Transcranial Doppler for Early Prediction of Cognitive Impairment after Aneurysmal Subarachnoid Hemorrhage and the Associated Clinical Biomarkers

Abstract

Background and Aim. Cognitive impairment after aneurysmal subarachnoid hemorrhage (aSAH) stays under investigation. This study is aimed at predicting the cognitive impairment by transcranial Doppler (TCD) and detecting the associated clinical biomarkers of impaired cognition after aSAH after 3 months from the onset. Methods. Prospective study included 40 cases with acute aSAH. Initial evaluation by Glasgow Coma Scale (GCS) and the severity of aSAH was detected by both the clinical Hunt and Hess and radiological Fisher’s grading scales. TCD was done for all patients five times within 10 days measuring the mean flow velocities (MFVs) of cerebral arteries. At the 3-month follow-up, patients were classified into two groups according to Montreal Cognitive Assessment (MoCA) scale: the first group was 31 cases (77.5%) with intact cognitive functions and the other group was 9 cases (22.5%) with impaired cognition. Results. Patients with impaired cognitive functions showed significantly lower mean GCS ( $p=0.03$ ), significantly higher mean Hunt and Hess scale grades ( $p=0.04$ ), significantly higher mean diabetes mellitus (DM) ( $p=0.03$ ), significantly higher mean systolic blood pressure (SBP) and diastolic blood pressure (DBP) ( $p=0.02$ and $p=0.005$ , respectively), and significantly higher MFVs measured within the first 10 days. The patients with cognitive impairment were accompanied by a higher incidence of hydrocephalus ( $p=0.01$ ) and a higher incidence of delayed cerebral ischemia (DCI) ( $p<0.001$ ). Logistic regression analysis detected that $\text{MFV}\ge 86\hspace{0.17em}\hspace{0.17em}\text{cm}/\text{s}$ in the middle cerebral artery (MCA), $\text{MFV}\ge 68\hspace{0.17em}\hspace{0.17em}\text{cm}/\text{s}$ in the anterior cerebral artery (ACA), and $\text{MFV}\ge 45\hspace{0.17em}\hspace{0.17em}\text{cm}/\text{s}$ in the posterior cerebral artery (PCA) were significantly associated with increased risk of cognitive impairment. Conclusion. Cognitive impairment after the 3-month follow-up phase in aSAH patients was 22.5%. Acute hydrocephalus and DCI are highly associated with poor cognitive function in aSAH. Increased MFV is a strong predictor for poor cognitive function in aSAH. This trial is registered with NCT04329208.