Delayed Treatment of Contained Blunt Traumatic Aortic Rupture

Abstract

A 45-year-old man sustained an intracerebral frontal hematoma and a contained aortic isthmic rupture in a head-on automobile collision. Due to the intracerebral hemorrhage, open repair was contraindicated. Treatment with a stent graft was selected but delayed until the next morning, because the correct stent size was unavailable. Two hours before the time scheduled for surgery, the patient experienced oxygenation problems and became hypotensive. Chest radiography revealed a new, severe left hemothorax. Fortunately, the stent graft had just arrived from the manufacturer, and it was deployed to seal the ruptured aorta. Immediate angiography showed good stent-graft position without any endoleak, as did a computed tomographic scan 2 days after the procedure. The patient was transferred to a rehabilitation unit to recover from his neurologic trauma. A 3-month follow-up computed tomographic scan showed the patient's condition to be unchanged. (Tex Heart Inst J 2003;30:229–32)

Blunt thoracic aortic rupture (BTAR) is a life-threatening injury responsible for 15% to 23% of deaths after motor vehicle accidents. ¹ Most victims die at the scene as a result of exsanguination; however, 15% to 20% of victims reach the hospital due to containment of a rupture by the aortic adventitia and the surrounding mediastinal structures. ² Up to 80% of patients who experience BTAR sustain concomitant injuries, such as pulmonary contusion, neurologic trauma, and intra-abdominal or pelvic hemorrhage. ³ Current accepted management of patients with BTAR comprises prompt diagnosis, evaluation, and treatment of other life-threatening injuries, followed by open-surgery aortic repair. In the presence of severe concomitant injuries that contraindicate immediate surgery, however, medical treatment with blood pressure control followed by delayed open surgical repair has been proposed. ⁴ The present case illustrates the ongoing risk of rupture with this strategy and describes the successful treatment of traumatic aortic rupture by insertion of a thoracic endoprosthesis.

Case Report

A 45-year-old man was involved in a head-on automobile collision. On arrival at a community hospital, the patient was unconscious with normal vital signs. An intracerebral frontal hematoma and a possible isthmic rupture of the aorta were shown on computed tomographic (CT) examination (Fig. 1). The patient was transferred within 24 hours to our institution. He was intubated, and his blood pressure was controlled by medication. The initial chest radiograph was clear and showed multiple rib fractures. Because of the intracerebral hemorrhage, open repair was contraindicated. Angiography confirmed the contained isthmic rupture (Fig. 2). Treatment with an endoprosthesis was selected. However, no stents were readily available, because of the patient's aortic diameter of 22 to 24 mm. A 28- × 28- × 100-mm Talent™ stent graft (Medtronic Inc.; Santa Rosa, Calif) was to be shipped within 12 hours. Considering the shipment delay, we scheduled the patient for a semi-urgent stent-graft procedure the following morning. In the meantime, at 4 am, the patient experienced oxygenation problems and became hypotensive (blood pressure, 75/40 mmHg). A repeat chest radiograph showed a new, severe left hemothorax; over 1 L of frank blood was drained upon chest tube insertion (Fig. 3).

Fig. 1 Chest computed tomographic scan (A and B) shows the ruptured aortic isthmus.

Fig. 2 Aortogram confirms the ruptured aortic isthmus.

Fig. 3 Chest radiograph shows a new large left hemothorax.

The patient was emergently brought to the angiography suite. Under general anesthesia, the right common femoral artery was exposed for insertion of a 23F stent graft. The endoprosthesis, which had arrived a few hours earlier, was successfully deployed to seal the ruptured aorta. Immediate angiography showed good stent-graft position without any endoleak (Fig. 4). The total duration of the procedure was 1 hr, 45 min. After the procedure, the patient remained hemodynamically stable. Because of the neurologic trauma, he was weaned progressively from the ventilator during the following days. Two days after the procedure, a chest CT scan revealed good stent-graft positioning without any endoleak. The patient was transferred to a rehabilitation unit to recover from his neurologic trauma. A 3-month follow-up chest CT scan remained unchanged (Fig. 5). After 6 months, the patient had recovered fully from his neurologic trauma.

Fig. 4 Postprocedure aortogram shows good endoprosthesis position and absence of endoleak.

Fig. 5 Computed tomographic scan (A and B) immediately after stent-graft placement confirms stent position and absence of any endoleak.

Discussion

Blunt traumatic aortic rupture is a life-threatening injury. Diagnosis depends on a high index of suspicion, which is prompted mainly by the presence of a major deceleration injury. The natural history of BTAR was outlined more than 40 years ago in an autopsy series by Parmley and colleagues: ⁵ 86% of victims die at the scene of the accident or within 30 minutes of arrival at the hospital. Of the surviving victims, 20% die within 6 hours, 30% within 24 hours, and 75% within 8 days. Without treatment, only 2% survive to develop a chronic pseudoaneurysm.

