Home About us Contact
|
Home About us Contact | ||
|
|
||
Native Vessels (native + vessel)
Selected AbstractsThe Use of Intraoperative Doppler Assessment to Guide the Surgical Treatment of Anomalous Right Coronary ArteriesJOURNAL OF CARDIAC SURGERY, Issue 5 2008Louis H. Stein M.H.S. Because of this risk, many patients elect surgical correction of this anomaly. Surgical strategies for correction of this include ostioplasty, coronary artery reimplantation, and, more commonly, coronary artery bypass grafting. After coronary artery bypass grafting, some advocate ligation of the proximal RCA, speculating that competitive flow will cause graft failure. As no objective criteria for this have been established, we propose a method using of intraoperative Doppler flow measurements to guide the decision to preserve the proximal anomalous native vessel. We present three cases in which an RCA with an anomalous origin from the left sinus was corrected with coronary artery bypass grafting with the assistance of intraoperative Doppler flow measurements to guide the decision to preserve the proximal anomalous native vessel. In each case, the RCA was bypassed using a saphenous vein graft (SVG) that was used to bypass origin of the RCA. Flow through the graft was compared with and without ligation of the proximal RCA, before creation of the proximal anastomosis. In each case, flow through the SVG was not significantly reduced with the proximal RCA patent and ligation was not performed. [source] Real-world bare metal stenting: Identification of patients at low or very low risk of 9-month coronary revascularizationCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2004Stephen G. Ellis MD Abstract The high cost of drug-eluting stents (DESs) has made identification of patients who are at low risk for subsequent revascularization after treatment with bare metal stents (BMSs) highly desirable. Previous reports from randomized trials suffer from biases induced by restricted entry criteria and protocol-mandated angiographic follow-up. Between 1994 and 2001, 5,239 consecutive BMS patients, excluding those with coil stents, technical failure, brachytherapy, staged procedure, or stent thrombosis within 30 days, were prospectively identified from a large single-center tertiary-referral-center prospective registry for long-term follow-up. We sought to identify characteristics of patients with very low (, 4%) or low (4,10%) likelihood of coronary revascularization 9 months after BMS. Nine-month clinical follow-up was obtained in 98.2% of patients. Coronary revascularization was required in 13.4% and did not differ significantly by stent type. On the basis of multivariate analysis identifying 11 independent correlates and previous reports, 20 potential low-risk patient and lesion groups (228 ± 356 patients/groups) were identified (e.g, patients with all of the following: native vessel, de novo, reference diameter , 3.5 mm, lesion length < 5 mm, no diabetes, not ostial in location). Actual and model-based outcomes were analyzed. No group had both predicted and observed 9-month revascularization , 4% (very low risk). Conversely, 19 of 20 groups had a predicted and observed revascularization rate of 4,10% (low risk). In the real-world setting, the need for intermediate-term revascularization after BMS may be lower than expected, but it may be very difficult to identify patients at very low risk. Conversely, if the benefits of DESs are attenuated in routine practice, many groups of patients treated with BMSs may have nearly comparable results. Catheter Cardiovasc Interv 2004;63:135,140. © 2004 Wiley-Liss, Inc. [source] Initial clinical experience with distal protection using the FilterWire in patients undergoing coronary artery and saphenous vein graft percutaneous interventionCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2002Jeffrey J. Popma MD Abstract Percutaneous coronary intervention (PCI) of saphenous vein grafts (SVG) and native coronary arteries may be associated with embolization of particulate debris into the distal microcirculation. The FilterWire uses a polyurethane filter bag contained on a radiopaque loop to trap embolic debris during native vessel and SVG intervention. The objectives of this study were to assess the feasibility and safety of the FilterWire during PCI and to examine the size and content of the particulate debris captured during SVG and native vessel intervention. Early angiographic, in-hospital, and 30-day clinical outcomes were reviewed in 35 patients with 36 lesions treated with the FilterWire during PCI. Lesions were located in 22 (61%) native coronary arteries and in 14 (39%) SVGs. Multivessel coronary artery disease was present in 75% of patients. Lesions were complex (ACC/AHA complexity B2 or C) in 81% of cases. The FilterWire was successfully delivered and deployed distal to the site of coronary intervention in 92% of lesions, including 95% of native vessels and 82% of SVG lesions. Embolic debris was entrapped in 82% of these cases. The average particulate debris had a mean major axis of 490 ,m (range, 45,3,302 ,m) and minor axis of 226 ,m (range, 33,1,677 ,m). Although reduced flow was common (36.1%) when the FilterWire was in place, there were no sustained episodes of abrupt closure and only one (2.8%) patient developed sustained no-reflow after FilterWire removal. Distal branch vessel embolization was found in four (11.1%) cases. Major adverse cardiac events occurred in 5 (14%) of 35 patients treated with the device, although 2 of these patients were evolving an acute myocardial infarction at the time of the procedure; in patients meeting the prospectively defined inclusion criteria, the major adverse cardiac event was 6%. These results suggest that the FilterWire is a feasible and safe method of collecting particulate debris released during SVG and native vessel coronary intervention. Its benefit over conventional therapy and other distal protection devices is currently under study. Cathet Cardiovasc Intervent 2002;57:125,134. © 2002 Wiley-Liss, Inc. [source] Electrospun polylactide/silk fibroin,gelatin composite tubular scaffolds for small-diameter tissue engineering blood vesselsJOURNAL OF APPLIED POLYMER SCIENCE, Issue 4 2009Shudong Wang Abstract Many synthetic scaffolds have been used as vascular substitutes for clinical use. However, many of these scaffolds may not show suitable properties when they are exposed to physiologic vascular environments, and they may fail eventually because of some unexpected conditions. Electrospinning technology offers the potential for controlling the composition, structure, and mechanical properties of scaffolds. In this study, a tubular scaffold (inner diameter = 4.5 mm) composed of a polylactide (PLA) fiber outside layer and a silk fibroin (SF),gelatin fiber inner layer (PLA/SF,gelatin) was fabricated by electrospinning. The morphological, biomechanical, and biological properties of the composite scaffold were examined. The PLA/SF,gelatin composite tubular scaffold possessed a porous structure; the porosity of the scaffold reached 82 ± 2%. The composite scaffold achieved the appropriate breaking strength (1.28 ± 0.21 MPa) and adequate pliability (elasticity up to 41.11 ± 2.17% strain) and possessed a fine suture retention strength (1.07 ± 0.07 N). The burst pressure of the composite scaffold was 111.4 ± 2.6 kPa, which was much higher than the native vessels. A mitochondrial metabolic assay and scanning electron microscopy observations indicated that both 3T3 mouse fibroblasts and human umbilical vein endothelial cells grew and proliferated well on the composite scaffold in vitro after they were cultured for some days. The PLA/SF,gelatin composite tubular scaffolds presented appropriate characteristics to be considered as candidate scaffolds for blood vessel tissue engineering. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 [source] Direct Coronary Stenting in Noncomplex and Noncalcified Lesions: Immediate and Mid-term Results of a Prospective RegistryJOURNAL OF INTERVENTIONAL CARDIOLOGY, Issue 4 2000MARC BEDOSSA M.D. Stenting of coronary arteries is currently used in clinical practice. The aim of this prospective registry was to assess the feasibility and the safety of stent implantation without balloon predilatation in noncomplex and noncalcifed lesions. One hundred six stents were implanted in 85 patients who underwent percutaneous coronary angioplasty (PTCA) of native vessels (n = 95) or bypass grafts (n = 11). The lesions were type A (21%) or B1 (79%). The stent was a tubular or a coil stent in 71 ± and 29% of the cases, respectively. The angiographic success rate was 94%. The maximal pressure was 12.1 ± 2.1 atm. In only 7 cases, it was not possible to cross the stenosis with the stent, necessitating retrieval of it and predilation with a balloon before stent implantation. Three dissections after stent implantation were treated by a second stent implantation. The primary success rate was 98% (no acute closure or myocardial infarction). A clinical follow-up was obtained in 98% of patients with a mean delay of 6 ± 0.5 months. Eighty-one percent of patients were asymptomatic. The target lesion revascularization rate was 9.4%. Four patients underwent a new PTCA and four patients a coronary artery bypass graft surgery. This technique of stent implantation appears to be safe with good immediate and midterm results. A prospective randomized trial comparing this technique to the standard