Biomedical subjects

A R Downs

Publications and source records attributed to A R Downs.

At least 19 recordsLinked to original sources

PubMed1991

Internal jugular vein reconstruction using a superficial femoral vein graft.

Numerous methods of venous reconstruction have been described to help prevent the many complications related to bilateral ligation of the internal jugular veins. The authors report a case in which the superficial femoral vein was used as the donor graft for reconstruction of the internal jugular vein in a 61-year-old man who underwent a tonsillar commando procedure for cancer. The advantages of using this donor vein for reconstruction of the internal jugular vein are summarized.

Carcinoma, Squamous Cell↗

PubMed1991

Etiology of prosthetic anastomotic false aneurysms: pathologic and structural evaluation in 26 cases.

To determine the etiology of anastomotic false aneurysms (AFAs), 26 textile graft specimens, removed because of AFA, were studied morphologically, histologically and by scanning electron microscopy. No cases of suture-related failures leading to AFA were found. Nine cases of frayed grafts were documented but were not the cause of AFA formation. In three cases, chemical degradation of the fibres, which may have been secondary to lipid infiltration, may have contributed to AFA formation. There were no cases of overt clinical infection, but the presence of bacteria was documented by scanning electron microscopy in 20 cases. The role of bacteria is not well defined, but they may be a factor in host arterial-wall degeneration as a cause for AFA formation.

Adult↗

PubMed1989

Measurement of extravascular lung water during abdominal aortic surgery.

Cross-clamping of the abdominal aorta can be associated with significant changes in haemodynamic variables. However, intraoperative changes in extravascular lung water (EVLW) have not been studied. Nine patients undergoing elective surgery, either aortic aneurysm repair or aorto-bifemoral grafting, were monitored invasively with arterial lines, pulmonary artery catheters and Edwards lung water catheters inserted in either the brachial or axillary artery. Determinations of EVLW were made prior to and five minutes after application of the aortic cross-clamp and at 30-minute intervals during the course of the operation. Baseline EVLW was found to be 7-9 ml.kg-1. There were no significant changes in haemodynamic variables and no changes in EVLW with cross-clamping of the aorta. The EVLW did not change during the course of surgery. The EVLW did not increase in the absence of sustained elevation of pulmonary capillary wedge pressure. One patient developed an axillary artery thrombosis which required thrombectomy at the site of lung water catheter insertion. Two other patients lost their distal pulses without overt ischaemic changes. It was felt that such relatively high incidence of complications precluded further use of the lung water catheter in the axillary or brachial artery.

Adult↗

PubMed1988

Hemorrhage and pelvic fractures.

Hemorrhage is the major cause of death in pelvic fractures. In closed pelvic fractures the bleeding is usually self-limited. In the small number of patients with continuing hemorrhage there may be disruption of a major iliac vessel, which will require immediate exploration and repair. In a few patients continuing hemorrhage is due to disruption of a branch of the hypogastric artery, which may be identified by angiography and controlled by embolization. A management protocol is suggested for these patients.

Angiography↗

PubMed1987

The value of combined pulsed-Doppler and high-resolution real-time sonography of the extracranial carotid system.

Duplex carotid sonography (DCS) (high-resolution real-time with combined pulsed Doppler) was performed in 374 symptomatic patients. Biplane angiographic correlation was available in 172 extracranial carotid systems. Degree of stenosis was estimated by the Doppler spectrum and by real-time appearances and categorized as: normal; less than 10% diameter reduction; 10-49% diameter reduction; 50-99% diameter reduction; or occlusion. The overall accuracy of sonography was 88%. Normal arteries were identified with a specificity of 96% and a positive predictive value of 97%. Hemodynamically, significant lesions were differentiated from less severe disease with an accuracy of 95%, a positive predictive value of 87%, and a negative predictive value of 100%. Occlusions were identified with a sensitivity of 80% and a positive value of 91%. Duplex sonography is an accurate, noninvasive method of evaluating the extracranial carotid system.

Angiography↗

PubMed1987

Peripheral nerve injuries during carotid endarterectomy.

Peripheral nerve injuries associated with carotid endarterectomy are fairly common but not emphasized in reported results of carotid endarterectomy. The sensory nerves to the submandibular skin and ear lobe are often damaged. Motor nerves VII, IX, X, XI and XII may be injured at surgery. The commonest motor injuries involve the facial, vagus and hypoglossal nerves. Carotid endarterectomy was studied prospectively over 1 year to document the incidence of nerve injury. Nerve injury occurred in 12% of patients, with facial and vagus nerves being involved in 4% each. Careful surgical technique based on appropriate anatomical knowledge can prevent most of these complications.

Carotid Arteries↗

PubMed1986

Anastomotic false aneurysms with aortic Dacron graft after twenty-five years.

