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

In a multicenter study, 120 patients with intracranial aneurysms presenting a high surgical risk were treated using electrolytically detachable coils and electrothrombosis via an endovascular approach. The results of treatment in patients with posterior fossa aneurysms (42 patients with 43 aneurysms) are presented. The most frequent clinical presentation was subarachnoid hemorrhage (24 cases). The clinical follow-up periods ranged from 1 week to 18 months. Complete aneurysm occlusion was obtained in 13 of 16 aneurysms with a small neck and in four of 26 wide-necked aneurysms. A 70% to 98% thrombosis of the aneurysm was achieved in 22 of 26 aneurysms with a wide neck and in three of 16 small-necked aneurysms. One aneurysm could not be treated due to a technical complication. Two cases required postprocedural surgical clipping of a residual aneurysm. One patient (originally in Hunt and Hess Grade V) experienced procedural rupture of the aneurysm requiring an emergency parent artery occlusion. He eventually died 5 days later. Another patient (originally in Grade IV) had coil migration and posterior cerebral artery territory ischemia. A third patient developed a permanent neurological deficit (hemianopsia) after complete occlusion of a wide-necked basilar bifurcation aneurysm. One patient, harboring an inoperable giant basilar bifurcation aneurysm, died from aneurysm bleeding 18 months after partial occlusion. Overall morbidity and mortality rates related to treatment were 4.8% (two cases) and 2.4% (one case), respectively (2.6% and 0% if considering only patients in Hunt and Hess Grades I, II, and III). It is suggested that this technique is a viable alternative in the management of patients with posterior fossa aneurysms associated with high surgical risk. Longer angiographic and clinical follow-up study is necessary to determine the long-term efficacy of this recently developed endovascular occlusion technique. Close postoperative angiographic and clinical monitoring of patients with wide-necked subtotally occluded aneurysms is mandatory to check for potential aneurysmal recanalization, regrowth, and rupture.
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PMID:Endovascular treatment of posterior circulation aneurysms by electrothrombosis using electrically detachable coils. 152 8

The present prospective study, with participation of five of the six neurosurgical centers in Sweden, was conducted to evaluate the overall management results in patients with aneurysmal subarachnoid hemorrhage (SAH). The participating centers covered 6.93 million (81%) of Sweden's 8.59 million inhabitants. All patients with verified aneurysmal SAH admitted between June 1, 1989, and May 31, 1990, were included in this prospective study. A uniform management protocol was adopted involving ultra-early referral, earliest possible surgery, and aggressive anti-ischemic treatment. A total of 325 patients were admitted during the study period, 69% within 24 hours after hemorrhage. On admission, the patients were graded according to the scale of Hunt and Hess: 43 patients (13%) were classified in Grade I, 119 (37%) in Grade II, 53 (16%) in Grade III, 76 (23%) in Grade IV, and 34 (11%) in Grade V. Nimodipine was administered to 269 of the 325 patients: intravenously in 218, orally in 15, and intravenously followed by orally in 36. At follow-up examination 3 to 6 months after SAH, 183 patients (56%) were classified as having made a good neurological recovery, 73 patients (23%) suffered some morbidity, and 69 (21%) were dead. Surgery was performed in 276 (85%) of the patients; emergency surgery with evacuation of an associated intracerebral hematoma was carried out in 30 patients. Early surgery (within 72 hours after SAH) was performed in 170 individuals, intermediate surgery (between Days 4 and 6 post-SAH) in 29 patients, and late surgery (Day 7 or later after SAH) in 47 individuals. Of 145 patients with supratentorial aneurysms who were preoperatively in Hunt and Hess Grades I to III and who were treated within 72 hours, 81% made a good recovery; in 5.5% of patients, the unfavorable outcome was ascribed to delayed ischemia. It is concluded that, among patients with all clinical grades and aneurysmal locations, almost six of 10 SAH victims referred to a neurosurgical unit can be saved and can recover to a normal life.
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PMID:Overall outcome in aneurysmal subarachnoid hemorrhage. A prospective study from neurosurgical units in Sweden during a 1-year period. 156 33

