Management of blunt thoracic aortic injury

INTRODUCTION — Blunt thoracic aortic injury, which is a life-threatening injury, usually occurs at the aortic isthmus just distal to the left subclavian artery, but other sites can be affected.

The grade of aortic injury taken together with the patient's associated injuries and medical comorbidities determines the need for, timing, and type of thoracic aortic repair. Contemporary studies, which consist primarily of retrospective reviews, support conservative management of "minimal" blunt thoracic aortic injuries [1-6], delayed repair of contained thoracic aortic injury in the face of multiple other injuries [7-14], and a preference for thoracic aortic stent-grafting rather than open surgical repair, when anatomically feasible, particularly in high-risk patients [15-17].

The management of blunt thoracic aortic injury is reviewed. The clinical features and diagnosis of blunt aortic injury, and open surgical or endovascular techniques for repair, are discussed separately. (See "Clinical features and diagnosis of blunt thoracic aortic injury" and "Surgical and endovascular repair of blunt thoracic aortic injury".)

INITIAL MANAGEMENT — The initial resuscitation and management of blunt aortic injury includes placement of two large-bore peripheral intravenous catheters for fluid resuscitation and medications to lower the blood pressure to limit the extent of the injury.

Anti-impulse therapy — For patients whose systolic blood pressure is more than 100 mmHg, we suggest antihypertensive therapy with impulse control (negative inotropic therapy) to reduce the risk of extending the injury (intimal, medial, or adventitial) and rupture, and potentially reduce the volume of blood loss if ruptured.

Although there are no randomized trials, observational studies suggest a mortality benefit for antihypertensive therapy with impulse control (negative inotropic therapy) for the treatment of blunt aortic injury compared with historical controls [8,18,19]. Prior to the routine use of antihypertensive therapy for blunt aortic injury, mortality in the emergency department was approximately 12 percent in hemodynamically stable patients awaiting surgical repair [8,9,18,20,21]. In one prospective study, 71 patients awaiting repair were treated to manage their heart rate and blood pressure with a goal systolic blood pressure of approximately 100 mmHg and a pulse rate of <100 beats per minute [20]. In this study, no patient had an aortic rupture while waiting for repair.

The patient's heart rate and blood pressure should be controlled with a beta blocker, if not contraindicated. The goal heart rate is <100 beats per minute [20]. Intravenous esmolol, a rapidly acting beta blocker with a short half-life, is ideal for this purpose (table 1). Beta blockade should be in effect before additional medications are used. A calcium channel blocker such as diltiazem can be used if beta blockers are contraindicated. If beta blocker therapy alone has not achieved the goal of maintaining the systolic blood pressure at 100 mmHg, a vasodilator (eg, nitroprusside) can be added.

Patient transfer — Patients found to have blunt thoracic aortic injury should be treated at a trauma center that has operating room personnel (surgical, nursing, anesthesia personnel) experienced with pathologies affecting the thoracic aorta and appropriate facilities for perioperative care. Endovascular repair options and expertise should also be available. If this level of care is not available at the facility to which the patient presented, the patient should be transferred.

APPROACH TO MANAGEMENT — The approach to management depends upon the grade of aortic injury, as well as the hemodynamic status of the patient and presence of other injuries and medical comorbidities [22].

We use a relatively simple system for grading the severity of aortic injury, determined from imaging studies (computed tomography, transesophageal echocardiography) that may help to provide more consistency in reporting [18,23] (see "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Diagnosis' and "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Aortic injury grading'):

●Type I: Intimal tear or flap (image 1 and image 2)

●Type II: Intramural hematoma (image 3)

●Type III: Pseudoaneurysm (image 4 and image 2)

●Type IV: Rupture (eg, periaortic hematoma, free rupture) (image 5 and image 6)

Prior to the advent of high-quality computed tomography of the chest, blunt thoracic aortic injuries were uniformly taken to the operating room for open surgical repair when the injury was identified [7]. However, high-resolution scanning has identified a broader range of aortic injuries, some of which do not appear to require repair [24-27]. Transesophageal echocardiography (TEE) can also be used to help guide the management of these patients [26,28].

Hemodynamically unstable — Based upon Advanced Trauma Life Support (ATLS) principles, hemodynamically unstable trauma patients should be taken to the operating room for emergency exploration to determine the source of hemorrhage, which could be in the chest and/or abdomen. It is important to note that thoracic aortic injury is a contraindication to resuscitative endovascular balloon occlusion of the aorta (REBOA).

If the source of hemodynamic instability is blunt aortic injury, it should be immediately repaired. If aortic injury is identified, but life-threatening bleeding from another source is controlled (eg, spleen, liver, pelvic fracture), aortic repair can be delayed to allow resuscitation of the patient (damage control approach). (See 'Immediate versus delayed' below.)

