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Biomedical subjects

Y Ikari

Publications and source records attributed to Y Ikari.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effects of cilostazol on late lumen loss after Palmaz-Schatz stent implantation.

Cilostazol inhibits intimal hyperplasia after stent implantation into canine iliac arteries. To determine the antiproliferative effect of this agent, cilostazol or aspirin was randomly given for 6 mo to 36 patients treated with Palmaz-Schatz stent implantation. Initial success was obtained in 34 patients. Repeat angiography was performed in 33 patients, and the complete angiographic data were obtained in 22 lesions of the cilostazol group and in 21 lesions of the aspirin group. The reference diameter and minimal luminal diameter were similar in both groups before and immediately after stent implantation. At follow-up, minimal luminal diameters were significantly greater in the cilostazol group than in the aspirin group (P < 0.001). Late loss and loss index were significantly smaller in the cilostazol group than in the aspirin group (P < 0.001). These results suggest that cilostazol reduces angiographic late lumen loss and thereby may reduce the incidence of restenosis after Palmaz-Schatz stent implantation.

Aged↗
PubMed1998

Tyrosine phosphorylation of platelet derived growth factor beta receptors in coronary artery lesions: implications for vascular remodelling after directional coronary atherectomy and unstable angina pectoris.

BACKGROUND: Growth factors such as platelet derived growth factor (PDGF) have been postulated to be important mediators of neointimal proliferation observed in atherosclerotic plaques and restenotic lesions following coronary interventions. Binding of PDGF to its receptor results in intrinsic receptor tyrosine kinase activation and subsequent cellular migration, proliferation, and vascular contraction. AIMS: To investigate whether the concentration of PDGF beta receptor tyrosine phosphorylation obtained from directional coronary atherectomy (DCA) samples correlate with atherosclerotic plaque burden, the ability of diseased vessels to remodel, coronary risk factors, and clinical events. METHODS: DCA samples from 59 patients and 15 non-atherosclerotic left internal thoracic arteries (LITA) were analysed for PDGF beta receptor tyrosine phosphorylation content by receptor immunoprecipitation and antiphosphotyrosine western blot. The amount of PDGF beta receptor phosphorylation was analysed in relation to angiographic follow up data and clinical variables. RESULTS: PDGF beta receptor tyrosine phosphorylation in the 59 DCA samples was greater than in the 15 non-atherosclerotic LITA (mean (SD) 0.84 (0.67) v 0.17 (0.08) over a control standard, p < 0.0001). As evaluated by stepwise regression analysis, incorporation of both PDGF beta receptor tyrosine phosphorylation and immediate gain correlated strongly (adjusted r2 = 0.579) with late loss, although PDGF beta receptor tyramine phosphorylation alone correlated poorly with late loss. Multivariate regression analysis of coronary risk factors and clinical events revealed unstable angina as the most significant correlate of PDGF beta receptor tyrosine phosphorylation (F value 20.009, p < 0.0001). CONCLUSIONS: PDGF beta receptor tyrosine phosphorylation in atherosclerotic lesions is increased compared with non-atherosclerotic arterial tissues. The association of PDGF beta receptor tyrosine phosphorylation with immediate gain strongly correlates with vascular remodelling. PDGF beta receptor tyrosine phosphorylation correlates with unstable angina pectoris.

Angina, Unstable↗
PubMed1997

Patency of intermediate size side branches after Palmaz-Schatz stent implantation.

