Minimal Aortic Injury: Mechanisms, Imaging Manifestations, Natural History, and Management

The enigma of fine mobile structures on the aortic surface in a patient undergoing transcatheter aortic valve replacement: a case report

Background

The surface of the aorta generally does not show motion unless mobile atheroma, thrombi, vegetations, or intimal flaps are present. We previously described unusual mobile filamentous structures in the carotid artery. Here, we describe similar findings in the aorta and their possible cause.

Case summary

An 88-year-old female with progressive exertional dyspnoea and severe aortic stenosis had a successful transcatheter aortic valve replacement (TAVR). A filamentous structure was noted on the focused pre-operative 2D transoesophageal echocardiography in the proximal descending aorta and post-TAVR as long strand-like structures attached to the thickened intimal wall with a planar component on 3D imaging. These findings were not associated with symptoms or clinical sequelae on short- and long-term follow-up.

Discussion

The mobile structures that we describe are atypical for atheroma, thrombi, vegetations, and dissections in terms of their form and clinical presentation. 2D imaging showed that the filaments had focal thickening and emerged from the aortic surface. These findings suggest a relationship with the intima, perhaps from atherogenesis or injury with disruption or lifting of the intimal surface. No clinical sequelae were detected that may also relate to their position in the descending aorta and not the arch.

CT angiography of non-aortic thoracic arterial trauma

While aortic injury is the most commonly cited thoracic arterial injury, non-aortic arterial injuries represent an uncommon but significant source of morbidity and mortality in blunt and penetrating thoracic trauma patients. Knowledge of the spectrum of vascular injury and anatomic considerations that dictate patterns of associated thoracic hemorrhage will assist the radiologist in the accurate and efficient diagnosis of these injuries. This article provides a review of anatomy, pertinent clinical exam and CT angiography findings, as well as therapeutic options for non-aortic thoracic arterial trauma.

Endovascular treatment of a traumatic thoracic pseudo-aneurysm in a pediatric patient: a case report with review of literature

Blunt aortic injury (BAI) as a result of thoracic trauma is a rare entity in the adult and pediatric population. The endovascular approach has been the preferred method of management over operative repair in adults. However, data on pediatrics is limited to case reports and case series with no long-term follow-up. There are no current guidelines for management in the pediatric population. We are reporting a successful repair of a traumatic thoracic aortic aneurysm in a 13 year old boy with covered stents, with a review of relevant literature.

Blunt Thoracic Aortic Injury

Blunt thoracic aortic injury (BTAI) is a potentially fatal condition that needs prompt recognition and expedited management. Clinical manifestations of BTAI are not straight forwarding and may be misdiagnosed. The grade of aortic injury is an important determinant of perioperative mortality and morbidity, as well as the indication of treatment, along with the presence of concomitant lesions of other involved organs. The mainstay of treatment nowadays for hemodynamically stable patients who survive the trauma scene is represented by delayed endovascular repair whenever anatomically and clinically feasible. Endovascular repair, in fact, is burdened by lower perioperative mortality and morbidity rates if compared to open surgical repair, but concerns remain about the need for long-term surveillance and radiation exposure in patients who are at a younger age than patients treated for the aneurysmal disease. The aim of the paper is to provide an update on the diagnostic modalities and strategies of treatment for patients affected by BTAI.

Minimal Aortic Injury Detected on Computed Tomography Angiography during Initial Trauma Imaging: Single Academic Level 1 Trauma Center Experience

BACKGROUND

 Minimal aortic injury (MAI), a subtype of acute traumatic aortic injury, is being increasingly recognized with better imaging techniques. Given conservative management, the role of follow-up imaging albeit important yet has to be defined.

METHODS

 All trauma chest computed tomography angiographies (CTAs) at our center between January 2012 and January 2019 were retrospectively reviewed for presence of MAI. MAIs were generally reimaged at 24 to 72 hours and then at a 7- and 30-day interval. Follow-up CTAs were reviewed for stability, progression, or resolution of MAI, along with assessment of injury severity scores (ISS) and concomitant injuries, respectively.

RESULTS

 A total of 17,569 chest CTAs were performed over this period. Incidence of MAI on the initial chest CTA was 113 (0.65%), with 105 patients receiving follow-up CTAs. The first, second, third, and fourth follow-up CTAs were performed at a median of 2, 10, 28, and 261 days, respectively. Forty five (42.9%), 22 (21%), 5 (4.8%), and 1 (1%) of the MAIs were resolved by first, second, third, and fourth follow-up CTAs. Altogether, 21 patients showed stability (mean ISS of 16.6), and 11 demonstrated improvement (mean ISS 25.8) of MAIs. Eight patients had no follow-up CTA (mean ISS 21). No progression to higher-grade injury was observed. Advancing age decreased the odds of MAI resolution on follow-up. A possible trend (p-value 0.22) between increasing ISS and time to resolution of MAIs was noted.

CONCLUSION

 In our series of acute traumatic MAIs diagnosed on CTA imaging, there was no progression of injuries with conservative management, questioning the necessity of sequential follow-up imaging.

