Sei Komatsu

Randomized Comparison of 64-Slice Single- and Dual-Source Computed Tomography Coronary Angiography for the Detection of Coronary Artery Disease

OBJECTIVES The purpose of this study was to analyze the influence of a systematic approach to lower heart rate for coronary computed tomography (CT) angiography on diagnostic accuracy of 64-slice single- and dual-source CT. BACKGROUND Coronary CT angiography is often impaired by motion artifacts, so that routine lowering of heart rate is usually recommended. This is often conceived as a major limitation of the technique. It is expected that higher temporal resolution, such as with dual-source 64-slice CT, would allow diagnostic imaging even without systematic pre-treatment for lowering the heart rate. METHODS Two hundred patients with suspected coronary artery disease were first randomized to either 64-slice single-source CT (n = 100) or dual-source CT (n = 100) for contrast-enhanced coronary artery evaluation. In each group, patients were further randomized to either receive systematic heart rate control (oral and intravenous beta-blockade for a target heart rate < or =60 beats/min) or receive no premedication. Evaluability of datasets and diagnostic accuracy were compared between groups against the results obtained from invasive angiography. RESULTS Systematic pre-treatment lowered heart rate during CT coronary angiography by 10 beats/min. Heart rate control significantly improved evaluability in single-source CT (93% vs. 69% on a per-patient basis, p = 0.005), whereas it did not in dual-source CT (96% vs. 98%). In evaluable patients, sensitivity to detect the presence of at least 1 coronary stenosis by single-source CT was 86% and 79%, respectively, with and without heart rate control (p = NS). For dual-source CT, it was 100% and 95%, respectively (p = NS). The rate of correctly classified patients, defined as evaluable and correct classification as to the presence or absence of at least 1 coronary artery stenosis, was significantly improved by heart rate control in single-source CT (78% vs. 57%, p = 0.04), whereas there was no such influence in dual-source CT (87% vs. 93%). CONCLUSIONS Systematic heart rate control significantly improves image quality for coronary visualization by 64-slice single-source CT, whereas image quality and diagnostic accuracy remain unaffected in dual-source CT angiography. Improved temporal resolution obviates the need for heart rate control.

Assessment of changes in non-calcified atherosclerotic plaque volume in the left main and left anterior descending coronary arteries over time by 64-slice computed tomography.

Multidetector computed tomography (MDCT) permits the visualization of the coronary arteries and of coronary atherosclerotic plaques. The natural course of noncalcified plaque is not known. This study was conducted to measure the change in noncalcified coronary plaque volume in the left main coronary artery and in the proximal left anterior descending coronary artery over time using 64-slice MDCT. Fifty patients in whom noncalcified lesions had been detected on baseline MDCT received follow-up scans after an interval of 17 +/- 6 months. Plaque areas were traced manually in serial multiplanar reconstructions to determine overall volume. The mean plaque volumes were 92 +/- 81 mm(3) on baseline MDCT and 115 +/- 110 mm(3) on follow-up MDCT (p <0.001). The mean annualized volume change was 22% (95% confidence interval 14.7% to 29.7%). A weak but significant correlation with low-density lipoprotein cholesterol level was observed for the amount of baseline plaque volume (r = 0.37, p <0.001). In conclusion, the quantification of noncalcified plaque volume is possible on repeated 64-slice MDCT. A significant increase of the amount of noncalcified plaque was observed over a mean interval of 17 months. Contrast-enhanced MDCT may therefore be a tool to study the progression of coronary atherosclerosis.

