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Shan-Jin Ryu

Publications and source records attributed to Shan-Jin Ryu.

7 recordsLinked to original sources
PubMed2007

Carotid ultrasound criteria for detecting intracranial carotid stenosis.

BACKGROUND/AIMS: This study attempted to establish carotid ultrasound criteria for identifying stenosis of the intracranial internal carotid artery (ICA) and middle cerebral artery (MCA). METHODS: Two hundred and fifty-five patients were enrolled. Ultrasound measurements for common carotid artery (CCA) and ICA were as follows: flow volume (FV), peak systolic velocity (PSV), end-diastolic velocity (EDV), pulsatility index (PI) and resistance index (RI). The sensitivity and specificity of the ultrasound criteria for determining intracranial ICA or MCA>or=50% stenosis were calculated. RESULTS: The criteria identified for detecting intracranial ICA>or=50% stenosis were ICA FV<159 ml/min, ICA PSV<33 cm/s and CCA PSV<42 cm/s. When ICA PSV<33 cm/s was combined with CCA PSV<42 cm/s, sensitivity increased to 82%, with 91% specificity. The criteria identified for detecting MCA>or=50% stenosis were CCA FV<285 ml/min, ICA FV<179 ml/min, ICA PSV<33 cm/s, >35% reduction in FV in the CCA, >40% reduction in FV in ICA, and >35% reduction in PSV in ICA. When these criteria were combined, sensitivity increased to 69%, with 85% specificity. CONCLUSION: This study demonstrated that ultrasound criteria are sensitive and specific for detecting intracranial ICA and MCA significant obstruction.

Angiography↗
PubMed2006

Dose titration to reduce dipyridamole-related headache.

BACKGROUND: Combination of low-dose aspirin and modified-release dipyridamole (ASA+MR-DP) provides a significantly increased benefit in stroke prevention over aspirin alone. However, headaches were reported in more patients receiving dipyridamole-containing agents than in those receiving placebo. We undertook a randomized, double-blind, placebo-controlled trial to evaluate which dosing regimens of ASA+MR-DP have better tolerance. METHODS: This trial randomized 146 patients with a history of ischemic cerebrovascular disease into three groups: placebo (days 1-28), reduced dose (placebo on days 1-4, ASA+MR-DP once daily before bed during days 5-14, and b.i.d. on days 15-28), and regular dose (placebo on days 1-4, and ASA+MR-DP b.i.d. on days 5-28). Using Chinese diary card, headache was assessed as mean cumulated headache (Sigma frequency x intensity/occurrence days x study days) over the study period, and was graded 0-4 according to Cancer Therapy Evaluation Program, Common Toxicity Criteria, Version 2.0. RESULTS: Intent-to-treat patients after randomization was 46 in placebo group, 45, reduced dose, and 49, regular dose. Among commonly reported adverse effects, headache of any grade occurred significantly more in the regular dose group (38.8%), as compared to the other two groups (p < 0.05). Mean cumulated headache was higher (p < 0.05) in the regular dose group than in the reduced group during days 5-14. Of 27 patients who dropped out, 15 (55.6%) were due to headache, which was substantially more in regular dose (8, 53.3%), though the difference was statistically insignificant. CONCLUSIONS: Initial reduced dose treatment with ASA+MR-DP may cause fewer headaches than regular dosing, and seems better tolerated by those susceptible to phosphodiesterase inhibitor-induced headache.

Aged↗
PubMed2006

Concurrent moyamoya disease and Graves' thyrotoxicosis: case report and literature review.

Coexistence of thyrotoxicosis and moyamoya disease is extremely rare. A 23-year-old woman who had a history of migraine, suffered from frequent right carotid transient ischemic attacks, followed by an ischemic stroke after taking ergotamine for migraine. Magnetic resonance angiography revealed a tubular stenosis of the right internal carotid artery (ICA) and bilateral strictures of the supraclinoid segments of the ICAs. A concomitant thyrotoxicosis was found. A second stroke occurred three weeks later, when the dosage of antithyroid medication was increased and phenylpropanolamine-containing cold remedies were taken. Moyamoya disease was confirmed by cerebral angiography which showed irregular tubular stenosis of the right cervical ICA just above the bifurcation and nearly complete occlusion of bilateral supraclinoid ICAs with collateral flows from posterior circulation. The complexity of the cerebral hemodynamics of this patient is discussed.

Adult↗
PubMed2006

Risk factors of carotid stenosis in first-ever ischemic stroke in Taiwan: a hospital-based study.

