Polyethylene Terephthalates
Polyethylene
Polyethylenes
Polyethylene Glycols
Prosthesis Failure
Endovascular stent graft repair of aortopulmonary fistula. (1/416)
Two patients who had aortopulmonary fistula of postoperative origin with hemoptysis underwent successful repair by means of an endovascular stent graft procedure. One patient had undergone repeated thoracotomies two times, and the other one time to repair anastomotic aneurysms of the descending aorta after surgery for Takayasu's arteritis. A self-expanding stainless steel stent covered with a Dacron graft was inserted into the lesion through the external iliac or femoral artery. The patients recovered well, with no signs of infection or recurrent hemoptysis 8 months after the procedure. Endovascular stent grafting may be a therapeutic option for treating patients with aortopulmonary fistula. (+info)Carotid endarterectomy outcome with vein or Dacron graft patch angioplasty and internal carotid artery shortening. (2/416)
OBJECTIVE: This analysis of the outcome of carotid endarterectomy (CEA) was performed during a period of transition from the frequent use of autologous greater saphenous vein grafting to the frequent use of Dacron graft patch reconstruction and from the infrequent use to the moderate use of eversion plication shortening of the endarterectomized internal carotid artery segment. METHODS: From 1990 to 1997, 697 consecutive primary CEAs were performed on 326 men (61 bilateral CEAs) and 272 women (38 bilateral CEAs) with a mean age (+/- SD) of 68 +/- 9 years. The indications were transient ischemic attack in 31% of the patients, stroke or reversible ischemic neurologic deficit in 18%, global ischemia in 12%, and asymptomatic stenosis >/=70% in 39%. Patch reconstruction was performed in the 678 CEAs in which the arteriotomy extended distal to the internal carotid artery bulb (97%; 370 saphenous vein grafts, 308 Dacron grafts). Primary closure was used in the other 19 CEAs. Early in this series, saphenous vein patching frequently was performed, with a gradual transition to the frequent use of knitted Dacron grafts. Concurrent with this, the frequency of the shortening of the internal carotid artery increased from 7% to 40%. Postoperative duplex scans were obtained on 619 CEAs (91%). RESULTS: There were four deaths (0.6%) in 30 days-three from myocardial infarction and one from hyperperfusion stroke. Thirteen strokes (1.9%), nine ipsilateral and four contralateral, occurred in 30 days. Four nonfatal strokes and one death occurred in the saphenous vein group (3.2%), and eight strokes and two deaths occurred in the Dacron graft group (1.4%; P =.16). The combined 30-day stroke or death rate was 2.3% (16/697), and the hospital rate was 1.7% (12/697). Of the three internal carotid artery occlusions, two were identified at 2 months (one Dacron graft, one saphenous vein) and one was identified at 1 year (Dacron graft). Nonocclusive (>/=50%) restenosis was identified in 16 CEAs. Fifteen of these were in the internal carotid artery. The cumulative Kaplan-Meier method of life-table analysis for the >/=50% restenosis rate at 2 months, 6 months, 1 year, and 3 years for Dacron graft patched CEA was 1.7%, 2.3%, 8.8%, and 12.3% and for saphenous vein patched CEA was 0.3%, 0.3%, 0.3%, and 1.1% ( P <.0001). At the same time intervals, the >/=50% restenosis rate for internal carotid artery shortening was 1.0%, 2.5%, 13.7%, and 19.5%, and, when shortening was not done, the rate was 0.8%, 0.8%, 1.1%, and 3.1% (P <.0001). The >/=50% restenosis rate at the same intervals for women was 0.8%, 1.3%, 5.2%, and 8.9%, and, for men, the rate was 0.9%, 0.9%, 1.8%, and 2.5% (P =.11). Univariate analysis of the rate of >/=50% restenosis in 3 years for the 346 vein patched (2; 0.6%) and 186 Dacron graft patched (7; 3.8%) CEAs that did not have internal carotid artery shortening gave a P value of .015. Similarly, Kaplan-Meier method analysis of this subset of nonshortened CEAs gave a higher restenosis rate with Dacron graft patching (P =.012). With multiple logistic regression, the >/=50% restenosis rate was significantly associated with Dacron graft patching (P =.023; odds ratio, 4.5) and internal carotid artery shortening (P =.025; odds ratio, 3.1) and was weakly associated with female gender (P =.15; odds ratio, 2.0). Cox proportional hazards model analysis for >/=50% restenosis gave relative risk ratios of 3.0 (1.6 to 6.8; 95% confidence interval [CI]) for Dacron graft versus vein patching, 2.0 (1.2 to 3.3; 95% CI) for shortening versus not shortening, and 1.5 (0.9 to 2.4; 95% CI) for female versus male gender. CONCLUSION: CEA patching with Dacron grafts and saphenous vein grafts have similar low perioperative thrombosis, stroke, and death rates, although the stroke and death rates were slightly higher but not statistically different when Dacron grafts were used. Dacron graft patched CEAs are more likely to develop >/=50% restenosis than are those that are patched (+info)A comparative study of the rifampicin binding and elution characteristics for collagen- and albumin-sealed vascular grafts. (3/416)
