Biomedical subjects

D S Baumann

Publications and source records attributed to D S Baumann.

8 recordsLinked to original sources

PubMed1996

Autologous vein-covered stent for the endovascular management of an iliac artery-ureteral fistula: case report and review of the literature.

Iliac artery-ureteral fistula is a rare entity that is being reported with increasing frequency. Patients with iliac artery-ureteral fistulas can be divided into two distinct groups on the basis of the factors that predispose them to having these fistulas. In group I the fistula is associated with degenerative iliac artery disease or previous arterial reconstructive surgery. Patients in group II have undergone some combination of the following procedures: pelvic extirpative surgery for malignancy, urinary diversion, radiation therapy, and ureteral stenting. The diagnosis of an iliac artery-ureteral fistula can be elusive even with the use of multiple imaging methods. Direct operative repair is technically demanding and is associated with high mortality rates. In recent years, treatment has shifted toward percutaneous embolization of the iliac artery and extraanatomic lower extremity vascular reconstruction for group II patients. In this report, the 24 group II patients with iliac artery-ureteral fistulas who previously have been described are reviewed, and a new endovascular treatment for this entity that uses a stented vein graft is detailed.

Aged↗

PubMed1996

Parathyroid autotransplantation during thyroidectomy. Results of long-term follow-up.

SUMMARY BACKGROUND DATA: Permanent hypoparathyroidism is a recognized complication of thyroidectomy. Operative strategies to prevent this complication include preservation of parathyroid glands in situ and autotransplantation of parathyroid glands resected or devascularized during thyroidectomy. METHODS: An analysis of 194 patients having thyroidectomy and simultaneous parathyroid autotransplantation at Barnes Hospital from 1990 to 1994 was performed. Data were collected regarding patient demographics, indication for thyroidectomy, operative procedure, pathologic diagnoses, and postoperative course, including biochemical assessment of parathyroid autograft function. RESULTS: Of 194 patients having either total, subtotal, or completion thyroidectomy, 104 (54%) experienced a [Ca(+2)]nadir less than or equal to 8.0 mg/dL and had symptoms and signs of hypocalcemia. Parathyroid autotransplantation was successful in 103 (99%) of these 104 cases and resulted in a 1.0% incidence of hypoparathyroidism in this series. CONCLUSIONS: Although preservation of parathyroid glands in situ is desirable, routine parathyroid autotransplantation during thyroidectomy virtually eliminates postoperative hypoparathyroidism. Normal parathyroid glands resected or devascularized during thyroidectomy for well-differentiated thyroid carcinoma or benign disease should be transplanted in the sternocleidomastoid muscle. Patients with Multiple Endocrine Neoplasia type 2A should have parathyroid glands resected at the time of thyroidectomy for medullary thyroid carcinoma and transplanted in the nondominant forearm. Postoperative management in most patients after thyroidectomy and parathyroid autotransplantation involves temporary calcium and vitamin D replacement and close biochemical evaluation. This precautionary measure of parathyroid autotransplantation markedly reduces the incidence of permanent postoperative hypoparathyroidism.

Adolescent↗

PubMed1994

An institutional experience with arterial atheroembolism.

Seemingly minor blue-toe lesions resulting from atheroemboli are associated with unstable atherosclerotic plaques, which are at risk for causing recurrent emboli, tissue loss, and potentially death. At Washington University Medical Center, 62 patients (31 males and 31 females), ranging in age from 38 to 89 years (mean 62.8 +/- 11.7 years), were treated for cutaneous manifestations of atheroembolic disease. Most patients (62%) had spontaneous bouts of atheroembolism, but 13 (21%) had recently undergone an inciting invasive radiologic study, 10 (16%) were on anticoagulation therapy, and one (2%) experienced abdominal trauma. In addition to the cutaneous manifestations, 18 patients (29%) also developed coincidental deterioration in renal function and four (6%) had intestinal infarction from atheroemboli. Arteriography in nearly all patients (97%) implicated the aorta and iliac arteries most commonly (80%), with the femoral (13%), popliteal (3%), and subclavian (3%) arteries less frequently incriminated. Forty-two patients underwent bypass grafting procedures (36 anatomic and six extra-anatomic) after exclusion of the native diseased artery, 20 patients had endarterectomies (six with additional bypass grafts), and five patients had no corrective vascular procedures. The 30-day operative mortality rate was 5% in this series. Nineteen patients (31%) required minor amputations, whereas two required major leg amputations. Thus limb salvage was possible in 86 of 88 (98%) limbs. No further episodes of atheroembolism occurred in the involved limbs during follow-up (1 to 53 months, mean 20.2 months). We advocate urgent arteriography and surgical correction or bypass with exclusion of the offending lesion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1994

The role of cholesterol accumulation in prosthetic vascular graft anastomotic intimal hyperplasia.

