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Masahiko Shimizu

Publications and source records attributed to Masahiko Shimizu.

13 recordsLinked to original sources
PubMed2005

Relation of C-reactive protein and one-year survival after acute myocardial infarction with versus without statin therapy.

We evaluated the interaction between inflammation and survival benefit from statin therapy in patients who had acute myocardial infarction. Although 1-year mortality did not differ between patients who used statin therapy and those who did not, among patients who had C-reactive protein (CRP) concentrations in the lower 2 tertiles (<2.9 mg/L), 1-year mortality was higher in patients who used statin therapy than in those who did not within the highest CRP-defined tertile (> or =2.9 mg/L). Statin therapy significantly decreased the hazard ratio for 1-year mortality in patients who had high CRP levels to approximately the hazard present for patients who had low CRP levels and did not receive statin therapy.

C-Reactive Protein↗
PubMed2005

Distal protection improved reperfusion and reduced left ventricular dysfunction in patients with acute myocardial infarction who had angioscopically defined ruptured plaque.

BACKGROUND: Distal protection, in the Saphenous Vein Graft Angioplasty Free of Emboli (SAFER) trial, is demonstrated to prevent distal embolism in the percutaneous coronary intervention of saphenous vein graft. However, in the Enhanced Myocardial Efficacy and Recovery by Aspiration of Liberated Debris (EMERALD) trial, it was not effective in the percutaneous coronary intervention of native coronary arteries in patients with acute myocardial infarction (AMI). We hypothesized that its effectiveness would be determined by lesion characteristics. Therefore, we classified the type of culprit lesion by angioscopy and examined its influence on the effectiveness of distal protection, comparing patients with AMI treated with and without distal protection. METHODS AND RESULTS: Consecutive patients with AMI treated without distal protection (n=110) from July 2000 to July 2002 and those treated with distal protection (n=81) from July 2002 to July 2004 were included. Patients in each group were subdivided according to whether or not they had angioscopically defined ruptured plaque at culprit lesion. Among those groups, incidence of no-reflow phenomenon, ST-segment resolution, myocardial blush grade, and left ventricular ejection fraction at 6 months were compared. Aspirated samples by distal protection were semiquantitatively and histologically analyzed and compared between patients with and without ruptured plaque. No-reflow phenomenon was most frequently (P<0.05) observed in patients with ruptured plaque treated without distal protection. ST-segment resolution (68+/-15% versus 40+/-21%, P<0.001), myocardial blush grade (2.6+/-0.5 versus 1.8+/-0.3, P<0.001), and left ventricular ejection fraction (47.2+/-6.7% versus 41.0+/-9.7%, P<0.01) were improved by distal protection among patients with ruptured plaque but not among patients without ruptured plaque. Aspirated samples >1 mm were detected more frequently (97.3% versus 78.5%, P<0.05) in patients with ruptured plaque than those without ruptured plaque. Histologically, aspirated samples contained plaque debris (95.3% versus 31.1%, P<0.05) more frequently in patients with ruptured plaque than in those without ruptured plaque. CONCLUSIONS: Distal protection reduced microcirculation damage and left ventricular dysfunction in patients with AMI who had angioscopically defined ruptured plaque. Distal embolization of plaque debris was detected more frequently in patients with ruptured plaque. These results suggest that microcirculation damage and left ventricular dysfunction are increased mainly by distal embolization of plaque debris rather than of thrombus.

Biopsy, Needle↗
PubMed2005

Impact of atherosclerosis-related gene polymorphisms on mortality and recurrent events after myocardial infarction.

Although previous epidemiologic studies have suggested an association between the onset of myocardial infarction (MI) and some genetic variations, the impact of these variants on recurrent cardiovascular events after MI has not been fully elucidated. We genotyped 87 polymorphisms of 73 atherosclerosis-related genes in consecutive acute MI patients registered in the Osaka Acute Coronary Insufficiency Study and compared the incidence of death and major adverse cardiac events (MACE) among the polymorphisms of each gene. After initial screening in 507 patients, we selected nine polymorphisms for screening in all 1586 patients. Multivariate Cox regression analysis revealed that G allele carriers at the position 252 of the lymphotoxin alpha (LTA) gene were independently associated with an increased risk of death (hazard ratio [HR]: 2.46; 95% CI: 1.24-4.86). In conclusion, a 252G allele of LTA is associated with an increased risk of death after AMI and may be a useful genetic predictor.

