345 35.2 Classification of Patients with Posttraumatic Injuries of the Aortic Isthmus or the Descending Aorta

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Contents

35.1 Introduction . . . . 345 35.2 Classification of Patients with Posttraumatic

Injuries of the Aortic Isthmus or the

Descending Aorta . . . . 346 35.3 Decision Algorithm . . . . 347 35.4 Results of a Multicenter Retrospective Study . . . . 347 35.5 Results from the Literature . . . . 348 35.6 Discussion . . . . 348 35.7 Conclusion . . . . 349

35.1 Introduction

The natural history of chronic isthmus and descending aorta posttraumatic false aneurysms has been directly related to the limitations of diagnostic imaging. The considerable progress made in noninvasive angiography during the last 10 years (mainly through the easy access to multislice computed tomography, CT, scanners) will probably contribute to the disappearance of chronic lesions discovered fortuitously by revealing the injuries at the acute stage.

The lesion is often an intimal tear, more or less cir- cumferential, misdiagnosed at the initial stage, which evolves towards a saccular pseudoaneurysm, incidentally demonstrated by a thoracic imaging study performed for another reason (Fig. 35.1). Some become symptomatic by a mechanism of compression (either

Classification

and Decision Algorithm

of Posttraumatic Chronic Lesions of the Isthmus

and the Descending Thoracic Aorta

Jean-Philippe Verhoye, Bertrand De Latour, Cyryl Kakon, Jean-Franois Heautot

35

Fig. 35.1. aAngiography during endovascular treatment of a chronic posttraumatic pseudoaneurysm, showing the stent-graft in its sheath.bAfter deployment, angiographic control shows the complete exclusion of the aneurysm

a b

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tracheo-bronchial or recurrent nerve) and are discovered by a targeted imaging study.

Today the progress in intensive care and the wide ac- cessibility to efficient vascular imaging studies in emergency situations have allowed better management of polytrauma patients. The advances in intensive care have induced an evolution of therapeutic strategy of acute ruptures of the aortic isthmus towards delayed surgery [1], the imaging advances have contributed to a drastic decrease, nearly disappear of misdiagnosed chronic false aneurysms.

According to the criteria defined by Langanay et al.

(Chap. 32), the only remaining surgical indication in an emergency is isolated lesions of less than 24 h, hemody- namically unstable, without associated lesion contrain- dicating a cardiopulmonary bypass.

It is easy to figure out now, in the precarious context of a polytrauma patient, that an isthmus lesion can be medically controlled and treated after a delay, to limit the inherent morbidity/mortality of the surgical procedure under cardiopulmonary bypass in an emergency.

It is now a consciously ªdelayed acuteº surgical management, where the lesion is voluntarily ªchronicized.º

In spite of intensive care and careful follow-up, patients have suffered ruptures during these periods of ªcontrolled chronicization.º

Stent-grafts will probably help to prevent these sudden early ruptures while allowing a quick initial treatment of the lesion. This technique does not command systemic anticoagulation during or after the procedure, thus limiting the hemorrhagic complications in polytrauma patients. Encouraging results are currently being published [1, 2]. The challenge of this new management is linked to the midterm and long-term exclusion of the lesion in a definitive way like conventional surgery does.

The nonendothelialization of the stent-graft and the increasing aortic diameter with the patient's age carries a risk of late type I endoleaks which could potentially activate a degeneration of the initial lesion into a chronic false aneurysm. In this case, the nonendothelialization would be an advantage by facilitating the surgical explantation of the stent-graft and conventional repair of the aorta, even a long time after the endovascular procedure (Fig. 35.2).

The endovascular therapy is a major step in the history of therapeutic management of traumatic injuries of the isthmus and the descending aorta. Because of this trend, it has appeared necessary to us to propose a new classification of these lesions, to better define the management, whichever therapeutic solution is used. The classification must allow us to define stages for the pur- pose of comparing therapeutic results among homoge- neous groups of patients. It must also propose a decision algorithmto better select the most appropriate therapeutic choice with respect to the priorities in patient management.

