Masayoshi Sarai

Computed tomographic angiography characteristics of atherosclerotic plaques subsequently resulting in acute coronary syndrome.

OBJECTIVES In a computed tomographic (CT) angiography study, we identified the characteristics of atherosclerotic lesions that were associated with subsequent development of acute coronary syndrome (ACS). BACKGROUND The CT characteristics of culprit lesions in ACS include positive vessel remodeling (PR) and low-attenuation plaques (LAP). These 2 features have been observed in the lesions that have already resulted in ACS, but their prospective relation to ACS has not been previously described. METHODS In 1,059 patients who underwent CT angiography, atherosclerotic lesions were analyzed for the presence of 2 features: PR and LAP. The remodeling index, and plaque and LAP areas and volumes were calculated. The plaque characteristics of lesions resulting in ACS during the follow-up of 27 +/- 10 months were evaluated. RESULTS Of the 45 patients showing plaques with both PR and LAP (2-feature positive plaques), ACS developed in 10 (22.2%), compared with 1 (3.7%) of the 27 patients with plaques displaying either feature (1-feature positive plaques). In only 4 (0.5%) of the 820 patients with neither PR nor LAP (2-feature negative plaques) did ACS develop. None of the 167 patients with normal angiograms had acute coronary events (p < 0.001). ACS was independently predicted by PR and/or LAP (hazard ratio: 22.8, 95% confidence interval: 6.9 to 75.2, p < 0.001). Among 2- or 1-feature positive segments, those resulting in ACS demonstrated significantly larger remodeling index (126.7 +/- 3.9% vs. 113.4 +/- 1.6%, p = 0.003), plaque volume (134.9 +/- 14.1 mm(3) vs. 57.8 +/- 5.7 mm(3), p < 0.001), LAP volume (20.4 +/- 3.4 mm(3) vs. 1.1 +/- 1.4 mm(3), p < 0.001), and percent LAP/total plaque area (21.4 +/- 3.7 mm(2) vs. 7.7 +/- 1.5 mm(2), p = 0.001) compared with segments not resulting in ACS. CONCLUSIONS The patients demonstrating positively remodeled coronary segments with low-attenuation plaques on CT angiography were at a higher risk of ACS developing over time when compared with patients having lesions without these characteristics.

Serial Coronary CT Angiography–Verified Changes in Plaque Characteristics as an End Point: Evaluation of Effect of Statin Intervention

OBJECTIVES This study sought to assess, by serial computed tomography angiography (CTA), the effect of statin treatment on coronary plaque morphology. BACKGROUND In addition to the assessment of luminal stenosis, CTA also allows characterization of plaque morphology. Large, positively remodeled plaques with large necrotic cores have been reported as indicators of plaque instability. METHODS CTA was performed in 32 patients (26 men, ages 64.3 +/- 8.5 years). Of these, 24 received fluvastatin after the baseline study; 8 subjects who refused statin treatment were followed as the control subjects. Serial imaging was performed after a median interval of 12 months. All vessels were examined in every subject, and a 10-mm-long segment was identified for comparison before and after intervention. Total plaque volume, low attenuation plaque (LAP) volume, lumen volume, and remodeling index were calculated. RESULTS In the statin-treated patients, the total plaque volume (92.3 +/- 37.7 vs. 76.4 +/- 26.5 mm(3), p < 0.01) and LAP volume (4.9 +/- 7.8 vs. 1.3 +/- 2.3 mm(3), p = 0.01) were significantly reduced over time; however, there was no change in the lumen volume (63.9 +/- 25.3 vs. 65.2 +/- 26.2 mm(3), p = 0.59). On the other hand, no change was observed in the CTA characteristics in the control subjects, including total plaque volume (94.4 +/- 21.2 vs. 98.4 +/- 28.6 mm(3), p = 0.48), LAP volume (2.1 +/- 3.0 vs. 2.3 +/- 3.6 mm(3), p = 0.91), and lumen volume (80.5 +/- 20.7 vs. 75.0 +/- 16.3 mm(3), p = 0.26). The plaque volume change (-15.9 +/- 22.2 vs. 4.0 +/- 14.0 mm(3), p = 0.01) and LAP volume change (-3.7 +/- 7.0 vs. 0.2 +/- 1.5 mm(3), p < 0.01) were significantly greater in the statin than the control group. The lumen volume (1.3 +/- 15.6 vs. -5.5 +/- 13.1 mm(3), p = 0.24) and remodeling index (-2.4 +/- 6.8% vs. -0.3 +/- 6.5%, p = 0.53) did not show the significant differences between the 2 groups. The decrease in the plaque volume was due to reduction in the LAP volume (R = 0.83, p < 0.01), and was not related to any changes in the lumen volume (R = 0.21, p = 0.24). CONCLUSIONS This preliminary study suggests that serial CTA evaluation of coronary plaques allows for the assessment of interval change in the plaque morphology. Statin treatment results in decreases in the plaque and necrotic core volume. The features known to be associated with plaque instability.

