Blunt Traumatic Aortic Rupture Research Articles

Numerical simulation of flows in a circular pipe transversely subjected to a localized impulsive body force with applications to blunt traumatic aortic rupture

Much debate surrounds the mechanisms responsible for the occurrence of blunt traumatic aortic rupture in car accidents, particularly on the role of the inertial body force experienced by the blood due to the abrupt deceleration. The isolated influence of such body forces acting on even simple fluid flows is a fundamental problem in fluid dynamics that has not been thoroughly investigated. This study numerically investigates the fundamental physical problem, where the pulsatile flow in a straight circular pipe is subjected to a transverse body force on a localized volume of fluid. The body force is applied as a brief rectangular impulse in three distinct cases, namely during the accelerating, peak, and decelerating phases of the pulsatile flow. A dimensionless number, termed the degree of influence of the body force (Ψ), is devised to quantify the relative strength of the body force over the flow inertia. The impact induces counter-rotating cross-stream vortices at the boundaries of the forced section accompanied by complex secondary flow structures. This secondary flow is found to develop slowest for an impact occurring during an accelerating flow and fastest during a decelerating flow. The peak skewness of the velocity field, however, occurred at successively later times for the three respective cases. After the impact, these secondary flows act to restore the unforced state and such dominant spatial structures are revealed by proper orthogonal decomposition of the velocity field. This work presents a new class of problems that requires further theoretical and experimental investigation.

Mortality from Blunt Traumatic Aortic Rupture

To determine risk factors for death in patients with traumatic aortic rupture, researchers reviewed trauma center and autopsy records for 85 patients

Blunt traumatic aortic rupture of the proximal ascending aorta repaired by resection and direct anastomosis

Traumatic aortic injury represents 15% of motor vehicle related deaths with death occurring at the scene in 85% of the cases. Aortic disruptions usually occur at the isthmus in a transverse fashion with all three of the aortic layers being involved. Herein, we report the case of a 68-year old man with no prior medical history who was struck by a vehicle while riding his bicycle. The ruptured segment of aorta was resected circumferentially and interrupted horizontal mattress pledgeted prolene sutures were used to ensure full thickness aortic integrity of the proximal and distal aortic segments. The aorta was closed with a single-layer technique using 4/0 prolene suture. There were no postoperative complications and patient was discharged on Day 44. The case here discussed demonstrates a rare presentation of blunt aortic injury. The proximal ascending aorta is an unusual site of transection following blunt trauma with few reports in the literature. We were able to repair the aorta with direct suture, thus avoiding the use of artificial material.

Low-impact scenarios may account for two-thirds of blunt traumatic aortic rupture

BackgroundTraditionally, blunt traumatic aortic rupture (BTAR) is thought to be a high-velocity injury. It was hypothesised that BTAR has a higher than suspected incidence in low-speed accidents, with unique kinematic...

Three strikes – don't die of a broken heart

There are multiple layers of complexity in prevention of vehicle related blunt traumatic aortic rupture (BTAR), many of which are enshrined within government policy and car design. We present a 'layers of protection analysis' (LOPA) based loosely on original work by Professor John Doyle, which describes these attempts to 'design out' the risk of BTAR following a vehicle collision. We have modified this approach to include a physiological dimension suggesting that this may be a factor in susceptibility to aortic injury following trauma. Understanding processes involved in BTAR following vehicle collisions is key to designing preventative processes.

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 48 h 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.

