Biomedical subjects

Minoru Yoshiyama

Publications and source records attributed to Minoru Yoshiyama.

At least 19 recordsLinked to original sources

PubMed2006

Xenotransplantation of long-term-cultured swine bone marrow-derived mesenchymal stem cells.

Swine-derived MSCs were efficiently isolated and extensively expanded using a low fetal serum content growth medium to which selected growth factors were added. After > or =96 cell population doublings (PDs), MSCs were devoid of cytogenetic abnormalities. In vitro chondrogenic and osteogenic differentiation capacity was preserved after 80 PDs. To test therapeutic efficacy, 1 x 10(6) 80-PD MSCs were injected directly into the peri-infarct zone of hearts of immunodeficient (non-obese diabetic/severe combined immunodeficient) mice at the time of acute myocardial infarction. Engrafted MSCs survived in the infarcted hearts for at least 4 weeks. Echocardiography at 2 and 4 weeks postinfarction revealed a significant preservation of the left ventricular ejection fractions of infarct hearts receiving MSCs compared with infarct hearts receiving saline. Peri-infarct zone capillarity was better preserved in MSC-treated hearts than other infarct groups of hearts, but infarct size was comparable in all groups. Only rare engrafted MSCs expressed cardiac-specific or endothelial cell-specific markers. Hence, 80-PD MSCs retained the capacity to promote functional improvement in the infarcted heart despite minimal differentiation of MSCs into cardiomyocytes or endothelial cells. These data suggest that the beneficial effects of MSC transplantation most likely result from the trophic effects of MSC-released substances on native cardiac and vascular cells. The capacity to massively expand MSC lines without loss of therapeutic efficacy may prove to be useful in the clinical setting where "off the shelf" MSCs may be required for interventions in patients with acute coronary syndromes.

Adenoviridae↗

PubMed2006

Usefulness of automated quantitation of regional left ventricular wall motion by a novel method of two-dimensional echocardiographic tracking.

A novel 2-dimensional (2-D) echocardiographic tracking method enables the automated tracking of displacement between 2 points of interest in echocardiographic images. The purpose of this study was to evaluate whether this 2-D tracking method could be used to measure left ventricular (LV) wall thickness and percent systolic wall thickening (%WT) in parasternal short-axis views, in comparison with conventional manual measurement, and to determine whether this system can be used to quantitatively assess regional LV wall motion in echocardiography. In 24 subjects (12 with LV wall motion abnormalities), 6 segments in the short-axis images were assessed by this method. Two sample points at the endocardium and epicardium were tracked automatically during 1 cardiac cycle. Then, LV wall thickness and %WT were calculated. In 50 subjects (32 with LV wall motion abnormalities), average %WT as an average of all %WT in every degree of angle in each of the 6 segments was measured by this method, and the results were compared with the visual assessment of LV wall motion scores. There was excellent agreement between the 2-D tracking and manual methods for LV wall thickness (r = 0.99) and %WT (r = 0.97). The mean differences in LV wall thickness and %WT were 0.1 +/- 0.4 mm and 0 +/- 5.4%, respectively. Average %WT was significantly decreased in the regions of hypokinetic or akinetic wall motion compared with those of normal motion (18 +/- 4% and 4 +/- 4% vs 39 +/- 10%, p <0.001). In conclusion, this 2-D tracking method can be used for the noninvasive, automated quantitation of LV wall motion in 2-D echocardiography.

Echocardiography↗

PubMed2006

The effects of HMG-CoA reductase inhibitor on vascular progenitor cells.

