Norihiko Ohashi

Association between epicardial adipose tissue volume and characteristics of non-calcified plaques assessed by coronary computed tomographic angiography

BACKGROUND The aim of this study was to investigate whether high epicardial adipose tissue (EAT) volume is related to the presence of vulnerable coronary plaque components as assessed by computed tomography (CT). METHODS We evaluated 357 patients referred for 64-slice CT, and assessed coronary plaque components and EAT volume. Vulnerable coronary plaque components were defined as the presence of non-calcified plaque (NCP), including low-density plaque (LDP: <39 HU) and positive remodeling (PR: remodeling index>1.05). In accordance with a previous report, patients were assigned to two groups: low (<100 ml) or high (≥100 ml) EAT volume. RESULTS Compared to the low EAT volume group, the high EAT volume group had a higher prevalence of NCP (74% vs. 59%, p=0.003). Additionally, the high EAT volume group had a higher prevalence of LDP with PR than the low EAT volume group (46% vs. 25%, p<0.001). Interestingly, a high EAT volume was an independent predictor of LDP with PR (odds ratio 2.56, 95% confidence interval 1.38-4.85, p=0.003) after adjusting for age, gender, traditional cardiovascular risk factors, body mass index (BMI), abdominal visceral adipose tissue (VAT), and coronary artery calcium (CAC) scores. CONCLUSIONS A high EAT volume was associated with the presence of vulnerable plaque components, independent of obesity measurements (BMI and VAT) and CAC scores.

Association between visceral adipose tissue area and coronary plaque morphology assessed by CT angiography.

OBJECTIVES We sought to investigate the association between visceral adipose tissue (VAT) with the presence, extent, and characteristics of noncalcified coronary plaques (NCPs) using 64-slice computed tomography angiography (CTA). BACKGROUND Although visceral adiposity is associated with cardiovascular events, its association with NCP burden and vulnerability is not well known. METHODS The study population consisted of 427 patients (age 67 ± 11 years; 63% men) with proven or suspected coronary artery disease who underwent 64-slice CTA. We assessed the presence and number of NCPs for each patient. The extent of NCP was tested for the difference between high (≥ 2) and low (≤ 1) counts. We further evaluated the vulnerable characteristics of NCPs with positive remodeling (remodeling index >1.05), low CT density (≤ 38 HU), and the presence of adjacent spotty calcium. Plain abdominal scans were also performed to measure the VAT and subcutaneous adipose tissue area. RESULTS A total of 260 (61%) patients had identifiable NCPs. Multivariate analyses revealed that increased VAT area (per 1 standard deviation, 58 cm(2)) was significantly associated with both the presence (odds ratio [OR]: 1.68; 95% confidence interval [CI]: 1.28 to 2.22) and extent (OR: 1.31; 95% CI: 1.03 to 1.68) of NCP. Other body composition measures, including subcutaneous adipose tissue area, body mass index, and waist circumference were not significantly associated with either presence or extent of NCP. Increased VAT area was also independently associated with the presence of NCP with positive remodeling (OR: 1.71; 95% CI: 1.18 to 2.53), low CT density (OR: 1.69; 95% CI: 1.17 to 2.47), and adjacent spotty calcium (OR: 1.52; 95% CI: 1.03 to 2.27). CONCLUSIONS Increased VAT area was significantly associated with NCP burden and vulnerable characteristics identified by CTA. Our findings may explain the excessive cardiovascular risk in patients with visceral adiposity, and support the potential role of CTA to improve risk stratification in such patients.