The immediate and long-term patency of intermediate size side branches was assessed by serial coronary angiography in 47 patients with 48 lesions to determine whether the presence of these side branches (1-2 mm in diameter) is unsuitable for Palmaz-Schatz stent implantation. Coronary angiography was performed at baseline, after conventional balloon angioplasty, immediately after stent implantation, at 1 week, and at 6-month follow-up. Sixty-eight lesion-associated side branches that were 1-2 mm in diameter, 11 with branch ostial stenosis (Group A) and 57 without ostial stenosis (Group B) were studied. After stent implantation, 9 (13%) branches became totally occluded and coronary flow deteriorated in 13 branches (19%). The incidence of side branch occlusion during the procedure in group A was greater than in group B (55% vs. 12%; p < 0.005). One (2%) patient suffered persistent chest pain, but no procedure was complicated by Q-wave myocardial infarction or significant elevation of creatine kinase concentration. Flow improved in 82% of the occluded side branches after 1 week and in 90% after 6 months. These results suggest that the presence of intermediate size side branches is not a contra-indication to Palmaz-Schatz stent implantation.

Angioplasty, Balloon, Coronary↗
PubMed1996

Thrombotic occlusion of the coronary artery associated with accidental detachment of undeployed Palmaz-Schatz stent.

We describe a case of coronary stenting in which accidental detachment of the Palmaz-Schatz stent induced thrombotic occlusion of the coronary artery. This case suggests that careful consideration of the risk involving coronary occlusion is mandatory on deciding the therapeutic strategy of the cases in which the unexpanded coronary stent cannot be retrieved following successful deployment.

Adult↗
PubMed1996

Aortic dissection during directional coronary atherectomy.

Directional coronary atherectomy has been applied to aorto-ostial lesions with higher success and lower complication rates than conventional balloon angioplasty. Aortic injuries have been reported with this technique, most resulting from the tip of the catheter. In this report, an aortic dissection caused by the shaft of the directional coronary atherectomy catheter is described.

Aortic Dissection↗
PubMed1996

Effects of competitive blood flow on arterial graft patency and diameter. Medium-term postoperative follow-up.

To identify predictors of arterial graft patency, we followed up 30 internal thoracic arterial grafts and 23 right gastroepiploic arterial grafts in situ with patency documented during postoperative angiography. After 24 months of follow-up on average, repeat angiography detected that one internal thoracic artery and two gastroepiploic arteries were anatomically occluded and that the other three gastroepiploic arteries were nonfunctioning. The logistic regression model identified a relationship between graft patency and competitive flow, which was detected as stenosis in the recipient coronary arteries (coefficients, p < 0.05; model, Hosmer-Lemeshow chi2 statistic 3.59, p = 0.89). The linear regression model demonstrated that changes in graft luminal diameter correlated with competitive flow (p < 0.01), smoking history (p < 0.05), and type of arterial grafts (p < 0.001) (R2 = 0.40, adjusted R2 = 0.36). The findings suggest a temporal relationship between competitive flow and prognosis of arterial graft.

Abdominal Muscles↗
PubMed1996

Prolonged luminal narrowing of internal mammary artery graft after percutaneous transluminal angioplasty.

The authors describe a case with an internal mammary artery (IMA) graft that demonstrated prolonged, but reversible, luminal narrowing persisting > twenty-four hours following percutaneous transluminal angioplasty. Luminal narrowing disappeared spontaneously, however, at the time of follow-up angiography one week after the angioplasty. Since haziness at the dilation site had been shown on preprocedural angiogram, suggestive of intraluminal thrombus, this phenomenon may be attributed to either prolonged vasospasm or distal embolization of the IMA graft.

Angioplasty, Balloon, Coronary↗
PubMed1996

Comparison of aortic valve replacement and percutaneous aortic balloon valvuloplasty for elderly patients with aortic stenosis.

The outcome of aortic balloon valvuloplasty (ABV) was compared with that of aortic valve replacement (AVR) in aortic stenosis (AS) patients more than 60 years old. The indications for ABV included low respiratory and renal function, cancer, the patient's refusal of surgery, and low daily activity. Twenty six patients underwent AVR and 13 underwent ABV. Initially, the AVR group was younger and more symptomatic than the ABV group. Two perioperative deaths occurred in the AVR group, while there were none in the ABV group. Twenty-four AVR patients and 12 ABV patients had a successful outcome, with remarkable pressure gradient reduction in both groups. In the follow-up, only 1 death and no cardiac events were detected in the AVR group (mean follow-up of 27 months), whereas 3 deaths, 6 heart failures, 2 repeated ABV, and 4 AVR were seen in the ABV group (mean follow-up of 10 months). The data showed that ABV was safer than AVR, but a higher rate of restenosis limited its efficacy. In the ABV group, a higher ratio of balloon size to aortic diameter correlated with longer event-free survival. We concluded that for elderly AS patients, ABV should be used only in those with high surgical risk as a palliative therapy or a bridge therapy to AVR, and AVR should be primarily recommended under rigid evaluation of the patient's physical status.

