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Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Berlin, Germany
Received 13 March 2007; received in revised form 28 September 2007; accepted 1 October 2007.
* Corresponding author. Address: Department of Cardiothoracic and Vascular Surgery, Deutsches Herzzentrum Berlin, Augustenburger Platz 1, 13353 Berlin, Germany. Tel.: +49 30 4593 1938; fax: +49 30 4593 2100. (Email: buz{at}dhzb.de).
| Abstract |
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Key Words: Traumatic aortic rupture Conventional surgery Endovascular stent graft
| 1. Introduction |
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Endovascular stent grafting is a less invasive treatment for descending aortic pathologies and may be considered an alternative treatment option to conventional surgical repair. The advantages of endovascular treatment over conventional surgical repair of acute traumatic aortic rupture include the avoidance of thoracotomy and systemic heparinization. Therefore reduced perioperative morbidity and mortality rates can be expected.
The purpose of this retrospective study was to compare the results of endovascular treatment of traumatic aortic rupture with those of conventional surgical repair in acute settings.
| 2. Patients and methods |
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2.1.1 Surgical group and conventional surgical technique
In our study, 35 patients underwent conventional surgical repair of the traumatic aortic rupture. Thirty-one patients (87.8%) were treated within 7 days; in 19 of them emergency surgery was performed within 48 h after the trauma (in 16 patients within 24 h). Except for two patients who were operated on without cardiopulmonary bypass, in all patients, femorofemoral bypass was established with systemic heparinization. The thoracic aorta was approached through a posterolateral thoracotomy, with an incision in the fourth or fifth left intercostal space. The aorta proximal and distal to the injured segment was dissected and isolated circumferentially and was clamped between the left common carotid artery and the left subclavian artery or distal from the left subclavian artery in 27 patients (82%). A proximal anastomosis to the open distal arch in circulatory arrest and deep hypothermia was performed in 9 patients (26%). In 8 patients (24%), the aorta was repaired with direct suturing or patch plasty and in 25 patients (76%) a graft was interposed. After weaning from bypass, heparin was reversed with protamine sulphate.
2.1.2 Endovascular stent-graft group and treatment technique
We started thoracic endovascular stent grafting in 1999. After successful experiences with thoracic endovascular treatment in patients with descending aortic aneurysm, we increasingly performed endovascular stent grafting in patients with acute traumatic aortic rupture as a less invasive option for urgent or emergency treatment. In the last 7 years, 39 patients were treated with endovascular stent grafting. Thirty-four patients (87.1%) were treated within 7 days; of these, 29 patients underwent an emergency procedure within 48 h (23 patients within 24 h). We implanted three different commercially available thoracic stent grafts: the Talent (Medtronic Vascular, Santa Rosa, CA, USA) (n
= 27), E-vita (Jotec, Hechingen, Germany) (n
= 9), and Relay® (Bolton Medical, Sunrise, FL, USA) (n
= 3). In all patients, the rupture was located near or distal to the origin of the left subclavian artery. Two patients simultaneously received an additional stent graft for a second rupture, one in the distal thoracic aorta (Relay) (Figs. 1 and 2
) and one infrarenal with a bifurcated AneuRX stent graft (Medtronic). The diameter of the stent graft was oversized by 10–20% in relation to the diameter of the native aorta, to achieve a satisfactory tight seal. The endovascular stent grafts used were 28–42 mm in diameter and 100–150 mm in length.
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Postoperatively, the patients were referred back to the trauma centers for further treatment of the associated injuries. Chest X-ray and spiral CT angiography scan were performed before discharge and seen by our team. Follow-up was obtained by office visits, hospital reports, telephone interviews with patients, families and home physicians, and inquiries of local population registries. Two patients, who were transferred back to foreign countries, were lost to follow-up. Actuarial survival was calculated by the Kaplan–Meier method. However, CT scans in the follow-up period were only available in 10 of the 39 patients treated with endovascular stent grafts.
| 3. Results |
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The median follow-up for survivors was 6 years (range 0–15.6 years). During follow-up, no patient needed a redo operation. The survival rate at 1, 5, and 10 years was 75% (Fig. 3 ).
