Chien-Jung Lu

Carotid atherosclerosis, intima media thickness and risk factors—an analysis of 1781 asymptomatic subjects in Taiwan

The aim of this study was to investigate the association of intima media thickness (IMT) and plaque with risk factors for atherosclerosis in asymptomatic subjects in Taiwan. Between 1998 and 2001, the study recruited 1781 asymptomatic subjects (1131 men and 650 women [mean age, 49 years; range 18-85 years]). These were examined by B-mode ultrasound to measure the IMT at the far wall of the common carotid artery (CCA) and the extent of plaque formation. A wide range of vascular risk factors including age, gender, smoking, body mass index, blood chemistry, and previous history were surveyed. The mean (+/-S.D.) IMT observed was 0.68 (+/-0.12) and 0.66 (+/-0.11) mm for men and women, respectively, (P=0.0008). The mean (S.D.) IMT of the CCA was 0.66 (+/-0.12) mm on the right side and 0.68 (+/-0.12) mm on the left side (P=0.0004). IMT increased with aging, according to the equation IMT=(0.005xage in years)+0.403 [corrected]. Higher IMT was associated with male gender, and IMT was greater in the left CCA. About 36.9% of subjects had carotid plaques. The percentage of plaque increased with aging. The plaque prevalence was positively associated with IMT. The value of IMT over the cut point of 0.68 mm correlated with obviously increased risk of carotid atherosclerosis. Age, systolic blood pressure and fasting blood sugar were independent risk factors related to both carotid atherosclerosis and thick IMT.

Imaging in the diagnosis and follow-up evaluation of vertebral artery dissection.

The purpose of this report is to discuss the value of ultrasonographic examination in the diagnosis and follow‐up evaluation of vertebral artery dissection. We collected data on 8 patients with 11 pathologic vessels: 9 were affected intracranially and 6 were affected extracranially. Four vessels were affected in both intracranial and extracranial segments. Extracranial color‐flow duplex sonography could detect abnormalities in every extracranial vertebral artery dissection. Most abnormal findings were non‐specific, including severely reduced flow, absence of flow, and absence of diastolic flow. A specific finding (intramural hematoma) was noted in one artery. Abnormal transcranial color‐coded sonographic findings included absence of flow, reduced velocity and reversed flow direction. Three intracranial dissecting arteries showed normal findings on transcranial color‐coded sonography. Ultrasonographic follow‐up study revealed evidence of improvement; this was noted almost exclusively in the extracranial segments of the vertebral artery but infrequently in the intracranial segment. Extracranial color‐flow duplex sonography is sensitive in the detection of extracranial vertebral artery dissection, both in initial diagnosis and in follow‐up evaluation.

Long-Term Results of Elective Stenting for Severe Carotid Artery Stenosis in Taiwan

Stenting for severe carotid stenosis has been proposed as an alternative for patients with high surgical risk for endarterectomy, but its effectiveness and safety has never been evaluated in large case series in a pure Asian population. One hundred and eighteen ethnic Chinese patients (mean age 72.8 years) with 129 severely narrowed carotid arteries were stented electively using self-expanding stents. The mean pre-treatment diameter stenosis was 85% and final residual diameter stenosis 14%. The peri-procedural stroke and death rate was 4.2%. One (0.8%) late ischemic stroke and 2 (1.7%) deaths occurred during a mean follow-up of 16.3 months, and the restenosis rate was 3.1%. Carotid stenting, therefore, can be done safely and effectively in Chinese patients.

Clinical and ultrasonographic manifestations in major causes of common carotid artery occlusion.

