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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Surgical management of the thoracoabdominal aortic aneurysm is a formidable undertaking. Presently two fairly distinct operative methods are available. The conventional technique, pioneered by Etheredge, involves replacement of the aneurysm with a synthetic graft and then, step by step, revascularization of the abdominal organs with prosthetic side limbs taken from the primary graft. Individual organ ischemic time is limited to that time required for the performance of each distal side limb anastomosis. The second operative method, first described by Crawford, consists of proximal and distal control of the aneurysm, followed by its incision to simultaneously expose the origin of all four major intra-abdominal arteries. Replacement is then rapidly performed with a tubular Dacron graft including anastomosis of these major intra-abdominal arteries to four elliptical graft incisions, from within the aneurysm. Total operating time is reduced at the expense of prolonged organ ischemia. The conventional method allows for step-by-step intraoperative planning and action, and this technique is accordingly recommended to most surgeons, who have had little experience with this unusual lesion. Our recent successful experience with two cases of extensive thoracoabdominal aortic aneurysms is described as well as a discussion of additional measures which may become useful in certain cases to favor a successful outcome. Finally the problem of potential resultant paraplegia is discussed.
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PMID:Thoracoabdominal aortic aneurysms. A review and current status. 15 75

Infected aneurysms involve the aorta, visceral and peripheral arteries and are associated with a high morbidity and mortality. Prompt confirmation of the suspicion of infection, resection of all infected tissue, and prolonged antibiotic therapy based on appropriate sensitivity studies are crucial to successful management. Patients whose aortic aneurysms grew Gram negative organisms were more likely to suffer early rupture of an aortic aneurysm, and had a higher mortality. Superior mesenteric aneurysms are preferably treated by resection. Upper extremity aneurysms can often be excised without distal ischemia. Lower extremity aneurysms were more likely to require reconstruction which can be accomplished through non-infected tissue planes, preferably with autogenous tissue.
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PMID:The management of infected arterial aneurysms. 57 24

Eight cases of mycotic aneurysm occurred in seven transplant patients. Perinephric wound infection involving the iliac arteries was the cause of at least seven aneurysms. Simple ligation of the iliac artery proximal and distal to the aneurysm without grafting was effective therapy in all but one patient with an aortic aneurysm who required an axillofemoral bypass graft prior to excision of the aneurysm. There were no instances of ischemia to the involved extremities, and only two patients died as a result of the aneurysm. This dangerous complication can be avoided by preventing wound infections. In established perinephric abscesses, the kidney should be removed and the wound kept as clean as possible in order to prevent this complication. Arteriograms may be useful in the early detection of these aneurysms, before they rupture.
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PMID:Mycotic aneurysms in transplant patients. 76 50

Neurological complications of dissecting aneurysm of the aorta are not frequently described in the literature. A case of infarction of the spinal cord secondary to aortic aneurysm is presented. The ischemic zone extended from D5-D6 to L2-L3, showing the typical double-funnel-like configuration. Such localization is explained by the blood circulation in the spinal cord. The rupture of a dissecting aortic aneurysm in the toracic and abdominal tract, by occluding the segmental branches to the spinal cord, causes a decrease in blood flow which is responsible for the neurological manifestations. In the present case ischemia is mainly due to the involvement of the artery of Adamkiewicz, while the relative sparing found at the inferior lumbar level is justified by the existence of vessels which take origin below the aneurysm and are tributary to the cauda equina. The histological findings are in agreement with previous observations of a selective necrosis of the gray matter.
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PMID:[Anatomo clinical aspects of a case of ischaemic necrosis of the spinal cord in a patient with a dissecting aneurysm of the aorta (author's transl)]. 85 84

A 15-year experience with 92 subcutaneous arterial bypass grafts for lower extremity revascularization has been reviewed. Fifty-nine AF and 33 FF bypass operations were performed on 89 patients whose average age was 66 years. The overall five-year survival was 33% compared to an expected survival of 80%. 88% of the AF, and 76% of the FF operations were performed for limb salvage, bypass of an aortic aneurysm, or replacement of an infected aortic graft. The remainder were performed for intermittent claudication on patients who were too ill to withstand an intra-abdominal operation. 75% of the patients with AF grafts and 64% of those with FF grafts experienced complete relief of lower extremity ischemia, including all of the patients with claudication. Graft patency was analyzed by the life table method. In the FF series, 74% of the grafts remained patent for one year; 73% for two years; 66% for three years; and 53% for four years. A 50% incidence of thrombosis occurred at the end of two years in the AF group. The patency rate of the AF grafts was also studied with regard to the type of graft material employed: a 50% incidence of thrombosis was reached at 36 months with knitted Dacron; at 18 months with weave-knit Dacron; and at 9 months with woven Dacron. THESE DATA INDICATE THAT: (1) contrary to our previous report, weave-grafts provide adequate blood flow to the lower extremities but do not remain patent as long as more conventional types of reconstruction; (2) subcutaneous grafts should be performed only when an intra-abdominal procedure is contraindicated or life expectancy is limited.
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PMID:Fifteen year experience with subcutaneous bypass grafts for lower extremity ischemia. 88 58

