Influence of poststenotic collateral pressure on blood flow velocities within high-grade carotid artery stenosis: differences between morphologic and functional measurements.

PURPOSE: The driving force for blood flow through a high-grade stenosis in the internal carotid artery can be expressed as the pressure gradient over the stenosis itself, which, however, might be reduced by the back pressure exerted by distal collateral vessels. Theoretically the maximum blood flow velocity as a measure of the functional grade of obstruction may therefore be lower than what is expected from morphologic gradations of the stenosis. This study was designed to test prospectively the influence of intracranial collateral vessels on blood flow velocities within high-grade internal carotid artery stenoses. PATIENTS AND METHODS: Forty-five consecutive patients (age 66 +/- 11) with high-grade internal carotid artery stenoses were investigated before and during carotid endarterectomy. The preoperative investigations included duplex ultrasound scanning of the neck vessels, transcranial Doppler scanning for assessment of collateral flow to the middle cerebral artery and angiography. Carotid endarterectomy was performed with patients under deep general anesthesia without a shunt. Systolic and diastolic internal carotid artery blood pressures were measured before and during intraoperative cross-clamping (ie, stump pressure) of the carotid arteries. RESULTS: Within high-grade internal carotid artery stenoses, maximum systolic and end-diastolic blood flow velocities showed a significant inverse correlation to the corresponding systolic and diastolic stump blood internal carotid artery blood pressures. All patients with spontaneous collateral flow to the ipsilateral anterior part of the circle of Willis were divided into a group with relatively high and another one with low end-diastolic blood flow velocities. The stump pressure was significantly lower in patients with high end-diastolic blood flow velocities in spite of the fact that the mean angiographic grade of stenosis did not differ significantly between the groups. CONCLUSIONS: Flow velocities within a high-grade internal carotid artery stenosis are inversely dependent on the stump pressure, that is the poststenotic collateral perfusion pressure. This should be taken into consideration in case of discrepancies between angiography and ultrasound outcome.

High diastolic flow velocities in severe internal carotid artery stenosis: a sign of increased surgical risk?

PURPOSE: We reviewed the history and preoperative investigations of patients with early postoperative neurologic events after carotid thromboendarterectomy in an attempt to identify risk factors for neurologic complications. METHODS: Patients with neurologic events/complications (S group, n = 14 patients) were compared with an age- and disease-matched control group (C group, n = 42 patients) selected from the whole carotid thromboendarterectomy material between 1987 and 1996. In this retrospective study, we re-evaluated the maximum systolic and end diastolic flow velocities within the internal carotid artery (ICA) using video recordings of preoperative Duplex ultrasound scan investigations. The flow velocity variables were compared with preoperative carotid angiography and intraoperative ICA stump pressure measurement. RESULTS: S-group did not differ from C-group concerning either cardiovascular risk factors or diseases, ipsilateral and contralateral angiographic grade of ICA stenosis, or history of cerebral infarctions. Nevertheless, in contrast to control subjects, patients with early postoperative major stroke had higher end diastolic flow velocities and lower ICA stump pressures. Patients with postoperative minor stroke, transient ischemic attack, or amaurosis fugax did not differ significantly from the control subjects. Among patients with ICA stenosis of 75% or more, end diastolic flow velocities were correlated to the diastolic stump pressures. CONCLUSION: Diastolic flow velocities within severe internal carotid artery stenosis are dependent on the level of the collateral perfusion pressure distally to the stenosis (ie, high values indicate a low internal carotid artery stump pressure), which seems to be a risk factor for early postoperative strokes.

The effect of preoperative needle abrasion of the recipient site on survival of autologous free fat grafts in rats.

Pads of fat ranging from 670-1758 mg in weight were taken from the right groins of 20 rats and implanted subcutaneously over their right pectoral muscles. One week previously the recipient site on the thorax had been abraded with a needle in 10 of the rats. After three months the transplanted fat was taken out, weighed, and examined histologically by light microscopy. Regional tissue blood flow in the transplanted fat and in the fat from the left groin was measured by the microsphere technique. The amount of surviving fat and blood flow in the fat transplanted to an abraded recipient site was significantly higher than in the control group after three months. We conclude that preoperative needle abrasion of the recipient site may increase the chance of revascularisation and survival of the transplanted fat in rats.