Background and Purpose. Atherosclerosis is the main cause of common carotid artery occlusion in most reports. This study aimed to identify the major causes of common carotid artery occlusion and compare the clinical features and carotid duplex ultrasonography findings of patients with common carotid artery occlusion attributable to each cause. Methods. Patients with common carotid artery occlusion documented by carotid duplex ultrasonography at the Neurovascular Laboratory (National Taiwan University Hospital) from 1988 to 2003 were included. Medical records and ultrasonographic findings were reviewed in detail to clarify the possible etiology of common carotid artery occlusion. Results. A total of 44 patients (male, 27 [61%]; female, 17 [39%]; mean age, 58 years) had common carotid artery occlusion attributable to a carotid duplex ultrasonography–identifiable cause. The causes of common carotid artery occlusion included atherosclerosis (17 [39%]), Takayasus arteritis (11 [25%]), postirradiation arteriopathy (7 [16%]), cardiac embolism (6 [14%]), syphilis (1), blunt trauma (1), and homocystinuria (1). Among the patients with common carotid artery occlusion due to the 4 major causes, 27 (66%) had ischemic stroke and 14 (34%) had no symptoms or nonlocalizing symptoms. The frequency of symptomatic com mon carotid artery occlusion was 83% in those with cardioembolism, 76% in those with atherosclerosis, 71% in those with postirradiation arteriopathy, and 36% in those with Takayasus arteritis. Common carotid artery occlusion usually involved the carotid bulb and distal common carotid artery in atherosclerosis (88%) and postirradiation arteriopathy (100%), but not in Takayasus arteritis (27%). Echogenicity of occluded material was heterogeneous in atherosclerosis and post‐irradiation arteriopathy patients but homogeneous in all Takayasus arteritis patients. The authors postulate that the thrombotic mechanism might differ according to etiology. Con clusions. The causes of common carotid artery occlusion are diverse. Atherosclerosis, Takayasus arteritis, and post‐irradiation arteriopathy are the most common causes of com mon carotid artery occlusion in Taiwan. The clinical features, pathophysiology, and carotid duplex ultrasonography findings vary according to the cause of common carotid artery occlusion.

Transcranial Color-Coded Sonography for the Detection of Middle Cerebral Artery Stenosis

The purpose of this study was to validate the accuracy and criteria of transcranial color‐coded sonography (TCCS) in detecting severe middle cerebral artery (MCA) stenosis.

The Hemodynamic Effects of Internal Carotid Artery Stenting: A Study with Color-Coded Duplex Sonography

Background: Stenting has been used as an alternative treatment for patients with internal carotid artery (ICA) stenosis. Color-coded duplex sonography (CDS) is able to measure not only the prestenting stenosis but also the poststenting hemodynamic changes. The purpose of this study was to quantify, using CDS, the hemodynamic changes after ICA stenting. Methods: Both symptomatic and asymptomatic patients were included in this study. The degree of ICA stenosis before stenting was required to be more than 50%. Thirty-two treated ICAs were included to compare the prestenting and poststenting CDS findings, including the diameter and cross-sectional area of the lumen, the flow peak systolic and end-diastolic velocities, the resistivity index and the amount of flow in bilateral extracranial carotid and vertebral arteries. Results: After stenting, the turbulent flow pattern in the stenotic ICA recovered to laminar flow, and the reversed ophthalmic flow direction normalized. Of the CDS parameters applied to evaluate the effect of stenting on ICA stenosis, the diameter, residual area, peak systolic velocity, diastolic velocity and the ration of systolic flow velocity ratio in the ICA to that in the common carotid artery (CCA) were altered significantly. The mean area and residual area of these stenotic ICAs showed increases of 24% (p = 0.005) and 84% (p = 0.001) after ICA stenting, respectively. The mean peak systolic flow velocity significantly decreased by 71%. The mean diastolic flow velocity also significantly decreased (by 77%). Both the systolic and diastolic velocities of the ipsilateral CCA significantly increased after stenting. The amount of flow in the contralateral ICA decreased significantly after stenting. The change in the amount of flow in the vertebral arteries after ICA stenting was insignificant. Conclusions: The results of this CDS study clearly demonstrated the hemodynamic changes after ICA stenting. The carotid stenting significantly changed the ICA flow pattern, diameter, residual area, peak systolic velocity and ICA to CCA velocity ratio.

