The Role of Head Computed Tomography Imaging in the Evaluation of Postoperative Neurologic Deficits in Cardiac Surgery Patients

Abstract

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.

CT Findings of Early Post Operative Neurological Complication of Cardiovascular Surgeries

“…The incidence of neurological deficits following CS varies from 25% to 79% while 6% comprises of FD [6][7][8][9][10][11][12][13][14][15][16][17]. In the study by Beaty et al the incidence of NC in early POP of post CS patient was 6.1% [18]. In our study the incidence of NC in the early POP of CS patients was 6.7% and thus our findings corroborate those of Beaty and colleagues.…”

“…Beaty et al found the incidence of ischemic infarct in FD vs. NFD as 20.1% vs. 0.48% while there was no difference in the incidence of hemorrhage in the two groups [18]. In our study the incidence of ischemic infarct in FD vs. NFD was 73% vs. 27% while the incidence of hemorrhage in the two groups was 20% vs. 60%.…”

“…They also found that the chances of positive CT scan finding was more with FD than with NFD (34% in FD while 2% in NFD) [18]. In our study, the incidence of NFD type of NC in the CS patient was 77% while 33% had FD (stroke) type, i.e.…”

“…In NFD type of NC is primarily due to metabolic cause, so in most of these cases NCCT usually shows no significant findings except in few cases watershed infarcts are seen primarily due to hypo-perfusion. Therefore, in such patients NCCT in immediate POP shows marginal benefits over significant health care cost [18].…”

“…Despite the low sensitivity of NCCT, it is the most important initial modality to diagnose and differentiate the various causes of post-operative NC in CS patients [18]. The Contrast enhanced CT scan helps in localizing the vascular stenosis/occlusion in hyper-acute and acute infarcts and hence helps in determining the benefits of thrombolytic therapy in hyper-acute and acute infarcts [22,23].…”