The potential effects of radiographic criteria to exclude aortography in patients with blunt chest trauma

Thoracic computed tomography is an effective screening modality in patients with penetrating injuries to the chest

BACKGROUND

The precise role of thoracic CT in penetrating chest trauma remains to be defined. We hypothesized that thoracic CT effectively screens hemodynamically normal patients with penetrating thoracic trauma to surgery vs. expectant management (NOM).

METHODS

A ten-year review of all penetrating torso cases was retrospectively analyzed from our urban University-based trauma center. We included hemodynamically normal patients (systolic blood pressure ≥90) with penetrating chest injuries that underwent screening thoracic CT. Hemodynamically unstable patients and diaphragmatic injuries were excluded. The sensitivity, specificity, positive predictive value and negative predictive value were calculated.

RESULTS

A total of 212 patients (mean injury severity score=24, Abbreviated Injury Score for Chest=3.9) met inclusion criteria. Of these, 84.3% underwent NOM, 9.1% necessitated abdominal exploration, 6.6% underwent exploration for retained hemothorax/empyema, 6.6% underwent immediate thoracic exploration for significant injuries on chest CT, and 1.0% underwent delayed thoracic exploration for missed injuries. Thoracic CT had a sensitivity of 82%, specificity of 99%, positive predictive value of 90%, a negative predictive value of 99%, and an accuracy of 99% in predicting surgery vs. NOM.

CONCLUSIONS

Thoracic CT has a negative predictive value of 99% in triaging hemodynamically normal patients with penetrating chest trauma. Screening thoracic CT successfully excludes surgery in patients with non-significant radiologic findings.

Endovascular intervention in thoracic arterial trauma

The management of thoracic vascular injury has improved dramatically over the past two decades. The availability of multi-row detector CT has facilitated early diagnosis and incorporation of minimally invasive endograft repair for traumatic aortic injury has improved mortality and paraplegia rates. This review evaluates the available data on stent-graft repair of acute blunt traumatic aortic injury and traumatic great vessel injury with regard to safety and efficacy in comparison with conventional open surgical repair.

Diagnosis of blunt traumatic aortic injury 2007: still a nemesis

In recent years, the use of multidetector computed tomography (MDCT) for the diagnosis of acute thoracic injury in blunt trauma has expanded. MDCT has shown high accuracy for the diagnosis or exclusion of injury to the aorta and its primary branches, decreasing the need for thoracic angiography and allowing earlier treatment of this often rapidly fatal lesion. With increasing use of MDCT, more subtle injuries and variants of vascular anatomy are being recognized that create pitfalls in the diagnosis. Of perhaps more concern is the recognition that aortic injury can occur with little or no associated mediastinal hematoma, the principle chest radiographic finding indicating a need for further imaging. The importance of recognizing unusual sites of aortic injury, congenital variants of mediastinal anatomy, the precise extent of injury, and the anatomic pathology present as key factors in deciding among treatment options is emphasized.

Thoracic Vascular Injury

This article emphasizes multirow detector CT (MDCT) technique, the spectrum of findings for diagnosing major thoracic vascular injuries, and the challenges and potential errors that might be encountered. In particular, the role of MDCT data after processing to enhance diagnostic accuracy and convey appropriate and required diagnostic information to the doctors who are managing these vascular injuries are discussed.

Imaging of Acute Thoracic Injury: The Advent of MDCT Screening

Chest radiography remains the primary screening study for the assessment of victims of chest trauma, but computed tomography (CT), particularly multidetector CT (MDCT), has progressively changed the imaging approach to these patients. MDCT acquires thinner sections with greater speed, allowing higher quality axial images and nonaxial reformations than conventional or single-detector helical CT. The speed of MDCT, both in acquiring data and in reconstructing images, makes the performance of total body surveys in the blunt polytrauma patient practicable. In general, CT has been well documented to offer major advantages over chest radiography in both screening for thoracic injuries and in characterizing such injuries. This capacity has been enhanced by the application of multichannel data acquisition. The greater sensitivity of MDCT has been well demonstrated in diagnosing vascular and diaphragmatic injuries. This article reviews current concepts of diagnostic imaging in acute chest trauma from blunt force and penetrating mechanisms emphasizing the spectrum of diagnostic imaging findings for various injuries, based primarily on radiographic and CT appearances. The advantages of MDCT for selected injuries are emphasized.

Review of branch aortic injuries in blunt chest trauma

OBJECTIVES

To review the incidence, mechanisms of injury, diagnosis and treatment of injuries to the major branches of the thoracic aorta within the thoracic cavity following blunt trauma.

