The utility of chest X-ray as a screening tool for blunt thoracic aortic injury

Diagnosing aortic dissection: A review of this elusive, lethal diagnosis

Aortic dissection (AD) remains a difficult diagnosis in the emergency setting. Despite its rare occurrence, it is a life-threatening pathology that, if missed, is typically fatal. Previous studies have documented minimal improvement in timely and accurate diagnoses despite the advancement of computed tomography. Previous literature has highlighted aortic dissections as a major cause of serious misdiagnosis-related harm. The aim of this article is to review the available literature on AD, discussing the diversity in presentations and the prevalence of historical and exam features to better aid in the diagnosis of AD. AD remains a difficult diagnosis, even with the widespread prevalence of computed tomography angiography usage. No single feature of the history or physical examination is enough to raise suspicion. The diagnosis should be strongly considered in any patient with chest pain that is severe and unexplained by other findings or testing. Those who do not present with acute pain are often complicated by neurologic deficits, hypotension, or syncope. These patients suffer from a change in mental status limiting their ability to participate in the history and physical examination and have a higher rate of complications and mortality. An educated understanding of the atypical presentations of aortic dissection helps the clinician to realistically rank it on the differential diagnosis, culminating in judicious use of definitive imaging.

Significant variation in computed tomography imaging of pregnant trauma patients: a retrospective multicenter study

PURPOSE

Following motor vehicle collisions (MVCs), patients often undergo extensive computed tomography (CT) imaging. However, pregnant trauma patients (PTPs) represent a unique population where the risk of fetal radiation may supersede the benefits of liberal CT imaging. This study sought to evaluate imaging practices for PTPs, hypothesizing variability in CT imaging among trauma centers. If demonstrated, this might suggest the need to develop specific guidelines to standardize practice.

METHODS

A multicenter retrospective study (2016-2021) was performed at 12 Level-I/II trauma centers. Adult (≥18 years old) PTPs involved in MVCs were included, with no patients excluded. The primary outcome was the frequency of CT. Chi-square tests were used to compare categorical variables, and ANOVA was used to compare the means of normally distributed continuous variables.

RESULTS

A total of 729 PTPs sustained MVCs (73% at high speed of ≥ 25 miles per hour). Most patients were mildly injured but a small variation of injury severity score (range 1.1-4.6, p < 0.001) among centers was observed. There was a variation of imaging rates for CT head (range 11.8-62.5%, p < 0.001), cervical spine (11.8-75%, p < 0.001), chest (4.4-50.2%, p < 0.001), and abdomen/pelvis (0-57.3%, p < 0.001). In high-speed MVCs, there was variation for CT head (12.5-64.3%, p < 0.001), cervical spine (16.7-75%, p < 0.001), chest (5.9-83.3%, p < 0.001), and abdomen/pelvis (0-60%, p < 0.001). There was no difference in mortality (0-2.9%, p =0.19).

CONCLUSION

Significant variability of CT imaging in PTPs after MVCs was demonstrated across 12 trauma centers, supporting the need for standardization of CT imaging for PTPs to reduce unnecessary radiation exposure while ensuring optimal injury identification is achieved.

Is Chest X-Ray a Reliable Screening Tool for Blunt Thoracic Aortic Injury? Results from the American Association for the Surgery of Trauma/Aortic Trauma Foundation Prospective Blunt Thoracic Aortic Injury Registry

BACKGROUND

Traditional teaching continues to espouse the value of initial trauma chest x-ray (CXR) as a screening tool for blunt thoracic aortic injury (BTAI). The ability of this modality to yield findings that reliably correlate with grade of injury and need for subsequent treatment, however, requires additional multicenter prospective examination. We hypothesized that CXR is not a reliable screening tool, even at the highest grades of BTAI.

STUDY DESIGN

The Aortic Trauma Foundation/American Association for the Surgery of Trauma prospective BTAI registry was used to correlate initial CXR findings to the Society for Vascular Surgery injury grade identified with computed tomographic angiography.