Hemodynamically stable — Based upon retrospective reviews and our clinical experience, we use the following approach for hemodynamically stable patients with blunt thoracic aortic injury based upon injury grade and the patient's clinical status. Our approach is consistent with major trauma association guidelines [22]. Some patients appear to benefit from delayed repair.

●For type I injuries (intimal tear), we suggest nonoperative management, which consists of aggressive heart rate and blood pressure control, and serial imaging [18]. (See 'Anti-impulse therapy' above and 'Nonoperative management of minimal injuries' below.)

●For patients with type II, III, and IV injuries, we recommend repair. Without repair, the outcomes of untreated thoracic aortic rupture are poor. While awaiting repair, we aggressively control blood pressure and heart rate. Delayed repair may be appropriate for patients who are hemodynamically stable, particularly if the patient has severe coexistent injuries. (See 'Anti-impulse therapy' above and 'Immediate versus delayed' below.)

●High-risk patients with favorable anatomy may be best suited for endovascular repair if appropriate equipment and expertise are available. Patients with unfavorable anatomy may be better served with open repair. Anatomic features associated with higher risk of endograft failure include acuteness of the angle of the arch and short distances between the tear and arch vessels [29]. (See 'Open versus endovascular' below and "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Issues to consider'.)

NONOPERATIVE MANAGEMENT OF MINIMAL INJURIES — The duration and location of observational management of minimal injuries depends on the nature of other injuries and subsequent imaging showing progression or resolution of the injury. Due to often present serious concomitant injuries, many patients are observed in a monitored setting. (See 'Approach to management' above.)

Ongoing medical management — For patients who are candidates for nonoperative medical management, antihypertensive therapy initiated on admission is continued, and intravenous beta blockers are transitioned to oral medication, which is continued at least until follow-up imaging. (See 'Anti-impulse therapy' above.)

The duration of antihypertensive therapy for patients who will not undergo surgery has not been studied. Evidence of aortic wall healing on follow-up imaging may be sufficient to discontinue therapy.

Follow-up imaging — Because little is known of the natural history of conservatively managed blunt thoracic aortic injuries, we perform serial imaging following discharge for patients with blunt thoracic aortic injury who are managed nonoperatively [25]. However, there are no established protocols for follow-up imaging. Timing is left to the judgment of the practitioner based upon the anatomy of the lesion and relevant patient factors, such as age and renal function. We obtain the first follow-up chest computed tomography (CT) scan within the first three months after discharge. Loss to follow-up remains a significant problem in the management of trauma patients [30,31].

In one study, aortic injuries <20 mm in patients managed with beta blockers resolved at a mean of 10 days following the injury as identified on transesophageal echocardiography [32]. However, in another study, approximately 50 percent of injuries with a flap less than 10 mm with no or minimal periaortic hematoma developed a pseudoaneurysm by eight weeks after injury on serial CT scanning [1].

AORTIC REPAIR — Aortic repair for blunt aortic injury is indicated for patients with injury grades II, III, and IV. (See 'Approach to management' above.)

Immediate versus delayed — Immediate aortic repair may not be feasible for many injured patients, particularly those with serious coexistent injuries such as head, pulmonary, or cardiac injury, or other serious medical comorbidities. (See "Clinical features and diagnosis of blunt thoracic aortic injury", section on 'Associated injuries'.)

Delayed repair is an option for hemodynamically stable patients provided there are no signs of impending thoracic aortic rupture, significant aortic thrombus, massive pneumothorax, or luminal encroachment [10]. Guidelines from the Eastern Association for the Surgery of Trauma (EAST) recommend delayed repair for such patients [22]. While awaiting repair, heart rate and blood pressure should be aggressively controlled and serial imaging should be performed. Once associated major injuries are stabilized, the aortic injury can be repaired, generally with less anesthetic and surgical risk. (See 'Anti-impulse therapy' above.)

Postoperative outcomes appear to be improved for those who undergo delayed surgical repair compared with those who undergo immediate repair. Several observational studies have demonstrated the safety and perhaps even a preference for delayed repair in selected patients [4-14,33-38]; however, patients selected for delayed repair may have less severe injuries, possibly biasing the results. In a systematic review from EAST that included seven comparative studies (some exclusively open surgical repair, others open or endovascular repair), the pooled risks for death and paraplegia were significantly higher for early compared with delayed surgical repair (death: risk ratio [RR] 2.07, 95% CI 1.03-4.15; paraplegia: RR 5.90, 95% CI 1.51-22.9) [22].

●In one of the studies, which included a total of 481 patients (78 from an institutional review and 403 identified from the National Trauma Data Bank [NTDB]), mortality was significantly higher in each group among those who underwent early open surgical repair (20 versus 9 percent in the institutional review, and 22 versus 14 percent in the NTDB review) [35]. The chest abbreviated injury score was significantly higher for those who underwent early repair, whereas orthopedic injuries were more common for those who underwent delayed repair.

