[Show abstract][Hide abstract] ABSTRACT: We wanted to examine whether brain computed tomography (CT) perfusion can help to detect the reconstitution of cerebral hemodynamics and predict intracerebral hemorrhage (ICH) after carotid stenting.
From September 2002 to October 2009, data of 114 patients with carotid intervention were prospectively collected, and we retrospectively identified a total of 108 consecutive patients with unilateral carotid stenting. Brain CT perfusion was studied at three time points: 1 week before, and 1 week and 6 months after stenting. Cerebral blood volume (CBV), cerebral blood flow, and time to peak (TTP) of brain CT perfusion were examined at cortical and subcortical areas of middle cerebral artery (MCA) and posterior cerebral artery territory. The CBV, cerebral blood flow, and TTP ratios of stenting side/nonstenting side were used for comparison. The flow direction of ophthalmic artery was detected by sonography, and the presence of anterior communicating artery was examined on prestenting cerebral angiogram.
After carotid stenting, CBV and TTP ratios improved significantly in both MCA cortical and subcortical areas in patients with unilateral carotid stenosis (P < .01) but not in patients with bilateral carotid stenosis. Patients with reversed ophthalmic flow had better improvement of TTP in both MCA and posterior cerebral artery territories (P < .05) than patients with forward flow. However, no significant difference was found between patients with and patients without anterior communicating artery collateral (P > .05). The prestenting TTP ratio in MCA subcortical area was significantly higher in patients with poststenting ICH than patients without ICH (P = .0191).
Cerebral hemodynamics can be reconstituted within a few days after carotid revascularization, especially in patients with reversed ophthalmic flow. Prolonged TTP in prestenting MCA subcortical area may suggest a high risk of poststenting ICH.
Preview · Article · Jul 2012 · Journal of vascular surgery: official publication, the Society for Vascular Surgery [and] International Society for Cardiovascular Surgery, North American Chapter
[Show abstract][Hide abstract] ABSTRACT: Clinical research of cervicocranial fibromuscular dysplasia (FMD) is rare in Asian populations. Our study reviewed Taiwanese ischemic stroke patients with cervicocranial FMD and compared them with previous reports.
Between 2000 and 2011, we collected 19 consecutive cervicocranial FMD patients who received demographic registration, a blood test for excluding vasculitis, and comprehensive angiography. Cerebral ultrasound, vascular images and clinical outcomes (Barthel index, modified Rankin scale, recurrent stroke, or death) were monitored during follow-up.
Of the 19 patients, 16 (84%) had carotid FMD, while 7 (37%) had vertebral FMD. Only 2 investigated patients (13%) had renal FMD and 1 (5%) had cerebral aneurysm. 14 (74%) presented acute arterial dissection. All patients received medical treatment and had neither recurrent stroke nor dissection during follow-up. In the literature review of 225 FMD patients, 3.6% had recurrent stroke during follow-up, and some reported surgical procedure or angioplasty could give a good clinical outcome in progressing ischemia irrelevant to the cause of stenosis.
In Taiwanese cervicocranial FMD patients, arterial dissection was one of the most common clinical presentations. Most of our patients had isolated involvement of the cervicocranial artery and carried a favorable outcome under medical treatment.
Full-text · Article · Jan 2012 · European Neurology
[Show abstract][Hide abstract] ABSTRACT: The occurrence of silent ischemic lesions (SILs) is a common finding after carotid artery stenting (CAS). This study aimed to evaluate the impact of SILs on cognitive functioning following CAS.
The retrospective study separated 131 patients with unilateral carotid stenosis into three groups: medication only, MRI-evaluated CAS and CT-evaluated CAS, and compared the sociodemographic factors, post-CAS images and Mini-Mental State Examination scores performed before and 6-12 months after enrollment.
Seven minor strokes occurred in the 99 patients receiving CAS. SILs were detected in 12 of 55 patients with diffusion-weighted MR imaging (DWI) and in 3 of 37 patients with CT 1 week after CAS. In patients with DWI follow-up, the frequency of SILs was 8, 24, 43 and 60% in patients with 0-, 1-, 2- and 3-vessel coronary artery disease (p = 0.006). The frequency of SILs on DWI was 0, 32 and 33% in patients with improved, unchanged, or deteriorated cognitive functioning (p = 0.02). Such an association was not observed if based on SILs on CT or manifesting stroke.
The presence of coronary artery disease increases the risk for having post-CAS SILs, and the occurrence of SILs may be associated with cognitive changes after CAS.
No preview · Article · Nov 2011 · European Neurology
[Show abstract][Hide abstract] ABSTRACT: Leukoaraiosis (LA) affects cognition after stroke and reversal of LA may improve cognitive performance. We aimed to determine the impact of cerebral perfusion and circle of Willis (CoW) flow patterns on the extent of LA after carotid artery revascularization.
