Changes in cerebrovascular reactivity as a marker of cognitive impairment risk: a transcranial Doppler study.

Abstract

Introduction: Post-stroke cognitive impairment (PSCI) and dementia affect short- and long-term outcome after stroke and can persist even after recover from a physical handicap. The process underlying PSCI is not yet fully understood. Transcranial Doppler ultrasound (TCD) is a feasible method to investigate cerebrovascular aging or dementia, through the pulsatility index (PI), the cerebrovascular reactivity (e.g. the Breath-Holding Index (BHI)) and the functional Transcranial Doppler sonography (fTCD). Aim of the study was to assess the usefulness of PI, BHI, Resistance Index (RI) and fTCD in evaluating the risk of cognitive impairment evolution in patients with minor stroke (MS), compared to patients with transient ischemic attack (TIA) and to healthy controls (HC).

Material and methods: PI, RI, BHI and fTCD were evaluated in the middle cerebral artery (MCA) of MS patients, TIA and HC. Patients with MS and TIA were enrolled within six days from the cerebrovascular event (acute phase) and the tests were repeated after 180±15 days from t0 (control phase). During the TCD recording, particular sections of MoCA test and FAB test were performed.

Results: 43 subjects were enrolled: 13 MS, 16 TIA and 14 HC. MFV analysis in the acute phase demonstrated no difference between MFVs at rest vs MFVs during MoCA/FAB tests in TIA and MS (acute phase), a significant increase of MFVs during MoCA/FAB tests vs MFVs at rest in HC (p<0.01), a statistically significant difference in the PI of MS vs HC at rest (p=0.048) and in BHI between HC vs MS (p<0.001) and HC vs TIA (p<0.01). In the control phase the absence of a statistically significant difference in MFVs was observed only in MS patients (MFVs at rest vs MFVs during MoCA) and PI and BHI values were in the normal range both in MS and TIA. No correlation was observed between MoCA test results and MFV, PI or RI, in any of the three groups.

Conclusion: A different cerebral vasoreactivity, in terms of no increase in MFV, was found when performing cognitive tasks in patients with MS and TIA compared to HC in the acute phase. TCD is a fundamental tool to study cerebral vasoreactivity.