Role of CT in diagnosis of major arterial injury after blunt thoracic trauma

The role of computed tomography (CT) in the diagnosis of blunt thoracic vascular injury is controversial. Several recent reports have advocated the use of CT to exclude aortic and major branch injuries in hemodynamically stable patients with blunt trauma. This approach potentially avoids invasive angiography and unnecessary treatment delays in multiply injured patients but risks missed aortic transections if the CT or its interpretation is not accurate. We prospectively evaluated 153 consecutive trauma patients in whom we suspected blunt aortic injury between September 1985 and August 1988. All hemodynamically stable patients underwent contrast-enhanced chest CT followed by immediate aortic arch angiography. Forty-nine unstable patients underwent immediate angiography without chest CT, and 11 (22%) had major thoracic arterial injuries. Data from the remaining 104 stable patients indicate that the sensitivity of chest CT for diagnosis of major thoracic injury is 55%; specificity, 65%. If the chest CT had been used as a screening modality to perform aortic angiography, two transected aortas and three major aortic branch injuries would have been missed. We conclude that chest CT has no screening role in the evaluation of blunt trauma patients with possible major vascular injury.     

Role of angiography in the detection of aortic branch vessel injury after blunt thoracic trauma.

PURPOSE: The occurrence of aortic arch branch vessel injury as an isolated occurrence or in association with aortic injury after blunt chest trauma has not been emphasized in the literature. The imaging evaluation is also controversial. METHODS: We reviewed thoracic aortograms of 166 patients examined at our institution from May 1995 to May 1999 performed after blunt thoracic trauma. We evaluated the aortograms for aortic and arch branch vessel injuries. Twenty-four injuries were detected and all patients had either a wide mediastinum demonstrated on plain radiographs (22 patients) or mechanism of injury conducive to aortic injury. RESULTS: Of the 166 patients, 24 (14%; 16 men, 8 women; mean age, 50 years) had aortic or arch branch vessel injuries. Isolated aortic injury occurred in 15 (9%) of 166 patients. Branch vessel injury occurred in 9 (5%) of 166 patients; seven patients (10 branch vessels) had isolated branch vessel injury and two patients (three branch vessels) had branch vessel injury associated with aortic injury. The injured branch vessels were brachiocephalic artery (four), left common carotid artery (four), left subclavian artery (three), right internal mammary artery (one), and left vertebral artery (one). The types of branch vessel injuries included intimal tears (nine vessels; 69%), and transection causing a pseudoaneurysm (four vessels; 31%). Revised Trauma Scores in patients with branch vessel injuries were 12 in seven patients and 11 and 4 in one each. CONCLUSION: We emphasize the angiographic findings in these patients that can at times be quite subtle. Awareness of the incidence of such injuries either in isolation or associated with aortic injury has implications regarding evaluation of this patient population with less invasive techniques such as CT or transesophageal echocardiography.     

Emergency operation for traumatic thoracic aortic rupture diagnosed by enhanced chest computed tomography; report of a case

Thoracic aortic injury caused by blunt chest trauma is often fatal. Although aortography had been inevitable for thoracic surgery until recently, image of computed tomography (CT) is often superior to aortogram nowadays. We present a case of 64-yaer-old man with blunt chest trauma by traffic accident, who was successfully diagnosed and operated without invasive aortography. Thoracic aortic rupture was suspected by plain chest X-ray. His enhanced CT showed the localized leakage of contrast media near the arterial ligament of aortic arch. Because his condition was critically ill, operation was performed immediately without aortography. There found Y-shaped tear at the distal aortic arch, and was replaced with a prosthetic graft. Operation was performed under left heart bypass using heparin-coated circuit and centrifugal pump. We would stress that the enhanced chest CT is sufficiently diagnostic in thoracic aortic trauma like the present case.     

Computed tomography as a screening exam in patients with suspected blunt aortic injury.

