Influence of cerebrovascular reactivity on outcome of the patients with ≥50% symptomatic unilateral middle cerebral artery stenosis

Cerebral Vasoreactivity in a Fabry Disease Patient

BACKGROUND

Fabry disease (FD) is a rare X-linked multisystem lysosomal storage disease caused by partial or total deficiency of a-galactosidase A (GLA). A progressive involvement of the kidneys, heart, and brain arteries has been reported. Using the transcranial color-coded duplex Doppler (TCCD), we report the case of a Fabry disease (FD) patient with a reduction in the cerebrovascular reactivity of the basilar artery (BA).

METHODS

A 46-year-old male asymptomatic FD patient underwent ultrasound intracranial investigation.

CASE PRESENTATION

We report the case of a 46-year-old man affected by asymptomatic FD, who presented to our observation for episodes of vertigo. Cerebral MRI and AngioMRI were found to be normal. There was no postural hypotension observed. Otolaryngology and cardiac examinations revealed no pathological condition. A TCCD showed normal cerebral vascular reactivity (CVR) in the bilateral middle cerebral arteries (MCA), breath-holding index (BHI) was 1.3 in the right MCA (RMCA) and 1.4 in left MCA (LMCA), and BHI in the basilar artery (BA) was reduced (BHI: 0,56).

CONCLUSION

This case suggests an earlier alteration of CVR in the posterior cerebral circulation than in the anterior cerebral circulation in an asymptomatic FD patient. This alteration of CVR may be an earlier marker of FD diagnosis.

Transcranial Color-Coded Duplex Ultrasound for Assessing Cerebrovascular Reserve in Intracranial Dissection with Aneurysm

Intracranial artery dissection (IAD) is an uncommon cause of cerebral ischemia. It may lead to symptoms due to rupture of subadventitial aneurysms or thromboembolism from subintimal disruption. Severe stenosis may lead to reduced cerebrovascular reserve (CVR). While there are many methods of assessing CVR, we report a case of IAD with hemodynamic complications diagnosed by transcranial color-coded duplex (TCCD) ultrasonography. Our patient is a 38-year-old female who presented with a 2-month history of nausea, then feeling faint whenever she got up suddenly. On the day of admission, she had gotten up to walk, felt nauseous, and the left upper limb felt “funny,” after which she lost consciousness. Clinical and neurological examination was normal. Brain magnetic resonance (MR) imaging was normal. MR angiogram and subsequent computed tomography (CT) angiogram showed flow attenuation in the M1 segment of the right middle cerebral artery (RMCA), with a possible flap. Catheter angiography was suggestive of a dissection with 2.7 mm pseudoaneurysm. TCCD showed very high velocities in the RMCA. The Breath-Holding Index (BHI) was 0.56, suggestive of reduced CVR in the RMCA territory. Acetazolamide-enhanced single-photon emission CT showed reduced right frontal CVR. She was given clopidogrel for secondary prevention, and has remained well. BHI as measured by TCCD is a new method for assessing CVR in patients with cerebral ischemia.

Improvement of Cerebrovascular Reserve by Percutaneous Transluminal Angioplasty for Symptomatic Middle Cerebral Artery Stenosis

Objective

The purpose of this study was to investigate the efficacy of percutaneous transluminal angioplasty (PTA) for symptomatic middle cerebral artery stenosis by analyzing cerebral blood flow (CBF).

Methods

Between January 2016 and December 2018, six patients with symptomatic middle cerebral artery stenosis underwent CBF analysis by single-photon emission computed tomography (SPECT) with acetazolamide challenge before and after PTA for stenosis. They were retrospectively reviewed, and the blood flow in the area of the affected middle cerebral artery before and after angioplasty was compared.

Results

The mean stenosis rate and length of lesion before angioplasty were 76.4 ± 5.4% and 6.5 ± 2.1 mm, respectively. Balloon angioplasty without stenting was performed on all patients. The mean residual stenosis rate just after angioplasty was 45.4 ± 9.3%. No periprocedual complications developed, and there were no notable cerebral ischemic events during the postprocedural follow-up period. One patient underwent repeat angioplasty for restenosis. Although there was only a mild decrease in blood flow at rest, the cerebrovascular reserve (CVR) in the area of the affected middle cerebral artery was markedly decreased before angioplasty (mean, 3.6 ± 4.3%). After angioplasty, the CVR was significantly improved (mean, 18.0 ± 4.7%, p <0.01).

