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At least 937 records · Page 52Linked to original sources
PubMed1998

Revision of failing lower extremity bypass grafts.

BACKGROUND: Color-duplex ultrasound (CDU) surveillance of arterial bypass grafts has been validated, but the natural history of "failing" grafts remains poorly defined. Our purpose was to compare failing grafts having prophylactic revision with those that did not. METHODS: Postoperative duplex surveillance was performed in an accredited vascular laboratory for all lower extremity bypass grafts performed at a single institution. Eighty-five infrainguinal grafts (57 vein, 21 polytetrafluoroethylene (PTFE), and 7 composite grafts) in 83 patients were identified as failing by accepted criteria. Twenty-five grafts were revised early (early), 20 grafts revised more than 2 months after the initial CDU-abnormality (late), and 40 grafts were not prophylactically revised (no revision) at any time. RESULTS: The three groups were not different (P > 0.10) with regard to gender, age, level of bypass, type of conduit, location of stenoses, or timing of abnormality after surgery. No revision patients more frequently had diffuse low peak systolic flow velocity (PSV) as the CDU abnormality (P = 0.013). Cumulative primary patency was significantly better at 12 months (P = 0.028) in the no revision group (78.9%) compared with early grafts (43.1%) or late grafts (63.8%), and this difference remained significant when low PSV grafts were excluded from analysis. However, assisted primary patency, secondary patency, and limb salvage rates did not differ between the three groups (P > 0.10). CONCLUSIONS: Our experience in this retrospective study contradicts other reports supporting the efficacy of prophylactic graft revision for grafts identified as failing by currently accepted CDU criteria. Refinement of CDU criteria to more accurately predict graft thrombosis is needed.

Adult↗
PubMed2004

Factors influencing the results of double-valve surgery in patients with fulminant endocarditis: the importance of valve selection.

BACKGROUND: Extension of infection below the aortic valve is a serious complication, especially with mitral valve involvement. Mortality is substantial and reinfection can strongly influence outcome. PATIENTS: Of 327 surgical patients with active infective aortic valve endocarditis admitted to the Deutsches Herzzentrum Berlin for surgical treatment between December 1996 and December 2003, 108 had root abscess, and 53 (25.5%) had diagnoses of secondary infective mitral valve disease (SMVD). The mean age (+/-SD) was 53 +/- 14.2 years; there were 37 men and 16 women. METHODS: The secondary lesion on the mitral valve was classified as SMVD requiring double-valve surgery (DVS). This prospective clinical and echocardiographic study revealed 2 paths of infection extension into the mitral valve. In the DVS group, 38 patients (71.7%) had tissue metastatic lesions, and 15 patients (28.3%) had a jet lesion on the mitral valve. Most patients (42) with SMVD had an aortic ring abscess as the primary lesion. RESULTS: All patients with destructive endocarditic doublevalve disease received aortic and mitral valve surgery. In 19 cases (35.8%), mitral valve reconstruction was undertaken; in 4 cases, mitral valve replacement had to be carried out after attempted mitral valve reconstruction. Concomitant mitral valve replacement because of severe damage to the valvular and subvalvular apparatus was performed in 30 patients (56.6%). Other types of surgery performed in 11 cases (20.8%) were 8 closures of a septic ventricular septal defect and 3 closures of a fistula to the right ventricle or right atrium. Twenty-seven patients were treated with a Shelhigh prosthesis, 18 were treated with double-valve replacement (both Shelhigh), and 9 were treated with an aortic Shelhigh prosthesis and concomitant mitral valve reconstruction. Homografts were used in 17 patients, with mitral valve reconstruction carried out in 10 patients and a stented mitral prosthesis in 7. In 9 cases, 2 stented valve prostheses were used. There were 14 early (60 days) deaths (26.4%). Septic shock, severe annular and subannular destruction, and poor left ventricular function (end-diastolic dimension >65 mm, ejection fraction <40%) were the significant risk factors determined in the multivariate analysis. Function of Implants: Continuous and Color Doppler Investigation: Comparative studies of 2 different implants in the aortic position were performed late postoperatively (325 +/- 251 days) for homografts and the Shelhigh stentless prosthesis. The calculated instantaneous (maximal Doppler) gradient and the mean pressure gradient through the aortic implants were 19 +/- 10.4 mm Hg and 12 +/- 5.7 mm Hg, respectively, for the homografts and 24 +/- 8.4 mm Hg and 15 +/- 4.6 mm Hg, respectively, for the Shelhigh stentless prosthesis (not significantly different for the 2 groups). There was no mitral or aortic valve dysfunction. A trivial paravalvular leakage in the mitral position in 1 patient and a pseudoaneurysm of the left ventricular out- flow tract without leakage or valvular dysfunction in another were diagnosed by postoperative Doppler investigation. CONCLUSIONS: The mortality in patients with destructive endocarditis requiring DVS depends mostly on the patients' preoperative hemodynamic situation. The risk of reinfection can be minimized if valve substitutes are properly selected (homografts, Shelhigh No-React SuperStentless and No-React BioConduit in the aortic position, or Shelhigh BioMitral in the mitral position). Concomitant mitral valve reconstruction procedures do not increase the risk of mitral reinfection.

