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Biomedical subjects

M W Webster

Publications and source records attributed to M W Webster.

At least 127 records · Page 7Linked to original sources
PubMed1984

Bacterial presence in aortic thrombus at elective aneurysm resection: is it clinically significant?

Infected thrombus in an abdominal aortic aneurysm represents a potential source of subsequent aortic graft sepsis. Previous reports have documented a 10 to 15 percent incidence of positive results of culture of the contents of an abdominal aortic aneurysm and have recommended prolonged postoperative organism-specific antibiotic therapy when a positive culture is encountered. In our study, we cultured the intraluminal thrombus during elective aneurysm repair in 64 patients with abdominal aortic aneurysms and found bacterial growth in 9 (14 percent of all patients). Eight of the nine patients received no antibiotic therapy other than the routine prophylaxis regimen, and no evidence of either early or late prosthetic graft sepsis occurred (mean follow-up 25 months). We conclude that a positive result of culture may not imply clinical infection at the time of operation and that prolonged postoperative organism-specific antibiotic therapy does not appear necessary in the patient with an asymptomatic aneurysm and no overt evidence of infection of the aneurysm at the time of operation.

Aneurysm↗
PubMed1984

Upper arm graft fistula for hemodialysis.

The repeated failure of forearm hemodialysis access grafts in patients with end-stage renal failure often requires the use of an upper arm graft fistula. During a 7-year period, 20 upper arm graft fistulas were placed in 15 patients. The 5-year patency rate by life-table analysis, including graft fistula salvage by thrombectomy, is 53%. The mean survival from graft insertion until revision or thrombectomy is 36 months. Twenty of the twenty-two thrombectomies performed (91%) were successful in reestablishing graft fistula patency. Six grafts required more than one thrombectomy, and seven grafts required revision of the venous anastomosis. Only one arterial anastomosis required revision. We conclude that the upper arm graft fistula is an acceptable method of hemodialysis access in those patients without suitable forearm access sites. However, an aggressive approach to both graft fistula thrombectomy and the revision of stenotic anastomoses is necessary to maintain a satisfactory patency rate.

Adult↗
PubMed1984

Seven-year follow-up of expanded polytetrafluoroethylene (PTFE) femoropopliteal bypass grafts.

Expanded polytetrafluoroethylene (PTFE) grafts have proven to be an acceptable short-term alternative for femoropopliteal reconstruction in those patients without suitable autologous saphenous vein. One hundred and twenty-seven femoropopliteal arterial bypass operations utilizing PTFE grafts were performed in 105 patients. Seven-year follow-up is now available for 20 grafts, 6-year follow-up for 47 grafts, and 5-year follow-up for 62 grafts. Graft occlusion was determined by angiography, Doppler assessment, loss of previously palpable pulses, or return of symptoms. Thirty nonocclusive graft losses were due to death, infection, aneurysm, amputation, or proximal occlusive disease. Overall cumulative patency rate, according to occlusive criteria alone and calculated by the life-table method, was 74% at 6 months, 63% at 1 year, 48% at 3 years, 40% at 5 years, and 35% at 7 years. Excluding early bypass failures (less than 1 year patency), 75% of grafts were patent at 3 years, 63% at 5 years, and 55% patent 7 years following operation. Diabetes mellitus was associated with a significantly lower patency rate. Patency rates were not adversely affected by graft diameter, distal popliteal anastomotic site, number of patent runoff vessels, preoperative symptoms, or prior arterial reconstruction. In patients without suitable autologous saphenous vein, the PTFE graft has proven to be a durable and dependable long-term alternative for femoropopliteal reconstruction.

Adult↗
PubMed1984

Carotid endarterectomy in patients with asymptomatic intracranial aneurysm.

The patient with symptomatic extracranial carotid artery disease who, on angiography, is found to have a coexisting intracranial aneurysm presents a therapeutic dilemma. Relief of the carotid stenosis, with a potential increase in cerebral blood pressure, might increase the risk of aneurysm rupture. Conversely, repair of the aneurysm may be hazardous because of the low flow imposed by the carotid stenosis, particularly in the event of perioperative hypotension. We reviewed 19 patients treated with 20 carotid endarterectomies in the face of concurrent asymptomatic intracranial aneurysm. There were no instances of aneurysm rupture during the operation or the 30 days following operation. The literature reported to date consists of a total of 20 patients with only one incidence of aneurysm rupture in the postoperative period. We conclude that carotid endarterectomy is unlikely to precipitate rupture of an intracranial aneurysm during the operation or postoperative period.

Aged↗
PubMed1984

Enalapril in heart failure.

Serum MK-422 and plasma angiotensin converting enzyme activity were measured during the introduction of enalapril therapy in eight patients with heart failure. In a second study of 16 patients, we recorded exercise tolerance, clinical status and haemodynamics before and after 12 weeks of placebo or enalapril treatment. Increasing doses of enalapril gave step-wise increments in serum MK-422. Plasma converting enzyme activity remained low for at least 24 h after each dose of enalapril (5, 10 and 20 mg). Compared to placebo patients (n = 8), those receiving enalapril (n = 8) tended to improve their exercise performance and clinical status, and showed a fall in right heart pressures after 12 weeks of treatment.