PURPOSE: To demonstrate that modulation of plasma cholesterol concentrations affects prosthetic vascular graft anastomotic intimal hyperplasia (AIH), aortic grafts were examined histologically and biochemically in 41 rabbits. METHODS: Twenty-seven rabbits were fed standard rabbit diet, whereas 14 were fed cholesterol-supplemented diet to induce hypercholesterolemia. RESULTS: A smooth muscle cell proliferative response, similar to AIH in humans, was seen equally at the proximal and distal anastomoses. However, surface area and thickness of AIH were significantly greater in rabbits with hypercholesterolemia. Anastomotic tissue cholesterol concentrations were fifteenfold higher in rabbits with hypercholesterolemia than in rabbits with normal cholesterol concentrations and anastomotic cholesterol concentrations were fivefold higher than in the aorta away from the graft in rabbits with hypercholesterolemia. Preferential deposition of radioiodinated dilactitol tyramine coupled to low-density lipoproteins, but not albumin, was demonstrated in anastomotic areas and grafts of rabbits with normal cholesterol concentrations as well. Surface area and thickness of AIH correlated closely with plasma and tissue cholesterol concentrations. CONCLUSIONS: Oxidized products of lipoproteins have been shown to stimulate production of growth factors that cause smooth muscle cell proliferation, migration, and synthetic function. It is likely they play an important part in prosthetic vascular graft AIH, similar to their role in atherogenesis.

Anastomosis, Surgical↗

PubMed1994

Probucol reduces the cellularity of aortic intimal thickening at anastomotic regions adjacent to prosthetic grafts in cholesterol-fed rabbits.

Intimal hyperplasia is a persistent problem after implantation of prosthetic grafts. Although the mechanisms underlying this hyperplastic response are unknown, it has been proposed that such responses may be due to chronic vascular injury similar to that of atherogenesis. Thus, the role of oxidation was explored using the potent antioxidant drug probucol. Adult New Zealand White rabbits fed a modestly (0.25%) cholesterol-enriched diet had a polytetrafluoroethylene prosthetic graft placed into the lower aorta. After the grafting procedure, a group of 11 rabbits was placed on the cholesterol-enriched diet supplemented with 1% wt/wt probucol while a control group of 10 rabbits was placed on the cholesterol-enriched diet alone. The rabbits were maintained for a further 10 weeks before histological examination of the area surrounding the graft. Although administration of probucol did not significantly alter the dimensions of lesions at the anastomotic sites, the drug promoted striking histological changes in the surrounding tissue. Both groups of rabbits had a similar intimal hyperplastic response of the aortic tissue surrounding the graft. The vascular lesions present in the perigraft region of the control group consisted of a normal-appearing media but a thickened intima. The thickened intima contained numerous smooth muscle cells in a network of extracellular matrix. Regions in the neointima that were rich in smooth muscle cells exhibited modest staining for proliferating cell nuclear antigen. A few macrophages were present in the control group as determined by immunostaining with the monoclonal antibody RAM-11. In contrast, administration of probucol led to a marked reduction in the presence of RAM-11-staining macrophages.(ABSTRACT TRUNCATED AT 250 WORDS)

Anastomosis, Surgical↗

PubMed1993

Preservation of renal function in juxtarenal and suprarenal abdominal aortic aneurysm repair.

