Background
Computed tomography(CT) scans of the head without contrast are routinely obtained to evaluate neurologic deficits after cardiac surgery(CS), but their utility is unknown. We evaluated our experience with this imaging modality to determine its value.
Methods
We retrospectively identified CS patients with postoperative neurologic deficits occurring during the first week after surgery between January 2000 and December 2012. Stroke was defined by neurologist’s determination, while a non-focal deficit(NFD) was defined by the presence of seizure, delirium, or cognitive impairment. We defined early non-contrast head CT as occurring within 7 days of surgery. Outcomes included positive findings on CT, in-hospital mortality and length of stay(LOS). Multivariate logistic regression identified predictors of positive findings on head CT.
Results
Within the population of 11,070 postoperative patients, 451 had early non-contrast head CT scans (4%). 202(44.7%) were associated with stroke and 249(55.2%) with NFD. Among stroke patients, 40/202(20%) showed acute infarction, 17/202(8%) showed sub-acute infarction, and 5/202(2%) showed hemorrhage. Among NFD patients, 1/248(0.4%) showed acute infarction, 4/248(1.6%) sub-acute infarction, and 1/248(0.4%) hemorrhage. There was no difference in in-hospital mortality(S:42/201(21%) versus NFD:41/248(16%), p=0.2) or LOS (S:24d versus NFD:22d, p=0.5). On multivariable logistic regression, only focal deficits and aortic procedures predicted a positive finding on CT scan.
Conclusions
To our knowledge, this is the only modern study to review the utility of early postoperative non-contrast head CT in CS patients. With focal neurologic deficits, this imaging modality was positive for approximately one third of patients, but rarely positive for NFD. Its use in this setting has limited utility.