Conclusions

PTA for symptomatic middle cerebral artery stenosis can be safely performed using appropriate interventional techniques for select patients. Reduced CVR due to stenosis can be improved after angioplasty, which may reduce the risk of cerebral ischemic events.

Assessment of the Cerebral Hemodynamic Benefits of Carotid Artery Stenting for Patients with Preoperative Hemodynamic Impairment Using Cerebral Single Photon Emission Computed Tomography (SPECT) and Carbon Dioxide Inhalation

BACKGROUND The aim of this study was to evaluate the effects of carotid artery angioplasty and carotid artery stenting (CAS) on cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) in patients with preoperative cerebrovascular hemodynamic impairment. MATERIAL AND METHODS Seventeen patients with unilateral severe internal carotid artery (ICA) stenosis and ipsilateral CVR impairment underwent CAS. CBF and CVR were measured by single photon emission computed tomography (SPECT) with inhalation of carbon dioxide (CO2) one week before and three months after CAS. Sixty-eight ROIs in the middle cerebral artery (MCA) territory were analyzed in 17 patients. RESULTS Before CAS, CVR was impaired in all ROIs. CBF was impaired in 16 ROIs (23.5%). The percentage of ROIs with impaired CBF was significantly increased in patients with ≥90% carotid artery stenosis (p=0.047) without collateral flow through the circle of Willis (p=0.005). CAS significantly increased CVR in ROIs with a normal preoperative CBF and impaired CVR, indicating mild hemodynamic impairment (0.9±6.7% vs. 4.9±8.6%) (p=0.014). CAS significantly increased CBF in ROIs with preoperative impaired CBF and impaired CVR, indicating severe hemodynamic impairment (79.1±7.5% vs. 86.7±10.0%) (p<0.001). Following CAS, ROIs with normal CBF and impaired CVR had a significantly increased percentage of improved CVR (p=0.047); ROIs with impaired CBF and impaired CVR had a significantly increased percentage of improved CBF (p=0.027). CONCLUSIONS The severity of preoperative hemodynamic impairment, which is related to the degree of carotid artery stenosis and cerebral collateral flow, may influence hemodynamic benefits by CAS.

Transcranial Direct Current Stimulation in Patients with Prolonged Disorders of Consciousness: Combined Behavioral and Event-Related Potential Evidence

Background

The electrophysiological evidence supporting the therapeutic efficacy of multiple transcranial direct current stimulation (tDCS) sessions on consciousness improvement in patients with prolonged disorders of consciousness (DOCs) has not been firmly established.

Objectives

To assess the effects of repeated tDCS in patients with prolonged DOCs by Coma Recovery Scale-Revised (CRS-R) score and event-related potential (ERP).

Method

Using a sham-controlled randomized double-blind design, 26 patients were randomly assigned to either a real [five vegetative state (VS) and eight minimally conscious state (MCS) patients] or sham (six VS and seven MCS patients) stimulation group. The patients in the real stimulation group underwent 20 anodal tDCS sessions of the left dorsolateral prefrontal cortex (DLPFC) over 10 consecutive working days. The CRS-R score and P300 amplitude and latency in a hierarchical cognitive assessment were recorded to evaluate the consciousness level before tDCS and immediately after the 20 sessions.

Results

The intra-group CRS-R analysis revealed a clinically significant improvement in the MCS patients in the real stimulation group. The inter-group CRS-R analysis showed a significant difference in CRS-R between VS and MCS patients at baseline in both the real and sham stimulation groups. The intra-group ERP analysis revealed a significant increase in P300 amplitude after tDCS in the MCS patients in the real stimulation group, but no significant differences in P300 latency. For the inter-group ERP analysis, we observed significant differences regarding the presence of P300 at baseline between the VS and MCS patients in both groups.

Conclusion

The repeated anodal tDCS of the left DLPFC could produce clinically significant improvements in MCS patients. The observed tDCS-related consciousness improvements might be related to improvements in attention resource allocation (reflected by the P300 amplitude). The findings support the use of tDCS in clinical practice and ERP might serve as an efficient electrophysiological assessment tool in patients with DOCs.