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

In contrast to type A aortic dissection, the indication for acute surgical repair as treatment of choice in type B aortic dissection is not the actual dissection, but the complications resulting from the dissection (rupture, potential rupture and ischemic syndromes of the aortic branches). Between 1978 and 1994, 92 patients underwent surgical repair of type B aortic dissection at our institution. Following diagnostic confirmation by echocardiography and/or CT scan, all patients received conservative antihypertensive therapy. 52% of the patients underwent emergency surgical repair. Symptoms prompting surgical repair were: visceral ischemia (23%), pleural effusion (19%), paraparesis (17%), refractory hypertension (12%), further aortic enlargement (12%), and rupture (10%). In chronic type B aortic dissection, the main symptom in 84% of the cases was further enlargement of the aorta. The early mortality decreased in the course of initial treatment from 33% to 16%, and to 8% after exclusion of patients operated on for ruptured aorta. Improved early mortality has led to an increase in acute surgical repair. In cases of chronic dissection, strict antihypertensive therapy is indicated and regular checks on the width of the aorta, as well expeditious diagnostic confirmation of its enlargement, are important.
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PMID:[Early results in the surgical treatment of type B aortic dissection]. 915 26

From January 1991 to May 1994, we have operated on 15 cases of Type B aortic dissection. In 10 of these patients, thoracoabdominal repair was performed. According to Crawford's classification, 2 patients fell into Type I, 6 patients into Type II, and 2 patients into Type III. The aneurysms were exposed through a left thoracotomy extending into the retroperitoneum with the hemidiaphragm divided circumferentially. The operations were performed under femoro-femoral partial cardiopulmonary bypass. In 6 of these cases selective perfusion of the visceral branches was used. The celiac axis was reconstructed in 10 patients, superior mesenteric artery in 9, right renal artery in 7, left renal artery in 6. Abdominal vessels were reconstructed by the "inclusion" technique described by Crawford in 2 patients, by "beveling" the distal prosthetic end in 6 and by the "interposition" technique in 4 patients. Vessels arising from the false lumen were reconstructed by the "interposition" technique. To prevent paraplegia, the evoked spinal cord potentials by direct stimulation of the cord (ESPs-dsc) were monitored perioperatively and the aneurysms were repaired sequentially in segments. In all patients except 2 with Crawford type III aneurysms, spinal cord ischemia was detected by ESPs-dsc. In 7 of these patients, 2 to 8 pairs of intercostal/lumbar arteries (I/L aa.) that arose from the "responsible" aortic segment were reconstructed. Reconstruction techniques included the "inclusion" technique in 2 patients, the "beveling" technique in 1, the "interposition" technique in 1 and the "on lay grafting" technique in 3 patients. One hospital death occurred in a patient who had chronic renal insufficiency and liver cirrhosis preoperatively. Spinal cord injury occurred in 5 patients, including 4 paraparesis and 1 delayed-onset paraplegia. In 2 of these patients, responsible I/L aa., were not reconstructed correctly despite ESPs changes, and injury might have been prevented if reconstruction of the "responsible" arteries had been performed. Thoracoabdominal repair for chronic Type B aortic dissection could be performed safely with an acceptable mortality rate. Spinal cord injury remains an unsolved problem.
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PMID:Operative results of thoracoabdominal repair for chronic type B aortic dissection. 920 Nov 25

Paraplegia is a severe and disastrous complication of operations on the thoracic aorta. For preventing this complication, we employed evoked spinal cord potentials elicited by direct stimulation of the cord (ESPs-dsc) during operations on 83 patients with various aortic lesions (37 dissecting and 46 cases of nondissecting aneurysms, 35 descending and 48 thoracoabdominal aortic aneurysms). All of the patients had some form of circulatory adjunct during aortic cross-clamping. Of the 83 patients, three had "immediate" paraparesis and five had "immediate" paraplegia, whereas three other patients had "delayed" paraplegia. During operation, four types of ESPs-dsc response pattern were observed: (1) no change (n = 57), (2) change with return (n = 15), (3) change with inconsistent return (n = 6), (4) change without return (n = 5). "Delayed" paraplegia occurred in two patients with "no change" and "change with return" response (3%), "immediate" paralysis occurred in three and "delayed" paraplegia occurred in one of those with "change with inconsistent return" response (67%), and all of those with "change with inconsistent return" response (67%), and all of those with "change without return" response developed "immediate" paraplegia (100%). We conclude that intraoperative monitoring of spinal cord function utilizing ESPs-dsc is a good indicator of spinal cord ischemia and we can improve the outcome according to its changes.
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PMID:The reliability of evoked spinal cord potentials elicited by direct stimulation of the cord as a monitor of spinal cord ischemia during temporary occlusion of the thoracic aorta. 923 Jun 15

