Contents
34.1 Introduction . . . . 341
34.2 Conventional Surgical Treatment . . . . 341
34.2.1 Type of Repair . . . . 342
34.2.1.1 Direct Repair . . . . 342
34.2.1.2 Graft Interposition . . . . 342
34.2.2 Spinal Cord Protection During the Aortic Cross Clamp . . . . 342
34.2.3 Results of the Surgery . . . . 343
34.3 Endovascular Treatment . . . . 343
34.4 Conclusion . . . . 344
34.1 Introduction
Acute traumatic rupture of the aorta (ATRA) is a life- threatening complication of blunt chest traumas, which are mostly related to car crashes [1]. While more than 80% of patients showing this complication die on site, only 10±20% can be transferred alive to the emergency care unit. This represents four per 1,000 patients trans- ferred to the emergency care unit after car accidents [8].
In clinical series, the tear is located at the isthmus of the aorta in 90% of cases (Fig. 34.1). However, in ne- cropsy series, isthmic location represents only 50% of the cases, highlighting the high rate of death associated with other locations. Furthermore, 90% of patients show polytraumatism and have other life-threatening injuries.
In the past few decades, it was admitted that ATRA must be managed aggressively with immediate surgical repair. However, postoperative mortality remained high, mostly related to associated lesions. Moreover, different papers recently showed that surgical treatment could be delayed with very low risk of rupture, as long as ade- quate antihypertensive treatment is given [5, 6, 11]. Fi- nally, during the last decade, endovascular stent-graft- ing was established as an alternative to open surgery.
So, owing to these new approaches surgical treatment of ATRA has to be reevaluated.
34.2 Conventional Surgical Treatment
Surgical approach is made through a left postero-lateral thoracotomy in the fourth intercostal space, which al- lows access to the descending thoracic aorta as well as the heart and the trunk of the pulmonary artery. The goal of the surgical treatment is to clamp the aorta proximally and distally to the lesion, open the tear and
Surgical Treatment and Endovascular Issue in the Traumatic Rupture of the Descending Aorta
Pascal Leprince, Philippe Cluzel, Alain Pavie
34
Chapter
Fig. 34.1. Angiography showing isthmic location of the false an- eurysm
repair it. This treatment leads to two types of discus- sion: firstly, how to repair the lesion (direct repair or graft interposition) and, secondly, how to protect the spinal cord fromischemia?
34.2.1 Type of Repair 34.2.1.1 Direct Repair
Direct suture of the tear should be used whenever it can be done since it allows complete healing of the aor- tic wall. Direct repair (Fig. 34.2a,c) is easy in the case of incomplete rupture since there is no retraction of the two ends of the rupture. In complete rupture, direct su- ture can be helped by moving the proximal and the dis- tal part of the aorta. Direct repair becomes impossible in the case of old lesions or very complex and extensive lesions.
34.2.1.2 Graft Interposition
Replacement of the diseased segment of the aorta with a synthetic graft is easy to perform. However, graft in- terposition (Fig. 34.2b,d) may lead to the occurrence of several complications (inadequate length or diameter, anastomotic false aneurysm, infection) which can be surgically challenging to treat. This technique must be used only when direct suture is not possible.
34.2.2 Spinal Cord Protection During the Aortic Cross Clamp Three techniques can be used.
1. No protection: ªclamp and sew.º This method is the simplest. It does not require cardiopulmonary by- pass (CPB) and can be performed without heparin;
however, it is associated with a high risk of paraple- gia. The risk is proportional to the duration of the aortic cross clamp. Close to 0% under 20 min of
cross-clamp time, this risk goes up to 20, 60 and 100% for clamping times of 30, 60 and 90 min, re- spectively [4, 10]. Nowadays, this method is rarely used since patients with contraindications to CPB are postponed and/or treated with a covered stent graft.
2. Heparinized shunt (Fig. 34.3). A coated shunt can be used to bypass the interrupted segment of the aorta.
This allows perfusion of the distal aorta without using CPB and can be performed with no heparin.
However, the output of the shunt is not controlled;
in the case of sudden hemorrhage, it is not possible to immediately reinfuse the blood; the system does not prevent hemodynamic instability or oxygenation impairment that can occur during this surgery. With VII. Aortic Injury
342
Fig. 34.2.Types of lesions and repair:Aincomplete rupture with no retraction;Bcomplete rupture with retraction;Cdirect repair;
Dgraft interposition
Fig. 34.3.Passive shunt
this technique, the rate of paraplegia is about 11%
[4, 7, 10].
3. CPB (Fig. 34.4). Venous blood is drained fromthe right atriumthrough a cannula inserted through the femoral vein or from the pulmonary artery and is re- infused distally to the clamped segment, mostly into the femoral artery. The method has many advan- tages: oxygenation of the reinfused blood, control of the output, control of the bleeding through blood re- infusion directly with the CPB. This method allows us to repair complex lesions requiring a long cross- clamp time with a rate of paraplegia lower than 2%
[10]. However, the use of CPB requires the infusion of a high dose of heparin (3 mg/kg). This dramati- cally increases the risk of bleeding complications in patients with polytraumatism, particularly bleeding into the brain or the lungs.
