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ABSTRACT: The purpose of this study was to disclose the frequency of new infarcts after Carotid Endarterectomy (CEA) by MRI and Transcranial Doppler examinations (TCD), and to evaluate the clinical and pathological significance. Of a consecutive series of 41 patients with a symptomatic carotid stenosis exceeding 69%, 33 had MRI and TCD examinations performed before and after the CEA. Pre-operative MRIs revealed Focal High Signal Intensity (FHSI) in 21 patients (64%) on the side of the stenosis, ranging in number from 2 to more than 20 and in size from 0.5 cm to more than 3 cm. After the operation 8 patients (24%) each had acquired from 1-4 new FHSIs, but only 3 patients (9%) suffered from clinical symptoms. In 2 patients, who had had a stroke, the FHSIs were more than 3 cm. In 1 patient, who experienced a Transient Ischemic Attack (TIA), the FHSI was 1-2 cm. The TCD disclosed low Pulsatility Index (PI) values in 2 of the 3 patients who had new FHSIs and clinical symptoms. In all the patients who did not show new FHSIs after the operation, the PI was normal in the MCA of the symptomatic hemisphere after CEA. So new cerebral FHSIs were rather frequent after a CEA, but only FHSIs >1 cm were accompanied by a TIA or stroke, and a low PI in the MCA of the relevant hemisphere was found before or in connection with the operation in 2 of the 3 patients who developed clinical symptoms.
Acta Neurologica Scandinavica 09/1999; 100(2):106-10. · 2.47 Impact Factor
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ABSTRACT: Seventy-six patients undergoing carotid endarterectomy were studied to estimate the effect of operation, evaluate the accessible methods of examination and disclose the complications owing to the operation. In addition, the hypothesis that the pulsatility index in MCA measured by the Doppler method could disclose severe ischemia and risk of complications during endarterectomy was tested. The study was a prospective study of patients operated at the University Hospital in Odense in the years 1991-1996. Data collected included demographics, operative indications, complications, follow-up extra/transcranial Doppler examinations, cerebrovascular reactivity investigations, recurrent symptoms and deaths. Concerning the carotid stenosis, a fairly good correlation was found between the results of extracranial Doppler examinations, Duplex and carotid angiography. Serious complications after surgery were few. One patient, who had a coronary by-pass operation consecutive to the endarterectomy, died 3 weeks after the operation, owing to a hematothorax. Five patients (7%) suffered a stroke. Only 2 patients needed rehabilitation, and they came out with minor disturbances in the use of a hand. Recurrent stenosis in excess of 69% emerged in 3% of the patients. All were hemodynamically insignificant. One patient had a new TIA during the observation time of 3-60 months. After the operation she had a thrombosis in the operated carotid artery. Thus our results, a perioperative stroke rate of 7% and a mortality rate of 1%, are in line with the average results in multicenter trials. In addition a PI below 0.60 in the MCA seemed to be a warning of the risk of postoperative cerebral hyperemia.
Acta Neurologica Scandinavica 07/1999; 99(6):340-8. · 2.47 Impact Factor
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ABSTRACT: The relation between angiographically determined cerebral vasospasm following a subarachnoid hemorrhage and regional cerebral blood flow (CBF) was studied in 63 investigations of 45 patients. The CBF was measured using the intra-arterial 133-Xe clearance technique within one hour of angiography. A positive correlation between regional CBF and diameter of major supplying vessel was observed. However, in the 13 cases with focal vasospasm the reduction in CBF was global and not restricted to the area of the spastic vessel. The cerebral oxygen extraction was reduced but independent of the degree of vasospasm, speaking against vasospasm as the cause for the reduction in CBF. The observed association between reduction in CBF and vasospasms could be caused by a common factor responsible for development of both. Thus, it is proposed that the amount of blood escaping at time of aneurysm rupture determines 1) the amount of reduction in cerebral oxygen uptake and thereby the reduction in CBF and 2) the degree of vasospasm. If so a correlation, yet not causal, between reduction in CBF and degree of vasospasm, will be observed.