BACKGROUND: Chest computed tomography (CT) screening of patients with blunt trauma for thoracic aortic injury is controversial. This study was undertaken to determine whether CT could exclude aortic injury and be used to select patients for aortography. METHODS: Computed tomography and aortography were used to evaluate 155 patients with blunt trauma. Computed tomography scans were reviewed separately by four attending radiologists who were unaware of the patients' clinical course and angiographic findings. RESULTS: Eight of 155 patients had aortic injuries requiring operation. Computed tomography scans in five patients were read as positive by all reviewers. One scan was read as positive by three reviewers and as negative by one. Two scans were read as positive by two radiologists and as negative by two. After poor scans were excluded, the combined sensitivity of CT for detecting aortic injury was 88%, specificity was 54%, positive predictive value was 9%, and negative predictive value 99%. CONCLUSIONS: The sensitivity of CT scan for indicating the need for aortography is observer dependent. As CT manifestations of aortic injury are often subtle, CT does not reliably exclude aortic injury.     

Comparison of multiplane transesophageal echocardiography and contrast-enhanced helical CT in the diagnosis of blunt traumatic cardiovascular injuries

BACKGROUND: Multiplane transesophageal echocardiography (TEE) and helical computed tomography (CT) of the chest have been validated separately against aortography for the diagnosis of acute traumatic aortic injuries (ATAI). However, their respective diagnostic accuracy in identifying blunt traumatic cardiovascular lesions has not been compared. METHODS: During a 3-yr period, 110 consecutive patients with severe blunt chest trauma (age: 41 +/- 17 yr; injury severity score: 34 +/- 14) prospectively underwent TEE and chest CT as part of their initial evaluation. Results of both imaging methods were interpreted independently by experienced investigators and subsequently compared. All cases of subadventitial acute traumatic aortic injury were surgically confirmed. RESULTS: Seventeen patients had vascular injury and 11 had cardiac lesions. TEE and CT identified all subadventitial disruptions involving the aortic isthmus (n = 10) or the ascending aorta (n = 1) that necessitated surgical repair. In contrast, CT only depicted one disruption of the innominate artery. TEE detected injuries involving the intimal or medial layer, or both, of the aortic isthmus in four patients with apparently normal CT results who underwent successful conservative treatment. All cardiac injuries but two were identified only by TEE. CONCLUSIONS: In patients with severe blunt chest trauma, TEE and CT have similar diagnostic accuracy for the identification of surgical acute traumatic aortic injuy. TEE also allows the diagnosis of associated cardiac injuries and is more sensitive than CT for the identification of intimal or medial lesions of the thoracic aorta.     

Traumatic rupture of the aorta. Indications for aortography

The indications for thoracic aortography in the blunt chest trauma patient remain controversial. Clinical and radiographic findings in 102 patients seen at a Level I Trauma Center over a five-year period were reviewed to evaluate criteria predictive of major thoracic vascular injury. Five patients had positive aortograms. There was no significant correlation with Revised Trauma Score, symptoms, or associated thoracic injuries, although patients with aortic rupture did have a higher incidence of extrathoracic injuries (P less than 0.001). A blinded review of admitting chest radiographs for five major findings (widened mediastinum, aortic arch abnormalities, aortopulmonary window opacification, left apical capping, and right apical capping) revealed a significant difference between patients with and without aortic injury (0.98 +/- 1.24 findings in the negative aortogram group and 3.00 +/- 0.71 findings in the positive aortogram group) (P less than 0.001). All patients with aortic rupture had at least two major positive findings on admitting chest radiographs. Admission chest x-ray evidence of at least one major abnormality is a safe method of screening blunt chest trauma patients for thoracic aortography.     

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.     

The potential effects of radiographic criteria to exclude aortography in patients with blunt chest trauma. Results of a study of 32 patients with proved aortic or brachiocephalic arterial injury

