K.S. Woo

Hyperhomocyst(e)inemia Is a Risk Factor for Arterial Endothelial Dysfunction in Humans

BACKGROUND Hyperhomocyst(e)inemia is associated with premature peripheral vascular, cerebrovascular, and coronary artery disease. Because homocysteine has been found to be damaging to endothelial cells in animal and cell culture studies, we evaluated the association between hyperhomocysteinemia and arterial endothelial dysfunction (a marker of early atherosclerosis) in asymptomatic adult subjects. METHODS AND RESULTS Using high-resolution ultrasound, we measured endothelium-dependent flow-mediated dilation (EDD) and endothelium-independent nitroglycerin-induced dilation (GTN) of the brachial artery in 14 prospectively defined hyperhomocysteinemic (mean plasma homocysteine, 34.8+/-8.5 micromol/L), nonsmoking, healthy subjects aged 53+/-9 years and 14 control subjects with low plasma homocysteine levels (9.9+/-3.2 micromol/L). The two groups were well matched for age; sex; body mass index; blood pressure, blood cholesterol, folate, and vitamin B12 levels; and vessel diameter. EDD was significantly lower in hyperhomocysteinemic subjects (6.5+/-1.7%) than in subjects with low homocysteine levels (10.8+/-1.7%) (P<.001). GTN responses were similar in the two subject groups (P=.90). Multivariate analysis confirmed homocysteine level as the strongest predictor for impaired EDD, independent of age, sex, body mass index, or blood pressure, folate, vitamin B12, and cholesterol levels. CONCLUSIONS Hyperhomocysteinemia is an independent risk factor for arterial endothelial dysfunction in healthy middle-aged adults.

Overweight in children is associated with arterial endothelial dysfunction and intima-media thickening.

OBJECTIVE: We sought to study arterial endothelial function and carotid intima-media thickness (IMT), both early markers of atherosclerosis, in overweight compared to normal children.DESIGN: Case–control comparison.SUBJECTS: A total of 36 asymptomatic overweight children (body mass index (BMI)>23; mean 25±3) aged 9–12 y and 36 age- and gender-matched nonobese healthy children (BMI<21) from a school community.MEASUREMENTS: The key parameters were: BMI, arterial endothelial function (ultrasound-derived endothelium-dependent dilation) and carotid artery IMT. The secondary parameters measured included body fat content, waist–hip ratio (WHR), blood pressures, blood lipids, insulin and glucose.RESULTS: The two groups were well matched for blood pressures, cholesterol and glucose levels, but BMI (P<0.0001), body fat (P=0.001), WHR (P<0.05), fasting blood insulin (P=0.001) and triglyceride levels (P<0.05) were higher in obese children. Overweight was associated with impaired arterial endothelial function (6.6±2.3 vs 9.7±3.0%, P<0.0001) and increased carotid IMT (0.49±0.04 mm vs 0.45±0.04 mm, P=0.006). The degree of endothelial dysfunction correlated with BMI (P<0.003) on multivariate analysis.CONCLUSION: Obesity, even of mild-to-moderate degree, is independently associated with abnormal arterial function and structure in otherwise healthy young children.

Chemistry and Biological Activities of Caffeic Acid Derivatives from Salvia miltiorrhiza

Caffeic acid (3,4-dihydroxycinnamic acid), one of the most common phenolic acids, frequently occurs in fruits, grains and dietary supplements for human consumption as simple esters with quinic acid or saccharides, and are also found in traditional Chinese herbs. Caffeic acid derivatives occur as major water-soluble components of Salvia miltiorrhiza, including caffeic acid monomers and a wide variety of oligomers. This review provides up-to-date coverage of this class of phenolic acids in regard to structural classification, natural resources, chemical and biosyntheses, analytical methods and biological activities including antioxidant, anti-ischemia reperfusion, anti-thrombosis, anti-hypertension, anti-fibrosis, antivirus and antitumor properties. Special attention is paid to both structural classification and biological activities. The structural diversity and the pronounced biological activities encountered in the caffeic acid derivatives of S. miltiorrhiza indicate that this class of compounds is worthy of further studies that may lead to new drug discovery.