Circulating bone marrow-derived vascular progenitor cells contribute to angiogenesis, atherosclerosis, and the response to vascular injury. These vascular progenitor cells consist of two cell groups, endothelial progenitor cells (EPCs) and smooth muscle progenitor cells (SMPCs). Although HMG-CoA reductase inhibitors (statins) have been reported to inhibit atherosclerosis partially by increased EPCs, the effects of statins on SMPCs are unclear. Therefore, we investigated the relationship between EPCs and SMPCs and whether pravastatin has atheroprotective effects on SMPCs. Peripheral mononuclear cells (MNCs) were isolated and cultured on fibronectin-coated dishes in SMPC medium. MNCs were stained with acetylated low density lipoprotein and lectin, or alpha-smooth muscle actin, and cell numbers were counted. mRNA expression and vascular endothelial growth factor (VEGF) protein synthesis of MNCs were evaluated. Pravastatin significantly increased the number of EPC and decreased the number of SMPC. mRNA expression of VEGF, endothelial nitric oxide synthase, VEGF receptor-2 (KDR), and Akt were up-regulated, and VEGF secretion was increased by pravastatin. The present study demonstrated that pravastatin has promotive effects on the differentiation from MNCs to EPC cells, while inhibitory effects to SMPC cells. Our findings suggest a previously unreported mechanism of the effect of statin therapy on vascular progenitor cells.

Actins↗

PubMed2006

Cut-off value of coronary flow velocity reserve by transthoracic Doppler echocardiography for the assessment of significant donor left anterior descending artery stenosis in patients with spontaneously visible collaterals.

We evaluated the influence of collateral circulation on a donor left anterior descending artery and an appropriate cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis. Measurement of coronary flow velocity reserve by transthoracic Doppler echocardiography provides noninvasive assessment of significant left anterior descending artery stenosis. The cut-off value of coronary flow velocity reserve for the diagnosis of significant donor left anterior descending artery stenosis has not been well studied. We retrospectively examined 64 patients who had no significant left anterior descending artery stenosis and who had other coronary artery stenosis. Seventeen patients had collaterals from the left anterior descending artery (group A) and 47 patients did not have collaterals (group B). We prospectively examined 23 consecutive patients who had collaterals from the left anterior descending artery to other coronary arteries. Eight patients had a significant donor left anterior descending artery stenosis. Coronary flow velocity reserve assessment was performed by transthoracic Doppler echocardiography in the 2 protocols. Coronary flow velocity at baseline in group A was significantly higher than that in group B. Coronary flow velocity reserve in group A was significantly lower than that in group B (2.6 +/- 0.8 vs 3.2 +/- 0.9, p < 0.05). Coronary flow velocity during hyperemia and coronary flow velocity reserve were significantly lower in patients with significant stenosis. A cut-off value of 2.0 of coronary flow velocity reserve had a sensitivity of 88% and a specificity of 93% for the diagnosis of significant donor left anterior descending artery stenosis. In conclusion, coronary flow velocity reserve of a donor left anterior descending artery was decreased by the presence of collaterals. However, a cut-off value < 2.0 was appropriate for the diagnosis of significant donor left anterior descending artery stenosis in a population that included patients with collaterals.

Blood Flow Velocity↗

PubMed2006

Persistent high levels of plasma oxidized low-density lipoprotein after acute myocardial infarction predict stent restenosis.

OBJECTIVE: Recently, elevated levels of plasma oxidized low-density lipoprotein (LDL) have been shown to relate to plaque instability in human atherosclerotic lesions. We investigated prospectively patients admitted with acute myocardial infarction (AMI) who underwent primary coronary stenting to evaluate whether the 6-month outcome could be predicted by measuring plasma oxidized LDL (ox-LDL) levels at the time of hospital discharge. METHODS AND RESULTS: Plasma ox-LDL levels were measured in 102 patients with AMI undergoing primary coronary stenting using a highly sensitive ELISA method. Measurements were taken on admission and at discharge, and the findings related to the clinical outcome. At 6-month follow-up, angiographic stent restenosis occurred in 25 (25%) of the 102 AMI patients. Plasma ox-LDL levels at discharge were significantly (P=0.0074) higher in the restenosis group than those in the no-restenosis group (1.03+/-0.65 versus 0.61+/-0.34 ng/5 microg LDL protein). Multiple regression analysis showed that only plasma ox-LDL levels at discharge were a statistically significant independent predictor for late lumen loss after stenting (beta=0.645; P<0.0001). CONCLUSIONS: This prospective study demonstrates that persistence of an increased level of plasma ox-LDL at discharge is a strong independent predictor of stent restenosis at 6-month follow-up in AMI patients.

