Arihiro Hattori

OCT of human carotid arterial plaques.

optical coherence tomography (oct) has not yet been applied to human carotid arteries during carotid artery stenting (CAS). The following images show the value of OCT (M2 OCT Imaging system, LightLab Imaging, Inc., Westford, Massachusetts) used on 20 plaques in 17 patients during CAS under a

Continuous T-wave alternans monitoring to predict impending life-threatening cardiac arrhythmias during emergent coronary reperfusion therapy in patients with acute coronary syndrome

AIMS T-wave alternans (TWA) can precede onset of ventricular tachyarrhythmia (VTA). We evaluated the usefulness of continuous TWA monitoring in ultra-short-term prediction of impending life-threatening VTA upon emergent reperfusion in acute coronary syndrome (ACS) patients. METHODS AND RESULTS Twenty consecutive ACS patients undergoing emergent reperfusion therapy were studied. Continuous ambulatory electrocardiograms (ECGs) (leads V1 and V5) were recorded during emergency room visit and therapy. Peak TWA was determined before and after reperfusion by the modified moving average method. Coronary balloon angioplasty/stenting was successfully performed in 19 patients and intracoronary vasodilator was administered in 1 patient with coronary spasm. Three (15.0%) patients developed VTA requiring cardioversion soon after reperfusion. Peak TWA before reperfusion was higher in patients with VTA than in those without (33.0 ± 4.4 vs. 15.8 ± 4.0 µV, P < 0.001). Two patients with arrhythmia exhibited an upsurge in TWA to 75 and 105 µV before onset of VTA. In the third patient, macroscopic TWA appeared in leads V1-V4 in a 12-lead ECG prior to VTA upon pharmacological resolution of vasospasm, although the ambulatory ECG field of view could not detect the upsurge. CONCLUSION Acute coronary syndrome patients at risk of developing VTA soon after reperfusion exhibit premonitory episodes of increased TWA. Thus, TWA monitoring may be useful for ultra-short-term prediction of life-threatening cardiac arrhythmia risk upon emergent reperfusion in ACS patients. Continuous 12-lead ECGs may be required to optimize detection of TWA, which is regionally specific.

Postconditioning effect of granulocyte colony-stimulating factor is mediated through activation of risk pathway and opening of the mitochondrial KATP channels.

Granulocyte colony-stimulating factor (G-CSF) has been reported to improve cardiac function after myocardial infarction. However, whether postinfarct acute effect of G-CSF is mediated through the same signaling pathways as those of ischemic postconditioning is still unclear. We examined the postinfarct acute effect of G-CSF on myocardial infarct size and its precise molecular mechanism. Japanese white rabbits underwent 30 min of ischemia and 48 h of reperfusion. Rabbits were intravenously injected 10 μg/kg of G-CSF (G-CSF group) or saline (control group) immediately after reperfusion. The wortmannin + G-CSF, PD-98059 + G-CSF, N(ω)-nitro-L-arginine methyl ester (l-NAME) + G-CSF, and 5-hydroxydecanoic acid sodium salt (5-HD) + G-CSF groups were respectively injected with wortmannin (0.6 mg/kg), PD-98059 (0.3 mg/kg), L-NAME (10 mg/kg), and 5-HD (5 mg/kg) 5 min before G-CSF administration. Myocardial infarct size was calculated as a percentage of the risk area of the left ventricle. Western blot analysis was performed to examine the signals such as protein kinase B (Akt), extracellular signal-regulated protein kinase (ERK), eNOS, p70S6 kinase (p70S6K), and glycogen synthase kinase-3β (GSK3β) in the ischemic myocardium after 48 h of reperfusion. The infarct size was significantly smaller in the G-CSF group (26.7 ± 2.7%) than in the control group (42.3 ± 4.6%). The infarct size-reducing effect of G-CSF was completely blocked by wortmannin (44.7 ± 4.8%), PD-98059 (38.3 ± 3.9%), L-NAME (42.1 ± 4.2%), and 5-HD (42.5 ± 1.7%). Wortmannin, PD-98059, L-NAME, or 5-HD alone did not affect the infarct size. Western blotting showed higher myocardial expression of phospho-Akt, phospho-ERK, phosho-eNOS, phosho-p70S6K, and phosho-GSK3β at 10 min and 48 h after reperfusion in the G-CSF group than in the control group. In conclusion, postreperfusion G-CSF administration reduces myocardial infarct size via activation of phosphatidylinositol 3-kinase-Akt and ERK prosurvival signaling pathways and their downstream targets eNOS, p70S6 kinase, GSK3β, and mitochondrial ATP-dependent K(+) channel.

Demonstration of intraluminal thrombus in the carotid artery by optical coherence tomography: technical case report.