RESULTS

We analyzed 708 confirmed BTAI injuries with recorded CXR findings and subsequent computed tomographic angiography injury characterization from February 2015 to August 2021. The presence of any of the classic CXR findings was observed in only 57.6% (408 of 708) of injuries, with increasing presence correlating with advanced Society for Vascular Surgery BTAI grade (39.1% [75 of 192] of grade 1; 55.6% [50 of 90] of grade 2; 65.2% [227 of 348] of grade 3; and 71.8% [56 of 78] of grade 4). The most consistent single finding identified was widened mediastinum, but this was only present in 27.7% of all confirmed BTAIs and only 47.4% of G4 injuries (7.8%% of grade 1, 23.3%, of grade 2, 35.3% of grade 3, and 47.4% of grade 4).

CONCLUSIONS

CXR is not a reliable screening tool for the detection of BTAI, even at the highest grades of injury. Further investigations of specific high-risk criteria for screening that incorporate imaging, mechanism, and physiologic findings are warranted.

Thoracic Trauma: Aortic Injuries

Thoracic aortic injuries caused by high impact trauma are life-threatening and require emergent diagnosis and management. With improvement in the acute care services, an increasing number of such injuries are being managed such that patients survive to undergo definitive therapies. A high index of clinical suspicion is required to order appropriate imaging. Computed tomography angiography is used to classify the injuries and guide treatment strategy. While low-grade injuries might be managed conservatively, high-grade injuries require urgent surgical or endovascular intervention. Over the past decade, endovascular repair of the thoracic aorta with or without a surgical bypass has become the preferred treatment with reduced mortality and morbidity. Rapid advancements in the stent graft technology have reduced the anatomic barriers to endovascular therapy and increased the confidence of the operators. Detailed planning prior to the procedure, understanding of the anatomy, correct choice of hardware, and adherence to technical protocol are essential for a successful endovascular procedure. These patients are often young and the limited data on the long-term outcome of aortic stent grafts make a case for a robust follow-up protocol.

Blunt thoracic aorta injuries, an Australian single centre's perspective

BACKGROUND

Blunt thoracic aortic injuries (BTAI) are potentially life-threatening emergencies. The management paradigm has shifted from open repair to a predominantly endovascular approach. We evaluated the trends in managing BTAI at our centre over the last decade and compared them to current international guidelines.

METHODS

We retrospectively reviewed all patients who presented with BTAI to our level one trauma centre, Westmead Hospital, New South Wales, Australia between 1 January 2010 and 31 December 2019. Patient demographics, injury grade and location, imaging features, management details and outcomes were analysed.

RESULTS

BTAI is rare, with 39 patients identified at our institute over the last 10 years. Of these, seven died in the emergency department from their associated injuries (17.9%). Of the 32 survivors, 27 underwent surgical management with an endovascular stent-graft placement, and the remaining five patients were treated non-operatively. No patients were treated via an open surgical approach. All patients were diagnosed via computed tomography angiography. There were one death and two endoleaks amongst patients who underwent Thoracic endovascular aortic repair (TEVAR). The death occurred secondary to severe traumatic brain injury. Two patients illustrated neurological changes however these were associated with the original injury. No patients failed non-operative management.

CONCLUSION

This study demonstrates that at our level one trauma centre, patients with BTAI are managed in accordance with international guidelines. All patients underwent computed tomography angiography for diagnosis and grading of injury. All patients requiring surgical management underwent TEVAR. Furthermore, our data support that select patients with grade I injuries can safely be managed non-operatively.

Blunt Thoracic Aortic Injury and Acute Trauma: The Effect on Aortic Diameter and the Consequences for Stent-graft Sizing

BACKGROUND

Blunt thoracic aortic injury (BTAI) is associated with a high mortality and large trauma burden. Trauma and resuscitation after injury affect cardiovascular status, which may in turn affect aortic diameter. Measurement of aortic diameter is necessary to guide stent-graft sizing as part of BTAI management. Inaccurate measurement may lead to stent-graft complications. This pilot study aimed to assess the effect of acute major trauma on stent-graft sizing and stent-graft complications, in the context of BTAI and to assess whether any effect could be predicted.

