Introduction

Traumatic rupture of thoracic aorta is uncommon; since it represents only 10% of all thoracic vascular traumas and usually involves the subisthmian portion of the aorta (85%)₁. It is burdened by immediate mortality rate higher than 80% and only 15-20% of the patients reach the hospital still alive₂. For many years, the gold standard treatment of these lesions has been the surgical approach through thoracotomy; however perioperative mortality and morbidity rates are still high, due to associated lesions. The endovascular treatment may represent an alternative approach to traditional surgery. The main advantages of this minimally invasive approach are the reduction of surgical trauma as well as minimal hemodynamic alterations.

Experience

During the last twelve months we observed 4 patients, mean age 22 years (range 17-27), affected by traumatic rupture of the descending thoracic aorta (Fig.1,2). In all cases lesions were a consequence of blunt trauma after a road traffic accidents. The mean Glasgow Coma Score was 8 (range 3-15). After performing resuscitation manoeuvres, all patients were investigated with total body CT (Computed Tomography) scans in order to complete the trauma staging and identify associated visceral lesions.

Figure 1

Figure 1: Ruptured aneurysm

Figure 2

Figure 2: Hematoma from rupture

At admission CT scans demonstrated the rupture of the descending thoracic aorta in three out of four cases, carachterized by a mediastinal hematoma originating distally from the left subclavian artery and extending for 3-5 cm with a mean diameter of 4 cm (range 3-5). In one case, the mediastinal hematoma was diagnosed 20 days after the admission at emergency accident ward. In this case the patient undergone emergency laparotomy to treat multiple visceral lesions, including splenic rupture, hepatic and mesenterial lacerations.

During ICU (Intensive Care Unit) stay the patient developed hemodynamic shock with no clear evidencies of bleeding; urgent CT scan was performed demonstrating the sub-hystmian rupture of the aorta. Among the three patients treated in the acute phase, the mean elapsed time between the E.R. (Emergency Room) recovery and the surgical treatment was 4 hours.

Procedures

Excluder endograft was used in all cases; the diameter was 28 mm in all cases, the lenght was 10 (3 cases) and 15 (1 cases). All the procedures were performed in the operating room under general anesthesia using DSA (Digital Subtraction Angiography) , systemic anticoagulation and antibiotic prophylaxis with chinolone and vancomycin. The common femoral artery (3 cases) and the external iliac artery (1 case) were surgically isolated. The mean operating time was 60 minutes while the endovascular procedure was 48 minutes. Only one endograft was needed in each case. Mean angiographic exposure time was 23 minutes and 120 cc of iodate enhancement was needed. All patients were submitted to spiral CT scan at 1,3,6 and 12 months and a chest X-ray in four projections in order to study the nitinol body of the stent. The mean follow-up was 6 months (range 3-15).

Results

Exclusion of the pseudoaneurysm was achieved in all cases (Fig.3-5).

Figure 3

Figure 3: Aortic flap

Figure 4

Figure 4: Exclusion of the pseudoaneurysm

Figure 5

Figure 5: Postimplant image

The mortality rate was null. No neurologic complications related to the endovascular procedure were observed. There were no endograft complications such as leak, migration, twisting or stenosis; in all patients the spiral CT scans control documented the complete exclusion of the aneurysm (Fig. 6,7) and the reabsorption of the aortic hematoma.

Figure 6

Figure 6: CT scan after 1 month

Figure 7

Figure 7: Final result of implant in place

Discussion

Traumatic rupture of the aorta is usually cause by a violent head-on collision during road traffic accident. The lesion is usually located at the subhystmian portion of the thoracic aorta originating after the origin of the left subclavian artery. The extension of the lesion may extend from subintimal hematoma and the complete rupture of the aortic wall. In rest of the cases the adventitial fibres and the adjacent structures circumscribe the hematoma into a pseudoaneurysm. Furthermore the lesions originate from subintimal bleeding and is the result of the deceleration forces, with torsion and compression that stretch the ascending aorta in the opposite direction from the descending aorta, and the increasing endoluminal pression¹,₃.

Diagnosis of pseudoaneurysm is always possible with spiral CT scans. It also provides the anatomic information to evaluate the feasibility of an endovascular procedure. Total body CT scans also diagnose visceral lesions frequently associated. The traditional surgical approach throughout thoracotomy represented the gold standard treatment for many years, but it is burdened by high mortality and morbidity rates (10-28%) which reach 60% in patient with associated visceral lesions₄,₅. Survival depends on the possibility to delay the treatment, as documented in large series, but according to the rest of Authors the accuracy in timing the surgical treatment and the selection of the patients is mandatory. Our experience confirmed that the endovascular approach is suitable in an emergency setting since it provide us to quickly stabilize the patient and is able to allow to treat the associated visceral lesions in the best systemic condition₇,₈ when compared to the traditional surgical approach. The endovascular treatment of the traumatic aneurysm seems to reduce paraplegia, cardiac and respiratory failure an fatal thromboembolism; it depends on the rapidity of the procedure, the less important surgical trauma, the reduced alterations of the hemodynamic state oft he patient due also due to the pressure control during the delivery of the device. These advantages are probably related to the rapidity of the procedure and the minimal surgical trauma. Although long-term results are not yet available larger series demonstrated the immediate efficacy, the rapidity and the less invasiveness of this approach.

Conclusion

The traumatic ruptures of the descending aorta are frequently the result of lacerations of the vascular wall due to mechanic stresses developed during blunt thoracic trauma. Immediate mortality rate is high and may reach 80%. Advantages of the endovascular procedures allows to quickly stabilize the patient reducing perioperative complications. In order to reach the best result, the lesions had to be diagnosed and treat as quickly as possible. Although long-term results are not yet available, our experience suggest that the endovascular approach to ruptured traumatic aneurysm is safe and feasible.

Correspondence to

Patrizio Castelli, Chief-Division of Vascular Surgery, Clinica Chirurgica University of Insubria, Ospedale di Circolo, Varese, Italy viale Borri 57, 21100, Varese, Italy phone number : 0332-278305 e-mail: patrizio.castelli@ospedale.varese.it