The purpose of this study was to define outcomes after carotid surgery in octogenarians in the Veterans Affairs health care system. During fiscal years 1991-1994, 9152 patients in DRG 5 underwent extracranial vascular surgery procedures in Veterans Affairs medical centers. Those greater than or equal to 80 years of age constituted 2.1% (n = 195) of such patients. In-hospital mortality rates were 1.03% (92/8957) in those <80 versus 3.08% (6/195) in those greater than or equal to 80 years old (P = 0.018). Of those greater than or equal to 80, 11.8% (23/195) had an ICD-9-CM-coded complication during hospitalization versus 11.2% of those <80 (1004/8957, NS). Surgical complications of the central nervous system (CNS) were present in 0.51% of octogenarians (1/195) and in 0.93% of those younger (83/8957, NS). Myocardial infarction (MI) occurred in 1.0% (2/195) of octogenarians and 0.74% (66/8967) of younger patients (NS). Patient Management Category software was used to define illness severity and resource intensity scale (RIS, a measure of resource utilization). Logistic regression analysis showed that age, illness severity, MI, and surgical complications of the CNS were associated with greater likelihood of mortality after extracranial vascular surgery. When the dichotomous variable "octogenarian status" was substituted for the continuous variable "age,n in this model, there was no significant association of octogenarian status per se with mortality, though the association of illness severity, MI, and CNS complications with mortality persisted. Illness severity was greater for octogenarians (2.03 +/- 1.36) versus those younger (1.84 +/- 1.13, P < 0.05). RIS was 2.57 +/- 0.57 in octogenarians versus 2.47 +/- 0.48 for younger patients (P < 0.015). Length of stay (LOS) was a mean of 3.2 days longer for octogenarians (P < 0.001). The risk of postoperative CNS complications was not higher in octogenarians. Mortality, resource utilization, and length of stay were, however, greater for octogenarians, but so was illness severity. Though mortality rates were greater for octogenarians in DRG 5, illness severity, MI, and postoperative CNS complications had greater impact on mortality after extracranial vascular surgery than octogenarian status per se. (C) 1999 Academic Press.