Ping-Keung Yip

Subtypes of Ischemic Stroke: A Hospital-Based Stroke Registry in Taiwan (SCAN-IV)

BACKGROUND AND PURPOSE To better understand the clinical pattern and further elucidate the risk factors and outcome in different subtypes of cerebral infarction (CI) of the Chinese in Taiwan, we analyzed the National Taiwan University Hospital Stroke Registry in 1995 and performed an ethnic comparison with similar data banks. METHODS From the National Taiwan University Hospital Stroke Registry in 1995, 676 patients (383 men and 293 women; mean age, 64.9 years; SD, 13.8 years; range, 1 to 98 years) with CI were recruited for this analysis. CI was classified into five subtypes based on clinical manifestations, ultrasonographic studies, and neuroimaging findings: large-artery atherosclerosis, lacunae, cardioembolism, other less common determined causes, and undetermined cause. Vascular risk factors, extracranial carotid artery atherosclerosis, and 30-day case-fatality rates were investigated in each subtype of CI. RESULTS Of all CI patients, 17%, 29%, 20%, 6%, and 29% were classified as large-artery atherosclerosis, lacunae, cardioembolism, other determined causes, and undetermined cause subtypes, respectively. The present results were compared with those from eight similar Western stroke registries. The relative incidence of lacunar CI in Chinese patients was more common, but large-artery atherosclerotic CI was less common than in whites. Hypertension was frequently seen in CI patients, especially in those with lacunae (85%) and large-artery atherosclerosis (69%). Patients with cardioembolism had a higher percentage of atrial fibrillation (69%), left ventricular hypertrophy, and ischemic heart disease than the other patients. Patients with large-artery atherosclerosis had more vascular risk factors, such as hypertension, diabetes mellitus, smoking, and carotid stenosis. Cardioembolic patients had higher case-fatality rates than other CI patients. Of the cardioembolic patients, 17.3% and 21.8% died within 30 days and during hospitalization, respectively. CONCLUSIONS The proportion of CI subtypes varied in different stroke registries. This may be partly due to applied classification criteria and racial-ethnic differences. Awareness of the risk factors and outcome in each subtype of stroke may afford further insights into the surveillance and treatment of cerebrovascular disease.

Incidence and Etiologies of Stroke during Pregnancy and Puerperium as Evidenced in Taiwanese Women

Background: Pregnancy is a known risk factor for stroke, but relatively few studies have been conducted in Asian populations to document the risk. This study aimed to analyze the incidence and etiologies of stroke occurring during pregnancy and puerperium in Taiwanese women. Methods: From 1984 to 2002, female patients 15 through 40 years of age with first-ever stroke during pregnancy or within 6 weeks of delivery were recruited. Stroke was classified as ischemic stroke (IS), cerebral venous thrombosis (CVT), intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH). The incidence, time of stroke onset (1st through 3rd trimester or puerperium), and etiologies of different stroke subtypes were analyzed. Results: Of 402 young female stroke patients, 49 had stroke during pregnancy and puerperium, including 16 with IS, 11 with CVT, 19 with ICH and 3 with SAH. After excluding referral patients, the incidences of pregnancy-related stroke were 46.2 (95% CI 30.7–69.5) per 100,000 pregnancies. 67% developed stroke in the 3rd trimester and puerperium, and 73% of CVT occurred in the puerperium period. Etiologies were well defined in 78% of patients. Eclampsia (37%) and arteriovenous malformation (26%) were the most important etiologies of ICH. For IS and CVT, rheumatic heart disease (44%) and coagulopathy (64%) were the major etiologies respectively. Conclusions: The incidence of stroke occurrence during pregnancy and puerperium in Taiwanese women is higher than that of Caucasian populations; the majority of strokes occurred in the 3rd trimester and puerperium, particularly CVT.

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.

Ultrasonographic Study and Long-term Follow-up of Takayasu's Arteritis

BACKGROUND AND PURPOSE Takayasus arteritis is an inflammatory vasculopathy involving the aorta and its major branches. Little information is available on the natural history and temporal profile of changes in the carotid vessels, the major vessels involved in Takayasus arteritis. Duplex ultrasonography may provide a reliable and efficient tool for the characterization and follow-up of the brachiocephalic vascular changes in Takayasus arteritis. METHODS Sixteen female patients fulfilling the clinical diagnostic criteria for Takayasus arteritis were studied. Mean age at onset was 23.6 years (SD = 6.0), and mean duration of follow-up was 17.1 years (SD = 11.9). The clinical features were analyzed. Only one patient had had a stroke. They had undergone at least one duplex scanning examination to evaluate the brachiocephalic vessels, including the extracranial carotid, vertebral, and subclavian arteries. Six patients underwent sequential duplex examination and long-term clinical follow-up. RESULTS All the studied patients had subclavian artery involvement, and 11 (69%) had common carotid artery involvement. The percentage of bilateral concomitant involvement was 100% in the common carotid artery and 33% in the subclavian artery. Homogeneous circumferential intima-media thickening was commonly seen in stenotic common carotid arteries (89%). Four patients had internal carotid artery involvement (all on the left side). In the serial duplex follow-up study, 2 of 6 patients had progressive vascular stenosis with concentric thickening, rather than longitudinal spreading, in the bilateral common carotid arteries. Left-side lesions were more prominent. Most were clinically stationary, despite severe stenosis or occlusion of the common carotid arteries. CONCLUSIONS The characteristic vascular lesions and progression changes in Takayasus arteritis detected by duplex ultrasonography are quite different from those seen in ordinary atherosclerosis. Homogeneous circumferential intima-media thickening of the common carotid arteries is a highly specific ultrasonographic finding in patients with Takayasus arteritis, particularly young women. Sequential duplex scanning showed vascular progression to be unpredictable and unrelated to medication in our patients. Further clinical investigations of vascular progression are warranted, and duplex scanning may provide a simple, safe, and accurate long-term means of follow-up.

