Neurosurgery Unit, Department of Clinical Neurosciences, University of Cambridge, Cambridge, UK.
Biomedical Engineering Department, California State University, Long Beach, CA, USA.
Acta Neurochir Suppl. 2021;131:349-353. doi: 10.1007/978-3-030-59436-7_67.
We previously examined the relationship between global autoregulation pressure reactivity index (PRx), mean arterial blood pressure (ABP), Resistance to cerebral spinal fluid (CSF) outflow (Rout) and their possible effects on outcome after surgery on 83 shunted patients. In this study, we aimed to quantify the relationship between all parameters that influence Rout, their interaction with the cerebral vasculature, and their role in shunt prognostication.
From 423 patients having undergone infusion tests for possible NPH, we selected those with monitored ABP and calculated its mean and PRx. After shunting, 6 months patients' outcome was marked using a simple scale (improvement, temporary improvement, and no improvement). We explored the relationship between age, different CSF dynamics variables, and vascular parameters using multivariable models.
Rout had a weaker predictive value than ABP (Fisher Discrimination Ratio of 0.02 versus 0.42). ABP > 98 was an independent predictor of shunt outcome with odd ratio 6.4, 95% CI: 1.8-23.4 and p-value = 0.004. There was a strong and significant relationship between the interaction of age, PRx, ABP, and Rout (R = 0.53 with p = 7.28 × 10). Using our linear model, we achieved an AUC 86.4% (95% CI: 80.5-92.3%) in detecting shunt respondents. The overall sensitivity was 94%, specificity 75%, positive predictive value (PPV) of 54%, and negative predictive value of 97%.
In patients with low Rout and high cerebrovascular burden, as described by high ABP and disturbed global autoregulation, response to shunting is less likely. The low PPV of high resistance, preserved autoregulation and absence of hypertension could merit further exploration.
我们之前研究了 83 例分流术后患者的全局自动调节压力反应指数（PRx）、平均动脉血压（ABP）、脑脊髓液（CSF）流出阻力（Rout）之间的关系及其对手术结果的可能影响。在这项研究中，我们旨在量化影响 Rout 的所有参数之间的关系，它们与脑血管的相互作用，以及它们在分流术预后中的作用。
我们从 423 例接受过可能的 NPH 输注试验的患者中选择了那些有监测 ABP 的患者，并计算了其平均值和 PRx。分流术后 6 个月，采用简单量表（改善、暂时改善和无改善）标记患者的预后。我们使用多变量模型探讨了年龄、不同 CSF 动力学变量和血管参数之间的关系。
与 ABP（Fisher 判别比 0.02 对 0.42）相比，Rout 的预测价值较弱。ABP > 98 是分流术结果的独立预测因子，优势比为 6.4，95%CI：1.8-23.4，p 值 = 0.004。年龄、PRx、ABP 和 Rout 之间的相互作用具有很强的显著关系（R = 0.53，p = 7.28 × 10）。使用我们的线性模型，我们在检测分流术应答者方面达到了 86.4%的 AUC（95%CI：80.5-92.3%）。总的敏感性为 94%，特异性为 75%，阳性预测值（PPV）为 54%，阴性预测值为 97%。
在 Rout 低且脑血管负担高的患者中，如 ABP 升高和全局自动调节紊乱所述，分流术反应的可能性较低。高阻力、保留自动调节和无高血压的低 PPV可能值得进一步探索。
