Table II.
HITS and Cognitive Function after Carotid Endarterectomy
| Author & Year | Study Type | Surgical Procedure | n | Cognitive Testing Definition of Decline | Testing Time | Cognition Findings in Relation to TCD |
|---|---|---|---|---|---|---|
| Bossema, 2005 [65] | Prospective | CEA | 58 | 8 NP Tests >1SD decline from preop |
Preop; Postop 3 months |
No association between HITS and cognitive decline 3 months postop |
| Lloyd, 2004 [66] | Randomized Prospective |
CEA | 100 | NP Battery of 7 cognitive domains |
Preop; 6 months Post-op |
Patients subjected to >10 HITS during carotid dissection had decline in at least two tests of cognition (p< 0.05; relative risk = 1.125) |
| Fearn, 2003[67] | Prospective Controlled |
CEA | 159 | Cognitive Drug Research Battery (4 tests) |
Preop; Postop 5 days and 2 months |
Overall, no association with HITS Patients with >10 HITS prior to dissection (n=6) tended to be slower in memory |
| Controls | 20 | |||||
| Crawley, 2000[24] | Prospective Matched |
CEA | 26 | 10 NP Tests ≥1 SD decline in ≥2 tests |
Preop; Postop 6 weeks & 6 months |
More HITS in PTCA No correlation between HITS and NP score |
| Carotid PTCA |
20 | |||||
| Gaunt, 1994 [16] | Randomized Prospective |
CEA | 100 | 30-point NP Assessment | Pre-op; 5–7 days Post-op |
>10 particulate embolic events detected by TCD correlated to post-operative cognitive decline (p<0.05) |
CEA-Carotid endarterectomy; HITS – high intensity transient signals; NP-neuropsychological; On-Pump- utilizing the cardio-pulmonary bypass machine/pump ; Off-pump – surgery not requiring use of the cardio-pulmonary bypass machine/pump; Preop – preoperative; Postop- postoperative; PTCA – angioplasty; SD – standard deviation