●In another review of 69 patients with blunt thoracic aortic injury, 21 patients underwent immediate repair and 45 patients underwent delayed repair. The mortality in the delayed repair group was lower (4.2 versus 19 percent) [10]. Both open and endovascular repair were performed in this study.

●In a comparison of AAST-1 and AAST-2 studies, as the mean time from injury to aortic repair increased from 16.5 to 54.6 hours, overall mortality related to blunt thoracic aortic injury decreased from 22 to 13 percent [7,14]. Some argue that the introduction of endovascular repair alone accounts for this difference. All the patients in the AAST-1 study underwent open repair while 65 percent of patients in the AAST-2 study underwent endovascular repair. Mortality related to thoracic endovascular repair in the AAST-2 study was 7.2 percent.

Open versus endovascular — Repair of blunt thoracic aortic injury can be performed using open or endovascular techniques.

●Open repair – Open thoracic repair involves primary repair of the aorta or replacement of the diseased aortic segment with a prosthetic tube graft through a thoracotomy incision. (See "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Open surgical repair'.)

●Endovascular thoracic aortic repair – Endovascular thoracic aortic repair involves the placement of modular graft components that are delivered via the iliac or femoral arteries to line the thoracic aorta and exclude the injury from the circulation. Endovascular thoracic aortic repair requires fulfillment of specific anatomic criteria. When stent-graft repair of blunt thoracic aortic injury is chosen, intravascular ultrasound (IVUS) and/or transesophageal echocardiography (TEE) may help guide endovascular stent sizing and placement [39-41] and enable identification of complications after device deployment [42]. (See "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Endovascular repair'.)

It is unlikely that randomized trials will ever be performed comparing open and endovascular repair for treatment of blunt aortic injury, but based upon observational studies that demonstrate improved perioperative outcomes [15,43-52], we agree with major trauma society and vascular society guidelines that suggest endovascular rather than open surgical repair for patients with indications for aortic repair and anatomy that is suitable for thoracic stent grafting [18,22]. This preference places a higher value on preventing perioperative mortality and morbidity, such as spinal cord ischemia, compared with endograft complications that lead to reintervention and uncertain long-term outcomes. Comparisons of the rates of major perioperative morbidity and mortality from retrospective reviews and pooled data suggest a benefit for endovascular repair [15,43,45-54]. In a review from the Eastern Association for the Surgery of Trauma (EAST) that included 37 nonrandomized studies, the risk of death was significantly reduced for endovascular compared with open surgical repair (RR 0.49, 95% CI 0.36-0.66), as was the risk for paraplegia (RR 0.34, 95% CI 0.17-0.69) [22]. Other institutional reviews have shown similar improved outcomes for endovascular repair [34,53-71]. At the author's institution, reductions in mortality rates for endovascular repair have also been seen, and also significantly shorter lengths of stay, less need for blood transfusion, and less need for postoperative tracheostomy [29,72].

It is important to keep in mind, though, that patients with blunt aortic injury may be more suited for one approach or another depending on local institutional resources and other issues such as the presence, location, and type of associated injuries; the location of the aortic injury and diameter of the aorta; the patient's life expectancy; and likelihood of cooperation with long-term follow-up in the event of endovascular repair. (See 'Patient transfer' above and "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Issues to consider'.)

Post-repair imaging and care — Following successful repair of blunt thoracic aortic injury, any antihypertensive medication that was initiated can be discontinued before discharge. We obtain a chest computed tomography (CT) scan prior to discharge, often within days of repair. Further imaging depends on the nature of the repair. (See "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Graft surveillance'.)

MORTALITY — Blunt thoracic aortic injury is a major cause of death from blunt trauma. In spite of representing less than 1 percent of injuries in patients involved in motor vehicle crashes, blunt aortic injury is responsible for 16 percent of the deaths [73]. It is estimated that 80 to 85 percent of patients die before arriving at the hospital [74,75]. Of the 15 to 20 percent of patients who survive long enough to be treated, 70 to 90 percent will survive their repair [7,74], for an overall survival of 10 to 18 percent. In a multicenter study involving 274 blunt aortic injuries, death in 63 percent of the patients was directly attributable to the aortic injury [51].

Although the presence of aortic injury contributes greatly to mortality, patients who do not survive have sustained significant associated injuries, and mortality correlates with injury severity score and degree of aortic wall disruption [76-78]. In a review of 71 patients with blunt thoracic aortic injury who underwent endovascular repair, the mean injury severity score was significantly higher (60 versus 42.6) for the 19 patients who died compared with the 52 who survived [23]. The use of nonoperative management for minimal injuries, delayed operative management for appropriate individuals, and endovascular rather than open surgical repair has contributed to a decreased mortality rate over time [37,59,79-81]. Differences in morbidity and mortality for open versus endovascular repair of blunt thoracic aortic injury are discussed in more detail elsewhere. (See "Surgical and endovascular repair of blunt thoracic aortic injury", section on 'Perioperative morbidity and mortality'.)