OBJECTIVES: To assess the rifampicin binding and elution characteristics for three protein-sealed vascular grafts. DESIGN: In vitro study. MATERIALS: Cardial and Hemashield collagen-sealed and the DeBakey/Vasculour albumin-sealed vascular grafts. METHODS: The grafts were soaked in a 60,000 mg/l solution of rifampicin at 37 degrees C for 15 min. Bound drug was eluted from the grafts at 37 degrees C and at timed intervals the concentrations of rifampicin remaining in the grafts were determined. RESULTS: Although all three grafts contained high concentrations of rifampicin immediately after soaking these rapidly fell on washing and only a small fraction of the adsorbed rifampicin was tightly bound to the grafts. Rifampicin loading of this tightly bound fraction was similar for the two collagen-sealed grafts (1.7-2.0 mg/kg) but higher for the albumin-sealed graft (16.0 mg/kg). Elution of the tightly bound fraction appeared to follow first-order kinetics with elimination half-lives of 89-141 h. The concentrations of rifampicin remaining in the grafts after eight days were above those needed to inhibit sensitive staphylococci and were 0.7 mg/kg (collagen-sealed grafts) to 3.7 mg/kg (albumin-sealed graft). CONCLUSIONS: There is broad equivalence between the rifampicin binding and elution for the two collagen-sealed grafts, but there appears to be slightly higher binding for the albumin-sealed graft. (+info)Occlusion of the internal carotid artery by means of microcoils for preventing epistaxis caused by guttural pouch mycosis in horses. (4/416)
Occlusion of the internal carotid artery by insertion of intravascular platinum microcoils for guttural pouch mycosis was experimentally evaluated in 9 healthy adult Thoroughbred horses. The internal carotid artery was ligated to its origin, and an arteriotomy was made distal to the ligature, which was then occluded by insertion of the microcoil approximately 13 cm distal to its origin. Cessation of blood flow was determined visually and by angiography at the arteriotomy site. Six horses were evaluated for complication clinically and by endoscopy after surgery. One horse was necropsied after 30 days of surgery for histological evaluation of artery thrombus formation. In the other 3 horses, the blood flow of the right internal carotid artery was monitored, before and after microcoil occlusion of the left internal carotid artery. One or 2 microcoils stopped blood flow within a few minutes. No other abnormal findings were observed clinically. Thrombus was observed in the occluded segment of 1 horse 30 days after insertion; but no abnormalities were detected. The blood flow in the right internal carotid artery increased by approximately 28-58% after occlusion of the left internal carotid artery. This microcoil vascular occlusion technique causes an effective thrombosis, and based on experimental studies and clinical application in 2 horses with epistaxis due to guttural pouch mycosis, this technique would appear to be safe and efficacious. (+info)Bacterial resistance of refrigerated and cryopreserved aortic allografts in an experimental virulent infection model. (5/416)
PURPOSE: The bacterial resistance of refrigerated and cryopreserved aortic allografts in a highly virulent infection in a dog model was studied. METHODS: The infrarenal aorta of 12 dogs was replaced with either a cryopreserved aortic allograft (group I, n = 6) or a refrigerated aortic allograft (group II, n = 6) in infected sites. Allografts were harvested from dogs and stored for 1 week, either by cryopreservation (-140 degrees C) or refrigerated method (4 degrees C), in a preservation medium. At the time of implantation, induction of infection was achieved with an infected piece of knitted Dacron placed just beneath the allograft. The Dacron was contaminated in vitro by soaking it in a solution with Staphylococcus aureus PR209. All 12 dogs received no adjunct antibiotic or antithrombotic therapy. Four weeks after implantation, the animals were killed to recover the grafts for bacteriological and histological analyses. Bacterial results were expressed as colony-forming units (CFU)/cm2 of graft material. RESULTS: In group I, only one allograft grew bacteria at 2. 