PubMed Health⌕ Search

Biomedical subjects

Wan-Leong Chan

Publications and source records attributed to Wan-Leong Chan.

7 recordsLinked to original sources

Is hyperuricemia another facet of the metabolic syndrome?

BACKGROUND: Hyperuricemia is commonly associated with obesity, glucose intolerance, hypertension, dyslipidemia, and atherosclerotic cardiovascular disease. The resemblance of the metabolic syndrome and hyperuricemia has led to the suggestion that hyperuricemia is a part of the metabolic syndrome. The purpose of this study is to examine the contribution of uric acid (UA) as an additional component of the metabolic syndrome in middle-aged men. METHODS: In total, 393 male participants, aged 45-60 years, were recruited from a professional health evaluation program. Anthropometric measurements and blood pressure (BP) were taken after an overnight fast. Fasting blood samples were collected for the measurements of glucose, UA, and lipid profile. Logistic regression models were fitted to examine the relationship between UA and the diagnosis of metabolic syndrome. Factor analysis was performed to explore the relationship between UA and the components of the metabolic syndrome. RESULTS: The diagnosis of the metabolic syndrome was significantly associated with waist circumference (WC), glucose, triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), systolic BP, and liver enzyme levels, but not associated with UA levels. The sensitivity of hyperuricemia (serum UA > or = 7.0 mg/dL) for the diagnosis of the metabolic syndrome was 58.0% and the specificity was 55.3%. In factor analysis, UA aggregated with body mass index, WC, glucose, log TG, and HDL-C as a metabolic factor. Systolic and diastolic BP were loaded on a second factor separately. The model loaded with UA explained a similar proportion of the total variance (56.9%), as did the model loaded without UA (62.5%). CONCLUSION: Our results suggest that the contribution of UA as an additional component of the syndrome seems to be insignificant. We propose that hyperuricemia might not be an important facet for the understanding of the underlying structure of the metabolic syndrome.

Alanine Transaminase↗

Double-barrel coronary artery dissection.

Coronary artery dissection is a common occurrence after percutaneous transluminal coronary angioplasty (PTCA). However, we report herein a rare case of double-barrel coronary artery dissection occurring 1 year after PTCA for stenosis in the left circumflex coronary artery. The case history and angiographic findings are reported, and relevant literature is reviewed.

Aged↗

Impairment of coronary microvascular function in patients with neurally mediated syncope.

Recent evidence suggests that myocardial ischemia may occur in patients with neurally mediated syncope and normal coronary angiograms. This study was conducted to evaluate if coronary microvascular function is impaired in such patients. Coronary hemodynamic studies and head-up tilt table tests (HUTs) were performed on 30 consecutive patients with normal coronary angiograms and recurrent syncope. Another ten subjects with atypical chest pain and no evidence of myocardial ischemia or syncope served as a control. Great cardiac vein flow (GCVF) and coronary sinus flow (CSF) were measured by the thermodilution method at baseline and after dipyridamole infusion (0.56 mg/kg i.v. for 4 minutes). Coronary flow reserve (CFR), derived from CSF and GCVF, was significantly lower in the 15 patients with positive HUT than in the other 15 patients with negative HUT (1.75 +/- 0.48 vs 2.64 +/- 0.8, P < 0.01 and 2.29 +/- 0.45 vs 3.07 +/- 0.63, P < 0.01, respectively). Ischemic-like ECG was noted during treadmill exercise test in 40% of the former and in 7% of the latter group (P = 0.01). There was no significant difference in CFR between patients with negative HUT and control subjects. Coronary microvascular function was impaired in syncopal patients with positive HUT and relatively preserved in those with negative HUT, suggesting the possible linkage between coronary microvascular dysfunction and the development of neurally mediated syncope.

Case-Control Studies↗

Congenital absence of the left circumflex coronary artery.

