Introduction: Normal perfusion pressure breakthrough phenomenon (NPPB) is a major life-threatening complication that restricts the treatment of high grade intracranial arteriovenous malformations. A rat model mimicking NPPB phenomenon has been developed in order to evaluate any therapy that may prevent or treat such an important complication.
Methods: Twenty Wistar male rats were randomly assigned to a study or a control group. Study animals underwent an end-to-side left external jugular vein-common carotid artery anastomosis and ligation of bilateral external carotid arteries. Control animals underwent ligation of bilateral external carotid arteries. Sixty days after the procedure, all animals were sacrificed. Hemodynamic parameters (mean arterial pressure (MAP), intracranial pressure (ICP) and cerebral perfusion pressure (CPP) recorded on days 0, 7 and 60), blood-brain barrier (BBB) permeability (measured by fluorescein extravasation) and histological features were compared between both groups.
Results: A significant decrease in MAP and CPP was confirmed in the study group when compared with the control group. An increase in ICP was also observed, but it was only statistically significant on day 7. A significant decrease in MAP and CPP was also evidenced in the study group when comparing preoperative values with those recorded on days 0 (postoperative), 7 and 60. Fluorescein extravasation was also evidenced in study animals as a signal of BBB disruption. Histological analysis demonstrated edema and multifocal hemorrhage with angioarchitectural and parenchymal changes.
Conclusions: The results evidence that the model mimics a vascular steal state with chronic cerebral hypoperfusion, disruption of the BBB and histological changes, which may be comparable to NPPB phenomenon disorders.
Patient Care: The model mimics NPPB phenomenon events and it may be therefore useful in subsequent research on preventive or therapeutic measures with the aim of controlling this life-threatening complication that restricts the definitive treatment of high grade intracranial arteriovenous malformations.
Learning Objectives: Experimental research is a helpful tool in the knowledge and consolidation of certain concepts regarding NPPB phenomenon. Besides that, it is essential when clinical research cannot be achieved in a clinical-autopsy field.