The epidemiology of thoracic aortic injuries in pedestrians

Fatal Motor Vehicle-Pedestrian Collision Injury Patterns-A Systematic Literature Review

INTRODUCTION

Injury patterns in pedestrians struck by motor vehicles were described in medical literature first published almost a half century ago. "Classical" triads of injury distribution were described for adults (skull-pelvis-extremity) and subsequently applied to children (head-hip or pelvis-distal femur/knee joint). Notably, these classical triads were derived from two publications reporting clinical observations of only 11 patients, all of whom were adults.

METHODS

A systematic literature review was conducted using Medline, CINAHL, EMBASE, and Cochrane to determine the evidence-base for motor vehicle collision (MVC)-pedestrian injury "triads" and other trauma patterns described for pedestrians in the adult and pediatric age groups.

RESULTS

Of the 1540 full-text articles identified in the review, 56 articles published in English met the inclusion criteria, that is, motor vehicle-pedestrian collision resulting in specific, fatal injuries determined by postmortem examinations. There were variations in injury patterns that differed from the "classical" triads. These differences likely stem from advances in vehicle design and safety features which have affected the nature and distribution of injuries.

DISCUSSION

Further research on the correlation of specific injuries sustained by pedestrians of different ages with various types of vehicles and impacts are needed to assess the validity of previously observed injury patterns in relation to the current motor vehicle fleet. Delineation of injury patterns can assist health care teams in trauma management. Vehicle manufacturers and government regulators can better assess whether the introduction of advanced driver assistance features designed to protect pedestrians when struck will be effective in reducing severe injuries. In forensic pathology practice, knowledge of pedestrian injury patterns based on data representative of impacts involving modern vehicles can provide MVC death investigators the means to determine MVC dynamics and pedestrian kinematics.

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.

The endovascular repair of blunt traumatic thoracic aortic injury in Asia: A systematic review and meta-analysis

INTRODUCTION

Blunt traumatic thoracic aortic injury, the second leading cause of death from trauma, poses unique challenges in its management. However, there has not yet been a corresponding consolidated series of outcomes reported in Asia, which this systematic review aims to address.

METHOD

This review was performed as per the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Searches were performed on MEDLINE, EMBASE, Google Scholar, and Cochrane Database for studies performed in Asia reporting the endovascular management of blunt traumatic thoracic aortic injury. Risk of bias was assessed using the Newcastle-Ottawa scale. Meta-analyses of pooled proportions were performed using the metaprop command in STATA. This review has been prospectively registered in PROSPERO (CRD42018083773).

RESULTS

Sixteen retrospective cohort studies were included, reporting a total of 238 patients. The pooled Injury Severity Score was 32.5 (95%CI 27.8-37.1). The pooled mean time to operation from diagnosis was 39.2 hours (95%CI 24.6-53.8 hours), and operation time was 100 min (95%CI 63.5-136.5 min). The pooled rate of procedural conversion from endovascular repair to open surgery was 0.17% (95%CI 0-3.7%), and the proportion of left subclavian artery coverage was 55% (95%CI 37-72%). The pooled prevalence of intra-operative all-cause and aortic-related mortality was 0.72% (95%CI 0-4.9%) and 0.27% (95%CI 0-3.8%), respectively. The pooled prevalence of 30-day all-cause and aortic-related mortality was 2.2% (95%CI 0.16-5.6%) and 2.1% (95%CI 0-3.7%), respectively. In terms of 30-day complication, the pooled prevalence rates of type 1 endoleak, endograft complications, vascular access injury, strokes, and aortic re-rupture were 1.2%, 0.34%, 0.14%, 0.02%, and 0.01%, respectively. There were no cases of types II and III endoleak, and renal failure.

CONCLUSION

Short- to mid-term results for thoracic endovascular aortic repair for blunt traumatic thoracic aortic injury in Asia are encouraging. However, there is a distinct disparity in reporting across Asia. We propose a prospective database for outcome reporting post thoracic endovascular aortic repair in this patient population, and ongoing follow up to assess long-term efficacy of this treatment strategy.

