Surgical treatment of an acute left subclavian artery pseudoaneurysm caused by penetrating trauma

Sana CHATTI |

La tunisie chirurgicale - 2012 ; Vol 22

Resumé

Nous rapportons l’observation d’un peudo anevrysme de l’artère sous clavière gauche après un traumatisme ouvert du cou chez un jeune patient. En raison des risques de rupture et des complications d’ischémie secondaire, l’indication d’une reparation chirurgicale en urgence a été retenue. En peropératoire, il y’avait une forte présemption de communication entre la cavité anévrysmale et l’artère carotide primitive. Il a été réalisé une exclusion anevrysmale et une reconstruction artérielle par interposition d’un greffon prothétique. Les suites opératoires ont été favorables et l’angio-scanner postopératoire avait objectivé une réduction significative du pseudoanévrysme

Mots Clés

pseudoanévrysme, artère sous clavière gauche, traumatisme, chirurgie

Introduction :

Pseudoaneurysms of the subclavian artery are rare. They are traditionally treated by surgical resection and arterial reconstruction. In this article, we describe a case of an acute traumatic left subclavian pseudoaneurysm which was communicating with the common carotid artery. The patient underwent an open surgical repair with aneurismal exclusion associated to aorto-carotid and carotid to axillary bypasses.

Article

A 23-year-old male was admitted to the local hospital with a 5-cm knife stab wound to his left neck. Upon initial assessment, a large hematoma at the base of his left neck was noted and the patient was taken to the operating room for surgical exploration. There were no signs of active haemorrhage or identifiable vascular injury and the wound was simply sutured. Postoperatively the neck hematoma continued to enlarge and the patient was then referred to the cardio-vascular department of Rabta Hospital. Physical examination showed normal vital signs with equal blood pressure bilaterally. There was a 5-cm expanding painful mass at the base of the left neck. Cardiac, chest and neurologic examinations were normal. Evaluation by computed tomography scan revealed a 4,8-cm pseudoaneurysm of the proximal left subclavian artery (figure 1). The patient underwent open surgical repair through a median sternotomy combined with a left infraclavicular approach. The subclavian and axillary arteries were exposed and isolated. The direct approach of the pseudoaneurysm at the base of the neck was then performed. Due to the presence of inflammatory adhesions and fragile tissues we could not dissect free the aneurysm. The subclavian artery was clamped and at the opening of the aneurismal mass we were faced with major bleeding. At this point an alternative inflow from the common carotid artery was suspected. In fact, the bleeding was significantly reduced after carotid clamping. The subclavian and carotid arteries were ligated at their origin. An 8-mm PTFE graft was anastomosed to the left common carotid artery from the aortic arch, and then a prostheticaxillary bypass using also an 8-mm PTFE graft was performed. The carotid and axillary arteries were ligated proximal to the anastomoses. The aneurismal mass was sutured with the inflow bleeding which was judged moderate.

The postoperative course was uneventful and the patient was discharged home 5 days later. At 1 month followup, he had all his pulses and the neck mass disappeared. Computed tomography angiography showed patent grafts with persistent small pseudoaneurysm of 9 mm, filling via retrograde inflow in the left vertebral artery and a collateral vessel (figure 2). We were hopeful the pseudoaneurysm wouldn’t enlarge with reduction to the inflowing blood. The patient will be followed up with regular angiographic controls. In case of rapid growing or symptoms we will consider complete exclusion by percutaneous techniques.

Discussion

Penetrating subclavian artery injuries resulting in pseudoaneurysm formation are relatively uncommon (1-4). Their incidence ranges from 0,4 percent to 1 percent (1). They carry high risk of complications including distal embolization, compression, retrograde thrombus propagation and rupture which is by far the most serious and life-threatening complication (5). That’s why a prompt management of these lesions must be instituted.