Acta Neurologica Scandinavica 09/1990; 82(2):109-15. · 2.47 Impact Factor
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ABSTRACT: The cerebral vasomotor reactivity to arterial hypotension and hypocapnia was studied in 34 patients between the 3rd and 13th day after rupture of an intracranial saccular aneurysm. Using the intra-arterial xenon-133 injection method, regional cerebral blood flow (rCBF) and cerebral metabolic rate of oxygen (CMRO2) were measured. The intraventricular pressure and cerebrospinal fluid (CSF) lactate and pH levels were determined. The degree of vasospasm was measured on angiograms taken immediately following the rCBF study. The patients were graded clinically according to the system of Hunt and Hess. Cerebral autoregulation was intact in patients in good clinical condition, but was impaired in patients in poor clinical condition. There was a close correlation between the degree of vasospasm and the degree of autoregulatory impairment, which varied from focal disturbances to global impairment. Intracranial hypertension and CSF lactic acidosis were commonly found in association with vasoparalysis. Cerebrovascular response to hyperventilation was generally preserved, although often reduced. During hyperventilation, the cerebral perfusion pressure became elevated, and increases in CMRO2 were often found, even in patients with severe diffuse spasm and cerebral ischemia. The clinical significance of the results in relation to the treatment of delayed cerebral ischemia and to the use of intraoperative induced hypotension is discussed.
Journal of Neurosurgery 02/1985; 62(1):59-67. · 2.96 Impact Factor
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ABSTRACT: Regional cerebral blood flow (rCBF), cerebral metabolic rate of oxygen (CMRO2), intraventricular pressure, and lactate/pH levels in the cerebrospinal fluid (CSF) were measured in 38 patients with ruptured intracranial aneurysms between the 3rd and 13th day after subarachnoid hemorrhage (SAH). Angiography was performed following the rCBF study and the degree of vasospasm was measured on the angiograms. The patients were graded clinically according to the system of Hunt and Hess. Cerebral vasospasm significantly influenced rCBF: global reductions and focal changes (ischemia, hyperemia, and tissue peaks) were commonly associated with vasospasm. Patients with severe diffuse spasm always had global ischemia (21 +/- 5 ml/100 gm/min), and cerebral infarctions were demonstrated subsequently, The CMRO2 was more reduced than rCBF, indicating an uncoupling between flow and metabolism. This relative luxury perfusion was associated with CSF lactic acidosis and intracranial hypertension. The arteriovenous difference of oxygen was equally reduced in all categories of patients, probably due to the primary insult of SAH. The CMRO2 decreased concomitantly with arterial caliber, indicating a secondary impairment of cerebral metabolism due to vasospasm.
Journal of Neurosurgery 02/1985; 62(1):48-58. · 2.96 Impact Factor
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ABSTRACT: Continuous monitoring of intraventricular pressure (IVP) was performed before and during 13 recurrent hemorrhages occurring in 10 patients between the 3rd and 14th day after the initial rupture of an intracranial saccular aneurysm. Before re-rupture, nine patients were of Hunt and Hess' clinical Grade III of IV. Severe angiographic vasospasm was demonstrated in six patients. In the period between ruptures, IVP and mean arterial blood pressure were significantly increased compared to pressures in patients who did not rebleed. Ventricular drainage of cerebrospinal fluid (CSF) to a level of 25 mm Hg did not increase the rate of rebleeding (17% of patients). On the other hand, the use of drainage while the repeat rupture was taking place seemed to exert a deleterious effect on the natural mechanisms that lead to arrest of hemorrhage. In five patients with CSF drainage during their rebleed, the steady-state IVP level after the repeat rupture was significantly increased, and four patients died from large intracerebral hemorrhages. These results suggest that drainage of CSF should be avoided during recurrent hemorrhage, and should not be resumed until a steady-state IVP level has been reached.