Visceral fat accumulation as a predictor of coronary artery calcium as assessed by multislice computed tomography in Japanese patients

The impact of visceral adiposity on subclinical coronary atherosclerosis is unclear in Japanese patients. We investigated the sex-specific relationship between the amount of visceral fat and coronary artery calcium (CAC) using multislice computed tomography (MSCT). This is a cross-sectional study of 321 consecutive Japanese patients (213 men and 108 women) who underwent MSCT scanning for the examination of coronary heart disease. CAC score, visceral fat area (VFA), subcutaneous fat area (SFA), and waist circumference (WC) were determined by MSCT for all patients. The prevalence of detectable CAC was 73% and 57% in men and women, respectively. Using a multivariable logistic and ordinal regression analyses adjusting for traditional cardiovascular risk factors and adiposity measurements, VFA represented an independent predictor of the presence and extent of CAC (odds ratio (95% confidence interval) per one-unit-standard deviation increase in VFA: 2.48 (1.23-6.05) in logistic regression analysis; 2.05 (1.18-3.98) in ordinal regression analysis). Similar relationships were observed across the gender. We further assessed the sex-specific cut-off levels of VFA and WC to predict the presence of CAC. The results of receiver operator characteristic analysis indicated that the VFA cut-off level in men was 116cm(2); and in women, it was 82cm(2), corresponding to WC values of 87.7cm in men and 82.6cm in women. In conclusion, we found that visceral adiposity measured by MSCT is significantly associated with the presence and extent of CAC as a marker of subclinical atherosclerosis in Japanese patients.

Noncalcified atherosclerotic lesions with vulnerable characteristics detected by coronary CT angiography and future coronary events

BACKGROUND The ability of coronary CT angiography (CTA) findings such as plaque characteristics to predict future coronary events remains controversial. OBJECTIVE We investigated whether noncalcified atherosclerotic lesions (NCALs) detected by coronary CTA were predictive of future coronary events. METHODS A total of 511 patients who underwent coronary CTA were followed for cardiovascular events over a period of 3.3 ± 1.2 years. The primary end point was defined as hard events, including cardiac death, nonfatal myocardial infarction, or unstable angina that required urgent hospitalization. Early elective coronary revascularizations (n = 58) were excluded. The relationship between features of NCALs and outcomes is described. RESULTS A total of 15 hard events (2 cardiac deaths, 7 myocardial infarctions, 6 cases of unstable angina that required urgent hospitalization) were documented in the remaining 453 patients with modest risks during a follow-up period of 3.3 ± 1.2 years. For these hard events, a univariate Cox proportional hazard model showed that the hazard ratio for the presence of >50% stenosis was 7.27 (95% CI, 2.62-21.7; P = .0002). Although the presence of NCAL by itself was not statistically significant, NCALs with low attenuation and positive remodeling (low-attenuation plaque [LAP] and positive remodeling [PR]; plaque CT number ≤ 34 HU and remodeling index ≥ 1.20) showed an adjusted hazard ratio of 11.2 (95% CI, 3.71-36.7; P < .0001). With C-statistics analysis, when both LAP and PR and >50% stenosis were added, the C-statistic was significantly improved compared with the basal model adjusted for age, sex, and log2 (Agatston score +1) (0.900 vs 0.704; P = .0018). CONCLUSIONS Identification of NCALs with LAP and PR characteristics by coronary CTA provides additional prognostic information to coronary stenosis for the prediction of future coronary events.

Combined presence of aortic valve calcification and mitral annular calcification as a marker of the extent and vulnerable characteristics of coronary artery plaque assessed by 64-multidetector computed tomography