Subclavian artery pseudoaneurysms have been historically treated with a conventional surgical approach. Advances in surgical treatment over the last century have provided feasible ways to treat any kind of lesion. The operative technique has evolved from simple ligation, to endoaneurysmorraphy, to resection and arterial reconstruction with or without graft interposition using autogenous vein or prosthetic graft. This procedure has been established as a gold standard treatment (6,7). Operative exposure depends on the size and location of the aneurysm. Intrathoracic right, proximal or ruptured subclavian artery pseudoaneurysms are best approached by median sternotomy or anterior thoracotomy. For aneurysms involving the distal subclavian artery, an anterior supraclavicular approach may be adequate, but, if more distal exposure is required, an infraclavicular counterincision can be made (7). Although surgical repair has been well demonstrated to be safe and durable, it is associated with its own morbidity and mortality, which ranges from 5% to 30% in various studies (2-4,8). Several technical factors complicate these vascular repairs including the need for ample incisions, distortion of anatomic plans by hematoma, the potential for neurovascular injuries and significant haemorrage (2,8). Given these limitations, less invasive techniques such as endovascular procedures have been recently developed. Since the first reports of stent graft treatment for arterial injuries in 1991, an increasing variety of traumatic vascular injuries are proving amenable to endovascular approach (2). The less invasive nature of endovascular aneurysm repair has the potential to reduce the mortality and morbidity of surgical procedures and may offer an alternative to patients with severe comorbidities. It is also associated with shorter operative time, less blood loss and shorter hospital stay (5). However, endovascular repair is not free of complications. These include rupture, dissection, immediate or late occlusion, stent or endoprosthesis fracture by compression, and conversion to open surgery in case of fail (2,3). Despite the attractive features of endovascular therapy, several authors restrict this approach to selected patients. Danetz et al. (2) described an algorithm to treat subclavian vascular injuries with conventional surgical repair versus endovascular treatment. Among the cohort of 40 patients presenting with axillosubclavian penetrating injuries, only 17 (43 percent) were potentially treatable with endovascular therapy. The most common contraindications to endovascular repair were hemodynamic instability, vessel transsection and no proximal vascular fixation site. The results are comparable to the conventional open surgery in properly selected patients (9). In some cases, combined open and endovascular treatment may be performed. Resch et al. (10) reported a case of right proximal subclavian aneurysm including the takeoff of the right vertebral artery in a patient who previously underwent cardiac surgery. This case was successfully treated with innominate to carotid artery stent grafting associated to carotid-subclavian bypass and a vertebral bypass. The location of the aneurysm at the bifurcation of the innominate artery prevented the placement of a stent graft in the subclavian artery alone. Bruen et al. (11) described four cases of proximal right subclavian aneurysm managed by hybrid technique combining stent grafting and extra-anatomical bypass so that mediastinal exposure and extensive surgical reconstruction were avoided. In our case, we chose a conventional open surgical repair to treat a posttraumatic proximal left subclavian pseudoaneurysm. Peroperatively, we had technical difficulties due to inflammatory atmosphere, including complete aneurismal dissection, ligation of collateral arteries and vertebral artery exposure. Furthermore, communication with the common carotid artery was suspected. We decided to exclude both subclavian and carotid vessels and perform arterial reconstruction with prosthetic interposition grafting. We were hopeful the aneurysm would thrombose with reduction to the inflowing blood and near stasis within the pseudoaneurysm. Computed tomography control revealed persistent filling essentially via the retrograde flow in the left vertebral artery. While recanalization of the pseudoaneurysm is uncommon, it has been reported. A similar case was described by Lee et al. (4) in which primary endovascular stent repair of a complex pseudoaneurysm crossing the subclavian, vertebral and internal mammary arteries had failed. With access to the pseudoaneurysm obstructed, ultrasound guided percutaneous thrombin injection was successfully performed. We believe that this procedure should be considered when initial pseudoaneurysm treatment fails to achieve complete thrombosis. Direct surgical exposure and embolization of the aneurismal cavity may also be performed. In conclusion, we believe that once diagnosed, patients with subclavian artery pseudoaneurysms should undergo either open, endovascular or hybrid repair given the risk of devastating complications and their prompt management may be achieved with low morbidity and mortality rates. Recent experience suggests that endovascular therapy is a safe alternative of treatment with good results in stable patients.

Références

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