Anomalous coronary arteries in adults detected by multislice computed tomography: presentation of cases from multicenter registry and review of the literature

Anomalous coronary arteries are a rare condition, but they may cause myocardial ischemia, heart failure, and sudden death. We evaluated the prevalence and multislice computed tomographic (MSCT) findings of anomalous coronary arteries in a large number of patients from the multicenter registry. At four institutes, 29 (0.74%) out of 3910 patients were found to have anomalous coronary arteries by MSCT. They consisted of 15 patients with anomalous origins of the right coronary artery, 1 with right-sided origin of the left circumflex artery, 1 with right-sided origin of the left main coronary artery, 2 with double right coronary arteries, 2 with the absence of the left circumflex artery, 1 with absence of the right coronary artery, 6 with coronary artery fistulas, and 1 with Bland-White-Garland syndrome. Multislice computed tomography findings were consistent with those obtained by conventional coronary angiography in all 14 patients undergoing both diagnostic procedures. Multislice computed tomography permits three-dimensional comprehension of coronary arteries, which is suitable for the diagnosis of anomalous coronary arteries.

Visceral abdominal fat accumulation predicts the progression of noncalcified coronary plaque.

BACKGROUND Excess visceral abdominal tissue (VAT) is more strongly associated with risk factors of coronary artery disease (CAD) than body mass index (BMI) or waist circumference. However, whether adding VAT measurements to CAD risk factors provides better risk assessment for CAD progression has not been fully evaluated. METHODS AND RESULTS This prospective cohort study comprised 553 CAD patients with coronary plaque with ≤50% coronary stenosis as assessed by computed tomography (CT) angiography. Quantification of VAT area was performed together with CT angiography using abdominal CT scanning. After a mean 38±8 months follow-up, 320 patients underwent repeated CT scans for worsening angina symptoms without findings of positive ischemia. Increased segments of noncalcified plaque were seen in 152 (48%) and an increased calcium score was seen in 261 (82%) patients. The risk for progression of noncalcified plaque increased steadily with higher VAT quartiles, independent of CAD risk factors. Patients in the higher quartiles were at increased risk of progression of noncalcified plaque (quartiles IV OR 4.7; 95% CI 2.3-9.4, p-value<0.001). In contrast, increases above the median calcium score showed no independent correlation to VAT. Compared to VAT, progression of noncalcified plaque showed no phased increase with higher waist circumference and weaker increase with higher BMI quartiles. CONCLUSION VAT accumulation was positively associated with progression of coronary noncalcified plaque, but not of calcified plaque. This suggests that risk assessment of progression of noncalcified plaque can be improved by combining VAT measurements and CAD risk factors.

Serum cystatin C is associated with early stage coronary atherosclerotic plaque morphology on multidetector computed tomography

OBJECTIVE Cystatin C, a novel marker of kidney function, has been reported to be a predictor of adverse cardiovascular outcomes in patients without established chronic kidney disease. However, the relationship between serum cystatin C concentrations and early stage coronary atherosclerotic plaque morphology among patients with preserved kidney function has not been fully evaluated. METHODS AND RESULTS 405 outpatients with early coronary artery disease with estimated glomerular filtration rate (eGFR) ≥ 60ml/min/1.73m(2) and <50% stenosis on 64-slice CT coronary angiography were enrolled. Subjects were categorized into quartiles by serum cystatin C (quartile I: ≤ 0.88mg/L - quartile IV: ≥ 1.16mg/L). Plaques in coronary segments were categorized as calcified or noncalcified. Multiple linear regression analysis revealed that lower eGFR, higher age, increasing numbers of noncalcified and calcified plaques, lower high-density lipoprotein cholesterol, and female gender were statistically significant predictors of increased cystatin C concentrations. The risk for presence of noncalcified plaques increased significantly with increasing quartiles of cystatin C. Compared with those in the lowest quartile, patients in each subsequent quartile were at steadily increased risk of having noncalcified plaque (quartile IV: OR 5.6; 95% CI 2.3-13.9, p-value <0.001). Both number of segments with calcified plaque and Agatston score were highly correlated with cystatin C concentrations (both p<0.001), but when adjusted for segments with noncalcified plaque and other risk factors, calcified plaque segments were no longer independently predictive. CONCLUSION Higher serum cystatin C concentrations were correlated with early stage coronary atherosclerotic plaques among patients without established chronic kidney dysfunction. Noncalcified plaques increased with serum cystatin C concentrations, an association independent of eGFR and other cardiovascular risk factors.