The major cause of spinal cord injury, during and after aortic surgery, is based on the occurrence of one or more of the three following events: (1) the duration and degree of ischemia;(2) failure to re-establish blood flow to the spinal cord after the repair; and (3) a biochemically mediated reperfusion injury. Clinically, this manifests either as permanent or reversible paraplegia or paraparesis, or a neurogenic bladder. For more than 40 years, numerous methods have been attempted to prevent paralysis, and some of the newer technical innovations include reducing the duration of ischemia, the use of newer centrifugal pump distal perfusion techniques, localized hypothermia, intrathecal maneuvers, pharmacological agents, angiography, somatosensory-evoked potential monitoring, spinal motor-evoked potential monitoring, hydrogen mapping, not resecting the posterior aortic wall, the use of stents, and a spectrum of various pharmacological agents to prevent reperfusion injury to the spinal cord. Some of these techniques and agent seem to be effective at reducing the risk of spinal cord injury.
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PMID:New and future approaches for spinal cord protection. 926 40

We examined the characteristics of neuronal death induced by ischemia in the spinal cord. Spinal cord ischemia was induced in Long-Evans rats by occlusion of the descending aorta with a 2F Fogarty catheter for 20 min (model 1) or more limited aortic occlusion (15 min) coupled with blood volume reduction (model 2); rats were sacrificed 6 h-7 days later. The animals developed variable paraparesis in model 1 and reliable paraplegia in model 2. The extent of histopathological spinal cord damage, being maximal in the lumbar cord, correlated well with the severity of paraparesis. Two distinct types of spinal cord neuronal death were observed, consistent with necrosis and apoptosis. Neuronal necrosis was seen in gray matter laminae 3-7, characterized by the rapid (6 h) onset of eosinophilia on hematoxylin/eosin-stained sections, and gradual (1-7 days) development of eosinophilic ghosting. Although TUNEL positivity was present, disintegration of membranes and cytoplasmic organelles was seen under electron microscopy. Neuronal apoptosis was seen after 1-2 days in dorsal horn laminae 1-3, characterized by both TUNEL positivity and electron microscopic appearance of nuclear chromatin aggregation and the formation of apoptotic bodies. DNA extracted from the ischemic lumbar cord showed internucleosomal fragmentation (laddering) on gel electrophoresis. These data suggest that distinct spinal cord neuronal populations may undergo necrosis and apoptosis following transient ischemic insults.
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PMID:Neuronal apoptosis and necrosis following spinal cord ischemia in the rat. 941 26

Paraplegia, resulting from spinal cord ischemia during thoracoabdominal aortic aneurysm (TAA) repair, continues to be a devastating complication. The incidence of neurological complications, including paraplegia and paraparesis following TAA repair, ranges from 4% to 32% and averages 13% for nondissecting TAA and higher for dissecting TAA. Our current understanding of spinal cord ischemia associated with TAA repair has evolved from animal research and clinical experience. The pathophysiology of spinal cord ischemia is intricately related to three physiological variables. These include the severity and duration of spinal cord ischemia, neuronal reperfusion after reestablishment of spinal cord blood flow, and the neuronal metabolic rate during the ischemic insult. We have developed a multimodality approach to the prevention of neurological deficits, during and after TAA repair, which includes minimizing the severity of spinal cord ischemia, reducing the anticipated reperfusion phenomenon, and lowering the spinal cord metabolic rate. Over the past 16 years, the senior author has undertaken surgical repair of 265 TAAs using a multimodality approach in the protection of spinal cord integrity. In our experience, a combination of adjunctive therapies is critical to minimize the ischemic interval, reduce the neuronal reperfusion injury, and decrease spinal cord metabolism. These techniques have evolved over time, resulting in an overall neurological deficit rate of 4.5% and a neurological deficit at the time of hospital discharge of 1.9%. This article will outline our multimodality approach for spinal cord protection during TAA repair.
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PMID:Adjunctive therapy for spinal cord protection during thoracoabdominal aortic aneurysm repair. 946 76

