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Int J Cardiol

Restenosis following stent implantation diminishes the procedure's efficacy influencing long-term clinical outcomes. Stent-based drug delivery emerged a decade ago as an effective means of reducing neointimal hyperplasia by providing localized pharmacotherapy during the acute phase of the stent-induced injury and the ensuing pathobiological mechanisms. However, drug-eluting stent (DES) restenosis may still occur especially when stents are used in complex anatomical and clinical scenarios. A DES consists of an intravascular metallic frame and carriers which allow controlled release of active pharmaceutical agents; all these components are critical in determining drug distribution locally and thus anti-restenotic efficacy. Furthermore, dynamic flow phenomena characterizing the vascular environment, and shear stress distribution, are greatly influenced by stent implantation and play a significant role in drug deposition and bioavailability within local vascular tissue. In this review, we discuss the performance of DES and the interaction of the different DES components with the hemodynamic milieu emphasizing on the inhibition of clinical restenosis. Pharmacol Ther

Objectives We aimed to explore the relationship of neointimal thickness (NT) to shear stress (SS) after implantation of sirolimus-eluting stents (SES) and paclitaxel-eluting stents (PES) compared with bare-metal stents (BMS). We then tested the hypothesis that drug elution attenuates the SS effect. Background Neointimal thickness after BMS implantation has been associated with SS; pertinent data for drug-eluting stents (DES) are limited. Methods Three-dimensional coronary artery and stent reconstruction was performed in 30 patients at 6-month follow-up after SES (n = 10), PES (n = 10), or BMS (n = 10) implantation. Baseline SS at the stent surface was calculated using computational fluid dynamics and NT at follow-up was computed in 3-dimensional space. Results Neointimal thickness was lower in DES versus BMS (0.03 +/- 0.07 mm vs. 0.16 +/- 0.08 mm, p < 0.001) and maximum NT was reduced in SES versus PES (0.33 +/- 0.13 mm vs. 0.46 +/- 0.13 mm, p = 0.025). In the total population, both SS (slope: -0.05 mm/Pa, p < 0.001) and DES (coefficient for DES vs. BMS: -0.17 mm, p = 0.003) were independent predictors of NT. Subgroup analysis demonstrated a significant negative relationship of NT to SS in PES (slope: -0.05 mm/Pa, p = 0.016) and BMS (slope: -0.05 mm/Pa, p = 0.001). Sirolimus elution significantly attenuated the effect of SS on NT (interaction coefficient for SES vs. BMS: 0.04 mm/Pa, p = 0.023), whereas the SS effect remained unchanged in PES (interaction coefficient for PES vs. BMS: 0.01 mm/Pa, p = 0.71). Conclusions Neointimal thickness is significantly correlated (inversely) to SS in PES as in BMS. Sirolimus elution abrogates the SS effect on the neointimal response following stent implantation, whereas the SS effect is unchanged in PES. (J Am Coll Cardiol Intv 2010;3:1181-9) (C) 2010 by the American College of Cardiology Foundation Jacc-Cardiovascular Interventions

Background: The association of shear stress (SS) with in-stent restenosis after bare metal stenting is not clear. We investigated the significance of SS on predicting areas with neointima thickness (NT) in humans and the effect of vascular brachytherapy (VBT) following coronary artery stenting on the relationship of SS with NT. Methods: By using coronary angiography and intravascular ultrasound, we performed three-dimensional (3D) artery and stent reconstruction in 14 patients at 8-month follow-up after bare metal stenting with (stent&VBT group; 7 patients) or without (stent group; 7 patients) adjunctive beta-VBT. In-stent SS was calculated by applying computational fluid dynamics to the stent reconstruction and NT was determined in 3D space. Results: NT was significantly increased in the stent group (0.2 +/- 0.16 mm vs. 0.07 +/- 0.18 mm, p

In this study we investigated the accuracy of monoplane and biplane quantitative coronary angiography in estimating the luminal dimensions, Using intracoronary Ultrasound as gold standard. Biplane angiography and intracoronary ultrasound were performed in 24 arterial segments. The end-diastolic intracoronary ultrasound Frames Were manually selected and segmented. In 2 end-diastolic X ray projections, quantitative coronary angiography was performed and a novel methodology was applied to register the segmented frames onto the processed angiographic images. The luminal areas determined by quantitative coronary angiography in 1 (monoplane) and 2 projections (mean) were compared with those determined 1)), intracoronary ultrasound. The obtained correlation coefficients for the monoplane and mean estimations were 0.69 +/- 0.12 and 0.77 +/- 0.08, respectively. It would appear that by increasing the angle between the biplane projections, the correlation between intracoronary ultrasound and mean estimations improves. Our results provide evidence that orthogonal biplane angiography is more reliable and should be preferred to assess luminal dimensions. Angiology

