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Biomedical subjects

G A Beathard

Publications and source records attributed to G A Beathard.

At least 19 recordsLinked to original sources
PubMed1999

Salvage of the nonfunctioning arteriovenous fistula.

Two factors are necessary for an arteriovenous fistula (AVF) to be usable as dialysis access. It must have adequate blood flow, and it must have a size that will allow for cannulation. An AVF can remain patent in the face of relatively low blood flow. For effective dialysis, the AVF only has to deliver a blood flow that is marginally greater than the pump rate. Unfortunately, dialysis may not be technically possible in these cases with lower flow because the AVF does not mature sufficiently to a size adequate for cannulation. In this prospective observational series of 63 patients, failure of AVF development was the result of venous stenosis and/or the presence of accessory veins (venous side branches). The presence of these anomalies could be diagnosed by physical examination. After documentation by angiography, the patients were treated with angioplasty, venous ligation, or a combination of both. Three levels of venous ligation were performed depending on individual requirements: ligation of accessory veins (AVL), ligation of the median cubital vein, and temporary banding of the main fistula itself. The determining factor was the appearance of the fistula after each of the procedures was accomplished relative to potential for cannulation. Of these 63 patients with nonfunctional fistulae that ranged in age from 33 to 418 days, access was salvaged in 52 patients (82.5%). This included 9 of 12 patients who required repeat procedures. The results of this study validate angioplasty and AVL as therapy for the salvage of AVFs that fail to develop.

Adult↗
PubMed1999

Management of bacteremia associated with tunneled-cuffed hemodialysis catheters.

The dominant problem associated with the use of tunneled-cuffed catheters is infection. When this occurs, two issues must be addressed: treatment of the infection and management of the catheter. The purpose of this 2-yr study was to report the results of a prospective observational series in which catheter management was based on the clinical picture presented by the patient. Data were collected on patients with catheter-related bacteremia (CRB) dealt with in one of three ways: (1) minimal symptoms with a normal-appearing tunnel and exit site (exchange over guidewire within 48 h of antibiotic initiation [Xchng group], 49 cases); (2) minimal symptoms but with tunnel or exit site infection (exchange over a guidewire with creation of a new tunnel [Nutunl group], 28 cases); and (3) severe clinical symptoms (catheter removal with delayed replacement after defervescence [Delay group], 37 cases). All cases were treated immediately with empiric antibiotics followed by 3 wk of antibiotic therapy based on culture sensitivities. A cure was defined as a 45-d symptom-free interval after antibiotic therapy was complete. A cure rate total of 87.8% for the Xchng group, 75% for the Nutunl group, and 86.5% for the Delay group was seen for the 114 episodes of CRB. It is concluded that in selected patients, catheter exchange over a guidewire within 48 h of antibiotic initiation followed by 3 wk of specific antibiotic therapy is a viable treatment option. Additionally, replacing the catheter in patients presenting with severe symptoms of sepsis as soon as they have defervesced is a reasonable approach to therapy.

Adult↗
PubMed1996

Mechanical thrombolysis for the treatment of thrombosed hemodialysis access grafts.

PURPOSE: To evaluate the data acquired over 2 1/2 years regarding the use of mechanical thrombolysis as the routine, preferred treatment for thrombosed access grafts in a large patient population undergoing hemodialysis. MATERIALS AND METHODS: Mechanical thrombolysis was performed in 1,176 cases. Data were collected on the success rate, complication rate, long-term patency, and presence and location of stenosis. The results of mechanical thrombolysis were compared with those of surgery. All data were collected prospectively. RESULTS: Thrombosed grafts were treated successfully in 1,123 of 1,176 cases (95%). Minor complications occurred in 34 cases (3%). Venous stenosis was present in 1,054 cases (90%). Long-term patency rates were 74% at 30 days, 52% at 90 days, and 17% at 360 days. The thrombosis rate per patient per year and the number of patients who required graft revision or replacement decreased in comparison with the results obtained with surgical treatment. CONCLUSION: Mechanical thrombolysis was effective, quick, and safe. Percutaneous treatment should be adopted as the treatment of choice for thrombosed hemodialysis access grafts.

Anesthetics, Local↗
PubMed1995

Thrombolysis versus surgery for the treatment of thrombosed dialysis access grafts.