Aged↗
PubMed1995

Luminal loss and site of restenosis after Palmaz-Schatz coronary stent implantation.

Restenosis has frequently been observed at the articulation of the Palmaz-Schatz stent. However, the precise mechanism for this remains poorly understood. We measured the luminal diameter in 5 segments within the stent in 67 lesions of 63 patients with successful stenting. Luminal diameter at all 5 sites was significantly reduced 6 months after stent implantation (3.2 +/- 0.5 vs 2.4 +/- 0.7 mm, p < 0.05). Angiographic restenosis rate was 18%. Restenosis involving the articulation was found in 75% of the lesions, and that involving the articulation or edges in 83%. The diameter at the articulation was significantly smaller both immediately (3.0 +/- 0.5 mm vs 3.3 +/- 0.5 mm, p < 0.05) and 6 months after (2.1 +/- 0.8 mm vs 2.5 +/- 0.7 mm, p < 0.05) stenting than the diameter of other stent segments. The loss index was significantly greater at the proximal and distal edges than at the bodies of the stent (0.98 vs 0.60, p < 0.05). The edges of the Palmaz-Schatz stent tend to dilate more than the body of the stent during normal inflation. Although this anchoring system protects against dislodgment or migration of the stent, it may cause more injury. The articulation has 2 anchoring edges within only a 1 mm diameter. Thus, restenosis at the articulation may be ascribed to residual stenosis, increased intimal proliferation due to more severe injury, and delayed late vessel remodeling from lack of mechanical support. These characteristics may be attributed to stent design, and design improvement of the articulation may lead to more favorable results after stent implantation.

Aged↗
PubMed1995

Repeat embolization of the side branch of the internal mammary artery graft by gelatin sponge particles and micro coils.

The internal mammary artery (IMA) is increasingly used as a coronary bypass conduit because of better long-term patency and improved prognosis as compared with venous grafts. Previous investigators have suggested that the "steal" of blood flow of the IMA graft via the subclavian artery or a persistent large side branch of the graft may lead to its thinning. However, only a few reports have described the embolization of a large side branch using a transcatheter procedure. We present a case of repeated embolization of a large lateral costal side branch of the left internal mammary arterial graft applying gelatin sponge particles and micro coils, as well as angioplasty to the graft conduit, with resulting easing of chest pain.

Aged↗
PubMed1995

Intracoronary stenting of a coronary occlusion resulting from an aortic dissection.

Acute myocardial infarction secondary to aortic dissection may occur due to compression of the coronary arteries by a hematoma or extension of the dissection into the coronary arterial wall. We report a patient with this condition who was successfully treated by Palmaz-Schatz stenting, providing an alternative to thrombolysis or angioplasty.

Aortic Dissection↗
PubMed1995

Leser-Trélat sign associated with Sézary syndrome.

A 74-year-old Japanese male had developed generalized erythroderma and rapid growth of multiple verrucous lesions over the entire surface of his face, trunk, and extremities three months before he was seen. Histologically seborrheic keratoses were revealed. Laboratory examinations showed peripheral leukocytosis with atypical lymphocytes and high levels of IgE and IgG. On the basis of these clinical and histopathologic findings, we diagnosed the patient as having Leser-Trélat sign associated with Sézary syndrome. The erythroderma subsided after administration of oral predonisone, and no new formations of seborrheic keratosis were observed. However, because of subsequent aggravation of the generalized erythroderma, we administered chemotherapy. Six months after the initial examination, lung cancer was found, and the patient subsequently died of respiratory and renal failure.