We reviewed the incidence of neurologic complications in 200 consecutive patients with aortic aneurysm or aortic dissection. In this 2-year period, neurologic impairment developed in 18.5% of these patients, and in 10 patients neurologic dysfunction heralded aortic rupture or dissection. Those patients with abnormal neurologic examinations at presentation frequently had aneurysm rupture or dissection and a mortality rate of 54%. Patients with thoracic or thoracoabdominal aneurysms were more likely to have neurologic complications than those with abdominal aneurysms. The most common complications were focal central nervous system ischemia, followed by disorders of consciousness and peripheral nerve complications. In patients who had elective aneurysm resection, female sex, aneurysm location, and intraoperative hypotension were risk factors for focal central nervous system ischemia. We conclude that neurologic complications depend on aneurysmal location, occur at various levels of the nervous system, and frequently develop when the intraoperative mean arterial pressure falls below 55 mm Hg.
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PMID:Risk factors for the neurologic complications associated with aortic aneurysms. 131 Nov 68

Visceral ischemia is a serious factor in the postoperative morbidity and mortality of suprarenal aortic reconstruction. We reported two patients of suprarenal aortic aneurysm involving visceral arteries, who received successful Dacron graft replacement by using Pruitt-Inahara balloon catheters as an autoperfusion for preservation of the visceral organs. No visceral organ ischemia occurred postoperatively except in patient 2 who had preoperative chronic renal failure and persistent renal failure after the operation. The renal function recovered gradually during the follow-up period. Both patients are doing well at the present time. The new autoperfusion technique can directly deliver normothermic blood from the arterial cannula at proximal aorta to the individual visceral arteries by using the balloon perfusion catheters. It is simple, safe, easily instituted and the used products are readily obtainable. It allows the surgeon to provide an effective protection of visceral organs for the suprarenal aortic reconstruction.
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PMID:A new autoperfusion technique for aortic reconstruction of suprarenal aortic aneurysm. 132 68

The role of surgical therapy for Takayasu arteritis remains controversial. From 1973-1991, 23 patients with Takayasu arteritis have been treated at the University of Southern California. Twelve patients have required 17 arterial reconstructions for symptomatic complications of arterial disease refractory to medical therapy. Indications for operation have included renovascular hypertension (7), extremity ischemia (5), cerebrovascular insufficiency (2), dilated ascended aorta with aortic insufficiency (1), thoracic aortic aneurysm (1), and abdominal aortic aneurysm (1). Long-term clinical follow-up has demonstrated uniform symptomatic improvement. Fifteen of seventeen arterial reconstructions are still patent. Surgical treatment of symptomatic Takayasu arteritis is highly effective. Excellent long-term graft patency can be expected following arterial reconstruction.
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PMID:Surgical treatment of Takayasu arteritis. 136 Sep 62

The prevalence of morbidity is a major deterrent to the success of aortic aneurysm replacement operations. We have developed a model of spinal cord ischemia, based on the amplitude reduction of the motor-evoked potential, which produces approximately a 90% prevalence of paraplegia. Regional blood flow was studied with the use of radioactive microspheres, and results showed that there was a significant decrease in flow to the lumbar cord (85% reduction) during aortic occlusion, followed by a twofold to threefold hyperemia that persisted for 24 hours. Histopathologic examination of the cord revealed that the greater portion of microgliosis, spongiosis, and neuronal damage was confined to the gray matter of the cord, and its severity increased as one progressed caudally. The somatosensory-evoked potential disappeared before the motor-evoked potential L-2 signal in all dogs, with a mean disappearance time of 10.9 +/- 5.6 minutes, compared with 21 +/- 6.6 minutes for the motor-evoked potential. Both the sensory-evoked potential and the motor-evoked potential cord signal were present 24 hours later in all dogs tested. The peripheral nerve motor-evoked potential disappeared within 1 minute of cord ischemia, was not present 24 hours later, and hence appears to be too sensitive to use as an indicator of spinal cord damage. Plotting spinal cord motor-evoked potential amplitude reduction versus both histopathologic damage and regional blood flow revealed a positive correlation between motor-evoked potential amplitude reduction, decreased cord perfusion, and increased histopathologic damage. In addition, it may be possible to make inferences about the neurologic status of a subject based on the magnitude and time-course of the motor-evoked potential's amplitude reduction and wave morphology.
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PMID:Correlation of motor-evoked potential response to ischemic spinal cord damage. 149 88

Although monitoring of somatosensory evoked potentials elicited from stimulation of lower extremity peripheral nerves has been suggested as a method for assessing neural function during thoracoabdominal aortic aneurysm surgery, this technique has been reported to yield a large number of false positives. It was believed that direct stimulation of the spinal cord would eliminate some of the problems associated with peripheral evoked potentials. The present study compared in 18 patients the use of scalp recorded evoked potential following stimulation of either the posterior tibial nerve via percutaneous needles or the spinal cord via an epidural electrode previously placed fluoroscopically. In 10 patients in whom distal bypass or shunt was not used, peripheral evoked potentials totally disappeared within 5-30 min of aortic clamping. Spinal cord stimulation evoked potentials disappeared permanently in 2 patients shortly after aortic cross-clamping; 1 died shortly after the procedure, and the other awoke densely paraplegic and died the next day. When distal perfusion was maintained by shunt or bypass, the disappearance of both peripheral and spinal evoked potentials accurately predicted the neurologic outcome of 1 paralyzed patient. Loss of spinal cord stimulation evoked potentials was found to be correlated with adverse neurologic outcome. Over the period of aortic clamping a gradual decrease in mean amplitude (50% at 45 min [P less than 0.05]) and a 20% increase in mean latency time were observed. Maintenance of adequate distal perfusion may permit the use of peripheral evoked potentials in the assessment of spinal cord ischemia during aortic cross-clamping.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Spinal cord stimulation evoked potentials during thoracoabdominal aortic aneurysm surgery. 157 35


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