Recycling and Reinforcing Intimomedial Flap of the Infrarenal Aorta Using Anterior Longitudinal Ligament in Patients With Acute Trauma With Bowel Injuries

We present a patient with blunt abdominal trauma with severe acute right limb ischemia and clinical signs of diffuse peritonitis. Computed tomography angiography showed circumferential dissection of the infrarenal aorta with occlusion of the right common iliac artery. We opted for simultaneous abdomen exploration and open repair of injured aorta. Critical weakening of the aortic wall with imminent rupture was identified intraoperatively. Aortotomy cranially from bifurcation showed circumferential intimomedial dissection. The fixation of fragile intimomedial flap of aortic dissection was achieved with reinforcement using an anterior longitudinal ligament. The long aortoiliac arteriotomy was repaired using a great saphenous vein patch. Patient had uneventful postoperative course and was discharged after 7 days. In patients with abdominal polytrauma with peritonitis, and no available endovascular tools, open surgery for circumferential aortic dissection is possible and successful. Described reinforcement of the posterior aortic wall to the anterior longitudinal ligament should be added to the armamentarium of aortic injury treatment.

Five-year experience with the peri-operative goal directed management for surgical repair of traumatic aortic injury in the eastern province, Saudi Arabia

Context:

Traumatic aortic injury (TAI) accounts for 1/3 of all trauma victims.

Aim:

We aimed to investigate the efficacy of the adopted standardized immediate pre-operative and intra-operative hemodynamic goal directed control, anesthetic technique and organs protection on the morbidity and mortality in patients presented with TAI.

Settings and Design:

An observational retrospective study at a single university teaching hospital.

Materials and Methods:

Following ethical approval, we recruited the data of 44 patients admitted to the King Fahd Hospital of the University, Al Khobar, Saudi Arabia, with formal confirmation of diagnosis of blunt TAI during a 5-year period from February 2008 to April 2013 from the hospital medical records.

Statistical Analysis:

descriptive analysis.

Results:

A total of 44 victims (41 men, median (range) age 29 (22-34) years) with TAI who underwent surgical repair were recruited. Median (range) post-operative chest tube output was 700 (200-1100) ml necessitated transfusion in 5 (11.4%) of cases. Post-operative complications included transient renal failure (13.6%), pneumonia (6.8%), acute lung injury/distress syndrome (20.5%), sepsis (4.5%), wound infection (47.7%) and air leak (6.8%). No patient developed end stage renal failure or spinal cord injury. Median intensive care unit stay was 6 (4-30) days and in-hospital mortality was 9.1%.

Conclusion:

We found that the implementation of a standardized early goal directed hemodynamic control for the peri-operative management of patients with TAI reduces the post-operative morbidity and mortality after surgical repair.

[Management of traumatic aortic rupture. About 37 cases]

OBJECTIVES

The aim of this study was to review our experience in the management of traumatic rupture of the aortic isthmus, to evaluate the results of surgery and endovascular exclusion and to develop an adequate therapeutic strategy based on the existence and severity of associated injuries.

MATERIAL

A series of 37 patients presenting posttraumatic aortic rupture associated with other severe lesions was collected from 2000 to 2012. There were 33 males and four females, mean age 38 years. In this series, 25 patients underwent surgical treatment and 12 endovascular exclusion.

RESULTS

Six patients died during or after surgery. Overall mortality was 16% (24% in the surgery group). The postoperative period was uneventful in all patients treated with the endovascular procedure. Postoperative computed tomography controls at one week, 1 month and 12 months showed good positioning of the stent without endoleakage.

CONCLUSION

Traumatic aortic rupture is often the result of a severe high-energy chest trauma. Other serious injuries are often associated. Results of immediate surgical repair are associated with high morbidity and mortality. The advent of endovascular treatment has revolutionized the treatment of traumatic aortic rupture, especially in patients with a high surgical risk.

Potential long-term complications of endovascular stent grafting for blunt thoracic aortic injury

Blunt thoracic aortic injury (BTAI) is a rare, but lethal, consequence of rapid deceleration events. Most victims of BTAI die at the scene of the accident. Of those who arrive to the hospital alive, expedient aortic intervention significantly improves survival. Thoracic endovascular aortic repair (TEVAR) has been accepted as the standard of care for BTAI at many centers, primarily due to the convincing evidence of lower mortality and morbidity in comparison to open surgery. However, less attention has been given to potential long-term complications of TEVAR for BTAI. This paper focuses on these complications, which include progressive aortic expansion with aging, inadequate stent graft characteristics, device durability concerns, long-term radiation exposure concerns from follow-up computed tomography scans, and the potential for (Victims of Modern Imaging Technology) VOMIT.

