Brain atrophy and white-matter hyperintensities are not significantly associated with incidence and severity of postoperative delirium in older persons without dementia

Abstract

Postoperative delirium is a common complication in older people, and is associated with increased mortality, morbidity, institutionalization and caregiver burden. Although delirium is an acute confusional state characterized by global impairments in attention and cognition, it has been implicated in permanent cognitive impairment and dementia. The pathogenesis of delirium, as well as the mechanisms leading to these disabling consequences, remains unclear. The present study is the first to address the potential predisposing role of brain morphological changes towards postoperative delirium in a large prospective cohort of patients undergoing elective surgery using state-of-the-art magnetic resonance imaging (MRI) techniques conducted before admission. We investigated the association of MRI-derived quantitative measures of white matter damage, global brain and hippocampal volume with the incidence and severity of delirium. Pre-surgical white matter hyperintensities (WMH), whole brain and hippocampal volume were measured in 146 consecutively enrolled subjects, ≥70 years old, without dementia who were undergoing elective surgery. These three pre-surgical MRI indices were tested as predictors of incidence and severity of subsequent delirium. Out of 146 subjects, 32 (22%) developed delirium. We found no statistically significant differences in WMH, whole brain or hippocampal volume between subjects with and without delirium. Both unadjusted and adjusted (age, gender, vascular comorbidity, general cognitive performance) regression analyses demonstrated no statistically significant association between any of the MRI measures with respect to delirium incidence or severity. In persons without dementia, preexisting cerebral white matter hyperintensities, general and hippocampal atrophy may not predispose to postoperative delirium or worsen its severity.

Association of postoperative delirium with markers of neurodegeneration and brain amyloidosis: a pilot study

“…We found comparable WMHs in POD-positive and POD-negative patients, in line with previous findings on a large sample of nondemented patients older than 70 years, showing that WMHs volumes were not associated with POD incidence after elective surgery (Cavallari et al, 2015).…”

“…Previous studies found no association between hippocampal volumes and POD (Cavallari et al, 2015), while the fusiform gyrus and the middle temporal gyrus showed moderate accuracy in predicting delirium (Shioiri et al, 2015). These latter findings are in line with our results describing a significant GM reduction in the right middle temporal gyrus.…”

Patients prone for postoperative delirium

“…ApoE4, a marker of Alzheimer's disease, was no risk factor in surgical patients [31,32]. One study group found brain atrophy not to be associated with incidence of POD [33], whereas others identified decreased grey matter volume or cerebral atrophy contributing to POD [34,35].…”

Alzheimer's-related cortical atrophy is associated with postoperative delirium severity in persons without dementia

“…In individuals without dementia, some studies have reported an association between cerebrospinal fluid (CSF) or plasma levels of Aβ and tau and delirium (Idland et al, 2016; van den Boogaard et al, 2011; Xie et al, 2014) while others have not (Witlox et al, 2011). Similarly, some magnetic resonance imaging (MRI) studies of regional brain volume and delirium have identified an association (Gunther et al, 2012; Shioiri et al, 2016) while others have not (Cavallari et al, 2015; Root et al, 2013). To date, brain volume studies in delirium research have used mostly exploratory methods rather than a priori -defined region-of-interest measures of brain regions vulnerable to AD pathology, making inferences about the connection to AD difficult or impossible.…”