Haruyuki Taguchi

Napkin-Ring Sign on Coronary CT Angiography for the Prediction of Acute Coronary Syndrome

OBJECTIVES The aim of this study was to determine the predictive value of the napkin-ring sign on coronary computed tomography angiography (CTA) for future acute coronary syndrome (ACS) events in patients with coronary artery disease. BACKGROUND Recent studies have reported a close association between the napkin-ring sign on coronary CTA and thin-cap fibroatheroma. METHODS The subjects of this prospective study were 895 consecutive patients who underwent coronary CTA examination and were followed for >1 year. The primary endpoint was an ACS event (cardiac death, nonfatal myocardial infarction, or unstable angina pectoris). The coronary CTA analysis included the presence of obstructive plaque, positive remodeling (PR), low-attenuation plaque (LAP), and the napkin-ring sign. The napkin-ring sign was defined by the following criteria: 1) the presence of a ring of high attenuation around certain coronary artery plaques; and 2) attenuation of the ring presenting higher than those of the adjacent plaque and no >130 Hounsfield units. RESULTS Of the 12,727 segments, 1,174 plaques were observed, including plaques with PR in 130 segments (1.0%), LAP in 107 segments (0.8%), and napkin-ring signs in 45 segments (0.4%). Thirty-six of the 45 plaques with napkin-ring signs (80%) overlapped with those showing either PR or LAP. During the follow-up period (2.3 ± 0.8 years), 24 patients (2.6%) experienced ACS events, and plaques developed in 41% with a napkin-ring sign. Segment-based Cox proportional hazards models analysis showed that PR (p < 0.001), LAP (p = 0.007), and the napkin-ring sign (p < 0.0001) were independent predictive factors for future ACS events. Kaplan-Meier analysis demonstrated that plaques with napkin-ring signs showed a higher risk of ACS events compared with those without a napkin-ring sign. CONCLUSIONS The present study demonstrated for the first time that the napkin-ring sign demonstrated on coronary CTA was strongly associated with future ACS events, independent of other high-risk coronary CTA features. Detection of the napkin-ring sign could help identify coronary artery disease patients at high risk of future ACS events.

Tissue Doppler-derived index of left ventricular filling pressure, E/E′, predicts survival of patients with non-valvular atrial fibrillation

Objectives: To investigate whether the ratio of early transmitral flow velocity (E) to early diastolic mitral annular velocity (E′) predict prognosis in patients with non-valvular atrial fibrillation. Methods: 230 patients with non-valvular atrial fibrillation were enrolled and studied. According to E/E′ value, patients were divided into groups with lower (group A with E/E′ ⩽ 15) and higher (group B with E/E′ > 15) E/E′. Results: During follow up (average 245 days), 21 (9.1%) deaths were documented. All cause death (15/90 (16.7%) v 6/140 (4.3%)), cardiac death (10 (11.1%) v 2 (1.4%)) and congestive heart failure (16 (17.8%) v 8 (5.7%)) were more common in group B than in group A (all p < 0.01). A Kaplan–Meier survival curve showed that the cumulative survival rate was significantly lower in group B than in group A (log rank p  =  0.0013). By multivariate logistic regression analysis, E/E′ (χ2  =  4.47, odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.11, p  =  0.03) and age (χ2  =  6.45, OR 1.06, 95% CI 1.01 to 1.11, p  =  0.02) were independent predictors of mortality. Conclusion: The Doppler-derived index of left ventricular filling pressure, E/E′, is a powerful predictor of the clinical outcome of patients with non-valvular atrial fibrillation.

