Outcome for patients with carotid stenosis undergoing carotid endarterectomy, the cerebral condition followed by extra/intracranial ultrasound examinations.

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.

Cerebral infarct following carotid endarterectomy. Frequency, clinical and hemodynamic significance evaluated by MRI and TCD.

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.

Percutaneous transluminal angioplasty in selected patients with severe carotid artery stenoses: the results of a consecutive series of 24 patients.

OBJECTIVES: To assess clinically and with duplex scanning the results of percutaneous transluminal angioplasty in a subgroup of patients with carotid artery stenosis. DESIGN: A retrospective study. MATERIALS: Twenty-four patients with focal hemispheric neurological symptoms from a concentric, smooth carotid stenosis more than 70% treated with balloon dilatation. Control investigations were performed with duplex scanning. RESULTS: Angiography after PTA revealed no residual stenosis in 15 patients (62%), a stenosis of less than 50 was seen in seven patients (30%) and PTA was ineffective in two patients (8%). Three patients (13%) had transient ischaemic attacks during the procedure but none had strokes. One patient experienced short lasting paraesthesia of the arm a few hours after the PTA procedure. After a follow-up of a mean of 11 months (1-38) no recurrent symptoms had occurred. Clinical success was thus achieved in 22 of 24 patients (92%). At duplex scanning, 16 (66%) patients had no stenosis, six patients (30%) had a stenosis of 70%, one patient (4%) a stenosis of 80%, and one patient had an occluded carotid artery. CONCLUSION: Our results indicate that PTA in a selected group of patients with carotid artery stenosis is safe and the interim, long-term results are promising. The procedure must be evaluated in a randomised prospective study against surgical treatment.

Transcranial Doppler recordings in raised intracranial pressure.

The pulsatility index (PI) registered by the transcranial doppler (TCD) was examined in relation to arterial pCO2 (paCO2) and epidural pressure (ICP). In 10 normal subjects PI was studied during variations in paCO2. In 10 neurosurgical patients with head injuries concomitant measurements of PI and ICP were obtained. The results showed a negative exponential correlation between PI and paCO2. PI changes with 3.2% pr mmHg paCO2. A positive exponential correlation between PI and ICP was observed. PI changed with 2.4% pr mmHg ICP. In the subgroup of patients with raised ICP (15 mmHg <) paCO2 was found not to influence the PI-reflection of the ICP, probably because paCO2-changes affected PI as well as ICP. The results suggest that the noninvasive bedside TCD-registration may be a useful marker of the ICP and probably replace the former invasive methods of measuring ICP.

[Apoplexy--the acute phase]. / Apopleksi--den akutte fase.

This review concerns the acute phase of stroke. It describes incidence, prevalence, etiology, diagnosis and treatment together with the possibilities for prevention. The incidence of stroke in the Danish population is about 2/1000 person years and has been largely unchanged during the last 20 years. About 85% of strokes are caused by cerebral infarcts, ten percent by intracerebral haemorrhages and about five percent by subarachnoid bleeding. The incidence increases with age. Up till age 65 years the ratio between men and women is two to one, while the ratio in the oldest age group approaches one to one. The most important risk factors for stroke are smoking, arterial hypertension, previous cerebrovascular disease, heart disease and diabetes mellitus. Till now, no treatment has been documented as effective in reducing the cerebral damage caused by acute stroke. Ongoing controlled clinical trials in the acute state of ischaemic stroke are testing the effect of thrombolytic therapy, treatment with calciumantagonists, aspirin and heparin. The general medical treatment including nursing and physiotherapy in the acute phase is described. Within recent years benefit of various strategies of stroke prevention has been documented.

[Apoplexy--the acute stage]. / Apopleksi--den akutte fase.