Objectives: The development of an automated, user-friendly system (ANGIOCARE), for rapid three-dimensional (3D) coronary reconstruction, integrating angiographic and, intracoronary ultrasound (ICUS) data. Methods: Biplane angiographic and ICUS sequence images are imported into the system where a prevalidated method is used for coronary reconstruction. This incorporates extraction of the catheter path from two end-diastolic X-ray images and detection of regions of interest (lumen, outer vessel wall) in the ICUS sequence by an automated border detection algorithm. The detected borders are placed perpendicular to the catheter path and established algorithms used to estimate their absolute orientation. The resulting 3D object is imported into an advanced visualization module with which the operator can interact, examine plaque distribution (depicted as a color coded map) and assess plaque burden by virtual endoscopy. Results: Data from 19 patients (27 vessels) undergoing biplane angiography and ICUS were examined. The reconstructed vessels were 21.3-80.2 mm long. The mean difference was 0.9 +/- 2.9% between the plaque volumes measured using linear 3D ICUS analysis and the volumes, estimated by taking into account the curvature of the vessel. The time required to reconstruct a luminal narrowing of 25 mm was approximately 10 min. Conclusion: The ANGIOCARE system provides rapid coronary reconstruction allowing the operator accurately to estimate the length of the lesion and determine plaque distribution and volume. (C) 2008 Wiley-Liss, Inc. Catheterization and Cardiovascular Interventions

OBJECTIVES: To determine the impact of the level of kidney function on the extended (>5 years) long-term clinical course of patients undergoing percutaneous coronary intervention (PCI). BACKGROUND: Chronic kidney disease (CKD) has been significantly associated with an increased in-hospital and 1-year mortality following PCI. METHODS: In this single-centre retrospective study, glomerular filtration rate (GFR) at baseline was estimated in 371 patients not on dialysis, who underwent successful PCI between mid-1995 and mid-1999. Baseline demographic and angiographic characteristics, and long-term major adverse cardiac events and symptoms were compared for patients with GFR > or =60 ml/min/1.73 m(2) (normal or mildly impaired renal function) and GFR > or = 60 ml/ min/1.73 m(2) (CKD). The independent effect of GFR, modelled both as a categorical and a continuous variable, on long-term clinical outcomes was also investigated using multivariate Cox regression analysis. RESULTS: Nine-year all-cause and cardiac mortality rates were significantly higher in the CKD group (45.9% vs. 10.6%, P < 0.0001 and 35.4% vs. 7.1%, P < 0.0001 respectively), while there was no difference in the repeat revascularization (P = 0.27) and nonfatal Q-wave myocardial infarction (P = 0.74) rates. Multivariate analysis demonstrated an independent impact of the level of GFR on long-term mortality; adjusted 9-year all-cause and cardiac mortality increased by approximately 16% and 11%, respectively for a decrease of GFR from 120 to 60 ml/min/1.73 m(2) and by approximately 14% and 9%, respectively for a decrease of GFR from 60 to 30 ml/min/1.73 m(2). CONCLUSIONS: The level of renal function is a strong determinant of long-term all-cause and cardiac mortality after successful PCI. Catheter Cardiovasc Interv

We report a patient with coronary dilatation 10 weeks after paclitaxel-eluting stent implantation in the right coronary artery (RCA). Coronary angiography demonstrated a double-locular lumen dilatation in the body of the stented segment of the RCA, and intravascular ultrasound interrogation revealed the corresponding region with evidence of tissue regression behind the stent struts, incomplete stent apposition, and lumen enlargement. After three-dimensionally (3D) reconstructing the RCA, we applied computational fluid dynamics to the 3D RCA model, representing the lumen of the artery at the moment of stent implantation, and investigated the correlation of both neointimal thickness and tissue regression depth with shear stress in the stent. Neointimal thickness was found to be inversely related to shear stress, but there was no significant association of tissue regression depth with shear stress. Post-procedural stent malapposition, thrombus dissolution, and less possibly, a localized hypersensitivity reaction are potential mechanisms for the lumen enlargement in this case. Heart Vessels

We report for the first time a real three-dimensional reconstruction of the left main coronary artery, left main bifurcation, left anterior descending coronary artery and left circumflex coronary artery using biplane angiography and intravascular ultrasound imaging in a patient with a proximal stenosis in the left anterior descending coronary artery. By using computational fluid dynamics in the three-dimensional luminal model we computed endothelial shear stress, while plaque thickness was calculated as the difference between the three-dimensional lumen and outer vessel wall; plaque thickness was found to be inversely related to endothelial shear stress in the left main coronary artery and bifurcation. The application of our methodology for real three-dimensional reconstruction of the left main coronary artery and bifurcation is useful for investigating the relationship of hemodynamic parameters with plaque thickness in this critical coronary region. (c) 2006 Elsevier Ireland Ltd. All rights reserved. Int J Cardiol

