Depression In Patients Undergoing Coronary Artery Bypass Graft (CABG) Surgery is Associated with Worse Cognition and Left Middle Cerebral Artery Stenosis

Abstract: Background/Significance: Pre-CABG depression is common and associated with post-CABG morbidity and mortality (Burg 2003; Stenman 2016). Given the advanced age and high prevalence of cerebrovascular risk factors among CABG patients, pre-CABG depression might be consistent with “vascular depression hypothesis” which posits “cerebrovascular disease may predispose, precipitate, or perpetuate some geriatric syndromes.” (Alexopoulus 1997) Testing vascular depression hypothesis of pre-CABG depression might elucidate the etiopathogenesis of pre-CABG depression and guide development of prevention and treatment strategy.

Methods: We conducted a cross-sectional analysis of pre-CABG data from the Neuropsychiatric Outcomes After Heart Surgery (NOAHS) study (Oldham 2019), a prospective observational cohort study of patients undergoing CABG at a tertiary academic center. The study sample consisted of 161 of 168 NOAHS participants, who were assessed for Pre-CABG depression by a trained clinician based on Depression Interview and Structured Hamilton (DISH). Of 161, 127 had a complete Transcranial Doppler (TCD) assessment for intracranial stenosis, 155 subjects were assessed based on Clinical Dementia Rating (CDR) Scale, and 97 completed a full battery of neuropsychological tests. Baseline sociodemographic variables, cardiovascular risk factors were compared between the depressed group and non-depressed group using independent t-tests. Binary logistic regression was used to determine significant risk factors (p < 0.05).

Results: Of those who completed DISH assessment, 14 met criteria for pre-CABG depression (minor or major). Those with depression were more likely to be younger (61.1±10.3 vs. 66.6±9.1; p=.035) and female (50.0% vs. 22.4%; p=.045). Greater than 50% of stenosis in the left MCA (n=20) was associated with higher odds of pre-CABG depression even when adjusted for age and gender (OR=4.5, 95% CI: 1.0, 20.3, p=.049). Pre-CABG depression was also associated with lower T-score in Letter Fluency Test (OR=0.90, 95% CI: 0.821, 0.995, p=0.038). Lower Trail Making Test A and B percentile was associated with Pre-CABG depression on univariate analysis but lost significance after adjustment for age and gender.

Discussion: Vascular depression is associated with older age of onset, cognitive impairment, vascular risk factors, and higher cardiac illness burden (Aizenstein 2016) including need for CABG. Consistent with these clinical features, the pre-CABG depressed group in our analysis had higher odds of left MCA stenosis and worse performance in verbal ability and executive function.

Conclusion/Implications: Our findings indicate that pre-CABG depression shares clinical characteristics with vascular depression. Adequately powered studies are required to confirm the findings of this study and their implications on post-surgical outcomes.

References
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Burg et al. 2003. Psychosomatic Medicine. Doi: 10.1097/01.PSY.0000038940.33335.09
Oldham et al. 2019. Am J Geriatric Psychiatry. Doi:10.1016/j.jagp.2018.12.025
Stenman et al. 2016. Int J Cardiology. Doi:10.1016/j.ijcard.2016.07.216