Leukoaraiosis and collateral blood flow in stroke patients with anterior circulation large vessel occlusion

Abstract

BackgroundLeukoaraiosis and collateral blood flow are processes that involve small vessels, the former related to flow within the deep perforating arterioles and the latter involving the small, cortical pial-pial connections, both of which are independently used to predict cerebrovascular events and treatment outcomes. The aim of this study was to investigate their relationship to each other.MethodsWe retrospectively reviewed patients who underwent mechanical thrombectomy for stroke with pre-procedural CT imaging within 24 hours of the onset of symptoms. Leukoaraiosis was graded by the total Fazekas score on non-contrast CT, periventricular white matter (PVWM) and deep white matter (DWM) scores, both ranging from 0 to 3. Collateral cerebral blood flow was measured by the American Society of Interventional and Therapeutic Radiology/Society of Interventional Radiology (ASITN/SIR) collateral scale.Results178 patients were included with a mean age of 67.6±14.8 years. We found an inverse relationship between total Fazekas score and collateral flow (p<0.0001). Among patients with good collaterals, 75.1% had total Fazekas scores of 0–2, compared with 36.6% of patients with moderate collaterals and 32.7% of patients with poor collaterals with total Fazekas scores of 0–2. Mean Fazekas scores were 1.6±1.5, 3.1±1.5 and 3.4±1.6 for good, moderate and poor collaterals, respectively (p<0.0001). On multivariate analysis, total Fazekas score was the only variable independently associated with collateral status (p<0.0001).ConclusionsIncreasing severity of leukoaraiosis is associated with poor collateral grade among ischemic stroke patients with anterior circulation large vessel occlusion. These findings suggest that leukoaraiosis may be a marker for global cerebrovascular dysfunction.

Associations between white matter hyperintensity burden, cerebral blood flow and transit time in small vessel disease: an updated meta-analysis

“…29,30 Seven of the 27 new cross-sectional studies reported only the results of association analyses, and did not provide quantitative data for CBF or WMH measurements. Patient groups in these studies included patients with acute stroke, 12,31 MCI, 32 vascular depression 33 , individuals at varying risk of cerebrovascular disease 34 and older individuals with WMH. 17,35 The three newly identified longitudinal studies (n=440) investigated baseline CBF and WMH progression in older individuals with WMH (Table 1) over follow-up periods ranging from two 36 to five 37 years.…”

“…While 2 studies investigated associations between baseline WMH volume and change in either subregional 15 or global 37 CBF, one study considered associations between change in WMH volume and change in cortical grey matter CBF. 36 Fifteen studies used ASL 6-8, 10, 14, 15, 19, 20, 25, 27, 30, 32, 34-36 , 3 used CT perfusion 18,28,29 , 2 used dynamic susceptibility contrast (DSC) MRI 9,37 , one study each used SPECT 21 , phase contrast MRI 22 , CT angiography/digital subtraction angiography, 31 PET, 23 and a combination of CT and DSC MRI 12 . Five studies used transcranial Doppler ultrasound 16,17,24,26,33 .…”

“…6,18,27,28 Only 5 of these 11 studies adjusted for key vascular risk factors, including hypertension and smoking. 12,17,31,33,34 Cross-sectional analysis of associations between global or regional CBF and WMH. Four of the new studies analysed associations between global or regional CBF and WMH burden ( Table 2).…”

“…18 Worse WMH were associated with poorer cerebral collateral circulation, defined as cortical CBF at the outer surface of the brain, in one study which investigated patients with acute stroke (n=178). 31 Two of the new studies showed that lower mean blood flow velocity (MBFv) in the internal carotid artery and middle cerebral artery were associated with worse WMH burden in patients with ischaemic leukoaraiosis (n=96) 17 and vascular depression (n=76) 33 (Table 2). assessed SVD burden on CT or MRI, using an SVD score, 12 and four transit time metrics (MTT, time to maximum flow, time to peak and arrival time fitted) derived from perfusion CT or DSC MRI, in the asymptomatic cerebral hemisphere of patients with acute ischaemic stroke (n=115).…”

“…The direction of effect in the remaining studies did not change: lower blood flow velocity17,33 and prolonged perfusion CT/DSC transit time metrics12 remained associated with WMH, as well as lower CBF within WMH compared to NAWM 34. Only one cross-sectional study investigated WMH in association with global or regional CBF while adjusting for key vascular risk factors, showing worse WMH was associated with poorer collateral blood flow 31. Longitudinal analyses of WMH and CBFThe largest of the three new longitudinal studies (Nylander et al 2017)37 in a cohort of 406 randomly selected 75 year old participants at baseline and 252 at follow-up, found no significant association between baseline CBF with WMH progression at a five year follow-up when adjusting for baseline WMH and sex(Table 4).…”