Biomedical subjects

Kenei Shimada

Publications and source records attributed to Kenei Shimada.

28 records · Page 2Linked to original sources

PubMed2004

Impact of HMG-CoA reductase inhibitors for non-treated coronary segments.

BACKGROUND: HMG-CoA reductase inhibitors (statin) have been reported to decrease coronary artery events in several angiographic studies. However, the mechanism by which statin achieve this is still unclear. The purpose of this study was to identify the effect of statin on coronary plaque using serial intravascular ultrasound analysis. METHODS AND RESULTS: In this study, 48 patients with 48 lesions were divided into the prescribed group (statin group, n = 22) or the non-prescribed group (control group, n = 26) after successful coronary artery stenting. IVUS images were obtained at consecutive 5 mm segments, 5 mm from the proximal stent edge, immediately after stenting and at 6 months follow up. External elastic membrane volume (EEMV), lumen volume (LV) and plaque volume (PV) were measured using Simpson's method. The control group revealed no significant serial change in EEMV, PV, and LV during 6 months. On the other hand, the statin group revealed significant reductions of PV (35.5 +/- 12.7 mm3 vs 30.9 +/- 15.6 mm3, p = 0.001), resulting in increase of LV (47.7 +/- 19.8 mm3 vs 52.5 +/- 22.2 mm3, p = 0.003) without EEMV change (82.8 +/- 21.8 mm3 vs 83.9 +/- 25.7 mm3, p = NS). Although percent EEMV and percent LV changes showed no differences between the two groups, a larger percent PV change was observed in the statin group compared to the control group (control; 5.8 +/- 20.3% vs statin; -20.4 +/- 21.8%, p = 0.02). CONCLUSION: The results of this study suggest that statin administration for 6 months reduces coronary plaque without positive vessel remodeling.

Aged↗

PubMed2004

The impact of IVUS guided bare metal stent implantation for non-small vessel.

UNLABELLED: Previous studies have shown larger target vessel or greater stent area contribute to reduced restenosis rate. Thus, intravascular ultrasound (IVUS)-guided bare metal stent (BMS) implantation for selected lesions might achieve drug-eluting stent-like outcomes. The aim was to examine the long-term outcomes of BMS using IVUS-guided optimization. METHODS: Consecutive 103 coronary artery lesions suitable for IVUS were enrolled. Using IVUS, final stent balloon size selected was 90 percent of media-to-media diameter at the lesion or distal reference. The balloon size was listed as follows: group A (3.0-3.5 mm, n = 15), group B (3.5-3.75 mm, n = 64), and group C (3.75-4.5 mm, n = 24). RESULTS: At post-intervention, average stent area increased by the balloon size (A: 7.2 +/- 1.4 mm2, B: 8.9 +/- 1.5 mm2, and C: 12.1 +/- 2.0 mm2, respectively p < 0.001). At 6 month follow up, the average lumen area increased by balloon size (A: 4.1 +/- 1.7 mm2, B: 5.7 +/- 1.2 mm2, and C: 8.1 +/- 2.0 mm2, respectively p < 0.001). Accordingly, group B and C revealed lower restenosis, compared to group A (A: 46.7%, B: 10.9%, C: 8.3%, A vs B: p = 0.001; C vs A: p = 0.015). Moreover, target lesion revascularization was less in group B and C than group A (A 26.6%, B 3.1%, C 0%, A vs B: p = 0.011; C vs A: p = 0.017). CONCLUSIONS: For non-small vessels, IVUS-guided BMS implantation showed less restenosis and target lesion revascularization compared to small vessels, mainly due to larger initial gain. These study results suggest that IVUS-guided optimal BMS implantation for selected lesions might result in favorable long-term outcomes similar to those seen using drug-eluting stents. For a decade, coronary stenting has become a standard therapy for coronary artery disease due to favorable long-term outcomes and simple treatment procedure. Furthermore, for the last two years, drug-eluting stents (DES), releasing antiproliferative agents from bare metal backbone, revealed the restenosis rates less than half of those seen using conventional bare metal stents (BMS). While target lesions especially suitable for DES continue to be identified, earlier BMS studies showed that larger target vessel or greater stent area contributed to less restenosis. Thus, optimal IVUS-guided BMS implantation for selected lesions might achieve DES-like long-term outcomes. This study was designed to examine the long-term outcomes of BMS with intravascular ultrasound (IVUS)-guided optimization, using coronary angiography and IVUS data.

Aged↗

PubMed2003

Cut-off value of coronary flow velocity reserve by transthoracic Doppler echocardiography for diagnosis of significant left anterior descending artery stenosis in patients with coronary risk factors.