METHODS

Patients who were admitted to a UK major trauma center between January 2007 and December 2017, and were diagnosed with BTAI, were identified. The thoracic aortic diameter was measured at six points on initial and surveillance computed tomography imaging. Data on patient demographics, admission heart rate, mean arterial pressure (MAP), and serum lactate were gathered.

RESULTS

Thirty-two patients were identified. Twenty met inclusion criteria. Of these, 12 were managed operatively and eight nonoperatively. The mean age was 40, the mean injury severity score was 43, and 85% were male. A mean increase in diameter between initial trauma scan and surveillance scan was noted throughout the thoracic aorta (P < 0.05). Stent-graft oversizing relative to aortic diameter changed significantly from initial trauma imaging to surveillance imaging (P < 0.05). Admission heart rate, MAP, and serum lactate were not predictive of the percentage change in aortic diameter. There were no complications at surveillance imaging (mean 45 days) or during medium term follow-up (mean 532 days).

CONCLUSIONS

Aortic diameter is affected by BTAI, acute major trauma, and resuscitation in a significant and variable manner. Measurements of the aorta in a patient with BTAI in the acute trauma setting should be viewed with uncertainty. A lack of complications in the short term is suggestive of a wide tolerance range regarding stent-graft sizing, but long-term results are unknown.

Die traumatische Aortenruptur

Verkehrsunfälle sind für den größten Teil der traumatischen Aortenrupturen verantwortlich, meist zusammen mit weiteren schweren Begleitverletzungen. Die prähospitale Sterblichkeit ist hoch. Bei Verdacht auf eine beteiligte Aortenverletzung, aufgrund eines hohen traumatic aortic injury scores, ist eine Computertomographie durchzuführen. Es erfolgt eine Triage der Verletzungen, und die Versorgungspriorität der Aorta richtet sich nach dem Schweregrad der Aorten- und Begleitverletzungen sowie dem Zustand des Patienten. Bis zur definitiven Versorgung der aortalen Läsion muss der Blutdruck konsequent gesenkt werden. Grad I und II können in Einzelfällen unter enger Kontrolle inital konservativ gemanagt werden. Grad III (gedeckte Ruptur) und Grad IV (freie Ruptur) benötigen eine raschestmögliche Versorgung (interventionell, chirurgisch). In ausgesuchten Fällen kann auch eine verzögerte Versorgung günstig sein.

Als bevorzugte Versorgungsform hat sich die interventionelle Stentgrafttherapie etabliert.

Blunt Thoracic Aortic Injury: Current Therapies, Outcomes, and Challenges

Blunt thoracic aortic injuries are rare occurrences but carry an increased risk of mortality. Over the last two decades, however, major advances in diagnostic imaging, staging, and treatment have significantly improved outcomes. Modern imaging paved the way for a new staging system based on the anatomical layers of the aortic wall. This staging system, in turn, allowed for refinement of treatment, which now includes nonoperative management with anti-impulse therapy, endovascular intervention, and, if needed, open surgical repair. As is the case with any other rapidly evolving therapy, however, new challenges and controversies arise. The resolution of these challenges will rely on a broad, international, and multidisciplinary effort. (This is a review article based on the invited lecture of the 46th Annual Meeting of Japanese Society for Vascular Surgery.)

Is endovascular repair the first choice for all blunt aortic injury? A real-world assessment

Blunt thoracic aortic injury (BTAI) represents an infrequently encountered but lethal traumatic injury. Minimal aortic injuries are appropriately treated by medical management, while more severe injuries require endovascular or open repair. Rapidly evolving endovascular technology has largely supplanted open repair as first line operative intervention, however, the complexity of the severely injured blunt trauma patient can complicate management decisions. The development and implementation of an optimal consensus grading system and treatment algorithm for the management of BTAI is necessary and will require multi-institutional study.

