Impact of Pial Collaterals on Infarct Growth Rate in Experimental Acute Ischemic Stroke

Abstract

Background and Purpose This work sought to mathematically model infarct growth and determine if infarct volume growth can be predicted by angiographic assessment of pial collateral recruitment in an experimental Middle Cerebral Artery Occlusion (MCAO) animal model. Materials and Methods Pial collateral recruitment was quantified using DSA, acquired 15 minutes following permanent MCAO in six canines based on a scoring system (Pc) and arterial arrival time (AAT). MRI based infarct volumes were measured 1,1.5,2,3,4 and 24 hours following MCAO and parameterized in terms of growth rate index (G) and final infarct volume (VFinal) as V(t) = VFinal (1−e (−G*t)). Correlations of G and VFinal to Pc and AAT were assessed by linear bivariate analysis. Correlations were used to generate asymptotic models of infarct growth for Pc or AAT values. Pc and AAT based models were assessed by F-test and residual errors. Results Evaluation of pial collateral recruitment at 15 minutes post occlusion were strongly correlated with 24-hour infarct volumes (Pc: r2=0.96, p<0.003; AAT: r2=0.86, p<0.008). Infarct growth, G, had strong and moderate linear relationships to Pc (r2 = 0.89; p<0.0033) and AAT (r2 = 0.69; p<0.0419), respectively. VFinal and G were algebraically replaced by angiographically based collateral assessments to model infarct growth. F-test, demonstrated no statistical advantage to using Pc- over AAT-based predictive models despite lower residual error in the Pc-based mode (p<0.03). Conclusion In an experimental permanent MCAO model, assessment of pial collaterals correlates with infarct growth rate index and has the potential to predict asymptotic infarct volume growth.

EphA4/Tie2 crosstalk regulates leptomeningeal collateral remodeling following ischemic stroke

“…The extent of collateral-mediated reperfusion has a major impact on preserving the penumbra and often dictates stroke outcome (9)(10)(11)(12)(13). Several studies have demonstrated that the outcome after thrombolysis and thrombectomy therapy is highly dependent on patient collateral scoring (14)(15)(16)(17)(18)(19).…”

Absolute quantitative MR perfusion and comparison against stable‐isotope microspheres

“…On day 1, qCBF images were acquired simultaneously with microsphere injection during normocapnia (target PaCO 2 range 30‐40 mmHg using room air) and during hypercapnia (target PaCO 2 range >60 mmHg induced by carbogen gas inhalation (5% CO 2 /95% O 2 )). On day 2 of the study, 4 of the 5 animals underwent permanent endovascular MCAO at the M1 segment while in a normocapnic state. One animal was not imaged on day 2 due to an unanticipated vessel perforation during MCAO, following which the animal was euthanized.…”

“…After completion of the MRI scans, the sheath was removed, and hemostasis was achieved. On day 2, the animal was brought back to the angiography suite where the right MCA was accessed endovascularly using fluoroscopic guidance as previously described . MCAO was verified by selective ipsilateral and contralateral internal carotid and vertebral arteriography (OEC9800, General Electric Healthcare, Chicago, IL).…”

Acute Ischemic Stroke: A Review of Imaging, Patient Selection, and Management in the Endovascular Era. Part I: Initial Management and Imaging

“…They do not take into account the extent of the penumbra that is influenced by other parameters such as collateral status and patient age. 68 Penumbra-based patient selection represents the logical next step in individualized stroke management and may result in better clinical outcomes. 69 Two methods exist of estimating the penumbra: clinical and radiological.…”