Right Ventricular Diastolic Dysfunction in Heart Failure

BACKGROUND Left ventricular (LV) diastolic dysfunction is common in heart failure and is an important predictor of prognosis and mortality. Less attention has been paid to right ventricular (RV) diastolic function. In this study, we compared RV diastolic function in a large cohort of patients with heart failure (HF) with two groups: patients with pulmonary hypertension and normal LV function (the PHT group) and normal subjects. METHODS AND RESULTS Transtricuspid and pulmonary artery flow were assessed by two-dimensional Doppler echocardiography at maximum inspiration and expiration in 185 subjects: 114 symptomatic HF patients (ejection fraction < 0.5), 31 PHT patients (pulmonary artery systolic pressure > 40 mm Hg), and 40 normal subjects. A subset was matched for age and heart rate. The results showed a high prevalence of RV diastolic abnormalities: HF patients had lower tricuspid E-A ratios, lower peak E-wave velocity, and prolonged RV isovolumic relaxation time (all P< .0001). Tricuspid E-wave deceleration time was significantly shorter only in those who had an LV restrictive filling pattern. The PHT group had similar findings. Compared with a normal range, more than half of the patients had lower tricuspid E-A ratios (HF, 55%; PHT, 69%), and 61% of HF and 58% of PHT patients had a prolonged RV isovolumic relaxation time. In the PHT group, RV diastolic parameters (E-wave deceleration time, E-A ratio, and isovolumic relaxation time) correlated significantly with pulmonary artery systolic pressure (P< .05). In the HF group, however, only tricuspid E-wave deceleration time correlated significantly with pulmonary artery systolic pressure, and HF patients with normal pulmonary artery systolic pressures had significantly lower tricuspid E-A ratios and prolonged RV isovolumic relaxation times compared with normal subjects. A close correlation existed between individual RV and LV diastolic parameters, suggesting that LV diastolic dysfunction may directly affect RV function, but there was no relation between LV size or systolic function and RV diastolic dysfunction. CONCLUSIONS RV diastolic function is frequently abnormal in HF patients, and this is not related to elevated pulmonary artery systolic pressure alone, although high pulmonary artery pressure by itself also is associated with impaired RV diastolic function. Assessment of the role of right ventricular diastolic function in determining the symptoms and prognosis of heart failure is warranted.

Carotid artery intima media thickness, plaque and framingham cardiovascular score in Asia, Africa/Middle East and Latin America: the PARC-AALA Study

ObjectiveThe PARC-AALA (Paroi artérielle et Risque Cardiovasculaire in Asia Africa/ Middle East and Latin America) study was designed to evaluate the correlation between intima-media thickness of the common carotid artery (CCAIMT), carotid plaque and absolute cardiovascular risk in a multi-ethnic population.MethodsAn international, cross-sectional, study including 79 centres from 21 countries in Asia, Africa, the Middle East and Latin America. Two thousand three hundred and twenty-eight subjects, meeting all inclusion criteria, were stratified by risk factors groups (no modifiable factor or at least both uncontrolled hypertension and hypercholesterolemia). CCAIMT, presence of plaque and cardiovascular risk factors were assessed for each individual.ResultsSome intergeographical characteristics in demographics, and risk factors were found accompanying early atherosclerosis marker differences. In Asia where the subjects were at lower risk, the mean CCAIMT was 4% lower than in Africa/Middle East and Latin America. On multiple linear regression analysis CCAIMT and carotid plaque were independently associated with increased Framingham cardiovascular score (FCS) without heterogeneity across geographic regions. CCAIMT and carotid plaque explained roughly 20% of the FCS in both genders.ConclusionThe PARC-AALA study confirms the correlation between CCAIMT and FCS in three different populations. Intima-media thickness (IMT) and plaque evaluation may represent a complementary predictive tool for detection of cardiovascular disease in individuals.

Carotid Intima Media Thickness Predicts Cardiovascular Diseases in Chinese Predialysis Patients with Chronic Kidney Disease

Patients with chronic kidney disease (CKD) have a high risk for cardiovascular disease. Ultrasound measurements of the intima media thickness (IMT) in the carotid arteries is a strong predictor for cardiovascular events in the general population and dialysis patients. However, it is unclear whether carotid IMT is useful for the prediction of cardiovascular events in predialysis patients with CKD. The prediction power of carotid ultrasonography for cardiovascular event, rate of renal function decline, and all-cause mortality was tested in a cohort of 203 Chinese patients with stages 3 to 4 CKD. The average IMT was 0.808 +/- 0.196 mm; 121 (59.6%) patients had atherosclerotic plaques visualized. IMT correlated with patient age (r = 0.373, P < 0.001), serum LDL level (r = 0.164, P = 0.021), Charlsons comorbidity score (r = 0.260, P < 0.001), and serum C-reactive protein (r = 0.279, P < 0.001). Carotid IMT was significantly higher in patients with diabetes than in those without diabetes (0.930 +/- 0.254 versus 0.794 +/- 0.184; P = 0.002). At 48 mo, the cardiovascular event-free survival was 94.4, 89.8, 77.7, and 65.9% for IMT quartiles I, II, III, and IV, respectively (log rank test, P = 0.006). By multivariate analysis with the Cox proportional hazard model, each higher quartile of IMT conferred 41.6% (95% confidence interval 6.4 to 88.4%; P = 0.017) excess hazard for developing cardiovascular event. The actuarial survival at 48 mo was 96.3, 98.0, 95.7, and 85.7% for IMT quartiles I, II, III and IV, respectively (log rank test, P = 0.127), and the difference was not statistically significant after Cox proportional hazard model to adjust for confounders. Carotid IMT did not correlate with the rate of renal function decline in these patients. Carotid IMT is a strong predictor of cardiovascular disease in Chinese predialysis patients and may be usefully applied for risk stratification in this group of patients.

