Takayuki Kawata

Influencing factors on cardiac structure and function beyond glycemic control in patients with type 2 diabetes mellitus

BackgroundWe hypothesized that clinical factors other than glycemic control may influence abnormal cardiac function in patients with type 2 diabetes mellitus (T2DM). We aimed to investigate the independent factors for abnormal cardiac function among clinical factors in T2DM.MethodsWe studied 148 asymptomatic patients with T2DM without overt heart disease. Echocardiographic findings were compared between diabetic patients and 68 age-matched healthy subjects. Early (E) and late (A) diastolic mitral flow velocity and early diastolic mitral annular velocity (e’) were measured for assessing left ventricular (LV) diastolic function. We evaluated insulin resistance, non-esterified fatty acid, high-sensitive CRP, estimated glomerular filtration rate, waist/hip ratio, abdominal visceral adipose tissue (VAT), subcutaneous adipose tissue (SAT) and other clinical characteristics in addition to glycemic control. VAT and SAT were quantified by computed tomography.ResultsIn T2DM, E/A and e’ were significantly lower, and E/e’, left atrial volume and LV mass were significantly greater than in control subjects. In multivariate liner regression analysis, VAT was an independent determinant of left atrial volume (β =0.203, p=0.011), E/A (β =−0.208, p=0.002), e’ (β =−0.354, p<0.001) and E/e’ (β=0.220, p=0.003). Age was also an independent determinant, whereas fasting plasma glucose and hemoglobin A1c levels were not. In addition to systolic blood pressure, waist-hip ratio (β=0.173, p=0.024) and VAT/SAT ratio (β=0.162, p=0.049) were independent determinants of LV mass.ConclusionExcessive visceral fat accompanied by adipocyte dysfunction may play a greater role than glycemic control in the development of diastolic dysfunction and LV hypertrophy in T2DM.

Wavering calcified amorphous tumour of the heart in a haemodialysis patient

Calcified amorphous tumour is a rare, non-neoplastic, endocardially based, intracavitary cardiac mass. This report describes a 59-year old man in whom a mobile mass was found incidentally in the heart by routine echocardiography after he had been on haemodialysis for 3 years. Transoesophageal echocardiography revealed a high-echoic swinging tumour that originated from the annulus of the anterior commissure of the mitral valve. Surgical resection was performed to prevent embolization, and his clinical course was excellent.

The impact of sleep deprivation on the coronary circulation

Epidemiologic studies have reported that sleep deprivation is associated with cardiovascular events. However, it remains unknown how sleep deprivation affects the coronary circulation. We assessed the impact of sleep deprivation on the coronary circulation using coronary flow velocity reserve (CFVR) measurements with transthoracic Doppler echocardiography. We studied 26 healthy male volunteers. Each subjects CFVR was measured in the morning after sleep deprivation (less than 4 h) or normal sleep (more than 7 h) on different days. Sleep durations were 3.7 ± 0.9 h (sleep deprivation) and 7.1 ± 0.2 h (normal sleep). CFVR after sleep deprivation was significantly lower than that after normal sleep (3.3 ± 0.6 versus 4.2 ± 0.9, p<0.001). Short sleep duration attenuated CFVR compared with normal sleep duration. This finding suggests that sleep deprivation might serve as a trigger for cardiovascular events.

Evaluation of Right Ventricle by Speckle Tracking and Conventional Echocardiography in Rats With Right Ventricular Heart Failure

Speckle tracking echocardiography (STE) has been reported to be a promising technique for evaluating right ventricular (RV) function in the clinical setting. On the other hand, the usefulness of STE for RV evaluation in small animal models has not been clarified, although the rat model is among the most commonly used animal models to develop novel effective treatments against pulmonary hypertension and RV heart failure (HF).We validated the use of STE and conventional echocardiographic variables for evaluating RV functions in a rat model by comparing the echocardiographic values of RVHF rats (n = 12) induced by monocrotaline injection with those of control rats (n = 12).Most conventional echocardiographic variables demonstrated that RVHF rats have significant RV dysfunction. The area under the curve (AUC) values to distinguish RV dysfunction in RVHF rats from normal RV function in control rats using fractional area change (FAC), tricuspid annular plane systolic excursion (TAPSE), RV myocardial performance index (MPI), peak tissue Doppler tricuspid annular velocities at systole (Sa), and at early diastole (Ea) were 0.71, 0.98, 0.79, 0.92, and 0.91, respectively. However, using STE analysis for RV evaluation, limited reproducibility was observed (variability 19-37 %, ICC 0.74-0.88) and the only circumferential strain showed significantly lower absolute values (P = 0.039, AUC = 0.76).To evaluate RV function in rat models, circumferential strain may be useful, however, the reproducibility and diagnostic utility were limited. Conventional echocardiographic variables such as TAPSE, tissue Doppler Sa, and Ea have superior diagnostic utility.