Atherosclerosis↗
PubMed2005

Association between cardiac troponin T elevation and angioscopic morphology of culprit lesion in patients with non-ST-segment elevation acute coronary syndrome.

BACKGROUND: It is well known that cardiac troponin T (TnT) elevation on admission indicates a high-risk subgroup among patients with non-ST-segment elevation acute coronary syndrome (NSEACS). Although the mechanism of TnT elevation is speculated to be the microthromboembolism from unstable plaques, it has not been clarified. The aim of this study is to clarify the association between the serum TnT elevation and the angioscopically evaluated morphology of culprit lesion in the patients with NSEACS. METHODS: Among 113 patients with NSEACS who had significant coronary stenosis, 62 patients with successful angioscopic examination were prospectively and consecutively enrolled from October 2001 to August 2002. Patients were divided into 2 groups according to the serum TnT level measured before percutaneous coronary intervention: TnT-positive or TnT-negative group. Thrombus and plaque color at culprit lesion were evaluated by angioscopy and were compared between the groups. Plaque color was determined as yellow or white, and thrombus as none, small, or large. Three different definitions for TnT-positive (> or =0.1, > or =0.03, and > or =0.01 ng/mL) were used and the sensitivity and specificity for detecting thrombus was compared. RESULTS: Prevalence of thrombus, large thrombus, and yellow plaque were all higher in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Angiographic slow-flow occurred more frequently after percutaneous coronary intervention in TnT-positive than in TnT-negative group for 3 different cutoff values of TnT. Sensitivity/specificity of detecting large thrombus were 33%/100%, 44%/91%, and 56%/83% when TnT-positive was defined as TnT > or = 0.1, > or =0.03, and > or =0.01 ng/mL, respectively. CONCLUSIONS: Serum TnT level was significantly associated with the prevalence of thrombus and yellow plaque at the culprit lesions of NSEACS. Troponin T, when positive was defined as > or =0.01 ng/mL, still have a high specificity for detecting intracoronary thrombus.

Aged↗
PubMed2005

Influence of serotonin transporter gene polymorphism on depressive symptoms and new cardiac events after acute myocardial infarction.

BACKGROUND: In patients with acute myocardial infarction (AMI), depressive symptoms increase the risk for cardiac events. Recently, the S allele of the serotonin transporter (5-HTT) gene-linked polymorphic region was shown to reduce transcription of this gene and thus reduce serotonin reuptake, and this allele is linked with depressive symptoms as well as other psychiatric diseases. However, the influence of the S allele on depressive symptoms and cardiac events after AMI is unclear. METHODS: To investigate whether the S allele was associated with depressive symptoms and cardiac events after AMI, we prospectively examined depressive symptoms and new cardiac events in 2509 genotyped patients with AMI. RESULTS: Depressive symptoms were more common in patients with the S allele than in those without it (48.3% vs 35.0%, P = .02). Multivariate analysis revealed that the S allele was independently associated with depressive symptoms (odds ratio 2.19, 95% confidence interval [CI] 1.21-3.98, P = .01). Cardiac events (cardiac death, revascularization, heart failure, reinfarction, arrhythmia, and unstable angina) were more frequent in patients with the S allele than in those without it (31.3% vs 22.3%, P = .046). Multivariate Cox regression analysis revealed an association between the S allele and an increased risk for cardiac events (hazard ratio [HR] 1.69, 95% CI 1.03-2.78, P = .04). However, the HR became insignificant after an adjustment for depressive symptoms (HR 1.30, 95% CI 0.84-2.01, P = .24). CONCLUSIONS: The S allele in the 5-HTT gene-linked polymorphic region is associated with an increased risk for subsequent cardiac events, which is mediated, at least in part, by the depressive symptoms in patients after AMI.

Depression↗
PubMed2005

Identification of uncomplicated patients with acute myocardial infarction undergoing percutaneous coronary intervention: are these patients suitable for early discharge?

BACKGROUND: The hospital stay after acute myocardial infarction (AMI) is still extremely long in Japan and does not correspond with disease severity. The purpose of the present study was to identify a subgroup of AMI patients suitable for early discharge. METHODS AND RESULTS: A total of 3,739 AMI patients treated with percutaneous coronary intervention (PCI) within 24 h after onset, who enrolled Osaka Acute Coronary Insufficiency Study between April 1998 and March 2004, were studied. Patients showing no complications within the first 7 days (n=1,786) were considered to be eligible for early discharge. In these patients, multivariate logistic regression analysis selected prior myocardial infarction, left anterior descending coronary artery disease and failed PCI as independent predictors of major complications from day 8 to discharge. Patients without any predictor had significant lower rates of major complications from day 8 to 6 months after discharge than those with 1 or more predictors. Furthermore, in the present study there were no deaths in patients without any predictors. CONCLUSION: Patients who either do not have serious complications during the first 7 days or any predictor are at very low risk of major complications from day 8 to 6 months after discharge. These carefully selected patients may be suitable for early (day 8) hospital discharge after AMI.

