Abstract 8931: The Role of Preoperative Hypertension on Neurocognitive Decline After Cardiac Surgery

Abstract

Introduction: Up to 80% of patients experience postoperative neurocognitive decline (pNCD) after cardiac surgery with cardiopulmonary bypass. Objective: We sought to identify the role of pre-op blood pressure (BP) control in pNCD and describe potential contributing mechanisms. Methods: Eligible patients undergoing cardiac surgery with the use of CPB were administered the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) preoperatively and at post-op day 4. We examined 31 patients in this pilot study, of whom 13 experienced pNCD. The highest systolic BP measured within 3 months (maxBP), and the average BP (aBP) taken at clinic visits within 1 year of surgery were used as metrics for BP. T-tests, chi-squared tests, and regression analyses were used. Blood samples were collected 6 hours preoperatively and at postop day 4 to assess cytokine levels (TNFa, C3a, CRP, IL-6) and mRNA expression using Applied Biosystems™ Clariom™ D Pico Assay. Results: Patients who maintained an aBP of ≥130mmHg had greater RBANS deficit than their counterparts (n=19, n=12 respectively; p<0.005). There was also a linear relationship between aBP and RBANS score deficit (F<0.04, adjusted R=11%). These relationships persisted within the younger half patients (n=16, p<0.01) vs. older (n=15, p=0.16). Of patients with stage 2 hypertension or above (≥140mmHg, N=12) 67% experienced pNCD vs. 26% (p=0.02). Within hypertensive patients postoperatively, C3a was upregulated in patients who experienced pNCD (p<0.04). Upon genomic analysis, macrophage markers were uniquely upregulated preoperatively, and genes involved in heme biosynthesis, glutathione synthesis, IL-10 inflammatory attenuation, and oxidative stress attenuation were downregulated postoperatively among patients who maintained an aBP of ≥130mmHg. Conclusions: BP control prior to surgery may play a role in pNCD. Genomic analysis explains a mechanism: upregulated immune response markers preoperatively and a weaker attenuation of oxidative stress and inflammation postoperatively. These effects are more robust among younger patients. The stage of preoperative hypertension may also influence the frequency of pNCD.