Aged↗
PubMed1995

Initial and subsequent angiographic outcome of percutaneous transluminal angioplasty performed on internal mammary artery grafts.

OBJECTIVE: To estimate the initial outcome and incidence of restenosis of angioplasty of internal mammary artery grafts in a retrospective study. METHODS: The study population consisted of 46 patients (48 lesions) who underwent first balloon angioplasty within the internal mammary artery graft. Most (37/48) were at the distal anastomosis. A few (8/48) were in the graft body. Six patients with the evidence of angiographic restenosis underwent a second angioplasty. RESULTS: The success rate and the restenosis rate of the first angioplasty was 73% and 30% respectively. Of the 34 patients (35 lesions) with a successful first angioplasty, 30 underwent follow up angiography with a restenosis rate of 30% (9/30). A second angioplasty was performed on six of the nine restenotic lesions, with a success rate of 83% and no restenoses. The percent diameter stenosis of the recipient native coronary artery was significantly greater in the restenosis group, at 75 (SD 27)% v 89 (17)%, p < 0.05. CONCLUSIONS: First angioplasty of 46 patients (48 lesions) within an internal mammary artery graft was performed with a success rate of 73% and a restenosis rate of 30% (follow up rate of 88%). The extent of the stenosis of the recipient native coronary artery may affect the restenosis rate.

Adult↗
PubMed1995

Short-term outcome and long-term follow-up of percutaneous coronary intervention in patients aged 40 years or younger.

Forty five patients aged 40 years or younger were treated with coronary intervention in our institution between 1983 and 1994. This young Japanese population had a strong predisposition to risk factors but did not have extensive disease. These patients underwent 50 elective interventional procedures for angina pectoris or old myocardial infarction and 6 direct balloon angioplasty procedures for acute myocardial infarction. The initial successful result was obtained in 41 of the 45 patients (91%). The mean follow-up was 43 +/- 35 months. Angiographic follow-up was available in 31 of the 41 eligible patients (76%). Angiographic restenosis was seen in 9 of these 31 patients (29%), and in 12 of the 38 lesions (32%) with initial successful intervention. There were no deaths among the successfully treated patients. Event-free survival rate without death, myocardial infarction, or coronary artery bypass surgery was 94%; however, event-free survival rate without death, myocardial infarction, coronary artery bypass surgery, or repeat intervention was 66% at 43 months. Ninety three percent of the eligible patients were free from angina at follow-up. These short- and long-term results suggest that young Japanese patients can be treated safely and effectively with coronary interventions.

Adult↗
PubMed1994

Angiographic follow-up of patients after transluminal coronary extraction atherectomy.

The transluminal coronary extraction-endarterectomy catheter (TEC) consists of a torquing tube with a distal, conical rotating blade. We successfully treated 26 patients (27 lesions) using this catheter with adjunctive balloon angioplasty. Twenty-five patients (26 lesions) had serial angiography before, 1 day after, and 3 months after the procedure. All 17 patients without restenosis 3 months after the procedure had angiography at 6 months. Restenosis, defined as > 50% diameter stenosis, was noted in nine lesions at 3 months (early restenosis) and in five lesions at 6 months (late restenosis). Between vessels with and without early restenosis, the percentage of diameter stenosis seen 1 day after the procedure and the luminal diameter were significantly different (38% +/- 14% vs 22% +/- 12%, respectively, p < 0.01; 2.3 vs 2.9 mm, p < 0.01, respectively). However, between vessels with and without late restenosis, these variables were not significantly different. The overall restenosis rate was 54% (native vessels 50%; grafts 80%). This observational study suggests that very early diameter narrowing seen 1 day after the procedure has greater contribution to early restenosis than to late restenosis after successful TEC atherectomy with adjunctive balloon angioplasty.

Aged↗