The purpose of this study was to evaluate the adequate cut-off value of coronary flow velocity reserve (CFVR) with transthoracic Doppler echocardiography for diagnoses of significant left anterior descending (LAD) artery stenosis in a large study population with various coronary risk factors. CFVR, which has been used for evaluation of significant coronary artery stenosis, can be reduced despite angiographically normal coronary arteries in patients with various coronary risk factors. However, the adequate cut-off value of CFVR for diagnosing significant LAD stenosis has not been fully established in patients with coronary risk factors. We examined 138 consecutive patients who underwent coronary angiography. Clinical histories of coronary risk factors were determined from interviews or medical records. CFVR assessment in the LAD artery by transthoracic Doppler echocardiography was performed in all patients. Of the 138 patients, 30 had significant stenosis, and the remainder had no stenotic lesions in the LAD artery. Receiver-operating characteristic curves for detection of significant LAD stenosis showed that a cut-off value of <2.0 was extremely precise. A cut-off value <2.0 of CFVR had a sensitivity of 90%, a specificity of 93%, a positive predictive value of 77%, and a negative predictive value of 97% for the presence of significant LAD stenosis. A cut-off value <2.0 of CFVR by transthoracic Doppler echocardiography was adequate for the diagnosis of significant LAD stenosis in a population that included patients with coronary risk factors.

Blood Flow Velocity↗

PubMed2003

In-stent restenosis and lesion morphology in patients with acute myocardial infarction.

We investigated the correlation between lesion morphology with preintervention intravascular ultrasound and in-stent restenosis in 72 patients with acute myocardial infarction (AMI). Multivariate logistic regression analysis showed that the presence of ruptured plaque was the only predictive factor of in-stent restenosis after primary stenting for AMI.

Aged↗

PubMed2003

C-reactive protein and lesion morphology in patients with acute myocardial infarction.

BACKGROUND: Elevated serum C-reactive protein (CRP) is of clinical significance in the management of acute coronary syndromes, but there have been few in vivo studies detailing the relation between lesion morphology and elevated CRP in the setting of acute myocardial infarction (AMI). In this study, we investigated the relation between lesion morphology as seen under preintervention intravascular ultrasound (IVUS) and CRP in the acute phase of AMI. METHODS AND RESULTS: Our patient population comprised 90 consecutive patients with AMI who underwent preintervention IVUS within 6 hours of the onset of symptoms. Patients were divided into an elevated CRP group (> or =3 mg/L) or a normal CRP group on the basis of serum CRP levels. There were no differences in patient characteristics or angiographic findings. We observed significantly more plaque rupture in the elevated CRP group than in the normal CRP group (70% versus 43%, P=0.01). A multivariate logistic regression model revealed that the presence of ruptured plaque alone correlated with elevation of serum CRP (P=0.02; odds ratio, 3.35; 95% CI, 1.22 to 9.18). CONCLUSIONS: Elevated CRP may be related to the presence of ruptured plaque. Our results suggest that in the setting of AMI, elevated CRP levels may reflect the inflammatory activity of a ruptured plaque.

Biomarkers↗

PubMed2003

Predicting angiographic distal embolization following percutaneous coronary intervention in patients with acute myocardial infarction.

The aim of this study was to investigate the relation between lesion morphology identified by intravascular ultrasound (IVUS) before intervention and angiographic distal embolization after percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). PCI for AMI has already been established as beneficial therapy, although some complications remain unresolved. Distal embolization is 1 of the important complications of PCI. Recently, some new devices have been developed for the prevention of distal embolization. However, few studies exist that look into the relation between lesion morphology and distal embolization. IVUS was performed safely in 140 consecutive patients with AMI before coronary intervention. No patient received thrombolytic therapy. From the incidence of angiographic distal embolization, patients were divided into 2 groups--an embolization group and a nonembolization group--and clinical background, IVUS, and angiographic information were evaluated. Distal embolization was observed in 12 patients (9%). Peak creatine kinase levels (3,877 +/- 2,285 vs 2,293 +/- 1,792 IU/L, p <0.05) and the incidence of angiographic thrombus (25% vs 5%, p <0.05) and intracoronary mobile mass detected by IVUS (75% vs 16%, p <0.001) were higher for patients in the embolization group. From the multivariate logistic regression analysis, only an intracoronary mobile mass detected by IVUS emerged as a predictor of distal embolization (odds ratio 53, 95% confidence interval 2.7 to 1,040, p <0.01). Patients with an intracoronary mobile mass detected by IVUS are prone to distal embolization after PCI and larger infarction. IVUS imaging before PCI may be useful for determining which patients need a distal protection device.

Aged↗

PubMed2003

Percutaneous transluminal angioplasty and stent placement for subclavian steal syndrome with concomitant anterograde flow in the left internal mammary artery graft for coronary artery bypass--case report.