Surgical repair for rupture of a chronic traumatic thoracic aneurysm 14 years after injury: report of a case

Traumatic thoracic aortic injury is a lethal condition. Because its mortality rate is extremely high in the acute phase, these patients rarely survive long enough for a chronic aneurysm to develop. We herein report a case of surgical repair for a ruptured chronic traumatic thoracic aneurysm. A 32-year-old man, who had been involved in a traffic accident 14 years earlier, was diagnosed with a rupture of a chronic traumatic thoracic aneurysm. Preoperative computed tomography showed that the ruptured aneurysm arose from the aortic isthmus and was accompanied by multiple daughter lesions. He underwent an aorta graft replacement with reconstruction of the left subclavian artery using both a median sternotomy and a left thoracotomy. The surgery was successful and the postoperative course was uneventful. Chronic traumatic thoracic aneurysm is usually a single lesion, and cases with daughter aneurysms have rarely been reported. We include a review of the previous literature and also discuss the etiology of this condition.

Blunt thoracic aortic injuries: an autopsy study

OBJECTIVE

The objective of this study was to identify the incidence and patterns of thoracic aortic injuries in a series of blunt traumatic deaths and describe their associated injuries.

METHODS

All autopsies performed by the Los Angeles County Department of Coroner for blunt traumatic deaths in 2005 were retrospectively reviewed. Patients who had a traumatic thoracic aortic (TTA) injury were compared with the victims who did not have this injury for differences in baseline characteristics and patterns of associated injuries.

RESULTS

During the study period, 304 (35%) of 881 fatal victims of blunt trauma received by the Los Angeles County Department of Coroner underwent a full autopsy and were included in the analysis. The patients were on average aged 43 years±21 years, 71% were men, and 39% had a positive blood alcohol screen. Motor vehicle collision was the most common mechanism of injury (50%), followed by pedestrian struck by auto (37%). A TTA injury was identified in 102 (34%) of the victims. The most common site of TTA injury was the isthmus and descending thoracic aorta, occurring in 67 fatalities (66% of the patients with TTA injuries). Patients with TTA injuries were significantly more likely to have other associated injuries: cardiac injury (44% vs. 25%, p=0.001), hemothorax (86% vs. 56%, p<0.001), rib fractures (86% vs. 72%, p=0.006), and intra-abdominal injury (74% vs. 49%, p<0.001) compared with patients without TTA injury. Patients with a TTA injury were significantly more likely to die at the scene (80% vs. 63%, p=0.002).

CONCLUSION

Thoracic aortic injuries occurred in fully one third of blunt traumatic fatalities, with the majority of deaths occurring at the scene. The risk for associated thoracic and intra-abdominal injuries is significantly increased in patients with thoracic aortic injuries.

Chest impact experiments aimed at producing aortic rupture

There are a number of proposed mechanisms of traumatic aortic rupture. These experiments involved three different chest impacts that may be associated with aortic rupture. Eleven unembalmed cadavers were repressurized and impacted by a 24-34 kg mass at 8.6-14.9 m/sec. Three impact orientations were studied with the torso axis: (1) 30-45° up from horizontal and impact 28-45° clockwise of the midsagittal axis, (2) 105-130° up from horizontal and impact 15° counterclockwise, and (3) 75° up from horizontal and impact 15° counterclockwise. Spinal acceleration was measured at T1, T8, and T12 and chest compression was determined by high-speed video. Detailed autopsy determined injuries. Impact loads averaged 9.65 ± 2.45 kN and resulted in 52.8 ± 5.4% chest compression and 3.53 ± 0.94 m/sec Viscous response. The resultant spinal acceleration was 124.5 ± 105.4 g at T1, 141.3 ± 80.5 g at T8 and 89.3 ± 39.1 g at T12. The severity of impact resulted in multiple rib fractures and severe chest injury averaging AIS = 4.2 ± 1.0. There were four cases of heart laceration and one transection of the ascending aorta 20 mm from the cusp of the aortic valve. The impacts were severe enough that aortic rupture was expected; however, only one occurred. In retrospect, the position of the heart and aorta in the upright cadaver may not have been representative of the position during human injury, thus reducing the incidence of aortic rupture in these experiments.