35.2 Classification of Patients with Posttraumatic Injuries of the Aortic Isthmus or the Descending Aorta

Class I: acute (<48 h)

A: Isolated lesion B: Polytrauma

1: Stable 2: Unstable

Class I corresponds to a post-raumatic lesion of the isthmus or the descending aorta, with two subclasses:

Fig. 35.2. aCT angiography. Control 6 months after stent-graft treatment of a chronic posttraumatic pseudoaneurysm, showing a type I endoleak. The endoleak was monitored and spontaneously resolved, but at 3 years the patient suffered bronchial

compression due to endotension. Surgical conversion had to be performed (graft interposition and aneurysm thrombus resec- tion).bCT angiography, 3D reconstruction, volume rendering.

Control after surgical conversion

a b

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the lesion is either isolated (A) or associated with others injuries (polytrauma, B), and the patient is he- modynamically stable (1) or unstable (2).

Class II: delayed acute (>48 h)

A: Isolated lesion B: Polytrauma

1: Stable 2: Unstable

Class II corresponds to a lesion initially not treated because of misdiagnosis or surgical contraindication. The lesion is either isolated (A) or associated with other injuries (polytrauma, B), and the patient is hemodynami- cally stable (1) or unstable (2).

Class III: incidental chronic A: Stable diameters/unknown

evolutivity B: Increasing

1: Asymptomatic 2: Symptomatic

Class III corresponds to an incidental posttraumatic chronic pseudoaneurysmof the isthmus or the descending aorta. This lesion can be stable, or its evolutivity unknown (A), or increasing (more than 1 cm/year) or a contained ruptured (B). It can also be asymptomatic (1) or symptomatic (dysphonia, cough, bronchi- tis, chest pain, pleural effusion) (2).

35.3 Decision Algorithm

Starting fromthis classification, it is possible to define a decision algorithmtaking into account the surgical and endovascular results of the last 10 years. Surgery assisted by cardiopulmonary bypass has proven its long-termefficacy at the cost of reduced postoperative morbidity/mortality in patients younger than 70, with no major risk factor.

The follow-up for patients treated by a stent-graft is hardly 8 years in the most expert teams, but the best in- dications are already being defined. To deploy a stent- graft is not to cure because we know now that stent- grafts do not get endothelialized, which can cause mid- termand long-termendoleaks and endotension, which reactivate the aneurysmal process and the risk of sudden rupture.

Regarding this technique, the current strategy is rather based on getting over the acute phase to avoid rupture in the critical context of a polytrauma patient.

The surgical access is limited to the groin (depending on the quality of the iliac arteries) even if it is prefer- able to performthe operation in an operating room with cardiopulmonary bypass at hand. According to the

patient status, it can be performed in an acute emergency, a delayed emergency, or after a period of controlled chronicization.

A careful CT scan follow-up is mandatory, at 1 and 6 months, and yearly thereafter, for the current genera- tions of stent-grafts. The patients must be informed of this requisite and that late disorders can occur, which can then lead to elective surgery.

The other field of endovascular treatment is the management of patients older than 70, in which surgery carries a significantly higher risk. The lesions are often incidentally diagnosed, asymptomatic, and often large (maximum diameter frequently more than 60 mm), after trauma occurred several decades before. The risk of rupture of these lesions is not known, and endovascular solution seems a better first choice for these patients.

So, a therapeutic decision algorithmis proposed is as follows:

Class I, II A1<70 years old Surgery except contra-indication A1>70 years old,

A2 and B Stent-graft

Class III A1 CT follow-up

A2<70 years old Surgery, except contra-indication A2>70 years, B Stent-graft

35.4 Results

of a Multicenter Retrospective Study

In order to validate the appropriateness of this classification and algorithm, a retrospective study was con- ducted in six French university centers. We report the midterm results for 47 class II and III patients. The aortic injuries were diagnosed at the time of the trauma (63.8%, n=30), or incidentally (36.2%, n=17). Between January 1996 and June 2004, endovascular repair of the descending thoracic aorta with commercially available stent-grafts was performed in 47 patients (mean age, 43Ô19 years) at an average of 6Ô11 years after the in- jury. Because of comorbidities, eight patients (17%) were judged not to be reasonable surgical candidates for a conventional surgical approach. Follow-up was 100% complete and averaged 18Ô13 months.

Stent-graft deployment was successful in all patients.

