The association of apolipoprotein B and low density lipoprotein with cardiovascular risk factors in the Thai population.

BACKGROUND: Although direct and calculated low density lipoprotein cholesterol (LDL-cholesterol) has been widely used as an important predictor for cardiovascular risk, many studies have shown that apolipoprotein B (apo B) may be a more important lipoprotein marker. MATERIAL AND METHOD: We performed a cross-sectional study on 191 volunteers who were Shinawatra employees during their annual physical check up. The following cardiovascular risk factors were recorded or measured: direct and calculated LDL, apo B, gender age, total cholesterol, triglyceride, HDL-cholesterol (HDL), calculated LDL, fasting plasma glucose (FPG), systolic and diastolic blood pressure, smoking status, body mass index (BMI), waist circumference, and waist-hip ratio (WHR). Apo B, direct LDL and calculated LDL levels were tested for their associations with other potential cardiovascular risk factors. RESULTS: There were a total of 76 men and 115 women with an average age of 28.8 +/- 5.4 years. Male gender, cigarette smoking, high cholesterol, high triglyceride, high fasting plasma glucose, hypertension, high WHR and high BMI were associated with increased apo B level. Only male gender and high cholesterol were associated with increased calculated and direct LDL level. The association of direct and calculated LDL-cholesterol level with cardiovascular risk factors appears to be similar. CONCLUSION: We demonstrated that apo B level correlates more with other cardiovascular risk factors compared to direct and calculated LDL-cholesterol. The clinical relevance of this finding needs to be explored in large-scale studies.

Reference centile chart for transverse cerebellar diameter (TCD) in Thai fetuses throughout gestation.

Objective: To create a reference centile chart for transverse cerebellar diameter in Thai fetuses throughout gestation. Methods: A total of 780 pregnant women between 13-40 weeks gestation, who attended at the antenatal clinic at Siriraj Hospital, Mahidol University, Bangkok, were recruited. Each fetus was measured only once for the purpose of this study. The mean and fitted centiles were estimated at each week of gestation using linear regression modeling. Results: A total of 752 fetuses were measured for fetal transverse cerebellar diameter. Linear regression models were fitted to estimate the meant 95% confidence interval for transverse cerebellar diameter at each gestational age. The centile chart of this parameter was also presented. Conclusion: Reference centile chart for fetal transverse cerebellar diameter of Thai fetuses was created.

Accuracy of international normalized ratio determined by portable venous-blood coagulation monitor versus a central laboratory.

BACKGROUND: The CoaguChek is a portable monitor unit for measuring the international normalized ratio (INR). The purpose of the study was to evaluate the accuracy of a portable prothrombin time (PT) monitor (CoaguChek, Roche Diagnostics, Mannheim, Germany) compared with the laboratory method. MATERIAL AND METHOD: Paired venous blood INRs were performed in 220 consecutive outpatient tests mainly in anticoagulated (n = 210) and non-anticoagulated (n = 10) individuals. Accuracy was evaluated in 220 tests by parallel assessment of INRs (CoaquChek and laboratory). Accuracy was determined using statistic regression analysis and clinical agreement (expanded and narrow criteria). Agreement in dual INR measurement also was evaluated as a function of increasing INR. RESULTS: The CoaguChek significantly correlated with the laboratory measurement (r = 0.89). The proportion of dual INR measurements that satisfied the clinical relevant expanded, and narrow agreement criteria was 90 per cent and 86 per cent respectively. Eighty-two per cent of all dual measurements were within 0.5 INR units. The accuracy of the portable monitor was greatest for INR values less than 3.0; above this INR level the portable monitor overestimated laboratory INR values. CONCLUSIONS: The CoaguChek is an accurate alternative to laboratory assessment of INR at values < 3.0. The authors suggest the use of the monitor in non anticoagulated patients or anticoagulated patients at values less than 3, as most physicians in Thailand prefer lower INR than in Western countries.

Serum N-terminal pro-brain natriuretic peptide in normal Thai subjects.

