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Biomedical subjects

Takuro Takagi

Publications and source records attributed to Takuro Takagi.

16 recordsLinked to original sources
PubMed2006

MDCT detection of double right coronary artery arising from a single ostium in the right sinus of Valsalva: report of 2 cases.

Double right coronary artery arising from a single ostium in the right sinus of Valsalva is an extremely rare coronary artery variation. Differentiating this variation from high take off of a large right ventricular branch is often difficult in conventional coronary angiography. In two cases, multidetector-row computed tomography (MDCT) identified double right coronary artery. MDCT allows three-dimensional comprehension of the coronary artery anatomy and it is thought to be useful to distinguish this variation from a large right ventricular branch.

Abnormalities, Multiple↗
PubMed2004

Chronic stent recoil plays an important role in restenosis of the right coronary ostium.

OBJECTIVE: The efficacy of coronary stenting of aorto-ostial atherosclerotic lesions is still unclear. We investigated the frequency and mechanism of stent restenosis at this particular lesion. METHODS: Fifty-five consecutive patients with 64 native aorto-ostial lesions in the right coronary artery (RCA, n = 38) and the left main trunk (LM, n = 26) were treated by conventional stenting. Determinants of angiographic restenosis were established. The mechanism of stent restenosis was evaluated using post-stenting and follow-up intravascular ultrasound (IVUS) findings. RESULTS: Restenosis was more frequent in the RCA than in the LM (50% compared with 19%, P < 0.03) and determinants included diabetes mellitus (63% compared with 21%, P < 0.03), calcium deposition (58% compared with 5%, P < 0.003), smaller stent cross-sectional area (SA) (as demonstrated by post-stenting IVUS studies, 8.1 +/- 1.4 mm compared with 10.2 +/- 2.2 mm, P < 0.01), larger plaque burden (64 +/- 6% compared with 57 +/- 8%, P < 0.03) and less circular expansion at the aorto-coronary junction. Serial IVUS examination was performed in 11 patients with restenosis of the right coronary ostium. The mean reduction in the SA was 21% at the aorto-coronary junction (6.4 +/- 1.9 mm, P < 0.003), whereas the SA at the distal edge was unchanged. Thirty-three per cent of late luminal loss was due to chronic stent recoil. CONCLUSION: These findings suggest that stenosis of the right coronary ostium is a high-risk lesion for stent restenosis. In addition to excessive intimal growth, chronic stent recoil might be an important etiologic factor at this particular location.

Aged↗
PubMed2004

Insulin resistance in nondiabetic patients is associated with expansive remodeling in coronary arterial lesions.

OBJECTIVE: Insulin resistance has been implicated as an important initiating factor in coronary atherosclerosis. However, associations between insulin resistance and specific morphologic features of atherosclerotic coronary arteries remain unclear. We ultrasonographically evaluated the morphologic features of atherosclerotic coronary arteries in nondiabetic patients with insulin resistance. METHODS: Before intervention, 90 patients with 105 culprit lesions underwent intravascular ultrasound examination through which vessel area, lumen area and plaque area were evaluated. Expansive remodeling (lesion vessel area more than 5% greater than at the proximal reference segment) and constrictive remodeling (lesion vessel area more than 5% less than at the distal reference segment) were also evaluated. Insulin resistance was determined by homeostasis model assessment and defined as values above the 75th percentile (that is, 1.71). RESULTS: Insulin-resistant patients numbered 23, while nonresistant patients numbered 67. Culprit lesions in the insulin-resistant group showed larger vessel area (18.16 +/- 6.94 compared with 13.64 +/- 4.28 mm, P = 0.0001) and plaque area (16.64 +/- 6.78 compared with 12.05 +/- 4.12 mm, P = 0.0001) and more frequently showed expansive remodeling (56% compared with 14%, P < 0.0001) and calcific plaque (33% compared with 12%, P = 0.01). Multivariable logistic regression analysis identified only insulin resistance (odds ratio, 4.9, P = 0.008) as an independent predictor of expansive remodeling. CONCLUSIONS: Insulin resistance independently predicted expansive remodeling, underscoring the importance of insulin resistance in coronary atheroscrelosis.