Chinese expert consensus on echelons treatment of thoracic injury in modern warfare

The emergency treatment of thoracic injuries varies of general conditions and modern warfare. However, there are no unified battlefield treatment guidelines for thoracic injuries in the Chinese People's Liberation Army (PLA). An expert consensus has been reached based on the epidemiology of thoracic injuries and the concept of battlefield treatment combined with the existing levels of military medical care in modern warfare. Since there are no differences in the specialized treatment for thoracic injuries between general conditions and modern warfare, first aid, emergency treatment, and early treatment of thoracic injuries are introduced separately in three levels in this consensus. At Level I facilities, tension pneumothorax and open pneumothorax are recommended for initial assessment during the first aid stage. Re-evaluation and further treatment for hemothorax, flail chest, and pericardial tamponade are recommended at Level II facilities. At Level III facilities, simple surgical operations such as emergency thoracotomy and debridement surgery for open pneumothorax are recommended. The grading standard for evidence evaluation and recommendation was used to reach this expert consensus.

To reduce routine computed tomographic angiography for thoracic aortic injury assessment in level II blunt trauma patients using three mediastinal signs on the initial chest radiograph: a preliminary report

PURPOSE

CTA is routinely ordered on level II blunt thoraco-abdominally injured patients for assessment of injury to the thoracic aorta. The vast majority of such assessments are negative. The question being asked is, Does the accurate interpretation of the three mediastinal signs permit reliable determination of which patients need CTA for aortic assessment? The purpose of this investigation was to evaluate the role of three specifically selected mediastinal anatomic signs on the initial supine chest radiograph (CXR) of adult level II blunt thoraco-abdominally injured patients for the presence or absence of a mediastinal hematoma. The presence of a mediastinal hematoma is typically used as an indicator for computed tomographic angiography (CTA). The three mediastinal signs are the right para-tracheal stripe (RPTS), left para-spinal line (LPSL), and the left apical extra-pleural area (LAPA).

MATERIALS AND METHODS

The patient triage designation (level II trauma) was made by the attending physician at the time of admission. The initial CXR image and the CTA report of the 197 adult blunt level II thoraco-abdominally injured patients obtained on the day of admission were compared. The CXR of each of the 197 patients was independently assessed by each of four observers specifically for the status of the three mediastinal signs. Each observer was blinded to the CTA report until after the status of the three mediastinal sign evaluation had been determined. Two or three of the mediastinal signs being positive were required to determine that the CXR was positive for a mediastinal hematoma.

RESULTS

Two or three of the selected mediastinal signs were normal in 192 (97.5%) patients. None of these patients had either a mediastinal hematoma or a major aortic injury on CTA. In each of the remaining five (2.5%) patients, two or three of the mediastinal signs were abnormal. Each of these patients had a mediastinal hematoma and a major thoracic aortic injury on CTA.

CONCLUSIONS

This preliminary study suggests that the accurate interpretation of the three specifically selected mediastinal signs on the initial supine CXR of adult level II blunt thoraco-abdominally injured patients could reduce the need for routine CTA for thoracic aortic injury assessment, and requires verification by an additional study.

Nonoperative management rather than endovascular repair may be safe for grade II blunt traumatic aortic injuries: An 11-year retrospective analysis

BACKGROUND

The Society of Vascular Surgery (SVS) guidelines currently suggest thoracic endovascular aortic repair (TEVAR) for grade II-IV and nonoperative management (NOM) for grade I blunt traumatic aortic injury (BTAI). However, there is increasing evidence that grade II may also be observed safely. The purpose of this study was to compare the outcome of TEVAR and NOM for grade I-IV BTAI and determine if grade II can be safely observed with NOM.

METHODS

The records of patients with BTAI from 2004 to 2015 at a Level I trauma center were retrospectively reviewed. Patients were separated into two groups: TEVAR versus NOM. All BTAIs were graded according to the SVS guidelines. Minimal aortic injury (MAI) was defined as BTAI grade I and II. Failure of NOM was defined as aortic rupture after admission or progression on subsequent computed tomography (CT) imaging requiring TEVAR or open thoracotomy repair (OTR). Statistical analysis was performed using Mann-Whitney U and χ tests.