During aneurysm repair of the descending thoracic or thoracoabdominal aorta, the likelihood of neurological complications increases greatly after only 30 minutes of spinal cord ischemia. However, the manifestation of paraplegia or paraparesis relates not only to aortic cross-clamping time, but to multiple factors that may include aortic dissection, previous aortic surgery, advanced age, preoperative renal insufficiency, rupture, and most significantly, aneurysm extent. At greatest risk is the patient with type II thoracoabdominal aortic aneurysm. For this patient the simple cross-clamp technique, which uses no protective surgical adjuncts, heightens the threat of neurological deficit. With the surgical adjuncts of cerebrospinal fluid drainage and distal aortic perfusion, the probability of neurological deficit is appreciably lowered.
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PMID:Spinal cord protection in descending thoracic and thoracoabdominal aortic aneurysm repair. 946 77

Mild hypothermia and the 21-aminosteroids have both been neuroprotective in several models of cerebral ischemia. In this study we compared the effects of mild hypothermia and the 21-aminosteroid U-74389G, alone and in combination on neurologic and histopathologic outcome after temporary spinal cord ischemia. Forty male anesthetized New Zealand white rabbits were randomized to four groups (n = 10): (a) normothermia (control); (b) U-74389G (3 mg/kg intravenously [i.v.] before aortic occlusion, 1.5 mg/kg i.v. and 10 mg/kg intraperitoneally after occlusion); (c) mild hypothermia (4 degrees C epidural temperature decrease); and (d) mild hypothermia combined with U-74389G. Spinal cord ischemia was produced by 40 min of infrarenal aortic balloon occlusion. Forty-eight hours after the procedure, the neurologic status of the animals was assessed (Tarlov score) and the animals were killed for histologic evaluation. In the normothermic control group, eight of 10 animals became paraplegic. There was a significant reduction of the incidence of paraplegia and overall neurologic deficits and a significant improved Tarlov score in the mild hypothermic group (one animal paraplegic) and in the group with both mild hypothermia and U-74389G (two animals with a mild paraparesis). The histopathologic scores showed significantly less damage in both hypothermic groups. In group 2, U-74389G administration did not improve neurologic or histopathologic outcomes. The results of the current study demonstrate that a slight decrease of intraischemic spinal cord temperature significantly improved neurologic and histopathologic outcomes after experimental spinal cord ischemia. Protection by the 21-aminosteroid at normothermic conditions, or additional protection when U-74389G was added to mild hypothermia, could not be demonstrated.
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PMID:Effect of mild hypothermia and the 21-aminosteroid U-74389G on neurologic and histopathologic outcome after transient spinal cord ischemia in the rabbit. 955 66

A seventy one year-old woman, who had an arch and thoracoabdominal aortic aneurysm (type II according to Crawford classification) with ischemic heart disease, underwent a separate operation using the elephant trunk method. At first, she underwent the ascending aorta and arch replacement the with elephant trunk technique, and, underwent CABG simulutaneously utilizing the separate extra corporeal circulation and hypothermic circulatory arrest. The Chest and abdominal CT revealed the enlargement of abdominal aortic aneurysm 5 months after operation. The second operation was performed using Stoney's spiral opening method and the revasculization of spinal arteries (Th6, 7 and Th9) underwent the segmental aortic clamping to prevent spinal cord ischemia. Furthermore, the second operation was performed using selective perfusion to visceral arteries and F-F bypass for the prevention of visceral ischemia. Each flow rate by selective perfusion in major abdominal blanches was from 50 to 100 ml/min. Therefore, hepatorenal dysfunction and paraparesis did not occur after the second operation. It was suggested that the segmental aortic clamping and the selective perfusion to visceral arteries with F-F bypass may be effective to prevent the ischemia of the spinal cord and abdominal organs.
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PMID:[Separate operation for extensive aneurysm (mega-aorta) complicated with ischemic heart disease]. 978 73

We report the case of a 66-year-old man who had a descending thoracic aneurysm, diagnosed as aortitis syndrome. He subsequently underwent an aneurysmectomy under simultaneous sensory and motor spinal cord monitoring. Spinal cord ischemia was diagnosed during prosthetic replacement of the aneurysm by changes in evoked spinal cord potentials and motor evoked potentials from the lumbar spinal cord enlargement and 2 pairs of intercostal arteries were reconstructed at the level of T9 and 10. After surgery, the patient developed paraparesis below T10, but the resulting neurological deficits were overcome with postoperative rehabilitation. Simultaneous monitoring of evoked spinal cord potentials and motor evoked potentials were useful in evaluating spinal cord ischemia during aortic aneurysm surgery and in determing whether intercostal arteries should be reconstructed.
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PMID:Three different approaches to spinal cord monitoring for the prediction of spinal cord ischemia during thoracic aortic aneurysm surgery. 982 91


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