OBJECTIVE Intraluminal thrombus in the carotid artery is often misdiagnosed because clinical imaging, such as angiography and duplex ultrasonography, fails to accurately identify it. Recently, it was reported that optical coherence tomography (OCT), a new imaging modality, can visualize intravascular thrombus in the coronary artery. CLINICAL PRESENTATION An 83-year old male was admitted due to newly developed motor weakness of the left hand. Diffusion weighted magnetic resonance imaging showed multiple high intensity spots in the territory of the right middle cerebral artery, and magnetic resonance angiography revealed significant stenosis at the origin of the right internal carotid artery. Because of an apparent change in plaque shape on the angiogram just before carotid artery stenting, further examinations such as intravascular ultrasonography (IVUS) and OCT were performed. EXAMINATION After IVUS examination, both the common carotid and external carotid arteries were occluded by an occlusion balloon system prepared for carotid artery stenting. Then the stenotic site was imaged by OCT from the distal section at 1mm/sec using a built-in pull-back system with continuous injection of saline through the guiding catheter to remove blood from the field of view. Since intraluminal thrombus was clearly demonstrated by an OCT, carotid endarterectomy was performed instead of stenting, and thrombus was confirmed by surgical specimen. CONCLUSION OCT may provide useful information for diagnosis of an intraluminal thrombus in the carotid artery, which is important for the appropriate selection of therapeutic strategy.

Both stimulation of GLP‐1 receptors and inhibition of glycogenolysis additively contribute to a protective effect of oral miglitol against ischaemia‐reperfusion injury in rabbits

BACKGROUND AND PURPOSE We previously reported that pre‐ischaemic i.v. miglitol reduces myocardial infarct size through the inhibition of glycogenolysis during ischaemia. Oral administration of miglitol has been reported to produce glucagon‐like peptide 1 (GLP‐1). We hypothesized that p.o. administration of miglitol, an absorbable antidiabetic drug, reduces myocardial infarct size by stimulating GLP‐1 receptors and inhibiting glycogenolysis in the myocardium.

Elevated plasma GLP-1 levels and enhanced expression of cardiac GLP-1 receptors as markers of left ventricular systolic dysfunction: a cross-sectional study

Objective We aimed to elucidate usefulness of plasma glucagon-like peptide-1 (GLP-1) levels for the assessment of left ventricular (LV) dysfunction by examining the relationship among plasma GLP-1 levels, expression of cardiac GLP-1 receptors and LV function in patients with impaired and preserved LV function. Design Prospective study. Setting Number of participating center: 1, Gifu, Japan. Participants Number of patients enrolled: 102 patients who underwent elective cardiac catheterisation for coronary artery disease, cardiomyopathy and valvular heart disease, and 6 patients who underwent cardiac biopsy. Results The plasma GLP-1 level was significantly increased in patients with impaired LV function (5.7±1.9 pmol/L) as compared with those with preserved LV function (2.7±1.6 pmol/L). Plasma GLP-1 and plasma brain natriuretic peptide (BNP) levels were inversely correlated with the LV ejection fraction(EF), respectively. Plasma GLP-1 level positively correlated with plasma BNP level. Multivariate logistic regression analysis revealed that plasma GLP-1 level was an independent determinant of the impaired LV function, whereas plasma BNP level was not. Intensity of immunostaining for GLP-1 receptor protein was significantly enhanced in patients with impaired LV function compared with those with preserved LV function. Conclusions The plasma GLP-1 level was increased in patients with impaired systolic LV function and inversely correlated with the LVEF. The expressions of GLP-1 receptors were enhanced in hearts with impaired LV function. These may suggest that endogenous GLP-1-GLP-1 receptor system serves as a compensatory mechanism for systolic LV dysfunction. Trial registration UMIN-CTR, ID=UMIN000009361, registration number: R000011000.

Relationship among coronary plaque compliance, coronary risk factors and tissue characteristics evaluated by integrated backscatter intravascular ultrasound

