[Aneurysms of the subclavian artery].

INTRODUCTION

The Subclavian artery aneurysms are not a commonly seen peripheral aneurysm [1-5]-. We present the experience of the Institute of Cardiovascular Diseases of the Serbian Clinical Centre, Belgrade.

PATIENTS AND METHODS

Eight cases of subclavian artery aneurysms are presented. There were 3 male and 5 female patients, average age 51 (32-65) years. Of them 3 aneurysms were of atherosclerotic origin, 4 developed due to thoracic outlet syndrome (TOS), and one developed after intra-arterial drug injection. More details about our cases are presented in Table 1. One of our patients had intra-thoracal aneurysm (Case 3), and 7 had extra-thoracal aneurysm (Figure 1). Two aneurysms appeared as an asymptomatic pulsatile mass in supraclavicular space, and two with compression in the brachial plexus (Figure 2). Our patient 3 manifested skin necrosis and haemorrhage in supraclavicular region (Figure 3). The other 3 patients manifested acute hand ischaemia due to partial aneurysmal thrombosis and distal embolization. In these patients all distal arterial pulses were absent (Figures 4 and 5). In patient 8, besides hand ischaemia, transitory ischaemic attack (TIA) with contralateral hemiparesis also occurred. The reason was microembolization of ipsilateral carotid artery due to retrograde thrombo propagation. The diagnosis was established by selective angiography of the subclavian artery, and in 4 patients Duplex ultrasonography was also used. All patients were treated surgically. In 7 patients supraclavicular approach to subclavian artery was used, and in case 3 we used a combined trans-sternal and supraclavicular approach. In 7 patients a complete aneurysmal resection was performed, and in patient 5 due to infection aneurysm was excluded by proximal and distal arterial ligations. In this case arterial flow was reestablished by extra-atomic carotid axillary bypass with saphenous vein graft. In three patients with TOS, after aneurysmal resections, end-to-end anastomosis was performed. In patient 2 in whom aneurysm was also caused by TOS, saphenous vein graft was used for reconstruction. In all 4 patients with TOS, some kind of decompressive procedure at the thoracic outlet was also performed (two cervical and two first-rib resections using supraclavicular approach). In 3 patients with atherosclerotic subclavian artery aneurysms, PTFE graft was used for reconstruction (Figures 6 and 7).

RESULTS

One early postoperative complication occurred. It was embolism of the brachial artery which has been successfully treated by transbrachial embolectomy. The early patency rate was 88%. The patients were controlled using physical and Doppler ultrasonographic examinations 1, 3, 6, 12 months, and then every year postoperatively. The mean follow-up period was 3.6 (1-8) years. In that period one (13%) late complication was observed. It was thrombosis of the saphenous vein graft true aneurysm in our patient 2. This aneurysm was resected and replaced with PTFE graft. Postoperative histological examination showed connective tissue disorder of the vein wall. The long-term patency rate was 88%.

DISCUSSION

In most cases the true subclavian artery aneurysms are of atherosclerotic origin [1-4, 6, 7, 12]. We had 3 such cases. TOS is also often caused by subclavian artery true aneurysms [5, 13-17]. We had 4 such cases. Fibromuscular dysplasia [1, 18], cystic idiopathic medionecrosis [1, 19, 20], infection [1, 21, 22] and congenital disorders [23, 24], are rare causes of subclavian artery true aneurysms. Subclavian artery pseudoaneurysms can develop after different reconstructive vascular procedures [5, 28-41]. Subclavian artery aneurysms can rupture, thrombosis, embolize, or cause symptoms by local compression [6, 12, 41]. We had two cases with compression on brachial plexus. The compression on the trachea, oesophagus, laryngeal nerve, ganglion stellatum were also described [6, 12, 25, 42, 43]. Most subclavian artery aneurysms present ischaemic symptoms of