Differences between CAS and CEA in the pathophysiological mechanism of procedural stroke GJ de Borst Department of Vascular Surgery

Background Most data on CAS vs CEA focused on clinical outcomes Few data characterizing the strokes that occur during carotid revascularization (and especially CAS) Thus limiting understanding the potential mechanisms of procedural stroke … Fairman R, et al Ann Surg 2007 / de Borst et al EJVES 2001

Micro-embolisation harmless ??

Timing of procedural stroke Intra-operative stroke: 1) apparent at awakening 2) intra-procedural symptoms (in the awake patient) Post-operative stroke: 1) Symptom free interval between awakening and start of symptoms 2) Symptom free interval between procedure and start of symptoms

Etiology (1) Intra-operative stroke Embolisation spontaneous (instable plaque) Dissection phase Shunt insertion Air embolisation (shunt dysfunction) Embolisation endarterectomized zone Thrombosis Peri shunt thrombosis On table carotid thrombosis Other Unstable haemodynamics (no shunt, uncontrolled hypotension). Haemodynamic failure: shunt dysfunction

Etiology(2) Post-operative stroke Embolisation Embolisation from endarterectomized zone Embolisation from external carotid artery Thrombosis Secundary to technical failure Secundary to hypotension Secundary to carotid siphon pathology Secundary to disturbed haemostasis Other Primary intracerebral bleeding Haemorrhagic transformation of ischemic cerebral infarction Hyperperfusion syndrome

Minor, major stroke, and death within 7 days Up to 1990 (only EEG) : 4.8% intra operative ?? % post operative from 1990 (EEG + TCD) : 1.0% intra operative 2.4% post operative de Borst GJ et al. Eur J Vasc Endovasc Surg Clinical outcome following CEA (1)

Clinical outcome following CEA (2) … Intra Operative Stroke (IOS)4% 1992 – 1994 TCD / angioscopy / routine shunting » IOS1% » POS? 1994 – 1996 Intimal flap correction, thrombus removal »IOS0% »POS2.8% Lennard N et al. EJVES 1999 Naylor AR et al. J Vasc Surg 2000

Goal ? Descriptors of stroke severity, location, and timing may provide insight into the mechanistic causes : Major vs minor Ipsilateral vs contralateral Ischemic vs haemorrhagic Intra-procedural vs post procedural Pre-discharge vs post-discharge

Goal ? Based on : intraoperative cerebral monitoring, postop cerebral monitoring, blood pressure data, angiography related events, postop imaging (treated area still patent ?), or re- exploration: Most probable mechanism of stroke ? Potential problem: no standardized assessment of patients with procedural stroke……..