Prevalence of spontaneous coronary artery dissection in patients with acute coronary syndrome

Aims: Spontaneous coronary artery dissection (SCAD) found typically in young females without classical coronary risk factors is thought to be a very rare cause of acute coronary syndrome (ACS). The prevalence of SCAD in ACS subjects has been unclear, probably due to the nature of coronary angiography. The aim of this study was to use optical coherence tomography (OCT) to investigate the prevalence of SCAD in ACS. Methods and results: This study consisted of 326 patients with ACS (with or without ST-segment elevation) who underwent OCT to explore the entire culprit artery. According to OCT findings, patients were divided into a SCAD, a plaque rupture (PR), and a non-SCAD/non-PR group. OCT revealed 13 (4.0%) SCADs and 160 (49.1%) plaque ruptures in ACS subjects. The percentage of females versus males was greater in the SCAD group (SCAD: 53.8% vs. PR: 20.0% vs. non-SCAD/non-PR: 23.5%, p=0.02) while no difference was observed in age (SCAD: 67.3±13.3 vs. PR: 66.5±11.1 vs. non-SCAD/non-PR: 67.0±10.5, p=0.90). The prevalence of dyslipidemia (SCAD: 30.8% vs. PR: 63.8% vs. non-SCAD/non-PR: 67.5%, p=0.03) and current smoking (SCAD: 7.7% vs. PR: 57.9% vs. non-SCAD/non-PR: 59.7%, p<0.01) were significantly lower in the SCAD group. Conclusions: SCAD is not a rare cause for ACS, especially in females without classical coronary risk factors.

A Prospective, Multicenter, Randomized Trial to Assess Efficacy of Pioglitazone on In-Stent Neointimal Suppression in Type 2 Diabetes : POPPS (Prevention of In-Stent Neointimal Proliferation by Pioglitazone Study)

OBJECTIVES The aim of this study was to clarify whether pioglitazone suppresses in-stent neointimal proliferation and reduces restenosis and target lesion revascularization (TLR) after percutaneous coronary intervention (PCI). BACKGROUND Previous single-center studies have demonstrated the anti-restenotic effect of a peroxisome proliferator-activated receptor gamma agonist, pioglitazone, after PCI. METHODS A total of 97 patients with type 2 diabetes mellitus (T2DM) undergoing PCI (bare-metal stents only) were enrolled. After PCI, patients were randomly assigned to either the pioglitazone group (n = 48) or the control group (n = 49). Angiographical and intravascular ultrasound (IVUS) imaging were performed at baseline and repeated at 6-month follow-up. Primary end points included angiographical restenosis and TLR at 6 months follow-up. Secondary end point was in-stent neointimal volume by IVUS. RESULTS Baseline glucose level and glycosylated hemoglobin (HbA1c) level were similar between the pioglitazone group and the control group. Angiographical restenosis rate was 17% in the pioglitazone group and 35% in control group (p = 0.06). The TLR was significantly lower in pioglitazone group than in control group (12.5% vs. 29.8%, p = 0.04). By IVUS (n = 56), in-stent neointimal volume at 6 months showed a trend toward smaller in the pioglitazone group than in the control group (48.0 +/- 30.2 mm(3) vs. 62.7 +/- 29.0 mm(3), p = 0.07). Neointimal index (neointimal volume/stent volume x 100) was significantly smaller in the pioglitazone group than in the control group (31.1 +/- 14.3% vs. 40.5 +/- 12.9%, p = 0.01). CONCLUSIONS Pioglitazone treatment might suppress in-stent neointimal proliferation and reduce incidence of TLR after PCI in patients with T2DM.

Lesion characteristics of acute myocardial infarction: an investigation with intravascular ultrasound

OBJECTIVE To use intravascular ultrasound (IVUS) to compare plaque morphology in acute myocardial infarction and stable angina pectoris. DESIGN Retrospective study. SETTING Primary care hospital. PATIENTS 59 consecutive cases of acute myocardial infarction and 50 consecutive cases of stable angina pectoris. METHODS IVUS was used before coronary intervention. MAIN OUTCOME MEASURES Plaque morphology (incidence of eccentric plaque, subtle dissections, low echoic thrombus, calcification, echolucent areas, and bright speckled echo material), assessed visually using IVUS. RESULTS There were no significant differences in plaque eccentricity or calcification between the two groups, but low echoic thrombus (acute myocardial infarction 15%v stable angina pectoris 0%), subtle dissections (37% v 4%), echolucent areas (31% v 0%), and bright speckled echo material (90% v 0%) were more common in the infarction group than in the stable angina group (p < 0.001 for all). There was a longer time between the onset of symptoms and the IVUS examination in patients with low echoic thrombus than in those without (p < 0.03). CONCLUSIONS Low echoic thrombus, subtle dissections, echolucent areas, and bright speckled echo material are morphological characteristics associated with plaque at the time of acute myocardial infarction. These findings correspond pathologically to ruptured plaque.