Transcranial color-coded sonography helps differentiation between idiopathic Parkinson's disease and vascular parkinsonism

BackgroundRecently, transcranial color-coded sonography (TCCS) has been found to have a diagnostic value in patients with idiopathic Parkinsons disease (IPD), which displays increased hyperechogenicity at the substantia nigra (SN).ObjectiveTo use TCCS, to assess the difference in SN hyperechogenicity and intracranial hemodynamics among subjects with IPD, vascular parkinsonism (VP) and controls.MethodsEighty IPD and 30 VP patients, and 60 controls were recruited into this study. The hyperechogenicity area at the SN and midbrain were calculated by encircling the outer circumference from the ipsilateral temporal window, using TCCS in each subject. The hemodynamics of intracranial large arteries, including flow velocity and pulsatility index (PI), were also measured.ResultsThe presence of SN hyperechogenicity was significantly higher in the IPD patients than in the VP patients and controls (84% vs. 20% & 5%, respectively, p < 0.001). In IPD patients, the SN hyperechogenicity was correlated with the neurological severity and disease duration. Twenty-five (66.7%) VP patients had obvious vascular abnormality, as seen in TCCS study. The mean PI was significantly more elevated in the VP patients than those in the IPD patients and controls (all p < 0.05), but there was no significant difference of flow velocities among the VP, IPD patients and controls.ConclusionTCCS, combining B-mode imaging for SN echogenicity and trancranial Doppler for intracranial hemodynamics, is a useful diagnostic tool in the differentiation between IPD and VP. These findings also suggest that multiple subcortical vascular lesions may damage the basal ganglia and thalamocortical circuit and result in parkinsonism features in VP patients.

Symptomatic ostial vertebral artery stenosis treated with tubular coronary stents: clinical results and restenosis analysis.

Purpose: To evaluate the feasibility and safety of stent implantation to treat ostial vertebral artery stenosis. Method: Fifty-eight symptomatic patients (44 men; mean age 72 years, range 54 to 88) with 67 ostial vertebral artery lesions received 67 balloon-expandable coronary stents. Follow-up angiography was performed if restenosis was suspected or during later catheterization for other indications. Restenosis was defined as >50% diameter narrowing. Result: Technical success was 100%. Periprocedural neurological complications included 2 (3.4%) posterior and 1 (1.7%) anterior strokes. Other complications included 1 (1.7%) massive gastrointestinal hemorrhage requiring blood transfusion and endoscopic therapy, 1 (1.7%) femoral pseudoaneurysm requiring surgical repair, and 1 (1.7%) large shoulder hematoma secondary to a ruptured small branch of the thoracoacromial artery. Antiplatelet medication was discontinued in the ulcer patient, and the vertebral stent occluded at 8 months. At a mean follow-up of 31.3±17.1 months, 1 (1.7%) patient died after coronary bypass 2 months after stenting. One (1.7%) patient reported recurrent dizziness at 14 months and had angiographic evidence of in-stent restenosis. Angiographic evaluation of 32 (48%) lesions at a mean 11.0±9.6 months uncovered restenosis in 8 (25%) vessels, including the 2 cases noted above. Aside from these 2 patients, none of the other patients with restenosis were symptomatic. Multivariant Cox regression analysis showed reference vessel diameter as the only independent predictor of restenosis. Conclusion: Symptomatic ostial vertebral artery stenosis can be treated with relative safety using coronary techniques and equipment. Reference vessel diameter was the only predictor of restenosis in vertebral artery ostial stents.