Delayed rupture of thoracic aorta aneurysm following a kick to the abdomen

Several theories have been proposed to explain the Blunt Traumatic Aortic Rupture (BTAR) because different mechanical forces act on the aorta, at anatomically susceptible sites, including shearing, torsion and stretching, but the origin, transduction and relative importance of these forces remain uncertain. We report a case of a 74-year-old man injured by a kick to the abdomen. After 2 days he felt chest pain paroxysm and weakness in his left leg. The patient was admitted to an emergency care department where he experienced sudden and severe hemodynamic deterioration, dying rapidly. The autopsy, performed 3 days later, showed haemorragic infarction of hypogastric subcutaneous tissues and revealed an extended dissecting aneurysm of the thoracic aorta with following haemopericardium. In our case we considered that a low energy compression to the abdomen, in presence of underlying atherosclerosis, caused aortic dissection rather than rupture and then the 48h time span after the traumatic event and the cardiac tamponade was enough to complete the aortic retrograde dissection. We finally emphasise the importance of the careful surveillance of any trauma close to the abdomen in view of initially unpredictable, as well as eventful injuries. The finding of early signs of neointima formation in thoracoabdominal portions of aortic dissection strongly supported our interpretation. The forensic interest of this case is correlated to the voluntary character of the inflicted injury. The culprit was thus charged with manslaughter.

Overview of Great Vessel Trauma

Traumatic injury to the aorta and the brachiocephalic branches are potentially lethal injuries. Specialized preoperative imaging and medical management can lead to better outcomes in this group of patients. In addition, improved surgical techniques for spinal cord protection have led to decreased morbidity in surgical candidates. TEVAR remains a promising technique; however, long-term data currently are not available.

An Experimental Cadaveric Study for a Better Understanding of Blunt Traumatic Aortic Rupture

BACKGROUND

Blunt traumatic aortic rupture (BTAR) is a common catastrophic injury leading to death. Considerable uncertainty remains regarding the pathogenic cause. This study examines the comportment of the heart and the aorta during a frontal deceleration.

METHODS

Accelerometers were placed in the right ventricle of the heart, the aorta, the sternum, and the spine of six trunks removed from human cadavers. Different vertical decelerations were applied to cadavers and the relative motion of these organs was studied (19 tests).

RESULTS

The deceleration recorded in the isthmus of the aorta was always higher that the one recorded in the heart (p < 0.05). The difference of deceleration was 17% and increased with the speed's fall (extremes 5-25%). There was no significant difference of deceleration between the bony structures of the thorax. These results experimentally demonstrate for the first time that the fundamental mechanism of BTAR is sudden stretching of the isthmus of the aorta.

CONCLUSION

Four mechanisms are suspected to explain the location of the rupture: two hemodynamic mechanism (sudden increase of intravascular pressure and the water-hammer effect), and two physical mechanisms (sudden stretching of the isthmus and the osseous pinch). A greater understanding of the mechanism of this injury could improve vehicle safety leading to a reduction in its incidence and severity. Future work in this area should include the creation of an inclusive, dynamic model of computer-based modeling systems. This study provides for the first time physical demonstration and quantification of the stretching of the isthmus, leading to a computerized model of BTAR.

A case of aortic dissection caused by blunt chest trauma

A 74-year-old woman was struck by a car travelling at about 50 km/h. On arrival at hospital, a CT scan showed dissection of the ascending and descending aorta. She collapsed and died suddenly 8h later. At autopsy, there was massive bleeding into the left pleural cavity, ruptures of the pericardium and right ventricle, and a type A thoracic aortic dissection. The cause of death was haemorrhagic shock due to rupture of the pericardium and delayed rupture of the right ventricle following trauma to the chest. The thoracic aortic dissection was not the direct cause of death although histological examination did reveal that it occurred in the accident. Traumatic aortic dissection is rare although traumatic aortic rupture is a major cause of death after blunt chest trauma. This paper discusses the mechanisms, and factors involved in aortic dissection caused by blunt trauma.