Relationships Between Recent Intraplaque Hemorrhage and Stroke Risk Factors in Patients with Carotid Stenosis: the HIRISC Study

Objective: Intraplaque hemorrhage (IPH) is an emerging marker of plaque instability. However, little is known about the relationships between IPH and traditional risk factors and whether these relationships differ between symptomatic and asymptomatic disease.

Methods And Results: Two hundred thirty-four patients with symptomatic (n=114) or asymptomatic (n=120) carotid stenosis underwent high-resolution plaque magnetic resonance imaging. Seventy-five patients had recent IPH (symptomatic, 33%; asymptomatic, 31%). In symptomatic stenosis, recent IPH was independently associated with degree of stenosis (odds ratio [OR]=4.21, 1.61-10.98 for North American Symptomatic Carotid Endarterectomy Trial >35%; OR=2.92, 1.18-7.24 for European Carotid Surgery Trial >60%), qualifying event (OR=4.13; 1.11-15.32 for stroke or hemispheric transient ischemic attack ≥1 hour versus transient ischemic attack <1 hour or ocular symptoms), time from ischemic event (OR=6.65, 1.56-28.35 for ≤2 weeks; OR=2.24, 0.87-5.81 for 2-12 weeks versus >12 weeks; P for trend=0.03). In asymptomatic stenosis, IPH was only associated with stenosis severity >70% by ECST (OR=6.65; 1.95-22.73) but not by the NASCET method.

Conclusions: Our findings support the potential link between recent IPH and risk of ipsilateral stroke in symptomatic disease but also imply that prognostic studies should adjust for known stroke risk factors in multivariate analyses. In asymptomatic stenosis, the potential predictive value of recent IPH is less likely to be confounded by stroke risk factors.