Multislice computed tomographic findings of the anomalous origins of the right coronary artery: evaluation of possible causes of myocardial ischemia

BackgroundAnomalous right coronary arteries (RCA) arising from the left sinus of Valsalva may cause myocardial ischemia.ObjectiveWe evaluated morphological features of anomalous RCA by using multislice computed tomography (MSCT) in relation to myocardial ischemia provoked by myocardial perfusion single-photon emission computed tomography.MethodsMSCT was performed in a total of 3, 212 patients by using an Aquillion 16 and a Light Speed Ultra. Retrospective ECG-gated image reconstruction was performed. Volume rendering, axial and curved multiplanar reformatted images were analyzed for the determination of the origin and course of the RCA, the take-off angle of the RCA from the aorta, and size of the RCA orifice. Furthermore, virtual angioscopic images were also used for the evaluation of the RCA orifice structure.ResultsAnomalous origins of the RCA were found in 15 patients. In 13 patients, the RCA arose from the left sinus of Valsalva, and in 2 patients it arose from the left main coronary artery as a single coronary artery. The RCA coursed anteriorly between the ascending aorta and pulmonary artery in 14 patients, whereas it had a retroaortic course in 1 patient. Acute angle take-off (<30°) of the RCA from the aorta and the left main coronary artery was observed in 8 patients, intramural course of the RCA within the aortic wall was observed in 6 patients and a small RCA orifice was observed in 4 patients. Exercise-induced myocardial ischemia was present in 5 patients.ConclusionCoursing between the aorta and pulmonary artery, acute angle take-off and intramural course were thought to be major causes of exercise-induced ischemia in patients with anomalous origins of the RCA.

Plaque stabilization by intensive LDL-cholesterol lowering therapy with atorvastatin is delayed in type 2 diabetic patients with coronary artery disease—Serial angioscopic and intravascular ultrasound analysis

BACKGROUND Diabetes mellitus (DM) is a major risk factor for cardiovascular events. The study purpose was to compare DM and non-DM (nDM) patients in terms of statin-induced change of plaque characteristics using intravascular ultrasound (IVUS) and coronary angioscopy. METHODS Patients with coronary artery disease and hypercholesterolemia who were enrolled to the TWINS were selected and classified into two groups: DM group and nDM group. Eleven DM patients and 28 nDM patients were studied. RESULTS Low-density lipoprotein cholesterol levels decreased significantly to a similar extent at weeks 28 and 80 from baseline in DM and nDM (p<0.001). The mean angioscopic color grades of yellow plaques in DM and nDM were similar at baseline and significantly decreased at week 80 from baseline in both groups, however, the mean change of angioscopic color grade from baseline in DM were not significantly decreased and the mean angioscopic color was significantly higher than that in nDM (1.34 vs. 1.00, p<0.05) at week 28. IVUS showed plaque volume reduction in both groups (p<0.01) except at week 80 in DM group, which was not statistically significant different compared to the baseline. CONCLUSION In DM patients, plaque volume regression by atorvastatin was shown to be attenuated, and its color improvement was significantly delayed. However, the yellowness became comparable between DM and nDM groups at week 80. These results indicate that patients with DM should be treated by intensive lipid-lowering therapy with atorvastatin for at least 80 weeks to stabilize vulnerable plaque.

Evaluation of the cavotricuspid isthmus and right atrium by multidetector-row computed tomography in patients with common atrial flutter.