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In all but the case with the intraoperative conversion described above, the endovascular procedure was technically successful (97%). No paraplegia was observed related to the endovascular grafting.
In 5 of 20 patients where the LSA had been covered with the stent graft, a carotid–subclavian bypass was performed: in 4 cases after the endovascular procedure because of symptomatic arm ischemia at exercise or at rest and simultaneously in one 18-year-old man with spinal cord destruction due to a transverse fracture of the third thoracic vertebra in order to prevent ischemic arm problems in wheelchair rehabilitation. Two neurological complications occurred, in which an association with the occlusion of the LSA was suspected. The first case was that of a 42-year-old man after multiple trauma in a motorcycle accident including aortic transection and brain injury with coma at the scene of the accident. Huntington's chorea was previously known in this patient and may have contributed to the accident. The endograft was implanted 3 days after the accident. The postoperative CT scan showed complete exclusion of the aortic rupture and a partially occluded LSA with a mobile thrombus and in the brain multiple contusions, subdural hematoma, and subarachnoid hematoma plus a probably ischemic left cerebellar infarction. The patient did not recover from the brain injury and finally died 5 months after the accident. The second patient, a 57-year-old man, experienced an extremely severe car accident. He had a combination of blunt aortic transection, severe spinal cord and head injuries, and an unstable fracture of the fourth and fifth thoracic vertebra with paraplegia that was evident at the scene of the accident. The thoracic endograft was implanted 8 h after the accident, and the spine was then stabilized. When the patient awoke from anesthesia tetraplegia was noted. CT showed multiple defects and swelling in the brain stem and the left cerebellum. These defects were assumed to be partially due to some grade of ischemia or to the trauma. Neurosurgical decompression was performed, but the patient remained tetraplegic. He finally died 18 months after the accident due to tetraplegia-related pneumonia.
The mean follow-up time was 2.2 years (range 1–7.3). The survival rate was 86.4% at 1 and 81.6% at 5 years (Fig. 3). Three patients died during follow-up from late sequelae of associated injuries. Two are described above. One further patient (39-year-old male) died from graft infection with methicillin-resistant Staphylococcus aureus (MRSA) 8 months after the implantation, despite successful explantation of the device and interposition of a conventional Dacron graft. The initial course after multiple trauma had already been complicated by MRSA sepsis. Graft infection with MRSA was found at autopsy.
This was the only device-related complication observed during follow-up. No further endoleak, pseudoaneurysm, migration, or infection was found.
| 4. Discussion |
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Rousseau et al. [16] have transferred the concept of delayed elective treatment to endovascular repair as well. In this study, however, endovascular repair was performed immediately after trauma or as early as possible. Langanay et al. reported 20% of 50 patients with delayed surgical treatment between 6 and 60 days because of late diagnosis or coexisting life-threatening lesions without further aortic rupture or sudden death [17].
Four different surgical techniques have been described for the repair of an aortic isthmus rupture: clamp and sew, repair with distal perfusion by means of a Gott shunt, left heart bypass, and femorofemoral full cardiopulmonary bypass. The question of which of the four methods should be used for an acute traumatic aortic rupture has been discussed extensively during the last 20 years. In 1994 von Oppel published a meta-analysis of all English-language publications between 1972 and 1992 concerning this question [3]. A total of 985 patients who were operated upon with one of the three methods of distal perfusion had a paraplegia rate of 6.1% compared with 19.2% of the 443 patients who had direct clamping. A summary of studies on this issue published in the later period between 1995 and 1999 revealed similar results [2]. We especially refer to a large prospective multi-center study of the American Association for the Surgery of Trauma (AAST) directed by Fabian, in which 206 patients treated within 30 months were studied [18]. The rate of mortality was similar in the two groups (16.0% vs 17.3%) [2].
The influence of systemic heparinization on mortality and the risk of hemorrhage in such multiple-injured patients, particularly in patients with coexisting brain or pulmonary contusion, remain unclear [3,4,19] because no separate analysis has been made for different forms of distal perfusion.
