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Biomedical subjects

W F Barker

Publications and source records attributed to W F Barker.

At least 37 records · Page 2Linked to original sources
PubMed1980

Selective management of extracranial carotid arterial aneurysms.

Aneurysms of the extracranial carotid arteries are rare vascular lesions that produce a high incidence of unfavorable neurologic sequelae. In the past 24 years, 19 patients at UCLA Hospital were treated for angiographically demonstrable extracranial carotid arterial aneurysms. These cases were reviewed to determine the natural history of these lesions as influenced by various modes of therapy in order to develop a logical treatment plan for these difficult patients. Because of the varied location of these lesions, proper treatment requires a diversity of techniques. Gratifying results can be achieved when a carefully selected operative approach is undertaken.

Adult↗
PubMed1980

Atrophic coarctation of the abdominal aorta.

Two cases illustrate the clinical manifestations and angiographic findings associated with segmental stenosis of the abdominal aorta. Such lesions represent the chronic occlusive stage of Takayasu's disease, a nonspecific inflammatory arteritis of uncertain etiology. While the disease is considered autoimmune, an infectious process may be involved. Complications typically associated with stenotic lesions of the abdominal aorta are secondary renal hypertension and ischemic symptoms secondary to vascular insufficiency. Surgical correction, the treatment of choice, has achieved excellent results for these well-localized lesions. Secondary renal hypertension was relieved by a spenorenal shunt and the disease has since been controlled with conservative management in the first patient. An aortofemoral bypass graft successfully alleviated the vascular insufficiency in the second patient, although the patient unfortunately expired from a refractory postoperative cardiac complication.

Adolescent↗
PubMed1980

Ocular pneumoplethysmography in the evaluation of carotid stenosis.

Ocular pneumoplethysmography is a noninvasive technique for detecting carotid stenosis by measurement of ophthalmic artery pressure. The results of the test were studied in 227 patients who underwent biplane angiography. The overall accuracy was 93% in the correct identification of hemodynamically significant stenosis (defined as a 60% or greater decrease in luminal diameter). The good result of this single test makes it our choice of noninvasive methods for both screening and follow-up study of carotid occlusive disease.

Carotid Arteries↗
PubMed1979

Late results of extra-anatomic bypass.

Clinical progress and results were reviewed in 100 consecutive patients who underwent extra-anatomic bypass procedures for brachiocephalic and aortoiliac occlusive disease during the past 15 years. Of 113 procedures in this group, extra-anatomic bypass of the brachiocephalic vessels, axillo-femoral bypass, and femorofemoral bypass were performed. Although these procedures were performed in high-risk patients to avoid intrathoracic and intra-abdominal reconstruction or to circumvent undesirable anatomic areas, a low operative mortality was achieved. Symptomatic improvement, augmented Doppler ankle pressure index, and high limb-salvage rate were noted. Life-table analysis has confirmed prolonged five-year graft patency. The suspected high-risk characteristic in this group was corroborated by high progressive mortality observed particularly after axillo-femoral bypass and was due primarily to the severity of associated diseases. Analysis of the late results of extraanatomic bypass confirms the safety and effectiveness of this procedure in poor-risk patients.

Adult↗
PubMed1978

Evaluation of extracranial cerebrovascular disease with ocular pneumoplethysmography.

The results of OPG studies performed on 121 patients between 1974 and 1977 are compared with the results of biplane angiograms. By adding criteria based on the ratio of AOP:BAP, the overall accuracy was increased from 76.9 to 91.7 per cent. This improvement was obtained by establishing criteria that identified bilateral significant lesions. The results have confirmed the value of OPG in noninvasive assessment of carotid artery disease.

Air↗
PubMed1978

A modification in the technique of making the Koch ileostomy pouch.

This minor modification in the original technique assures greater security and permanence of the nipple, yet takes no longer to perform than the original procedure. The steps have been defined in a manner calculated to simplify the technique for the surgeon who is not already familiar with the operation.

Humans↗
PubMed1977

Noninvasive methods for evaluation of extracranial cerebrovascular disease. A comparison.

