CASE REPORT

An 81-year-old lady presented to clinic in March with a 2-month history of a pulsatile left neck mass, with associated dysphagia, and weight loss. There was mild pain with no overlying skin changes. Of note, she had a background of previous multiple strokes and of a left CEA performed in 2014 to treat a symptomatic carotid artery stenosis. She was known to have an occluded left common carotid artery as far as the circle of Willis in her CT angiogram and duplex ultrasound in late 2019 when she presented with left hemispheric stroke. On examination there was a palpable tender pulsatile mass measuring 2.5x 3cm. She complained of associated compressive symptoms of dysphagia that was contributing to malnutrition. A duplex US was performed which demonstrated a vascularized mass with difficulty delineating the wall. It was decided at this point to perform a CT angiogram which demonstrated a left carotid pseudoaneurysm measuring 3.3x 3.5cm with patch disruption. The previously occluded left carotid system was now patent from the origin of the common carotid artery to the circle of Willis, with occluded external carotid artery. The diameter of the internal carotid artery was 5mm. her inflammatory markers were slightly elevated. Our approach was to improve her general condition and optimize her for surgical intervention. We adopted the hybrid approach to treat this pseudoaneurysm. This was done with a trans-cervical carotid artery stenting followed simultaneously by open carotid pseudoaneurysm repair using interposition vein bypass. The patient was positioned supine with right tilted extended neck in a hybrid operating theatre. A transcervical carotid artery stent approach was accessed initially by doing small vertical proximal carotid cutdown at base the neck and inserting a 7 French hydrophilic sheath into the proximal left common carotid artery (CCA). The direct angiography revealed left carotid patch pseudoaneurysm with continuity of left internal carotid artery (ICA) intracranially. A bolus 5,000 intravenous unfractionated heparin was given. We placed two of covered self-expandable Viabhan stents from the common carotid artery as far as the ICA (W. L. Gore & Associates, Arizona, USA) to temporarily seal the pseudoaneurysm. We performed negative suction while we deployed the stents using suction syringe from sheath sideway combined with left proximal CCA clamping. The negative suction technique was used in order to reduce improve the retrograde flow from the ICA and reduce the distal embolization while stents deployment (see Fig 1). We removed the 7fr sheath with purse string monofilament stitch to repair the carotid puncture site. At that time the left great saphenous vein was harvested from the right groin. We then started the open exploration of the carotid pseudoaneurysm. The initial carotid vertical incision was extended cranially until the mastoid process over the left carotid pseudoaneurysm. Dissection was performed carefully avoiding nerve injury. The pseudoaneurysm was exposed and revealed a disrupted Dacron graft with combined pus and blood clots noted. The bare metal stents inserted were visible at this point with no active bleeding (see Fig 2). Distal ICA control was achieved (see Fig 3). We routinely use the ICA stump pressure combined with retrograde ICA blood backflow to check the intracranial circulation prior to and after CCA clamping. Also, the patient has intact right carotid arterial tree and circle of Willis with no obvious contralateral ICA stenosis. the stump pressure was 52 mmHg with good ICA blood backflow after CCA clamping. We decided to avoid using the carotid shunt in addition to maintaining the systolic blood pressure between (160-180 mmHg). The affected arterial segment was then excised along with the previously inserted stents with good ICA arterial backflow seen (see Fig 4, 6). In situ End-to-end anastomosis was performed between the CCA and the proximal end of the vein bypass followed by ICA anastomosis with distal end of the harvested vein (see Fig 5). A sternocleidomastoid muscle flap was used to cover the interposition vein bypass as a secondary prevention of graft infection with good hemostasis. Surprisingly, there were no organism grown in the tissue and the Dacron patch culture that has been sent intraoperatively. Postoperatively, the patient recovered well and required 24 hours monitoring in high dependency unit. Dual anti-platelet was started as well as antibiotics with a plan to complete 48 hours course. She continued to receive multidisciplinary input from physiotherapy, occupational therapy, and dietician to enhance recovery. A repeat CT angiogram showed a widely patent graft and left ICA. She had no residual symptoms or dysphagia on her 6 weeks routine follow up course with patent interposition carotid bypass on the duplex scan.