Association of platelet aggregation with lipid levels in the Japanese population: the Suita study.

AIM: Platelets play a pivotal role in atherothrombotic diseases. Platelet aggregability induced by agonists has great interindividual variability; however, the factors influencing platelet aggregability variation have not been characterized in Asia. METHODS: To examine the confounding factors influencing platelet counts and responsiveness to agonists, we measured the platelet counts and platelet aggregability induced by 1.7 µM adenosine diphosphate (ADP) or 1.7 µg/mL collagen using a light transmittance aggregometer in the Japanese general population without medication or cardiovascular disease (387 men and 550 women) in the Suita Study. RESULTS: Platelet counts were negatively correlated with age in both men and women (Spearman's rank correlation coefficient: r(s)=-0.230 and -0.227; p< 0.01, respectively). In women, platelet counts were correlated negatively with the high-density lipoprotein (HDL) cholesterol level and positively with the low-density lipoprotein (LDL) cholesterol/HDL cholesterol (L/H) ratio (r(s)=-0.135 and 0.119; p< 0.01, respectively). In women, platelet aggregabilities by ADP and collagen were correlated with age (r(s)=0.118 and 0.143; p< 0.01, respectively), and collagen-induced platelet aggregability was correlated with the LDL cholesterol level, the L/H ratio, and the non-HDL cholesterol level (r(s)=0.167, 0.172, and 0.185; p< 0.01, respectively). Even after adjustment for age, systolic blood pressure, body mass index, and current smoking and drinking, the association of platelet counts with the L/H ratio in women and associations of collagen-induced platelet aggregability with the L/H ratio and the non-HDL cholesterol level remained. CONCLUSION: Examination of platelet counts and platelet aggregability induced by ADP and collagen revealed gender, age and lipid levels as factors influencing inter-individual variability.

Usefulness of antithrombin deficiency phenotypes for risk assessment of venous thromboembolism: type I deficiency as a strong risk factor for venous thromboembolism.

Inherited antithrombin deficiency, an established risk factor for venous thromboembolism (VTE), can be classified into type I (quantitative deficiency) or type II (qualitative deficiency). In the present study, we assessed the VTE risk associated with the phenotypes of antithrombin deficiency in patients admitted to our hospital. We found that patients with type I deficiency (n = 21) had more VTE events and earlier onset of VTE than those with type II deficiency (n = 10). The VTE-free survival analysis showed that the risk for VTE in patients with type I deficiency was sevenfold greater than that in patients with type II deficiency (hazard ratio: 7.3; 95% confidence interval: 1.9-12.2; P = 0.0009). The prevalence of type I deficiency in the VTE group (5.6%, 6/108) was higher than that in the general population (0.04%, 2/4,517) (odds ratio: 132.8; 95% confidence interval: 26.5-666.1; P < 0.0001). However, the prevalence of type II deficiency was not different between the VTE group and the general population. Our study indicated that the risk for VTE in patients with type I deficiency was much higher than that in patients with type II deficiency. Thus, simple phenotypic classification of antithrombin deficiency is useful for assessment of VTE risk in Japanese.

Transmitral E/A ratio decreases in association with abdominal fat accumulation in patients with impaired glucose tolerance or mild diabetes without left ventricular hypertrophy.

An abnormal left ventricular (LV) diastolic function is an early sign of diabetic cardiomyopathy, which is characterized by an impaired diastolic and/or systolic function of the left ventricle in the absence of ischemic, valvular, or hypertensive heart disease, and serves as a marker of cardiovascular risk. However, it is unclear whether LV diastolic abnormalities can be detected in patients with impaired glucose tolerance (IGT) or mild diabetes without LV hypertrophy (LVH). We examined echocardiographic data from 92 consecutive Japanese patients aged 45-79 years with or without IGT or mild diabetes in the absence of LVH. Impaired glucose tolerance or mild diabetes was defined as the presence of one or more of the following criteria: fasting plasma glucose >110 mg/dl, hemoglobin A1c >5.6%, homeostasis model assessment ratio >1.73, or the taking of oral antihyperglycemic drugs. Left ventricular hypertrophy was defined as an LV mass index (LVMI) >116 g/m(2) in men and >104 g/m(2) in women. Patients with ischemic, valvular, or hypertensive heart disease were excluded. The age, blood pressure, heart rate, and LVMI were similar between patients with (IGT/DM group, n = 43) and without IGT or mild diabetes (non-IGT/DM group, n = 49), whereas the body mass index and waist circumference (WC) were greater in the IGT/DM compared to the non-IGT/DM group (P < 0.05 and P < 0.001, respectively). The transmitral E/A ratio was lower and the deceleration time longer in the IGT/DM than in the non-IGT/DM group (both P < 0.05). Stepwise regression analysis revealed that age and WC were independent determinants of the E/A ratio. In conclusion, diastolic abnormalities without LVH can be detected in Japanese patients with IGT or mild diabetes. The E/A ratio decreases in association with abdominal fat accumulation.