RESULTS

A total of 105 adult patients (≥16 years) with BTAI were identified over the 11-year period. Of these, 17 patients who died soon after arrival and 17 who underwent OTR were excluded. Of the remaining 71 patients, 30 had MAI (14 TEVAR vs. 16 NOM). There were no failures in either group. No patients with MAI in either group died from complications of aortic lesions. Follow-up CT imaging was performed on all MAI patients. Follow-up CT scans for all TEVAR patients showed stable stents with no leak. Follow-up CT in the NOM group showed progression in two patients neither required subsequent OTR or TEVAR.

CONCLUSIONS

Although the SVS guidelines suggest TEVAR for grade II-IV and NOM for grade I BTAI, NOM may be safely used in grade II BTAI.

LEVEL OF EVIDENCE

Therapeutic study, level IV.

Blunt Trauma of the Aorta, Current Guidelines

Blunt thoracic aortic injury remains a major cause of prehospital deaths. For patients who reach the hospital alive, diagnosis and management have undergone dramatic changes over the last 50 years. Computed tomography scanning is the imaging modality of choice for injury diagnosis and repair planning. Medical management with antihypertensives dramatically decreases the risk of rupture, allowing for delayed repair, while abnormal physiology and more immediately life-threatening injuries can be addressed. Endovascular techniques and endograft technology have reduced significantly the risks associated with repair. However, the incidence of late complications associated with the devices currently available is not known.

Identifying potential utility of resuscitative endovascular balloon occlusion of the aorta: An autopsy study

BACKGROUND

Resuscitative thoracotomy (RT) has been the standard therapy in patients with acute arrest due to hemorrhagic shock. However, with the development of resuscitative endovascular balloon occlusion of the aorta (REBOA), its role as a potential adjunct to a highly morbid intervention such as RT is being discussed. The aim of this study was to identify patients who most likely would have potentially benefited from REBOA use based on autopsy findings.

METHODS

We performed a 4-year retrospective review of all RTs performed at our Level I trauma center. Patients with in-hospital mortality and who underwent subsequent autopsies were included. Patients were divided into blunt and penetrating trauma with and without thoracic injuries. Autopsy reports were reviewed to identify vascular and solid organ injuries. Outcome measure was potential benefit with REBOA. Potential benefit with REBOA was defined based on the ability to safely deploy REBOA. In patients without cardiac, aortic, and major pulmonary vasculature injuries, REBOA was considered potentially beneficial. In all other patients, it was considered as nonbeneficial.

RESULTS

A total of 98 patients underwent an RT, of whom 87 had subsequent autopsies and were reviewed. The mean age was 35.25 (SD, 17.85) years, mean admission systolic blood pressure was 51.38 (SD, 70.11) mm Hg, median Injury Severity Score was 29 (interquartile range [IQR], 25-42), and 44 had penetrating injury. Resuscitative endovascular balloon occlusion of the aorta would have been potentially beneficial in 51.2% of patients (22 of 43 patients) with blunt mechanism of trauma, whereas REBOA would have been potentially beneficial in 38.6% of patients (17 of 44 patients) with penetrating mechanism of trauma. A subgroup analysis showed that REBOA use would have been potentially beneficial in 50.0% of blunt thoracic and 33.3% of penetrating thoracic trauma patients.

CONCLUSIONS

There are a great enthusiasm and premature efforts to introduce REBOA as an alternative to RT. While there exists a great potential for benefit with REBOA use in the management of noncompressible torso hemorrhage, the current indications for REBOA need to be defined better. Patients with penetrating chest trauma in extremis should be considered an absolute contraindication for REBOA use. The majority of patients with blunt trauma in extremis may potentially benefit from REBOA. However, better criteria will help increase these patients who may potentially benefit from REBOA placement.

LEVEL OF EVIDENCE

Therapeutic study, level V.