The sizes of the right atrium (RA), cavotricuspid isthmus, and Eustachian valve are predictors of success of radiofrequency catheter ablation for atrial flutter (AFL). We examined the relationship between the sizes of cavotricuspid isthmus as measured by multidetector-row computed tomography (MDCT) and fluoroscopy. We used eight-detector MDCT to measure the tricuspid isthmus of 23 patients prior to linear ablation for common AFL. One patient with a deep pouch in the RA was excluded. Parameters measured were (1) the length of the trace of isthmus (Ti), which was equivalent to the blocking line; (2) the size of the tricuspid isthmus (DTi); and (3) the distance from the tricuspid valve and inferior vena cava (IVC) (LDTi). DTi and LDTi indicate the size of the RA, reflecting the appropriately sized steerable ablation catheter, respectively. Of the 22 patients, 21 were ablated successfully without recurrence of AFL, and clinical success was achieved in one additional patient despite failure to obtain a bidirectional block. Ti, DTi, and LDTi were correlated with fluoroscopy time (r = 0.84, r = 0.88, and r = 0.88, respectively; P < 0.0001), total delivered energy (r = 0.81, r = 0.80, and r = 0.83, respectively; P < 0.0001), and application time (r = 0.84, r = 0.80, and r = 0.87, respectively; P < 0.0001). Measurement of the tricuspid isthmus by MDCT may noninvasively provide important information for successful linear ablation.

Erratum to: Remodeling pattern is related to the degree of coronary plaque regression induced by pitavastatin: a sub-analysis of the TOGETHAR trial with intravascular ultrasound and coronary angioscopy

This study aimed to clarify the relationships between arterial remodeling patterns and plaque volume regression or stabilization. The TOGETHAR trial is a prospective open-label trial designed to assess coronary plaque regression and stabilization with multiple plaque imaging modalities following 52 weeks of pitavastatin treatment (2 mg/day). Coronary plaques were observed in 46 patients with both angioscopy and intravascular ultrasound at baseline and after 52 weeks of drug treatment. We divided these patients into three groups according to their remodeling indices (RI). Group P consisted of patients with a baseline RI >1.05, Group M of patients with a baseline RI of 0.95–1.05, and Group N of patients with a baseline RI <0.95 and then evaluated differences in coronary plaque volume changes and yellow grade among the three groups. In the positive remodeling group, whose remodeling index (RI) exceeded 1.05 at baseline, RI and percent atheroma volume (PAV) were significantly reduced (RI 1.14 ± 0.07 to 1.05 ± 0.10, p = 0.010, PAV 47.3 ± 8.3 to 45.3 ± 7.3 mm3, p = 0.048). There was no relationship between baseline RI and the change in yellow grade of plaque. RI increased without significant change of PAV or a decrease in lumen volume in group N, with RI below 0.95 at baseline. Plaques with positive remodeling were more likely to have plaque volume regression by pitavastatin than those without in patients with coronary artery disease. Moreover, plaques with positive and negative remodeling were changed into those with intermediate remodeling by pitavastatin. Pitavastatin might induce not only plaque regression or stabilization, but also conformational normalization of vessel structure.

Nonobstructive angioscopy in patient with atherosclerotic renal artery stenosis

Few applications of angioscopy for evaluating atherosclerosis of the abdominal aorta have been described. We report the demonstration of atherosclerotic yellow plaque by nonobstructive angioscopy in a patient with left renal artery stenosis. Computed tomography angiography showed stenosis in one of the left renal arteries in a 65-year-old man who presented with renal impairment and hypertension. Invasive selective renal angiography indicated severe stenosis in the proximal portion of the inferior left renal arteries. Intravascular ultrasound demonstrated eccentric plaque with predominant low-density plaque with calcification as the culprit. Percutaneous transluminal renal angioplasty with stent implantation of the left renal artery was performed. Nonobstructive angioscopy demonstrated a grade 3 yellow culprit plaque at the proximal end of the stent, and grade 2 and grade 1 yellow plaques as the culprit plaques at the middle and distal portions of the artery, respectively. <Learning objective: Atherosclerotic renal artery stenosis characterized by lipid-rich plaque and yellow plaque was diagnosed by intravascular imaging, such as intravascular ultrasound and angioscopy. As the stenosis was hemodynamically significant, percutaneous transluminal renal angioplasty was successfully performed. Nonobstructive angioscopy may be potentially applied for monitoring of transluminal ablation of the renal artery sympathetic nerves during drug-resistant hypertension.>.