Prediction and Prevention of Stroke in Patients with Symptomatic Carotid Stenosis: The High-risk Period and the High-risk Patient

Cumulative risk of stroke following a TIA or minor stroke in the Oxford Vascular Study.²

The risk of recurrent stroke in all patients with TIA or non-disabling ischaemic stroke in the Oxford Vascular Study population who were found to have ≥50% symptomatic carotid stenosis censored prior to any endarterectomy (thick line).⁹ The dotted line shows this same risk excluding strokes that occurred prior to the patient seeking medical attention after the initial TIA or minor stroke. The thin line shows this latter risk excluding cases in whom carotid imaging was performed after the recurrence and showed a complete occlusion at that time.

The 90-day risk of recurrent stroke after first seeking medical attention in all patients with TIA or stroke referred to the EXPRESS Study Clinic in phase-1 (standard management) and in phase-2 (urgent treatment).¹¹

The absolute reduction with surgery in the five year risk of stroke and operative death in patients with 50–69% stenosis (yellow bar) and ≥70% stenosis without near-occlusion (blue bar) stratified by the time from last symptomatic event to randomisation in a pooled analysis of data from randomised trials of endarterectomy for recently symptomatic carotid stenosis.²⁰ The numbers above the bars indicate the actual absolute risk reduction.

The early risk of stroke by ABCD² score in pooled data from six independent cohorts of patients with TIA (4799 patients).²⁴ Stroke risks are shown at 2 days (black), 7 days (gray), 30 days (stippled), and 90 days (hashed).

Absolute reduction (ARR) with surgery in the 5-year risk of ipsilateral carotid territory ischaemic stroke and any stroke or death within 30 days after trial surgery according to predefined subgroup variables in an analysis of pooled data from the two largest randomised controlled trials of surgery for recently symptomatic carotid stenosis: (a) patients with 50–69% stenosis; (b) patients with ≥70% stenosis.²⁶

Validation in North American Symptomatic Carotid Endarterectomy Trial (NASCET) patients with 50–99% stenosis of the European Carotid Surgery Trial (ECST) model for the 5-year risk of ipsilateral ischaemic stroke on medical treatment. Predicted medical risk is plotted against observed risk of stroke in patients randomised to medial treatment in NASCET (squares) and against the observed operative risk of stroke and death in patients randomised to surgical treatment (diamonds).²⁹ Groups are quintiles of predicted risk. Error bars represent 95% confidence intervals.

A table of the predicted absolute risk of ipsilateral ischaemic stroke on medical treatment in ECST patients with recently symptomatic carotid stenosis derived from a Cox model based on six clinically important patient characteristics.²⁹