Thrombolysis offers several advantages over surgery in the treatment of thrombosed dialysis access grafts. This study was undertaken to compare the results obtained when thrombolysis was used as the preferred treatment (Thrombolysis Period) for this problem in comparison with the results that had been obtained when surgical therapy had been the preferred treatment (Surgery Period). Each period of study lasted 12 months and the two periods ran consecutively. All data were collected prospectively. No significant problems were encountered when thrombolysis was substituted for surgical therapy as the preferred treatment of thrombosed dialysis access grafts. During the Surgical Period there were 580 thrombotic episodes, a rate of 0.86 per patient. During the Thrombolysis Period there were 568 episodes, a rate of 0.76. These differences were not statistically significant. During the Thrombolysis Period, thrombolysis was found to be as effective as surgery had been during the Surgical Period in the initial treatment of thrombosed grafts. The rate of surgical revision was decreased by two-thirds during the Thrombolysis Period, but the rate of graft replacement was not altered. Long-term patency after therapy by thrombolysis during the Thrombolysis Period was superior to that for surgical thrombectomy performed during the Surgical Period, and was equal to that for revision and graft replacement. The complication rate for thrombolysis was low and complications were managed easily without sequelae. It is concluded that thrombolysis is safe and, when used as the preferred treatment for thrombosed dialysis access grafts, is as effective as surgical therapy. Since it preserves potential vascular access sites and yields long-term patency rates superior to those for surgical thrombectomy, it should be regarded as the treatment of choice for this problem.

Follow-Up Studies↗
PubMed1994

The treatment of vascular access graft dysfunction: a nephrologist's view and experience.

Chronic hemodialysis, as it is practiced today, is heavily dependent on the use of the expanded polytetrafluoroethylene graft for vascular access, although it is prone to the problem of venous stenosis and its sequela, thrombosis. The natural history of untreated venous stenosis is to decrease the efficiency of dialysis and to limit the life expectancy of the graft. Prospective treatment of venous stenosis has been advocated and percutaneous transluminal angioplasty (PTA) has been shown to be safe and reasonably effective for this purpose. Because there is no optimum screening test for venous stenosis, patient selection for PTA is particularly important. The use of a group of clinical indicators that serve to indicate a significant degree of graft dysfunction has been recommended for this purpose. Long-term patency may be better when venous stenosis is surgically revised; however, PTA has a number of advantages, especially the preservation of potential vascular access sites. Endovascular metallic stents have been used to preserve patency following PTA with disappointing results except in selected cases with central lesions. Three types of percutaneous thrombolysis have been studied for the treatment of thrombosed access grafts. The technique of pharmacological thrombolysis in which a lytic enzyme is infused into the clotted graft has proven to be unsatisfactory. The more recently developed technique of pharmacomechanical thrombolysis (PMT) has proven to be practical for use in the dialysis patient. This procedure consists of two components, a pharmacological phase in which lytic enzyme is administered and a mechanical phase in which the residual clot is macerated and removed to restore flow. This technique offers the benefits of being quick, effective, and safe. Additionally, it combines angiographic evaluation of the access, thrombolysis, and angioplasty of stenotic lesions. Mechanical thrombolysis, performed in a manner identical to PMT except that saline is used in place of the lytic enzyme, has been shown to be equally effective and safe.

Angioplasty↗
PubMed1994

Mechanical versus pharmacomechanical thrombolysis for the treatment of thrombosed dialysis access grafts.

Pharmacomechanical thrombolysis offers the first practical approach for non-surgical therapy of thrombosed dialysis access grafts. This technique involves both lysis using a fibrinolytic enzyme and mechanical maceration of the clot. The technique can be accomplished in a short period of time, has a high degree of success and has a low level of complications. To evaluate the effectiveness of the mechanical aspects of this technique used alone without the lytic enzyme, a study was designed in which 103 cases of thrombosed PTFE grafts were randomly assigned to either a mechanical (M) group consisting of 55 cases or a pharmacomechanical (PM) group consisting of 48 cases. Both groups were treated in an identical manner using crossed pulse-spray catheters, except that in the M group heparinized saline was used as the pulsing agent while in the PM group concentrated urokinase was used. The two groups were completely comparable in all other respects. The combined procedure of thrombolysis and angioplasty was successful in restoring flow in 92.8% of the M group and 93.8% of the PM group. Life table analysis revealed 74%, 65%, 58% and 37% function in the M group at 15, 30, 60 and 90 days, respectively. The rates for the PM group at the same time intervals were 77%, 72%, 62% and 46%. In none of these parameters was there any significant difference between the two groups. The mean time required for the procedure in the M group was shorter because of the time delay between pulses of enzyme in the PM group built into the technique which was used.(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1993

Gianturco self-expanding stent in the treatment of stenosis in dialysis access grafts.