Acute Disease↗
PubMed2005

Impact of smoking status on long-term mortality in patients with acute myocardial infarction.

BACKGROUND: Cessation of smoking after a cardiovascular event has been shown in Western countries to have a beneficial effect on clinical events during long-term follow-up. However, knowledge of the effect of smoking status after acute myocardial infarction (AMI) on the long-term mortality based on a large-scale sample is still limited in Japan. METHODS AND RESULTS: In the present study 2,579 AMI patients were enrolled in the Osaka Acute Coronary Insufficiency Study (OACIS) between April 1998 and March 2003. Smoking status was assessed at baseline and 3 months after hospital discharge by mailed questionnaire. Patients were divided into nonsmokers (n=823), former smokers (those who had stopped smoking before AMI onset, n=332), quitters (those who stopped smoking after AMI onset, n=1,056), and persistent smokers (those who smoked before and after AMI, n=368). Quitters had lower long-term mortality rates than persistent smokers (3.0% vs 5.2%; log rank, p=0.032). Multivariate Cox regression analysis revealed that smoking cessation was independently associated with a reduction in risk of long-term mortality (hazard ratio, 0.39; 95% confidence interval, 0.20-0.77). CONCLUSIONS: Patients who continue to smoke after AMI are at greater risk for death than patients who quit smoking. Cessation of smoking benefits the long-term prognosis in patients with AMI.

Angina Pectoris↗
PubMed2004

Reduced collateral circulation to the infarct-related artery in elderly patients with acute myocardial infarction.

OBJECTIVES: The purpose of this study was to investigate the hypothesis that circulation via collateral vessels to an infarct-related artery (IRA) is impaired with aging in patients with acute myocardial infarction (AMI). BACKGROUND: Animal experiments have shown that advanced age blunts the development of new vessels in response to angiogenic cytokines. METHODS: Of 3,573 consecutive patients with AMI, 1,934 patients who fulfilled the following criteria were enrolled in this study: 1) coronary angiograms were obtained within 72 h after the onset of AMI; and 2) IRA showed complete occlusion (Thrombolysis In Myocardial Infarction [TIMI] flow grade 0 or 1). Collaterals to the IRA were angiographically evaluated using the Rentrop score. Rentrop scores 1 to 3 were defined as demonstrating significant collaterals. RESULTS: The prevalence of collaterals decreased with age, from 47.9%, 45.8%, 43.4%, to 34.0% in patients <50 years, 50 to 59 years, 60 to 69 years, > or =70 years, respectively (p < 0.001). Advanced age was an independent factor predicting the absence of collateral circulation to the IRA. In contrast, time to catheterization, history of angina pectoris, and preinfarction angina were independent predictors for the presence of collaterals. Multivariate analysis showed that the absence of collaterals was an independent predictor of in-hospital mortality in elderly patients > or =70 years (odds ratio, 15.6; 95% confidence interval, 3.5 to 69.6), although this finding was not significant in patients <70 years. CONCLUSIONS: Advanced age is associated with decreased angiographic presence of collaterals to the IRA in patients with AMI. This abnormality may contribute to the poor prognosis of elderly patients with AMI.

Age Factors↗
PubMed2004

Assessment of plaque vulnerability by angioscopic classification of plaque color.

BACKGROUND: The disruption of yellow plaque and subsequent thrombosis is regarded as the mechanism of acute coronary syndrome. However, there are limited reports on the assessment of plaque vulnerability. Therefore, we tested whether the angioscopically determined yellow color intensity of plaque is associated with the prevalence of thrombosis on the plaque. METHODS: The angioscopic images of 843 patients who underwent catheterization and angioscopic examination from November 1999 to July 2003 for the diagnosis of coronary artery diseases were analyzed. Suspected culprit vessel was observed by angioscopy, and the yellow color intensity (1, light yellow; 2, yellow; 3, intensive yellow) of all yellow plaques (n = 1253) detected in the nonstenotic (diameter stenosis <50%) coronary segments was determined, as well as whether there was thrombosis on the plaques. RESULTS: The number of detected yellow plaques was 345, 721, and 187 for color grade 1, 2, and 3, respectively. The prevalence of thrombosis detected by angioscopy (15%, 26%, and 52% on the plaque of color grade 1, 2, and 3, respectively, P <.0001) was significantly higher on the plaque of higher yellow color grade. CONCLUSIONS: The yellow color intensity of plaque determined by angioscopy was strongly related with the prevalence of thrombosis on the plaque. The yellow color intensity may be a marker of plaque vulnerability.