Regional wall mechanics and blunt traumatic aortic rupture at the isthmus

Blunt traumatic aortic injury (BTAI) is part of a spectrum of diseases termed acute aortic syndrome that accounts for 20% of road traffic accident related deaths. The injury has a complex aetiology with a number of putative mechanisms accounting for the injury profile, characteristics of which include a transverse primary intimal tear located at the aortic isthmus. We hypothesised that an understanding of regional aortic wall mechanics would contribute to an understanding of the aetiology of BTAI. Samples of porcine aorta were prepared from ascending (A), descending (D) and peri-isthmus regions (I). A histological analysis of aortic wall architecture was performed at the site of attachment of the ligamentum arteriosum. Samples were mounted in a bubble inflation clamping rig, connected via a solenoid release valve to a compressed air reservoir. Using a pressure transducer and high-speed camera (1000fps) we collected data on wall thickness, rupture pressure and radial extension, allowing calculation of ultimate tensile stress. Histological analysis at the point of attachment of the ligamentum arteriosum to the isthmus shows some heterogeneity in cellular architecture extending deep into the tunica media. Wall thickness was significantly different between the three sampled regions (A>I>D, p<0.05). However, we found no difference in absolute rupture pressure between the three regions (kPa), (A, 300+/-28.9; I, 287+/-48.3; D, 321+/-29.6). Radial extension (cm) was significantly greater in A vs I (p<0.05), (A, 1.85+/-0.114; I, 1.66+/-0.109; D, 1.70+/-0.138). Ultimate tensile stress (kPa), (A, 3699+/-789; I, 3248+/-1430; D, 4260+/-1626) was significantly greater in D than I (p<0.05). The mechanism of blunt traumatic aortic rupture is not mechanically simple but must correspond to a complex combination of both relative motion of the structures within the thorax and local loading of the tissues, either as a result of their anatomy or due to the nature of the impact. A pressure spike alone is unlikely to be the primary cause of the peri-isthmus injury but may well be a contributory prerequisite.

Blunt traumatic abdominal aortic rupture: CT imaging

Blunt abdominal aortic trauma is a rare but potentially lethal event. It is commonly associated with high-speed motor vehicle accidents. Intimal flap, thrombosis, and pseudoaneurysm of the abdominal aorta are the more common findings. We present a case of blunt abdominal aortic trauma in which CT disclosed free aortic rupture with intraabdominal bleeding and a huge retroperitoneal hematoma, an extremely rare finding among patients reaching the hospital alive, due to its high and immediate mortality rate.

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

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. 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). 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. 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.

Anticipatory Valsalva-type response as a contributory factor in low impact blunt traumatic aortic rupture

Despite a range of trauma scenarios, fatal blunt injury to the chest commonly results from rupture of the aorta at the isthmus. The aetiology whereby blunt traumatic aortic rupture predictably occurs at the isthmus remains uncertain, and although a number of theoretical mechanisms have been proposed, no direct evidence exists supporting any one process. In addition, it is uncertain why some individuals who are exposed to relatively minor blunt trauma, sustain this injury. We have previously developed a finite element model in an attempt to simulate the large number of interdependent variables in this complex cardiopulmonary dynamic. This has led us to the conclusion that the physiological state at the moment of impact is important and that there may be a point of susceptibility to low impact blunt traumatic rupture in the cardiopulmonary dynamic. This manuscript suggests and develops an hypothesis based on the putative contribution of an anticipatory Valsalva-type response at the moment of impact and discusses possible mechanisms on how this might contribute to low impact blunt traumatic aortic rupture in individuals who sustain relatively minor trauma.

Prise en charge thérapeutique des ruptures traumatiques aiguës de l'isthme aortique. Revue bibliographique

Blunt traumatic aortic rupture is a life-threatening emergency usually related to a violent crash involving sudden deceleration. Treatment remains controversial in surviving patients who reach the hospital. The traditional management has been repair of the injury as soon as possible. Although techniques in aortic surgery have improved over the years, morbidity and mortality rates still remain high and are often the result of another associated injury. Delayed repair of the acute aortic tear has been increasingly reported in selected cases, allowing the patient to recover from other major injuries. More recently, with the introduction of the endoluminal aortic stent grafting, a new strategy was introduced for treatment of acute traumatic aortic rupture.