This review concerns the acute phase of stroke. It describes incidence, prevalence, etiology, diagnosis and treatment together with the possibilities for prevention. The incidence of stroke in the Danish population is about 2/1000 person years and has been largely unchanged during the last 20 years. About 85 per cent of strokes are caused by cerebral infarcts, ten percent by intracerebral haemorrhages and about five per cent by subarachnoid bleeding. The incidence increases with age. Up till age 65 years the ratio between men and women is two to one, while the ratio in the oldest age group approaches one to one. The most important risk factors for stroke are smoking, arterial hypertension, previous cerebrovascular disease, heart disease and diabetes mellitus. Till now, no treatment has been documented as effective in reducing the cerebral damage caused by acute stroke. Ongoing controlled clinical trials in the acute state of ischaemic stroke are testing the effect of thrombolytic therapy, treatment with calcium antagonists, glutamate receptor antagonists, aspirin and heparin. The general medical treatment including nursing and physiotherapy in the acute phase is described. Within recent years benefit of various strategies of stroke prevention has been documented.

Cerebral blood flow and metabolism following subarachnoid haemorrhage: effect of subarachnoid blood.

The amount of effused blood following a subarachnoid haemorrhage (SAH) was estimated in 48 patients by cerebral computerized tomographic scanning. The cerebral oxygen consumption (CMRO2) was calculated as arteriovenous difference for oxygen multiplied by mean cerebral blood flow measured by the 133-Xe inhalation technique. A significant negative correlation was observed between CMRO2 and amount of subarachnoid blood, with additional reduction in CMRO2 in case of ventricular bleeding. Cerebral blood flow on admission, opposed to CMRO2, showed no correlation to amount of blood on CT scan. A correlation was observed for blood flow measured at day 5 and further on, indicating a restored coupling between flow and metabolism. The clinical (Hunt) grade on admission and the outcome correlated to the amount of blood. These observations suggest that the acute reduction in CMRO2 following a SAH is mainly determined by the amount of blood escaping during the aneurysm rupture, and that the cerebral blood flow level a few days after SAH mainly is determined by the initial reduction in oxygen uptake.

Spasm index in subarachnoid haemorrhage: consequences of vasospasm upon cerebral blood flow and oxygen extraction.

A spasm index, defined as transcranial Doppler detected flow velocity in the middle cerebral artery divided by regional cortical cerebral blood flow (CBF), was used on 24 patients with subarachnoid haemorrhage (SAH). The aim was to estimate degree and time course of vasospasm, even in cases with great day-to-day variation in CBF, and correlate to CBF and oxygen extraction. All patients showed increase in spasm indices with peak index in the second or third week. The index seemed stable in spite of day-to-day fluctuations in CBF. Severe vasospasm were associated with poor clinical condition, reduced CBF (less than 30) and high AVDO2. The same picture could be seen with minor degree of vasospasm, probably, in some cases, due to high intracranial pressure. The results suggest that the spasm index is useful in monitoring patients with subarachnoid haemorrhage, and that severe vasospasm has a negative influence on clinical condition, CBF and oxygen extraction.

Cerebral blood flow and metabolism following subarachnoid haemorrhage: cerebral oxygen uptake and global blood flow during the acute period in patients with SAH.

Forty-eight patients with subarachnoid haemorrhage were studied with repeated rCBF and CMRO2 measurements. Cortical rCBF was measured using xenon-inhalation technique. CMRO2 was calculated as AVDO2 x CBF. When first studied the 29 conscious patients showed relative hyperaemia with CBF at 50 ml and reduced CMRO2 at 2.17 ml. In the following week CBF decreased to 41. CMRO2 remained reduced and constant. The 19 unconscious patients showed initially pronounced reduction in CMRO2 to 1.26, followed by gradual increase to 1.73 in 4-5 days. Simultaneously CBF increased from 18 ml to slightly above 30 ml. In the conscious patients the early reduction in CMRO2 and the concomitant luxury perfusion may be explained by global ischaemia because of very high ICP at the time of the haemorrhage. The reduced CBF in the unconscious group could be due to increased ICP, as ventricular drainage increased CBF to levels of relative hyperaemia as demonstrated in one case. As no decrease in CMRO2 was seen during the first 2 weeks, it is suggested that ischaemia at the time of aneurysm rupture is the most important single factor in reduction of global CMRO2.

Relation between angiographic cerebral vasospasm and regional CBF in patients with SAH.

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.

Problems in cerebral blood flow calculation using xenon-133 in patients with pulmonary diseases.