The purpose of this study was to test the effectiveness, in patients with known aortic or brachiocephalic arterial injury, of five previously published radiographic criteria for excluding aortography in patients with blunt chest trauma. These criteria were (1) normal findings on erect chest radiograph; (2) normal aortic arch and left subclavian artery; (3) normal aortic arch, descending aorta, aortopulmonary window, tracheal position, and left paraspinal interface; (4) normal right paratracheal stripe and nasogastric tube position, and (5) normal aortic arch and tracheal and nasogastric tube position. One or more of these criteria were met in 6% to 25% of patient with major thoracic arterial injury, depending on the criteria used. Interestingly, two (6%) patients had radiographs that showed no specific signs of mediastinal hemorrhage, which indicates that the chest radiograph is limited in its sensitivity to detect major thoracic arterial injury. Because of these results, we do not believe that attempts to limit aortography in patients with supine film evidence of mediastinal abnormality, based on the absence of certain signs of mediastinal hemorrhage, are warranted. Furthermore, an abnormal radiograph cannot be relied on as the sole criterion for aortography if the goal of care is to detect as close to 100% of vascular injuries as possible.     

The role of CT angiography in the diagnosis of blunt traumatic thoracic aortic disruption and unsuspected carotid artery injury

We have replaced aortography and open thoracic surgery to diagnose and treat blunt traumatic thoracic aortic disruption (TTAD) in favor of CT angiography (CTA) and endovascular repair. The purpose of this study is to review our experience with the management and outcomes of TTAD and associated carotid artery injuries. In January 2003, we initiated a protocol that used CTA to evaluate all patients with suspected TTAD from blunt trauma. When TTAD was diagnosed, patients were managed by endovascular repair using abdominal aortic extension cuffs. Twenty-nine patients with TTAD were managed by endovascular repair. In all patients, abdominal endograft extension cuffs successfully excluded the traumatic disruptions. Six (21%) of these patients had concomitant, unsuspected carotid artery injury diagnosed by CTA. One patient had bilateral carotid artery dissections, sustained irreversible brain injury, and died. Four patients with common carotid dissections were successfully treated by anticoagulation and made uneventful recoveries. One patient with a common carotid-innominate artery dissection and pseudoaneurysm underwent endovascular repair. This study indicates that CTA and endovascular repair provide accurate diagnostic and therapeutic results in the management of blunt TTAD. Furthermore, CTA should include arch and cervical views to detect an unsuspected, concomitant carotid artery injury.     

Clinical and radiographic indications for aortography in blunt chest trauma

To determine which clinical and radiographic findings are valuable in selecting patients with blunt chest trauma for aortography, we analyzed the medical records and admission chest radiographs of 76 consecutive victims of blunt chest trauma with suspected thoracic aortic rupture during the past 7 years. All patients were evaluated by history, physical examination, chest radiography, and aortography; a total of 70 clinical and radiographic findings were independently assessed in each patient. The following occurred with significantly greater frequency in patients with thoracic aortic rupture than in those without: history of significant hypotension (mean arterial pressure less than 80 mm Hg) (p less than 0.04); the presence of upper extremity hypertension, bilateral lower extremity pulse pulse deficits, or an initial chest tube output greater than 750 ml of blood (p less than 0.05); and greater incidence of myocardial contusions, intra-abdominal injuries, and pelvic fractures compared with patients without thoracic aortic rupture (p less than 0.05). Mediastinal widening (equal to or greater than 8 cm) shown on anteroposterior chest radiography occurred in all patients with thoracic aortic rupture; however, its specificity was only 10.6%. Radiographic signs that were helpful in indicating the presence of thoracic aortic rupture included paratracheal stripe greater than 5 mm, rightward deviation of the nasogastric tube or central venous pressure line, blurring of the aortic knob, and an abnormal or absent paraspinous stripe. Upper rib fractures and mediastinal to thoracic cage width ratios at any level did not increase diagnostic accuracy for thoracic aortic rupture in the present series. Six patients in the series died, two of whom had thoracic aortic rupture.(ABSTRACT TRUNCATED AT 250 WORDS)     