As would be expected, mortality rates are higher for patients with severe aortic injury who cannot be managed operatively. A systematic review that included 18 studies found a mortality rate of 46 percent for patients who were not repaired (all grades) compared with 9 and 19 percent in patients who were managed with endovascular or open repair, respectively [15]. There were no significant differences in the age of the patients or injury severity score between patients treated nonoperatively versus those treated with endovascular or open surgical repair.

By contrast, improved outcomes are reported for patients who are appropriately selected for nonoperative management. One study reported survival at a median of 1.8 years of 97 percent [2]. In another study, 11 of 13 patients who survived to discharge never required repair [8]. (See 'Immediate versus delayed' above.)

With thoracic endovascular aortic repair, perioperative (30-day) outcomes appear to be improved compared with traditional open surgery (9 versus 19 percent, in one meta-analysis [15]) [17,43,46,47,82]. However, the long-term effect of endovascular stenting in this predominantly younger population needs further assessment. Perioperative morbidity and mortality, and the decision to perform open surgical repair versus endovascular repair of the thoracic aorta, is discussed in detail elsewhere. (See 'Open versus endovascular' above and "Surgical and endovascular repair of blunt thoracic aortic injury".)

SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Thoracic trauma".)

SUMMARY AND RECOMMENDATIONS

●Initial care – The initial resuscitation and management of blunt aortic injury includes placement of two large-bore peripheral intravenous catheters for medication and fluid resuscitation. For patients whose systolic blood pressure is more than 100 mmHg, we suggest antihypertensive and anti-impulse therapy rather than no such therapy (Grade 2C). Goals of therapy are as follows (see 'Initial management' above):

•Maintain a goal heart rate <100 beats per minute.

•Maintain systolic blood pressure at approximately 100 mmHg.

●Aortic injury grading – Aortic injuries can be graded based upon computed tomography (CT) findings as follows (see 'Approach to management' above):

•Type I: Intimal tear or flap (image 1 and image 2)

•Type II: Intramural hematoma (image 3)

•Type III: Pseudoaneurysm (image 4 and image 2)

•Type IV: Rupture (eg, periaortic hematoma, free rupture) (image 5 and image 6)

●Hemodynamically unstable patients – Based upon Advanced Trauma Life Support (ATLS) principles, hemodynamically unstable trauma patients should be taken to the operating room for emergent exploration to determine the source of hemorrhage, which could be in the chest and/or abdomen. When blunt thoracic aortic injury is the source of hemodynamic instability, immediate repair should be undertaken. If aortic injury is present but not the source of life-threatening bleeding, patients may benefit from delayed aortic repair (damage control approach). (See 'Hemodynamically unstable' above.)

●Hemodynamically stable patients – We use the following approach for hemodynamically stable patents with blunt thoracic aortic injury based upon injury grade and the patient's clinical status (see 'Hemodynamically stable' above):

•For type I injuries (intimal tear), we suggest nonoperative management rather than any type of aortic repair (Grade 2C). Nonoperative treatment consists of aggressive management to maintain heart rate <100 beats per minute, blood pressure <100 mmHg, and serial imaging. (See 'Nonoperative management of minimal injuries' above.)

•For patients with type II, III, and IV injuries, we recommend repair (Grade 1B). The outcomes of untreated high-grade thoracic aortic rupture are overall poor. While awaiting repair, we aggressively control blood pressure and heart rate. Delayed repair may be appropriate for patients who are hemodynamically stable, particularly if the patient has severe coexistent injuries. (See 'Immediate versus delayed' above.)

●Aortic repair – For patients in whom repair is indicated for blunt thoracic aortic injury, and who have anatomy that is suitable for thoracic stent-graft placement, we suggest endovascular rather than open surgical repair (Grade 2C). Transfer may be appropriate if institutional resources and expertise are not available. The preference for endovascular repair places a higher value on preventing perioperative mortality and morbidity, such as spinal cord ischemia, compared with endograft complications that lead to reintervention and uncertain long-term outcomes. Reintervention following endovascular repair is needed in up to 20 percent of patients, and thus, patients who undergo endovascular repair require lifetime imaging surveillance, which exposes the patient to the ongoing risks of repeated radiation. (See 'Patient transfer' above and 'Aortic repair' above.)

●Nonoperative management of minimal injuries – The natural history of nonoperatively managed minimal blunt aortic injury is not well known, and there are no established protocols for follow-up imaging. We obtain serial imaging using chest CT in all patients who are being managed nonoperatively with the first scan obtained within the first three months following discharge. (See 'Ongoing medical management' above and 'Follow-up imaging' above.)