Cognitive Decline after Delirium in Patients Undergoing Cardiac Surgery

Abstract

What We Already Know about This Topic What This Article Tells Us That Is New Background Delirium is common after cardiac surgery and has been associated with morbidity, mortality, and cognitive decline. However, there are conflicting reports on the magnitude, trajectory, and domains of cognitive change that might be affected. The authors hypothesized that patients with delirium would experience greater cognitive decline at 1 month and 1 yr after cardiac surgery compared to those without delirium. Methods Patients who underwent coronary artery bypass and/or valve surgery with cardiopulmonary bypass were eligible for this cohort study. Delirium was assessed with the Confusion Assessment Method. A neuropsychologic battery was administered before surgery, at 1 month, and at 1 yr later. Linear regression was used to examine the association between delirium and change in composite cognitive Z score from baseline to 1 month (primary outcome). Secondary outcomes were domain-specific changes at 1 month and composite and domain-specific changes at 1 yr. Results The incidence of delirium in 142 patients was 53.5%. Patients with delirium had greater decline in composite cognitive Z score at 1 month (greater decline by −0.29; 95% CI, −0.54 to −0.05; P = 0.020) and in the domains of visuoconstruction and processing speed. From baseline to 1 yr, there was no difference between delirious and nondelirious patients with respect to change in composite cognitive Z score, although greater decline in processing speed persisted among the delirious patients. Conclusions Patients who developed delirium had greater decline in a composite measure of cognition and in visuoconstruction and processing speed domains at 1 month. The differences in cognitive change by delirium were not significant at 1 yr, with the exception of processing speed.

State of the clinical science of perioperative brain health: report from the American Society of Anesthesiologists Brain Health Initiative Summit 2018

“…POD has been associated with decline in cognitive performance in the weeks to months after surgery in several welldone studies. 6,8,40,161,162 One year after surgery, there is often recovery in cognitive function. However, many patients with delirium do not recover to baseline cognitive status, although there is some disagreement between studies.…”

“…However, many patients with delirium do not recover to baseline cognitive status, although there is some disagreement between studies. 6,8,40,161,162 Few prospective studies have examined cognitive outcomes beyond 1 yr, but the largest study of patients undergoing noncardiac surgery found greater cognitive decline beginning at 2 yr after surgery in patients with delirium compared with patients who did not develop delirium. 6 This same group found that patients with the highest delirium severity had the fastest rate of decline, with a doseeresponse relationship between delirium severity and long-term cognitive decline.…”

“…13 Several studies have shown a 'doseeeffect' with greater cognitive decline in patients with higher delirium severity scores. 40,162 Some studies have found that delirium after surgery is associated with incident dementia. 5,163e165 With regard to functional status, there appears to be a greater decline in functional status after surgery amongst patients with POD.…”

Commentary: Does a “less is more” approach reduce delirium in patients undergoing coronary artery bypass grafting?

“…are common in patients who undergo cardiac surgery with cardiopulmonary bypass. 1 There is an ongoing debate regarding the neurocognitive benefits of off-pump coronary artery bypass grafting (OPCAB) relative to on-pump procedures. A proposed theory with the use of OPCAB is the reduced neuroinflammatory response.…”

Current Evidence Regarding Biomarkers Used to Aid Postoperative Delirium Diagnosis in the Field of Cardiac Surgery—Review

“…Data suggested that patients with POD are at higher risk of developing a decline in cognitive performance than those without POD, but this relationship only applies to the first months after surgery and not in the long term [ 25 ]. Nevertheless, POD may be treated as an independent risk factor of postoperative cognitive dysfunction [ 26 ]. In cardiac surgery, the problem of postoperative delirium usually appears within the first five days after the procedure, and many other confounding factors need to be excluded [ 27 , 28 ].…”