Robertson, FJ

Werring, DJ

English

David J Werring

Fergus J Robertson

Crossref

Practical Neurology

Emergency stenting for acute symptomatic carotid stenosis: dissecting the evidence

UCL Discovery

Emergency stenting for acute symptomatic carotid stenosis: dissecting the evidence  David J Werring1 and Fergus J Robertson2    1 Stroke Research Group, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom  2Lysholm Department of Neuroradiology, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG, United Kingdom   Corresponding author: Dr David Werring Stroke Research Group, Department of Brain Repair and Rehabilitation, UCL Institute of Neurology, Box 6, National Hospital for Neurology and Neurosurgery, Queen Square, London WC1N 3BG.  Tel: +44 (0)20 3448 3541 Email: d.werring@ucl.ac.uk Fax: +44 (0)2078338613   Keywords: stroke, carotid dissection, interventional neuroradiology  Word count: 697 excluding title page and references        Most neurologists, vascular neuroradiologists and stroke physicians encounter carotid  artery  dissection  (CAD)  regularly,  yet  its  management  remains challenging. The main goal is prevention of ischaemic stroke in the territory of the affected artery, usually due to thromboembolism, but also potentially due to critically  reduced  flow  in  the  dissected  arterial  segment,  so-called haemodynamic stroke.   Unfortunately, randomized controlled trial evidence is not available regarding the optimal medical treatment of extracranial dissection:  antiplatelet agents or anticoagulants are both considered reasonable options (1).   Why  is  carotid  dissection  still  a  treatment  challenge?  First,  like  stroke  itself, carotid  dissection  is  not  one  disease.  The  aetiology  (traumatic  versus spontaneous)  site  of  dissection  (intracranial  versus  extracranial),  degree  of luminal  stenosis  and  intracranial  collateral  circulation  varies  from  patient  to patient,  with  profound  effects  on  risk,  distribution  and  extent  of  resultant cerebral infarction. Second, although CAD accounts for about 20% of ischaemic strokes  in  younger  people,  recent  randomized  trials  in  CAD  had  major recruitment  difficulties  (1),  suggesting  that  a  definitive  answer  regarding optimum medical treatment is unlikely to emerge in the foreseeable future.   Where  patients  with  CAD  have  threatened  or  recurrent  secondary thromboembolic or haemodynamic cerebral ischaemia despite adequate medical therapy, or where medical treatment is contraindicated, there is considerable interest  in  endovascular  treatments.  Similarly  to  endovascular  treatment  of atherosclerotic carotid stenosis, a transarterial stent may be inserted with the aim  of  either  restoring  adequate  luminal  calibre  or  stabilizing  a  carotid pseudoaneurysm  (itself  a  potential  source  of  thromboemolism).  These techniques are well established, with first reported carotid stent treatment for arterial dissection by Matsuura et al in 1997 (2). High technical success rates have been reported in a number of subsequent small case series, well reviewed by Xianjun et al in 2013 (3). There are specific technical challenges in selecting the true lumen in the dissected vessel and in preventing distal embolisation of thrombus from the dissection flap. Current data suggests a procedural morbidity of approximately 5% (3,4,5).  Such studies seem liable to selection or publication bias, however, and true complication rates may be higher.  In  this  issue  of  Practical Neurology,  Korya  and  colleagues  describe  a  case  of extracranial carotid dissection with recurrent transient symptoms in the affected hemisphere, which the authors convincingly suggest were due to haemodynamic failure (i.e. reduced perfusion) resulting from the tight carotid artery stenosis. The patient had experienced transient focal neurological symptoms, related to posture and with a low systemic blood pressure, supporting the idea of reduced cerebral perfusion, rather than thromboembolism, as a mechanism. The patient’s symptoms stopped after a radiologically successful stenting procedure.   Although there is very limited high quality evidence for the effectiveness of acute carotid  artery  stenting  in  dissection,  this  case  highlights  its  potential  role  in carefully  selected  cases  where  haemodynamic  ischaemia  seems  to  be  the dominant problem. Of course, we can never know what would have happened without endovascular treatment, and given the rarity of this clinical situation, a randomized controlled trial will not be possible.   This case illustrates the challenges of treating uncommon cases in the field of stroke  medicine.  If  a  strictly  evidence-based  approach  is  taken,  this  patient should be managed with antithrombotic treatment only (either antiplatelets or anticoagulants). However, in this particular case, there was strong evidence for a haemodynamic  mechanism  for  the  recurrent  symptoms,  presumably  with  a substantial risk of early ischaemic stroke (although this is difficult to quantify) (6).  The patient’s attacks had continued despite antithrombotic therapy, and logical reasoning suggests that escalating the antithrombotic treatment further will  not  help  the  situation.  In  such  exceptional  cases,  it  seems  reasonable  to consider endovascular treatment.    But it is important that both doctors and patients appreciate the uncertainties and hazards of this course. Every effort should be made to systematically collect data on outcomes from such interventions, but the multidisciplinary approach to endovascular  treatment  can  make  this  challenging;  in  the  UK,  for  example, several carotid stent databases have been initiated in recent years, but none are currently comprehensive. Prospective outcome data should ideally be collected on all neuro-endovascular procedures undertaken outside randomized trials.   Although “do no harm” is a good starting point for all treatment decisions, this case report reminds us that in rarer clinical situations, evidence-based medicine will  not  always  give  the  answer,  and  that  careful  consideration  of  the pathophysiology, and technical skill, can lead to a good outcome.  References  1  Kennedy F, Lanfranconi S, Hicks C, et al. Antiplatelets vs anticoagulation for  dissection:  CADISS  nonrandomized  arm  and  meta-analysis.  Neurology 2012;79:686-689.  2. Matsuura JH, Rosenthal D, Jerius H, et al: Traumatic carotid artery dissection and  pseudoaneurysm  treated  with  endovascular  coils  and  stent.  J  Vasc  Surg 1997; 4: 339–343.  3. Xianjun H, Zhiming Z. A systematic review of endovascular management of internal carotid artery dissections. Interv Neurol. 2013 Sep;1(3-4):164-70.  4.  Cohen  JE,  Gomori  JM,  Itshayek  E,  et  al:  Single-center  experience  on endovascular  reconstruction  of  traumatic  internal  carotid  artery  dissection.  J Trauma Acute Care Surg 2012; 72: 216–221.  5.  Ohta  H,  Natarajan  SK,  Hauck  EF,  et  al:  Endovascular  stent  therapy  for extracranial and intracranial carotid artery dissection: single-center experience. J Neurosurg 2011; 115: 91–100.  6. Klijn CJ, Kappelle LJ. Haemodynamic stroke: clinical features, prognosis, and management. Lancet neurology 2010;9:1008-1017.    Contributorship  Dr Werring wrote the first draft. Dr Robertson reviewed the literature and made critical revisions, and approved the final version.   Funding  This work was undertaken at UCLH/UCL who received a proportion of funding from  the  Department  of  Health’s  NIHR  Biomedical  Research  Centres  funding scheme.  Competing interests  None.    

A systematic review of endovascular management of internal carotid artery dissections. Interv Neurol.

al: Traumatic carotid artery dissection and pseudoaneurysm treated with endovascular coils and stent. J Vasc Surg

Antiplatelets vs anticoagulation for dissection: CADISS nonrandomized arm and meta-analysis.

Endovascular stent therapy for extracranial and intracranial carotid artery dissection: single-center experience.

Itshayek E, et al: Single-center experience on endovascular reconstruction of traumatic internal carotid artery dissection. J Trauma Acute Care Surg

Emergency stenting for acute symptomatic carotid stenosis: dissecting the evidence

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