Original ResearchSerial Coronary CT Angiography–Verified Changes in Plaque Characteristics as an End Point: Evaluation of Effect of Statin Intervention

OBJECTIVES This study sought to assess, by serial computed tomography angiography (CTA), the effect of statin treatment on coronary plaque morphology. BACKGROUND In addition to the assessment of luminal stenosis, CTA also allows characterization of plaque morphology. Large, positively remodeled plaques with large necrotic cores have been reported as indicators of plaque instability. METHODS CTA was performed in 32 patients (26 men, ages 64.3 +/- 8.5 years). Of these, 24 received fluvastatin after the baseline study; 8 subjects who refused statin treatment were followed as the control subjects. Serial imaging was performed after a median interval of 12 months. All vessels were examined in every subject, and a 10-mm-long segment was identified for comparison before and after intervention. Total plaque volume, low attenuation plaque (LAP) volume, lumen volume, and remodeling index were calculated. RESULTS In the statin-treated patients, the total plaque volume (92.3 +/- 37.7 vs. 76.4 +/- 26.5 mm(3), p < 0.01) and LAP volume (4.9 +/- 7.8 vs. 1.3 +/- 2.3 mm(3), p = 0.01) were significantly reduced over time; however, there was no change in the lumen volume (63.9 +/- 25.3 vs. 65.2 +/- 26.2 mm(3), p = 0.59). On the other hand, no change was observed in the CTA characteristics in the control subjects, including total plaque volume (94.4 +/- 21.2 vs. 98.4 +/- 28.6 mm(3), p = 0.48), LAP volume (2.1 +/- 3.0 vs. 2.3 +/- 3.6 mm(3), p = 0.91), and lumen volume (80.5 +/- 20.7 vs. 75.0 +/- 16.3 mm(3), p = 0.26). The plaque volume change (-15.9 +/- 22.2 vs. 4.0 +/- 14.0 mm(3), p = 0.01) and LAP volume change (-3.7 +/- 7.0 vs. 0.2 +/- 1.5 mm(3), p < 0.01) were significantly greater in the statin than the control group. The lumen volume (1.3 +/- 15.6 vs. -5.5 +/- 13.1 mm(3), p = 0.24) and remodeling index (-2.4 +/- 6.8% vs. -0.3 +/- 6.5%, p = 0.53) did not show the significant differences between the 2 groups. The decrease in the plaque volume was due to reduction in the LAP volume (R = 0.83, p < 0.01), and was not related to any changes in the lumen volume (R = 0.21, p = 0.24). CONCLUSIONS This preliminary study suggests that serial CTA evaluation of coronary plaques allows for the assessment of interval change in the plaque morphology. Statin treatment results in decreases in the plaque and necrotic core volume. The features known to be associated with plaque instability.

Coronary CT angiographic characteristics of culprit lesions in acute coronary syndromes not related to plaque rupture as defined by optical coherence tomography and angioscopy.

AIMS Pathological and clinical optical coherence tomography (OCT) studies have indicated that acute coronary syndrome (ACS) lesions have either ruptured fibrous caps (RFC-ACS) or intact fibrous caps (IFC-ACS). Although computed tomographic (CT) angiographic characteristics of RFC-ACS include low-attenuation plaques and positive plaque remodelling, features associated with IFC-ACS have not been previously described. The aim of this study was to assess the CT characteristics of IFC-ACS lesions. METHODS AND RESULTS Seventy-four patients with ACS/stable angina consented to multimodality imaging, of which 66 underwent CT angiography. Of these, 57 culprit lesions in 57 patients were evaluated with sufficient image quality from all four of OCT, angioscopy, intravascular ultrasound, and CT angiography. Intraluminal thrombus was assessed by OCT/angioscopy, and culprit lesions further classified by OCT-based demonstration of fibrous cap integrity. Of 35 culprit lesions with ACS, OCT revealed IFC with thrombus in 10 (29%) and RFC in the remaining 25 (71%); all 22 lesions with stable angina had intact fibrous caps. Fibrous caps were significantly thinner in RFC-ACS than IFC-ACS and stable angina (45 ± 12, 131 ± 57, and 321 ± 146 μm, respectively; P = 0.001). CT angiography revealed that low-attenuation plaques were more frequently observed in RFC-ACS than IFC-ACS and stable angina (88, 40, and 18%; P = 0.001) lesions. Similarly, positive remodelling was more predominantly seen in RFC-ACS than IFC-ACS and stable angina (96, 20, and 14%; P = 0.001). However, none of the specific CT angiography features clearly distinguished IFC-ACS from stable lesions. CONCLUSION In contrast to the situation with RFC-ACS, distinct culprit lesion characteristics associated with non-rupture-related mechanisms are not identified by CT angiography. It will therefore not be possible to differentiate plaques likely to develop IFC-ACS from stable plaques.

