Cognition Improves After Endarterectomy for Carotid Stenosis

SAN FRANCISCO – Cognitive function improved for most patients in the year after they underwent endarterectomy for carotid stenosis, according to the results of an ongoing prospective study.

Benefits seem to come gradually from improved blood flow, said Dr. Zoher Ghogawala, a neurosurgeon at Yale University in New Haven, Conn., who reported on the study at the annual meeting of the Congress of Neurological Surgeons. “After 1 month, there was no change in any of the domains we measured,” he said. “However, if we followed these patients for a year, there was significant improvement.”

The benefit of surgery also appeared to be most pronounced in those with a right-sided lesion or impairment in middle cerebral artery blood flow.

Although carotid endarterectomy is a well-established technique to treat carotid stenosis as a means of preventing stroke, its effects on cognitive function are poorly understood, Dr. Ghogawala said.

To learn more, he and his colleagues enrolled 36 patients from three sites. Overall, 61% had right-sided stenosis and 39% had left-sided stenosis; 54% were male, and 14% were symptomatic at presentation.

To estimate the extent that these patients’ circulation was compromised, the researchers generated quantitative phase-contrast magnetic resonance angiography (qMRA) flow maps for their internal and middle cerebral arteries. This technology images blood flow in multiple phases of the cardiac cycle and then calculates volume, velocity, and direction.

The researchers used this technique because conventional MR techniques usually do not show changes in blood flow.

Using these data, they calculated the ratio of contralateral to ipsilateral flow rates. They found that 12 patients had middle cerebral artery (MCA) flow impairment (defined as at least 15% less flow than the contralateral side) and 18 had impairment of internal carotid artery flow.

Lower blood flows were associated with a higher rate of stenosis. “It’s what you might expect,” said Dr. Ghogawala, who also is director of the Wallace Trials Center at Greenwich (Conn.) Hospital.

Following surgery, new qMRA maps showed improved blood flow in these patients. Of the 12 patients who had preoperative impairment in MCA blood flow, 10 had improved flow after surgery.

After a month, there were no significant improvements in cognitive functioning. But in 29 patients who completed follow-up at 1 year, there was improvement in executive functioning (as measured by the Trail Making Test, Part B), verbal fluency (on the Controlled Oral Word Association FAS test), and memory (total recall score on the Hopkins Verbal Learning Test). The changes were statistically significant (P less than .05).

Scores improved on the Trail Making Test in all 9 patients with improvement in blood flow following surgery, compared with 8 of 20 patients with no improvement in blood flow.

The presence of a right-sided lesion and impairment in middle cerebral artery blood flow were both significant, independent predictors of improved Trail Making Test scores.

Dr. Ghogawala said that patients with those features may have benefited the most because their cognitive function had been most impaired by their constricted blood flow.

“Further study is needed to understand the cerebral flow limitations associated with reversible dementia in some patients,” he concluded.

Dr. Ghogawala disclosed that one of his coauthors received research support from VasSol Inc., the company that made the technology for producing the qMRA maps used in the study. Another coauthor owns shares in the company.

SAN FRANCISCO – Cognitive function improved for most patients in the year after they underwent endarterectomy for carotid stenosis, according to the results of an ongoing prospective study.

Benefits seem to come gradually from improved blood flow, said Dr. Zoher Ghogawala, a neurosurgeon at Yale University in New Haven, Conn., who reported on the study at the annual meeting of the Congress of Neurological Surgeons. “After 1 month, there was no change in any of the domains we measured,” he said. “However, if we followed these patients for a year, there was significant improvement.”

The benefit of surgery also appeared to be most pronounced in those with a right-sided lesion or impairment in middle cerebral artery blood flow.

Although carotid endarterectomy is a well-established technique to treat carotid stenosis as a means of preventing stroke, its effects on cognitive function are poorly understood, Dr. Ghogawala said.

To learn more, he and his colleagues enrolled 36 patients from three sites. Overall, 61% had right-sided stenosis and 39% had left-sided stenosis; 54% were male, and 14% were symptomatic at presentation.

To estimate the extent that these patients’ circulation was compromised, the researchers generated quantitative phase-contrast magnetic resonance angiography (qMRA) flow maps for their internal and middle cerebral arteries. This technology images blood flow in multiple phases of the cardiac cycle and then calculates volume, velocity, and direction.

The researchers used this technique because conventional MR techniques usually do not show changes in blood flow.