METHODS

Medline, Embase and Cochrane were searched using appropriate key word and MeSH headings. Full text articles were retrieved where there was any information relating to the mechanism of injury, incidence of injury, diagnosis, treatment or outcome in patients with injuries to the brachiocephalic, subclavian or carotid arteries within the thoracic cavity following blunt chest trauma.

RESULTS

The reported incidence of these injuries varied widely, most injuries were related to rapid deceleration injuries or falls. Diagnosis depends on a high level of clinic suspicion and appropriate investigations include helical CT scanning and arteriography. Treatment options have expanded in recent years with the use of endovascular stents; however, the optimal treatment remains uncertain.

CONCLUSIONS

Aortic branch injuries must be actively excluded in patients with suspicious mechanisms of injury. Guidelines determining appropriate investigative pathways and methods of treatment should be developed at all trauma centres.

Diagnostic imaging of acute thoracic injury

In recent years, the advent of multidetector CT (MDCT) has begun to change the imaging approach to patients sustaining blunt or penetrating thoracic injury. The ability to directly detect some injuries that are often occult on chest radiography, such as pericardial hemorrhage, major thoracic vascular injury, small pneumothorax, and diaphragm tears, as well as the ability to better define the extent of other injuries, such as lung contusion and laceration, account for this transition. This article reviews current concepts of diagnostic imaging in acute chest trauma from both blunt force and penetrating mechanisms, emphasizing the spectrum of diagnostic imaging findings for various injuries, primarily based on multidetector MDCT.

Chest Radiographs of Limited Utility in the Diagnosis of Blunt Traumatic Aortic Laceration

BACKGROUND

The radiographic diagnosis of blunt traumatic aortic laceration (BTAL) remains problematic. We reviewed our experience with chest radiographic signs of BTAL at a single trauma center.

METHODS

The chest radiographs of 188 consecutive blunt trauma patients with suspected BTAL who underwent portable chest radiography and aortography were retrospectively reviewed by a thoracic radiologist. The presence or absence of 15 radiographic findings were recorded, and the sensitivity and specificity of individual radiographic signs and combinations of signs were determined.

RESULTS

There were 10 patients with BTAL. Although three signs showed greater than 90% sensitivity for BTAL, these signs showed low specificity, and no significant improvement in overall accuracy was achieved by combining radiographic findings.

CONCLUSION

The experience at our institution suggests that chest radiographs have limited utility in the accurate diagnosis of blunt traumatic aortic laceration. Cross-sectional imaging techniques will likely become the preferred imaging procedures for evaluating patients with suspected BTAL.

Guidelines for the diagnosis and management of blunt aortic injury: an EAST Practice Management Guidelines Work Group

In summary, BAI is a lethal result of severe blunt trauma. It should be considered in all patients who sustained injury by a deceleration or acceleration mechanism, especially in the face of physical or radiographic findings suggestive of mediastinal injury. Angiography remains the "gold standard" for diagnosis, although CT scanning is taking more of a role, especially for screening. Diagnosis should be followed by prompt surgical repair using some method of distal perfusion to minimize renal and spinal cord ischemia. If prompt repair is not feasible because of other injuries or comorbidities, medical control of blood pressure is warranted in the interim.

Surgical outcome of traumatic rupture of the thoracic aorta

BACKGROUND

The aim of this study was to point out the results of different techniques of spinal cord protection in surgically-treated patients with traumatic thoracic aorta (TTA).

METHODS

A multicentric study was carried out involving 182 patients with TTA. Four patients died before surgery. Two patients were operated on without any investigation and 2 had no aortic tear at thoracotomy. The remaining 174 patients had aortic isthmus disruption and were included in the study. The mean age was 32.3+/-14.29 years with 126 men (72.4%) and 48 women (27.6%). Road accidents were causal in 163 patients (93.66%); polytraumatism was frequent. A standard chest roentgenogram led to a diagnosis which was confirmed with aortography in 94.8% of cases. Surgical repair of visceral lesions was performed in 52 patients (29.9%) for traumatic spleen, liver, diaphragm, mesentery, and gut. These operations were done before or after aortic operation in 21.3% and 8.6% of cases, respectively. Thirty-three patients (19%) died and 9 (5.2%) had paraplegia. Sixty-nine patients had clamp and sew technique (group 1). Ninety-three patients had different types of extracorporeal circulation (group 2), and 12 patients had Gott shunt (group 3). No difference appeared between the 3 groups according to mortality and paraplegia. But the sex ratio, age, visceral lesions, craniocerebral lesions, the type of aortic repair, and cross-clamp time were discriminative.