Relationship of Left Ventricular Diastolic Function to Obesity and Overweight in a Japanese Population With Preserved Left Ventricular Ejection Fraction

BACKGROUND Obesity has been found to be associated with future development of diastolic heart failure. Other evidence has indicated that the effect of obesity on left ventricular (LV) mass varies among ethnicities. However, there are few data on the relationship between body mass index (BMI) and LV diastolic dysfunction in the Japanese population. METHODSANDRESULTS We performed echocardiography in 788 subjects without valvular disease or LV systolic dysfunction. They were divided into 3 groups by BMI: normal weight, overweight, and obese. We used multivariable linear regression analysis to assess the clinical variables associated with diastolic parameters, including BMI. We also assessed the risk of diastolic dysfunction associated with BMI using multivariable logistic models. Overweight and obese subjects had significantly worse LV diastolic function and greater LV mass than normal weight subjects. In the multivariable analysis, BMI was independently associated with diastolic parameters. Furthermore, after adjusting for clinical factors, the increased risks of diastolic dysfunction in overweight subjects (adjusted odds ratio: 2.02, 95% confidence interval 1.21-3.36) and obese subjects (4.85, 3.36-16.27) were greater than those previously observed in Western populations. CONCLUSIONS The Japanese population might be more susceptible than Western subjects to the effect of BMI on LV diastolic function. Differences between ethnicities should be taken into consideration in strategies for the prevention of diastolic heart failure. (Circ J 2016; 80: 1951-1956).

Serum asymmetric dimethylarginine as a marker of coronary microcirculation in patients with non-insulin dependent diabetes mellitus: correlation with coronary flow reserve

Abnormalities of coronary microcirculation without large vessel atherosclerosis have been known in patients with non-insulin dependent diabetes mellitus (NIDDM). Coronary flow reserve (CFR) has been considered an important physiological parameter in the coronary circulation reflecting the function of large epicardial arteries and the microcirculation, including endothelial function. Reduced CFR and impaired endothelium mediated, nitric oxide dependent coronary vasodilatation1,2 have been observed in NIDDM without overt coronary artery disease. Asymmetric dimethylarginine (ADMA) is a major endogenous nitric oxide synthase inhibitor and has been considered a novel risk factor of cardiovascular disease.3 Serum or plasma concentration of ADMA is increased in patients with NIDDM3 and may attenuate vascular function. However, to our knowledge, the relation between ADMA and CFR has not been examined in patients with NIDDM. Our goal was to examine the relation between serum ADMA concentration and CFR in patients with NIDDM by means of non-invasive transthoracic Doppler echocardiography. We studied 47 patients with NIDDM without a history of cardiovascular disease. We limited our study population to non-smokers and patients treated with diet or oral hypoglycaemic agents alone. All patients underwent two dimensional echocardiography and a treadmill exercise test …

Factors influencing left atrial volume in a population with preserved ejection fraction: Left ventricular diastolic dysfunction or clinical factors?

BACKGROUND Increased left atrial volume (LAV) predicts a higher incidence of cardiovascular events and is widely recognized as a major surrogate marker of left ventricular (LV) diastolic dysfunction (DD). Although the pathophysiology of LA enlargement is probably multifactorial, few studies have examined comprehensively the clinical factors that lead to LA enlargement in the absence of valvular disease or LV systolic dysfunction. Therefore, we investigated associations between LAV and several clinical and echocardiographic parameters including DD. METHODS We enrolled 557 subjects without significant valve disease or LV systolic dysfunction from the health check-up clinic retrospectively. We performed univariable and multivariable linear regression using lnLAV index as the dependent variable and the following independent variables: gender, age, smoking status, drinking habit, hypertension, diabetes, body mass index (BMI), LV ejection fraction, DD, LV mass index, hemoglobin, serum creatinine, serum total cholesterol, serum uric acid, serum sodium, and serum iron. RESULTS In multivariable analysis, LAV index was independently associated with BMI, lower hemoglobin, and moderate and severe DD compared with normal diastolic function (p<0.001), but not with mild DD (p=0.70). CONCLUSIONS LA enlargement was independently associated with moderate and severe DD, but not with mild DD. Furthermore, obesity and lower hemoglobin were associated with LAV independently of DD.