Diagnosis of traumatic thoracic aortic rupture: a 10-year retrospective analysis

A 10-year retrospective analysis of 82 patients with suspected thoracic aortic rupture (TAR) due to blunt chest trauma was performed to define which symptoms and signs were helpful in making an early diagnosis. Symptoms and signs associated with TAR included midscapular back pain (in the absence of thoracic spine fracture), unexplained hypotension, upper extremity hypertension, bilateral femoral pulse deficits, and initial chest tube output in excess of 750 mL. Chest roentgenographic signs seen with significantly greater frequency in the 12 patients with TAR than in 70 patients without such rupture included a widened paratracheal stripe (7 patients), deviation of the nasogastric tube or central venous pressure line (5 patients), blurring of the aortic knob (9 patients), abnormal paraspinous stripe (6 patients), and rightward tracheal deviation (5 patients). Mediastinal widening of greater than 8 cm occurred in 11 of the 12 patients with TAR (sensitivity, 92%); its specificity, however, was only 10% (11 true-positive and 63 false-positive results). In patients in hemodynamically stable condition who display these findings, immediate aortography should be considered. The presence of myocardial contusions, intraabdominal injuries, and pelvic fractures also occurred more frequently in patients with TAR. We conclude that a detailed history, physical examination, and chest roentgenography, with rapid progression to aortography in suspicious cases, represent the safest and most reliable approach to patients with TAR.     

Use of CT for diagnosis of traumatic rupture of the thoracic aorta

CT imaging of traumatic aortic rupture has been both advocated and disparaged in the current literature as a reliable diagnostic modality. In a retrospective review of blunt chest trauma patients at our institution evaluated by both thoracic CT and arteriography, we found a 17% false negative rate and a 39% false positive rate. Although we feel CT is not sufficiently sensitive at present to evaluate traumatic rupture of the aorta directly, it is an invaluable adjunctive imaging modality for stable blunt chest trauma patients with equivocal chest radiographs or arteriograms.     

Management of blunt thoracic aortic injuries: endovascular stents versus open repair

BACKGROUND: Endovascular stent graft (EV) technology has been successfully adapted to the repair of blunt traumatic aortic injuries. The purpose of this study was to compare the outcomes of patients treated with EV repair and open repair after blunt thoracic aortic trauma. METHODS: A review of a tertiary trauma center's prospective trauma registry identified all patients who suffered a blunt traumatic thoracic aortic injury over an 11-year period (1991-2002). Operative interventions and outcomes were then compared. RESULTS: Over an 11-year period, 18 patients underwent repair of a blunt thoracic aortic injury (EV, 6; open, 12). There were no significant differences in demographics, injury, or crash statistics between groups. The open group had a 17% early mortality rate (n = 2), a paraplegia rate of 16% (n = 2), and an 8.3% incidence of recurrent laryngeal nerve injury (n = 1). This is in contrast to a 0% rate of mortality, paraplegia, and recurrent laryngeal nerve injury in the EV group. A definite trend toward decreased morbidity, mortality, intensive care unit length of stay, and number of ventilator-dependent days was seen with EV repair. CONCLUSION: We observed a clear trend toward improved outcomes after EV repair of thoracic aortic injuries compared with standard open repair. EV repair is emerging as the preferred method of repairing blunt thoracic aortic injuries in trauma patients with multiple injuries.     

TRAUMATIC THORACIC AORTIC RUPTURE: INVESTIGATION DETERMINES OUTCOME

Blunt thoracic aortic rupture (TAR) initially presents with subtle signs but is usually fatal if not diagnosed and treated early. Does the diagnostic process affect outcome? The definitive test most widely promoted is thoracic (arch) aortography but is usually only available in major teaching hospitals. Thoracic computerized tomography (CT) scanning is more readily available but its role in diagnosis of TAR is unproven. A retrospective review of trauma databases and medical record indexes over a 7 year period identified 38 patients presenting with TAR at Westmead and Royal North Shore Hospitals in the period 1984–91. Thirteen patients (34%) were dead on arrival or died within 15 min of arrival at either hospital. Five patients (13%) who arrived in cardiac arrest (with suspected TAR) died after immediate thoracotomy (two in the Emergency Department and three in the operating room). Two patients (5%) died from severe head injuries and were not investigated for TAR. Eighteen patients (47%) remained alive long enough for investigation and were considered potentially salvageable. Nine of these survived. Only 13 patients had arch aortography. No patient survived without an aortogram. Five patients had a chest CT scan; aortography followed in four patients. Computerized tomography scans delayed aortography or were misinterpreted. Review of all trauma thoracic (arch) aortograms for the same period at Westmead Hospital revealed a diagnosis of TAR in 7.4%. Blind thoracotomy did not result in survival. Computerized tomography scanning of the chest was of no value in the management of this injury. Early suspicion of possible thoracic aortic rupture demands urgent arch aortography and this remains the diagnostic ‘gold standard’.     