RESULTS

The univariate analysis point out age, cross-clamp time, hemothorax, and anatomical type of aortic injury as the risk factors of death. This was confirmed by a multivariable test which retained age, cross-clamp time, and hemothorax as risk factors. When not diagnosed in time, TTA is serious and has a bad prognosis. In spite of a high mortality and morbidity, the surgical management has improved. Immediate operation and medullar protection are the stumbling block in this operation.

CONCLUSIONS

Operation can be delayed in some cases, but one must take care of hemodynamic instability. This calls for a repair of the serious associated lesions first, or of a quick performing of a thoracotomy for ruptured aorta. The question remains, is it better to protect the spinal cord with the lower aortic perfusion and avoid the simple cross-clamp? Clinical studies give few answers to this question, and the best answer has not yet been given, as we lack prospective studies in this field.

Traumatic aortic rupture: delayed presentation with a normal chest radiograph

Traumatic aortic injury is a potentially fatal complication of blunt trauma. Patients with this entity may have a constellation of signs and symptoms and frequently have other significant injuries. The diagnosis is often suspected through abnormalities on the presenting chest radiograph. Delay in diagnosis results in increased morbidity and mortality. This report details the delayed presentation of an ambulatory patient with traumatic aortic rupture and a normal chest radiograph.

Traumatic aortic rupture: diagnosis and management

BACKGROUND

Traumatic aortic rupture is a relatively uncommon lesion that presents the cardiothoracic surgeon with unique challenges in diagnosis and management. To address controversial aspects of this disease, we reviewed our experience.

METHODS

The study was performed by retrospective chart review.

RESULTS

Forty-two patients with traumatic thoracic aortic ruptures were managed between January 1988 and June 1997. Nine arrived without vital signs and died in the emergency department. Admission chest radiographs were normal in 3 patients (12%) and caused significant delays in diagnosis. Four of 30 patients admitted with vital signs had rupture before thoracotomy and died. Twenty-six underwent aortic repair. In 1 patient repair was performed with simple aortic cross-clamping, whereas a second was managed with a Gott shunt. The remaining 24 patients had repair with partial left heart bypass. In 1 patient hypothermic circulatory arrest was required. Two patients (7.7%) died. There were no cases of new postoperative paraplegia in the bypass group. There was no morbidity directly attributable to the administration of heparin for cardiopulmonary bypass.

CONCLUSIONS

In a discrete group of patients with traumatic rupture of the aorta, the rupture will become complete during the first few hours of hospital admission; aggressive medical treatment with beta-blockade and vasodilators in the interval before the operation is an essential aspect of management. Active distal circulatory support with partial left-heart bypass provides the optimal means of preventing spinal cord ischemia during repair of acute traumatic aortic rupture.

Noncorrelation between thoracic skeletal injuries and acute traumatic aortic tear

It is generally accepted that the presence of thoracic skeletal injuries has a predictive value for acute traumatic aortic tear (ATAT). The purpose of this study is to objectively assess the validity of that premise. The initial chest radiographs of 548 patients who underwent aortic angiography for suspected ATAT were reviewed for thoracic skeletal injuries. The incidence of thoracic skeletal injuries was compared between patients with and without angiographically confirmed ATAT. Rib fracture is the only thoracic skeletal injury whose incidence is statistically significantly higher in patients with ATAT (36 of 62, 58.1%) than in those without (207 of 486, 42.6%) (p = 0.0209). The positive predictive value of rib fractures in evaluating ATAT, however, is 14.8%, a rate similar to the incidence of ATAT at most trauma centers, and the specificity is 57.4%. The second most common finding in patients with ATAT, the absence of thoracic skeletal injury, is not statistically significantly different between patients with ATAT (24 of 62, 38.7%) and those without (220 of 486, 45.3%) (p = 0.3279). We conclude that (1) there is no clinically relevant correlation between thoracic skeletal injuries and ATAT, and (2) selection of patients requiring thoracic aortography must be based on appropriate mechanism of injury and radiographic evidence of mediastinal hematoma.

Routine transesophageal echocardiography for the diagnosis of aortic disruption in trauma patients without enlarged mediastinum

OBJECTIVE

To assess the value of routine transesophageal echocardiography (TEE) in diagnosing traumatic disruption of the aorta (TDA) in trauma patients presenting without enlarged mediastinum on chest x-ray films.

DESIGN

Prospective study.

MATERIALS AND METHODS

TEE was routinely performed to exclude the presence of TDA in patients who sustained severe trauma secondary to abrupt deceleration collisions and presented with an upper mediastinum of fewer than 8 cm on supine chest x-ray films. Patients were divided into two groups according to the presence (group I) or absence (group II) of mediastinal hematoma diagnosed during TEE examination. Radiographic signs regarded as indicators of the presence of TDA were evaluated in both groups.