Aged↗

PubMed2006

Acute myocardial infarction: clinical characteristics and plaque morphology between expansive remodeling and constrictive remodeling by intravascular ultrasound.

BACKGROUND: According to recent intravascular ultrasound (IVUS) studies, expansive remodeling (ER) at the culprit lesion has been observed in almost 50% of patients with acute coronary syndrome and constrictive remodeling (CR) in 30%. The purpose of this study is to investigate the difference between ER and CR at the culprit lesion in patients with acute myocardial infarction (AMI). METHODS AND RESULTS: Preinterventional IVUS images of 73 patients with AMI were identified. The remodeling index (RI) was defined as the ratio of the external elastic membrane (EEM) areas at the culprit lesion to the EEM areas at the proximal reference site. Expansive remodeling was defined as an RI > 1.05; CR, as an RI < 0.95. In patients with AMI, 40 patients (55%) showed ER on IVUS, whereas CR was observed in 18 patients (25%). Patients with ER were significantly older than those with CR (P < .005). The frequency of the presence of calcifications was higher in patients with ER than in those with CR (P < .0005). In patients with AMI with ER, soft plaque with small calcium was the most frequent (58%). Multivariate analysis revealed that age and the presence of calcifications remained as independent predictors of ER. CONCLUSIONS: These findings suggest that ER relates to old age and calcification, and CR may contribute to early plaque progression than ER in patients with AMI.

Age Factors↗

PubMed2006

Noninvasive diagnosis of restenosis by transthoracic Doppler echocardiography after percutaneous coronary intervention: comparison with exercise Tl-SPECT.

OBJECTIVE: Noninvasive methods that have the ability to accurately detect restenosis have been desired in the selection of patients requiring further angiographic evaluation. The present study sought to evaluate the diagnostic potential of transthoracic Doppler echocardiography (TTDE), a noninvasive method for evaluating coronary flow velocity reserve (CFVR), in detecting restenosis after percutaneous coronary intervention (PCI). METHODS: We studied 107 consecutive patients 6 months after undergoing successful PCI on the left anterior descending coronary artery (LAD) lesions for relief of angina pectoris. The flow velocity in the distal LAD was measured by TTDE both at rest and during intravenous infusion of adenosine triphosphate. CFVR was calculated as the ratio of hyperemic to basal mean diastolic flow velocities. We defined a reversible perfusion defect in exercise Tl-201 single-photon emission computed tomography (SPECT) as restenosis. The CFVR measurements by TTDE were compared with the results of SPECT. RESULTS: Complete TTDE data were acquired for 105 of the 107 study patients. A contrast agent was used to obtain adequate Doppler signals in 29 patients. Of the 105 patients, there were 18 patients with abnormal perfusion (group A) and 87 patients with normal perfusion (group B) in the LAD territories on Tl-201 SPECT. CFVR was greater in group B than in group A (1.7 +/- 0.5 vs. 3.7 +/- 0.8, P < 0.0001, respectively). There were 17 patients with CFVR < 2 and 88 patients with CFVR > or = 2. CFVR < 2 predicted restenosis determined by Tl-201 SPECT, with a sensitivity of 94% and a specificity of 100%. CONCLUSIONS: Noninvasive measurement of CFVR by TTDE accurately reflects the physiological severity of coronary narrowing due to restenosis after PCI. This method has possibility of reducing the number of unnecessary coronary angiographies after PCI.

Angioplasty, Balloon, Coronary↗

PubMed2006

Expression of endothelin-converting enzyme, endothelin-1 and endothelin receptors at the site of percutaneous coronary intervention in humans.