Aminoterminal portion of pro-brain natriuretic peptide (NT-proBNP) appears to be useful in the screening, diagnosis and prognosis of left ventricular dysfunction and congestive heart failure. The purpose of this study was to determine the values of serum NT-proBNP in normal Thai subjects compared with subjects from other countries. The design is a cross sectional study. The authors enrolled 243 consecutive healthy subjects (134 males and 109 females) from the checkup department of Bangkok Hospital for NT-proBNP measurement. The serum fraction was measured for NT-proBNP concentration by using Elecsys 2010 (Roche Diagnostics, Switzerland). The concentrations of NT-proBNP in normal Thai subjects were 33.30 +/- 35.43 pg/ml. The NT-proBNP levels increased with age (age < or = 50 years = 27.56 + 28.77 pg/ml and age > 50 years = 47.20 +/- 45.18 pg/ml, p < 0.001). Females usually have higher NT-proBNP than males (females = 40.42 +/- 31.59 pg/ml, males = 27.51 +/- 37.40 pg/ml, p = 0.0045). This study established the NT-proBNP concentrations in normal Thai subjects, which were not different from other studies. The authors suggested the normal cut-off values for subjects aged < or = 50 years should be 100 pg/ml and the normal cut-off values for subjects aged > 50 years should be 200 pg/ml. The NT-proBNP assay could be used as a rule out marker for heart failure in patients and may trigger further cardiac investigation.

Radiofrequency catheter ablation of ventricular tachycardia from right ventricular outflow tract.

From January 1996 to May 2002, 61 patients with ventricular tachycardia from right ventricular outflow tract were referred to Siriraj hospital. All patients underwent clinical examination, Doppler echocardiography and electrophysiologic study. Mapping of ventricular tachycardia was performed by activation mapping and pacemapping. There were 44 females and 17 males with an average age of 41.7 +/- 9.9 years. Presenting symptoms were palpitation (95.1%), presyncope (39.3%), and syncope (26.2%). Six patients were found to have underlying cardiac disease. Radiofrequency catheter ablation was successful in 56 patients (91.8%). There were no major complications. Seven patients (12.5%) had recurrent ventricular tachycardia. Five of them were successfully reablated. The authors concluded that radiofrequency ablation is an effective treatment in patients with ventricular tachycardia from right ventricular outflow tract.

A randomized clinical trial of the efficacy of radiofrequency catheter ablation and amiodarone in the treatment of symptomatic atrial fibrillation.

The limited efficacy and proarrhythmic risks of antiarrhythmia agents have resulted in alternative therapeutic approaches. Radiofrequency ablation has been reported to be an effective treatment of patients with atrial fibrillation. However, there is no randomized clinical trial comparing drug and radiofrequency ablation. The authors randomized 30 patients with chronic atrial fibrillation refractory to medication into amiodarone and radiofrequency ablation. The primary objective of this study was to compare the efficacy of amiodarone and radiofrequency ablation in the maintenance of sinus rhythm at 1 year after randomization. Pulmonary vein isolation and linear ablation of right atrium was the technique used for radiofrequency ablation. There were no significant differences in baseline patient characteristics between the 2 groups. The results of this study showed that the probability of free from atrial fibrillation was better in the radiofrequency ablation group compared to amiodarone (78.6% in the ablation group and 40% in the amiodarone group, p = 0.018). Radiofrequency ablation results in a significant reduction in symptoms relating to atrial fibrillation and a significant improvement in quality of life, whereas amiodarone had no significant effect on symptoms and quality of life. There was an ischemic stroke as a major complication related to radiofrequency ablation. Amiodarone was associated with adverse effects in 46.7 per cent of patients and needed discontinuation in 1 patient. In conclusion, radiofrequency ablation is an effective alternative treatment in patients with atrial fibrillation refractory to medication.

Accuracy of magnetic resonance imaging in the diagnosis of coronary artery disease.