Sixty-five patients with clinical evidence of carotid occlusive disease were evaluated by the Doppler ophthalamic test, ophthalmodynamography, and oculopneumoplethysmography prior to angiography. Clinical assessment was accurate 68% of the time, with 32% of patients having no arteriographic evidence of significant disease. The sensitivity of the noninvasive tests was dependent on the extent of the carotid stenosis. When the extent was greater than 60% of the cross-sectional diameter, the Doppler ophthalmic test was accurate 54% of the time; the ophthalmodynamography test, 61% of the time; and the oculopneumoplethysmographic test, 97% of the time. In lesions encompassing 50% to 60% of the vessel diameter, the Doppler ophthalmic test was accurate 15% of the time; the ophthalmodynamography test, 17% of the time; and the oculopneumoplethysmographic test, 10% of the time. With less than 50% stenosis, none of the noninvasive tests detected atherosclerotic lesions. Although many diseased vessels were missed, the low incidence of false-positive tests enhanced the usefulness of these methods in augmenting the accuracy of clinical evaluation.

Carotid Artery Diseases↗
PubMed1977

Breast reconstruction after mastectomy.

Reconstruction of the breast contour and areolanipple complex can be undertaken in patients who have had mastectomy for carcinoma of the breast. Although the reconstructed breast is not normal, the restored contour and simulation is gratifying for those patients who have sought this procedure.

Adipose Tissue↗
PubMed1976

Effect of cardiac dysrhythmia on cerebral perfusion.

Extracranial carotid arterial obstructive disease has been the entity most commonly associated with transient cerebrovascular insufficiency. A nonobstructive, frequently overlooked cause of cerebral ischemia is cardiac dysrhythmia. We have explored this by observations of experimental animals and of man. Blood flow and pressure in the carotid arteries of dogs were shown to be decreased by mechnically induced premature ventricular contractions. The significance of the cardiogenic contribution to altered cerebrovascular perfusion was studied by ocular and brachial plethysmography in 210 patients suspected by history of having carotid arterial insufficiency. Of the 210 patients, 62 demonstrated abnormal ocular plethysmographic recordings, and of those, nine had dysrhythmias associated with significant deficits of ocular perfusion. Five patients whose recordings were technically suitable for publication are presented to demonstrate the bizarre ocular plethysmographic recordings seen during the dysrhythmic cycle.

Adult↗
PubMed1975

Ophthalmic arterial blood pressures measured by ocular plethysmodynamography.

The indirect measurement of ophthalmic arterial blood pressure is an important index in the understanding of cerebral vacsular hemodynamics. Ophthalmodynamometry (ODM), the prototype for such measurement, is, however, replete with difficulties that have limited its widespread use. A preliminary evaluation of a new technique for ODM identified as ocular plethysmodynamography, has yielded accurate opthalmic blood pressure data without the attendant problems. Reproducible values for bilateral ophthalmic arterial pressure levels have been determined in 30 normal volunteers and the levels correlated to brachial arterial pressure levels. In a series of patients with arteriographically demonstrable carotid obstructive lesions, the preoperative and postoperative ophthalmic arterial blood pressure relationships exhibited excellent correlation with the roentgenographic and intraoperative data.

Adult↗
PubMed1975

Autogenous vein bypass grafts: biological effects of mechanical dilatation and adventitial stripping in dogs.

To evaluate whether mechanical vein dilatation and stripping of adventitia at the time of harvest may adversely alter the long-term fate of autogenous vein grafts, dogs were subjected to reversed femoral vein interposition grafting with either normal veins, mechanically dilated veins, or adventitially stripped veins. Vein segments taken before grafting and veins exposed in situ but not grafted served as controls. Animals were killed at 3 months, and five vein segments in each category were evaluated for gross and microscopic changes. All grafts subjected to arterial interposition displayed marked neointimal proliferation and fibrosis of the media and adventitia. Notably, both dilated and stripped veins appeared to be similar and were indistinguishable from normal veins that had been subjected to arterial interposition for the same duration. Veins exposed in situ but not subjected to arterial flow remained essentially normal. Adverse alterations attributed to vein dilatation or adventitial stripping were not apparent and should not be invoked in the mechanism of graft failure at 3 months' duration.

Animals↗