Association of Brain Arterial Elongation With Risk of Stroke and Death in Stroke-Free Individuals: Results From NOMAS

Abstract

Background: Brain arterial dilation and elongation characterize dolichoectasia, an arteriopathy associated with risk of stroke and death. We aim to determine whether brain arterial elongation increases the risk of stroke and death independent of brain arterial diameters. Methods: We analyzed 1210 stroke-free participants (mean age 71±9 years, 41% men, 65% Hispanic) with available time-of-flight magnetic resonance angiogram from the Northern Manhattan Study, a population-based cohort study across a multiethnic urban community. We obtained baseline middle cerebral artery M1-segment (MCA-M1) and basilar artery (BA) mean lengths and diameters using a semi-automated software. Cox proportional hazards models adjusted for brain arterial diameters and potential confounders yielded adjusted hazards ratios with 95% CIs for the primary outcomes of incident stroke and all-cause mortality, as well as secondary outcomes including noncardioembolic stroke, vascular death, and any vascular event. Results: Neither MCA-M1 nor BA lengths correlated with incident stroke or all-cause mortality. Both MCA-M1 and BA larger diameters correlated with all-cause mortality (MCA-M1 aHR, 1.52 [95% CI, 1.03–2.23], BA aHR, 1.28 [95% CI, 1.02–1.61]), as well as larger MCA-M1 diameters with vascular death (aHR, 1.84 [95% CI, 1.02–3.31]). Larger MCA-M1 and BA diameters did not correlate with incident stroke. However, larger BA diameters were associated with posterior circulation noncardioembolic stroke (aHR, 2.93 [95% CI, 1.07–8.04]). There were no statistical interactions between brain arterial lengths and diameters in relation to study outcomes. Conclusions: In a multiethnic cohort of stroke-free adults, brain arterial elongation did not correlate with risk of stroke or death, nor influenced the significant association between brain arterial dilation and vascular risk.

Association of brain arterial diameters with demographic and anatomical factors in a multi-national pooled analysis of cohort studies

“…Larger brain arterial diameters are a risk marker for stroke, 3,5 vascular events, 1,3,5 cognitive impairment, 28 and mortality, 1,4,5 whereas the extreme phenotype of brain arterial dilation (dolichoectasia) is recognized as a direct etiology for cerebrovascular disorders such as ischemic stroke, intracerebral hemorrhage, and brain tissue compression syndromes. 29 Understanding the association of demographic and anatomical characteristics with brain arterial diameters is critical to discriminate expected brain arterial diameters variability within the normal spectrum from the abnormal widening of brain arteries in response to pathological processes.…”

“…A prespecified and harmonized imaging analysis protocol was applied to obtain cross-sectional arterial diameters in 13 intracranial arterial segments at the base of the skull using commercially available software (LAVA, Leiden University Medical Center, The Netherlands, build date October 19th, 2018) previously validated by our group and others (Figure 2). 5,13,26 For each individual, we calculated the average diameter in millimeters (mm) for the ascending portion of the cavernous internal carotid arteries (ICA), the intracranial portion of the vertebral arteries (V4 segment), and the basilar artery (BA). For the middle cerebral arteries (MCA), the anterior cerebral arteries (ACA), and the posterior cerebral arteries (PCA), we only used the most proximal average diameter (first 1 mm) given the highly variable length of these arterial segments.…”

“…2 Moreover, larger brain arterial diameters-the extreme phenotype of which is known as dolichoectasia-are an increasingly recognized marker of vascular-related morbidity and mortality. 1,[3][4][5] In contrast to intracranial atherosclerosis, where standardized methods exist to establish arterial stenosis and its severity, 6 there is no unified criteria to determine pathological brain arterial dilation. Previous proposed definitions for abnormal brain dilation (or dolichoectasia) were based on diameters distribution from relatively small study populations, [7][8][9] focused on individuals with stroke, 10,11 or assessed arterial diameters only in the posterior circulation.…”