Endocarditis↗
PubMed1995

Polyvinylidene fluoride (PVDF) as a biomaterial: from polymeric raw material to monofilament vascular suture.

This study identified the effects of various manufacturing processes on the crystalline microstructure, mechanical properties, and biocompatibility of a polyvinylidene fluoride (PVDF) suture. To achieve this, changes in the crystalline microstructure and the tensile behavior of PVDF monofilaments were monitored in vitro after different thermal processing, coloration, and sterilization treatments. In addition, the in vivo biocompatibility of the manufactured and sterilized PVDF suture was assessed by using it to anastomose a preclotted polyester vascular prosthesis as a thoracoabdominal bypass in a series of dogs. The tissue response was followed by histologic and scanning electron microscopy over implantation periods ranging from 4 h to 6 months. Differential scanning calorimetry and infrared spectroscopy (FTIR-ATR) showed that thermal processing and the addition of a coloring agent had a direct effect on modifying the crystalline microstructure and hence changing the mechanical properties. For example, thermal processing converted some of the alpha phase into the beta and gamma polymorphs, whereas coloration led only to a major increase in the beta-to-alpha ratio. The tensile properties were found to be optimized when the relative proportion of the beta and gamma phases combined compared to the alpha form gave rise to an FTIR A509/A532 absorption ratio between 4.0 and 4.5. Sterilization was found to cause some modifications to the crystalline microstructure near the surface of the monofilaments, but it did not change their mechanical properties. Pathologic examination of the anastomotic regions after different periods of implantation revealed a minimal cellular response, with no mineralization, intimal hyperplasia, or excessive fibrous tissue reaction. This good biocompatibility, together with other desirable characteristics such as ease of manipulation and satisfactory mechanical strength, makes PVDF an attractive alternative monofilament suture material for cardiovascular surgery.

Animals↗
PubMed2005

Congenital superior vena cava obstruction causing anasarca and respiratory failure in a newborn: successful transcatheter therapy.

Superior vena cava (SVC) obstruction is a rare entity in the pediatric population. It usually presents in association with either previous cardiac surgery or external compression from a neoplasm. We present the case of an infant born with congenital SVC obstruction and significant bilateral chylothorax and anasarca necessitating mechanical ventilation. Successful placement of an intravascular stent led to resolution of the chylothoraces with rapid clinical improvement.

Angioplasty, Balloon↗
PubMed2001

Three-dimensional planning and simulation of hip operations and computer-assisted construction of endoprostheses in bone tumor surgery.