This study evaluated the effectiveness of the Gianturco endovascular stent in preserving graft patency following percutaneous transvenous angioplasty (PTVA) of stenotic lesions occurring at the graft-vein anastomosis in hemodialysis patients with polytetrafluoroethylene grafts. Fifty-eight patients having 50% or greater stenosis were randomly divided into a treatment group (N = 28) and a concurrent control group (N = 30) following PTVA. In the treatment group, a stent was placed following dilatation. Graft thrombosis, the need for surgical revision, or the need for a repeat PTVA were used as end point events. The period of time from the PTVA/stent procedure to the end point event was referred to as the duration of efficacy (DE). By life table analysis, the DE for the treatment group was 100% at 30 days, 91% at 60 days, 85% at 90 days, 72% at 180 days, and 17% at 360 days. Comparison of the characteristics and results obtained in the treatment group and that of the concurrent control group revealed no significant difference in any parameter prior to treatment, in the response to PTVA, or in the DE of the procedure performed. It was concluded that the stent offered no advantage in the treatment of the graft-vein anastomosis stenotic lesion affecting PTFE dialysis access grafts.

Angioplasty↗
PubMed1992

Percutaneous transvenous angioplasty in the treatment of vascular access stenosis.

This study was undertaken to evaluate percutaneous transvenous angioplasty (PTVA) for the treatment of all types of vascular access stenosis in a large population of dialysis patients. Stenoses were identified by venography in patients who met a set of clinical criteria indicating the need for evaluation. The lesions were classified by location and type. Data were collected prospectively and analyzed separately for each lesion type. A total of 536 PTVA procedures was performed in 285 patients. This included 107 cases of long venous stenosis (> 6 cm) and 149 cases of mid-graft stenosis. In the total group, an initial success rate of 94% was obtained (80% or greater dilatation). A decrease in VPm (venous pressure measured on dialysis) of 35.9%, 32.4%, and 22.6% was seen at one week, one month, and three months, respectively. At 90 days, 180 days, and 360 days 90.6%, 61.3%, and 38.2%, respectively, of the treated grafts were continuing to be patent and functional with no need for repeat PTVA treatment. Repeat treatments for recurrent lesions were as successful as the initial treatment. It is concluded that vascular access stenosis can be easily diagnosed and that all categories of stenotic lesion can be effectively treated with PTVA.

Angioplasty, Balloon↗
PubMed1977

Development of the characteristic ultrastructural lesion of hereditary nephritis during the course of the disease.

The diagnosis of hereditary nephritis in the absence of a clear family history or the presence of characteristic ancillary abnormalities is difficult, but it has considerable prognostic importance. The recent recognition of an ultrastructural lesion characteristic of this disease, although not present in all families, is of considerable value. In this report we describe a kindred with the lesion-associated disease that differs from those previously described in that the lesion developed during the course of the disease, was not present in all affected members and appeared to be the result of paternal transmission.

Adolescent↗
PubMed1977

Nephronophthisis. Renal function and histologic studies in a family.

Nephronophthisis (previously described as familial juvenile nephronophthisis and medullary cystic disease) is characterized by insidious renal failure, its main features being increased urinary sodium loss, pitressin-resistant hypotomic polyuria, polydipsia, normal urine sediment and absence of hypertension. Renal function and histologic studies were performed in a family in which two siblings had this disorder, while the parents and two other siblings appeared clinically normal. Both parents demonstrated a moderate impairment of maximum urinary concentration. The values for tubular free water reabsorption (TcH2O) were relativley normal in the parents and the healthy siblings. One of the index patients showed only minimal sodium wasting even though he had hyposthenuria, thus suggesting an involvement of the collecting ducts in the early stage of neophronophthisis. No evidence of proximal tubular dysfunction was found. Although the light-microscopic examination of renal biopsies from the parents and the healthy siblings was unremarkable, electron microscopy revealed probable abnormalities in all four. An autosomal recessive mode of inheritance is, therefore, suggested in this family. The etiology of nephronophthisis is obscure but a likely possibility is that the renal damage results from an inborn metabolic error.