BackgroundThe purpose of the present study was to evaluate the mechanical properties of coronary plaques and plaque behavior, and to elucidate the relationship among tissue characteristics of coronary plaques, mechanical properties and coronary risk factors using integrated backscatter intravascular ultrasound (IB-IVUS).MethodsNon-targeted plaques with moderate stenosis (plaque burden at the minimal lumen site: 50-70%) located proximal to the site of the percutaneous coronary intervention target lesions were evaluated by IB-IVUS. Thirty-six plaques (less calcified group: an arc of calcification ≤10°) in 36 patients and 22 plaques (moderately calcified group: 10° < an arc of calcification ≤60°) in 22 patients were evaluated. External elastic membrane volume (EEMV) compliance, lumen volume (LV) compliance, plaque volume (PV) response (difference between PV in systole and diastole), EEM area stiffness index were measured at the minimal lumen site. Relative lipid volume (lipid volume/internal elastic membrane volume) was calculated by IB-IVUS.ResultsIn the less calcified group, there was a significant correlation between EEMV compliance and the relative lipid volume (r = 0.456, p = 0.005). There was a significant inverse correlation between EEM area stiffness index and the relative lipid volume (p = 0.032, r = −0.358). The LV compliance and EEM area stiffness index were significantly different in the diabetes mellitus (DM) group than in the non-DM group (1.32 ± 1.49 vs. 2.47 ± 1.79%/10 mmHg, p =0.014 and 28.3 ± 26.0 vs. 15.7 ± 17.2, p =0.020). The EEMV compliance and EEM area stiffness index were significantly different in the hypertension (HTN) group than in the non-HTN group (0.77 ± 0.68 vs. 1.57 ± 0.95%/10 mmHg, p =0.012 and 26.5 ± 24.3 vs. 13.0 ± 16.7, p =0.020). These relationships were not seen in the moderately calcified group.ConclusionThe present study provided new findings that there was a significant correlation between mechanical properties and tissue characteristics of coronary arteries. In addition, our results suggested that the EEMV compliance and the LV compliance were independent and the compliance was significantly impaired in the patients with DM and/or HTN. Assessment of coronary mechanical properties during PCI may provide us with useful information regarding the risk stratification of patients with coronary heart disease.

In-hospital monitoring of T-wave alternans in a case of amiodarone-induced torsade de pointes: clinical and methodologic insights

We report a case of macroscopic T-wave alternans occurring 30 min before the onset of amiodarone-induced torsade de pointes, illustrating a means to monitor for proarrhythmia.

Comparison between integrated backscatter intravascular ultrasound and 64-slice multi-detector row computed tomography for tissue characterization and volumetric assessment of coronary plaques.

BackgroundThe purpose of this study was to determine the cut-off values of Hounsfield units (HU) for the discrimination of plaque components and to evaluate the feasibility of measurement of the volume of plaque components using multi-detector row computed tomography (MDCT).MethodsCoronary lesions (125 lesions in 125 patients) were visualized by both integrated backscatter intravascular ultrasound (IB-IVUS) and 64-slice MDCT at the same site. The IB values were used as a gold standard to determine the cut off values of HU for the discrimination of plaque components.ResultsPlaques were classified as lipid pool (n =50), fibrosis (n =65) or calcification (n =35) by IB-IVUS. The HU of lipid pool, fibrosis and calcification were 18 ± 18 HU (−19 to 58 HU), 95 ± 24 HU (46 to 154 HU) and 378 ± 99 HU (188 to 605 HU), respectively. Using receiver operating characteristic curve analysis, a threshold of 50 HU was the optimal cutoff values to discriminate lipid pool from fibrosis. Lipid volume measured by MDCT was correlated with that measured by IB-IVUS (r =0.66, p <0.001), whereas fibrous volume was not (r =0.21, p =0.059).ConclusionLipid volume measured by MDCT was moderately correlated with that measured by IB-IVUS. MDCT may be useful for volumetric assessment of the lipid volume of coronary plaques, whereas the assessment of fibrosis volume was unstable.

Treatment with Lindera strychnifolia Reduces Blood Pressure by Decreasing Sympathetic Nerve Activity in Spontaneously Hypertensive Rats

Lindera strychnifolia (Tendai-Uyaku), a medicinal plant, has long been used for the treatment of cardiac, renal and rheumatic diseases in Japan. We investigated the effect of Lindera strychnifolia on systolic blood pressure, cardiac function, and plasma noradrenaline levels in rats. Spontaneously hypertensive rats (SHR) were given free access to water or extract solution of Lindera strychnifolia, which was extracted with a ratio of 10 g Lindera strychnifolia roots/20 ml water. Systolic blood pressure was measured by using a tail-cuf sphygmomanometer twice a week from 10 to 30 weeks of age, and compared to the age-matched Wistar Kyoto rats (WKY) as a control group. At 30 weeks of age, heart function was measured by echocardiography and blood samples were taken for detection of plasma noradrenaline levels, and rats were then sacrificed. Systolic blood pressure gradually increased from 10 to 30 weeks of age in the SHR group, while it did not change in the WKY group. In the Lindera-treated SHR group, the increase in systolic blood pressure was significantly attenuated from 21 to 30 weeks of age. Echocardiography showed a significant increase in ejection fraction in the Lindera-treated SHR group (60.4 +/- 7.8%) as compared to the SHR group (39.7 +/- 23.4%). Plasma noradrenaline levels were significantly decreased in Lindera-treated SHR group compared to the SHR group. These results suggest that Lindera strychnifolia has an anti-hypertensive effect and improves cardiac function in spontaneous hypertensive rats. These effects may be related to the decrease in plasma noradrenaline levels by Lindera strychnifolia.