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Updated: Oct 18, 2026
Optimized System for Cerebral Perfusion Monitoring in the Rat Stroke Model of Intraluminal Middle Cerebral Artery Occlusion
Published on: February 17, 2013
Influence of simultaneous pressor and vasodilatory agents on the evolution of infarct growth in experimental acute
Niloufar Saadat1, Gregory A Christoforidis2, Yong Ik Jeong1
1Radiology, University of Chicago, Chicago, Illinois, USA.
Background:
This study sought to test the hypothesis that simultaneous central blood pressure elevation and potent vasodilation can mitigate pial collateral-dependent infarct growth in acute ischemic stroke.
Methods:
Twenty mongrel canines (20-30 kg) underwent permanent middle cerebral artery occlusion (MCAO). Eight subjects received continuous infusion of norepinephrine (0.1-1.5200 µg/kg/min; titrated to a median of 34 mmHg above baseline mean arterial pressure) and hydralazine (20 mg) starting 30 min following MCAO. Pial collateral recruitment was scored prior to treatment and used to predict infarct volume based on a previously reported parameterization. Serial diffusion magnetic resonance imaging (MRI) acquisitions tracked infarct volumes over a 4-hour time frame. Infarct volumes and infarct volume growth between treatment and control groups were compared with each other and to predicted values. Fluid-attenuated inversion recovery (FLAIR) MRI, susceptibility weighted imaging (SWI), and necropsy findings were included in the evaluation.
Results:
Differences between treatment and control group varied by pial collateral recruitment based on indicator-variable regression effects analysis with interaction confirmed by regression model fit. Benefit in treatment group was only in subjects with poor collaterals which had 35.7% less infarct volume growth (P=0.0008; ANOVA) relative to controls. Measured infarct growth was significantly lower than predicted by the model (linear regression partial F-test, slope P<0.001, intercept=0.003). There was no evidence for cerebral hemorrhage or posterior reversible encephalopathy syndrome.
Conclusion:
Our results indicate that a combination of norepinephrine and hydralazine administered in the acute phase of ischemic stroke mitigates infarct evolution in subjects with poor but not good collateral recruitment.
Insights
This study found that combining norepinephrine and hydralazine reduced infarct growth in acute ischemic stroke, particularly in patients with poor collateral circulation. This treatment shows promise for mitigating stroke progression.
Area of Science:
- Neuroscience
- Cardiovascular Medicine
- Pharmacology
Background:
- Acute ischemic stroke poses a significant threat, with infarct growth influenced by pial collateral circulation.
- Understanding interventions to mitigate infarct expansion is crucial for improving patient outcomes.
Purpose of the Study:
- To test if simultaneous central blood pressure elevation and vasodilation can reduce infarct growth in acute ischemic stroke.
- To investigate the role of pial collateral recruitment in the efficacy of this combined treatment.
Main Methods:
- Twenty canines underwent permanent middle cerebral artery occlusion (MCAO).
- Eight subjects received norepinephrine and hydralazine infusion starting 30 minutes post-MCAO.
- Infarct volumes were tracked via serial diffusion MRI over 4 hours, comparing treatment and control groups.
Main Results:
- The combined treatment significantly reduced infarct volume growth by 35.7% in subjects with poor collateral recruitment compared to controls (P=0.0008).
- No cerebral hemorrhage or posterior reversible encephalopathy syndrome was observed.
- Measured infarct growth was significantly lower than predicted by the model.
Conclusions:
- Simultaneous administration of norepinephrine and hydralazine mitigates infarct evolution in the acute phase of ischemic stroke.
- The therapeutic benefit is specifically observed in patients with poor collateral recruitment, not those with good collaterals.