Surgical versus endovascular treatment of traumatic thoracic aortic rupture

Blunt traumatic thoracic aortic rupture is a life-threatening surgical emergency associated with high mortality and morbidity. The recent development of endovascular stent-graft prostheses offers a potentially less invasive alternative to open chest surgery, especially in patients with associated injuries. We sought to compare the results of conventional surgical repair and endovascular treatment of traumatic aortic rupture in a single center. From July 1998 to January 2004, 20 patients with acute blunt traumatic aortic rupture underwent treatment at our institution. All patients had a lesion limited to the isthmus, and associated injuries. Initial management included fluid resuscitation, treatment of other severe associated lesions, and strict monitoring of blood pressure. Eleven patients (9 men, 2 women; mean age, 32 years) underwent surgical repair, including direct suturing in 6 patients and graft interposition in 5 patients. Ten patients were operated on with cardiopulmonary support (left bypass with centrifugal pump, n = 2; extracorporeal circulation, n = 8). The delay between trauma and surgery was 2.6 days (range, 0-21 days). Nine patients (8 men, 1 woman; mean age, 32 years) underwent endovascular treatment with commercially available devices (Excluder, n = 2; Talent, n = 7). In all patients 1 stent graft was deployed. In 2 patients the left subclavian artery was intentionally covered with the device. The delay between trauma and endovascular treatment was 17.8 days (range, 1-68 days). One patient in the surgical group (9.1%) died during the intervention. Three surgical complications occurred in 3 patients (27%), including left phrenic nerve palsy (n = 1), left-sided recurrent nerve palsy (n = 1), and hemopericardium 16 days after surgery that required a repeat intervention (n = 1). No patient in this group had paraplegia. In the endovascular group successful stent-graft deployment was achieved in all patients, with no conversion to open repair. No patient died, and no procedure-related complications, including paraplegia, occurred in this group. Control computed tomography scans obtained within 7 days after endovascular treatment showed exclusion of pseudoaneurysm in all cases. Length of follow-up for endovascular treatment ranged from 3 to 41 months (mean, 15.1 months). Computed tomography scans obtained 3 months after endovascular treatment showed complete disappearance of pseudoaneurysm in all patients. In the treatment of blunt traumatic thoracic aortic rupture, the immediate outcome in patients who receive endovascular stent grafts appears to be at least as good as observed after conventional surgical repair. Long-term follow-up is necessary to assess long-term effectiveness of such management.

A finite element model of blunt traumatic aortic rupture.

Blunt traumatic aortic rupture has a scene survival of 2-5% and is present in 20% of all automobile fatalities. The manner in which the forces from a range of thoracic impacts are transduced through the thoracic cavity to produce consistent injury to the aortic isthmus remains uncertain. Our objective was to create and evaluate a computer based finite element (FE) model of the aorta and observe its behavior during blunt traumatic impacts. A finite element model of the thorax including details of the heart, aorta and pertinent thoracic structures was created and run under the FE code LS-DYNA3D. The motion response of the heart following a simulated thoracic impact was extracted from the thorax model and applied in a second more detailed model of the heart and aorta in order to investigate the stresses acting through the aortic isthmus during simulated thoracic impacts. Simulated impact studies show that the predicted peak chest compression of the thorax model matched the measured responses from non-embalmed human cadaver impact studies by Kroell et al., 1974. The more detailed heart-aorta model predicted maximum stresses at the isthmus and pulmonary artery bifurcation the sites of most common trauma injury. Analysis of the response of the finite element heart-aorta model during blunt thoracic trauma demonstrates its potential for predicting major vessel injury. The model will be helpful in the design of impact protection systems.

Rupture of the aorta following road traffic accidents in the United Kingdom 1992-1999. The results of the co-operative crash injury study.

