Florence Fan

Risk factors for incident dementia after stroke and transient ischemic attack

We hypothesized that chronic brain changes are important substrates for incident dementia after stroke and transient ischemic attack (TIA).

Rituximab reduces attacks in Chinese patients with neuromyelitis optica spectrum disorders.

We evaluated the safety and efficacy of rituximab in seven Chinese patients with neuromyelitis optica (NMO) or neuromyelitis optica syndrome disorders (NMOSD) in a tertiary medical center in Hong Kong. After rituximab induction, five patients became relapse-free and two had 50% reduction of relapses over a median follow-up of 24 months. No further deterioration of functional status, measured by the Expanded Disability Status Scale, was observed in all patients. Infusions were well tolerated except in two patients who developed transient hypotension. Rituximab reduced clinical relapse and prevented neurological deterioration in a small cohort of Chinese patients with NMO or NMOSD.

Computational fluid dynamics modeling of symptomatic intracranial atherosclerosis may predict risk of stroke recurrence.

Background Patients with symptomatic intracranial atherosclerosis (ICAS) of ≥70% luminal stenosis are at high risk of stroke recurrence. We aimed to evaluate the relationships between hemodynamics of ICAS revealed by computational fluid dynamics (CFD) models and risk of stroke recurrence in this patient subset. Methods Patients with a symptomatic ICAS lesion of 70–99% luminal stenosis were screened and enrolled in this study. CFD models were reconstructed based on baseline computed tomographic angiography (CTA) source images, to reveal hemodynamics of the qualifying symptomatic ICAS lesions. Change of pressures across a lesion was represented by the ratio of post- and pre-stenotic pressures. Change of shear strain rates (SSR) across a lesion was represented by the ratio of SSRs at the stenotic throat and proximal normal vessel segment, similar for the change of flow velocities. Patients were followed up for 1 year. Results Overall, 32 patients (median age 65; 59.4% males) were recruited. The median pressure, SSR and velocity ratios for the ICAS lesions were 0.40 (−2.46–0.79), 4.5 (2.2–20.6), and 7.4 (5.2–12.5), respectively. SSR ratio (hazard ratio [HR] 1.027; 95% confidence interval [CI], 1.004–1.051; P = 0.023) and velocity ratio (HR 1.029; 95% CI, 1.002–1.056; P = 0.035) were significantly related to recurrent territorial ischemic stroke within 1 year by univariate Cox regression, respectively with the c-statistics of 0.776 (95% CI, 0.594–0.903; P = 0.014) and 0.776 (95% CI, 0.594–0.903; P = 0.002) in receiver operating characteristic analysis. Conclusions Hemodynamics of ICAS on CFD models reconstructed from routinely obtained CTA images may predict subsequent stroke recurrence in patients with a symptomatic ICAS lesion of 70–99% luminal stenosis.

Evolution of intracranial atherosclerotic disease under modern medical therapy.

Understanding how symptomatic intracranial atherosclerotic disease (ICAD) evolves with current medical therapy may inform secondary stroke prevention.

Evaluation of Carotid Angioplasty and Stenting for Radiation-Induced Carotid Stenosis