A 63-year-old man presented with subclavian steal syndrome associated with left internal mammary artery (IMA) bypass graft to a coronary artery. He was admitted with a history of oppressive sensation in the chest, dizziness, and light headedness on exertion for 2 weeks in March 2002. He had undergone myocardial revascularization consisting of a left IMA-to-left anterior descending coronary artery graft in April 1988. His blood pressure was 140/70 mmHg in the right arm and 80/64 mmHg in the left arm. Aortic arch arteriography revealed complete occlusion of the left subclavian artery proximal to the left IMA takeoff and subclavian steal with anterograde flow of the left IMA. Percutaneous angioplasty and stent placement with protection of the left IMA bypass graft using a balloon catheter was successfully performed without complication by cerebral or myocardial ischemia. Complete recanalization of the occluded left subclavian artery and anterograde flow of the left vertebral artery were achieved. His symptoms disappeared and blood pressure in the left arm recovered. This variant of coronary subclavian steal might require protection of the left IMA during angioplasty and stent placement.

Angioplasty, Balloon↗

PubMed2002

No-reflow phenomenon and lesion morphology in patients with acute myocardial infarction.

BACKGROUND: The no-reflow phenomenon is associated with poor functional and clinical outcomes for patients with acute myocardial infarction (AMI). In the era of primary intervention, accurately identifying lesions at high risk of no reflow is of crucial importance. At present, no study into the relationship between lesion morphology and no reflow has been performed. The aim of this study was to investigate the relationship between preintervention intravascular ultrasound (IVUS) lesion morphology and the no-reflow phenomenon. METHODS AND RESULTS: This study comprised 100 consecutive patients with AMI who underwent preintervention IVUS and were successfully recanalized with primary balloon angioplasty or stenting. IVUS was again performed to identify and exclude any mechanical vessel obstruction in cases of thrombolysis in myocardial infarction flow grade 0, 1, or 2 after intervention in the absence of angiographic stenosis. Angiographic no reflow was seen in 13 patients (13%). Univariate analysis indicated that hypercholesterolemia, fissure and dissection, lipid pool-like image, lesion, and reference external elastic membrane cross-sectional area correlate with the no-reflow phenomenon. Multivariate logistic regression analysis showed that lipid pool-like image (P<0.05; odds ratio 118; 95% CI, 1.28 to 11 008) and lesion elastic membrane cross-sectional area (P<0.05; odds ratio 1.55; 95% CI 1.01 to 2.38) are independent predictive factors of no-reflow phenomenon after reperfusion for AMI. CONCLUSIONS: Large vessels with lipid pool-like image are at high risk for no reflow after primary intervention for AMI. Also, plaque content may play a role in damage to the microcirculation after primary intervention for AMI.

Angioplasty, Balloon, Coronary↗

PubMed2002

Short- and long-term outcomes of compromised side branches after Multi-Link stent implantation.

The Multi-Link stent is superior to other stents in terms of low rates of restenosis and target vessel revascularization. However, few data exist regarding short- and long-term outcomes for side branches after stenting. We evaluated short and long clinical outcomes and angiographic predictors of side-branch occlusion after the deployment of 137 Multi-Link stents. Thirty-four (25%) of the 137 side branches occluded immediately after stenting. We attempted reangioplasty for the side branches and our success rate was 85%. The incidence of side branches with intrinsic ostial disease was more than 50% before stenting and origination from the stented midsegment was a powerful angiographic predictor of side-branch occlusion. Side-branch patency is well maintained long-term. The incidence of restenosis within and near the stented segment of the parent vessel was 19%, and the incidence of target vessel revascularization was 15%. We recommend the use of Multi-Link stents regardless of the presence of side branches in the vicinity of the stenosis.

Aged↗

PubMed2002

Unruptured aneurysm of the sinus of valsalva with Behçet's disease.

A 52-year-old Japanese man who had suffered from Behçet's disease since the age of 45 years was admitted to hospital for evaluation of syncope and heart murmur. Echocardiography and aortography revealed severe aortic regurgitation and cystic masses under the right coronary cusp and the left ventricular outflow tract, but no shunt jet. He was diagnosed with unruptured aneurysm of the sinus of Valsalva, and surgical closure of the orifice of the aneurysm was performed. The diameter of the orifice was 11 mm and the aneurysm was 15 mm in depth, and consisted of 2 chambers. Because the aortic regurgitation was reduced after patch closure of the orifice, aortic valve replacement was not performed. Unruptured aneurysm of the sinus of Valsalva is a rare clinical lesion, but patients with active inflammatory disease of the aorta, such as in Behçet's disease, should have periodic echocardiography for early detection of an aneurysm or valvular involvement, even if there are not any symptoms.

Aortic Aneurysm↗