Using these data, they calculated the ratio of contralateral to ipsilateral flow rates. They found that 12 patients had middle cerebral artery (MCA) flow impairment (defined as at least 15% less flow than the contralateral side) and 18 had impairment of internal carotid artery flow.

Lower blood flows were associated with a higher rate of stenosis. “It’s what you might expect,” said Dr. Ghogawala, who also is director of the Wallace Trials Center at Greenwich (Conn.) Hospital.

Following surgery, new qMRA maps showed improved blood flow in these patients. Of the 12 patients who had preoperative impairment in MCA blood flow, 10 had improved flow after surgery.

After a month, there were no significant improvements in cognitive functioning. But in 29 patients who completed follow-up at 1 year, there was improvement in executive functioning (as measured by the Trail Making Test, Part B), verbal fluency (on the Controlled Oral Word Association FAS test), and memory (total recall score on the Hopkins Verbal Learning Test). The changes were statistically significant (P less than .05).

Scores improved on the Trail Making Test in all 9 patients with improvement in blood flow following surgery, compared with 8 of 20 patients with no improvement in blood flow.

The presence of a right-sided lesion and impairment in middle cerebral artery blood flow were both significant, independent predictors of improved Trail Making Test scores.

Dr. Ghogawala said that patients with those features may have benefited the most because their cognitive function had been most impaired by their constricted blood flow.

“Further study is needed to understand the cerebral flow limitations associated with reversible dementia in some patients,” he concluded.

Dr. Ghogawala disclosed that one of his coauthors received research support from VasSol Inc., the company that made the technology for producing the qMRA maps used in the study. Another coauthor owns shares in the company.

SAN FRANCISCO – Cognitive function improved for most patients in the year after they underwent endarterectomy for carotid stenosis, according to the results of an ongoing prospective study.

Benefits seem to come gradually from improved blood flow, said Dr. Zoher Ghogawala, a neurosurgeon at Yale University in New Haven, Conn., who reported on the study at the annual meeting of the Congress of Neurological Surgeons. “After 1 month, there was no change in any of the domains we measured,” he said. “However, if we followed these patients for a year, there was significant improvement.”

The benefit of surgery also appeared to be most pronounced in those with a right-sided lesion or impairment in middle cerebral artery blood flow.

Although carotid endarterectomy is a well-established technique to treat carotid stenosis as a means of preventing stroke, its effects on cognitive function are poorly understood, Dr. Ghogawala said.

To learn more, he and his colleagues enrolled 36 patients from three sites. Overall, 61% had right-sided stenosis and 39% had left-sided stenosis; 54% were male, and 14% were symptomatic at presentation.

To estimate the extent that these patients’ circulation was compromised, the researchers generated quantitative phase-contrast magnetic resonance angiography (qMRA) flow maps for their internal and middle cerebral arteries. This technology images blood flow in multiple phases of the cardiac cycle and then calculates volume, velocity, and direction.

The researchers used this technique because conventional MR techniques usually do not show changes in blood flow.

Using these data, they calculated the ratio of contralateral to ipsilateral flow rates. They found that 12 patients had middle cerebral artery (MCA) flow impairment (defined as at least 15% less flow than the contralateral side) and 18 had impairment of internal carotid artery flow.

Lower blood flows were associated with a higher rate of stenosis. “It’s what you might expect,” said Dr. Ghogawala, who also is director of the Wallace Trials Center at Greenwich (Conn.) Hospital.

Following surgery, new qMRA maps showed improved blood flow in these patients. Of the 12 patients who had preoperative impairment in MCA blood flow, 10 had improved flow after surgery.

After a month, there were no significant improvements in cognitive functioning. But in 29 patients who completed follow-up at 1 year, there was improvement in executive functioning (as measured by the Trail Making Test, Part B), verbal fluency (on the Controlled Oral Word Association FAS test), and memory (total recall score on the Hopkins Verbal Learning Test). The changes were statistically significant (P less than .05).

Scores improved on the Trail Making Test in all 9 patients with improvement in blood flow following surgery, compared with 8 of 20 patients with no improvement in blood flow.

The presence of a right-sided lesion and impairment in middle cerebral artery blood flow were both significant, independent predictors of improved Trail Making Test scores.

Dr. Ghogawala said that patients with those features may have benefited the most because their cognitive function had been most impaired by their constricted blood flow.

“Further study is needed to understand the cerebral flow limitations associated with reversible dementia in some patients,” he concluded.

Dr. Ghogawala disclosed that one of his coauthors received research support from VasSol Inc., the company that made the technology for producing the qMRA maps used in the study. Another coauthor owns shares in the company.