One of the early diamond crimped knitted polyester (Dacron) grafts was surgically excised after implantation for 25 years in the aorto-biiliac position because of false aneurysm formation at the three anastomotic sites. The sutures were no longer visible. While the areas around the false aneurysm were poorly incorporated, the graft limbs were well encapsulated with some endothelial-like cells on the luminal surface. The integrity of the graft was well preserved despite mild fraying and the disruption of one stitch.

Adult↗

PubMed1986

Popliteal artery injuries: civilian experience with sixty-three patients during a twenty-four year period (1960 through 1984).

Our experience with 63 patients who had popliteal artery injuries sustained in civilian accidents is reported. Blunt injuries occurred in 53 patients and 49 had associated skeletal injuries. Eighteen patients suffered knee dislocation; six of these patients had associated fractures. Fractures of the upper third of the tibia occurred in 21 patients. Five patients had irreversible ischemia and required primary amputation. Thirteen amputations were required in 58 patients in whom arterial repair was performed, for an amputation rate of 22%. There were no amputations in 19 patients treated less than 6 hours after injury was sustained. Four deaths occurred. Fasciotomy was performed in 20 patients. Skeletal injuries were usually treated with external fixation.

Adolescent↗

PubMed1986

Occlusion of the aortofemoral prosthetic graft.

The commonest late complication of aortofemoral prosthetic grafting is graft-limb occlusion, the usual cause of which is outflow obstruction due to anastomotic neointimal hyperplasia or progressive atherosclerosis in the deep femoral artery. Occasionally graft-limb occlusion is due to thrombosis of an anastomotic false aneurysm or is associated with graft infection. Inflow occlusion at the aortic anastomosis is uncommon unless the aortic anastomosis is at the lower end of the aorta distal to the inferior mesenteric artery. When graft-limb occlusion occurs, severe ischemia usually necessitates urgent revascularization to save the leg. Graft thrombectomy and profundaplasty may be successful; however, a cross-femoral graft to the distal patent deep femoral artery is probably the simplest procedure and is usually effective. Occasionally a distal femoropopliteal reconstruction is necessary to establish a satisfactory outflow. Unsuccessful reconstruction of a graft-limb occlusion usually necessitates a high, above-knee amputation.

Aorta, Abdominal↗

PubMed1986

The virgin, modified, human, umbilical vein graft: morphologic characteristics and mechanical properties.

The authors used macrophotography, endoscopy, roentgenography, light microscopy, and transmission and scanning electron microscopy to assess the morphologic characteristics of 37 virgin, human, umbilical vein grafts. The specimens showed deep longitudinal folds (22%) and multiple transverse folds of the intimal surface (27%), irregularity of wall thickness (41%) and intimal breakdown exposing thrombogenic layers of the vein wall to blood (19%). The mechanical properties also studied were dynamic compliance, Young's modulus, breaking strength and breaking strain. The mean dynamic compliance was 6.44 X 10(-4) mm Hg-1 (SD = 2.02 X 10(-4) mm Hg-1, i.e., 31%), which is in agreement with results of others. The specimens showed great variability in Young's modulus, breaking strength and breaking strain. The structural deficiencies and variable mechanical properties of human umbilical vein grafts require investigation to determine their effect on patency rates due to increased thrombogenicity and thus to establish whether there are potential hazards associated with their use.

Biomechanical Phenomena↗

PubMed1986

Inflammatory abdominal aortic aneurysm.

The inflammatory abdominal aortic aneurysm has received little attention in the literature. To date only four reports have addressed the subject specifically. Controversy remains as to whether this is a variant of the usual atherosclerotic aneurysm or a separate entity. The operative reports of 24 patients with inflammatory abdominal aortic aneurysms are reviewed; 21 were intact and 3 ruptured. Intact aneurysms ranged in diameter from 5 to 12 cm and the ruptured ones from 5 to 10 cm. Nine patients with intact aneurysms had symptoms of abdominal or back pain. Of 13 patients who underwent excretory pyelography before operation, only 3 had evidence of obstruction. Nine patients had tube grafts placed, 10 had aortoiliac grafts and 5 aortofemoral grafts. There was one intraoperative duodenal injury and in another patient it was necessary to divide the left renal vein for proximal exposure. No attempt was made to expose the ureters at operation. All patients were discharged from hospital. The authors believe that the inflammatory aneurysm is a variant of the abdominal aortic arteriosclerotic aneurysm. Intraoperative complications can be avoided by the recognition of the pathological features.

Aged↗

PubMed1986

White clot syndrome: a rare complication of heparin therapy.