We report a rare case of congenital coronary artery anomaly with recurrent chest pain. A 44-year-old Taiwanese female patient presented with exertional chest pain that had lasted for 2 years. An electrocardiogram showed right axis deviation and an rS pattern in leads I and aVL, and an exercise stress test was inconclusive. A thallium-201 myocardial perfusion study revealed perfusion defects in the septal and inferior walls which normalized in the delayed imaging. Coronary angiography revealed the absence of a left circumflex coronary artery and a superdominant right coronary artery with terminal branches supplying the left ventricular inferior and posterolateral walls. An aortogram revealed no evidence of the existence of a left circumflex coronary artery. Administration of nitrates and calcium antagonists could not ameliorate her symptoms, but she remained stable during ordinary activity. In young premenopausal female patients who present with symptoms suggestive of angina pectoris and a positive stress test, congenital anomaly of the coronary artery should be considered and an angiographic study should be performed.

Adult↗

Clinical characteristics and endoscopic findings associated with Blastocystis hominis in healthy adults.

Ninety-nine individuals with stools positive for Blastocystis hominis but negative for other parasites were identified from medical records of healthy adults who had received a physical examination at Taipei Veterans General Hospital from November 2000 to October 2002. The medical records of these 99 positive cases and 193 randomly selected controls, matched for age, sex, and date of examination, were retrospectively reviewed. The pathogenicity of B. hominis could not be demonstrated due to a lack of association with the development of gastrointestinal symptoms or pathologic findings on endoscopic examination. Multivariate analyses revealed that chronic hepatitis B infection was a predisposing condition to the acquisition of B. hominis (odd ratio = 2.848, 95% confidence interval = 1.299-6.242, P = 0.009), and concentration of urate was significantly lower in B. hominis-positive individuals (mean +/- SD = 361.64 +/- 87.44 versus 392.57 +/- 93.38 micromol/L; P = 0.009). Among the 64 individuals who underwent gastric biopsy, Helicobacter pylori was found more frequently in the individuals harboring B. hominis (19 of 26 versus 15 of 38; P = 0.017).

Animals↗

Clinical and angiographic determinants of adverse cardiac events in patients with stent restenosis.

Patients with angiographically proven stent restenoses do not necessarily develop adverse cardiac events. Which clinical, procedural, or angiographic parameters relate to the development of adverse cardiac events among these patients has not been determined. This study included 155 patients (167 stented lesions) with angiographically proven restenosis (> or = 50% diameter stenosis) within the stent or at its margins in routine follow-up angiograms that was obtained at 6.5 +/- 3.6 months after successful stenting. Thirty-six patients (22%) had adverse cardiac events (including unstable angina necessitating target lesion revascularization, acute myocardial infarction, or cardiac death) during follow-up and 119 patients (78%) were event-free. These two groups of patients were compared to determine the parameters related to adverse cardiac events. Univariate determinants of adverse events included hypertension (P = 0.023), unstable angina at initial presentation (P = 0.002), target lesion in proximal left anterior descending artery (P = 0.041), TIMI grade 0-2 flow in follow-up angiograms (p < 0.001), impaired left ventricular function at follow-up (P = 0.002), follow-up minimal lumen diameter < or = 0.6 mm (P = 0.003), follow-up diameter stenosis > 75% (P = 0.005), late loss > 2 mm (P = 0.01), and loss index > 1.127 (P < 0.001). Multivariate analysis demonstrated hypertension (odds ratio, OR, = 3.6; P = 0.019), unstable angina at initial presentation (OR = 2.6; P = 0.007), TIMI grade 0-2 flow at follow-up (OR = 2.8; P = 0.05), impaired LV function at follow-up (OR = 4.2; P = 0.004), and loss index > 1.127 (OR = 3.6; P = 0.017) as independent risk factors for adverse cardiac events. Classification and regression tree analysis identified loss index > 1.127 and impaired LV function as the two strongest determinant of adverse cardiac event. Therefore, hypertensive patients whose initial clinical presentation were unstable angina should be managed carefully to optimize the angiographic results and, most importantly, followed up more closely for development of impaired LV function after coronary stenting in order to prevent the occurrence of adverse cardiac event at follow-up.

Aged↗