Toshiharu Oka

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.

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.

Association Between Aortic Valve Calcification and Myocardial Ischemia, Especially in Asymptomatic Patients

Aortic valve calcification (AVC) is recognized as a manifestation of systemic arteriosclerosis. However, it is unclear whether AVC is associated with myocardial ischemia. Stress myocardial perfusion SPECT (MPS) is widely used for the diagnosis of myocardial ischemia. However, routine MPS is not recommended, particularly in asymptomatic patients. Accordingly, we investigated the hypothesis that the presence of AVC is strongly associated with inducible myocardial ischemia, even among asymptomatic patients. Methods: We investigated 669 consecutive patients who underwent both adenosine stress 201Tl MPS and echocardiography. We evaluated the extent and severity of myocardial ischemia by the summed difference score (SDS). We defined the presence of myocardial ischemia as SDS ≥ 3 and moderate to severe ischemia as SDS ≥ 8. We classified the severity of AVC according to the number of affected aortic leaflets. We also compared the mean SDS and the prevalence of SDS ≥ 3 and SDS ≥ 8 among patients stratified by the severity of AVC. Results: The presence of AVC was significantly associated with myocardial ischemia (odds ratio [OR], 1.56; 95% confidence interval [CI], 1.10–2.23; P = 0.013) and moderate to severe ischemia (OR, 2.16; 95% CI, 1.26–3.80; P = 0.0061). In 311 asymptomatic patients, AVC was strongly associated with moderate to severe ischemia (OR, 4.31; 95% CI, 1.67–12.8; P = 0.0043). However, the SDS value and the prevalence of SDS ≥ 3 and SDS ≥ 8 did not increase with increasing number of affected aortic leaflets. Conclusion: The presence of AVC may be associated with the presence of myocardial ischemia, particularly in asymptomatic patients. However, we found no association between the extent of AVC and inducible myocardial ischemia. The presence of AVC may be a useful anatomic marker to help identify patients at high risk of myocardial ischemia, particularly asymptomatic patients.

Primary cardiac lymphoma diagnosed by endomyocardial biopsy using transthoracic echocardiography in the substernal window

We report a case of a 56-year-old man with a cardiac tumor, which grew and spread rapidly in the right heart. Using transthoracic echocardiography (TTE) in the substernal window, a transvenous biopsy of the tumor was performed safely. The tissue diagnosis revealed a diffuse large B cell lymphoma. After undergoing chemotherapy, the tumor was completely cured and the patient continues to be in good health. A biopsy using TTE in the substernal window may be a useful method to diagnose right-sided extensive tumors.