Predictors of cognitive decline following coronary artery bypass graft surgery.

BACKGROUND: A significant number of patients develop cognitive impairment that persists for months following coronary artery bypass grafting (CABG) surgery. Our objectives were to identify patient-related risk factors, processes of care, and the occurrence of any perioperative complications associated with cognitive decline. METHODS: Nine hundred thirty-nine patients enrolled in the Processes, Structures, and Outcomes of Care in Cardiac Surgery study undergoing CABG-only surgery at 14 Veterans Administration medical centers between 1992 and 1996 completed a short battery of cognitive tests at baseline and 6-months post-CABG. The composite cognitive score was based on the sum of errors for each individual item in the battery. Multiple linear regression analyses were used to identify independent predictors of the 6-month composite cognitive score. RESULTS: In multivariable analyses, patient characteristics associated with cognitive decline included cerebrovascular disease (p = 0.009), peripheral vascular disease (p = 0.007), history of chronic disabling neurologic illness (p = 0.016), and living alone (p = 0.049), while the number of years of education (p = 0.001) was inversely related to cognitive decline. After adjustment for baseline patient risk factors, the presence of any postoperative complication(s) (p = 0.001) was also associated with cognitive decline while cardiopulmonary bypass time (p = 0.008) was inversely related to cognitive decline. CONCLUSIONS: Patients with noncoronary manifestations of atherosclerosis, chronic disabling neurologic illness, or limited social support are at risk for cognitive decline after CABG surgery. In contrast, more years of education were associated with less cognitive decline. Preoperative assessment of risk factors identified in this study may be useful when counseling patients about the risk for cognitive decline following CABG surgery.

Relationship between processes of care and coronary bypass operative mortality and morbidity.

BACKGROUND: Information is limited regarding the effects of processes of care on cardiac surgical outcomes. Correspondingly, many recommended cardiac surgical processes of care are derived from animal experiments or clinical judgment. This report from the VA Cooperative Study in Health Services, "Processes, Structures, and Outcomes of Cardiac Surgery," focuses on the relationships between 3 process groups (preoperative evaluation, intraoperative care, and supervision by senior physicians) and a composite outcome, perioperative mortality and morbidity. METHODS: Data on 734 risk, process, and structure variables were collected prospectively on 3,988 patients who underwent coronary artery bypass grafting at 14 VA medical centers between 1992 and 1996. Data reduction was accomplished by examining data completeness and variation across sites and surgeon, using previously published data and clinical judgment. We then applied multivariable logistic regression to the 39 remaining processes of care to determine which were related to the composite outcome after adjusting for 17 patient-related risk factors and controlling for intraoperative complications. RESULTS: Our first analysis showed several measures of operative duration, the use of inotropic agents, transesophageal echo, lowest systemic temperature, and hemoconcentration/ultrafiltration, to be powerful predictors of the composite outcome. Because the use of inotropic agents and operative duration may be related to an intermediate outcome (eg, intraoperative complications), we performed a second analysis omitting these processes. The use of intraoperative transesophageal echo and hemoconcentration/ultrafiltration remained significantly associated with an increased risk of an event (odds ratios 1.60 and 1.36, respectively). CONCLUSIONS: Our results viewed in the context of past studies suggest the possibility that inotropic use, TEE, and hemoconcentration/ultrafiltration may have adverse effects on operative outcome. Further evaluation of these processes of care using observational data, as well as randomized trials when feasible, would be of interest.