OBJECTIVE: The repair process at the site of injury after percutaneous coronary intervention (PCI) is dominated by neointimal formation composed mainly of smooth muscle cells (SMC). Endothelin-1 (ET-1) is a powerful vasoconstrictor and SMC mitogen. Endothelin-converting enzyme (ECE) is the final key enzyme of endothelin processing. The effects of ET-1 are mediated by binding to endothelin type A (ETA) and endothelin type B (ETB) receptors. The ligand/receptor/ligand-producing system (ET system) could be involved in the pathogenesis of neointimal formation in humans. METHODS: Fifteen post-PCI sites obtained at autopsy and eight atherectomy specimens obtained from restenotic sites were investigated using immunohistochemical single and double staining techniques. Frozen sections were stained with antibodies against ECE, ET-1, ETA and ETB receptors, SMC, macrophages and endothelial cells. RESULTS: At the early stage, less than 3 months after PCI, neointimal SMC were positive for ECE, ET-1, ETA and ETB receptors. The expression of ECE, ET-1, ETA and ETB receptors in these neointimal SMC decreased markedly from 6 months onwards. The ECE, ET-1, ETA and ETB receptor-positive cell areas were significantly (P < 0.005) greater in the first 3 months after PCI compared with 6 months or more after PCI. Atherectomy specimens also showed similar positivity. CONCLUSIONS: These observations strongly suggest that the expression of ECE, ET-1, ETA and ETB receptors is enhanced in neointimal SMC at early stages after PCI injury in human coronary arteries. The increased expression of the ET system may contribute to SMC proliferation/migration and vasoconstriction in human post-PCI coronary lesions.

Aged↗

PubMed2006

Risk stratification in patients with Brugada syndrome: analysis of daily fluctuations in 12-lead electrocardiogram (ECG) and signal-averaged electrocardiogram (SAECG).

INTRODUCTION: Risk stratification between symptomatic and asymptomatic patients with Brugada syndrome is not yet established. We compared daily fluctuations in 12-lead electrocardiogram (ECG) and signal-averaged ECG (SAECG) characteristics between symptomatic and asymptomatic patients with Brugada syndrome to identify new markers for distinguishing between high- and low-risk patients. METHODS AND RESULTS: Thirty-five patients with Brugada syndrome underwent ECG and SAECG simultaneously at least 4 times every 3 months. We evaluated daily fluctuations (differences between maximum and minimum values) in ECG and SAECG characteristics and compared them between symptomatic (N = 11), and asymptomatic (N = 24) patients. On ECG, the daily fluctuations in r-J interval (interval from QRS onset to J point) in leads V1, V2, and V6 were significantly larger in symptomatic than in asymptomatic patients (V1; 20 +/- 6 vs 10 +/- 8 msec, P < 0.01, V2; 22 +/- 8 vs 11 +/- 4 msec, P < 0.01, and V6; 24 +/- 7 vs 14 +/- 7 msec, P < 0.01). On SAECG, daily fluctuations in filtered QRS (f-QRS) duration and LAS40 were significantly larger in symptomatic than in asymptomatic patients (f-QRS; 15 +/- 7 vs 9 +/- 4 msec, P < 0.05, and LAS40; 21 +/- 7 vs 10 +/- 6 msec, P < 0.05). CONCLUSIONS: Instability of depolarization appears to be related to the risk of fatal ventricular arrhythmias in patients with Brugada syndrome. Daily fluctuations in ECG and SAECG characteristics could be useful for distinguishing between high- and low-risk patients with Brugada syndrome.

Brugada Syndrome↗

PubMed2006

Coronary flow velocity reserve measurement in three major coronary arteries using transthoracic Doppler echocardiography.