Aged↗
PubMed1982

Carotid endarterectomy under regional (conductive) anesthesia.

Carotid endarterectomy is reliable in the prevention of strokes due to arteriosclerotic disease at the carotid bifurcation. This is a retrospective review of 314 carotid endarterectomies performed at the University Health Center of Pittsburgh. The objectives of the study were to determine if regional anesthesia was a safe technique for carotid endarterectomy and to determine whether the neurologic complications that occurred were embolic or ischemic in origin. In patients who were neurologically intact before operation, the perioperative mortality was 0.88% and the incidence of neurologic complications was 3.1%. This is comparable to the current literature. Observations of the awake patient suggested that half the neurologic deficits that occurred in this series were due to embolization rather than to cerebral ischemia. Further more, the incidence of non-neurologic complications under general anesthesia was 12.9%. Under regional anesthesia, the incidence of non-neurologic complications was 2.8%. The data supports carotid endarterectomy under regional block as safe and reliable method.

Anesthesia, Conduction↗
PubMed1982

Causes of stroke in carotid endarterectomy.

Carotid endarterectomy performed with the patient conscious under regional anesthesia provides a unique opportunity to determine the time of onset of a neurologic deficit and in deduce a likely cause. If a trial period of carotid occlusion is tolerated without the development of a neurologic deficit (96% of our patients), operation may continue without indwelling shunt. Of the 345 patients who had elective carotid endarterectomies performed without shunt, neurologic deficits lasting longer than 24 hours developed in 6 patients (1.7%), and deficits resolving within 24 hours occurred in 15 patients (4.3%). The neurologic deficit developed during carotid dissection in 3 patients, during carotid occlusion in 1 patient, upon release of carotid occlusion in 2 patients, and in the first 5 postoperative days in 15 patients. Of the 15 postoperative deficits, 9 were transient ischemic attacks similar to preoperative episodes, 4 were strokes, and 2 were visual changes. Twenty of 21 deficits were thromboembolic, reperfusion phenomena or were related to hypotension. Only one (0.3% of 345 cases) could be attributed to cerebral anoxia. We believe comparison of raw stroke rates is not valid in comparing methods of cerebral protection, since most perioperative neurologic deficits are not attributable to hypoperfusion. Furthermore, trial carotid occlusion in the conscious patient is a satisfactory method for determining the need to use a shunt.

Aged↗
PubMed1981

Expanded polytetrafluoroethylene femoropopliteal grafts: forty-eight-month follow-up.

Ninety-eight expanded polytetrafluoroethylene (PTFE) grafts were used for femoropopliteal reconstruction in 81 patients. Forty-eight-month follow-up is now available for 20 grafts and 36-month follow-up is available for 51 grafts. Seventy-four percent of the patients were men. Thirty-one percent had diabetes mellitus, 38% had hypertension, 36% had atherosclerotic heart disease, 18% had prior myocardial infarction, 17% had a previous operation for aortoiliac disease, and 14% had a previous ipsilateral femoropopliteal bypass procedure. The indication for operation was claudication in 47%, rest pain in 20%, and ischemic pregangrene or gangrene in 32% of patients. Distal runoff was angiographically graded as good (76%) or poor (24%). Seventy-three grafts were anastomosed to the proximal or midpopliteal artery (above the knee); 25 grafts were anastomosed to the distal popliteal artery (below the knee). Graft occlusion was determined by the return of ischemic symptoms, disappearance of previously palpable pulses, or by angiographic or Doppler assessment. There were no operative deaths. Nonocclusive causes of graft loss were death (7), amputation (2), infection (2), and aneurysm (5). The overall cumulative patency rate calculated by the life-table method, according to the criterion of occlusion alone, was 75% at 6 months, 68% at 2 years, 58% at 3 years, and 48% at 4 years. Preoperative symptoms, the number of patent outflow vessels, popliteal anastomosis placed above or below the knee, or hypertension did not adversely affect graft patency. Diabetes mellitus was associated with significantly increased graft failure. The PTFE graft is an acceptable alternative for femoropopliteal reconstruction for the patient without a suitable autologous saphenous vein.

Aged↗
PubMed1979

Hepatic adenoma associated with portasystemic shunting in a young woman.

The development of a hepatic adenoma is described in a young female of reproductive age who had documented portasystemic shunting and hyperestrogenemia. The intrinsic hyperestrogenemia and the increased hepatic arterial blood flow, both of which occurred as a result of the portasystemic shunting secondary to portal venous obstruction, may have been important factors in the development of her hepatic tumor. We would postulate that prolonged endogenous hyperestrogenemia, like exogenous sex steroids, may predispose to hepatic adenoma formation.

Adult↗
PubMed1979

Expanded microporous polytetrafluoroethylene as a vascular substitute: a two year follow-up.

