Masanobu Samukawa

Relationship Between Epicardial Fat Measured by 64-Multidetector Computed Tomography and Coronary Artery Disease

Epicardial fat (EF) is the visceral fat of the heart deposited under the visceral layer of the pericardium and has the same origin as abdominal visceral fat, which is shown to be strongly related to the development of coronary artery disease (CAD). We measured the volume of EF (EFV) by 64‐multidetector computed tomography (MDCT) and studied the relationship between EFV and the severity of CAD.

Prevalence of subclinical atherosclerosis in asymptomatic diabetic patients by 64-slice computed tomography

ObjectivesPatients with diabetes have a 2-fold to 4-fold higher risk of a cardiovascular event than nondiabetic patients. Thus there is a need to identify patients with diabetes who are at risk of cardiovascular events before the onset of symptoms. We studied the prevalence of coronary artery disease in asymptomatic diabetic patients compared with asymptomatic nondiabetic patients by 64-slice computed tomography (CT). MethodsFrom 425 asymptomatic patients with coronary risk factors but without known coronary artery disease who underwent 64-slice CT, we identified 93 asymptomatic diabetic patients (diabetic group) and 93 age-matched and sex-matched asymptomatic nondiabetic patients. ResultsClinical characteristics were not significantly different between the two groups. Total coronary calcium score was significantly higher in diabetic group than that in nondiabetic group (median 117 vs. 53.5, P<0.0001). No coronary calcium was detected in 30.0% of nondiabetic group compared with 15.1% of diabetic group (P=0.0022). Coronary calcium score more than 400 was detected in 9.7% of nondiabetic group compared with 36.6% of diabetic group (P<0.0001). Coronary plaques were found in 67.7% of nondiabetic group compared with 91.4% of diabetic group (P<0.0001). Multiple plaques were detected in 57.0 and 77.4% of patients in nondiabetic and diabetic group, respectively (P=0.0030). Significant coronary stenosis was found in 16.1% of nondiabetic group compared with 33.3% of diabetic group (P=0.0065). ConclusionOur results show that the prevalence of coronary plaques detectable by 64-slice CT in asymptomatic diabetic patients is very high.

Left recurrent laryngeal nerve palsy associated with primary pulmonary hypertension and patent ductus arteriosus

Two patients with left recurrent laryngeal nerve paralysis in association with pulmonary artery hypertension are described. One had primary pulmonary hypertension and the other had patent ductus arteriosus. The greatly dilated pulmonary artery in these patients resulted in compression of the left recurrent laryngeal nerve and produced a cardiovocal (Ortners) syndrome. The pathogenesis of the vocal cord palsy was documented by cross-sectional computed tomography. In conclusion, computed tomography is of great help in differentiating this syndrome from other diseases such as mediastinal mass or lymphadenopathy whenever hoarseness is complicated by pulmonary hypertension.

Distribution of coronary atherosclerosis in patients with coronary artery disease

The distribution of coronary atherosclerosis has not been fully clarified. We measured coronary artery calcium score (CACS) in 624 consecutive patients for the right coronary artery (RCA), left main trunk (LMT), left anterior descending coronary artery (LAD), and left circumflex coronary artery (LCx), then calculated total CACS. Coronary artery calcium score was measured using the Agatston method. We divided these patients into four groups: CACS 1–100 (Group A, n = 267), CACS 101–400 (Group B, n = 160), CACS 401–1000 (Group C, n = 110), and CACS >1000 (Group D, n = 87). In Group A, B, and C, the CACS in LAD was significantly higher than in the other three arteries (P < 0.0001). In Group D, the CACS was not significantly different between LAD and RCA (P = 0.6930). In Groups A, B, and C, coronary artery calcium (CAC) was more frequently found in LAD compared with other arteries (P < 0.0001). However, in Group D the prevalence of CAC was not significantly different among the three arteries (P = 0.4435). Coronary artery calcium was found more frequently in LAD than in the other coronary arteries in patients with mild to high CAC, but not in those with very high CAC.

Prevalence of subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk by 64-slice computed tomography

BackgroundRecent research has shown that cardiovascular risk scoring significantly underestimates or misclassifies risk in key subsets of the population. There is a growing need for a noninvasive imaging to detect a subclinical atherosclerosis. Thus we hypothesized that 64-slice computed tomography (CT) could effectively detect subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk. MethodsFour hundred and fifteen asymptomatic patients with coronary risk factors underwent 64-slice CT. When 64-slice CT showed a significant stenosis we recommended that patients receive stress myocardial perfusion imaging (MPI). When MPI showed ischemic findings, we recommended that patients receive a coronary revascularization procedure. We followed our patients for a mean of 2.8 years (2.4–3.3 years). ResultsWe detected coronary plaques in 295 patients (71.1%). Of 135 patients with a negative scan for coronary calcification, noncalcified plaques were detected in 15 patients (11.1%). Two hundred and thirty-five patients (79.7%) had multiple plaques and, on average, one patient had 4.6 plaques. Significant coronary stenosis was detected in 91 patients (21.9%) and 85 patients underwent stress MPI. Myocardial ischemia was found in 27 patients (31.8%) and 21 patients underwent percutaneous coronary intervention. For a mean follow-up period of 2.8 years, four patients developed acute coronary syndrome. ConclusionOur results showed that the prevalence of subclinical atherosclerosis in asymptomatic patients with low-to-intermediate risk was very high and one-fifth of them had significant stenosis as shown by 64-slice CT. However, myocardial ischemia was detected in only one-third of them.

