Impacts of internal carotid artery stenosis degree on the outcomes of ischemic stroke patients

Abstract

BackgroundAtherosclerosis of internal carotid artery (ICA) is a well-recognized cause ofcerebral infarction. However, previous studies were not systematically analyzedthe impacts of the ICA stenosis degree on the outcome of ischemic strokepatients. The objective of this study was to clarify the relationship betweeninfarction patterns and prognosis according to the degree of ICA stenosis.MethodsFrom the Yonsei Stroke Registry, 3686 consecutive stroke patients wererecruited from January 2004 to December 2009. According to the criteria,finally 264 patients with ICA stenosis only were enrolled. Infarction patternswere determined using diffusion weighted MRI images (DWI). DWI patterns were categorized into five categories: (1) subcortical (2) territorial (3) confluentinfarction with additional lesion (4) disseminated, and (5) borderzoneinfarctions. Univariate and multivariate analyses were performed to evaluate theassociation between the degree of ICA stenosis and various factors includinginitial stroke severity, functional outcomes at discharge and at 3 months.ResultsSubcortical infarction was observed in 61.5% of the patients with <50% ICAstenosis. In the complete occlusion group, confluent infarction with additionallesions (41.3%) and territorial infarction (24.0%) were common. All patientswith near occlusion group showed either disseminated pattern (70%) orconfluent infarction with additional lesion (30%).Initial stroke severity measured by NIHSS was associated with older age, ICAcomplete occlusion, territorial and confluent patterns. Poor outcome atdischarge (mRS≥3) was independently associated with initial NIHSS score andearly neurological deterioration (END) after adjustment with ICA stenosis andDWI patterns. Older age is also the predictive factor of poor outcome at 3months.Comparing with <50% stenosis group, complete ICA occlusion group had7.53-fold (CI 3.88-14.62) higher initial stroke severity measured by NIHSSscore, 7.45-fold (CI 3.83-14.52) higher mRS at discharge and 5.95-fold (CI3.10-11.40) higher mRS at 3 months. Likewise, comparing with 50-99%stenosis group, complete ICA occlusion group showed a 6.14-fold (CI 2.98-12.65) higher initial NIHSS score, 5.88-fold (CI 2.85-12.12) higher mRS atdischarge, 5.67-fold (CI 2.74-11.73) higher mRS at 3 months. Compared withnear occlusion group, initial NIHSS score is 4.96-fold (CI 1.18-20.86) higher incomplete occlusion group but mRS at discharge and mRS at 3 months were notdifferent.Conclusionswe demonstrated that infarction patterns were highly different depending onthe degree of ICA stenosis and the patients with complete ICA occlusionshowed significantly poor outcomes comparing with other degree of stenosis.Different infarction pattern according to degree of ICA stenosis might beassociated with outcome in patients with carotid diseases.