LA was scored on fluid-attenuated inversion recovery magnetic resonance (MR) images at the levels of the centrum semiovale and frontal horns in both cerebral hemispheres of 62 contiguous patients (men/women = 38/24, mean age = 63.2 ± 8.4 years, range 44-82) before and after unilateral carotid artery revascularization. The pre- and poststenting differences in LA scores, CoW flow pattern on MR angiography, and MR perfusion parameters were analyzed.
The total LA score decreased from 9.87 ± 0.65 to 8.33 ± 0.72 after stenting (p = 0.03). The CoW was complete in 21 subjects and incomplete in 41 subjects. The incomplete CoW group had a higher preoperative LA load and higher cerebral interhemispheric asymmetry index, both of which decreased significantly postoperatively.
CoW anomalies may contribute to LA in patients with carotid artery stenosis, and restoration of cerebral perfusion by carotid artery revascularization can reduce LA severity.
No preview · Article · Nov 2011 · Cerebrovascular Diseases
[Show abstract][Hide abstract] ABSTRACT: Various cerebral pathological changes have been reported to cause leukoaraiosis (LA). We hypothesized that circle of Willis (CoW) anomalies may contribute to LA in severe carotid artery stenosis victims through impaired cerebral autoregulation. We conducted a retrospective review on cerebral magnetic resonance (MR) patterns in patients with severe symptomatic carotid artery stenosis and compared white matter lesion (WML) load between subjects with and without complete CoW.
LA on fluid attenuation inversion recovery (FLAIR) MR images at the levels of the centrum semiovale and frontal horns in both cerebral hemispheres were scored in 106 patients with unilateral carotid artery stenosis (64 men and 42 women; mean age 68.7 ± 9.2 years, range 44-82). Subjects were divided into groups of complete and incomplete CoW according to cerebral MR angiography. Differences in the LA scores between the groups of complete and incomplete CoW were further analyzed.
Compared with those with incomplete configuration of the CoW, subjects with a complete CoW demonstrated a decreased WML load at the level of the centrum semiovale (2.78 ± 1.17 vs. 5.62 ± 2.12, p = 0.02) and frontal horns (2.21 ± 0.79 vs. 4.22 ± 1.83, p = 0.01).
Our results support the importance of a complete CoW since it may protect from WML in case of carotid stenosis.
No preview · Article · Aug 2011 · European Neurology
[Show abstract][Hide abstract] ABSTRACT: The purpose of the present study was to assess whether the direction of flow via the circle of Willis (CoW) changed after stenting for severe internal carotid artery (ICA) stenosis.
65 patients (38 men, mean age 63.2 +/- 8.4 years, range 44-82) with a symptomatic ICA occlusion were investigated. Magnetic resonance angiography was performed prior to and 1 week after carotid artery stenting (CAS). The pattern in the CoW was assessed.
One third of the subjects (35.38%) had a significantly altered flow pattern in the CoW after unilateral CAS, including blocked ipsilateral A1 segment collateral (n = 4), blocked contralateral A1 segment collateral (n = 5), blocked ipsilateral posterior communicating artery (PCoA) segment collateral (n = 4), blocked ipsilateral A1 segment and P1 segment collateral (n = 1), opening of ipsilateral A1 segment collateral (n = 5), opening of ipsilateral PCoA segment collateral (n = 3) and opening of ipsilateral P1 segment collateral (n = 1).
CoW segmental hypoplasia is not a static feature. Willisian collateralization with recruitment of the CoW segment (A1, P1 and PCoA) may be blocked after CAS. CAS also leads to the opening of new willisian collateralization, either for relief of reperfusion pressure or for other hypoperfused areas.
Full-text · Article · May 2009 · Cerebrovascular Diseases
[Show abstract][Hide abstract] ABSTRACT: The frequency, associated risk factors and associated vascular disorders in renal artery disease have not been studied in young ischemic stroke patients.
From February 1999 to June 2006, we retrospectively reviewed a total of 152 younger ischemic stroke patients (< or = 50 y/o). Another 30 older ischemic stroke patients (age > 50 y/o) were randomly selected and studied as controls. All 182 patients received cerebral angiography and concomitant abdominal aortography. The extent of vascular stenosis was calculated for the renal, cerebral and coronary arteries. Vascular risk factors were also studied.
Of the 152 younger patients, seven (4.6%) patients had renal artery disease including two (1.3%) with significant stenosis. There was no association between renal artery disease and vascular risk factors (p > 0.05). Patients with intracranial carotid and coronary artery disease had a significantly higher frequency of renal artery disease (p < 0.05).
Our results suggest that the frequency of renal artery disease is low in younger ischemic stroke patients. Intracranial carotid and coronary artery disease is associated with renal artery disease.
Preview · Article · Mar 2008 · Acta neurologica Taiwanica