Purpose/aim of the study: Cerebrovascular reactivity (CVR) reflects the vasodilatory reserve of cerebral resistance vessels, which is an important marker for assessing cerebrovascular disease. The present study is to investigate whether CVR impairment increases adverse long-term outcome risk of patients with ≥ 50% symptomatic unilateral middle cerebral artery (MCA) stenosis (ischemic stroke (IS) or transient ischemic attack (TIA)).
Material and methods: Digital subtraction angiography (DSA) was used to assess the degree of stenosis, and perfusion CT and 5% CO2 inhalation were adopted to evaluate CVR. Patients with ≥ 50% symptomatic unilateral MCA stenosis were assigned to non-CVR impairment group and CVR impairment group according to CVR status. The long-term follow-up endpoint was composite of any IS ( in the territory of the studied MCA) or death within 12 months.
Results: Seventy-three patients with ≥ 50% symptomatic unilateral MCA stenosis, involving 31 non-CVR impairment cases and 42 CVR impairment cases, were included in the present study. Finally, IS occurred in six CVR impairment patients, and no endpoint happened in the non-CVR impairment group. Therefore, the annual rate of IS was 14.29% in the CVR impairment group and 0% in the non-CVR impairment group (P = 0.035). Besides, further Kaplan-Meier analysis found CVR impairment was closely associated with the IS risk (Kaplan-Meier Log-rank 4.719, P = 0.030).
Conclusions: Our results showed that for patients with ≥ 50% symptomatic unilateral MCA stenosis, there was significant difference between non-CVR impairment cases and CVR impairment cases in the annual rate of IS. It suggests that CVR impairment increases the risk of adverse long-term outcomes.
Keywords: CO2 inhalation; Middle cerebral artery; cerebrovascular reactivity; ischemic stroke; perfusion computed tomography.