OBJECTIVE We examined the association of aortic valve calcification (AVC) and mitral annular calcification (MAC) to coronary atherosclerosis using 64-multidetector computed tomography (MDCT). BACKGROUND Valvular calcification is considered a manifestation of atherosclerosis. The impact of multiple heart valve calcium deposits on the distribution and characteristics of coronary plaque is unknown. METHODS We evaluated 322 patients referred for 64-MDCT, and assessed valvular calcification and the extent of calcified (CAP), mixed (MCAP), and noncalcified coronary atherosclerotic plaque (NCAP) in accordance with the 17-coronary segments model. We assessed the vulnerable characteristics of coronary plaque with positive remodeling, low-density plaque (CT density ≤38 Hounsfield units), and the presence of adjacent spotty calcification. RESULTS In 49 patients with both AVC and MAC, the segment numbers of CAP and MCAP were larger than in those with a lack of valvular calcification and an isolated AVC (p<0.001 for both). Multivariate analyses revealed that a combined presence of AVC and MAC was independently associated with the presence (odds ratio [OR] 9.36, 95% confidence interval [95%CI] 1.55-56.53, p=0.015) and extent (β-estimate 1.86, p<0.001) of overall coronary plaque. When stratified by plaque composition, it was associated with the extent of CAP (β-estimate 1.77, p<0.001) and MCAP (β-estimate 1.04, p<0.001), but not with NCAP. Moreover, it was also related to the presence of coronary plaque with all three vulnerable characteristics (OR 4.87, 95%CI 1.85-12.83, p=0.001). CONCLUSION The combined presence of AVC and MAC is highly associated with the presence, extent, and vulnerable characteristics of coronary plaque identified by 64-MDCT.

Prognostic value of coronary artery calcium and epicardial adipose tissue assessed by non-contrast cardiac computed tomography

OBJECTIVE Epicardial adipose tissue (EAT) accumulation is believed to be associated with development of coronary atherosclerosis. We investigated whether EAT volume as assessed by computed tomography (CT) has value in prediction of future cardiac events. METHODS We studied 722 patients without proven coronary artery disease (CAD) who underwent non-contrast cardiac CT. EAT volume and coronary artery calcium (CAC) score were measured simultaneously. Patients were followed as to the occurrence of coronary events (cardiac death, nonfatal myocardial infarction, unstable angina requiring hospitalization, and late coronary revascularization≥3 months after CT examination). RESULTS During a 3.7±1.7 years follow-up period, 37 coronary events were documented. Annual event rates increased across CAC score categories (0.3%, 1.0%, 2.4%, and 4.3%, in 0, 1-99, 100-399, and ≥400, respectively, p<0.001); these were significantly higher in the higher EAT volume group (>median; 107.2 mL, 0.7% vs., 2.1%, adjusted hazard ratio; 2.65, p=0.0090). Cox-proportional hazard analysis demonstrated that a combination of CAC score≥100 and high EAT volume had a significantly higher event rate than CAC score<100 and low EAT volume group (adjusted hazard ratio 11.6, p<0.0001). Using Cox regression models, incremental prognostic values were identified by adding high EAT volume to clinical risks plus CAC score≥100 (global χ2, 6.7; p=0.059). CONCLUSION We suggest that high EAT volume may be an independent predictor of future coronary events and increases predictive values of CAC score in patients without proven CAD.

Effects of statin therapy on non-calcified coronary plaque assessed by 64-slice computed tomography

UNLABELLED Computed tomography angiography (CTA) enables characterization of non-calcified coronary atherosclerotic lesions (NCALs) and assessment of plaque vulnerability. We investigated whether the characteristics of NCALs detected by 64-slice CTA were influenced by preceding statin therapy and serum lipid profiles. METHODS Among 493 consecutive patients who underwent coronary CTA, we enrolled 114 patients with NCALs. We divided the patients into three groups according to preceding statin therapy: intensive statins (IS, n=24), moderate statins (MS, n = 26), and no statin (NS, n = 64). The vulnerability of each NCAL was evaluated by density (low-density plaque defined as CT density ≤ 38 HU), positive remodeling (remodeling index > 1.05), and the presence of adjacent spotty calcification. RESULTS Percentages of patients in the IS, MS, and NS groups with low-density NCALs were 46%, 58%, and 80%, respectively (p = 0.009) and positive remodeling NCALs were 54%, 58%, and 75%, respectively (p = 0.10). We also found an inverse correlation between serum LDL-C level and the minimum plaque CT density. According to the regression equation, a CT density of 38 HU corresponded with LDL-C of 100 mg/dl. The number of low-density plaques was positively correlated with low-density to high-density lipoprotein cholesterol ratio (LDL-C/HDL-C). An LDL-C/HDL-C > 2.5 independently predicted multiple low-density plaques (OR 2.39 [95%CI: 1.28-4.86], p < 0.001). CONCLUSIONS Our CTA findings demonstrate that low-density NCALs occur less frequently in patients with intensive statin pre-treatment. A high LDL-C/HDL-C ratio is also associated with larger numbers of low-density NCALs.

