Eric J. Heyer, Joanna L. Mergeche and E. Sander Connolly Jr.
Transcranial Doppler (TCD) is frequently used to evaluate peripheral cerebral resistance and cerebral blood flow (CBF) in the middle cerebral artery prior to and during carotid endarterectomy (CEA). Patients with symptomatic carotid artery stenosis may have reduced peripheral cerebral resistance to compensate for inadequate CBF. The authors aim to determine whether symptomatic patients with reduced peripheral cerebral resistance prior to CEA demonstrate increased CBF and cognitive improvement as early as 1 day after CEA.
Fifty-three patients with symptomatic CEA were included in this observational study. All patients underwent neuropsychometric evaluation 24 hours or less preoperatively and 1 day postoperatively. The MCA was evaluated using TCD for CBF mean velocity (MV) and pulsatility index (PI). Pulsatility index ≤ 0.80 was used as a cutoff for reduced peripheral cerebral resistance.
Significantly more patients with baseline PI ≤ 0.80 exhibited cognitive improvement 1 day after CEA than those with PI > 0.80 (35.0% vs 6.1%, p = 0.007). Patients with cognitive improvement had a significantly greater increase in CBF MV than patients without cognitive improvement (13.4 ± 17.1 cm/sec vs 4.3 ± 9.9 cm/sec, p = 0.03). In multivariate regression model, a baseline PI ≤ 0.80 was significantly associated with increased odds of cognitive improvement (OR 7.32 [1.40–59.49], p = 0.02).
Symptomatic CEA patients with reduced peripheral cerebral resistance, measured as PI ≤ 0.80, are likely to have increased CBF and improved cognitive performance as early as 1 day after CEA for symptomatic carotid artery stenosis. Revascularization in this cohort may afford benefits beyond prevention of future stroke. Clinical trial registration no: NCT00597883 (ClinicalTrials.gov).
Eric J. Heyer, Kaitlin A. Mallon, Joanna L. Mergeche, Yaakov Stern and E. Sander Connolly
Neurocognitive performance is used to assess multiple cognitive domains, including motor coordination, before and after carotid endarterectomy (CEA). Although gross motor strength is impaired with ischemia of large cortical areas or of the internal capsule, the authors hypothesize that patients undergoing CEA demonstrate significant motor deficits of hand coordination contralateral to the operative side, which is more clearly manifest in the nondominant hand than in the dominant hand with ischemia of smaller cortical areas.
The neurocognitive performance of 374 patients was evaluated with a battery of neuropsychometric tests. Both asymptomatic and symptomatic patients undergoing CEA were included. The authors evaluated the patients' dominant and nondominant hand performance on the Grooved Pegboard test, a test of hand coordination, to demonstrate their functional laterality. Neurocognitive dysfunction was evaluated as the difference in performance before and after CEA according to group-rate and event-rate analyses. The z scores were generated for all tests using a reference group of patients who were having simple spine surgery. Dominant and nondominant motor coordination functions were evaluated as raw scores and as calculated z scores.
According to event-rate analysis, significantly more patients undergoing CEA of the opposite carotid artery demonstrated nondominant than dominant hand deficits of coordination (41.2% vs 26.4%, respectively, p = 0.02). Similarly, according to group-rate analysis, in patients undergoing CEA of the opposite carotid artery, raw difference scores from the Grooved Pegboard test reflected greater nondominant than dominant hand deficits of coordination (21.0 ± 54.4 vs 9.7 ± 37.0, respectively, p = 0.02).
Patients undergoing CEA of the opposite carotid artery are more likely to demonstrate nondominant than dominant hand deficits of coordination because of greater dexterity in the dominant hand before surgery.
Eric J. Heyer, Christopher P. Kellner, Hani R. Malone, Samuel S. Bruce, Joanna L. Mergeche, Justin T. Ward and E. Sander Connolly Jr.
The role of genetic polymorphisms in the neurological outcome of patients after carotid endarterectomy (CEA) remains unclear. There are single nucleotide polymorphisms (SNPs) that predispose patients to postoperative cognitive dysfunction (CD). We aim to assess the predictability of three complement cascade-related SNPs for CD in patients having CEAs.
In 252 patients undergoing CEA, genotyping was performed for the following polymorphisms: complement component 5 (C5) rs17611, mannose-binding lectin 2 (MBL2) rs7096206, and complement factor H (CFH) rs1061170. Differences among genotypes were analyzed via the chi-square test. Patients were evaluated with a neuropsychometric battery for CD 1 day and 1 month after CEA. A multiple logistic regression model was created. All variables with univariate p < 0.20 were included in the final model.
The C5 genotypes A/G (OR 0.26, 95% CI 0.11–0.60, p = 0.002) and G/G (OR 0.22, 95% CI 0.09–0.52, p < 0.001) were significantly associated with lower odds of exhibiting CD at 1 day after CEA compared with A/A. The CFH genotypes C/T (OR 3.37, 95% CI 1.69–6.92, p < 0.001) and C/C (OR 3.67, 95% CI 1.30–10.06, p = 0.012) were significantly associated with higher odds of exhibiting CD at 1 day after CEA compared with T/T. Statin use was also significantly associated with lower odds of exhibiting CD at 1 day after CEA (OR 0.43, 95% CI 0.22–0.84, p = 0.01). No SNPs were significantly associated with CD at 1 month after CEA.
The presence of a deleterious allele in the C5 and CFH SNPs may predispose patients to exhibit CD after CEA. This finding supports previous data demonstrating that the complement cascade system may play an important role in the development of CD. These findings warrant further investigation.
Eric S. Sussman, Christopher P. Kellner, Joanna L. Mergeche, Samuel S. Bruce, Michael M. McDowell, Eric J. Heyer and E. Sander Connolly
Approximately 25% of patients exhibit cognitive dysfunction 24 hours after carotid endarterectomy (CEA). One of the purported mechanisms of early cognitive dysfunction (eCD) is hypoperfusion due to inadequate collateral circulation during cross-clamping of the carotid artery. The authors assessed whether poor collateral circulation within the circle of Willis, as determined by preoperative CT angiography (CTA) or MR angiography (MRA), could predict eCD.
Patients who underwent CEA after preoperative MRA or CTA imaging and full neuropsychometric evaluation were included in this study (n = 42); 4 patients were excluded due to intraoperative electroencephalographic changes and subsequent shunt placement. Thirty-eight patients were included in the statistical analyses. Patients were stratified according to posterior communicating artery (PCoA) status (radiographic visualization of at least 1 PCoA vs of no PCoAs). Variables with p < 0.20 in univariate analyses were included in a stepwise multivariate logistic regression model to identify predictors of eCD after CEA.
Overall, 23.7% of patients exhibited eCD. In the final multivariate logistic regression model, radiographic absence of both PCoAs was the only independent predictor of eCD (OR 9.64, 95% CI 1.43–64.92, p = 0.02).
The absence of both PCoAs on preoperative radiographic imaging is predictive of eCD after CEA. This finding supports the evidence for an underlying ischemic etiology of eCD. Larger studies are justified to verify the findings of this study. Clinical trial registration no.: NCT00597883 (http://www.clinicaltrials.gov).