Since 1974, 131 femoropopliteal, distal popliteal, and tibial bypasses have been performed using expanded microporous polytetrafluoroethylene (PTFE). Forty patients were operated on for limb salvage, and 21 had had previous bypass procedures. The overall patency rate was 82%. Early occlusions possibly were related to technical error, but most probably were due to severity of disease and poor runoff. Late occlusions were related to progressive atherosclerosis in the proximal or distal arterial tree. A 75.7% cumulative patency rate was noted at 28 months. In man the PTFE prosthesis demonstrates a smooth intimal lining with fibroblastic ingrowth into the interstices of the graft. These results are considered to be excellent in this high-risk patient population. The patency rates achieved with PTFE are better than those accomplished with alternative conduits and approach the patency rates reported with autogenous saphenous vein. Expanded microporous polytetrafluoroethylene with its high patency, pliability, and tissue incorporation is an excellent arterial substitute. Only with continued use of this material and a more uniform patient selection can more equitable comparisons be made between expanded PTFE and the autogenous vein.

Adult↗
PubMed1978

Serum gastrin levels in the differential diagnosis of recurrent peptic ulceration due to retained gastric antrum.

If recurrent peptic ulceration follows partial gastrectomy with Billroth II reconstruction, retained antrum on the duodenal stump may be the culprit. Moderate hypergastrinemia and a high basal acid output (BAO) to maximal acid output (MAO) ratio on gastric analysis should alert the clinician. Careful filling of the afferent loop on barium meal or technetium 99m scanning may verify the diagnosis. The secretin provocative test may be helpful in distinguishing retained antrum from the Zollinger-Ellison syndrome by eliciting a decrease in serum gastrin levels in patients with retained antrum and an increase in serum gastrin levels in patients with Zollinger-Ellison syndrome.

Aged↗
PubMed1978

Experimental retained antrum. Diagnostic technics and histopathologic correlations.

Retained gastric antrum was evaluated in six dogs, and diagnostic methods correlated with histopathology. Secretin and calcium infusion did not significantly alter circulating gastrin levels. 99 mTc scanning was uniformly positive and did not depend on the presence of parietal cells. The failure to consistently develop hypergastrinemia and the absence of gastrin cell hyperplasia suggest that factors other than gastrin may be implicated in the recurrent ulceration seen with retained antrum.

Animals↗
PubMed1978

Gastric carcinoma following operation for peptic ulcer disease.

Gastric carcinoma following operation for benign peptic ulcer disease has been considered rare but nine patients have been seen during the past five years. All were male patients, the average time interval from prior ulcer operation to development of cancer was 17 years, but was a short as ten years. The symptoms of cancer are vague and the diagnosis is often delayed. Fiberoptic endoscopy with biopsy of suspicious areas is the most accurate diagnostic approach. Resection of the tumor is indicated if feasible. The poor prognosis of this malignancy is documented. The evidence is reviewed that the creation of achlorhydria with bile reflux increases the risk of development of gastric carcinoma. All patients who undergo peptic ulcer operation require careful long-term follow-up. Vague gastrointestinal symptoms occurring ten years or more after peptic ulcer operation require full evaluation to exclude the presence of gastric cancer.

Achlorhydria↗
PubMed1977

Prevention of hypocalcemia by administration of homologous plasma during experimental hemorrhagic pancreatitis in the pig.

Pancreatitis was induced in fifteen immature pigs while five additional pigs underwent sham laparotomy. Animals with pancreatitis were separated into three groups of five each with respect to fluids administered after pancreatitis was induced. Each pig in group A and the control group received normal saline, 300 ml/hour for 8 hours. Pigs in group B received pig plasma at 150 ml/hour plus normal saline at 150 ml/hour for 8 hours. Pigs in group C received pig plasma at 50 ml/hour plus normal saline at 50 ml/hour for 24 hours. Values for serum hematocrit total protein, and total calcium, were measured preoperatively and 4, 8, and 24 hours postoperatively. Control animals and group B animals experienced no change in any parameter. Group A, animals sustained transient severe hemoconcentration, permanent severe hypoproteinemia, and hypocalcemia. Group C animals displayed a transient moderate hemoconcentration and a moderate but sustained decrease in calcium concentration. It is concuded that the hypocalcemia occurring during experimental hemorrhagic pancreatitis is directly related to the early hypovolemia and can be prevented by preventing the hypovolemia.

Animals↗
PubMed1977

The behavior of infected arterial prostheses of expanded polytetrafluoroethylene (Gore-Tex).

In 11 dogs the bacteriologic and morphologic reaction of arterial prostheses made of expanded polytetrafluoroethylene (Gore-Tex) to an induced Staphylococcus aureus septicemia at time of graft implantation was evaluated and compared to that observed with Dacron grafts in 10 dogs. Graft infection developed in all dogs, manifested by positive blood and graft cultures. Grafts, however, could be clearly classified as either histologically infected or uninfected with a marked difference in the pattern of positive blood cultures. Histologically uninfected grafts in general demonstrated the tissue ingrowth and neointima formation which characterize Gore-Tex despite positive graft culture. The appearance of overt histologic infection was correlated with failure of a neointima to develop. Gore-Tex did not loose its structural integrity despite frank injection. The use of the Gore-Tex in the face of overt infection cannot be supported.

Animals↗