Journal of Neurosurgery 07/1982; 56(6):784-9. · 2.96 Impact Factor
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ABSTRACT: Intraventricular pressure (IVP) was measured continuously by the method of Lundberg for an average period of 8 days in 52 patients with recent rupture of an intracranial saccular aneurysm. The patients were graded as follows according to the system of Hunt and Hess: 13 patients were Grades I-II, 19 patients Grades II-III, and 20 patients Grades III-V. The degree of cerebral arterial spasm was measured on angiograms taken on admission and approximately 7 days later. Drainage of ventricular cerebrospinal fluid was performed intermittently when IVP exceeded 25 mm Hg. The results showed a close correlation between changes in clinical grade and in mean IVP. Drainage improved the condition in uncomplicated cases, but was less effective or ineffective when severe vasospasm or rebleeding occurred. Lowering the IVP by drainage did not appear to increase the risk of rebleeding. In contrast to patients with no or slight spasm, patients with severe spasm had a permanently elevated IVP, even before spasm was demonstrable angiographically. A mean IVP exceeding 25 mm Hg for the whole period of monitoring was associated with a poor prognosis. Finally, indications for continuous monitoring of IVP and ventricular drainage in aneurysm patients are suggested.
Journal of Neurosurgery 03/1982; 56(2):186-96. · 2.96 Impact Factor
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ABSTRACT: Lactate concentrations and pH were measured serially in the cerebrospinal fluid (CSF) of 52 patients with ruptured intracranial aneurysms. Measurements were made during continuous monitoring of the intraventricular pressure (IVP) in the first 12 days after the initial subarachnoid hemorrhage. A total of 226 samples of CSF were analyzed. The clinical condition of the patients was graded according to the Hunt and Hess system. The degree of cerebral arterial spasm was measured on angiograms taken on admission and again approximately 7 days later. Results showed that the lactate concentrations in hemorrhagic and xanthochromic CSF were significantly higher than in clear CSF, indicating lactate production from shed blood cells. However, regardless of the degree of blood admixture to CSF, lactate increased with deteriorating clinical condition. Patients with a moderately increased IVP (20 to 40 mm Hg) had lactate levels of about 3 mmol/liter. A rising IVP or the development of severe spasm was accompanied by a persistent elevation or an increase in lactate. These results suggest that increased CSF concentrations of lactate reflected an increased production of lactate by partially ischemic cerebral tissue. A CSF lactate value above 3.5 mmol/liter was associated with a poor prognosis.
Journal of Neurosurgery 03/1982; 56(2):197-204. · 2.96 Impact Factor
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ABSTRACT: In order to evaluate the reproducibility of regional cerebral blood flow (rCBF) measurements in pathological brain tissue, serial measurements were carried out in 13 determinations performed in patients who were comatose after severe head injuries within the first 2 weeks after the head trauma. The xenon-133 intra-arterial method was used for the flow measurements, and the flow was studied separately in 16 areas of the brain, producing 197 regional double determinations. The patients were maintained in a steady state during and between the measurements, and only differences of less than 2 mm Hg in the arterial CO2 pressure and less than 5 mm Hg in the perfusion pressure were tolerated. The reproducibility was found to be reasonably good as regards initial slope-flow indices and height/area flow indices and height/area flow values, whereas that of the compartmentally calculated flow parameters was poorer. On dividing the series into severely and moderately pathological areas, it could be shown that the reproducibility of the flor values in the moderately pathological brain areas was acceptable and similar to the results reported by others, whereas the reproducibility in the most severely pathological areas of the brain was rather poor, as regards the flow in the fast compartments. The correlation between the various flow parameters was found to be fairly good.