We used the end-tidal concentration of xenon-133 (air curve) to estimate the profile of its arterial concentration in calculating cerebral blood flow. We examined the effects of pulmonary disease and artificial ventilation on the air curve and the calculated cerebral blood flow. We studied the relation between arterial and end-tidal xenon activities in 19 subjects, of whom 15 had pulmonary dysfunction. The t 1/2 of the declining phases of the arterial and air curves were used to express their shapes. The mean +/- SD reference t 1/2 from 15 normal volunteers was 26.8 +/- 8.4 seconds. The mean +/- SD t 1/2 s of the air and arterial curves from the 15 patients with pulmonary dysfunction were 10.4 +/- 2.9 and 33.8 +/- 10.9 seconds. The degree of pulmonary dysfunction (expressed as the pulmonary shunt percentage) correlated with distortion of the air curve. Substituting the arterial for the air curve, mean calculated cerebral blood flow (as the initial slope index) increased from 40 to 61 for the 12 patients with chronic obstructive pulmonary disease. The degree of underestimation of cerebral blood flow using the air curve correlated with the pulmonary shunt percentage. Our work confirms the problems of estimating cerebral blood flow in subjects with pulmonary dysfunction.

Retrograde catheterization of the right internal jugular vein for serial measurements of cerebral venous oxygen content.

Serial measurements of CBF and metabolism require multiple cerebral venous blood samples. Retrograde catheterization of the right internal jugular vein is easily performed at a point 2.5-3 cm lateral to, and 2 cm above, the medial end of the right clavicula. Complications are few and minor. In 1/80 (1.25%) cases the carotid artery was punctured during cannulation. Insertion of the catheter for 16-18 cm reduces contamination with extra-cerebral blood to a minimum.

Reversible ischemic neurological deficit and minor strokes before and after EC/IC bypass surgery. A neuropsychological study.

Thirty-three patients with reversible ischemic deficits or completed minor strokes had their cerebral function measured neuropsychologically a few days before and 3 months after extra-intra cranial bypass surgery. Three months post-operatively bypass patency was demonstrated by angiography. Ten patients were operated on the right side and 23 on the left side. The right hemisphere patients were found to be neuropsychologically intact or only slightly impaired before, as well as after, the operation whereas the left hemisphere patients pre-operatively had impaired verbal sequential thinking, reduced capacity for repetition, verbal learning, and mental arithmetic. Post-operatively they improved significantly on 5 of 15 tests and performed no worse on any test than the control group. Consequently, they, too, had post operatively no or only slight neuropsychological impairment.

CBF in head injury.

In the last few years the possibility of measuring CBF by means of intravenous isotop injection technique and portable monitor has made the use of measuring CBF in the clinical setting of the brain injured patient of current interest. However, knowledge about the hemodynamics of the head trauma is inevitable for the interpretation of the CBF results. In this communication a short outline of the results obtained during the last decades studies about the hemodynamic of the damaged brain is given. The essence of these studies seems to be: The local level of CBF do not indicate the severity of the brain injury, as low as well as high flow may be seen initially in severely injured brain tissue. The oxygen uptake (CMRO2) is related to the severity of the brain trauma, as low CMRO2 correlate to poor clinical condition. In severely damaged brain tissue the autoregulation may appear normal (false autoregulation) whereas the autoregulation in moderately damaged tissue may appear impaired for weeks. The carbon dioxide response (CO2) is only impaired if the brain tissue is severely damaged. Thus, low CMRO2 and dissociation between apparently normal autoregulation and impaired CO2 response seem to predict poor outcome.

A neuropsychological study of 12 patients with transient ischemic attacks before and after EC/IC bypass surgery.

A neuropsychological study of 12 patients with transient ischemic attacks from the carotid artery territory was carried out about 2 months following their latest attack, about a week before STA/MCA bypass operation, and again 3 months postoperatively. The results suggest that the TIA patients as a group were slightly intellectually impaired preoperatively. After the operation, a minor neuropsychological improvement had taken place although they still were not fully intellectually rehabilitated.

Regional CBF, intraventricular pressure, and cerebral metabolism in patients with ruptured intracranial aneurysms.

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.

Cerebrovascular reactivity in patients with ruptured intracranial aneurysms.

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.

Intracranial pressure changes following aneurysm rupture. Part 3: Recurrent hemorrhage.

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.

CSF serotonin concentrations and cerebral arterial spasm in patients with ruptured intracranial aneurysm.

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.