Radiofrequency Ablation Versus Antiarrhythmic Medication for Treatment of Ventricular Premature Beats From the Right Ventricular Outflow Tract Prospective Randomized Study

Background—The purpose of this study was to compare the efficacy of radiofrequency catheter ablation (RFCA) versus antiarrhythmic drugs (AADs) for treatment of patients with frequent ventricular premature beats (VPBs) originating from the right ventricular outflow tract (RVOT). Methods and Results—A total of 330 eligible patients were included in the study and were randomly assigned to RFCA or AADs group. The absolute number and the burden of VPBs on 12-lead Holter monitors were measured at baseline and at 1st, 3rd, 6th, and 12th months after randomization. Left ventricular eject fraction was evaluated by transthoracic echocardiogram at baseline and at 3 and 6 months after randomization. During the 1-year follow-up period, VPB recurrence was significantly lower in patients randomized to RFCA group (32 patients, 19.4%) versus AADs group (146 patients, 88.6%; P<0.001, log-rank test). In a Poisson generalized estimating equations (GEE) regression model, RFCA was associated with a greater decrease in the burden of VPBs (incidence rate ratio 0.105; 95% confidence intervals [0.104–0.105]; P<0.001) compared with AADs. In a liner GEE model, the left ventricular eject fraction had a tendency to increase after the treatment in both groups (coefficient, 0.584; 95% confidence intervals [0.467–0.702]; P<0.001). In a Cox proportional model, the QS morphology in lead I was the only predictor of VPB recurrence free for catheter ablation (hazards ratio, 0.154; 95% confidence intervals [0.044–0.543]; P=0.004). Conclusions—Catheter ablation is more efficacious than AADs for preventing VPB recurrence in patients with frequent VPBs originating from the RVOT. QS morphology in lead I was associated with better outcome after ablation.

Epidemiology of coronary arterial disease in the Chinese

The occurrence of coronary arterial disease and, in particular, acute myocardial infarction in three Chinese communities, namely Hong Kong, Taiwan and China, was reviewed by using a multifaceted approach. Both the prevalence and death incidence of coronary arterial disease or acute myocardial infarction were much lower than those in most western countries: in these three places, the prevalence of coronary arterial disease, the incidence of mortality from coronary arterial disease, the incidence of acute myocardial infarction and the mortality from acute myocardial infarction were roughly one-eighth to one-quarter of the average western figures. While the prevalence and mortality figures have been declining in most affluent western countries, they have been increasing in these three large Chinese communities with 1200 million people. The implication of this increasing trend should certainly deserve more consideration in future planning in these regions. While aging is a contributing factor to such a trend, more work is required to delineate and assess the relative significance of the changes in the socioeconomic and coronary risk factors in the process of modernisation.

The Mediterranean score of dietary habits in Chinese populations in four different geographical areas.

Objective: To compare the dietary intake of Chinese people living in Pan Yu, Hong Kong, San Francisco and Sydney with respect to cardiovascular health, using the Mediterranean diet score, examining the effects of age, gender, urbanization and acculturation on the diet score.Subjects: A total of 500 men and 510 women in Hong Kong were recruited as a territory-wide stratified random sample. Subjects were recruited in response to local advertisements for the other three sites: Pan Yu, 58 men, 95 women; San Francisco, 166 men, 192 women; Sydney, 95 men, 73 women.Method: Food-frequency questionnaire over a 7 week period. A high/healthy score was taken as ≥4 for men and ≥3 for women, representing a dietary pattern beneficial for cardiovascular health.Results: In Hong Kong, more women in the middle age group (35–54) had a high score than other age groups, and overall more women had high scores than men. In comparing the four geographical regions, Pan Yu had the highest number of subjects with high score, and Hong Kong had the lowest. With the exception of the younger population and men in Hong Kong, the percentage of the population with a high score in all sites is greater than among elderly Greeks consuming a more traditional heart-healthy Mediterranean diet.Conclusion: Considerable variations in Chinese dietary patterns exist with respect to age, gender and geographic location. Overall, the Chinese diet is comparable to the Mediterranean diet and may be expected to have similar health benefits that have been documented for the traditional Mediterranean diet.European Journal of Clinical Nutrition (2001) 55, 215–220

The prevalence and pattern of pulmonary thromboembolism in the Chinese in Hong-Kong

The prevalence and clinical pattern of pulmonary thromboembolism was studied by a multifaceted approach. This documented the occurrence of pulmonary thromboembolism among the Chinese and confirmed an increasing incidence in Hong Kong, although comparatively it was still much lower (about one-tenth) than that found in western communities. Their clinical pattern, regarding presentation, risk factors, clinical features and response to thrombolytic therapy, conformed well with those reported in the west, but perhaps appeared in a milder form. The strong association of pulmonary thromboembolism with varicose veins and immobilisation would appeal for recommending routine heparinisation in Chinese patients having these combinations. Our findings will stimulate more interest in the comparative study of the haematological profile and the ethnic particulars of the Chinese.