Background and Purpose— We aimed to evaluate the procedural safety, clinical, and angiographic outcome of carotid angioplasty and stenting for high-grade (≥70%) radiation-induced carotid stenosis (RIS) using atherosclerotic stenosis (AS) as a control. Methods— In this 6-year prospective nonrandomized study, we compared the carotid angioplasty and stenting outcome of 65 consecutive patients (84 vessels) with RIS with that of a control group of 129 consecutive patients (150 vessels) with AS. Study end points were 30-day periprocedural stroke or death, ipsilateral ischemic stroke, technical success, procedural characteristics, instent restenosis (ISR; ≥50%) and symptomatic ISR. Results— The median follow-up was 47.3 months (95% confidence interval, 26.9–61.6). Imaging assessment was available in 74 vessels (RIS) and 120 vessels (AS) in 2 years. Comparing RIS group with AS group, the rates of periprocedural stroke or death were 1.5% (1/65) versus 1.6% (2/129; P=1); ipsilateral ischemic stroke rates were 4.6% (3/65) versus 4.7% (6/129; P=1); the annual risks of ipsilateral ischemic stroke were 1.2% (3 patient/254.7 patient year) versus 1.2% (6 patient/494.2 patient year; P=0.89); technical success rates were both 100%. Stenting of common carotid artery and the use of multiple stents was more common in the RIS group (P=0 in both cases); ISR rates were 25.7% (19/74) versus 4.2% (5/120; P<0.001); symptomatic ISR rates were 6.8% (5/74) versus 0.8% (1/120; P=0.031). Conclusions— The safety, effectiveness, and technical difficulty of carotid angioplasty and stenting for RIS are comparable with that for AS although it is associated with a higher rate of ISR. Clinical Trial Registration— This trial was not registered as enrollment started in 2006.

Delayed-onset dementia after stroke or transient ischemic attack

Patients surviving stroke without immediate dementia are at high risk of delayed‐onset dementia. Mechanisms underlying delayed‐onset dementia are complex and may involve vascular and/or neurodegenerative diseases.

Hemodynamic Impact of Systolic Blood Pressure and Hematocrit Calculated by Computational Fluid Dynamics in Patients with Intracranial Atherosclerosis

Success in clinical trials of intracranial atherosclerosis (ICAS) is related to accurate identification of high‐risk patients. Noninvasive computational fluid dynamics (CFD) of stenotic lesions may enhance therapeutic decision‐making. We determined whether physiologic parameters change downstream cerebral hemodynamics in patients with ICAS.

Translesional pressure gradient and leptomeningeal collateral status in symptomatic middle cerebral artery stenosis

Leptomeningeal collateral (LMC) status governs the prognosis of large artery occlusive stroke, although factors determining LMC status are not fully elucidated. The aim was to investigate metrics affecting LMC status in such patients by using computational fluid dynamics (CFD) models based on computed tomography angiography (CTA).

Correlation of non-vitamin K antagonist oral anticoagulant exposure and cerebral microbleeds in Chinese patients with atrial fibrillation

Background and purpose Cerebral microbleeds (CMBs) are radiological markers which predict future intracerebral haemorrhage. Researchers are exploring how CMBs can guide anticoagulation decisions in atrial fibrillation (AF). The purpose of this study is to evaluate the correlation of non-vitamin K antagonist oral anticoagulants (NOAC) exposure and prevalence of CMBs in Chinese patients with AF. Methods We prospectively recruited Chinese patients with AF on NOAC therapy of ≥30 days for 3T MRI brain for evaluation of CMBs and white matter hyperintensities. Patients with AF without prior exposure to oral anticoagulation were recruited as control group. Results A total of 282 patients were recruited, including 124 patients in NOAC group and 158 patients in control group. Mean duration of NOAC exposure was 723.8±500.3 days. CMBs were observed in 103 (36.5%) patients. No significant correlation was observed between duration of NOAC exposure and quantity of CMBs. After adjusting for confounding factors (ie, age, hypertension, labile hypertension, stroke history and white matter scores), previous intracerebral haemorrhage was predictive of CMBs (OR 15.28, 95% CI 1.81 to 129.16), particularly lobar CMBs (OR 5.37, 95% CI 1.27 to 22.6). While white matter score was predictive of mixed lobar CMBs (OR 1.65, 95% CI 1.1 to 2.5), both exposure and duration of NOAC use were not predictive of presence of CMBs. Conclusions In Chinese patients with AF, duration of NOAC exposure did not correlate with prevalence and burden of CMBs. Further studies with follow-up MRI are needed to determine if long-term NOAC therapy can lead to development of new CMBs.