BACKGROUND: Coronary magnetic resonance angiography is a noninvasive method to visualize coronary arteries. The objective of this study was to determine the accuracy of coronary magnetic resonance imaging in the detection of coronary artery stenosis. METHOD: The authors studied 61 patients who were scheduled for their first diagnostic X-ray coronary angiography. Magnetic resonance imaging of the coronary arteries under free-breathing was performed prior to the catheterization schedule. The results were compared. RESULTS: Forty-one out of 61 patients (67.2%) had significant coronary stenosis of at least one major coronary artery. Sixteen (26.2%) had triple vessel disease. A total of 391 of 427 segments had interpretable image quality (91.6%). The diagnostic accuracy of the left main artery, left anterior descending artery, left circumflex artery, and right coronary artery was 96.7 per cent, 90 per cent, 80 per cent and 85.2 per cent respectively. The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of the detection of any significant coronary disease were 97.6 per cent, 75 per cent, 91.2 per cent, 90.9 per cent and 92.3 per cent respectively. CONCLUSIONS: Coronary magnetic resonance imaging is an accurate non-invasive imaging technique in the detection of coronary artery stenosis.

Myocardial diseases in Thai children.

Myocardial diseases are among the important causes of mortality and morbidity in children. This drew the authors attention to the study of myocardial diseases in children to find out the outcome, factors affecting the outcome, and management strategies. The authors retrospectively studied children who had been diagnosed with primary myocardial diseases at six university hospitals in Thailand from January 1996 to December 2000. The total number of cases was 209 which accounted for 1.2 per cent of cardiovascular diseases in children. The patients' ages ranged from 0.1-15 years. These myocardial diseases included dilated cardiomyopathy (DCM) 45 per cent, acute myocarditis 27.3 per cent, hypertrophic cardiomyopathy (HCM) 18.2 per cent, hypertrophic obstructive cardiomyopathy (HOCM) 8.1 per cent and restrictive cardiomyopathy (RCM) 1.4 per cent. Fifty-six per cent of the patients were female. Congestive heart failure was the most common presenting symptom (75%). Median ejection fraction (EF) of acute myocarditis was 42 per cent (15-79%) which was significantly higher than DCM (33.5%, 10-57%). Serum cardiac troponin T (cTnT) was also significantly higher in acute myocarditis than in DCM (0.08 ng/ml, 0.01-0.16 vs 0.01 ng/ml, 0.01-0.10). Within the follow-up period of 1 year (0.1-5.5 years), the mortality rates were 18.8 per cent, 17.0 per cent, 5.4 per cent and 33.3 per cent in DCM, acute myocarditis, HCM and RCM respectively. Factors associated with the mortality rate in acute myocarditis were admission to ICU and low left ventricular EF at presentation while IVIG administration and cTnT level did not. Conclusion: Primary myocardial diseases are uncommon. Most of the patients had compromised cardiovascular reserve. Admission to ICU and low EF were factors that affected the mortality in acute myocarditis while intravenous immunoglobulin administration did not. Mortality rate in the subacute follow-up period was high in all groups.

Cardiac magnetic resonance imaging of atrial septal defect for transcatheter closure.

BACKGROUND: The location, size of the defect and age of the patient are the major determining factors for transcatheter closure of an atrial septal defect (ASD). The precise shape and anatomy surrounding the defect cannot always be understood by the traditional transesophageal (TEE) echocardiographic technique. OBJECTIVES: The authors compared the measurement of ASD size and atrial septal rim using cardiac Magnetic Resonance Imaging (MRI) and TEE to the balloon sizing technique and device size. PATIENTS AND METHOD: Patients having an ASD which met established criteria were selected for evaluation with cardiac MRI and TEE for a closure procedure. Comparison of the ASD imaging and sizing between the different methods was made. RESULTS: There were 22 patients who had complete transcatheter closure. The mean age and standard deviation of the patients was 33.2+/-15.1 (8-67) years old. The mean weight of the patients was 51.6+/-13.1 (20-99) kg. The average cardiac MRI measurement of the ASD was 24.9+/-6.4 mm compared to the TEE measurement of 20.8+/-5.5 mm. The transcatheter balloon measurement of the ASD was 25.2+/-6.9 (11-36) mm and the device closure size was 24.8+/-6.6 (11-36) mm. The correlation coefficient of cardiac MRI to device closure size was r = 0.784 (p < 0.001) when compared to TEE measurement to device closure size; r = 0.761 (p = 0.001). CONCLUSION: The authors demonstrated the capability of the cardiac MRI in assessment of the ASD morphology and anatomy for transcatheter closure of the ASD with an Amplatzer Septal Occluder. Cardiac MRI can provide information about the type, location, size of the defect and direct visualization of the atrial septum anatomy. This detailed information enabled us to provide a safer, more effective application of the ASD occluder.