Adult↗
PubMed2003

A new dedicated stent and delivery system for the treatment of bifurcation lesions: preliminary experience.

We report the first clinical experience in eight patients with a new stent and delivery system specifically designed for the treatment of bifurcational lesions. The device (AST SLK-View system) consists of a premounted stent and a delivery system. The stent has a side aperture, which orients toward the ostium of the side branch. The system allows deployment of the stent while the access to both main and side branches is maintained by two wires. We evaluated this system in nine bifurcations. The location of bifurcations was left descending artery/diagonal branch in four lesions, left circumflex/obtuse marginal branch in three lesions, and postero-lateral branch/posterior descending artery in two lesions. Predilation was performed in six lesions of the main branches and in five lesions of the side branches. The stent was effectively delivered to all bifurcations except for one, in which the target lesion was located at a distal segment and the device could not be delivered. Following stent implantation in the main branch, two lesions at the side branches were treated by stent, while the other lesions were treated by balloon angioplasty without difficulty. Final kissing balloon was performed in four bifurcation lesions. No adverse event was observed during 1 month of clinical follow-up. Treatment of bifurcation lesions with this new dedicated device appears to be feasible. This new device may introduce a new approach for the treatment of coronary bifurcation lesions.

Aged↗
PubMed2003

Insulin-treated diabetes mellitus and predictors of mid-term clinical outcome after percutaneous coronary interventions with stent implantation.

BACKGROUND: Patients with type II, insulin-dependent diabetes mellitus have a high risk of death and repeat revascularization following successful percutaneous coronary interventions. The predictors of outcome in such patients after coronary stenting have not been clarified. METHODS: We studied 133 consecutive patients with type II, insulin-dependent diabetes mellitus who underwent coronary stenting from November 1992 to May 2001. The clinical outcome and predictors of major adverse cardiac events (MACE; that is death, myocardial infarction, target vessel revascularization) at follow-up were assessed. RESULTS: Out of 133 patients, 102 (76%) had multivessel (> or = 2 vessels) disease. Eight patients (6.0%) had in-hospital MACE. Clinical follow-up data at 19.5 months (range 6.1-100 months) were available for 121 (91%) patients. The MACE rate was 40.5%; 22 patients (18%) died, 17 (14%) of a cardiac death; 7 (5.8%) patients had a myocardial infarction, and target vessel revascularization was performed in 35 (28.9%) patients. At univariate analysis, hypertension (odds ratio-OR 5.5; confidence interval-CI 2.5-12.3; p < 0.001), hypercholesterolemia (OR 3.7; CI 1.7-8.2; p = 0.001), a prior percutaneous coronary intervention (OR 6.6; CI 2.9-15.4; p < 0.001), a prior myocardial infarction (OR 3.1; CI 1.5-6.7; p = 0.003) and the stent length (> or = 15 mm) (OR 2.7; CI 1.5-4.3; p = 0.008) were related to MACE. At multivariate analysis, hypertension (OR 4.1; CI 1.7-9.9; p = 0.002), a prior percutaneous coronary intervention (OR 4.8; CI 1.9-12; p = 0.001) and the stent length (OR 3.0; CI 1.3-7.4; p = 0.01) remained as independent predictors of MACE. CONCLUSIONS: Patients with insulin-dependent diabetes mellitus continue to face a high mortality and incidence of adverse events after stenting. The occurrence of events was related to a history including hypertension, percutaneous coronary interventions and to the stent length.

Aged↗
PubMed2002

Results and long-term predictors of adverse clinical events after elective percutaneous interventions on unprotected left main coronary artery.