16 x 10(6 )CFU/cm2, with a blood culture positive for S aureus. In group II, one dog died at 3 weeks from a false septic aneurysm rupture, all the allografts were infected (P <.05) with a mean bacterial count of 9.41 +/- 6.8 x 10(4) CFU/cm2, and three blood cultures were positive for S aureus. The patency of the grafts was analyzed at the time of recovery. Three laminar thrombi without occlusion were present in group I; none were present in group II. A better preserved endothelium in group I was revealed by means of histologic analysis staining with factor VIII antibody before implantation. After 4 weeks of implantation in the infected site, infected allografts presented polynuclear infiltrates in the media with a high degree of inflammatory reaction, and endothelial recovery was more significant in group I, with numerous young plump cells. CONCLUSION: This study demonstrates that cryopreserved allografts implanted in infected sites in a dog model can produce greater bacterial resistance. (+info)Eversion endarterectomy versus open thromboendarterectomy and patch plasty for the treatment of internal carotid artery stenosis. (6/416)
OBJECTIVE: in 1996 we changed our treatment for stenosis of the internal carotid artery (ICA) from open thromboendarterectomy and PTFE-patch plasty (TEA) to eversion endarterectomy (EEA). DESIGN: retrospective study. METHODS: a total of 475 EEAs of the ICA were performed between 2/96 and 11/96. These results were compared to the results of TEA carried out between 2/94 and 11/94 (n=388). RESULTS: clamping and operation time were significantly shorter for EEA. Neurological complications included transient ischaemic attacks in 1. 0% in the EEA group versus 1.3% after TEA (p=0.72), minor strokes (0. 6% vs. 1.8%, p=0.10) and major strokes in 1.5% versus 1.1% (p=0.59). The rate of restenosis >50% was 2.5% after EEA and 10.2% after TEA. The only detectable difference of statistical significance in complication rates was in the lesions of the hypoglossal nerve (5.3% vs. 2.6%, p=0.04). CONCLUSIONS: EEA of the ICA is a safe procedure for carotid reconstruction with the additional advantages of short clamping time, possibility of simultaneous shortening of an elongated ICA, and no requirement for patching. (+info)Ascending aortic replacement with aortic valve reimplantation. (7/416)
BACKGROUND: Reimplantation of the native, structurally intact aortic valve within a Dacron tube graft in patients with aortic root aneurysms corrects annular ectasia and dilatation of the sinotubular junction. The durability of this valve repair with respect to the increased mechanical stress on valve cusps has been discussed, is quite controversial, and is yet unknown. METHODS AND RESULTS: From July 1993 to November 1998, a replacement of the ascending aorta with a repair of the aortic valve was performed in 75 patients (53 men and 22 women aged 50+/-19 years). Twenty-one patients (28%) had Marfan syndrome, and 11 patients (15%) had an aortic dissection, type Stanford A (6 acute, 5 chronic). In 17 patients (23%), concomitant replacement of the aortic arch was necessary. Clinical and echocardiographic follow-up was performed in 6- to 12-month intervals for a cumulative study period of 137 patient-years. No operative deaths occurred. Two patients (3%) died 5 and 20 months postoperatively. One additional patient experienced a transient ischemic attack within the first postoperative week. Three patients (4%) with progressive aortic insufficiency required aortic valve replacement after 9, 11, and 14 months. All other patients had no or mild aortic insufficiency. The repairs have now remained stable for +info)Comparative evaluation of externally supported Dacron and polytetrafluoroethylene prosthetic bypasses for femorofemoral and axillofemoral arterial reconstructions. Veterans Affairs Cooperative Study #141. (8/416)