Natural history and clinical significance of aortic focal intimal flaps

Objective

Focal intimal flaps (FIF) are a variety of defects of the aorta that result in a short, flap-like projection into the lumen, and are often encountered in asymptomatic patients undergoing computed tomography angiography (CTA) surveillance for aortic aneurysm, but the natural history and clinical significance of such lesions has not yet been studied.

Methods

We retrospectively identified patients with an asymptomatic FIF and available imaging follow-up (>1 year). FIF was defined as flap-like intimal irregularity < 4 cm in length involving the thoracic aorta (TA), abdominal aorta (AA) or common iliac arteries (CIA). FIF characteristics included length and circumferential extent as well as the presence and size (width and depth) of associated penetrating aortic ulcers (PAUs). Patient characteristics, adverse events and history of surgical repair was determined by chart review. FIFs and associated PAUs were assessed for progression by comparing baseline and follow-up CTA studies.

Results

A total of 84 FIFs were identified in 77 patients. Average age was 69.2 ± 10.1 years, and 81% were male (81%). Common co-morbidities included: hypertension (78%), hyperlipidemia (68%), smoking (60%), coronary artery disease (41%), aortic aneurysm (34%), type II diabetes mellitus (27%) and prior cardiovascular surgery (25%). FIFs were most commonly located in the abdominal aorta (n = 50, 60%). Nearly all FIFs were associated with local atherosclerotic plaque (93%). Mean follow-up interval was 3.5 ± 2.6 years (259 cumulative follow-up years). Change in FIF length and local aortic diameter over follow-up were 0.7 ± 2.3 mm and 0.8 ± 1.1 mm, respectively. Nearly half (47%) of FIFs were associated with penetrating aortic ulcers (PAU) with baseline depth of 7.3 mm (IQR: 6.1–10.2) and change in depth of 0.5 ± 1.4 mm. Only 12% of FIFs and 0% of associated PAUs demonstrated growth (≥3 mm) at follow-up. No acute pathology developed in the location of FIFs and no aortic interventions were performed specifically to treat FIFs.

Conclusion

Focal intimal flaps identified in asymptomatic patients with aortic disease were co-localized with atherosclerotic plaque and PAUs, and demonstrated indolent behavior, not leading to significant growth or acute aortic events, supporting a conservative management approach.

Percutaneous Radiofrequency Ablation to Occlude the Thoracic Duct: Preclinical Studies in Swine for a Potential Alternative to Embolization

PURPOSE

To investigate the feasibility of percutaneous radiofrequency ablation (RFA) to occlude the thoracic duct (TD) in a swine model with imaging and histologic correlation.

MATERIALS AND METHODS

Six swine underwent TD RFA. Two terminal (4 hours; 1 open, 1 percutaneous) and four survival (30 days; all percutaneous) studies were performed. Two 20-gauge needles were placed adjacent to the TD under direct visualization after right thoracotomy or under fluoroscopic guidance using a percutaneous transabdominal approach after intranodal lymphangiography. Radiofrequency electrodes were advanced through the needles and ablation was performed at 90 degrees Celsius for 90 seconds. Lymphangiography was performed and the TD and adjacent structures were resected and examined microscopically at the end of each study period.

RESULTS

Four of six subjects survived the planned study period and underwent follow up lymphangiography. Two subjects in the survival group were euthanized early; 1 after developing an acute chylothorax and 1 due to gastric volvulus 14 days after ablation. Occlusion of the targeted TD segment was noted on lymphangiography in 3 of 4 remaining subjects (2 acute, 1 survival). Histology 4 hours after RFA demonstrated necrosis of the TD wall and hemorrhage within the lumen. Histology at 14 and 30 days revealed fibrosis with hemosiderin laden macrophages replacing the ablated TD. Collagen degeneration within the aortic wall involving a maximum of 60% thickness was noted in 5/6 subjects.

CONCLUSION

Percutaneous RFA can achieve short-segment TD occlusion. Further study is needed to improve safety and demonstrate clinical efficacy in treating TD leaks.

CT features of blunt abdominal aortic injury: an infrequent but life-threatening event

Blunt injury to the abdominal aorta is a rare but potentially fatal event. Despite being much less common than thoracic aorta involvement, it carries high morbidity and mortality. Computed tomography (CT) has become the standard method for evaluating the trauma patient and can provide a rapid accurate diagnosis of aortic injury. Depending on the magnitude of the traumatic forces, aortic injuries may be present in blunt abdominal trauma and appear as a spectrum of disease ranging from small intraluminal defects to full-thickness circumferential ruptures. We classify lesions into four groups as it has been reported in the literature: intimal flap (grade I), intramural hematoma (grade II), pseudoaneurysm (grade III), and rupture (grade IV). Radiologists play a crucial role in the evaluation and care of these patients since imaging findings significantly affect clinical management. The purpose of this paper is to describe the different types of traumatic injury to the abdominal aorta, highlighting the key imaging findings on computed tomography (CT).