Background
Intracranial Atherosclerotic Disease (ICAD) is an important cause of stroke with a prevalence of up to 40%. In New Zealand (NZ), limited information is available on ICAD prevalence and variation by ethnicity.
Aim
The aim of this study was to evaluate the prevalence of ICAD at our tertiary hospital-based service and its relationship with ethnicity.
Methods
We retrospectively reviewed electronic records of patients presenting with ischaemic stroke/TIA between January 2018 and December 2020 to the Wellington Region, NZ. Review included documented risk factors and TOAST criteria identification. Symptomatic ICAD was defined as single large intracranial vessel stenosis/occlusion in the symptomatic vascular bed with calcification and no alternative explanation for event. Associations were explored using logistic regression (predictors: sex, age, ethnicity, diabetes, HT, Lipid and smoking).
Results
Of the 581 patients, 9.0% had symptomatic ICAD and 27.8% had ICAD more than 50% stenosis (asymptomatic and symptomatic). There was no association between the proportion of those with symptomatic ICAD and ethnicity, p=0.979. An intracranial stenosis of greater than 50% was associated with increasing age p=0.0004; and the presence of diabetes: OR=2.46 (95% CI: 1.58 to 3.83), p<0.001. An interaction between age and ethnicity was found suggesting the age-associated rise in prevalence of ICAD >50% was steeper for Māori and Pacific Peoples p = 0.0014 (European vs Maori and Pacific).
Conclusion
Prevalence of ICAD with incident ischaemic stroke was lower than in other reports,without ethnic variation. The association between age and ethnicity in relation to severity of ICAD merits further exploration.