BACKGROUND: The safety and efficacy of percutaneous coronary intervention of de novo lesions in unprotected left main coronary arteries remains an unresolved issue. METHODS AND RESULTS: We analyzed 67 consecutive patients treated with the following devices: 39 with stents, 12 with rotational atherectomy plus stents, 13 with directional coronary atherectomy plus stents (a total of 64 patients were treated with stents), and 3 patients with directional coronary atherectomy only. The reference vessel size was 3.78+/-0.73 mm and lesion length was 6.6+/-3.0 mm. In-hospital complications were 2 coronary artery bypass grafts (CABGs) (3.0%), 2 Q-wave myocardial infarctions (MIs) (3.0%), and 3 non-Q-wave MIs (4.5%); there were no deaths. The estimated cardiac survival at 3 years was 91%. The cardiac mortality rate was higher in patients with Parsonnet score >15 versus < or =15 (21.4% versus 4.2%, P=0.02) at 3 years. The independent covariate of cardiac death was preserved left ventricular ejection fraction; for combined cardiac events (cardiac death, MI, repeat revascularization) it was large reference vessel size. Follow-up angiography at 5+/-2 months in 85% of eligible patients revealed 31.4% restenosis. Extending the follow-up to 31+/-23 months (19 patients with follow-up beyond 3 years) the cumulative event rates were 11 deaths (16.4%), 8 of them cardiac (11.9%), 2 (3.0%) MI, and 16 (23.9%) repeat revascularizations (CABG in 5 patients). CONCLUSIONS: Elective percutaneous coronary intervention of de novo lesions in left main coronary arteries is feasible, with low procedural risk. The long-term follow-up revealed a high rate of angiographic restenosis and repeat revascularization, with a relatively high incidence of cardiac death. Reference vessel size and left ventricular function are the most important predictors of favorable follow-up.

Adult↗
PubMed2002

First clinical experience with a paclitaxel derivate-eluting polymer stent system implantation for in-stent restenosis: immediate and long-term clinical and angiographic outcome.

BACKGROUND: It has been shown that antiproliferative drugs such as paclitaxel lower the amount of intimal hyperplasia after stent implantation. We report the first clinical experience of 7-hexanoyltaxol (QP2)-eluting polymer stent system (QuaDS) implantation for in-stent restenosis. METHODS AND RESULTS: Fifteen consecutive patients with elective indication to percutaneous coronary intervention for in-stent restenosis were treated with the QuaDS-QP2 stent implantation. The QuaDS-QP2 stent was successfully implanted in all but 2 target lesions. In one lesion, the restenotic segment could not be completely covered by the stent, and in another lesion, a bare metal stent was implanted distally to the QuaDS-QP2 stent. One patient suffered from postprocedural non-Q-wave myocardial infarction (NQWMI). No other adverse events were observed during hospital stay. Six- and 12-month angiographic and clinical follow-up was scheduled for all patients. At 6 months, 3 patients had target lesion revascularization (20%). Two patients had restenosis (13.3%); one experienced restenosis in a gap between 2 drug-eluting stents, and the other had stent occlusion leading to NQWMI. Minimal intimal hyperplasia was observed in all the segments covered by drug-eluting stents (late loss=0.47+/-1.01 mm with a loss index=0.17+/-0.39). At 12 months, 1 patient suffered from NQWMI, and 8 of 13 patients (61.5%) had angiographic restenosis (late loss=1.36+/-0.94 mm with a loss index=0.62+/-0.44). CONCLUSION: This first experience with QuaDS-QP2 stent implantation for in-stent restenosis revealed minimal intimal hyperplasia at the 6-month follow-up. However, the antiproliferative effect was not maintained at the 12-month follow-up, resulting in delayed occurrence of angiographic restenosis.

Bridged-Ring Compounds↗
PubMed2002

Polytetrafluoroethylene-covered stent and coronary artery aneurysms.

Angiographically detected coronary aneurysms (i.e., coronary segment greater then 1.5 times the normal artery) have an incidence of 0.3%-4.9% among patients undergoing coronary angiography and have been reported after an intervention procedure with a frequency of 2%-10%. The indication for treatment and the best modality still need to be defined. Some authors reported the successful treatment of coronary aneurysms with the polytetrafluoroethylene (PTFE)-covered stent implantation, supporting the role of this strategy. In our institution, from September 1997 to December 1999 eight PTFE-covered stents were implanted to treat seven coronary aneurysms in seven patients. All aneurysms were successfully treated by the PTFE-covered stent. In one case, there was the necessity of an additional PTFE stent to cover the aneurysm completely. In no case did the loss of stent occur. No in-hospital MACE occurred. At 35 +/- 8 (21-44) months, six patients were symptom-free. Angiographic follow-up was performed in all patients at 10 +/- 6 months. Restenosis occurred in one patient (14%) who had repeat percutaneous coronary interventions. This preliminary experience suggests that PTFE-covered stent may be useful in the treatment of coronary artery aneurysms.