Seven cases of unclippable vertebral artery aneurysms (3 dissecting, 1 fusiform, 2 saccular and 1 giant) are reported. Five of these had subarachnoid hemorrhage, one showed mass effect and the other was found incidentally. Trapping of the involved portion of the vertebral artery was performed in 4 cases, proximal clip occlusion in 2 and proximal balloon occlusion in 1. There were no operative deaths and no rebleeding, but brainstem ischemia developed in 4 cases, two being transient and two permanent. The ischemic complications were possibly due to; (a) hypoperfusion in the transient cases and (b) thromboenbolism, from the partially thrombosed giant aneurysm or thrombosis of the cul-de-sac vertebral artery, in the permanent ones. Preoperative temporary vertebral artery occlusion with an inflatable balloon or postoperative anticoagulant therapy should be considered in the management protocol.
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PMID:[Therapeutic occlusion of unilateral vertebral artery for unclippable aneurysms; special reference to postoperative brainstem ischemia]. 157 52

To delineate the pathophysiology of periventricular hemodynamics in normal pressure hydrocephalus, we performed quantitative and three-dimensional measurements of cerebral blood flow (CBF) by using xenon-enhanced computed tomographic scans. Measurements were made on 7 patients in whom normal pressure hydrocephalus after subarachnoid hemorrhage had been confirmed by clinical improvement after shunting. We compared mean CBF values in the white matter and cortex of the frontal, temporal, parietal, and occipital lobes and in the thalamus before and after shunting, with an evaluation of dementia and the extent of ventricular dilation and periventricular lucency on computed tomographic scans. CBF returned to within normal limits in the white matter of the frontal and temporoparieto-occipital lobes. CBF restoration closely correlated with clinical improvement and reduction in ventricular dilation and periventricular lucency. We speculate that ischemia occurs initially in the periventricular white matter as a result of diffused cerebrospinal fluid and then extends of the cortex and to the thalamus, causing a "misery perfusion" state with neuronal dysfunction. Incomplete improvement of dementia and CBF in the cortex and thalamus may be explained by preexisting arteriosclerosis in aged patients, coexisting brain damage caused by subarachnoid hemorrhage and subsequent surgical insult in aneurysm patients, and delayed recovery of cortical function that has been secondarily impaired by the periventricular lesions.
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PMID:Significance of periventricular hemodynamics in normal pressure hydrocephalus. 158 81

Ischemic brain injury, including infarction, continues to cause major morbidity among operated and non-operated survivors of aneurysmal subarachnoid hemorrhage. Following an introductory description of cerebral vessel pathology, the relationship between angiographic vessel narrowing, or "spasm", and focal clinical deficits attributed to the resulting ischemia is explored. The role of nimodipine is presented with respect to its impact on survival quality. The session concludes with an outline of directions for future research.
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PMID:Vasospasm after aneurysmal subarachnoid hemorrhage: a review of pathophysiology. 159 65

Brain tissue acidosis is considered to play a role in the complex sequence of events following traumatic brain injury. This report reviews the experimental and clinical research conducted at the Medical College of Virginia to help clarify the extent of metabolic derangement that occurs and to evaluate the effect of treatment. Experimental injury models in ventilated animals showed that trauma produces a mild brain tissue acidosis that recovers within hours of injury. Hypoxia combined with trauma produces a relative ischemia and exacerbates the acidosis, which eventually resolves with resuscitation. Other studies revealed that CSF lactate measurements should be interpreted with caution, particularly in patients with subarachnoid hemorrhage. The results of two randomized clinical trials testing therapeutic effects of sustained hyperventilation and treatment with tromethamine (THAM) are discussed.
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PMID:Intracellular acidosis in human and experimental brain injury. 161 13