Conformational change in coronary artery structure assessed by optical coherence tomography in patients with vasospastic angina.

OBJECTIVES The aim of this study was to investigate the conformational change of arterial structure in the vasospastic lesion with optical coherence tomography. BACKGROUND Coronary artery spasm plays an important role in the pathogenesis of ischemic heart diseases. The conformational change of each arterial layer during vasospasm has not been studied in detail. METHODS We assessed 19 coronary arteries (10 spasm and 9 nonspasm lesions) with optical coherence tomography during the provocation test for coronary spasm. An intimal bump was defined as 1 or more intimal projections into the lumen that disappeared after the administration of nitroglycerine (NTG). Intimal gathering was defined as a folding/gathering of the intima, resulting in multiple kinks in the luminal contour that resolved after the administration of NTG. RESULTS The spasm lesion more frequently showed an intimal bump at baseline and intimal gathering during spasm compared with the nonspasm lesion (spasm 80% vs. nonspasm 0%, p < 0.01, spasm 100% vs. nonspasm 0%, p < 0.01, respectively). The spasm lesion demonstrated a thicker maximum media thickness (spasm 0.24 ± 0.04 mm vs. nonspasm 0.12 ± 0.03 mm, p < 0.01) at baseline, whereas no differences were observed after the administration of NTG (spasm 0.13 ± 0.03 mm vs. nonspasm 0.13 ± 0.02 mm, p = 0.65). CONCLUSIONS Our results suggest that medial contraction occurs even in an asymptomatic state and facilitates the formation of an intimal bump in patients with vasospastic angina. Luminal narrowing during spasm is associated with intimal gathering without alteration of intimal area.

Direct Measurement of Wall Stiffness for Carotid Arteries by Ultrasound Strain Imaging

OBJECTIVE The elastic properties of the carotid arterial wall have not been directly characterized in the clinical setting. Strain rate (SR) imaging is a newly developed echocardiographic method developed for imaging the tissue motion of the myocardium. The purpose of this study was to directly estimate the elastic properties of the carotid artery by using SR imaging in patients with coronary artery disease (CAD). METHODS A total of 135 patients with CAD, 15 age-matched controls, and 35 young healthy subjects had a carotid ultrasound examination for measuring the values of SR and strain of the carotid artery. The intima-media thickness and distensibility coefficient of the carotid artery were estimated. RESULTS Age and Framingham risk score were significantly related to SR and strain, respectively (r = 0.62-0.67, all P < .001). These strain measurements were significantly correlated with distensibility coefficient and intima-media thickness, respectively (r = 0.30-0.56, all P < .001). Similar values of the areas under the receiver operating characteristic curves were obtained among Framingham risk score (0.70 +/- 0.05), SR (0.67 +/- 0.05), and strain (0.73 +/- 0.05). CONCLUSION This study demonstrated that the elastic properties of the carotid artery wall were directly characterized by using SR imaging in patients with CAD.

Effect of Culprit-Lesion Remodeling Versus Plaque Rupture on Three-Year Outcome in Patients With Acute Coronary Syndrome