BACKGROUND: Measurement of the coronary flow velocity reserve (CFVR) by transthoracic Doppler echocardiography (TTDE) has been reported to be useful for the noninvasive assessment of significant coronary artery stenosis or myocardial ischemia. The purpose of this study was to evaluate the value of this method in three major coronary arteries for detecting myocardial ischemia in the clinical setting. METHODS: We studied 89 consecutive patients who were referred to our outpatient clinic because of chest pain. We measured CFVR using TTDE in three major coronary arteries. We defined CFVR<2.0 in at least one vessel as being positive for myocardial ischemia. The accuracy of CFVR measurements for detecting myocardial ischemia was determined in comparison with exercise thallium-201 (Tl-201) single photon emission computed tomography (SPECT) as a reference standard. RESULTS: CFVR in at least one vessel was successfully measured in 87 of 89 patients (98%). The sensitivity and specificity of CFVR<2.0 in at least one coronary vessel, in any of the coronary territories, was 86% and 89%, respectively. In terms of assessing myocardial ischemia in each coronary artery territory, the agreement between CFVR<2.0 and Tl-201 SPECT for the left anterior descending coronary artery, the posterior descending coronary artery, and the left circumflex coronary artery territories was 95%, 81%, and 73%, respectively. CONCLUSION: Noninvasive CFVR measurement by TTDE may be useful for detecting myocardial ischemia, as well as for identifying ischemic territories in the clinical setting.

Adenosine Triphosphate↗

PubMed2006

Role of contrast-enhanced dobutamine stress echocardiography in predicting outcome in patients with known or suspected coronary artery disease.

Although the application of intravenous contrast agents during stress echocardiography has been shown to improve diagnostic accuracy for detecting coronary artery disease, less information exists regarding its prognostic value. The aim of this study was to determine the role of contrast-enhanced dobutamine stress echocardiography (DSE) for predicting future cardiac events in patients with coronary artery disease (CAD). We studied 893 patients (mean age: 66, 581 men) with known or suspected CAD undergoing contrast-enhanced DSE. Positivity was defined as new/worsened wall motion abnormality or fixed abnormality during stress. All patients were followed for 15 +/- 10 months to evaluate hard cardiac events (cardiac death and nonfatal myocardial infarction) and total cardiac events (hard cardiac events, congestive heart failure, unstable angina, and late revascularization). Three patients were lost to follow-up, and 128 patients developed cardiac events, including 21 hard cardiac events. The 3-year event free survival rate was significantly lower in patients with positive DSE results than in those with negative DSE results. Stepwise Cox multivariate analysis revealed that positivity of DSE (P < 0.0001, Hazard ratio (HR): 2.48) and peak wall motion score index (WMSI) >1.5 (P < 0.0001, HR: 2.41) were independent predictors for total cardiac events. Considering hard cardiac events, the independent predictors were peak WMSI > 1.5 (P < 0.0001, HR: 6.65) and age > 70 years (P < 0.005, HR: 3.27). We conclude that contrast-enhanced DSE provides important prognostic information for future cardiac events.

Adult↗

PubMed2006

Automated three-dimensional analysis of mitral annular dynamics in patients with myocardial infarction using automated mitral annular tracking method.

BACKGROUND: A newly developed automated mitral annular tracking method (AMAT) has recently become available and enables us to perform automated analysis of mitral annular dynamics. PURPOSE: To evaluate mitral annular dynamics using AMAT. METHODS: AMAT was performed using a Toshiba Aplio SSA-770 ultrasound system in 15 normal healthy volunteers (group N), 16 patients with anterior MI (group A), and 12 inferior MI (group B). The distance between an annular point at end-diastole and at end-systole (distance D) was automatically measured using AMAT at the basal portion of the anterior, lateral, posterior, inferior, and inferoseptal wall. The angle between the mitral annular plane at end-diastole and the direction of movement of each mitral annular point from end-diastole to end-systole (angle A) was also automatically measured at all five mitral annular points. The coefficients of variation (CV) of both distance D and of angle A were calculated as indices of asynchrony of mitral annular dynamics. RESULTS: CV of distance D in group A (22 +/- 9% (P < 0.01 vs group N)) and group B (22 +/- 10% (P < 0.01 vs group N)) were both significantly larger than in group N (13 +/- 4%). CV of angle A in group A (15 +/- 10% (P < 0.05 vs group N)) and group B (15 +/- 10% (P < 0.05 vs group N)) were also significantly larger than that in group N (8 +/- 3%). CONCLUSION: Automated analysis using AMAT showed that mitral annular dynamics of patients with MI were less symmetrical than in normal healthy volunteers.