OBJECTIVE: The aim of this study is to identify the risk factors of extracranial carotid atherosclerosis in patients with first-ever ischemic stroke. MATERIAL AND METHODS: A total of 541 consecutive first-ever ischemic stroke patients were enrolled in the present study. We examined clinical and laboratory factors that were potentially relevant to extracranial carotid artery atherosclerosis. The degree of carotid stenosis was diagnosed based on B-mode ultrasonography. RESULTS: The sample contained 325 men and 216 women. Among these patients, 80% had a < 50% carotid stenosis and 20% had a > or = 50% carotid stenosis. Multiple logistic regression analysis revealed that age (odds ratio = 2.15, 95% CI = 1.06-1.11, P < 0.001) and smoking (odds ratio = 1.52, 95% CI = 1.17-3.54, P = 0.012) were significantly associated with > or = 50% carotid stenosis. CONCLUSIONS: In the present study, age and smoking are found to be the independent risk factors for carotid atherosclerosis. The identification of these risk factors may improve our knowledge in the primary prevention of ischemic stroke in Taiwan.

Adult↗
PubMed2002

Carotid artery stenosis in ischemic stroke patients with nonvalvular atrial fibrillation.

PURPOSE: To study the prevalence, severity and clinical relevance of carotid atherosclerosis in ischemic stroke patients with nonvalvular atrial fibrillation (NVAF). MATERIAL AND METHODS: We reviewed carotid duplex sonography, computed tomography (CT) and clinical features in 103 consecutive ischemic stroke patients with NVAF. Both sonography and CT were performed within 3-7 days after stroke. There were 64 men and 39 women with a mean age at stroke onset of 69 years. RESULTS: High-grade (> or =50%) stenosis of the extracranial carotid artery was detected in 25 patients (24.3%), including 11 patients (10.6%) with internal carotid artery (ICA) occlusion. In 15 (66.7%) of the patients who had high-grade carotid stenosis, the lesion was ipsilateral to the infarct, including 8 ICA occlusions. Patients with high-grade stenosis smoked more cigarettes (p < 0.05) and had more peripheral vascular diseases (p < 0.05). Besides NVAF, all patients had more than one vascular risk factor. The clinical presentations (transient ischemic attacks, minor or major strokes) showed no significant difference between the groups of <50% and > or =50% stenosis. Clinical outcome was worse (dead and totally dependent in daily activities) in the group of high-grade stenosis (p < 0.05). Patients with high-grade carotid stenosis showed more cortical infarcts on cerebral CT (p < 0.01). Six out of 7 patients with a hemorrhagic transformation on the initial cerebral CT were in the low-grade carotid stenosis group, though this was statistically insignificant. CONCLUSIONS: Ischemic stroke with NVAF is not always cardiogenic. High-grade stenosis of the extracranial carotid artery is found in one fourth of ischemic stroke patients with NVAF and is related to more cortical infarction and worse clinical outcome. We speculate that ischemic stroke patients with NVAF who have high-grade carotid stenosis are less likely to develop hemorrhagic infarct. The pathogenesis of cerebral infarction and the therapeutic strategy in this clinical condition are complicated by the coexistence of carotid arterial lesions and cardiac disease.

Aged↗
PubMedDate not supplied

Cerebral hemodynamic responses to betel chewing: a Doppler study.

We sought to evaluate cerebral hemodynamic responses to betel chewing. Thirty healthy male volunteers (mean age = 35 years), ten new chewers, ten occasional chewers, and ten chronic chewers were included in this study. We used carotid duplex sonography and transcranial Doppler to measure the flow velocities and flow volume (FV) of the common carotid (CCA), internal carotid (ICA), external carotid (ECA) arteries, and the flow velocity of middle cerebral artery (MCA). Blood pressure (BP) and heart rate (HR) were recorded simultaneously. All subjects were asked to chew fruit-flavored chewing gum for 10 minutes. Blood flows of the above vessels were measured four times at baseline and at the 2nd, 6th, and 12th minute after chewing. A repeated study was followed in the same subject but substituted with betel nut. Chronic chewers had delayed onset time and shortened vanishing time of facial-flushing sensation. Systolic and diastolic BPs were mildly elevated during gum chewing (p = 0.008 and 0.015, respectively), whereas diastolic BP was dropped during betel chewing (p = 0.008). Heart rate increased prominently during betel chewing (p < 0.0001), especially in new and occasional chewers. The peak systolic, end diastolic velocities, and FV in ECA and CCA increased significantly during betel chewing (p < 0.0001). The blood flows in the ICA and MCA had no significant changes during gum or betel chewing. Betel chewing has a central sympathetic effect resulting in accelerated HR, increased blood flows in ECA and CCA, but has a peripheral cholinergic effect resulting in a drop of diastolic BP. Intracranial cerebral hemodynamics is not affected during betel chewing. The inotropic and chronotropic effect to the heart from betel chewing is probably an unfavorable risk for patients with ischemic heart disease.

Adult↗