Blunt thoracic trauma. Analysis of 515 patients.

A retrospective analysis of 515 cases of blunt chest trauma is presented. The overall thoracic morbidity rate was 36% and mortality rate was 15.5%. Atelectasis was the most common complication. Severe chest trauma can be present in the absence of rib or other thoracic bony fractures. Emergency thoracotomies for resuscitation of the patient with blunt chest trauma with absent vital signs proved unsuccessful in 39 of 39 patients. A high index of suspicion for blunt chest injury occurring in blunt trauma, coupled with an aggressive diagnostic and therapeutic approach, remains the cornerstone of treatment to minimize the morbidity and mortality of such injuries.     

Traumatic disruption of the thoracic aorta in children.

HYPOTHESIS: This study was undertaken to identify mechanisms of injury, diagnostic modalities, surgical management, and outcome in children with traumatic aortic disruptions. DESIGN: Retrospective study. SETTING: University-affiliated private hospital. PATIENTS: All patients younger than 17 years listed in the trauma registry. INTERVENTION: Operative repair of thoracic aortic injuries. MAIN OUTCOME MEASURES: There were 8 boys and 3 girls ranging in age from 12 to 17 years (mean, 14.8 years). Seven children were motor vehicle passengers; 3 were pedestrians struck by vehicles; and 1 was thrown from a bull. Aortic injuries were suspected on the basis of the mechanism of injury and abnormal chest x-ray films (mediastinal widening). Aortic injuries were confirmed in 9 patients by arch aortography and in 2 patients by computed tomography. The injuries involved the isthmus of the aorta in 9 patients (complete transections) and the aortic arch in 2 patients (avulsions of the great vessels). Isthmus injuries were repaired by means of left heart bypass with direct cannulation of the distal thoracic aorta in 8 patients and femoral venous to femoral arterial bypass in 1 patient. Arch injuries were repaired during hypothermic circulatory arrest. The injured aortic segments were replaced with interposition grafts. There were no direct complications of anticoagulation. Ten patients (91%) survived. The only death was caused by a severe closed head injury. There were no instances of paraplegia related to aortic repairs. CONCLUSION: Good outcomes resulted from early diagnosis based on mechanism of injury, prompt aortography, and computed tomography and operative management that included distal aortic perfusion with left heart bypass.     

The clinical significance of occult thoracic injury in blunt trauma patients

Increased use of thoracic CT (TCT) in diagnosis of blunt traumatic injury has identified many injuries previously undetected on screening chest x-ray (CXR), termed "occult injury". The optimal management of occult rib fractures, pneumothoraces (PTX), hemothoraces (HTX), and pulmonary contusions is uncertain. Our objective was to determine the current management and clinical outcome of these occult blunt thoracic injuries. A retrospective review identified patients with blunt thoracic trauma who underwent both CXR and TCT over a 2-year period at a Level I urban trauma center. Patients with acute rib fractures, PTX, HTX, or pulmonary contusion on TCT were included. Patient groups analyzed included: (1) no injury (normal CXR, normal TCT, n=1337); (2) occult injury (normal CXR, abnormal TCT, n=205); and (3) overt injury (abnormal CXR, abnormal TCT, n=227). Patients with overt injury required significantly more mechanical ventilation and had greater mortality than either occult or no injury patients. Occult and no injury patients had similar ventilator needs and mortality, but occult injury patients remained hospitalized longer. No patient with isolated occult thoracic injury required intubation or tube thoracostomy. Occult injuries, diagnosed by TCT only, have minimal clinical consequences but attract increased hospital resources.     