OBJECTIVE: This article presents the VIRTOPS (VIRTual Operation Planning in Orthopaedic Surgery) software system for virtual preoperative planning and simulation of hip operations. The system is applied to simulate the endoprosthetic reconstruction of the hip joint with hemipelvic replacement, and supports the individual design of anatomically adaptable, modular prostheses in bone tumor surgery. The virtual planning of the operation and the construction of the individual implant are supported by virtual reality techniques. The central step of the operation planning procedure, the placement of the cutting plane in the hip bone, depends strongly on the tumor's position. Segmentation of the tumor and the bones in MR and CT data, as well as fusion of MR and CT image sequences, is necessary to visualize the tumor's position within the hip bone. MATERIALS AND METHODS: Three-dimensional models of the patient's hip are generated based on CT image data. A ROI-based segmentation algorithm enables the separation of the bone tumor in multispectral MR image sequences. A special registration method using segmentation results has been developed to transfer CT and MR data into one common coordinate system. During the 3D planning process, the surgeon simulates the operation and defines the position and geometry of the custom-made endoprosthesis. Stereoscopic visualization and 3D input devices facilitate navigation and 3D interaction in the virtual environment. Special visualization techniques such as texture mapping, color coding of quantitative parameters, and transparency support the determination of the correct position and geometry of the prosthesis. RESULTS AND CONCLUSIONS: The VIRTOPS system enables the complete virtual planning of hip operations with endoprosthetic reconstruction, as well as the optimal placement and design of endoprostheses. After the registration and segmentation of CT and MR data, 3D visualizations of the tumor within the bone are generated to support the surgeon during the planning procedure. In the virtual planning environment, individually adapted endoprostheses can be constructed without the need to generate expensive solid 3D models. Furthermore, different operation strategies can be compared easily. Three-dimensional images and digital movies generated during the virtual operation planning can be used for case documentation and patient information purposes.

Algorithms↗
PubMed1992

Geometrically accurate transaortic mapping of left ventricular endocardial activation during surgery.

A device was developed for mapping left ventricular endocardial activation through the aortic valve during surgery. It uses an exploring electrode at the tip of a hand-held probe that is mounted on a mechanical arm with six joints whose movements are digitized by a computer while the position of the probe tip is calculated continuously. The probe is inserted by the surgeon into the left ventricle retrogradely through the aortic valve after the patient is on total cardiopulmonary bypass, the aorta has been opened and the coronary arteries cannulated. The electrode position relative to the aortic valve and left ventricular apex is displayed continuously on a computer screen. When electrograms are recorded from the probe, their positions are displayed on the screen relative to a stylized grid of the left ventricular endocardial surface and are color-coded to indicate the activation sequence. In a patient with nonischemic ventricular tachycardia, the arrhythmia was successfully mapped and cryoablated with use of the device. The device will be developed so that a cryoprobe can be substituted for the exploring electrode and positioned at the source of activation determined by the map.

Adult↗
PubMed1999

Clinical evaluation of all-ceramic crowns (Dicor) in general practice.

STATEMENT OF PROBLEM: There are few studies regarding all-ceramic full crowns placed by general practitioners; however, most dental restorations are carried out by general practitioners, and their clinical performance may be of particular interest. PURPOSE: Ninety-eight all-ceramic Dicor crowns placed in 46 patients regularly visiting a general practice were evaluated with the California Dental Association's (CDA) criteria. Mean and median ages of the crowns were 6.1 and 5.8 years, respectively (range 1.4 to 10. 9 years). Crowns were luted with either a glass ionomer, zinc phosphate, or resin composite cement. RESULTS: Of the 98 crowns, 82% were rated satisfactory. For marginal integrity, 51% were rated excellent. Fracture was registered in 14 all crowns, and 1 endodontically treated tooth with a Dicor crown was extracted because of root fracture; of the remaining 83 crowns, 55% were rated excellent for color. Corresponding figures for surface and anatomic form were 46% and 23%, respectively. The most common finding was slightly rough surfaces (64%). No statistically significant difference was observed for fracture rates obtained when the crowns luted with different luting agents were compared (P >.05). There was no more plaque or bleeding on probing (P >.05) in connection with the Dicor crowns than in the control surfaces.

Adult↗
PubMed1999

Black iris-diaphragm intraocular lens for aniridia and aphakia.

