Australia & New Zealand Society of Vascular Surgeons

Introduction and Objective The management of carotid artery stenosis has been controversial since the first carotid endarterectomy (CEA). Strokes with intervention and absence of neurological events after known spontaneous internal carotid artery occlusions underscore the dilemma of prophylactic intervention for carotid stenosis. This question was answered by the European Carotid Endarterectomy Study (ECES) and the North American Study on Carotid Endarterectomy Trial (NASCET). However, the advent of carotid angioplasty and stenting (CAP) interventionists reignited controversy. Technology advances and trial exclusions meant that the parameters and risk benefit analysis changed – especially with the results of the Sapphire Trial and the use of embolic protection devices. Interpretation of the trials is based on intra-arterial contrast angiography. This implies the argument that the guidelines for intervention cannot be extrapolated to other imaging modalities but it does carry a small risk of stroke. Magnetic resonance arterial imaging (MRA) and diffusion weighted images (DWI) are able to reliably show the anatomy, the lesion and recent ischaemic events. While MRA overestimates the degree of stenosis, Duplex Doppler Ultrasound is accepted by many to determine the degree of stenosis. The non-invasive combination shifts the risk benefit analysis and enhances the objectivity of assessing symptoms and neurological events. A surgeon who can offer either CEA or CAP has the dilemma of choosing the optimum method of intervention for an individual patient. Guidelines are necessary to determine choice of procedure as well as indication to intervene. Target vessel access, lesion morphology and behaviour and arterial anatomy are parameters that have not been assessed by clinical trial. Anecdotal experience lists all of these as parameters that may affect outcome and hence risk benefit analysis and advice to patients. MRA and DWI’s enable non-invasive assessment of the arch of the aorta and its branches, the extracranial and intracranial vessels and identification of old and recent ischaemic events. These techniques mean that the indications to intervene can be more reliably determined, based on the Trial criteria. The method of intervention, medical management alone, CEA or CAP can be chosen. After clinical evaluation, an assessment is made of the carotid stenosis with Duplex Doppler Ultrasound to determine whether there are indications to intervene. If the indications are strong or doubtful, further assessment is performed using magnetic resonance technology. The following protocol developed within the Mount Hospital (Perth, Western Australia) provides one approach. Extracranial MRA – Assess arch and carotid lesion – Vessel redundancy – Tandem lesions Intracranial MRA – T1/T2/DW1 – for base line assessment of the brain and intracranial circulation *Patient advised of indications and options of management. Procedure Determined by morphology of the anatomy, pathoanatomy and patient input a). CEA – under local anaesthetic; without shunting b). CAP – If suitable for angioplasty and stenting – performed with embolic protection without prior four vessel or intracranial angiography. Single carotid intra-arterial action intended angiography is done to confirm the lesion, perform the procedure and for completion assessment. Post-procedure Clinical assessment with DWI’s and ultrasound of the treated area Follow-up Stent surveillance with ultrasound It is likely that carotid intervention will be controversial because stroke prophylaxis works on a risk benefit analysis where the behaviour of a lesion-complex is unpredictable. A rational, multidisciplinary approach has provided a stronger basis for management plans. The modern vascular surgeon needs to be multi-skilled or part of a multidisciplinary team to provide the options.