No early death occurred. One late transient paraparesia occurred. Two patients had a primary endoleak, one type I and one type II which spontaneously resolved at 1 and 6 months, respectively. Two endotensions were described after 36 months (currently being monitored) and 30 months (surgical conversion). The actuarial sur- vival estimates at 1 and 3 years were 97.7Ô2.3 and

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87.9Ô9.5%, respectively. The actuarial freedomfromre- intervention on the descending thoracic aorta was 100 and 90.9Ô8.7% at 1 and 3 years, respectively. The actuarial freedomfromtreatment failure (a conservative, all-encompassing performance indicator including endoleak, device mechanical fault, reintervention, late aortic-related death, or sudden, unexplained late death) at 1 and 3 years was 97.7Ô2.3 and 74.6Ô11.9, respectively.

The mean diameter of the pseudoaneurysm was 44Ô 18 mm before treatment and decreased significantly (p<0.001) to 40Ô18 mm after treatment.

35.5 Results from the Literature

These results from the literature are summarized in Ta- bles 35.1 and 35.2.

35.6 Discussion

Elective surgery of posttraumatic pseudoaneurysms has proven efficient. Direct suturing with cardiopulmonary bypass is possible in nearly half of cases. It carries a low mortality, and a low renal and respiratory morbidity. The rate of paraplegia is close to zero in the best se- ries. So, in these cases, the only advantage of endovascular techniques is the mini-invasivity. Stent-graft treatment has proven its feasibility. As the adjacent aortic wall is normal, nondegenerative, late endoleaks are more unlikely than in cases of degenerative aneurysms [7]. The limits are known. Long proximal necks and long one-piece stent-grafts are required to achieve good preliminary results. This will probably make more fre- quent prior surgical bypass of the left supra-aortic vessels (Fig. 35.3) in order (1) to get a longer proximal neck and (2) to maintain the patency of the left subclavian artery, essential for spinal cord blood perfusion as has been shown by surgery studies, because long stent- grafts will increase the risk of paraplegia if the left subclavian artery has to be intentionally occluded [10].

Table 35.1. Surgical results fromthe literature Finkel-

meyer et al. [3]

McCollum et al. [4] Soyer

et al. [5] Roques et al.

[6]

Patients (N) 413 50 20 19

Operative

mortality (%) 4.6 4 0 0

Respiratory

complications (%) 0.7 2 ± 26

Paraplegia (%) 1.4 ± ± ±

Paraparesia (%) 1.4 ± 15 ±

Stroke (%) 1.1 ± ± ±

Renal failure (%) 1.4 2 ± ±

Recurrent

paralysis (%) 6.7 4 ± 10

Table 35.2. Endovascular results fromthe literature Demers

et al. [7] Kato

et al. [8] Rousseau et al. [9] French

multicenter study

Patients (N) 15 10 8 47

Operative mortality 1 0 0 0

Respiratory

complications ± 1 1 ±

Paraplegia ± ± ± 0

Paraparesia ± ± ± 1

Stroke ± ± ± ±

Renal failure ± ± ± ±

Recurrent paralysis ± ± ± ±

Vascular access

complication ± 1 1 2

Fig. 35.3. Computed tomography (CT) angiography, 3D reconstruction, volume rendering. Control of a stent-graft 4 years after endovascular treatment of a chronic posttraumatic pseudoaneurysm. The left supra-aortic vessels have been bypassed (arrow), in order to get a longer proximal neck

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35.7 Conclusion

The management of acute and chronic lesions of the isthmus and the descending aorta has markedly evolved with advances of imaging and intensive care.

Endovascular techniques, limiting the morbidity of the treatment at the acute, delayed acute and controlled chronic phases in unstable and trauma patients, do not preclude delayed surgical options, currently the gold standard for definitive lesion exclusion.

The endovascular techniques also seema good op- tion in incidental lesions, with favourable anatomy, in elderly patients.

It must be kept in mind that currently to deploy is not to cure, and that life-long imaging follow-up is necessary.

Acknowledgements. Frdric Thony (University Hospi- tal, Grenoble), Herv Rousseau (University Hospital, Toulouse), Pascal Leprince (University Hospital, Paris Salpetri re), Philippe Douek (University Hospital, Lyon) and Louis Boyer (University Hospital, Clermont-Fer- rand) are thanked for their contribution to the French multicenter retrospective study of endovascular treatment of chronic posttraumatic aortic false aneurysms.

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