Adult↗
PubMed2002

Directional atherectomy of a calcified lesion using a new atherectomy device.

We report on a case of directional atherectomy performed on a calcified coronary lesion using a novel device with a hardened titanium cutter. The successful removal of calcified plaque was documented by intravascular ultrasound assessment and confirmed by histopathological analysis of the obtained plaque specimen.

Atherectomy, Coronary↗
PubMed2002

Effective plaque removal with a new 8 French-compatible atherectomy catheter.

The purpose of this study was to evaluate the safety and efficacy of the new 8 Fr guide catheter-compatible Flexicut directional atherectomy device and to compare it with the conventional Atherocath GTO catheter. The 6 Fr Flexicut catheter has a larger cutting window and a titanium nitride-coated cutter to effect more tissue removal as well as treat mildly calcified lesions. A group of 143 lesions in 117 consecutive patients treated with the Flexicut catheter in four centers were compared with a control group of 277 lesions in 212 consecutive patients treated with the GTO device. Postatherectomy luminal diameters were larger (2.92 +/- 0.79 vs. 2.52 +/- 0.64 mm; P < 0.0001), with more luminal gain (relative gain: 0.58 +/- 0.24 vs. 0.48 +/- 0.25; P = 0.0007) using fewer directional coronary atherectomy (DCA) cuts (12 +/- 7 vs. 16 +/- 9; P = 0.0001) in the Flexicut group. A residual diameter stenosis < 20% immediately after DCA was obtained in 77% of the lesions in the Flexicut group vs. 45% in the GTO group (P < 0.0001). Histology in the former group revealed large calcium speckles in the retrieved specimens. In the Flexicut group, there was a lower incidence of access site complications and damage to the coronary ostium (2.5% vs. 7.5%; P = 0.08). The new Flexicut catheter is more effective than the conventional GTO catheter with a trend for reduced guiding catheter-related complications.

Atherectomy, Coronary↗
PubMed2002

Sirolimus-eluting stents: a review of experimental and clinical findings.

Sirolimus (rapamycin), a macrolide antibiotic with known potent immunosuppressive properties, acts in the first phase (G1) of the cell cycle, blocking its further progression to the phase of DNA synthesis (S). In experimental models, rapamycin is effective in inhibiting smooth muscle cell proliferation and migration after vessel wall injury with balloon angioplasty. These results lead to the clinical application of sirolimus-eluting stents in 45 patients in Sao Paulo and Rotterdam (FIM Registry) and 238 patients in a randomized, European multicenter trial (RAVEL). These trials showed, by angiography and intravascular ultrasound, almost complete abolition of in-stent late hyperplasia up to one year after the procedure. In this review, we describe the experimental and clinical results of sirolimus-eluting stents including our experience of 26 stents implanted in 17 patients. In elective de novo lesions has shown remarkably clear lumens at follow-up angiography and intravascular ultrasound within the stented segments were observed with no lesion progression at the stent margins or thrombosis after a 2 month regimen of aspirin, and ticlopodine or clopidogrel. New large-scale ongoing clinical trials will investigate the efficacy of sirolimus-eluting stents in lesions that are traditionally associated with high restenosis rates after stent implantation, such as long lesions, bifurcations and instent restenosis.

Angina Pectoris↗
PubMed2001

Provisional stenting in small vessels.

Based on the currently available data, the strategy of routine stent placement in unselected lesions located in small coronary arteries provides good immediate results but is still associated with a high incidence of in-stent restenosis. Randomized trials comparing elective stenting with balloon angioplasty have not provided the demonstration that routine stenting is the best strategy for percutaneous intervention in coronary arteries with a reference diameter smaller than 2.75-3.0 mm. This paper describes the rationale for provisional stenting in this clinical setting and reviews the role of quantitative coronary angiography, intracoronary ultrasound and intracoronary Doppler measurements in the identification of lesions that would benefit from adjunctive stent placement after balloon angioplasty and in guiding stent implantation.

Journal Article↗