Adult↗

PubMed2006

Acute hyperglycemia induced by oral glucose loading suppresses coronary microcirculation on transthoracic Doppler echocardiography in healthy young adults.

OBJECTIVES: We sought to evaluate the effect of acute hyperglycemia on coronary microcirculation by noninvasive measurement of coronary flow velocity reserve (CFVR) using transthoracic Doppler echocardiography (TTDE). RESEARCH DESIGN AND METHODS: Measurements of CFVR using TTDE and levels of plasma glucose and serum insulin and lipids were determined before and 1 hour after loading with oral glucose (75-g glucose) in 10 young healthy males (mean age, 30 +/- 2 years) or an artificial sweetener in five of the 10 subjects without coronary risk factors. RESULTS: In all subjects, the levels of plasma glucose and serum insulin significantly increased after glucose loading compared with baseline (5.1 +/- 0.6 vs 7.6 +/- 1.2 mM/l, 6 +/- 3 vs 49 +/- 13 microU/ml, respectively; P < 0.0001). CFVR was significantly decreased 1 hour after acute oral glucose loading (4.4 +/- 0.7-3.8 +/- 0.7, respectively; P < 0.01). There was no significant change in CFVR after loading with an artificial sweetener (4.4 +/- 0.6-4.4 +/- 0.5 cm/sec). CONCLUSIONS: TTDE revealed that acute hyperglycemia induced by oral glucose loading suppresses CFVR in healthy young male subjects. This result suggests that acute hyperglycemia may have adverse effects on coronary microcirculation.

Acute Disease↗

PubMed2006

Quantitative assessment of left ventricular function during contrast-enhanced dobutamine stress echocardiography predicts future cardiac events in diabetic patients.

BACKGROUND: Non-invasive diagnosis and risk stratification of coronary artery disease are important for the selection and optimization of therapeutic interventions in diabetic patients, which may improve survival. The aim of this study was to determine the incremental value of contrast-enhanced dobutamine stress echocardiography (CE-DSE) for risk stratification. METHODS AND RESULTS: CE-DSE was performed in 326 patients with diabetes mellitus (mean age; 66 +/- 10 years, 223 men). All patients were followed up for a mean of 29 months (1-61 months). Dobutamine was infused in a standard protocol with an intravenous contrast agent. The primary endpoints for hard cardiac events included cardiac death and nonfatal myocardial infarction. The primary endpoints for total cardiac events included hard cardiac events, unstable angina pectoris, congestive heart failure, and late coronary revascularization (> 3 months). Cardiac events occurred in 74 patients. The addition of the CE-DSE results, including abnormal left ventricular end-systolic volume response and left ventricular ejection fraction at peak stress < 50%, to the clinical and rest echocardiography model provided incremental information in predicting total cardiac events (increase in chi-square value for the model from 17 to 24, p < 0.05) and hard cardiac events (increase in chi-square value for the model from 18 to 24, p < 0.05). CONCLUSIONS: Quantitative assessment of left ventricular function during CE-DSE provides incremental prognostic information in predicting cardiac events in diabetic patients.

Adult↗

PubMed2006

Effects of erythropoietin on cardiac remodeling after myocardial infarction.

Erythropoietin (EPO) has been suggested to have a cardioprotective effect against ischemia. The purpose of this study was to examine the effects of EPO on cardiac remodeling after myocardial infarction (MI). MI was induced by ligation of the coronary artery in Wistar rats. The rats with MI were randomly divided into untreated MI and two EPO-treated MI groups. EPO was administered subcutaneously by injection once a day for 4 days after MI at 5000 U/kg or 3 times a week for 4 weeks at 1000 U/kg. Five days after MI, EPO prevented the increase in activated caspase 3, matrix metalloproteinase-2, and transcriptional activation of activator protein-1 in non-infarcted myocardium. Four weeks after MI, left ventricular weight, left ventricular end-diastolic pressure, and left ventricular dimension were increased, and ejection fraction and E wave deceleration time were decreased. EPO significantly attenuated this ventricular remodeling and systolic and diastolic dysfunction. In addition, EPO significantly attenuated the interstitial fibrosis and remodeling-related gene expression in non-infarcted myocardium. Furthermore, EPO significantly enhanced angiogenesis and reduced apoptotic cell death in peri-infarcted myocardium. In conclusion, when administered after MI, EPO prevents cardiac remodeling and improves ventricular function with enhanced angiogenesis and reduced apoptosis.

