ABSTRACT BODY:
Objective(s): Neurocognitive deficits (NCDs) have been found to occur frequently following cardiac surgery. Although NCDs have received significant attention in the medical literature and public media, the true clinical impact of these deficits on patient outcomes and quality of life is not well defined.

Methods: Neuropsychometric testing was performed on 696 patients undergoing coronary artery bypass surgery using a battery of 14 tests divided into 4 domains assessing memory, attention, speed, and psychomotor function. Neurocognitive assessments were performed preoperatively (100% complete), at hospital discharge (99% complete), and at 3 months postoperatively (94% complete). Neurocognitive deficits were defined as a drop in scores by 1 standard deviation in ‰¥ 1 domain. Quality of life was assessed using Short Form 36 and clinical outcomes were recorded. Mean age was 65 + 8 years and 88% were male.

Results: There was no in-hospital mortality and 99% survived at 3 months. NCDs were identified in 265 (38%) patients at discharge and in 132 (19%) at 3 months. Predictors of NCD at discharge were elevated preoperative creatinine (p = 0.04), increased cardiopulmonary bypass time (p = 0.005), and diabetes (p = 0.003). Intensive care unit stay (1.6 + 2.2 vs. 1.3 + 1.3 days, p = 0.05) and hospital stay (6.9 + 4.3 vs. 6.2 + 2.9 days, p = 0.01) were slightly longer in NCD patients. At 3 months, patients experienced improvements in both physical (34 + 2% increase vs. baseline) and mental (10 + 1% increase vs. baseline) components of quality of life, independent of the occurrence of NCDs (p > 0.5). Independent predictors of quality of life improvement included younger age, severe preoperative symptoms, normal left ventricular function, and absence of post-operative wound infection, but not NCDs (Table 1).

Conclusions: Neurocognitive deficits can be frequently detected on comprehensive neuropsychometric testing following cardiac surgery. However, they are not associated with any clinically important differences in patient outcome or in quality of life after surgery.

Table 1: Predictors of Improved Quality of Life Following Cardiac Surgery