Middle cerebral artery pulsatility index and cognitive improvement after carotid endarterectomy for symptomatic stenosis

Abstract

Object 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. Methods 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. Results 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). Conclusions 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).

Cerebrolysin effects on neurological outcomes and cerebral blood flow in acute ischemic stroke

“…As it has been proposed, cerebral autoregulatory mechanism contributes to the maintenance of sufficient mean flow velocity and decrease in the peripheral resistance in cerebral arteries to perfuse the ipsilateral hemisphere after the development of stroke. 20 The TCD ultrasound examination is a tool for determining the mean flow velocity and PI of cerebral arteries. An increased mean flow velocity of cerebral artery measured by TCD examination could be interpreted as an indirect indicative of increasing cerebral perfusion.…”

“…The PI was defined as the difference between peak systolic and end-diastolic velocities divided by the mean flow velocity of the same artery. 20 The NIHSS and TCD examinations were repeated on days 30, 60, and 90 during the follow-up period. All patients whose NIHSS scores were 0–1 or had a reduction in their NIHSS score more than 6 scores compared to their baseline NIHSS values were considered as responders.…”

Carotid Atherosclerosis is Associated with Middle Cerebral Artery Pulsatility Index

“…Cerebral autoregulatory mechanisms will in these situations often reduce peripheral cerebral resistance. 49 In a population-based sample of middle-aged adults, ultrasound-derived indices of carotid atherosclerosis and MCA PI were associated, even after adjustment for established cardiovascular risk factors. However, the overall explained variance of MCA PI was low, suggesting other factors than atherosclerosis and cardiovascular risk factors to play an important role for MCA PI.…”

“…Lastly, it is important to emphasize that the results of our study are mainly applicable to subjects without carotid stenosis or eventual tandem lesions. Cerebral autoregulatory mechanisms will in these situations often reduce peripheral cerebral resistance …”

Cerebrolysin for functional recovery in patients with acute ischemic stroke: a meta-analysis of randomized controlled trials

“…Further subgroup analysis indicated that cerebrolysin showed a superiority in patients with severe AIS. The cerebral autoregulatory mechanism made the spontaneous recovery of patients with AIS possible, especially in those with mild ischemic stroke 28. A high rate of spontaneous recovery under placebo might reduce the superiority of the cerebrolysin treatment arm.…”