Cognitive impairment, delirium common after CABG
Cognitive impairments and delirium are frequent postoperative occurrences in patients who undergo coronary artery bypass grafting (CABG) surgery, according to a new meta-analysis.
A systematic search of PsycINFO, Embase, Cochrane and Medline resulted in 215 studies, corresponding to 91,829 CABG patients. The prevalence of cognitive impairment diagnoses (ie, impairment, delirium and dementia) were assessed according to timing (pre- to post-CABG). Studies with small sample sizes (n<5), without a description of the operationalization and with incomplete reporting of findings, were excluded.
Pooled analysis of 156 studies showed that cognitive impairment was relatively common among patients after CABG. The prevalence rate 4 days after the procedure was 43 percent, which dropped consistently to 39 percent by 1 month, 25 percent by 4 months and 19 percent by 6 months.
In comparison, the prevalence rates of cognitive impairment 1, 1–3, 3–5 and 5 years after the operation were 25 percent, 38 percent, 39 percent and 16 percent, respectively. Preoperative rates were lowest at 19 percent.
Seventy studies focused on delirium and the pooled analysis revealed a prevalence rate of 18 percent up to 1 week after CABG. However, in a sub-analysis of studies that used a standardized instrument for assessment, delirium was observed frequently, at a prevalence rate of 24 percent.
On the other hand, dementia was relatively rare. Analysis of three relevant studies yielded a prevalence rate of 7 percent at 4.9–7.5 years after CABG.