CT as a first-line modality in elderly patients with stable blunt chest trauma

Purpose: Blunt thoracic injuries are common among elderly patients and may be a common cause of morbidity and death from blunt trauma injuries. We aimed to examine the impact of chest CT on the diagnosis and change of management plan in elderly patients with stable blunt chest trauma. We hypothesized that chest CT may play an important role in providing optimal management to this subgroup of trauma patients. Methods: A retrospective analysis was performed on all the admitted adult blunt trauma patients between January 2014 and December 2018. Stable blunt chest trauma patients with abbreviated injury severity (AIS) < 3 for extra-thoracic injuries confirmed with chest X-ray (CXR) and chest CT on admission or during hospitalization were included in the study. The AIS is an international scale for grading the severity of anatomic injury following blunt trauma. Primary outcome variables were occult injuries, change in management, need for surgical procedures, missed injuries, readmission rate, intensive care unit (ICU) and length of hospital stay. Results: There are 473 patients with blunt chest trauma included in the study. The study patients were divided into two groups according to the age range: group 1: 289 patients were included and aged 18-64 years; group 2: 184 patients were included and aged 65-99 years . Elderly patients in group 2 more often required ICU admission (11.4% vs. 5.2%), had a longer length of ICU stay (days) (median 11 vs. 6, p = 0.01), and the length of hospital stay (days) (median 14 vs. 6, p = 0.04). Injuries identified on chest CT has led to a change of management in 4.4% of young patients in group 1 and in 10.9% of elderly patients in group 2 with initially normal CXR. Chest CT resulted in a change of management in 12.8% of young patients in group 1 and in 25.7% of elderly patients in group 2 with initially abnormal CXR. Conclusion: Chest CT led to a change of management in a substantial proportion of elderly patients. Therefore, we recommend chest CT as a first-line imaging modality in patients aged over 65 years with isolated blunt chest trauma.     

The significance of chest wall injury in the diagnosis of traumatic aneurysms of the thoracic aorta

It has been suggested that patients sustaining blunt chest injury severe enough to result insignificant bony injury to the thorax may have traumatic aneurysms of the thoracic aorta in the absence of th widened mediastinum on plain film. To test the validity of this hypothesis, we performed aortograms on 14 patients with severe blunt chest injury but an otherwise normal chese X-ray. None of these patients was found to have an aortic injury. By contrast, of 21 patients with severe chest injury and a widened mediastinum who underwent thoracic aortography eight were found to have traumatic aneurysms of the thoracic aorta. These results suggest that in the absence of a widened mediastinum, severe chest wall injury is not an indication for aortography.     

Derivation of a clinical decision rule to exclude thoracic aortic imaging in patients with blunt chest trauma after motor vehicle collisions

BACKGROUND: Thoracic aortic injury (TAI) is associated with high mortality. It is not practical to evaluate all patients with blunt chest trauma with dedicated aortic imaging. The purpose of this study was to define a group of patients with blunt chest trauma after motor vehicle collision (MVC) that do not require aortic imaging based on information available in the emergency department. METHODS: This was a secondary analysis of a prospectively-collected database. Consecutive patients with blunt chest trauma after MVC were included. Characteristics of mechanism, examination, and chest radiographic findings were collected for each patient. All patients underwent chest computed tomography (CT), aortography, or both for TAI evaluation. Binary recursive partitioning was used to derive and validate a clinical decision rule to predict exclusion of TAI. RESULTS: During the study period, 1,096 patients were included, and 22 (2.0%) were diagnosed with TAI. The decision rule for exclusion of TAI included findings from the chest radiograph, incorporating left paraspinous line displacement, obscured aortic knob, and mediastinal widening. The rule resulted in a sensitivity of 86% (95% confidence interval [CI]: 65% to 97%), a specificity of 77% (95% CI: 75% to 80%), a positive predictive value of 7% (95% CI: 4% to 11%), a negative predictive value (NPV) of 99.6% (95% CI: 99.0% to 99.9%), a positive likelihood ratio of 3.8 (95% CI: 1.1-12.9), and a negative likelihood ratio of 0.18 (95% CI: 0.05-0.61). This would potentially reduce aortic imaging by 76% (95% CI: 74% to 79%). CONCLUSION: We report a clinical decision rule with a high NPV for exclusion of TAI. This may standardize the approach to such patients and may reduce the need for CT.