Journal of Neurosurgery 10/1978; 49(3):366-77. · 2.96 Impact Factor
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ABSTRACT: Regional cerebral blood flow (rCBF), cerebral intraventricular pressure (IVP), systemic arterial blood pressure, and cerebral ventricular fluid (CSF) lactate and pH were studied repeatedly in 23 patients during the acute phase of severe brain injury lasting from 3 to 21 days after the trauma. Cerebrovascular autoregulation was tested repeatedly by means of angiotensin infusion in 21 of the patients, and CO2 response in 14 by means of passive hyperventilation. The pressure in the brain ventricles was measured continuously in all patients and kept below 45 mm Hg during the study. If the IVP increased more than 10 mm Hg during the angiotensin infusion (as in one case), the autoregulation test was considered contraindicated and the angiotensin infusion was discontinued. Dissociation between cerebrovascular autoregulation and CO2 response was a common phenomenon. Typically, autoregulation appeared preserved in the most severely injured areas of the cerebral cortex when the patient was deeply comatose, but deteriorated concomitantly with recovery; by the time the patient became alert, the autoregulation was always impaired. The CO2 response was impaired only in patients who were deeply comatose and had attacks of decerebrate rigidity; during recovery the CO2 response became normal. Thus, preserved autoregulation associated with imparied CO2 response indicated very severe brain damage, whereas impaired autoregulation associated with preserved CO2 response suggested moderate or severe brain damage in recovery. These paradoxical observations raise the question whether the preserved autoregulation seen in severely injured brain tissue is a true autoregulation caused by an active vasoconstrictor response to an increase in blood pressure.
Journal of Neurosurgery 06/1978; 48(5):689-703. · 2.96 Impact Factor
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Advances in neurology 02/1978; 20:511-6.
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ABSTRACT: Bicompartmental analysis for the calculation of regional cerebral blood flow (rCBF) from 133Xe clearance in brain tissue has not been thoroughly explored in clinical studies. Most authors rely either on the average rCBF obtained by height/area analysis of the clearance curves or on the initial-slope flow index. Possibly the reason is that the validity of the bimodal flow distribution in abnormal brain tissue is considered questionable. In the present study, bicompartmental analysis, performed by a least-square computerized iterative approach, was used in the calculation of the flow and weight of the tissue of the brain of patients with severe head injuries. The analysis was found to give important information of the nature and course of the brain lesions even if the clearance curves did not have the normal bi-exponential shape, provided the results obtained were properly interpreted. In such cases, the values of the flow and relative weight could not be taken as flow and weight values of gray and white matter, but rather as indices of fast and slower flow components. The interpretation of the results was based on the identification of three types of 13-minute clearance curves, each being characteristic of a type of brain lesion. The clearance curves from fairly normal brain tissue appeared to be bi-exponential; curves from areas of severe cortical contusion had, in addition, an initial and rapid "third" component, a tissue peak, whereas curves from severely edematous brain tissue approached the monoexponential shape.
Journal of Neurosurgery 12/1977; 47(5):699-712. · 2.96 Impact Factor
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Acta neurologica Scandinavica. Supplementum 02/1977; 64:514-5.
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ABSTRACT: Cerebral ventricular fluid (CSF) lactate and pH were measured repeatedly in 21 comatose patients with severe head injury during the first three weeks after trauma. In addition, regional cerebral 133Xe blood flow (rCBF) was measured two to four times in each patient at various time intervals, depending on the indications for carotid angiography, and the pressure in the cerebral ventricular system (IVP) was measured continuously. The series was divided into three groups: (1) patients with local cortical cerebral lesions, (2) patients with brain-stem symptoms, and (3) patients with both local cortical lesions and brain-stem symptoms. The results showed that a high CSF lactate level in patients with severe acute brain injury suggested severe and extensive brain lesions and predicted a poor outcome of the injury. In the individual patients, increasing CSF lactate foreboded clinical deterioration, whereas decreasing CSF lactate indicated recovery. The CSF pH was decreased in most patients, but very low pH levels (below 7.20) were seen only in three patients who all had a poor outcome. Correlation was not observed between CSF lactate and rCBF or between CSF pH and rCBF. It is concluded that repeated determination of CSF lactate and pH during the post-traumatic period may be a valuable tool in the assessment of the course and outcome of the brain injury.