34.2.3 Results of the Surgery
Postoperative mortality is reported to be between 6 and 35%, mainly related to associated lesions [4, 7, 10]. This is why, in the case of associated lesions with a risk of bleeding, the surgery is postponed and other lesions are treated primarily. Then the postoperative rate of death is lowered to 0±5% [5].
As described before, the rate of spinal cord ischemia related complication depends on the surgical technique.
A definitive lesion of the left laryngeal nerve is reported in 6±8% of cases [4, 7].
In the case of direct repair, the long-termprognosis is excellent with an ad integrum restitution of the aortic wall and preservation of growth potential in children and adolescents.
34.3 Endovascular Treatment
Over the last decade, the covered stent graft became more and more an alternative to open repair in patients with acute and chronic disease of the thoracic aorta. In 1999, Rousseau et al. [9] reported a series of five suba- cute and four chronic aortic traumatic ruptures treated with a covered stent graft. They reported 100% success of the exclusion of the false aneurysm, no death and only two major complications: one occlusion of the os- tiumof the left subclavian artery treated with stents and one transitory compression of the left main bronchus. Similar results were reported by Kato et al.
[3]. In a recent paper, Dunhamet al. [2] analyzed a to- tal of nine series published between 2001 and 2003 and reporting at least four patients with ATRA treated with a covered stent graft. These series represent a total of 68 patients with a technical success rate of 98.5%, an overall mortality of 5.9%, a graft-related death rate of 1.5%, an endoleak rate of 7.4% and no postoperative paralysis. These results compare favorably with those of surgical series.
The prerequisites for ATRA treatment with covered stent graft are essentially anatomical: a proximal and distal landing zone of at least 1.5-cmlength with a di- ameter not bigger than the available graft (46 mm), and an iliac artery diameter of at least 8 mm. If necessary the proximal landing zone can extend proximally to the left subclavian artery. This artery can be left occluded, the left upper limb being perfused through collaterals, or a carotid±suclavian bypass can be performed. In the review by Dunhamet al., there was one case of second- ary left armclaudication. Also, in their own series, the authors reported a case of posterior fossa infarction after occlusion of a dominant vertebral artery.
Long-termresults remain unknown. Most of the se- ries report a mean follow-up of less than 2 years. Pa- tients need to be followed with repeated imaging to sur- vey for stent-graft failure and secondary occurrence of an endoleak. If the occurrence of a secondary endoleak related to evolving aortic disease or covered stent-graft failure is a major concern, it may not be relevant in pa- tients with ATRA. Indeed, once the false aneurysmhas been excluded, the aortic tear heals underneath the stent and the false aneurysmshrinks and finally disap- pears (Fig. 34.5).
P. Leprince et al. Chapter 34Surgical Treatment and Endovascular Issue in the Traumatic Rupture of the Descending Aorta 343
Fig. 34.4.Cardiopulmonary bypass
34.4 Conclusion
ATRA is a life-threatening lesion but if the patient sur- vives the acute trauma the risk of secondary rupture re- mains low under strict blood-pressure control. Thus, treatment of the aortic lesion can be postponed particu- larly if the patient shows multiple injuries. The use of a covered stent graft appears promising with good im- mediate results and shrinking of the false aneurysm cavity occurring at midterm follow-up.
References
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2. DunhamMB, Zygun D et al. (2004) Endovascular stent grafts for acute blunt aortic injury. J Trauma 56:1173±
1178.
3. Kato N, Dake MD et al. (1997) Traumatic thoracic aortic aneurysm: treatment with endovascular stent-grafts. Radi- ology 205:657±662.
4. Kodali S, Jamieson WR et al. (1991) Traumatic rupture of the thoracic aorta. A 20-year review: 1969±1989. Circula- tion 84:III40±46.
5. Langanay T, Verhoye JP et al. (2002) Surgical treatment of acute traumatic rupture of the thoracic aorta a timing re- appraisal? Eur J Cardiothorac Surg 21:282±287.
6. Maggisano R, Nathens A et al. (1995) Traumatic rupture of the thoracic aorta: should one always operate immedi- ately? Ann Vasc Surg 9:44±52.
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discussion 125-116.
8. Pate JW, Fabian TC et al. (1995) Acute traumatic rupture of the aortic isthmus: repair with cardiopulmonary by- pass. Ann Thorac Surg 59:90±98; discussion 98±99.
9. Rousseau H, Soula P et al. (1999) Delayed treatment of traumatic rupture of the thoracic aorta with endoluminal covered stent. Circulation 99:498±504.
10. von Oppell UO, Dunne TT et al. (1994) Traumatic aortic rupture: twenty-year metaanalysis of mortality and risk of paraplegia. Ann Thorac Surg 58:585±593.
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967.
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Fig. 34.5.Computed tomography scan imaging showinga±cacute traumatic rupture of the aorta before treatment andd±f1-year follow-up after covered stent-graft placement. The false aneurysm disappeared
a b c
d e f
