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Query: UMLS:C0917798 (cerebral ischemia)
 17,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previously, we demonstrated that cerebral focal ischemic tissue exhibits a significant increase in immunoreactive endothelin (ET). Because increased ET might exacerbate the consequences of cerebral ischemia, we evaluated the effects of the orally active ETA/B receptor antagonist SB 217242 on middle cerebral artery occlusion (MCAO) in the spontaneously hypertensive rat (SHR). SHRs were treated b.i.d. with vehicle or with 3 or 15 mg/kg SB 217242 p.o. for 7 days. Permanent MCAO was performed on day 7 and animals were sacrificed on day 8. Forebrains were stained and the extent of cerebral (i.e., cortical) infarction was determined using image analysis. Hemispheric swelling (%), hemispheric infarct (%), and infarct volume (mm3) were quantitated for each animal. SB 217242 treatment produced a significant decrease in ischemic brain injury. Hemispheric infarction and infarct volume were reduced after the 15 mg/kg treatment (12.0 +/- 1.1% and 69 +/- 6 mm3) compared to vehicle (17.3 +/- 1.5% and 99 +/- 8 mm3) (p < 0.05). No significant effects on hemispheric swelling were observed. This is the first demonstration of an ET receptor antagonist exhibiting efficacy in cerebral focal ischemia. The fact that a 30% reduction in ischemic brain injury can be demonstrated after oral administration of SB 217242 suggests that ET antagonists may be of therapeutic utility in focal stroke.
J Cardiovasc Pharmacol 1995
PMID:The endothelin receptor antagonist SB 217242 reduces cerebral focal ischemic brain injury. 858 28

This investigation demonstrates an increase in endothelin (ET)-mediated vascular tone in peri-ischemic areas after experimental focal cerebral ischemia (middle cerebral artery occlusion) in the cat. Adventitial application of the butenolide antagonist PD155080 (30 microM), after MCA occlusions resulted in marked increases in caliber of dilated (10.6 +/- 1.6% change from preinjection baseline) and constricted vessels (68.7 +/- 17.5% change from pre-injection baseline). Cerebral blood flow (measured by laser Doppler flowmetry) was reduced after MCA occlusion to 50% of preocclusion levels. Intravenous administration of PD156707 30 min after MCA occlusion restored cerebral blood flow to preocclusion baseline levels at 6 h. The volume of ischemic damage in the cerebral hemisphere after MCA occlusion was significantly reduced (by 45%) after intravenous administration of PD156707.
J Cardiovasc Pharmacol 1995
PMID:Therapeutic potential of endothelin receptor antagonists in experimental stroke. 858 30

The surgical mortality among 22 patients treated for thoracic or thoracoabdominal aneurysm was compared with the mortality in 47 patients managed without surgery. Surgical mortality ( < 30 days) was low (1/13) in ascending aortic aneurysm, but higher (3/8) in aneurysm of the descending or thoracoabdominal aorta (including both acute and elective operations). Of the 20 non-surgically managed patients in the latter group, 15 died after a mean of 1.1 year. The only patient operated on for aortic arch aneurysm died of cerebral ischaemia 2 days postoperatively. Most of the 19 non-operated patients with aneurysm of the arch or total aorta (mean age 76 years) were never considered for surgical treatment. The analysis supports aggressive management of patients with aneurysm of the ascending, descending or thoracoabdominal aorta. Many of our patients with aneurysm of the arch or involving most of the aorta were old and had other, concomitant diseases, and in such cases an aggressive treatment strategy does not seem justified.
Scand J Thorac Cardiovasc Surg 1995
PMID:Survival in thoracic or thoracoabdominal aortic aneurysm. Comparison between patients with or without surgical treatment. 861 76

Controversy exists over the value of intraoperative monitoring and shunting in patients undergoing carotid endarterectomy. Although it is widely believed that contralateral carotid occlusion and previous stroke mandate intraoperative shunting, the susceptibility of these two groups of patients to cerebral ischemia during carotid artery endarterectomy is not well defined. Somatosensory evoked potentials (SSEPs) were monitored in 113 carotid artery endarterectomy patients. Of these, 32 (28.3%) had a previous stroke, 24 (21.2%) had a contralateral carotid occlusion and 33 (29.2%) were diabetic. There were no deaths and only one perioperative stroke (0.9%). Cerebral ischemia occurred in 14 patients (12.4%). Six of these patients had a contralateral carotid occlusion. Some 29 patients (25.7%) were shunted, including 10 with contralateral carotid occlusions that did not have major SSEP changes. In the latter half of the study, 14 patients with contralateral carotid occlusions were selectively shunted (six shunted, eight not shunted) with no neurological complications. Thirty-two patients with prior strokes were selectively shunted (nine shunted, 23 not shunted); of these, one shunted patient undergoing combined carotid artery endarterectomy and coronary artery bypass grafting had a perioperative stroke. Intraoperative monitoring with SSEPs accurately identifies cerebral ischemia secondary to carotid clamping as well as patients requiring shunts. With use of intraoperative SSEP monitoring, selective shunting may be safely performed in patients with a contralateral carotid occlusion or a previous stroke.
Cardiovasc Surg 1996 Feb
PMID:Somatosensory evoked potential monitoring during carotid surgery. 863 52

