can be a potential source of thrombi in patients treated with surgical aortic root replacement.

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Transesophageal echocardiography is an effective tool to assess post-operative complications of the Cabrol procedure.

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Post-operative complications of the Cabrol procedure can have a very delayed initial presentation.

Postcardiovascular Surgery Findings of the Thoracic Aorta

Various disease processes may affect the ascending thoracic aorta, aortic arch, and/or descending thoracic aorta, including aneurysms, dissections, intramural hematomas, penetrating atherosclerotic ulcers, and aortic transection/rupture. Many of those conditions require surgical intervention for repair. Multiple open and endovascular techniques are used for treatment of thoracic aortic pathology. It is imperative that the cardiothoracic radiologist have a thorough knowledge of the surgical techniques available, the expected postoperative imaging findings, and the complications that may occur to accurately diagnose life-threatening pathology when present, and avoid common pitfalls of misinterpreting normal postoperative findings as pathologic conditions.

Postoperative imaging of the aorta

Considerable progress has been made in the management of diseases of the thoracic and abdominal aorta over the past decades, ranging from advances in open repair to the advent of minimally invasive endovascular techniques. Along with this comes an equivalent rise in imaging necessity for these patients, both in preoperative planning and postoperative surveillance. With the growing complexity and diversity of vascular procedures and techniques, it is essential to have a solid understanding of the imaging features and postoperative complications of these procedures to avoid imaging pitfalls. This review is an attempt to define the normal postoperative appearance and important complications of various open and endovascular surgical techniques of the thoracic and abdominal aorta.

Vascular CT and MRI: a practical guide to imaging protocols

Non-invasive cross-sectional imaging techniques play a crucial role in the assessment of the varied manifestations of vascular disease. Vascular imaging encompasses a wide variety of pathology. Designing vascular imaging protocols can be challenging owing to the non-uniform velocity of blood in the aorta, differences in cardiac output between patients, and the effect of different disease states on blood flow. In this review, we provide the rationale behind—and a practical guide to—designing and implementing straightforward vascular computed tomography (CT) and magnetic resonance imaging (MRI) protocols.

Teaching Points

• There is a wide range of vascular pathologies requiring bespoke imaging protocols.

• Variations in cardiac output and non-uniform blood velocity complicate vascular imaging.

• Contrast media dose, injection rate and duration affect arterial enhancement in CTA.

• Iterative CT reconstruction can improve image quality and reduce radiation dose.

• MRA is of particular value when imaging small arteries and venous studies.

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.

Do early postoperative CT findings following type A aortic dissection repair predict early clinical outcome?

PURPOSE

The purposes of this study are to determine the prevalence of specific postoperative CT findings following Stanford type A aortic dissection repair in the early postoperative period and to determine if these postoperative findings are predictive of adverse clinical outcome.

METHODS

Patients who underwent type A dissection repair between January 2012 and December 2014 were identified from our institutional cardiac surgery database. Postoperative CT exams within 1 month of surgery were retrospectively reviewed to determine sizes and attenuation of mediastinal, pericardial, and pleural fluid, and the presence or absence of pneumomediastinum, pneumothorax, or lung consolidation. Poor early clinical outcome was defined as length of stay (LOS) > 14 days. Student's t test and chi-square test were used to determine the relationship between postoperative CT features and early clinical outcome.

RESULTS

Thirty-nine patients (24 M, 15 F, mean age 58.5 ± 13.7 years) underwent type A dissection repair and mean LOS was 17.3 ± 21.2 days. A subset of 19 patients underwent postoperative CTs within 30 days of surgery, and there was no significant relationship between LOS and sizes and attenuation of mediastinal, pericardial, and pleural fluid, and the presence or absence of pneumomediastinum, pneumothorax, or lung consolidation.

CONCLUSIONS

CT features such as mediastinal, pericardial, and pleural fluid were ubiquitous in the early postoperative period. There was no consistent CT feature or threshold that could reliably differentiate between "normal postoperative findings" and early postoperative complications.

Pre- and Postoperative Imaging of the Aortic Root

Three-dimensional datasets acquired using computed tomography and magnetic resonance imaging are ideally suited for characterization of the aortic root. These modalities offer different advantages and limitations, which must be weighed according to the clinical context. This article provides an overview of current aortic root imaging, highlighting normal anatomy, pathologic conditions, imaging techniques, measurement thresholds, relevant surgical procedures, postoperative complications and potential imaging pitfalls. Patients with a range of clinical conditions are predisposed to aortic root disease, including Marfan syndrome, bicuspid aortic valve, vascular Ehlers-Danlos syndrome, and Loeys-Dietz syndrome. Various surgical techniques may be used to repair the aortic root, including placement of a composite valve graft, such as the Bentall and Cabrol procedures; placement of an aortic root graft with preservation of the native valve, such as the Yacoub and David techniques; and implantation of a biologic graft, such as a homograft, autograft, or xenograft. Potential imaging pitfalls in the postoperative period include mimickers of pathologic processes such as felt pledgets, graft folds, and nonabsorbable hemostatic agents. Postoperative complications that may be encountered include pseudoaneurysms, infection, and dehiscence. Radiologists should be familiar with normal aortic root anatomy, surgical procedures, and postoperative complications, to accurately interpret pre- and postoperative imaging performed for evaluation of the aortic root. Online supplemental material is available for this article.

[Acute aortic diseases. Diagnostic imaging and therapy]

Diagnostic imaging is crucial in the work-up of acute aortic diseases. Current imaging algorithms enable radiologists differentiating the various entities with subsequent clinically relevant treatment options. Within this educational overview we focus on non-traumatic acute aortic disease. Recent developments of cross sectional imaging are summarized. As for acute aortic disease, we discuss dissections, intramural hematoma, penetrating aortic ulcer, and aortitis. Current treatment options are presented.

MDCT distinguishing features of focal aortic projections (FAP) in acute clinical settings

Focal aortic projections (FAP) are protrusion images of the contrast medium (focal contour irregularity, breaks in the intimal contour, outward lumen bulging or localized blood-filled outpouching) projecting beyond the aortic lumen in the aortic wall and are commonly seen on multidetector computed tomography (MDCT) scans of the chest and abdomen. FAP include several common and uncommon etiologies, which can be demonstrated both in the native aorta, mainly in acute aortic syndromes, and in the post-surgical aorta or after endovascular therapy. They are also found in some types of post-traumatic injuries and in impending rupture of the aneurysms. The expanding, routine use of millimetric or submillimetric collimation of current state-of-the-art MDCT scanners (16 rows and higher) all the time allows the identification and characterization of these small ulcer-like lesions or irregularities in the entire aorta, as either an incidental or expected finding, and provides detailed three-dimensional pictures of these pathologic findings. In this pictorial review, we illustrate the possible significance of FAP and the discriminating MDCT features that help to distinguish among different types of aortic protrusions and their possible evolution. Awareness of some related and distinctive radiologic features in FAP may improve our understanding of aortic diseases, provide further insight into the pathophysiology and natural history, and guide the appropriate management of these lesions.

Multidetector CT findings of complications of surgical and endovascular treatment of aortic aneurysms

Aortic aneurysms remain a significant problem in the population, and there is a concerted effort to identify, define, image, and treat these conditions to ultimately improve outcomes. The rapid development of diagnostic modalities, operative strategies, and endovascular techniques within the realm of this aortic disease has transformed the field and broadened the spectrum of patients that can be treated with minimally invasive techniques. This investigation has a broad spectrum of normal expected findings that must be differentiated from early or late complications in which intervention is required. In this article, normal and abnormal postoperative and post-TEVAR/EVAR MDCT findings are described.