PURPOSE: Currently, the choice of a vascular prosthesis for an extra-anatomic arterial bypass graft is left to the surgeon's preference because well-designed comparative evaluations have not been performed. The Department of Veterans Affairs Cooperative Study 141 was organized to identify whether there is improved patency with different prosthetic grafts for patients with femorofemoral or axillofemoral bypass grafts. METHODS: Between June 1983 and June 1988, patients at 20 Veterans Affairs Medical Centers who had aortoiliac occlusive disease but were not considered suitable candidates for aortic bypass surgery were randomized to receive either an externally supported polytetrafluoroethylene or Dacron bypass graft for an extra anatomic bypass. Doppler-derived ankle brachial indices (ABIs) were determined before the operation and serially after the operation. Patients were seen in follow-up every 3 months for the first year and every 6 months thereafter. All patients were instructed to take 650 mg of aspirin each day for the duration of the study. A bypass graft was considered to be patent if the Doppler-derived postoperative ABI remained significantly improved (0.15 units above the preoperative value), and additional clinical information (such as subsequent ABIs, angiograms, or operations) did not contradict these observations. RESULTS: Three hundred forty patients with femorofemoral bypass grafts and 79 patients with axillofemoral or axillofemorofemoral bypass grafts were randomized. The indication for the bypass operation was limb salvage in 72% of the patients. The assisted primary patency rate for a Dacron bypass grafting was 79% at 1 year, 63% at 3 years, and 50% at 5 years; for polytetrafluoroethylene bypass grafting, the patency was 77% at 1 year, 62% at 3 years, and 47% at 5 years. CONCLUSION: The overall results of this prospective randomized study suggest that the current choices of prosthetic bypass grafting have similar long-term patency in patients who undergo femorofemoral or axillofemoral vascular reconstruction. (+info)I'm sorry for any confusion, but "Polyethylene Terephthalates" is not a medical term. It is a type of polymer used in the manufacturing of various products, such as plastic bottles and textile fibers. Medically, you might encounter the abbreviation "PET" or "PET scan," which stands for "Positron Emission Tomography." A PET scan is a type of medical imaging that provides detailed pictures of the body's interior. If you have any medical terms you would like defined, I'd be happy to help!
I'm sorry for any confusion, but "Polyethylene" is not a medical term. It is a type of synthetic plastic that is commonly used in various industrial and consumer products. Medical definitions typically refer to substances or conditions related to human health, treatment, or disease processes. If you have any questions related to medical terminology or concepts, I'd be happy to help!
I believe there may be some confusion in your question as Polyethylenes are not a medical term, but rather a category of synthetic polymers commonly used in various industrial and medical applications. Here's a brief overview:
Polyethylene (PE) is a type of thermoplastic polymer made from the monomer ethylene. It is a versatile material with numerous applications due to its chemical resistance, durability, and flexibility. There are several types of polyethylenes, including:
1. Low-density polyethylene (LDPE): This type has a lower density and more branching in its molecular structure, which results in less crystallinity. LDPE is known for its flexibility and is often used in packaging films, bags, and containers.
2. High-density polyethylene (HDPE): HDPE has a higher density and less branching, resulting in greater crystallinity. It is more rigid than LDPE and is commonly used in applications such as bottles, pipes, and containers.
3. Linear low-density polyethylene (LLDPE): This type combines the flexibility of LDPE with some of the strength and rigidity of HDPE. LLDPE has fewer branches than LDPE but more than HDPE. It is often used in film applications, such as stretch wrap and agricultural films.
4. Ultra-high molecular weight polyethylene (UHMWPE): UHMWPE has an extremely high molecular weight, resulting in exceptional wear resistance, impact strength, and chemical resistance. It is commonly used in medical applications, such as orthopedic implants and joint replacements, due to its biocompatibility and low friction coefficient.
While polyethylenes are not a medical term per se, they do have significant medical applications, particularly UHMWPE in orthopedic devices.
Polyethylene glycols (PEGs) are a family of synthetic, water-soluble polymers with a wide range of molecular weights. They are commonly used in the medical field as excipients in pharmaceutical formulations due to their ability to improve drug solubility, stability, and bioavailability. PEGs can also be used as laxatives to treat constipation or as bowel cleansing agents prior to colonoscopy examinations. Additionally, some PEG-conjugated drugs have been developed for use in targeted cancer therapies.