technique of stent delivery in noncomplex lesions is currently ongoing with an intravascular ultrasound substudy. [source] Design of Fibrin Matrix Composition to Enhance Endothelial Cell Growth and Extracellular Matrix Deposition for In Vitro Tissue EngineeringARTIFICIAL ORGANS, Issue 1 2009Divya Pankajakshan Abstract Tissue-engineered blood vessel substitutes should closely resemble native vessels in terms of structure, composition, mechanical properties, and function. Successful cardiovascular tissue engineering requires optimization of in vitro culture environment that would produce functional constructs. The extracellular matrix (ECM) protein elastin plays an essential role in the cardiovascular system to render elasticity to blood vessel wall, whereas collagen is responsible for providing mechanical strength. The objective of this study was to understand the significance of various ECM components on endothelial cell (EC) growth and tissue generation. We demonstrate that, even though fibrin is a good matrix for EC growth, fibronectin is the crucial component of the fibrin matrix that enhances EC adhesion, spreading, and proliferation. Vascular EC growth factor is known to influence in vitro growth of EC, but, so far, ECM deposition in in vitro culture has not been reported. In this study, it is shown that incorporation of a mixture of hypothalamus-derived angiogenic growth factors with fibrin matrix enhances synthesis and deposition of insoluble elastin and collagen in the matrix, within 10 days of in vitro culture. The results suggest that a carefully engineered fibrin composite matrix may support EC growth, survival, and remodeling of ECM in vitro and impart optimum properties to the construct for resisting the shear stress at the time of implantation. [source] Windows of operation for bioreactor design for the controlled formation of tissue-engineered arteriesBIOTECHNOLOGY PROGRESS, Issue 3 2009Spyridon Gerontas Abstract The availability of large numbers of units of artificial arteries would offer significant benefits to the clinical management of bypass surgery. Tissue engineering offers the potential of providing vessels that can mimic the morphology, function, and physiological environment of native vessels. Ideally this would involve culturing stem cells in vitro within a biodegradable tubular scaffold so as to construct tissue for implantation. Essential to establishing a robust process for the production of tissue-engineered arteries is the understanding of the impact of changes in the operating conditions and bioreactor design on the construct formation. In this article, models of transport phenomena were developed to predict the critical flow rates and mass transfer requirements of a prototype bioreactor for the formation of tissue-engineered arteries. The impact of the cell concentration, tube geometry, oxygen effective diffusivity in alginate, substrate and metabolite concentration levels, feed rate, and recycle rate on the design of the bioreactor was visualized using windows of operation and contour plots. The result of this analysis determined the best configuration of the bioreactor that meets the cellular transport requirements as well as being reliable in performance while seeking to reduce the amount of nutrients to be used. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] Incomplete cellular depopulation may explain the high failure rate of bovine ureteric graftsBRITISH JOURNAL OF SURGERY (NOW INCLUDES EUROPEAN JOURNAL OF SURGERY), Issue 5 2008J. I. Spark Background: The aim was to assess the results of a decellularized bovine ureter graft (SynerGraft®) for complex venous access. Methods: Bovine ureter conduits were implanted in patients with a failed fistula or access graft in whom native vessels were unsuitable as conduits. Graft histories were obtained from all patients who had undergone this procedure at one institution. Failed grafts were explanted and subjected to histological examination. A sample of fresh bovine ureter was immunostained for galactose (,1 , 3) galactose (,-Gal). Results: Nine patients with a median age of 46 (range 25,70) years underwent complex venous access surgery between August 2004 and November 2006 using a SynerGraft®. Graft types included loop superficial femoral artery to stump of long saphenous vein (four patients), loop brachial artery to vein (two), brachial artery to axillary vein (two) and left axillary artery to innominate vein (one). Three grafts developed aneurysmal dilatation and two thrombosed. Histological assessment of the explanted bovine ureters revealed acute and chronic transmural inflammation. Immunostaining of fresh bovine ureter suggested residual cells and the xenoantigen ,-Gal. Conclusion: Graft failure with aneurysmal dilatation and thrombosis in complex arteriovenous conduits using bovine ureter may be due to residual xenoantigens. Copyright © 2008 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. [source] Randomized evaluation of two drug-eluting stents with identical metallic platform and biodegradable polymer but different agents (paclitaxel or sirolimus) compared against bare stents: 1-Year results of the PAINT trial,CATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 5 2009Pedro A. Lemos MD Abstract Objectives: We tested two novel drug-eluting stents (DES), covered with a biodegradable-polymer carrier and releasing paclitaxel or sirolimus, which were compared against a bare metal stent (primary objective). The DES differed by the drug, but were identical otherwise, allowing to compare the anti-restenosis effects of sirolimus versus paclitaxel (secondary objective). Background: The efficacy of novel DES with biodegradable polymers should be tested in the context of randomized trials, even when using drugs known to be effective, such as sirolimus and paclitaxel. Methods: Overall, 274 patients with de novo coronary lesions in native vessels scheduled for stent implantation were randomly assigned (2:2:1 ratio) for the paclitaxel (n = 111), sirolimus (n = 106), or bare metal stent (n = 57) groups. Angiographic follow-up was obtained at 9 months and major cardiac adverse events up to 12 months. Results: Both paclitaxel and sirolimus stents reduced the 9-month in-stent late loss (0.54,0.44 mm, 0.32,0.43 mm, vs. 0.90,0.45 mm respectively), and 1-year risk of target vessel revascularization and combined major adverse cardiac events (P < 0.05 for both, in all comparisons), compared with controls. Sirolimus stents had lower late loss than paclitaxel stents (P < 0.01), but similar 1-year clinical outcomes. There were no differences in the risk of death, infarction, or stent thrombosis among the study groups. Conclusion: Both novel DES were effective in reducing neointimal hyperplasia and 1-year re-intervention, compared to bare metal stents. Our findings also suggest that sirolimus is more effective than paclitaxel in reducing angiographic neointima, although this effect was not associated with better clinical outcomes.© 2009 Wiley-Liss, Inc. [source] Initial clinical experience with distal protection using the FilterWire in patients undergoing coronary artery and saphenous vein graft percutaneous interventionCATHETERIZATION AND CARDIOVASCULAR INTERVENTIONS, Issue 2 2002Jeffrey J. Popma MD Abstract Percutaneous coronary intervention (PCI) of saphenous vein grafts (SVG) and native coronary arteries may be associated with embolization of particulate debris into the distal microcirculation. The FilterWire uses a polyurethane filter bag contained on a radiopaque loop to trap embolic debris during native vessel and SVG intervention. The objectives of this study were to assess the feasibility and safety of the FilterWire during PCI and to examine the size and content of the particulate debris captured during SVG and native vessel intervention. Early angiographic, in-hospital, and 30-day clinical outcomes were reviewed in 35 patients with 36 lesions treated with the FilterWire during PCI. Lesions were located in 22 (61%) native coronary arteries and in 14 (39%) SVGs. Multivessel coronary artery disease was present in 75% of patients. Lesions were complex (ACC/AHA complexity B2 or C) in 81% of cases. The FilterWire was successfully delivered and deployed distal to the site of coronary intervention in 92% of lesions, including 95% of native vessels and 82% of SVG lesions. Embolic debris was entrapped in 82% of these cases. The average particulate debris had a mean major axis of 490 ,m (range, 45,3,302 ,m) and minor axis of 226 ,m (range, 33,1,677 ,m). Although reduced flow was common (36.1%) when the FilterWire was in place, there were no sustained episodes of abrupt closure and only one (2.8%) patient developed sustained no-reflow after FilterWire removal. Distal branch vessel embolization was found in four (11.1%) cases. Major adverse cardiac events occurred in 5 (14%) of 35 patients treated with the device, although 2 of these patients were evolving an acute myocardial infarction at the time of the procedure; in patients meeting the prospectively defined inclusion criteria, the major adverse cardiac event was 6%. These results suggest that the FilterWire is a feasible and safe method of collecting particulate debris released during SVG and native vessel coronary intervention. Its benefit over conventional therapy and other distal protection devices is currently under study. Cathet Cardiovasc Intervent 2002;57:125,134. © 2002 Wiley-Liss, Inc. [source] | ||||||||||