Polytetrafluoroethylene-covered stents (PCS) were recently proposed as a new modality mainly for the treatment of saphenous vein graft lesions, but restenosis occurring principally at the edges restricted their clinical use in the management of coronary aneurysms and perforations.Aims: To investigate the safety and effectiveness of the overlapping implantation of drug-eluting stents (DES) with PCS in clinical scenarios where the latter are indicated.Methods: Since April 2002, when DES were introduced in clinical practice, 14 consecutive patients were -treated with overlapping implantation of PCS with DES in 3 centres. Seven patients were treated for coronary aneurysms, 5 for coronary perforations and 2 for branch occlusion. The incidence of any major adverse cardiac events defined as death, myocardial infarction (MI), and target vessel revascularisation (TVR) was retrospectively evaluated. A control angiography was available in 13 patients, and quantitative coronary angiography was performed before and after the intervention and at follow-up to evaluate restenosis rate and late loss.Results: At a mean clinical follow-up of 21.9 months there were no deaths or MI's, while one patient with occlusive restenosis underwent successful TVR (7.7%). At angiographic follow-up (mean: 9.7 months) there was one patient with restenosis (7.7%), who had a total occlusion. After excluding the patient with the occlusive restenosis mean diameter stenosis was 22.4+/-11.7% and late loss was 0.18+/-0.35 mm at follow-up. No early or late stent thrombosis occurred.Conclusion: Overlapping implantation of PCS with DES seems to be a safe and effective therapeutic modality demonstrating a low incidence of clinical and angiographic restenosis. EuroIntervention

The aim of this study is to describe a new method for the three-dimensional reconstruction of coronary arteries and its quantitative validation. Our approach is based on the fusion of the data provided by intravascular ultrasound images (IVUS) and biplane angiographies. A specific segmentation algorithm is used for the detection of the regions of interest in intravascular ultrasound images. A new methodology is also introduced for the accurate extraction of the catheter path. In detail, a cubic B-spline is used for approximating the catheter path in each biplane projection. Each B-spline Curve is Swept along the normal direction of its X-ray angiographic plane forming a surface. The intersection of the two surfaces is a 3D curve, which represents the reconstructed path. The detected regions of interest in the IVUS images are placed perpendicularly onto the path and their relative axial twist is computed using the sequential triangulation algorithm. Then, ail efficient algorithm is applied to estimate the absolute orientation of the first IVUS frame. In order to obtain 3D visualization the commercial package Geomagic Studio 4.0 is used. The performance of the proposed method is assessed using a validation methodology which addresses the separate validation of each step followed for obtaining the coronary reconstruction. The performance of the segmentation algorithm was examined in 80 IVUS images. The reliability of the path extraction method was studied in vitro using a metal wire model and in vivo in a dataset of I I patients. The performance of the sequential triangulation algorithm was tested in two gutter models and in the coronary arteries (marked with metal clips) of six cadaveric sheep hearts. Finally, the accuracy in the estimation of the first IVUS frame absolute orientation was examined ill the same set of cadaveric sheep hearts. The obtained results demonstrate that the proposed reconstruction method is reliable and capable of depicting the morphology of coronary arteries. (C) 2005 Elsevier Ltd. All rights reserved. Computerized Medical Imaging and Graphics

Objectives: This study reports the 9-year clinical outcome of 409 consecutive patients, who underwent coronary angioplasty with provisional stenting during the years 1995 to 1999 in the University Hospital of Northwestern Greece. Background: Despite the rapid changes of interventional cardiology, long-term follow-up studies are useful for identifying its limitations and indicating future changes.Methods: Baseline characteristics and information on survival, major cardiac events and symptoms were retrospectively obtained from medical records or telephone contact. Patient survival rates were calculated and predictive factors for survival and cardiac events were identified. Results: Follow-up information was obtained in 403 patients (98.5%). Three hundred and thirty-one patients (82%) were alive with 150 (45%) being symptom free. The cumulative 5- and 9-year survival rates were 87% and 78% respectively, and the corresponding survival free from major adverse cardiac events was 65% and 55%. Independent factors affecting survival were age>65 years, diabetes, hypertension, multivessel disease and ejection fraction

Hellenic J Cardiol

Objective: To investigate the impact of BiodivYsio dexamethazone-eluting stent versus BiodivYsio stent on the 12-month outcomes after revascularisation of patients with single vessel coronary artery disease.Methods: From March 2003 to February 2004, 102 patients with non-ST elevation acute coronary syndromes, angina or silent ischemia after recent ST elevation myocardial infarction (

Hellenic J Cardiol

Eur Heart J