Eriksen Niclas Lynge, Poulsen Frantz Rom, Andersen Mikkel Schou, Nortvig Mathias Just
Department of Neurosurgery, Odense University Hospital, Odense, Denmark.
Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.
Acta Neurochir (Wien). 2025 Jan 25;167(1):24. doi: 10.1007/s00701-025-06437-3.
Intracranial pressure (ICP) monitoring is in most studies considered essential in avoiding secondary brain injury in patients with intracranial pathologies. Invasive monitoring of ICP is accurate but is unavailable in many clinical and prehospital settings. Non-invasive modalities have historically been difficult to implement clinically. The retinal arteriovenous ratio (A/V ratio) has shown promise through its relationship with ICP. This study aimed to further elucidate the relationship between ICP, A/V ratio and the intraocular pressure (IOP) measured with non-invasive fundoscopy in a porcine model.
We achieved controlled values of ICP ranging from normal (5-15 mmHg) to elevated (> 20 mmHg) within the same animal subject. Six pigs were included. ICP and IOP was measured using an intraparenchymal pressure monitor and a tonometer, respectively. Fundoscopy was performed at baseline and at predefined ICP values.
Mixed-effects linear regression revealed a significant inverse correlation between A/V ratio and ICP ≥ 20 mmHg (slope coefficient - 0.0026734 [95%-CI: -0.0039347 - (-0.0014121)], p < 0.001). For ICP < 20 mmHg there was no change in A/V ratio (p = 0.987). Similar results were seen for ICP > IOP with a mean IOP of 10 mmHg. A Wald test showed no significant difference between ICP > IOP and ICP ≥ 20 mmHg. ROC curve analysis revealed an AUC of 0.64 for ICP ≥ 20 mmHg and 0.71 for ICP > IOP.
The results support the hypothesis that an increase in ICP was associated with a decrease in A/V ratio. Although a slightly better fit, the model of ICP > IOP was deemed less clinically relevant than ICP ≥ 20 mmHg because of the subjects' IOP. Further research integrating multifactorial models and machine learning is needed to enhance the diagnostic accuracy of A/V ratio via fundoscopy, enabling it to serve as a cost-effective screening tool.
在大多数研究中，颅内压（ICP）监测被认为是避免颅内病变患者发生继发性脑损伤的关键。有创ICP监测准确，但在许多临床和院前环境中无法使用。历史上，无创监测方法在临床上难以实施。视网膜动静脉比值（A/V比值）通过其与ICP的关系显示出应用前景。本研究旨在进一步阐明猪模型中ICP、A/V比值与通过无创眼底镜测量的眼压（IOP）之间的关系。
在同一动物个体内，我们将ICP控制在正常范围（5 - 15 mmHg）至升高范围（> 20 mmHg）。纳入6头猪。分别使用脑实质内压力监测器和眼压计测量ICP和IOP。在基线和预定义的ICP值时进行眼底镜检查。
混合效应线性回归显示，当ICP≥20 mmHg时，A/V比值与之呈显著负相关（斜率系数 -0.0026734 [95%置信区间：-0.0039347 - (-0.0014121)]，p < 0.001）。当ICP < 20 mmHg时，A/V比值无变化（p = 0.987）。对于平均IOP为10 mmHg且ICP > IOP的情况，也观察到了类似结果。Wald检验显示ICP > IOP与ICP≥20 mmHg之间无显著差异。ROC曲线分析显示，对于ICP≥20 mmHg，AUC为0.64；对于ICP > IOP，AUC为0.71。
结果支持以下假设，即ICP升高与A/V比值降低相关。尽管拟合度稍好，但由于受试者的IOP，ICP > IOP模型在临床上的相关性低于ICP≥20 mmHg。需要进一步开展整合多因素模型和机器学习的研究，以提高通过眼底镜检查A/V比值的诊断准确性，使其成为一种经济有效的筛查工具。