Prediction of infarct growth and neurologic deterioration in patients with positive perfusion-diffusion mismatch

BACKGROUND To assess the value of baseline clinical severity and perfusion-diffusion mismatch as predictors for further infarct growth and clinical outcome. METHODS Patients with acute ischemic stroke and initial perfusion-diffusion mismatch within 72 h were enrolled. Baseline perfusion defects on time-to-peak (TTP) and cerebral blood volume (CBV) maps were measured. Infarct volume and stroke severity were assessed by diffusion-weighted image (DWI) and NIHSS, and were repeatedly assessed 7 days later. The predictive value of baseline NIHSS and perfusion defects on further infarct growth and neurologic deterioration was determined. RESULTS Fifty-two patients (mean age 68.3±12.8 years, 42% women) were enrolled. CBV defects were significantly associated with infarct growth (CBV, p=0.02). Initial stroke severity, but not TTP and CBV mismatch (p=0.65 and 0.76, respectively), significantly inversely correlated with neurologic deterioration (p=0.001). CONCLUSIONS In patients with mismatch, those with severe symptoms initially are more likely to have infarct growth, while those with minor symptoms tend to suffer from larger extent of neurologic deterioration within 1 week. CBV is associated with further infarct growth but not clinical deterioration.

Fatal Intoxication Using Amantadine and Pramipexole in a Uremic Patient

We report a fatal intoxication in a 59-year-old woman who had uremia undergoing hemodialysis, and then took amantadine and pramipexole for Parkinsonian tremor. Toxic manifestation includes myoclonus, ataxia, confusion and sudden death. This report highlights the fact that using amantadine and pramipexole may be fatal in patients with uremia even undergoing hemodialysis.

Postprocedural complications after angioplasty with stenting of the internal carotid artery.

Short Reports infarctions. Occlusion of perforating arteries arising from the distal VA is likely to be responsible for such infarctions, and the length of the occlusion should be minimized as much as possible to avoid this complication [3, 4]. Treatment of VA dissection involving the PICA origin is the most problematic [8, 9]: inadvertent occlusion of the PICA causes serious brainstem/cerebellar infarctions, whereas incomplete packing of the dissection with the hope of sparing the PICA is no more effective or safe. In summary, endovascular occlusion using GDC is an effective treatment for ruptured VA dissection. However, VA dissection involving the PICA origin, bilateral VA dissection, and VA dissection with hypoplastic contralateral VA remain therapeutic challenges.

Lack of Association Between Total Serum Homocysteine and Extracranial Cerebral Flow

BACKGROUND/PURPOSE High homocysteine (Hcy) concentration is associated with slow coronary flow. This study examined the association between Hcy and hemodynamic status in the extracranial cerebral arteries in healthy individuals. METHODS A total of 535 healthy adults underwent physical examination and duplex ultrasonography of the extracranial carotid and vertebral arteries, and blood laboratory tests, including biochemistry and serum total Hcy. Flow hemodynamic parameters including velocity, resistance, and volume of the carotid and vertebral arteries were measured. Multiple regression analysis was performed to examine the association between Hcy and the flow parameters. RESULTS Participants with higher Hcy were more likely to have a lower systolic velocity of the internal carotid artery (p = 0.01) and vertebral artery (p < 0.001), and lower resistance of the vertebral artery (p = 0.004). However, the multiple-adjusted means of the flow velocity, resistance, and flow volume of the carotid or vertebral artery were not significantly different across quartiles of Hcy. When Hcy was treated as a continuous variable, there was still no significant relationship between Hcy levels and the aforementioned hemodynamic status. CONCLUSION Our results did not support the hypothesis that the levels of Hcy are associated with the flow velocity, resistance, and volume of the extracranial cerebral artery in healthy individuals.