Aged↗
PubMed2004

Color of culprit lesion at 6 months after plain old balloon angioplasty versus stenting in patients with acute myocardial infarction.

BACKGROUND: Although the healing process of disrupted yellow plaques at myocardial infarction (MI) culprit lesions has been reported, the effect of stenting on this process has not been clarified. Stenting has been reported to deteriorate the endothelial function after percutaneous coronary intervention (PCI). Therefore, we compared the angioscopic morphology of culprit lesions at 6 months after plain old balloon angioplasty (POBA) and stenting to clarify the effect of stenting on the healing of disrupted culprit plaques of acute MI. METHODS: Patients with acute MI who had yellow culprit plaque, successful reperfusion therapy with POBA (n = 21) or stenting (n = 22), and a successful 6-month follow-up angioscopic examination were included in this study. Oral ticlopidine (200 mg/day) was administered for 3 to 6 months after stenting. RESULTS: At 6 months after reperfusion therapy, the color of the culprit lesion became white in significantly more patients treated with stenting than treated with POBA (50% vs 14%; P = .01). However, the prevalence of thrombus appeared to be higher in patients treated with stenting than in patients treated with POBA (27% vs 5%; P = .04). Although there was some difference in the patients' characteristics in the groups, logistic regression analysis revealed no significant influence of those factors on the color of or on the prevalence of thrombus at the culprit lesion. CONCLUSIONS: Coronary stenting in patients with acute MI leads to the disappearance of yellow color at a significantly higher rate than POBA; however, whether it stabilizes the plaque requires further investigation.

Angioplasty, Balloon, Coronary↗
PubMed2004

Predictors of length of hospital stay after acute myocardial infarction in Japan.

BACKGROUND: In Western countries, the length of hospital stay after acute myocardial infarction (AMI) has decreased dramatically during the past 3 decades and is now approximately 1 week. However, epidemiological data concerning the length of hospital stay, its predictors and trends based on a large-scale sample are still limited in Japan. METHODS AND RESULTS: The study group comprised 4,113 surviving AMI patients who were enrolled in the Osaka Acute Coronary Insufficiency Study from April 1998 to March 2003. The mean length of hospital stay was 31.2 days. Clinical factors (patient characteristics, severity of infarction, therapy, and in-hospital complications) only explained 26% of the variation in hospital stay. The mean hospital stay was significantly longer in 1998 than in 2002. In 2002, occupational status and admission to a high-volume hospital were independent predictors of a shorter hospital stay, but this association was not observed in 1998. CONCLUSIONS: The hospital stay is still extremely long in Japan and clinical factors do not provide an explanation. The findings of the present study suggest that the hospital stay could be reduced in some patients with AMI, but randomized studies are needed to examine the feasibility of early discharge.

Aged↗
PubMed2002

Postoperative changes in angiographically normal saphenous vein coronary bypass grafts using intravascular ultrasound.

We examined the process of vessel wall thickening in angiographically normal saphenous vein grafts (SVGs) using intravascular ultrasound. Fifteen SVGs were studied in the early stage (within 1 month postoperatively) and 14 SVGs in the late stage (over 6 months postoperatively). Lumen cross-sectional area (CSA) and vessel CSA were measured. Vessel wall area (VWA) was calculated and %VWA was defined as VWA / vessel CSA. Vessel CSA, VWA, and %VWA were significantly larger in the late stage than in the early stage (28.8 vs 21.6 mm(2), 15.8 vs 5.3 mm(2), 55.7% vs 24.9%, respectively) and lumen CSA was smaller in the late stage (12.8 vs 16.2 mm(2)). VWA correlated with vessel CSA, but not with lumen CSA. The time course of %VWA showed that %VWA in the late stage was a plateau state. From these findings, we concluded that the wall thickening process in SVGs begins within 6 months postoperatively and is accompanied by compensatory vessel enlargement.

Aged↗