Early detection of cardiac involvement in beta-thalassemia children.

BACKGROUND: Beta-thalassemia major and beta-thalassemia/HbE are the important causes of chronic hemolytic anemia in Thailand. The objectives of the study were to determine variables associated with cardiac involvement in asymptomatic beta-thalassemia patients. PATIENTS AND METHOD: The authors studied beta-thalassemia major and beta-thalassemia/HbE patients who came to the clinic between July 1st 1999 and July 31st 2000. There were 211 asymptomatic patients included in study. Their ages ranged from 2.6 to 18.2 years. Previous clinical history including blood transfusion and iron chelation were recorded. All patients received a thorough physical examination, chest X-ray, electrocardiogram and echocardiogram. Patients who had abnormal systolic or diastolic function detected by echocardiogram were identified as having cardiac involvement. RESULTS: Cardiac involvement was found in 26 patients (12.3%). There was no difference in physical examination between patients who had and did not have cardiac involvement. Abnormal chest X-Ray defined as cardiothoracic (CT) ratio>0.55 and electrocardiogram (ECG) findings of left or right ventricular hypertrophy were associated with cardiac involvement. Other associated findings were older age and lower average pretransfusion hematocrit (23 +/- 6.6%). CONCLUSIONS: In asymptomatic beta-thalassemia children, chest X-ray and ECG should be used for screening patients for the detection of cardiac involvement.

Transcatheter coil occlusion of small patent ductus arteriosus: experience at Siriraj Hospital.

Transcatheter coil occlusion of small-to-moderate-size patent ductus arteriosus (PDA, < 3.5 mm) is well established as a procedure of first choice in many institutions. Its much lower cost compared with surgical ligation or other devices makes it an attractive option, especially in Thailand. PATIENTS AND METHOD: Between September 1995 and June 2000, all patients diagnosed with PDA with audible murmur and echo-Doppler confirmation of diameter less than 3.5 mm were scheduled for transcatheter coil occlusion at the Department of Pediatrics, Faculty of Medicine Siriraj Hospital. The hemodynamic studies were obtained both pre and post occlusion. The immediate and late outcome, including complication were assessed. RESULTS: A total of 77 cases, 78 procedures of transcatheter PDA coil occlusion were performed. Seventy cases (90.9%), comprised of 19 males (27.1%) and 51 females (72.9%) were successfully deployed with coils. The remainder were unsuccessfully deployed and later referred to surgery. The median age of the successful group was 6 years and 6 months and median weight was 16.5 kg. Twenty cases (28.6%) had other associated intra and extracardiac anomalies. All patients were asymptomatic, except one case having bronchopulmonary dysplasia (BPD) from prolonged ventilation. Single-coil occlusions were performed in 74.3 per cent and double-coil occlusions in 25.7 per cent. Conventional 0.038-inch Gianturco coils were deployed in 86.5 per cent. The mean procedure time was 78.1 +/- 35.1 minutes. The mean fluoroscopic time was 20.2 +/- 15.6 minutes. The total complete occlusion rate was 87.7 per cent. Tiny residual flow of PDA was demonstrated by follow-up echocardiogram in 12.3 per cent. Seven per cent of the patients were lost to follow-up. There was no significant difference in PDA size and hemodynamics between the groups of patients with complete occlusion and having residual shunt. Minor complications occurred in 12.9 per cent, including mild left pulmonary artery stenosis (10%), coil embolization to distal pulmonary artery (8.6%), slippage of catheter with coil (2.9%) and decreased dorsalis pedis pulse (1.4%). One late death was found in a BPD patient from pneumonia 2 months after the procedure. CONCLUSION: Transcatheter coil occlusion of PDA is as effective, feasible, safe and less costly than surgical ligation. With improvement in technique and device selection and appropriate case selection, there should be an increase rate of complete occlusion and a decrease in complications.