Stroke in women of reproductive age: comparison between stroke related and unrelated to pregnancy

Pregnancy may increase the risk of stroke. However, few studies have compared strokes in women of reproductive age that occur in pregnancy or the puerperium (pregnancy-related stroke, PRS) with those unrelated to pregnancy. This study assesses risk factors and etiologies of stroke in these women based on relationship to pregnancy. From 1984 to 2002, all female patients 15 through 40 years of age with a first-ever stroke at National Taiwan University Hospital were included in this study. PRS was defined as patients who had stroke occurrence during pregnancy or within 6 weeks postpartum. Stroke was categorized as cerebral infarction (CI), cerebral hemorrhage (CH), or subarachnoid hemorrhage (SAH) and divided into subtype according to etiology. Risk factors and etiologies were compared for patients with PRS and stroke unrelated to pregnancy. We identified 49 patients with PRS, and 353 patients with stroke unrelated to pregnancy. There was no statistically significant difference in distribution of CI subtypes. Cerebral venous thrombosis (CVT) was more common in PRS than stroke unrelated to pregnancy (39% vs. 7%, P<0.001), and 73% of these cases occurred postpartum. Preeclampsia-eclampsia was an important cause of peripartum CH (37%), but not CI (4%). Among PRS cases, postpartum cerebral venous thrombosis and preeclampsia-eclampsia were the major causes of CI and CH, respectively.

Extracranial carotid atherosclerosis and vascular risk factors in different types of ischemic stroke in Taiwan.

The clinical patterns of stroke and the angiographic distribution of cerebral atherosclerosis in Chinese people are different from those in whites. Studies relating carotid atherosclerosis and vascular risk factors to various types of stroke in Chinese people are lacking. Methods Based on clinical information, we separated 367 stroke patients living in Taiwan into four subgroups: cortical infarction (CI), subcortical infarction (SCI), vertebrobasilar artery infarction (VBAI), and cardioembolic infarction (CEI). We assessed the extent and severity of extracranial carotid artery atherosclerosis in different types of ischemic stroke using duplex ultrasonography. Vascular risk factors and carotid atherosclerosis were then correlated with each subgroup of ischemic stroke. Results Our data revealed that 32% of the CI subgroup, 3% of the SCI subgroup, 7% of the VBAI subgroup, and 21% of the CEI subgroup possessed severe carotid stenosis (≥50% stenosis or occlusion). The extent of atherosclerosis of extracranial carotid arteries, measured by plaque score, was also more severe in the CI subgroup than in the other subgroups. Diabetes mellitus was more frequent in the CI subgroup. Cardiomegaly and left ventricular hypertrophy were more commonly seen in the CEI subgroup. The VBAI subgroup was younger than the other subgroups. There were no differences in hypertension, prior stroke, alcohol intake, or serum levels of glucose, uric acid, hematocrit, lipids, and lipoproteins among the subgroups. Conclusions Of the Chinese patients living in Taiwan, the extent and severity of extracranial carotid artery atherosclerosis were more prominent in patients with CI than in patients with other types of ischemic stroke. In Chinese patients with CI, severe carotid stenosis is not uncommon; in Chinese patients with SCI, however, the frequency of carotid stenosis is quite low.

Early and intensive rehabilitation predicts good functional outcomes in patients admitted to the stroke intensive care unit

Purpose. Earlier and more intense rehabilitation benefit stroke patients. Yet, studies have caution intensive therapy during acute brain injury. This study examined the rehabilitation commencement time and intensity as predictors of functional outcomes in acute stroke patients admitted to the stroke intensive care unit (ICU). Method. Sociodemographic, medical, rehabilitative and functional data were collected on 154 acute stroke patients. Regression analyses were used to identify predictors for the basic activities of daily living (Barthel Index, BI) and the walking ability at discharge. Result. Rehabilitation commencement time and intensity significantly predicted the BI score at discharge after adjusting for initial severity (National Institute of Health Stroke Scale, NIHSS) and age (p < 0.05). For the walking function at discharge, only the rehabilitation intensity was a significant predictor after adjusting for initial severity and age (p < 0.05). Furthermore, with increasing rehabilitation intensity, patients with severe stroke benefited more than those with moderate stroke. Conclusion. Rehabilitation commencement time and intensity, after adjusting for admission functional status and severity of stroke, remained to be important predictors of stroke functional outcomes. This study supported the recommendation to commence rehabilitation early and intensively and provided evidence that this claim can be extended to acute stroke patients admitted to an ICU.

Dose-Response Relation Between Neuromuscular Electrical Stimulation and Upper-Extremity Function in Patients With Stroke

Background and Purpose— The purpose of our study was to investigate the effects of different doses of neuromuscular electrical stimulation (NMES) on upper-extremity function in acute stroke patients with severe motor deficit. Methods— Sixty-six acute stroke patients were randomized to 3 groups: high NMES, low NMES, or control. The low-NMES group received 30 minutes of stimulation per day, and the high-NMES group received 60 minutes per day, for 4 weeks. The Fugl-Meyer Motor Assessment Scale, Action Research Arm Test, and Motor Activity Log were used to assess the patients at baseline, 4 weeks, and 12 weeks post baseline (follow-up). Results— Both NMES groups showed significant improvement on Fugl-Meyer Motor Assessment and Action Research Arm Test scales compared with the control group at week 4 and follow-up. The high-NMES group showed treatment effects similar to those of the low-NMES group. Conclusions— Higher and lower doses of NMES led to similar improvements in motor function. A minimum of 10 hours of NMES in combination with regular rehabilitation may improve recovery of arm function in stroke patients during the acute stage.