Short- and long-term outcomes after aneurysmal subarachnoid hemorrhage

Abstract: Aneurysmal subarachnoid hemorrhage (aSAH) is a sudden and devastating event with significant morbidity and mortality. The development of delayed cerebral ischemia (DCI) is a major contributor to the observed high morbidity. Prompt detection of these injuries remains a considerable challenge. This dissertation explores two approaches: heart rate variability (HRV) analysis and inflammatory biomarker evaluation. As an increasing number of patients survive the acute phase, it is crucial to understand the long-term post-SAH complications and sequelae experienced by patients. HRV data and blood samples for inflammatory biomarkers were collected from patients during the acute phase. Correlations between these parameters and the development of DCI and overall outcome were investigated. Follow-up assessments at 1-, 3-, and 5 years post-hemorrhage were conducted via telephone interviews and self-assessment questionnaires. In study I, altered HRV patterns indicating increased sympathetic activation were observed for the patient cohort, particularly those who developed DCI. However, the predictive value of HRV for DCI onset was limited. Patients who did not survive beyond the first year exhibited reduced HRV compared with survivors. Study II investigated the potential of five inflammatory biomarkers (TNF-α, IL-6, IL-1Ra ICAM-1, and CRP) in peripheral blood to predict DCI. No clear association was found between elevated levels of biomarkers and DCI development. However, patients with unfavorable outcomes had higher biomarker levels during the acute phase. Studies III and IV revealed that cognitive impairments, especially mental fatigue, persisted several years after the initial hemorrhage. Although many patients improved, approximately half continued to experience mental fatigue after 5 years. Further research is needed to refine prediction methods for the development of DCI. Follow-up assessments should extend several years after an aSAH and include broad assessment instruments focusing on cognitive outcomes, particularly mental fatigue.