The objective of this study was to mimic in a simple experiment the two major brain insults sustained by the patient with a subarachnoid hemorrhage, that is, the ictus and the subsequent delayed reduction of focal cerebral blood flow caused by vasospasm without the interference of subarachnoid blood, to test the hypothesis that ictal events not related to the presence of blood in the subarachnoid space per se may be important for the development of ischemic deficits and cerebral infarction when vasospasm develops. Groups of rats were subjected to a sudden transient elevation of the intracranial pressure to a level causing a brief period of complete global ischemia by infusion of mock cerebrospinal fluid into the cisterna magna (this manipulation was designed to allow survival of the animal and recovery of consciousness). Two and one-half hours later, a focal ischemic insult was induced by occlusion of the middle cerebral artery. Rats subjected to middle cerebral artery occlusion alone and sham operation served as controls. The infarct size was used as the end point and was calculated on brain slices stained with 2,3,5-triphenyltetrazolium chloride. The study demonstrates that a brief sudden elevation in intracranial pressure, in itself consistent with survival and recovery, increased the vulnerability of the brain to a subsequent focal ischemic insult. Thus the combination of insults resulted in significantly (P less than 0.05) larger infarcts than did middle cerebral artery occlusion alone. Further, this combination of insults resulted in a disproportionate enlargement of the affected hemisphere, which could not be explained by the increased infarct size alone.
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PMID:Transient elevation of the intracranial pressure increases the infarct size and perifocal edema after subsequent middle cerebral artery occlusion in the rat. 161 92

Most spinal dural arteriovenous malformations are located in the thoracic and lumbar regions. The symptoms include pain, weakness, sensory disturbances, and sphincter dysfunction, which are usually gradual in onset. They are attributed to venous hypertension with a resultant ischemia of the cord, and hemorrhage from them is rare. The authors report an unusual case of a patient with a dural arteriovenous malformation in the cervical spine who was admitted with a sudden onset of severe headache and dysesthesia due to subarachnoid hemorrhage.
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PMID:Dural arteriovenous malformation in the cervical spine presenting with subarachnoid hemorrhage: case report. 164 Oct 89

We evaluated the sensitivity of continuous quantitative EEG in 11 patients with subarachnoid hemorrhage (SAH). We correlated compressed spectral array (CSA) and trend analysis (TA) of total power (1-30 Hz), frequency centroid (1-30 Hz), alpha ratio and percent delta power with clinical and radiological findings. For all ischemic events (n = 11), the most sensitive TA parameter was a change in total power (91%), followed by changes in alpha ratio (64%), frequency centroid (55%), and percent delta (45%). Comparable CSA features were changes in power (44%) and slowing (39%). Total power and frequency varied independently. In 4 cases, EEG findings on TA appeared before clinical changes. Continuous quantitative EEG may be useful for monitoring and predicting ischemia following SAH. TA of individual EEG parameters is more sensitive than CSA, and total power is the most sensitive.
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PMID:Quantitative EEG monitoring for patients with subarachnoid hemorrhage. 171 51

The authors have used intracerebral microdialysis to develop a method for routine monitoring of disturbances in brain energy metabolism in patients in the neurosurgical intensive care unit. Microdialysis was conducted for periods ranging from 2.3 to 8.3 days in four patients (three with severe head injuries and one with severe subarachnoid hemorrhage). Altogether, 4447 chemical analyses from 587 dialysis samples were carried out. Concentrations of the energy-related metabolites lactate, pyruvate, and hypoxanthine were measured, and the lactate:pyruvate ratio was calculated. In addition, the acids glutamate, aspartate, taurine, glutamine, asparagine, and glycine were measured in one patient. The microdialysis data were matched with various clinical events, including intracranial hypertension and therapeutic interventions such as initiation or withdrawal of barbiturates and cerebrospinal fluid drainage. The present study shows that microdialysis can be used for long-term measurement of extracellular fluid (ECF) energy-related metabolites and amino acids in the frontal cortex of neurosurgical patients in a clinical setting. Fluctuations of the measured ECF energy-related substances corresponded to various clinical events presumably involving hypoxia/ischemia. The authors found a 25-fold increase in ECF glutamate, aspartate, and taurine under conditions of energy perturbation, as indicated by high levels of the lactate:pyruvate ratio, lactate, and hypoxanthine. The use of long-term intracerebral microdialysis in patients opens a new field of clinical research, with many possibilities for improving insight into intracranial dynamics in acute cerebral conditions.
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PMID:Chemical monitoring of neurosurgical intensive care patients using intracerebral microdialysis. 172 72


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