Animals↗

PubMed2006

Effects of treatment for diabetes mellitus on circulating vascular progenitor cells.

The circulating endothelial progenitor cells (EPCs) have an important role in angiogenesis, and the smooth muscle progenitor cells (SMPCs) participate in atherosclerosis. However, little is known about the effects of treatment of diabetes mellitus (DM) on EPCs and SMPCs. Therefore, we investigated the relations between the number of circulating vasucular progenitor cells before and after the treatment for DM. Ten previously untreated DM patients were enrolled in this study. Blood samples were collected before and after treatment. The peripheral mononuclear cells were purified and cultured to differentiate them into EPCs and SMPCs. After two weeks, the number of EPCs was determined by Dil-labeled acetylated low density lipoprotein and lectin binding. The number of SMPCs was evaluated by immunocytochemical staining of alpha-smooth muscle actin. Before treatment, the number of EPCs and SMPCs was significantly related to hemoglobin A1c and blood sugar. Serial examination revealed that improvement of glycemic control significantly increased the number of both EPCs and SMPCs. DM reduces the number of circulating EPCs and SMPCs according to its severity, and treatment of DM significantly increases the number of EPCs and SMPCs, which may be involved in angiogenesis and atherosclerosis in diabetes.

Actins↗

PubMed2006

Coronary artery calcification revisited.

Calcification is a common finding in human coronary arteries. However, there is conflicting evidence for a link between calcification and plaque instability. Current intravascular ultrasound (IVUS) technology allows a definitive detection of the calcification and measurement of the vessel wall. Using preinterventional IVUS images, we clarified that in patients with acute myocardial infarction, small "spotty" calcifications prevailed, associated with a fibrofatty plaque and positive remodeling. Conversely, in patients with stable angina pectoris, extensive calcification was frequent. IVUS allows the detection of vulnerable plaques in coronary arteries, by identifying not only a large lipid core and positive remodeling, but also a spotty pattern of calcification.

Calcinosis↗

PubMed2006

Method analysis for optimal continuous imaging using intravascular optical coherence tomography.

OBJECTIVES: Optical coherence tomography(OCT)is a high-resolution imaging method that can clearly visualize vessels through the displacement of blood with flushing agents. Continuous imaging methods have not been established. This study investigated optimal methods for continuous OCT imaging. METHODS: Thirty-four arteries with stent implantation (24 peripheral and 10 coronary arteries)in 14 pigs were examined using OCT with a motorized pullback device. Two imaging methods (flush alone by liquid substance and flush with occlusion) were compared. Adequate image acquisition was defined as the entire circumferential intimal layer being detectable within continuous segments. To investigate factors that could influence image quality, stented regions were divided into 4-5 mm segments. RESULTS: The flush with occlusion method provided better OCT images compared to flush alone (flush with occlusion: 60.9%, flush alone: 8.7%, p = 0.0002). Using the flush with occlusion method, the rate of adequate image acquisition was 64.4% and visualization of > 75% intimal circumference was 83.5%. Intravascular ultrasound could detect all stented regions. Segmental analyses found more adequate images were detected in smaller vessels (adequate segment: 3.8 +/- 0.4 mm, inadequate segment: 4.2 +/- 0.8 mm, p < 0.0001) or with centered image wire position (adequate segment: center 35%, inadequate segment: center 14%, p = 0.003). In addition, side branches did not affect image quality. CONCLUSIONS: To acquire continuous OCT images, the flush with occlusion method was more effective compared to flush alone. Moreover, image quality is affected by vessel size and imaging wire position. These results suggest that optimized OCT imaging can provide continuous vessel detection.

Animals↗