RESULTS

Among the 40 consecutive patients studied, TEE demonstrated two cases of TDA associated with a mediastinal hematoma that were confirmed by both aortography and surgery. One of the patients had a normal mediastinum on presentation chest x-ray films, and the other only exhibited a blurred aortic knob. Radiographic mediastinal abnormalities suggestive of TDA were observed in 13 patients, but chest x-ray films were unremarkable in 12 patients. Twenty patients had multiple rib fractures. The frequency of chest radiographic abnormalities was not significantly higher in group I (n = 6) when compared with group II patients (n = 34). TEE examination demonstrated a normal thoracic aorta in 35 patients and was nondiagnostic in 3 patients (normal aortography).

CONCLUSION

TEE should be routinely performed in victims of violent deceleration collisions, even in patients presenting apparently normal mediastinum on supine chest radiography.

Associated injuries in patients with blunt chest trauma: detection by abdominal roentgenograms after aortography

To determine the value of abdominal roentgenograms after aortography for detecting additional organ injuries, we retrospectively evaluated the abdominal and pelvic roentgenograms after aortography of 170 trauma patients who underwent arch aortography to detect aortic rupture. In 160 (94%) of 170 patients, the results of arch studies were normal. Ten (6%) of 170 patients had aortic rupture (8 patients) or rupture of a major vessel (2 patients). Thirty-one (18%) of 170 patients had associated injuries demonstrated by the roentgenograms taken after aortography, including pelvic or femoral fractures (13%), pelvic hematomas (5.8%), renal injuries (1.1%), and bladder ruptures (2.9%). We conclude that abdominal and pelvic pain roentgenograms should be part of a routine arch aortography performed for blunt chest trauma to detect additional organ injuries that frequently accompany injuries from motor vehicle crashes.

Traumatic lacerations of the aorta and great vessels with a normal mediastinum at radiography

The possibility of a "normal" mediastinum at conventional chest radiography in a patient with a lacerated aorta or great vessel from blunt thoracic trauma has not been evaluated objectively. All 1991 members of the Society of Thoracic Radiology were sent a questionnaire asking for examples of such cases. A similar questionnaire was placed in the newsletter of the Society of Cardiovascular and Interventional Radiology. The literature also was reviewed for cases. Seventy-eight of 327 questionnaires were returned with responses. Eight responders reported 12 examples of a normal mediastinum radiograph in a patient with a lacerated aorta. Review of the same radiographs by the authors yielded three normal and nine subtly abnormal mediastina. One additional normal radiograph was obtained of a patient with a lacerated great vessel. Another 16 cases of lacerated aortae (n = 12) and great vessels (n = 4) in patients with normal mediastina were found through a literature search; images from three of these were reviewed by the authors. Although this is an infrequent event, the mediastinum can be normal at plain chest radiography with traumatic lacerations of the aorta and great vessels.

Right atrial rupture due to blunt trauma: CT evaluation

Controversy currently exists over the use of CT versus aortography in initial evaluation of blunt chest trauma. A case is described in which CT expeditiously diagnosed cardiac rupture and ruled out aortic trauma.

The normal mediastinum in blunt traumatic rupture of the thoracic aorta and brachiocephalic arteries

In a review of 52 articles, published between 1953 and 1989, 656 patients with blunt traumatic rupture of the thoracic aorta or brachiocephalic arteries were identified. Of these, 608 (92.7%) had an abnormal mediastinum on initial chest radiographs obtained in the emergency department, thus allowing early detection of the vascular injury. Unfortunately, 48 (7.3%) of these patients had a normal mediastinum on their initial chest radiographs. This appears to occur when the traumatic pseudoaneurysm is not accompanied by associated mediastinal hemorrhage or hematoma formation, and the pseudoaneurysm is either small or is situated in such a way that it does not alter the mediastinal contour. The use of accessory clinical and radiographic signs to indicate the need for aortography has been shown to be of very low yield, but would have allowed the early detection of an additional 5.6% of the reported cases. Performing aortography solely on the basis of a history of major decelerating blunt trauma to the thorax remains the only way, in the acute emergency department setting, to detect the 1.7% of patients with aortic or brachiocephalic arterial rupture who have no mediastinal abnormality or accessory clinical or radiographic signs of vascular injury. There is evidence from the literature, however, to suggest that the evaluation of serial chest radiographs obtained at close intervals for the first month following trauma for the development of mediastinal abnormality or large hemothorax is an acceptable alternative to the routine performance of aortography in those blunt chest trauma victims with no clinical or radiographic suspicion of vascular injury.