Internal carotid pseudo-occlusion (ICP) is a pathology of difficult diagnostic evaluation and treatment in the group of extracranial carotid diseases. The authors report the results of 24 ICP(S) surgically treated in the last five years. No perioperative death was reported. The neurological morbility rate was as low as 4% (1/24), which is quite a good results for this high-risk pathology. Clinical and instrumental follow-up was performed (at 1-3-6-12-24 months from surgery). Six early asymptomatic thromboses (25%) were observed, and the remaining patients showed patent vessels and no symptoms at all. In conclusion surgical treatment of ICP is often able to prevent cerebral ischaemia, and the high rate of early occlusion should not limit surgical indication.
J Cardiovasc Surg (Torino) 1997 Feb
PMID:Internal carotid pseudo-occlusion: early and late results. 912 16

Ultrasound has provided a highlight of the different types of subclavian steal. The authors report epidemiological and clinical data concerning 40,000 ultrasound examinations performed on epiaortic arteries and particularly the last 12,000 in which Doppler c.w., duplex scanner and transcranial Doppler were used. Various types of steal are described; five types of subclavian steal have been classified and patients stratified as being symptomatic and asymptomatic. The neurological symptoms are divided as follows: generalized cerebral ischemia, vertebro-basilar ischemia and hemispheric ischemia. Based on this clinical and haemodynamic outline, surgical therapy is indicated and type of surgery suggested.
J Cardiovasc Surg (Torino) 1997 Apr
PMID:Classification of the subclavian steal syndrome with transcranial Doppler. 920 Nov 24

Severe cerebrovascular complications following cardiac surgical procedures remain a major concern, particularly in patients with significant carotid atherosclerotic involvement (14% of perioperative stroke). Operative mortality for carotid operations in patients with documented Coronary Artery Disease (CAD) may be as high as 20%. Seventy patients underwent combined operations (unilateral carotid stenosis > 70%, unilateral stenosis > 50% with ulcerated plaque or bilateral stenoses > 50%; and this also included patients with unilateral occlusion). Cardiac procedures were 69 coronary artery bypass grafts, four left ventricular aneurysmectomies, three aortic valve replacements and surgery on two mitral valves. Seven perioperative deaths occurred, which were all caused by cardiac events. There were no perioperative strokes. Carotid endarterectomy immediately before cardiopulmonary bypass is a safe and expeditious approach to coexisting significant cardiac and carotid disease. In our experience, technical details in monitoring and minimizing cerebral ischemia are possibly more crucial in these severe vasculopathic patients. Moreover, it is probably advantageous from an economic standpoint compared with other therapeutic treatments.
Cardiovasc Surg 1998 Oct
PMID:Combined carotid and cardiac procedures: improved results and surgical approach. 979 72

It is believed that moderate hypothermia (25-32 degrees C) during cardiopulmonary bypass provides cerebral protection by reducing the cerebral metabolic rate (CMRO2). Nevertheless episodes of ischaemia do occur and thus it has been suggested that cerebral oxygenation should be monitored by jugular venous oximetry. However, this technique is cumbersome and invasive. Near infrared spectroscopy (NIRS) provides a non-invasive assessment of cerebral oxygenation and this was used together with continuousjugular venous oximetry in 21 patients undergoing hypothermic cardiopulmonary bypass. During the hypothermic period, jugular venous oximetry indicated reduced oxygen extraction consistent with a reduction in CMRO2 (increase from 61 +/- 2.5% to 74 +/- 2.5%). In contrast, near infrared spectroscopy demonstrated increased oxygen extraction (HbO2 - 11.5 +/- 1 microM, HHb + 3.2 +/- 0.3 microM) and a fall in the cerebral concentration of oxidized cytochrome oxidase ( - 1.7 +/- 0.3 microM) indicating ischaemia. These results suggest that cerebral ischaemia occurs during hypothermic cardiopulmonary bypass with a spurious rise in jugular venous oxygen saturation, which represents arterio-venous shunting. Thus if hypothermia does facilitate cerebral protection it does not appear to be a direct result of a reduction in CMRO2 and oxygen requirement.
Cardiovasc Surg 1999 Jun
PMID:Does hypothermia prevent cerebral ischaemia during cardiopulmonary bypass? 1043 May 25

Brain edema is a life-threatening complication of cerebral infarction. The molecular cascade initiated by cerebral ischemia includes the loss of membrane ionic pumps and cell swelling. Secondary formation of free radicals and proteases disrupts brain-cell membranes, causing irreversible damage. New diagnostic methods based on magnetic resonance imaging have markedly improved diagnostic accuracy. Cytotoxic and vasogenic edema is maximal by 24 to 72 hours after the ischemic event. Thrombolytics reperfuse tissue and improve outcome; when treatment is delayed, they can increase edema and blood-brain barrier opening. Although osmotherapy reduces brain water, and is used to treat ischemic edema, its efficacy remains to be proven. As the molecular events become clearer, novel treatments that block different stages of the injury cascade will be available for clinical testing.
Prog Cardiovasc Dis
PMID:Ischemic brain edema. 1059 21

This study investigated the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass in a canine model. The adequacy of cerebral oxygenation was determined from the adenosine concentration, the oxygen saturation of cerebral venous blood and brain oxyhemoglobin level. In experiment 1, nine beagles were cooled on bypass to a nasopharyngeal temperature of 18 degrees C and the perfusion flow rate was reduced in a stepwise fashion every 30 min from 100 to 50, 30, 20 and 10 ml/kg per min. In experiment 2, six beagles were cooled on bypass as in experiment 1, and flow was maintained at 30 ml/kg per min for 120 min. At a perfusion flow rate of 30 ml/kg per min, adequate cerebral oxygenation was maintained for 120 min. In contrast, perfusion flow rates of 20 and 10 ml/kg per min were associated with cerebral ischemia.
Cardiovasc Surg 1999 Dec
PMID:Experimental determination of the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass. 1063 46


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