Adolescent↗
PubMed1976

The nephrotic syndrome associated with neoplasia: an unusual paraneoplastic syndrome. Report of a case and review of the literature.

The nephrotic syndrome complicating malignancy in the absence of renal vein thrombosis, amyloid or neoplastic infiltration of the kidney is an unusual occurrence. A case of diffuse, well differentiated, lymphocytic lymphoma and lipoid nephrosis documented by light microscopy, electron microscopy and immunofluorescent studies is reported. A review of the literature revealed 76 case reports in which the nephrotic syndrome was associated with neoplasia. The most frequently associated neoplasms are Hodgkin's disease, various carcinomas, nonHodgkin's lymphoma and leukemia in descending order. The most frequent renal lesion in patients with the nephrotic syndrome associated with various carcinomas is membranous glomerulonephritis (81 per cent) as opposed to patients with lymphomas or leukemias who have predominantly lipoid nephrosis (60 per cent). The evidence is reviewed suggesting that the lesions in membranous nephropathy are immunologically mediated by tumor or viral antigen-antibody complexes and in lipoid nephrosis perhaps by a defect in t-lymphocyte function.

Aged↗
PubMed1975

B-lymphocytosis factor in human plasma.

Patients with acute thermal burns experience an increase of serum immunoglobulins associated with marked B-lymphocytosis during the recovery phase from the burn injury. This study was performed to delineate humoral factors which may induce the B-lymphocytosis in such patients. Plasma samples were obtained serially from 14 adult patients and 14 adult controls. One-half ml of plasma was injected intraperitoneally into C3H/He male mice, and absolute numbers of surface immunoglobulin-bearing cells in the mouse peripheral blood were counted. Fractionation of plasma samples was performed. The biologically active plasma fraction, tentatively termed B-lymphocytosis factor (BLF), was cultured with normal human peripheral blood lymphocytes to determine in vitro lymphocyte transformation. The solubility of 125I-labelled BLF in various organic solvents was examined. Plasma obtained from burned patients induced a marked increase of IgG, IgA, and IgM-bearing cells in the peripheral blood of mice within 3 hours after injection. The B-lymphocytosis activity of normal plasma was not significant. The molecular weight of BLF was estimated to be close to that of ribonuclease A (M.W. 13,400). Transformation of normal human peripheral blood lymphocytes was observed when cultured with BLF. 125I-labelled BLF was not soluble in organic solvents. These data suggest that BLF is not a lipopolysaccharide, and plays a role in regulation of B-lymphocyte levels in burned patients.

Adolescent↗
PubMed1975

Smooth muscle in lymph node capsule and trabeculae.

This study focuses on the confusion in existing literature concerning the presence of smooth muscle in the capsule and trabeculae of lymph nodes. Human and bovine nodes from several anatomical areas and several individuals of each species were examined by conventional light, electron and fluorescence microscopy. Smooth muscle cells, independent of blood vessels, were demonstrated in the trabeculae and capsules of lymph nodes of both species examined by all three techniques. The need for further study on the function of these cells is indicated.

Animals↗
PubMed1975

Oubain-sensitive adenosine triphosphatase from human kidneys.

Adenosine triphosphatase (ATPase) was studied in tissue homogenates and subcellular fractions derived from human cadaver kidneys maintained in an organ preservation unit for transplantation. The activity of ouabain-sensitive ATPase was highest in the medulla, intermediate in the cortex and lowest in the papilla. The cortical enzyme activity diminished with time during maintenance perfusion of the kidneys. Similar concentrations of K+, Na+, Mg++, ATP and MgATP were required for half-maximal rates of ouabain-sensitive ATPase activity from the cortex or the medulla. The sensitivity of the enzyme to ouabain from both parts of the kidney was similar. K+ antagonized inhibition of the enzyme by ouabain. Chlormerodrin, mersalyl, mercaptomerin and ethacrynic acid were inhibitors of the enzyme.

Adenosine Triphosphatases↗