The impact of visceral adipose tissue and high-molecular weight adiponectin on cardio-ankle vascular index in asymptomatic Japanese subjects.

Few studies addressed the relation of visceral adiposity and high-molecular weight (HMW) adiponectin to arterial stiffness. We investigated the impact of visceral adipose tissue (VAT) and HMW adiponectin on cardio-ankle vascular index (CAVI) in asymptomatic Japanese subjects. We studied 487 consecutive subjects (271 men and 216 women) who underwent general health examination between October 2005 and May 2008. The abdominal, visceral, and subcutaneous adipose tissue areas were determined by low-dose x-ray computed tomography. Serum levels of total and HMW adiponectin were measured using the enzyme-linked immunosorbent assay system based on a monoclonal antibody to humans. Cardio-ankle vascular index was positively correlated with VAT area and negatively correlated with HMW adiponectin levels. We also found the positive association of the number of metabolic syndrome components with CAVI in both sexes. A stepwise multiple regression analysis revealed that age, VAT area, serum HMW adiponectin levels, and homeostasis model assessment of insulin resistance were independent determinants of CAVI. Receiver operating characteristic analyses demonstrated that the predictive value of the VAT area for the extent of CAVI (mild: <25th percentile vs severe: >75th percentile) exceeded that of total or HMW adiponectin levels in both sexes. In conclusion, increased CAVI is associated with both amounts of VAT measured by computed tomography and serum HMW adiponectin levels in asymptomatic Japanese subjects. Receiver operating characteristic analysis indicates that the VAT area is a lot better predictor of arterial stiffness than adiponectin levels.

Is there any association between subcutaneous adipose tissue area and plasma total and high molecular weight adiponectin levels

This study was conducted for the purpose of clarifying the correlations between the subcutaneous adipose tissue area and plasma total and high-molecular weight (HMW) adiponectin levels. The subjects of this study comprised 359 men and 142 women who underwent general health examinations from October 2005 to December 2006. The abdominal subcutaneous and visceral adipose tissue areas were measured using low-dose x-ray computed tomography. Total and HMW adiponectin levels were measured using the enzyme-linked immunosorbent assay system based on a monoclonal antibody to humans. There were negative correlations between the plasma total and HMW adiponectin levels and visceral and subcutaneous adipose tissue areas using simple correlation analysis. Multiple linear regression analysis clearly indicated that the subcutaneous adipose tissue area was independently correlated with the HMW adiponectin levels in men and closely related in women. Many studies reported that only the visceral adipose tissue area showed a significant correlation with metabolic syndrome. However, these results clearly indicate that it is also important to consider the subcutaneous adipose tissue area in metabolic syndrome.

Effects of Dabigatran on the Resolution of Left Ventricular Thrombus after Acute Myocardial Infarction

Left ventricular thrombus (LVT) after acute myocardial infarction (AMI) is a risk factor for embolic complications. Although warfarin has traditionally been used to treat LVT, it has relevant disadvantages that limit its use. We herein describe the case of a 78-year-old man with AMI who had a history of paroxysmal atrial fibrillation. Following 10 days of urgent coronary reperfusion therapy, transthoracic echocardiography revealed a moderately sized LVT in the apex, which subsequently disappeared after 18 days of treatment with dabigatran. This case demonstrates that dabigatran may represent an alternative to warfarin as a therapeutic option in patients with LVT after AMI.