Clinical Neurology and Neurosurgery 02/1977; 80(4):213-25. · 1.58 Impact Factor
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ABSTRACT: The authors measured regional cerebral 133xenon (133Xe) blood flow (rCBF), intraventricular pressure (IVP), cerebrospinal fluid (CSF) pH and lactate, systemic arterial blood pressure (SAP), and arterial blood gases during the acute phase in 23 comatose patients with severe head injuries. The IVP was kept below 45 mm Hg. The rCBF was measured repeatedly, and the response to induced hypertension and hyperventilation was tested. Most patients had reduced rCBF. No correlation was found between average CBF and clinical condition, and neither global nor regional ischemia contributed significantly to the reduced brain function. No correlation was found between CBF and IVP or CBF and cerebral perfusion pressure (CPP). The CSF lactate was elevated significantly in patients with brain-stem lesions, but not in patients with "pure" cortical lesiosn. The 133Xe clearance curves from areas of severe cortical lesions had very fast initial components called tissue peaks. The tissue peak areas correlated with areas of early veins in the angiograms, indicating a state of relative hyperemia, referred to as tissue-peak hyperemia. Tissue-peak hyperemia was found in all patients with cortical laceration or severe contusion but not in patients with brain-stem lesions without such cortical lesions. The peaks increased in number during clinical deterioration and disappeared during improvement. They could be provoked by induced hypertension and disappeared during hyperventilation. The changes in the tissue-peak areas appeared to be related to the clinical course of the cortical lesion.
Journal of Neurosurgery 03/1976; 44(2):191-214. · 2.96 Impact Factor
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ABSTRACT: In 26 patients with recent rupture of an intracranial saccular aneurysm the CSF concentrations of serotonin (5-HT) were measured repeatedly by a radioimmunoassay. The 5-HT level in ventricular CSF collected between the 2nd and 15th day after SAH ranged between less than 2 and 5 nmol/l. These did not differ from the levels found in the ventricular CSF (less than 2-3 nmol/l) and lumbar CSF (less than 2-3 nmol/l) of control patients. 5-HT concentrations did not correlate with the severity of angiographical vasospasm, nor with CSF pressure or clinical grade. In two patients with severe postoperative vasospasm, however, cisternal CSF collected during operation and contaminated by fresh blood showed 5-HT concentrations exceeding 25 nmol/l. Thus, although these results do not support the conception that 5-HT plays a major role in sustaining delayed vasospasm, they suggest that 5-HT liberated from platelets may be operative in the initiation of cerebral arterial spasm.
Stroke 13(2):184-9. · 5.73 Impact Factor
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ABSTRACT: Cerebral ventricular fluid (CSF) lactate and pH were measured repeatedly in 21 comatose patients with severe head injury during the first three weeks after trauma. In addition, regional cerebral 133Xe blood flow (rCBF) was measured two to four times in each patient at various time intervals, depending on the indications for carotid angiography, and the pressure in the cerebral ventricular system (IVP) was measured continuously. The series was divided into three groups:(1)patients with local cortical cerebral lesions,(2)patients with brain-stem symptoms, and(3)patients with both local cortical lesions and brain-stem symptoms. The results showed that a high CSF lactate level in patients with severe acute brain injury suggested severe and extensive brain lesions and predicted a poor outcome of the injury. In the individual patients, increasing CSF lactate foreboded clinical deterioration, whereas decreasing CSF lactate indicated recovery. The CSF pH was decreased in most patients, but very low pH levels (below 7.20) were seen only in three patients who all had a poor outcome. Correlation was not observed between CSF lactate and rCBF or between CSF pH and rCBF. It is concluded that repeated determination of CSF lactate and pH during the post-traumatic period may be a valuable tool in the assessment of the course and outcome of the brain injury.
Clinical Neurology and Neurosurgery.