Noninvasive Coronary Angiography With a Prototype 256-Row Area Detector Computed Tomography System Comparison With Conventional Invasive Coronary Angiography

To the Editor: Since the initial reports describing the usefulness of computed tomography angiography (CTA) with 4-row multislice compute tomography (MSCT) for the examination of the coronary arteries, the number of detector rows has been further increased. Now, 256-row area detector CT (256-row CT

Evaluation of Probable or Possible Dementia with Lewy Bodies Using 123I-IMP Brain Perfusion SPECT, 123I-MIBG, and 99mTc-MIBI Myocardial SPECT

We evaluated the diagnostic usefulness of combination studies with a statistical mapping method in N-isopropyl-p-123I-iodoamphetamine (123I-IMP) brain perfusion SPECT, cardiac sympathetic nerve function by 123I-metaiodobenzylguanidine (123I-MIBG), and myocardial function by electrocardiographically gated 99mTc-sestamibi (99mTc-MIBI) SPECT for patients with probable or possible dementia with Lewy bodies (DLB). Methods: Twelve patients with probable DLB (7 male, 5 female; mean age ± SD, 72.3 ± 5.63 y; range, 65–82 y) and 9 patients with possible DLB (3 male, 6 female; mean age ± SD, 73.1 ± 9.23 y; range, 59–88 y) were enrolled in this study. 123I-IMP SPECT images were analyzed with 3-dimensional stereotactic surface projections (3D-SSP) and the severity of ischemia was classified objectively using quantitatively analytic and display software; stereotactic extraction estimation (SEE) methods were compared with a normal database. In addition, we evaluated 123I-MIBG heart-to-mediastinum (H/M) uptake ratios. Moreover, we performed 99mTc-MIBI SPECT to evaluate myocardial perfusion and the left ventricular ejection fraction (LVEF) compared with a normal database. Results: 3D-SSP images of group comparison with healthy control subjects showed significantly decreased perfusion in the parietotemporal, occipital cortex, posterior cingulated, and precuneus regions in the probable DLB group but no significant reduction in the possible DLB group. Mean H/M ratios in the probable DLB group were significantly lower than those of the possible DLB group and the control group, respectively. Ten of 12 patients (83.3%) with probable DLB and 1 of 9 patients (11.1%) with possible DLB showed severe reduction in the bilateral occipital lobe and also a low 123I-MIBG uptake. One patient (8.3%) with probable DLB and 2 patients (22.2%) with possible DLB showed no bilateral occipital hypoperfusion but showed low 123I-MIBG uptake. One patient (8.3%) with probable DLB and 6 patients (66.7%) with possible DLB showed no occipital hypoperfusion and normal 123I-MIBG uptake. 99mTc-MIBI gated SPECT did not indicate any wall motion abnormality in any subjects. Conclusion: These results suggest that combined examination of cerebral blood flow with 3D-SSP and SEE analysis, and cardiac sympathetic nerve function with 123I-MIBG, would be a useful supporting diagnostic method in patients with DLB—particularly, in possible DLB and when cerebral blood flow does not indicate occipital hypoperfusion.

Characteristics of plaque progression detected by serial coronary computed tomography angiography

We previously reported that serial coronary computed tomography angiography (CTA) had a potential to evaluate the interval change of plaque morphology of coronary arteries. The aim of this study was to evaluate variables associated with the plaque progression by serial CTA. We included 148 patients (age 66.3 ± 9.8 years, male 81.1 %, median scan interval 12 months) with coronary artery disease undergoing serial CTA. Each coronary artery was compared visually between baseline and follow-up CTA to detect plaque progression. Baseline characteristics between progression and nonprogression patients did not demonstrate any significant differences. Logistic analysis revealed that only low-density lipoprotein cholesterol (LDL-C) ≥100 mg/dl at follow-up was associated with plaque progression (odds ratio 2.59, 95 % confidence interval 1.12–6.34, P = 0.0263). Cutoff value of LDL-C for plaque progression at follow-up was 103.0 mg/dl based on receiver-operator characteristic curves analyses. Of the 36 progressive lesions in 32 patients, plaque composition at baseline included 13 lesions (36.1 %) of noncalcified plaque, 1 lesion (2.8 %) of calcified plaque, 12 lesions (33.3 %) of partially calcified plaque, and the remaining 10 lesions (27.8 %) had no plaque at baseline and revealed de novo plaques at follow-up. There were 9 lesions (25 %) with high-risk plaque (HRP) characteristics at baseline and 18 lesions (50 %) with HRP at follow-up. Plaque progression of coronary arteries by serial CTA was associated with LDL-C ≥100 mg/dl at follow-up regardless of baseline LDL-C level. There was no specific finding to predict plaque progression on the baseline plaque characteristics.

