Preoperative Altered Spontaneous Brain Activity and Functional Connectivity Were Independent Risk Factors for Delayed Neurocognitive Recovery in Older Adults Undergoing Noncardiac Surgery

Abstract

Objectives. Recently, it has been demonstrated that patients with subtle preexisting cognitive impairment were susceptible to delayed neurocognitive recovery (DNR). This present study investigated whether preoperative alterations in gray matter volume, spontaneous activity, or functional connectivity (FC) were associated with DNR. Methods. This was a nested case-control study of older adults (≥60 years) undergoing noncardiac surgery. All patients received MRI scan at least 1 day prior to surgery. Cognitive function was assessed prior to surgery and at 7-14 days postsurgery. Preoperative gray matter volume, amplitude of low-frequency fluctuation (ALFF), and FC were compared between the DNR patients and non-DNR patients. The independent risk factors associated with DNR were identified using a multivariate logistic regression model. Results. Of the 74 patients who completed assessments, 16/74 (21.6%) had DNR following surgery. There were no differences in gray matter volume between the two groups. However, the DNR patients exhibited higher preoperative ALFF in the bilateral middle cingulate cortex (MCC) and left fusiform gyrus and lower preoperative FC between the bilateral MCC and left calcarine than the non-DNR patients. The multivariate logistic regression analysis showed that higher preoperative spontaneous activity in the bilateral MCC was independently associated with a higher risk of DNR (OR=3.11, 95% CI, 1.30-7.45; P=0.011). A longer education duration (OR=0.57, 95% CI, 0.41-0.81; P=0.001) and higher preoperative FC between the bilateral MCC and left calcarine (OR=0.40, 95% CI, 0.18-0.92; P=0.031) were independently correlated with a lower risk of DNR. Conclusions. Preoperative higher ALFF in the bilateral MCC and lower FC between the bilateral MCC and left calcarine were independently associated with the occurrence of DNR. The present fMRI study identified possible preoperative neuroimaging risk factors for DNR. This trial is registered with Chinese Clinical Trial Registry ChiCTR-DCD-15006096.

Predicting Delayed Neurocognitive Recovery After Non-cardiac Surgery Using Resting-State Brain Network Patterns Combined With Machine Learning

“…The abnormal alterations in FC of calcarine were related to cognitive impairment (Moon and Jeong, 2017). In a previous study, we also found that altered preoperative FC of calcarine was independently associated with the occurrence of DNR (Jiang et al, 2020). The DSST and TMT-A neurocognitive tests were employed to assess the visual-related cognitive function (Joy et al, 2003;Llinàs-Reglà et al, 2017).…”

“…The inclusion and exclusion criteria of our study population have been described previously ( Jiang et al, 2020 ). The inclusion criteria included patients scheduled to undergo non-cardiac surgery, age ≥ 60-years-old, American Society of Anesthesiologists (ASA) classification I-III, and right handedness.…”

“…We used the Z score method recommended by the ISPOCD1 to diagnose DNR for each patient ( Moller et al, 1998 ). This is a standardized method for the identification of postoperative neurocognitive disorders that have been described in a previous study ( Jiang et al, 2020 ). All patients underwent comprehensive neurocognitive tests 1 day before surgery (baseline) and at 7-14 days after the surgery (follow-up).…”

“…We discarded the first five volumes to avoid the potential noise related to the participants’ adaptation to the scanner. The remaining images preprocessing included slice timing, head motion correction, spatial normalization, smoothing (6mm full-width half-maximum Gaussian kernel), low-frequency filtering (0.01-0.08 Hz), linear trend removal, and nuisance covariates regression (motion artifact, white matter signal, and cerebrospinal fluid signal) ( Jiang et al, 2020 ).…”

“…The amplitude of low-frequency fluctuation reflected localized neural activity and was analyzed in our previous study to identify the neuroimaging risk factors for DNR. The previous analyses found that elderly patients with altered preoperative regional neural activity in the bilateral middle cingulate cortex (MCC) were more susceptible to DNR following non-cardiac surgery ( Jiang et al, 2020 ). The estimation of the regional pairwise correlation of blood oxygen level-dependent signals facilitated rs-fMRI to characterize the intrinsic brain network architecture ( Smith et al, 2013 ).…”