High on-clopidogrel treatment platelet reactivity in Thai patients with chronic stable angina scheduled for percutaneous coronary intervention.

OBJECTIVE: To determine the prevalence, clinical profile, and risk factors of high on-clopidogrel treatment platelet reactivity in Thai patients with chronic stable angina scheduled for percutaneous coronary intervention. MATERIAL AND METHOD: The patients were prospectively recruited from the consecutive patients undergoing coronary angiography and planned for elective percutaneous coronary intervention (PCI). Ten ml of blood samples were cautiously drawn from the antecubital vein of the patients to determine the hemoglobin and platelet count. Platelet aggregation test was performed by light transmittance aggregometry using platelet-rich plasma. Platelets were stimulated with 5 microM adenosine diphosphate (ADP). Platelet aggregation was expressed as the maximal percent change in light transmittance from baseline. High on-clopidogrel treatment platelet reactivity was defined as post treatment maximal platelet aggregation > 46% with 5 micromol/l ADP used as agonist. RESULTS: The present study consecutively enrolled two hundred four patients diagnosed with chronic stable angina planned for PCI. Seventy-nine patients demonstrated the high on-clopidogrel treatment platelet reactivity (38.7%). Among these patients, 48% were men with a mean age of 66 years. Diabetes mellitus and chronic kidney disease were detected in 34.2%. Original clopidogrel (Plavix) was prescribed in 72% of the patients and 28% received generic clopidogrel (Apolets). The prevalence of high on-clopidogrel treatment platelet reactivity increased in the older patients, patients with CKD and patients receiving angiotensin receptor blockers (ARB). However from multivariate analysis, none of the risk factors, including age, BMl, diabetes mellitus, smoking, CKD, ARB use, and type of clopidogrel (Plavix versus Apolets) had a statistically significant association with the high on-clopidogrel treatment platelet reactivity. CONCLUSION: The prevalence of high on-clopidogrel treatment platelet reactivity in the present study was 38.7%. No significant association was demonstrated between age, BMI, diabetes mellitus, smoking, CKD, ARB use, type of clopidogrel, and high on-clopidogrel treatment platelet reactivity.

Prognostic value of normal dobutamine stress echocardiography in renal transplant candidates.

BACKGROUND: Renal transplant candidates are at high-risk for cardiovascular events. No definite screening tool has been recommended for the pre-operative evaluation. OBJECTIVE: The authors studied the prognostic value of normal dobutamine stress echocardiography in this population. MATERIAL AND METHOD: Dobutamine stress echocardiography was performed for the pre-operative assessment in 107 renal transplant candidates (age 53.2 +/- 6.2 years, 66.4% male). The mean follow-up time was 2.8 +/- 1.7 years. The primary endpoint was total mortality. RESULTS: During follow-up, 16 (15.0%) died and 26 (24.3%) patients underwent kidney transplantation. The overall survival probabilities at 1, 3 and 5 years were 87, 83 and 79%, respectively. Among those who underwent renal transplantation, the survival probabilities at 1, 3 and 5 years were 100, 100 and 89%, respectively CONCLUSION: In renal transplant candidates, normal dobutamine stress echocardiography portends a good long-term prognosis.

Dobutamine stress echocardiography for the evaluation of coronary artery disease in Thai population: Siriraj experience.

OBJECTIVE: No previous report of dobutamine stress echocardiography in the Thai population has been available. The present study seeks to document the protocol, indications, results and safety of dobutamine stress echocardiography performed at Siriraj Hospital. MATERIAL AND METHOD: The authors studied 421 [mean age 67.7 +/- 11.0 years, 179 (43%) men] consecutive Thai patients undergoing dobutamine stress echocardiography at Siriraj Hospital. The protocol, indications and echocardiographic analysis were described. Clinical characteristics, hemodymanics, results and adverse effects were recorded at the time of dobutamine stress echocardiography. RESULTS: Dobutamine stress echocardiography was performed for preoperative assessment before non-cardiac surgery in 212 patients (50%), for the diagnosis of suspected Coronary Artery Disease (CAD) in 179 patients (43%), for risk stratification of CAD in 24 patients (6%), and for other reasons in six patients (1%). The results were normal and positive for inducible ischemia in 276 (66%) and 80 (19%) patients, respectively. Limiting side effects were observed in 3%. No death, myocardial infarction or life-threatening arrhythmias occurred. Transient stress-associated tachyarrhythmias, such as atrialfibrillation, nonsustained ventricular tachycardia or supraventricular tachycardia, occurred in 3.5% of patients. CONCLUSION: Dobutamine stress echocardiography was considered a safe and tolerable technique for the evaluation of CAD in Thai population.

An abnormal systemic and regional hypercoagulable state in patients with mitral stenosis.

Mitral stenosis still remains a major problem in Southeast Asia including Thailand. It contributes to the morbidity and mortality related to thromboembolism which was associated with the left atrial thrombus. However, the pathogenesis of left atrial thrombus in these patients is not completely understood. Therefore, the objective of this study was to investigate the coagulation and platelet activity including the function of the endocardium in the left atrium and peripheral circulation in patients with mitral stenosis who were free of left atrial thrombus and to compare those hematologic markers activity in the peripheral venous blood between the patients with mitral stenosis and the control. Thirty-six patients with moderate to severe mitral stenosis were included in the study. Most of the patients were in functional class II and 50 per cent had atrial fibrillation. Blood was obtained from the femoral vein, femoral artery, pulmonary artery and left atrium of these patients before heparin was administered to determine the value of various hematologic markers. In the control group, blood for determining the hematologic markers was collected only from the antecubital vein. The results of this study demonstrated that the levels of prothrombin activation fragment 1+2 (F1+2), thrombin-antithrombin III complex (TAT) and Beta-thromboglobulin (beta-TG) in the left atrium of the patients with mitral stenosis were significantly higher than those in the femoral vein and femoral artery, whereas the level of thrombomodulin was significantly lower in the left atrium compared with the femoral artery and vein. When comparing with the control group, the levels of TAT, plasminogen activator inhibitors-1 (PAI-1) from the peripheral vein were significantly higher and the level of thrombomodulin was also significantly lower in the patients with mitral stenosis. In conclusion, the present study demonstrated an abnormal hypercoagulable state of the left atrium and systemic circulation related to the abnormalities of coagulation, platelets and the endocardium which may cause the formation of left atrial thrombus in patients with mitral stenosis.