To investigate intravascular ultrasound predictors of long-term clinical outcome in patients with acute coronary syndrome, 94 patients with a first acute coronary syndrome with both preintervention intravascular ultrasound imaging and long-term follow-up were enrolled in this study. Remodeling index was defined as external elastic membrane cross-sectional area at the target lesion divided by that at the proximal reference. Arterial remodeling was defined as either positive (PR: remodeling index >1.05) or intermediate/negative remodeling (remodeling index < or =1.05). Clinical events were death, myocardial infarction, and target-lesion revascularization. Patients were followed up for a mean of 3 years. PR was observed in 50 (53%), and intermediate/negative remodeling, in 44 (47%). During the 3-year follow-up, there were 20 target-lesion revascularization events and 5 deaths (2 cardiac and 3 noncardiac), but no myocardial infarctions. Patients with PR showed significantly lower major adverse cardiac event (MACE; death, myocardial infarction, and target-lesion revascularization)-free survival (log-rank p = 0.03). However, patients with plaque rupture showed a nonsignificant trend toward lower MACE-free survival (p = 0.13), but there were no significant differences in MACE-free survival between those with single versus multiple plaque ruptures. Using multivariate logistic regression analysis, only culprit lesion PR was an independent predictor of MACEs (p = 0.04). In conclusion, culprit-lesion remodeling rather than the presence or absence of culprit-lesion plaque rupture was a strong predictor of long-term (3-year) clinical outcome in patients with acute coronary syndrome.

Remote ischemic conditioning improves coronary microcirculation in healthy subjects and patients with heart failure

Background Remote ischemic conditioning (RIC) is a treatment modality that suppresses inflammation and improves endothelial function, which are factors involved in the pathogenesis of heart failure (HF) with reduced left ventricular ejection fraction. Coronary flow reserve (CFR) is a physiological index of coronary microcirculation and is noninvasively measured by transthoracic Doppler echocardiography (TTDE). This study aimed to investigate the effects of RIC on CFR in healthy subjects and patients with HF, through the assessment by TTDE. Methods Ten patients with HF with left ventricular ejection fraction of less than 40%, and ten healthy volunteers were enrolled in this study. RIC treatment was performed twice a day for 1 week. Our custom-made RIC device was programmed to automatically conduct 4 cycles of 5 minutes inflation and 5 minutes deflation of a blood pressure cuff to create intermittent arm ischemia. CFR measurements and laboratory tests were examined before, and after 1 week of RIC treatment. Results One week of RIC treatment was well tolerated in both groups. RIC treatment increased CFR from 4.0±0.9 to 4.6±1.3 (mean ± standard deviation) in healthy subjects (P=0.02), and from 1.9±0.4 to 2.3±0.7 in patients with HF (P=0.03), respectively. Systolic blood pressure in healthy subjects, and heart rate in HF patients decreased after RIC treatment (both P<0.01). Conclusion This study demonstrated that a 1 week course of RIC treatment improved coronary microcirculation in healthy subjects and patients with HF associated with reduced left ventricular ejection fraction.

Left atrial thrombus and prognosis after anticoagulation therapy in patients with atrial fibrillation

BACKGROUND Anticoagulation therapy reduces the risk of thromboembolic events by two-thirds in patients with atrial fibrillation (AF). The prevalence of left atrial thrombus (LAT) in AF patients with anticoagulation therapy has not been fully investigated. PURPOSE To investigate the prevalence of LAT and its impact on the outcomes in patients with nonvalvular AF after anticoagulation therapy. METHODS This study consisted of 231 patients with nonvalvular AF who had transthoracic (TTE) and transesophageal echocardiographic (TEE) examinations more than 3 weeks after anticoagulation therapy. The clinical and echocardiographic characteristics were evaluated. RESULTS LAT was observed in 13 (8.8%) of 148 patients with sub-therapeutic anticoagulation, and in 3 (3.6%) of 83 patients with sufficient anticoagulation. The presence of LAT was associated with higher CHADS(2) score, decreased LA volume changes and the presence of spontaneous echocardiographic contrast (SEC) in patients with sub-therapeutic anticoagulation. Patients with LAT after sufficient anticoagulation were male with permanent AF who had decreased left ventricular systolic and diastolic function and dilated LA on TTE and SEC, and reduced appendage flow velocity on TEE. Patients with LAT had worse cardiovascular outcomes compared with those without LAT (p=0.02). CONCLUSIONS We demonstrated that LAT was a univariate risk factor associated with worse cardiovascular outcomes, which was observed in 8.8% of patients with sub-therapeutic anticoagulation and 3.6% of patients with sufficient anticoagulation.