A case of white clot syndrome in a 61-year-old man is reported. The patient suffered simultaneous aortic and vena caval thromboses while receiving heparin therapy for pulmonary embolism. Thrombocytopenia was noted. Thrombectomies successfully relieved the thromboses. Apart from heparin, no factors predisposing to aortic thrombosis were evident, and the patient remained well in the succeeding 7 years since. A brief review of the literature on the white clot syndrome suggests that the entity remains poorly defined, regarding both the mechanism of heparin-induced thrombocytopenia and its relation to thrombosis.

Aorta, Abdominal↗

PubMed1983

Graft infections in aortoiliac arterial reconstructions.

Twenty-four patients with 25 infected prosthetic grafts have been treated at the Health Sciences Centre in Winnipeg over the past 20 years. Nineteen primary operations were done for aortoiliac occlusive disease and 6 for abdominal aortic aneurysms. The patients presented from 2 weeks to 9 years after the first operation. In 16 of the graft infections there was a groin abscess, a draining sinus or a false aneurysm. The commonest method of treatment was excision of the entire graft with immediate extra-anatomic arterial reconstruction. Six patients died. Early diagnosis and aggressive surgical treatment are emphasized.

Aorta↗

PubMed1982

General surgery.

Explore the source record for details and available documents.

Education, Medical↗

PubMed1982

Carotid artery spasm. A cause of postendarterectomy thrombosis?

Carotid endarterectomy is generally regarded as a durable repair, with a low incidence of postoperative thrombosis. However, unexpected, inexplicable occlusions and pressure-flow aberrations have been reported to occur during the period immediately after operation period. We studied 245 operative angiograms obtained during a series of 335 carotid endarterectomies. Among the various defects noted were 24 instances of mild to severe spasm of the middle and distal extracranial carotid artery. This spasm was remote from the endarterectomy site and often was entirely beyond the field of operative exposure. Early and late postoperative angiograms demonstrated that this may be a transient phenomenon, and repeated intraoperative films documented that spasm may progress without further direct instrumentation of the involved segment. The patient who demonstrated the most severe spasm later suffered immediate postoperative occlusion and stroke despite a technically satisfactory repair.

Carotid Artery Diseases↗

PubMed1982

Vascular injuries of the limbs.

Seven different kinds of arterial injury may occur to the limb. These may be accompanied by external bleeding and may result in ischemia sufficient to put the limb in jeopardy. There may be contusion of the arterial wall and thrombosis. There may be true or false aneurysms and arteriovenous fistulas. The extent and location of the injury must be ascertained early. The artery should be conservatively debrided and repaired by end-to-end anastomosis, interpositional grafting or bypass grafting. When possible, skeletal injuries should be stabilized by external fixation. Nerve injuries should be marked for later repair. Antibiotics should be used prophylactically. Mannitol may be used for diuresis. Amputation may be indicated. Fasciotomy is carried out in the presence of compartment compression.

Adult↗

PubMed1982

Aortoiliac reconstruction for occlusive disease: comparison of end-to-end and end-to-side proximal anastomoses.

Between 1968 and 1979, 192 aortofemoral bifurcation grafts were placed for aortoiliac occlusive disease. The proximal anastomosis was end-to-end in 101 and end-to-side in 91 patients. Anastomoses were end-to-end in 38 (37%) of 104 patients from 1968 to 1976 and 63 (72%) of 88 patients from 1977 to 1979. Embolization occurred intraoperatively in four end-to-end and five end-to-side anastomoses. The grafts became occluded in the early postoperative period in two patients with end-to-end proximal anastomoses. There were two aortoduodenal fistulas, both associated with end-to-side proximal anastomosis. The cumulative patency rate at 5 years was 87% for end-to-end and 85% for end-to-side anastomoses. An end-to-end proximal anastomosis is indicated for associated aneurysmal disease or in the presence of aortic occlusion, while an end-to-side anastomosis is indicated when there are low-lying accessory renal arteries or in the presence of occlusive disease in the external iliac arteries. The author's experience suggests that there is no difference in the incidence of intraoperative embolization or late occlusion between end-to-side and end-to-end proximal anastomosis. The incidence of aortoduodenal fistula appears to be lower with end-to-end proximal anastomosis possibly because of better tissue apposition at the anastomosis.

Aorta↗

PubMed1981

Acute renal failure as a consequence of sudden renal artery occlusion.

Acute renal failure secondary to renal artery occlusion is rare but can be reversed and is therefore important to cases to draw attention to the diagnosis and management of the condition. In one case, occlusion of the artery to a single functioning kidney was responsible for the clinical presentation; in the other, bilateral renal artery emboli were responsible. The authors present a detailed review of the English literature to determine the prognostic value of the duration of anuria preceding operation in patients with renal artery occlusion to a solitary kidney. This factor showed no correction with viability of renal tissue, functional recovery or patient survival. Surgical management offers the best prospect of success in these patients.

Acute Disease↗