Favorable Venous Outflow Profiles Correlate With Favorable Tissue-Level Collaterals and Clinical Outcome

Abstract

Background and Purpose: Patients with acute ischemic stroke due to large vessel occlusion and favorable tissue-level collaterals (TLCs) likely have robust cortical venous outflow (VO). We hypothesized that favorable VO predicts robust TLC and good clinical outcomes. Methods: Multicenter retrospective cohort study of consecutive acute ischemic stroke due to large vessel occlusion patients who underwent thrombectomy triage. Included patients had interpretable prethrombectomy computed tomography, computed tomography angiography, and cerebral perfusion imaging. TLCs were measured on cerebral perfusion studies using the hypoperfusion intensity ratio (volume ratio of brain tissue with [Tmax >10 s/Tmax >6 s]). VO was determined by opacification of the vein of Labbé, sphenoparietal sinus, and superficial middle cerebral vein on computed tomography angiography as 0, not visible; 1, moderate opacification; and 2, full. Clinical and demographic data were determined from the electronic medical record. Using multivariable regression analyses, we determined the association between VO and (1) favorable TLC status (defined as hypoperfusion intensity ratio ≤0.4) and (2) good functional outcome (modified Rankin Scale score, 0–2). Results: Six hundred forty-nine patients met inclusion criteria. Patients with favorable VO were younger (median age, 72 [interquartile range (IQR), 62–80] versus 77 [IQR, 66–84] years), had a lower baseline National Institutes of Health Stroke Scale (median, 12 [IQR, 7–17] versus 19 [IQR, 13–20]), and had a higher Alberta Stroke Program Early Computed Tomography Score (median, 9 [IQR, 7–10] versus 7 [IQR, 6–9]). Favorable VO strongly predicted favorable TLC (odds ratio, 4.5 [95% CI, 3.1–6.5]; P <0.001) in an adjusted regression analysis. Favorable VO also predicted good clinical outcome (odds ratio, 10 [95% CI, 6.2–16.0]; P <0.001), while controlling for favorable TLC, age, glucose, baseline National Institutes of Health Stroke Scale, and good vessel reperfusion status. Conclusions: In this selective retrospective cohort study of acute ischemic stroke due to large vessel occlusion patients undergoing thrombectomy triage, favorable VO profiles correlated with favorable TLC and were associated with good functional outcomes after treatment. Future prospective studies should independently validate our findings.

Is infarct core growth linear? Infarct volume estimation by computed tomography perfusion imaging

“…None of the examined demographic or clinical parameters were associated with nonlinear growth of infarct core, but it is likely that the collaterals have an important role. 7,8,[13][14][15]24 Our study suggests that the linear model of infarct core growth is too simplistic, decisions on recanalization should therefore be based more on individual status of brain perfusion rather than on time elapsed from symptom onset particularly in the early time window after stroke. 7,10 Collateral flow has important role in ischemic core growth.…”

Early Edema Within the Ischemic Core Is Time-Dependent and Associated With Functional Outcomes of Acute Ischemic Stroke Patients

“…Besides the infarct time, other factors may relate to early edema. The collateral status reflects the cerebral microperfusion status of patients with acute ischemic stroke, which is linked to edema formation and core growth ( 27 ). A previous study showed an association between favorable venous flow profiles and ischemic lesion NWU growth ( 28 ).…”

“…We did not find a statistically significant relation between modified ASITN/SIR score on dynamic CT and NWU, but there was the tendency of different NWU between good collateral and poor collateral groups. More included cases and appropriate assessments on tissue-level collaterals together with venous outflow ( 27 ) may strongly approve the relation between NWU and collateral status of patients with ischemic stroke. Another factor is ischemic core volume, which is recognized as the most essential variable influencing prognosis.…”

Imaging in Acute Anterior Circulation Ischemic Stroke: Current and Future

“…Brain perfusion is not only determined by the arterial inflow but also by downstream resistance due to tissue pressure or capillary and venous characteristics. Faizy et al [ 36 ] showed that favorable venous outflow profiles, which were assessed by counting veins on CTA, correlate with favorable tissue-level collaterals and clinical outcomes. However, venous outflow profiles based on CTA have the similar limitation of underestimating the collaterals with a longer transit time or slow hemodynamics like single-phase CTA.…”