In a medical context, PEGs are often referred to by their average molecular weight, such as PEG 300, PEG 400, PEG 1500, and so on. Higher molecular weight PEGs tend to be more viscous and have longer-lasting effects in the body.
It's worth noting that while PEGs are generally considered safe for use in medical applications, some people may experience allergic reactions or hypersensitivity to these compounds. Prolonged exposure to high molecular weight PEGs has also been linked to potential adverse effects, such as decreased fertility and developmental toxicity in animal studies. However, more research is needed to fully understand the long-term safety of PEGs in humans.
Prosthesis failure is a term used to describe a situation where a prosthetic device, such as an artificial joint or limb, has stopped functioning or failed to meet its intended purpose. This can be due to various reasons, including mechanical failure, infection, loosening of the device, or a reaction to the materials used in the prosthesis.
Mechanical failure can occur due to wear and tear, manufacturing defects, or improper use of the prosthetic device. Infection can also lead to prosthesis failure, particularly in cases where the prosthesis is implanted inside the body. The immune system may react to the presence of the foreign material, leading to inflammation and infection.
Loosening of the prosthesis can also cause it to fail over time, as the device becomes less stable and eventually stops working properly. Additionally, some people may have a reaction to the materials used in the prosthesis, leading to tissue damage or other complications that can result in prosthesis failure.
In general, prosthesis failure can lead to decreased mobility, pain, and the need for additional surgeries or treatments to correct the problem. It is important for individuals with prosthetic devices to follow their healthcare provider's instructions carefully to minimize the risk of prosthesis failure and ensure that the device continues to function properly over time.
Cathartics are a type of medication that stimulates bowel movements and evacuates the intestinal tract. They are often used to treat constipation or to prepare the bowel for certain medical procedures, such as colonoscopies. Common cathartic medications include laxatives, enemas, and suppositories.
Cathartics work by increasing the muscle contractions of the intestines, which helps to move stool through the digestive tract more quickly. They may also increase the amount of water in the stool, making it softer and easier to pass. Some cathartics, such as bulk-forming laxatives, work by absorbing water and swelling in the intestines, which helps to bulk up the stool and stimulate a bowel movement.
While cathartics can be effective at relieving constipation, they should be used with caution. Overuse of cathartics can lead to dependence on them for bowel movements, as well as electrolyte imbalances and other complications. It is important to follow the instructions carefully when using cathartic medications and to speak with a healthcare provider if constipation persists or worsens.
A hip prosthesis, also known as a total hip replacement, is a surgical implant designed to replace the damaged or diseased components of the human hip joint. The procedure involves replacing the femoral head (the ball at the top of the thigh bone) and the acetabulum (the socket in the pelvis) with artificial parts, typically made from materials such as metal, ceramic, or plastic.
The goal of a hip prosthesis is to relieve pain, improve joint mobility, and restore function, allowing patients to return to their normal activities and enjoy an improved quality of life. The procedure is most commonly performed in individuals with advanced osteoarthritis, rheumatoid arthritis, or other degenerative conditions that have caused significant damage to the hip joint.
There are several different types of hip prostheses available, each with its own unique design and set of benefits and risks. The choice of prosthesis will depend on a variety of factors, including the patient's age, activity level, overall health, and specific medical needs. In general, however, all hip prostheses are designed to provide a durable, long-lasting solution for patients suffering from debilitating joint pain and stiffness.
Prosthesis design is a specialized field in medical device technology that involves creating and developing artificial substitutes to replace a missing body part, such as a limb, tooth, eye, or internal organ. The design process typically includes several stages: assessment of the patient's needs, selection of appropriate materials, creation of a prototype, testing and refinement, and final fabrication and fitting of the prosthesis.
The goal of prosthesis design is to create a device that functions as closely as possible to the natural body part it replaces, while also being comfortable, durable, and aesthetically pleasing for the patient. The design process may involve collaboration between medical professionals, engineers, and designers, and may take into account factors such as the patient's age, lifestyle, occupation, and overall health.
Prosthesis design can be highly complex, particularly for advanced devices such as robotic limbs or implantable organs. These devices often require sophisticated sensors, actuators, and control systems to mimic the natural functions of the body part they replace. As a result, prosthesis design is an active area of research and development in the medical field, with ongoing efforts to improve the functionality, comfort, and affordability of these devices for patients.