Prevalence of noncalcified coronary plaque on 64-slice computed tomography in asymptomatic patients with zero and low coronary artery calcium

OBJECTIVES To study the prevalence of noncalcified plaque in asymptomatic low-risk patients with no or mild coronary artery calcium (CAC). METHODS From 502 patients with coronary risk factors who underwent 64-slice computed tomography, 224 asymptomatic patients were identified with no CAC (n=117) or mild CAC (n=107; defined as patients with Agatston scores from 1 to 100). RESULTS Patients with no CAC were younger and had diabetes less often. Medications and laboratory data were not significantly different between the two groups. The prevalence of noncalcified plaque was 11.1% in patients with no CAC and 23.4% in the mild CAC group (P=0.0142). Multiple plaques were detected in 2.6% of the group with no CAC and 3.7% of the group with mild CAC (P=0.5934). Significant coronary artery stenosis was found in one patient in the group with no CAC (0.9%) and three patients in the group with mild CAC (2.8%, P=0.3506). CONCLUSIONS Significant percentages of noncalcified plaque were found in asymptomatic low-risk patients with no or mild coronary calcium.

Prevalence of coronary artery disease in asymptomatic patients with abnormal intima-media thickness by 64-slice computed tomography

Abstract We studied the prevalence of subclinical coronary artery disease in 100 asymptomatic patients with abnormal intima-media thickness (IMT) by 64-slice computed tomography (CT). Coronary calcium was detected in 74.0% of patients and coronary plaque was detected in 77.0% of patients. Our results showed that the prevalence of coronary artery disease in asymptomatic patients with abnormal IMT was very high.

Significant coronary artery disease detected by amyl nitrite and systolic time intervals

The relation between changes in left ventricular systolic time intervals with amyl nitrite (AN) inhalation and the severity of coronary artery disease (CAD) was evaluated in 77 patients who underwent catheterization because of chest pain. In 25 subjects with normal coronary angiograms (control group), AN inhalation increased the ejection time (ET), shortened the preejection period (PEP) and increased the ET/PEP markedly. In the 52 patients with CAD (CAD group), the ET/PEP changed insignificantly after AN. The difference between the 2 groups was significant (p less than 0.001). At cardiac catheterization, the increase of left ventricular dP/dt after AN in the control group was significantly larger than that in the CAD group. Although a positive correlation between changes in ET/PEP with AN and ejection fraction at rest was noted in patients with 1-vessel CAD, no such correlation was noted in those with multivessel CAD. This suggests that factors in addition to pump function, such as the degree of CAD, influence the effect of AN inhalation on systolic time intervals. When an increase of less than 30% in ET/PEP occurs with AN inhalation, the presence of significant CAD can be detected with a sensitivity of 92%, a specificity of 84% and the predictive value of 92%. The AN inhalation test is safe and simple, and thus could serve as a stress test for evaluating the presence and severity of significant CAD.

Electrocardiographic features differentiating dilated cardiomyopathy from hypertrophic cardiomyopathy

To determine the usefulness of electrocardiographic (ECG) features in differentiating between hypertrophic cardiomyopathy with features mimicking dilated cardiomyopathy (D-HCM) and true dilated cardiomyopathy (DCM), we compared ECGs of 52 consecutive patients (11 with D-HCM, 41 with DCM). Left atrial dimension, left ventricular internal dimension, and septal and posterior wall thickness were employed as echocardiographic indexes, while QRS duration, amplitude of RV5 or V6 + SV1, number of abnormal Q waves, P-terminal force in V1, and frontal plane QRS axis were used as ECG parameters. The patients with D-HCM demonstrated a larger number of abnormal Q waves (P < .0001), greater prolongation of QRS duration (P < .0001), and lower amplitude of RV5 or V6 + SV1 (P < .0001). In all cases of D-HCM, atrial overload was observed and abnormal QRS axis in 9 (82%) of the 11 patients. These features were noted in 21 (51%) and 17 (41%), respectively, of the 41 DCM patients (P < .005 and P < .05, respectively). Despite significant differences in the echocardiographic parameters between D-HCM and DCM, excluding left ventricular end-diastolic dimension, ECG abnormalities were more significant between the two groups. The results indicate that ECG features are extremely useful in differentiation between DCM and D-HCM.

Right ventricular outflow obstruction secondary to post-infarction aneurysm: A possible new syndrome

SummaryTwo patients with extensive anterior myocardial infarction developed a hitherto unreported type of right ventricular outflow tract obstruction. A 71-year-old woman, who had had an acute infarction 10 years before, was admitted for sustained ventricular tachycardia. A loud ejection murmur was heard in the mid-precordium. The echocardiogram and left ventriculogram showed a septal aneurysm, with a systolic gradient of 21 mmHg between the right ventricular outflow tract and apex. The ejection murmur was detected in the outflow tract by intracardiac phonocardiography. The second patient was a 60-year-old man who had had an acute infarction at age 47. He was also referred because of ventricular tachycardia, and his clinical situation was almost the same as that of the first case. Our search of the literature failed to disclose any similar case with a loud ejection murmur confirmed by intracardiac phonocardiography to be due to an obstructive septal aneurysm.