Publications by authors named "Ami Shimamura"

A 9-year-old boy was suspected of having acute myocardial infarction and emergency coronary angiogram was performed. No signs of flow limitation in either coronary artery was detected. We performed intravascular ultrasonography from the ascending aorta, which showed a ridge on the left main trunk acting like a valve, resulting in significant stenosis.

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Background: Validation and standardization of methodologies for microbial community measurements by high-throughput sequencing are needed to support human microbiome research and its industrialization. This study set out to establish standards-based solutions to improve the accuracy and reproducibility of metagenomics-based microbiome profiling of human fecal samples.

Results: In the first phase, we performed a head-to-head comparison of a wide range of protocols for DNA extraction and sequencing library construction using defined mock communities, to identify performant protocols and pinpoint sources of inaccuracy in quantification.

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Objectives: This study sought to investigate the ability of combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS) to differentiate plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN) in acute myocardial infarction (AMI).

Background: Most acute coronary syndromes occur from coronary thrombosis based on PR, PE, or CN. In vivo differentiation among PR, PE, and CN is a major challenge for intravascular imaging.

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Background: There are limited data available regarding the use of diastolic deceleration time (DDT) of three major arteries measured by transthoracic echocardiography (TTE) for assessing coronary microvascular damage after acute myocardial infarction (AMI). Therefore, we aimed to compare the DDT of three major arteries using TTE with the transmural extent of infarction (TEI) and infarct size, which were classified using contrast-enhanced magnetic resonance imaging (CE-MRI), in patients with AMI.

Methods: The DDT of the culprit coronary artery was measured in 74 patients using TTE and CE-MRI 1 week after the onset of AMI.

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Background: It has been widely documented that circannual variation has an impact on the incidence and prognosis of cardiovascular diseases. It is unclear why cold ambient temperature increase the incidence of acute myocardial infarction (AMI). We investigated the relationship between the ambient temperature at the onset of AMI, the morphology of the culprit lesion in patients with AMI.

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Background: Acute myocardial infarction (AMI) is caused by coronary plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN). We used optical coherence tomography (OCT) to compare stent expansion immediately after primary percutaneous coronary intervention (PCI) in patients with AMI caused by PR, PE, or CN.

Methods and results: In all, 288 AMI patients were assessed by OCT before and immediately after PCI, performed with OCT guidance according to OPINION criteria for stent sizing and optimization.

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Background: We aimed to determine the predictive value of longitudinal, circumferential, and radial strains by two-dimensional speckle tracking echocardiography (2DSTE) for improvement in cardiac function after acute myocardial infarction (AMI) compared with that of contrast-enhanced cardiac magnetic resonance imaging (ceMRI).

Methods: In 35 patients with first-time AMI, myocardial viability was assessed to predict recovery of function at follow-up (7 ± 2 months), prospectively. For each left ventricular segment, each peak strains were determined using 2DSTE, and the relative extent of hyperenhancement was assessed using ceMRI.

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T2 weighted (T2W) images on cardiovascular magnetic resonance (CMR) visualizes myocardial edema, which reflects the myocardial area at risk (AAR) in reperfused acute myocardial infarction (AMI). Late gadolinium enhancement (LGE) demonstrates myocardial infarction. LGE images cover the whole left ventricle, but T2W images are obtained from a few slices of the left ventricle due to the long sequence time, so the quantification of AAR of the entire left ventricle is difficult.

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Objective: Although monocytes appear to be actively involved in the onset of acute coronary syndrome (ACS), they are heterogenous in human peripheral blood. How up-regulation of monocyte subsets leads to coronary plaque rupture followed by thrombus formation remains unclear. Recent studies have shown that P-selectin glycoprotein ligand-1 (PSGL-1) is involved in monocyte activation in patients with thrombus formation.

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Some patients with acute myocardial infarction (AMI) have a poor prognosis due to left ventricular remodeling (LVR), resulting in the recurrence of congestive heart failure even when therapy with angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) has been initiated. We investigated the effect of early administration of the direct renin inhibitor (DRI) aliskiren in combination with an ACEI or an ARB on LVR using cardiac magnetic resonance (CMR) imaging in patients with AMI.Twenty-one consecutive patients were treated with an ACEI or an ARB (non-DRI group), and another 21 consecutive patients received aliskiren 150 mg/day combined with an ACEI or an ARB (DRI group).