Two cases with past Kawasaki disease developing acute myocardial infarction in their thirties, despite being regarded as at low risk for coronary events

Two patients after Kawasaki disease (KD) developed acute myocardial infarction in their thirties, though coronary artery follow-up were deemed unnecessary because of apparently angiographic normal coronary arteries in their children more than 1-year after acute KD. Angiographic findings of apparently normal coronary arteries in the late period after acute KD are possible to mislead their prognoses. It should be recognized that coronary aneurysms can often regress in the late period. There is ongoing controversy about the therapeutic strategy in patients whose coronary aneurysms regressed within several years after acute KD. Coronary computed tomography angiography and flow-mediated dilatation might be useful for the detection of mild sequelae of KD non-invasively.

Major bleeding complications related to combined antithrombotic therapy in atrial fibrillation patients 12 months after coronary artery stenting

BACKGROUND AND PURPOSE Many patients with atrial fibrillation (AF) and coronary artery stent deployment are given both antiplatelet drug and warfarin. Little information is available as to the relationship between the antithrombotic therapies in the late phase after stenting and the clinical outcomes of these patients. We examined the clinical outcomes of AF patients 12 months after coronary artery stenting. METHODS We retrospectively examined 146 patients and classified them into three groups according to the antithrombotic therapies [dual antiplatelet therapy (DAPT), single antiplatelet therapy (SAPT) plus warfarin, and DAPT plus warfarin] 12 months after stenting. We defined the primary endpoint as Thrombolysis in Myocardial Infarction major bleeding and the secondary endpoint as a composite of adverse events (CAE: all-cause death, nonfatal myocardial infarction, intracranial bleeding, and cerebral infarction). RESULTS During a median follow-up of 37 months, major bleeding and CAE were observed in 14 (9.6%) and 46 (31.5%) patients, respectively. DAPT plus warfarin was an independent risk factor for major bleeding in a multivariate Cox hazard regression model after adjustment for age, gender, and the type of AF (hazard ratio: 4.20; 95% confidence interval: 1.13-17.27; p=0.033). No significant clinical variables were found for CAE. CONCLUSIONS Prolonged use of DAPT with warfarin significantly increases the risk of major bleeding in AF patients after coronary artery stenting. Individualized antithrombotic treatment is required in these patients to prevent major bleeding.

Relationship Between Thrombolytic Therapy and Perfusion Defect Detected by Gd-DTPA–Enhanced Fast Magnetic Resonance Imaging in Acute Myocardial Infarction

To study whether thrombolytic therapy affects Gd-DTPA-enhanced pattern and whether its pattern indicates myocardial viability, Gd-DTPA-enhanced magnetic resonance imaging (MRI) was performed in 43 patients with reperfused acute myocardial infarction 14.8+/-5.0 days after onset with breathhold scanning on a 1.5-T whole body system. The hypoenhanced area at 90 sec after contrast injection was defined as a perfusion defect (PD). Patients were divided into PD(+) and PD(-) groups. The PD was detected in 77.8% of patients treated with direct percutaneous transluminal coronary angioplasty (PTCA) and in 28.6% of patients treated by thrombolytic therapy with or without PTCA in the thrombolysis in myocardial infarction grade 3 group (p < 0.05). The myocardial wall was divided into seven segments based on the American Heart Association committee report. Wall motion of each segment was classified by one of six patterns (wall motion score [WMS]: dyskinesis, -1; akinesis, 0; severe hypokinesis, 1; hypokinesis, 2; slight hypokinesis, 3; normal, 4). By echocardiography, the average WMS and ejection fraction were similar between the PD(+) group and the PD(-) group on admission. Those parameters were significantly worse in the PD(+) group than in PD(-) group 1 month after onset. The change in WMS was significantly lower in the PD(+) group than in the PD(-) group. The number of patients and segments with more than two grades of improvement of WMS in the PD(+) group was significantly lower than that in the PD(-) group. Angiographically, left ventricular ejection fraction and WMS of the PD(+) group were significantly lower than those of the PD(-) group 3 months later. PDs were detected significantly less frequently in patients treated with thrombolytic therapy, suggesting that microvascular embolization related to formation of the no-reflow phenomenon.