Considering the poor natural history of this injury, BTAR has traditionally been treated with emergent surgical aortic repair. Recently, the progression outlined by Parmley's group has been challenged, ^6,7 because of the development of pharmacologic agents aimed at controlling systemic blood pressure. Some authors ⁴ have proposed that reducing aortic wall stress with short-acting β-blockers and meticulously controlling blood pressure could allow for a delay in open surgical aortic repair, particularly in patients who have concomitant life-threatening injuries that require life-saving procedures (such as laparotomy or embolization for pelvic artery bleeding). Moreover, in this era of modern pharmacologic treatment, the period for which the aortic repair can be safely delayed remains unknown. Moreover, other clinical studies have indicated that in-hospital death remains a problem with a delayed approach. ^1,8 Fabian and colleagues, ⁹ in a multicenter prospective study of 274 patients with BTAR, reported a 9% (n=24) rate of aortic rupture in patients who were in stable condition upon hospital arrival. Our case demonstrates the risk of early rupture even with the advantages of modern blood pressure control methods.

Endovascular treatment of aortic diseases was initially proposed by Parodi and associates ¹⁰ to treat abdominal aortic aneurysms. Subsequent use of stent grafts for the thoracic aorta was proposed by Dake and colleagues. ¹¹ Recent reports have shown excellent early results with the use of thoracic stent grafts for the treatment of BTAR. ^7,12,13 The advantages of endoluminal treatment include its minimal invasiveness and its rapidity, both of which decrease the morbidity and mortality rates associated with concomitant injuries and comorbid conditions. Furthermore, paraplegia after stent-graft placement is exceedingly rare and generally occurs with extensive coverage of the thoracic aorta combined with either an old or an adjunct abdominal aortic procedure. ¹⁴

Stent-graft placement presents various pitfalls. Vascular access requires a caliber of artery sufficient for the introduction of a 22F to 25F delivery system. Access other than the common femoral artery may be necessary in up to 20% or 30% of patients, which increases the complexity and morbidity of the procedure. Stent-graft placement requires angiography with injection of contrast media, which entails risks of allergic reactions and renal failure. The amount of contrast medium can be minimized by measuring the graft size (aorta size plus 15%–20%) on the enhanced chest CT scan.

Emergent stent-grafting procedures require readily available (on the shelf) stents. Standard-sized stents are available in diameters from 32 to 44 mm. Shipment from the manufacturer may delay the procedure by 24 to 48 hours. Custom-made stents may require up to 3 weeks to fashion. Therefore, graft availability can be problematic, as we found in the case presented.

Newer generations of stents will be available in a wider range of sizes. Moreover, early procedural complications, such as aortic rupture and stroke, remain low with the more flexible shafts and with meticulous manipulation of the device in the vicinity of the aortic tear and the aortic arch. It is anticipated that early endoleaks will be a rare occurrence with good graft size selection, since with BTAR cases, proximal and distal landing sites are composed of normal aorta. The mid- and long-term complications of thoracic endograft placement in patients with BTAR remain unknown. Provided that there are at least 1.5-cm proximal and distal portions of normal aorta available to secure the stent, stent migration and late endoleak (although reported with aneurysmal disease) should remain low in patients with BTAR. Stent fractures have been reported. However, to our knowledge, erosion of graft material with late endoleak has not been reported. Such mid- and long-term complications mandate a thorough and lifelong follow-up of patients treated with thoracic stent grafts.

The absolute role of stent grafts in the management of patients sustaining a BTAR is as yet undetermined. Young patients without comorbidities or severe associated injuries should be managed by open surgery with use of a distal perfusion technique such as left-heart bypass. Excellent surgical results and long-term outcome have been reported in such cases. ¹⁵ In patients with multiple blunt injuries and hemodynamic instability or injuries that contraindicate an open repair, such as severe pulmonary contusions or central nervous system injuries, a delayed open surgical approach or the placement of an endograft should be considered. We prefer an endoluminal approach in such patients to avoid early in-hospital rupture—a possibility illustrated in the present case. In addition, patients who sustain a BTAR and have severe comorbid conditions, such as chronic obstructive pulmonary disease, heart or renal failure, or shortened life expectancy (for example, with neoplasia), should be managed with stent-graft placement in the presence of adequate vascular access.

Finally, special circumstances in conjunction with BTAR, such as contaminated thoracic wounds, major burns, or established sepsis, should dictate the use of a less invasive approach, such as stent-graft insertion. Long-term follow-up of patients with BTAR treated with stent grafts will enable research groups to better determine the late outcome of this subgroup of patients. Moreover, improved graft technology in the upcoming years—such as thinner graft material to decrease the size of the introducer and better designed stents with differential radial forces in the aortic arch to enhance graft apposition—may minimize early and late complications. Only with rigorous follow-up will we clearly identify the indications for stent-graft use in patients with BTAR. If stent grafts are found to produce favorable long-term results in such patients, an endoluminal approach may prove to be the optimal treatment.