The true incidence and survivability of blunt traumatic aortic rupture following road traffic accidents in the UK is unclear. The objective of this study was to determine the extent of blunt traumatic aortic rupture in the UK after road traffic accidents and the conditions under which it occurs. Data for the study was obtained from the Co-operative Crash Injury Study database. Road traffic accidents that happened between 1992 and 1999 and included in the Co-operative Crash Injury Study database were retrospectively investigated. A total of 8285 vehicles carrying 14,435 occupants were involved in 7067 accidents. There were 132 cases of blunt traumatic aortic rupture, of which the scene survival was 9% and the overall mortality was 98%. Twenty-one percent of all fatalities had blunt traumatic aortic rupture (130/613). Twenty-nine percent were due to frontal impacts and 44% were due to side impacts. Twelve percent of the blunt traumatic aortic rupture cases in frontal vehicle impacts were wearing seat belts and had airbag protection and 19% had no restraint mechanism. The Equivalent Test Speed of the accident vehicles, (where equivalent test speed provides an estimate of the vehicle impact severity and not an estimate of the vehicle speed at the time of the accident), ranged from 30 to 110 km/h in frontal impacts and from 15 to 82 km/h in side impacts. Blunt traumatic aortic rupture carries a high mortality and occurred in 21% of car occupant deaths in this sample of road traffic accidents. Impact scenarios varied but were most common from the side. The use of an airbag or seat belt does not eliminate risk. The injury can occur at low severity impacts particularly in side impact.

The mechanism of injury in blunt traumatic rupture of the aorta.

Rupture of the aorta accounts for a significant proportion of fatalities following blunt trauma. A great deal of consensus exists describing the circumstances under which acute traumatic aortic dissection occurs as well as its investigation and management. However, there remains some controversy surrounding the pathogenic aetiology underlying this injury. Univariate and multivariate models of blunt traumatic aortic rupture (BTAR) are discussed. To account for the consistency in the nature of BTAR, despite a range of trauma scenarios, the concepts of dynamic multivariate models and a final common pathway are introduced. Clinical management is described elsewhere. Greater understanding of the mechanism of BTAR could lead to a range of safety systems aimed at a reduction in its incidence and severity.

Periaortic hematoma on helical CT of the chest: a criterion for predicting blunt traumatic aortic rupture.

The purpose of this study was to evaluate the accuracy of helical CT of the chest for predicting blunt traumatic aortic ruptures when periaortic hematoma is used as a positive criterion. We recommend the use of periaortic hematoma as a criterion for predicting traumatic aortic ruptures on CT because this criterion is sensitive and can reduce the false-positive rate of CT interpretations.

Blunt traumatic aortic rupture: Detection with helical CT of the chest: Gavant L, Menke PG, Fabian T, et al. Radiology. 1995; 197:125–133

Blunt traumatic aortic rupture: Detection with helical CT of the chest: Gavant L, Menke PG, Fabian T, et al. Radiology. 1995; 197:125–133

Blunt traumatic aortic rupture: detection with helical CT of the chest.

To determine the effectiveness of helical computed tomography (CT) as a screening device to detect traumatic aortic rupture. Helical CT was used to examine 1,518 patients with nontrivial blunt trauma. Of these patients, 127 (8.37%) with abnormal CT scans of the mediastinum or aorta underwent thoracic aortography--89 patients solely for evaluation of mediastinal hematoma depicted at CT. Imaging abnormalities were correlated with surgical or clinical outcome. Twenty-one aortic injuries were identified that ranged from subtle intimal flaps to complete aortic disruption. Helical CT was more sensitive than aortography (100% versus 94.4%, respectively) but less specific (81.7% versus 96.3%, respectively) in detection of aortic injuries in patients who underwent both examinations. The association between CT findings and outcome was phi = 0.62 (chi2 = 49.1, 1 df, P < .01) and between aortography and outcome was phi = 0.85 (chi2 = 92.2, 1 df, P < .001). The P value of the difference between the phi coefficients was .10. Helical CT of the chest is effective for screening critically injured patients with possible blunt thoracic aortic injuries.

Acute blunt traumatic thoracic aortic rupture: Time intervals to treatment

Acute blunt traumatic thoracic aortic rupture: Time intervals to treatment