The recent development of endovascular stent-graft prostheses for the treatment of thoracic aortic disease offers a potentially less invasive and safer alternative to open chest surgery in acute, high-risk surgical patients [20]. Endovascular stent grafting can be performed without aortic clamping and therefore may be applied in a larger number of patients, including hemodynamically unstable cases. The present study represents one of few high-volume single-center experiences in endovascular stent grafting of aortic traumatic rupture [14,19,21–24]. The goal of the endovascular stent grafting is to provide durable exclusion of the lesion while minimizing the morbidity and mortality of the open chest procedure including thoracotomy, one-lung ventilation, cardiopulmonary bypass, significant heparinization, aortic cross-clamping, and spinal cord ischemia. Although neurological complications may occur if the stent graft covers intercostal arteries, this possibility is limited because only few intercostals are involved with a short stent graft and the spinal artery rarely originates from the aortic isthmus.
There are only a few clinical studies reporting comparative analyses of endovascular treatment and conventional surgical repair in traumatic aortic rupture [19,21–23]. In all studies, a clear trend toward improved early outcomes in favor of endovascular treatment with lower mortality, paraplegia, and postoperative complication rate is observed in comparison to open chest surgery. Ott et al. reported a mortality rate of 16% and paraplegia rate of 16% after open repair of traumatic aortic rupture performed without distal perfusion. [22]. This study also demonstrated a clear trend toward an increased rate of complications, such as sepsis, myocardial infarction, acute respiratory distress syndrome, and prolonged ventilation with conventional surgical repair (66%) compared with endovascular treatment (17%).
In our experience, there was no paraplegia in the surgical or endovascular group related to the aortic procedure. Thirty-day mortality in the endovascular group was 7.7% compared to 21.2% in the conventional surgical group. Due to the small number this difference was not statistically significant. In our series the mortality rate in the conventional surgical group was related to the hemorrhagic complications or rapid deterioration of brain injuries during or after the procedure in four of seven patients who died. In all patients in the conventional surgical group who died, extracorporeal circulation with systemic heparinization was used. Additionally the postoperative complication rate was higher in the surgical group than in the endovascular group (30.3% vs 3%).
In view of these advantages in our practice, endovascular stent grafting has replaced step-by-step conventional surgery as the first-line procedure in managing blunt aortic trauma. Since the introduction of stent-graft therapy in 1999 only 10 patients were operated on conventionally, when the new method was not available at all times in the beginning, the last one in 2004. Currently only patients with rupture proximal to the LSA are excluded from the stent-graft technique; this applied to only one patient since 1999. By means of this new minimally invasive technique the past question of immediate or delayed repair is answered in favor of early repair, which avoids secondary rupture and eases further surgical and intensive care management of associated trauma. It further avoids the above-mentioned disadvantages of distal perfusion, which is necessary for a safe conventional procedure and to reduce paraplegia.
However, some issues remain unsolved. Sizing of the stent grafts is crucial and difficult. In these mainly young patients the aortic diameters are smaller than in the older aneurysm population, for whom the current stent grafts were originally designed. The diameter is variable according to the volume status of the acutely injured patient. Furthermore, the aortic arch is very steep in young patients, which may cause problems with the anchoring of the stent grafts. Collapse of stent grafts has been reported by several authors [25]. We did not experience this kind of complication, probably because we used Dacron/nitinol stent grafts with proximal bare springs, which adapt the proximal end of the stent graft better to the aortic arch. The ideal stent graft for aortic rupture has not yet been found, but the newer designs of this construction seem to be moving in the right direction.
For the same anatomic reasons, in many cases occlusion of the left subclavian artery can be necessary to ensure fixation of the stent graft in the proximal landing zone. If in doubt, the liberal use of this technique is recommended. Ischemic complications of the arm are rare and can be managed easily by extrathoracic carotid–subclavian bypass or transposition in the later phase of trauma management. However, the two neurological complications, which may contribute to the occlusion of the LSA, are a matter of concern. Both occurred in patients with severe spinal cord and brain trauma. Interestingly, no further neurological problems occurred in the patient with spinal cord rupture after we performed carotid–subclavian bypass in the same procedure in view of the practical considerations of further mobilization. This kind of simultaneous procedure may be considered at least in such a combination of injuries.