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Background And Aims: It remains unclear whether glycemic fluctuation can affect plaque rupture in acute myocardial infarction (AMI). Here we investigate the impact of glucose fluctuation on plaque rupture, as observed by optical coherence tomography (OCT), and monocyte subsets in patients with AMI.

Methods And Results: We studied 37 consecutive patients with AMI.

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Background: It remains unclear whether glycemic fluctuation immediately after acute myocardial infarction (AMI) can affect myocardial damage. This study investigated the impact of glucose fluctuation on myocardial salvage following successful recanalization of primary AMI.

Methods And Results: A total of 36 consecutive patients with AMI were studied.

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Objectives: This study sought to investigate the relationship between the degree of microvascular dysfunction assessed by a dual-sensor guidewire (pressure and Doppler velocity) and left ventricular (LV) remodeling after successful primary percutaneous coronary intervention (PPCI) for a first anterior acute myocardial infarction (AMI).

Background: Microvascular dysfunction after AMI is associated with progressive LV dilation.

Methods: In 24 consecutive patients, the microvascular resistance index (MVRI) immediately after PPCI was calculated as the ratio of the mean distal pressure to average peak flow velocity during maximal hyperemia.

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Objectives: The aim of the study was to investigate whether intravascular ultrasound (IVUS) can predict microvascular obstruction (MVO) as detected by magnetic resonance imaging (MRI) after primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI).

Background: MVO occurs in a sizable proportion of patients with acute myocardial infarction despite successful PCI and results in poor clinical outcomes.

Methods: We assessed infarct-related lesions in 68 patients with STEMI by using IVUS before primary PCI.

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Background: It remains unclear whether angiotensin-converting enzyme inhibitors (ACEIs) or angiotensin II type 1 receptor blockers (ARBs) have fully delivered the expected reduction in cardiovascular diseases. We investigated the effects of adding the direct renin inhibitor (DRI), aliskiren, to an ACEI or an ARB on monocyte subsets and myocardial salvage in patients with primary acute myocardial infarction (AMI).

Methods And Results: Twenty-one consecutive patients were treated with an ACEI or an ARB (non-DRI group), and another 21 consecutive patients received aliskiren combined with an ACEI or an ARB (DRI group).

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Coronary malperfusion due to acute aortic dissection (AAD) is a relatively rare, but fatal condition. We experienced a case of acute myocardial infarction (AMI) with cardiogenic shock due to compression of the left main trunk (LMT) by a false lumen of an AAD. Percutaneous coronary intervention (PCI) to the LMT was firstly performed, followed by a definitive surgery under a stable hemodynamic condition.

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Lymphomatoid granulomatosis (LG) is an angiocentric and angiodestructive lymphoproliferative disease that mainly involves the lung. Thirty percent of patients with LG have neurological symptoms. We report serial changes in MRI of a patient with LG of the brain.

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From January 2001 to January 2003, we performed 25 emergency off-pump coronary artery bypass grafting (CABG) procedures for patients with acute myocardial infarction (AMI) or unstable angina pectoris. During the same period, we also performed 2 emergency on-pump beating CABG procedures for patients with left main coronary trunk (LMT) shock syndrome. For the present study, we evaluated the operative results of the 25 cases of emergency or urgent off-pump CABG.

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A 67-year-old man temporarily complained of hearing loss and earache in the left side. Afterwards, hearing impairment in the right, pharyngalgia, dysphagia, and ipsilateral facial weakness occurred, however, otological treatments did not completely improve these symptoms except facial weakness. On admission neurological examination revealed right cranial nerve palsies(IX, X, XII), and severe orthostatic hypotension was noted one month after admission.

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We have treated 10 patients of left ventricular free wall rupture (LVFWR) resulting from acute myocardial infarction (AMI) in our intensive care unit (ICU) from Oct. 1984 to Dec. 1993.

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