PURPOSE: Deterioration in renal function is a common cause of morbidity in patients treated surgically for juxtarenal and suprarenal abdominal aortic aneurysms. We reviewed our experience over the last 8 years with 65 consecutive patients undergoing juxtarenal (n = 31) or suprarenal (n = 34) abdominal aortic aneurysm repair. METHODS: The aneurysms were repaired with a transabdominal (n = 8), thoracoabdominal (n = 4), retroperitoneal (n = 22), or thoracoretroperitoneal (n = 31) approach. Proximal aortic clamps were placed at the suprarenal, supra-superior mesenteric artery, or supraceliac level. Renal hypothermia with cold heparinized saline solution renal artery perfusion was used to protect renal function in 38 patients with either preoperative renal insufficiency or with anticipated prolonged renal ischemia (> 30 minutes). Concomitant renal artery reconstruction was required in 30 patients. RESULTS: Significant operative morbidity developed in 23 (35.3%) patients. There was one (1.53%) perioperative death (0 to 90 days). Temporary dialysis was necessary in two patients. Preoperative renal insufficiency was a significant risk factor on multivariate analysis for a decline in renal function during the first postoperative week. However, serum creatinine concentration had returned to baseline or improved in all patients but two (3.1%) at the time of discharge. In spite of significantly longer renal ischemia, discharge creatinine levels were, on univariate analysis, statistically less than baseline creatinine levels in patients with suprarenal aneurysms, patients requiring renal reconstruction, and patients treated with renal hypothermia. The location of the proximal aortic clamp was not a factor in postoperative morbidity. There was no significant difference between juxtarenal and suprarenal aneurysms with respect to operating room time, transfusion requirements, days intubated, resumption of oral diet, or the length of hospitalization. CONCLUSIONS: Careful consideration of the route of exposure, location of the proximal aortic clamp, and the preservation of renal function with renal hypothermia and with the repair of significant renal artery lesions will result in minimal morbidity and mortality in patients requiring surgery for juxtarenal or suprarenal abdominal aortic aneurysms.

Aged↗

PubMed1993

Does crossing the legs decrease arterial pressure in diabetic patients with peripheral vascular disease?

OBJECTIVE: To evaluate the effect of crossing the legs at the knee and the ankle on peripheral arterial pressures. RESEARCH DESIGN AND METHODS: A prospective study of 6 diabetic patients with known peripheral vascular disease and 5 nondiabetic control subjects without peripheral vascular disease was conducted. Peripheral arterial pressures were taken at the ankle and at the great toe before and after crossing the legs at the knees and ankles. Comparisons were made of measurements obtained in the supine and sitting positions. All crossed leg measurements were taken in the sitting position. RESULTS: Ankle arm indexes and digital arm indexes pressures taken in the sitting position were equal to or higher than supine pressures, with the exception of one subject, GB. In this patient, ankle arm indexes and digital arm indexes on the right extremity were lower in the sitting position, but increased with the legs crossed at the knees and ankles compared with the uncrossed sitting position. In all patients, lower extremity pressures that decreased slightly with crossing the legs remained higher than pressures obtained in the supine position. Statistical analyses showed no significant differences. Wave forms did not change even when there was a slight decrease in ankle arm indexes or digital arm indexes. Control subjects without peripheral vascular disease showed no change in pressures with crossing the legs. CONCLUSIONS: Crossing the legs at the knees and ankles does not result in a significant decrease in peripheral arterial pressures in diabetic patients with peripheral vascular disease.

Analysis of Variance↗

PubMed1993

Parathyroid autotransplantation.

It has been clearly shown clinically that parathyroid tissue can be successfully autotransplanted and even allotransplanted if the host is immunosuppressed. Engraftment is almost always successful; however, if abnormal tissue has been transplanted, its function will continue to be abnormal if the same intrinsic (e.g., primary parathyroid hyperplasia) or extrinsic (renal osteodystrophy) stimulation existing before grafting continues in the postoperative period. In these patients the secretion of parathyroid hormone from the grafted parathyroid tissue can be shown to progressively increase with time. Although parathyroid autotransplantation is most frequently performed clinically for renal osteodystrophy, there is controversy about the operation, and some surgeons prefer the technique of 3 1/2 gland parathyroidectomy. Because of the generally good results with total parathyroidectomy and autotransplantation in patients with primary parathyroid hyperplasia, this procedure seems to be the operation of choice in this clinical setting. The clearest indication for parathyroid autotransplantation is in patients with radical operations on the thyroid gland or other head and neck organs where the parathyroids have been damaged or their viability is questioned.

Chronic Kidney Disease-Mineral and Bone Disorder↗