Prognostic impact of venous thromboembolism in patients with Duchenne muscular dystrophy: Prospective multicenter 5-year cohort study

Please cite this article as: Kimura Koichi, Morita Hiroyuki, Daimon Masao, Kawata Takayuki, Nakao Tomoko, Lee Seitetsu L., Hirokawa Megumi, Ebihara Aya, Nakajima Takashi, Ozawa Tetsuo, Yonemochi Yosuke, Aida Izumi, Motoyoshi Yasufumi, Mikata Takashi, Uchida Idai, Komori Tetsuo, Kitao Ruriko, Nagata Tetsuya, Takeda Shin’ichi, Komaki Hirofumi, Segawa Kazuhiko, Takenaka Katsu, Komuro Issei, Prognostic Impact of Venous Thromboembolism in Patients with Duchenne Muscular Dystrophy: Prospective Multicenter 5-Year Cohort Study, International Journal of Cardiology (2015), doi: 10.1016/j.ijcard.2015.04.244

Significance of Coronary Artery Disease and Left Ventricular Afterload in Unoperated Asymptomatic Aortic Stenosis.

BACKGROUND Because the covariates of cardiovascular events in unoperated patients with asymptomatic aortic stenosis (AS) have not been adequately evaluated, we aimed to identify them. METHODSANDRESULTS A total of 230 patients with asymptomatic severe AS were retrospectively enrolled. The patients were divided into 2 groups based on aortic valve replacement (AVR) after enrollment: a non-AVR group (n=112), and an AVR group (n=118). The primary clinical endpoint was cardiovascular events, which were defined as cardiovascular death or hospitalization. Coronary artery disease [hazard ratio (HR): 3.62, 95% confidence interval (CI): 1.585-8.245, P<0.01] and high valvulo-arterial impedance (HR: 3.08, 95% CI: 1.261-7.532, P<0.05) were identified as independent covariates of cardiovascular events in the non-AVR group. The relative risk of cardiovascular events rose with an increase in the number of risk factors (P<0.0001). CONCLUSIONS In unoperated patients with asymptomatic AS, the presence of coronary artery disease and increased global left ventricular afterload may be associated with a poor prognosis.

Cibenzoline improves coronary flow velocity reserve in patients with hypertrophic obstructive cardiomyopathy

The effect of cibenzoline, a class-Ia antiarrhythmic drug, on coronary flow velocity reserve (CFVR) was examined in patients with hypertrophic cardiomyopathy using transthoracic Doppler echocardiography. Coronary flow velocity reserve was assessed in 11 patients with hypertrophic obstructive cardiomyopathy (HOCM) and 12 patients with hypertrophic nonobstructive cardiomyopathy (HNCM), before and after the intravenous administration of cibenzoline (1 mg/kg). Coronary hyperemia was induced by an intravenous infusion of adenosine triphosphate and CFVR was calculated as the ratio of hyperemic to basal mean coronary diastolic flow velocity. At baseline, CFVR was significantly correlated with left ventricular outflow tract pressure gradient (LVPG) in patients with HOCM (r = 0.67, P < 0.03). In patients with HOCM, administration of cibenzoline significantly improved impaired CFVR (2.0 ± 0.8 to 3.0 ± 1.0, P < 0.001), and reduced LVPG (55 ± 30 to 23 ± 18 mmHg, P < 0.001), while CFVR remained unchanged in patients with HNCM (2.6 ± 0.9 to 2.9 ± 0.8, P not significant). Cibenzoline not only reduces LVPG but also improves CFVR in patients with HOCM. In addition left ventricular outflow obstruction plays an important role in impaired coronary circulation in patients with HOCM.