There seems to be a benefit in the endovascular group in terms of early mortality and complications related to the aortic procedure. However, secure conclusions cannot be drawn because the two groups are not truly comparative as the two methods were implemented in two different periods and the extent of concomitant injuries seems to be different. There was a trend toward more severe multiple injuries in the stent-graft group, although the difference in the overall injury severity score was not significant. This score, as all others, can only roughly express the severity of trauma, without an individual predictive value [8]. In early and 1-year mortality there seems to be a benefit for the endovascular patients. However, two patients died within 18 months from sequelae of severe cerebrospinal trauma, where the contribution of the endovascular procedure to the aorta remains unclear. One patient died from an MRSA infection of the stent graft, which was clearly acquired in the post-traumatic period, causing MRSA sepsis. The long-term survival is also not comparable due to the different number of patients at risk in the longer follow-up.
Finally, the long-term behavior of the stent-graft implants in mainly young trauma patients remains unclear. So far in all follow-up examinations we saw complete remodeling of the aorta at the rupture site without device-related complications, except in the one case of MRSA graft infection. Whether the early benefit of stent grafting in acute trauma will be sustained needs to be examined in further long-term studies.
| Appendix A |
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Dr D.C. Miller (Stanford, California, USA): Nine of the 31 had the left subclavian covered? Is it correct that 9 of the 31 patients required covering the left subclavian artery covered by the stent graft?
Dr Buz: Yes. In 9 of the 31 patients, the origin of the left subclavian artery was primarily overstented; 5 of them later needed bypass.
Dr Miller: Five needed revascularization?
Dr Buz: Yes.
Dr Miller: Because of arm claudication or posterior fossa cerebral insufficiency?
Dr Buz: The arm symptoms, i.e. arm ischemia at exercise or at rest, were the main indications for revascularization.
Dr Miller: It should be remembered that you cover the left subclavian ostium when you have to in an emergency situation, but you can get burned by a posterior fossa stroke if the left vertebral is large and the right vertebral is hypoplastic or occluded. We use the pre-procedure CTA to assess the vertebral artery anatomy and size to determine whether to revascularize (transposition preferred over carotid–subclavian bypass) the left subclavian system before or during the stent graft. Also remember that the left vertebral artery originates directly from the arch in about 2% of patients – a four-vessel arch – which can be very important.
Dr Buz: In patients with polytrauma, especially with severe head injury, the distinction of neurological complication related to occlusion of the left subclavian artery is difficult. But in this series with 31 patients we have not shown any neurological complication because of LSA occlusion. (Comment: In an oral presentation in Stockholm, we reported 31 patients treated with endovascular stent grafting. After the update of all patients until 2007, the paper reports on 39 patients (endovascular group). In this series we have two patients with neurological complications following LSA occlusion, reported in the paper).
Dr Miller: Yet.... As your experience gets larger it will happen. Believe me, this is a tricky and controversial subject.
Dr T. Sundt (Rochester, Minnesota, USA): I may have missed this. In your conventional group, how was the repair performed? Was it performed with left heart bypass? Did you give any heparin? Or did you use full cardiopulmonary bypass? I am concerned about your conclusions, because you seem to have an extraordinarily high CVA rate in your control group of conventional surgery. Im concerned about how much heparin was administered in the control group.
Dr Buz: We had five patient deaths on intracranial hemorrhage in this group. In all patients who were operated on with cardiopulmonary bypass, systemic heparinization was established.
Dr Sundt: In your control group, how was the operation done? Was full bypass with full heparinization used?
Dr Miller: Two were off-pump, or clamp and sew. What perfusion strategy for spinal cord and lower body protection was used for the others in the conventional surgery control group – left heart bypass, total bypass?
Dr Buz: We had only two patients without cardiopulmonary bypass in the conventional group. Except for two patients who were operated on without cardiopulmonary bypass, in all patients femorofemoral bypass was established. Out of them in 9 patients circulatory arrest and deep hypothermia were performed.
| Acknowledgments |
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| Footnotes |
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| References |
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This article has been cited by other articles:
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B. Marty Editorial comment: Management of traumatic aortic rupture: endovascular is the winner Eur. J. Cardiothorac. Surg., February 1, 2008; 33(2): 149 - 151. [Full Text] [PDF] |
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