We present the first reported use in the United States of a black iris-diaphragm intraocular lens (IOL) for the treatment of traumatic aniridia and aphakic bullous keratopathy. The patient presented to a university-based practice with contact-lens-intolerant aniridia and aphakia with painful bullous keratopathy from a failed corneal graft. He was treated with combined penetrating keratoplasty and transscleral fixation of an aniridia IOL. The patient's preoperative symptoms of debilitating glare and photophobia resolved substantially after surgery, despite mild postoperative inflammation that resolved. The symptoms associated with aniridia can be successfully treated with a black iris-diaphragm IOL; however, chronic low-grade inflammation has been reported with its use in some cases.

Adult↗
PubMed2003

Corneal topography and contact lenses.

Regardless of whether CVK is used qualitatively for RGP lens design selection or quantitatively in RGP parameter selection, it has a significant role in contact lens practice. Further advancements and testing on CVK-based RGP fitting modules and fluorescein simulations will make CVK an invaluable tool for the RGP lens fitter. Soft lens applications of CVK data are already being tested [42,43]. This technology will become the standard of care for all contact lens patients and will most likely replace the keratometer.

Color↗
PubMed2001

Colour stability of a new light-cured ceramic stain system subjected to glazing temperature.

A light-cured ceramic stain system (Orbit LC) offers promise as an effective method for surface characterization of ceramic restorations. This study evaluated colour change after glazing procedures for six commonly used stains from this novel system. One hundred and five ceramic specimens were made of the same enamel porcelain powder and standardized in size. The stains were applied on ceramic blocks and light-cured according to the manufacturer's recommendations. Porcelain colour was then measured with a calibrated colorimeter before and after each glazing procedure. The CIEL*a*b* colour co-ordinates were obtained as a measure of the direction and magnitude of colour change. Colour changes were noted for all six stains when subjected to the first glazing procedure (DeltaE* = 1.25-4.73). Brown, orange and green stains showed the greatest colour shifts (DeltaE* > 3.3), which might be considered clinically significant. However, the colour change is not of the same pattern in the colour space. Compared with the first glazing procedure, the second and third glazing procedures demonstrated less effect on the colour stability of the stains (DeltaE* = 0.36-1.12). The results provide important information about colour shifts in the system, which require overcorrection during stain application.

Analysis of Variance↗
PubMed2001

Topical application of antiangiogenic agent AGM-1470 suppresses anastomotic intimal hyperplasia after ePTFE grafting in a rabbit model.

BACKGROUND: Anastomotic intimal hyperplasia (AIH) remains an unsolved problem. Angiogenesis around the anastomosis is one of the important mechanisms accelerating AIH. In this study, we investigated the effects of an antiangiogenic agent AGM-1470 (O-[chloroacetyl-carbamoyl] fumagillol: AGM) on the thickness of AIH after expanded polytetrafluoroethylene grafting. METHODS: Study 1: Smooth muscle cells (SMCs) were cultured to form 3-mm-side square colonies by using 4 kinds of culture medium, containing AGM at concentrations of 0, 0.1, 1.0, and 10 ng/mL. The SMC colony spreading distance in each group was measured as an index of mitogenic activity. The isolated proliferative activity of SMCs was also assessed. Study 2: Male New Zealand white rabbits underwent inlay expanded polytetrafluoroethylene grafting of the carotid arteries. They were divided in 4 groups (control, vehicle, AGM [0.5], and AGM [5]) in which no topical application, Vaseline ointment, Vaseline ointment containing 0.5 mg AGM, or Vaseline ointment containing 5 mg AGM was applied to the anastomoses, respectively. Rabbits were fed a high-cholesterol diet for 2 weeks before and 8 weeks after the operation. AIH thickness was measured and capillary formation and SMC accumulation around the anastomoses were examined with immunohistochemical staining. RESULTS: Study 1: AGM suppressed SMC migratory activity in a cytostatic, but not cytotoxic, manner. Study 2: AGM ointment inhibited AIH in proportion to its concentration and also suppressed new capillary formation around the anastomoses and SMC accumulation in AIH. CONCLUSIONS: Topical application of the antiangiogenic agent AGM may become an important strategy for preventing AIH.

Angiogenesis Inhibitors↗