Radiation doses to patients and personnel involved in embolization of intracerebral arteriovenous malformations.

Radiation doses to patients and personnel were measured during 5 embolization procedures in 5 different patients. Thermoluminescent dosimeters were used to measure the absorbed doses in different points of the skin of patients as well as personnel. A transmission ionization chamber was used to determine the energy imparted in the patients. The effective dose equivalent HE during the procedures was estimated to be in the range of 6 to 43 mSv to the patients, 10 to 26 microSv to the radiologist in charge of the embolizations, 3 to 24 microSv to the assisting radiographer and 13 to 86 microSv to the nurse anesthetist. Radiation doses to the patients were considerable but the estimated risks from radiation were low compared to the risks of the arteriovenous malformation itself and the hazards of the embolization. The annual radiation doses to the personnel were well below established dose limits.

Laryngeal involvement in rheumatoid arthritis.

Twenty-nine female patients with definite or classical rheumatoid arthritis (RA) and 30 controls were studied in order to assess the prevalence of laryngeal involvement in patients with RA and the occurrence of extrathoracic airway obstruction. Laryngeal involvement was assessed by physical examination including direct fiberoptic laryngoscopy, respiratory function tests and low-voltage radiography. Physical examination revealed laryngeal involvement in 17 RA patients (59%), extrathoracic airway obstruction was indicated by spirometry in 4 (14%) and radiography revealed pathological findings in 3 patients (10%). One or more signs of laryngeal involvement were found in 20 patients (69%). Symptoms of breathing difficulties were common (75%) among patients with laryngeal involvement. The erythrocyte sedimentation rate and class-specific rheumatoid factors were not correlated to laryngeal involvement.

Spinal arteriovenous malformations: neurological aspects and results of embolization.

Twenty consecutive patients with spinal arteriovenous malformations (AVMs) were found to have either a progressive, remitting or remitting-progressive course of disease. A characteristic progressive neurological decline was observed in 11 patients with dural fistulas and a similar decline was seen in 5 of the 9 patients with intradural AVMs. In addition to paraparesis and mixed sensory disorder, which ascended to a level of about T10, areas with spared sensation were occasionally found below this level. All cases with this progressive longitudinal myelopathy showed radiological evidence of a dilated medullary venous plexus. All patients were treated by embolization with only a low frequency of complications. Follow-up data verified a significant improvement of motor and sensory function, mainly during the first year after embolization. Cases with progressive neurological decline (dural and intradural AVMs) stopped deteriorating or improved and cases with a history of acute incidents (intradural AVMs) probably run less risk of acute deterioration.

Embolization of cerebral arteriovenous malformations with bucrylate. Experience in a first series of 29 patients.

The experience with embolization of intracerebral arteriovenous malformations (AVMs) with bucrylate (isobutyl-2-cyanoacrylate) in 29 patients is reported. In 9 cases (31%) less than 1/3 of the AVM nidus was occluded, in 12 (41%) 1/3 to 2/3, in 4 (14%) more than 2/3, and total occlusion was only seen in 3 cases (10%). One patient was never embolized, owing to procedure complications. At follow-up angiography in 20 patients, partial revascularization was found in 11 AVMs and further occlusion in 2. Complications occurred in 11 cases (38%). Five patients (17%) suffered from hemorrhage: 2 died, one deteriorated severely and 2 recovered. Unintentional embolization or edema resulted in neurologic deficits in 6 patients (21%), permanent in 3 and reversible in 3. Symptomatic improvement was initially found in 13 patients (45%) but was stable only in 9. In 9 patients (38%) embolization was followed by elective surgery or irradiation. The best results were obtained in small and medium-sized AVMs (less than 6 cm) while there was a high risk of complications and an uncertain palliative effect in large AVMs.

Laryngeal obstruction assessed by computed tomography.

The aim of this study was to find out if laryngeal obstruction could be assessed by measuring the glottic area using computed tomography (CT). Results from model studies were compared with those from twelve patients with laryngeal diseases. Determination of the orolaryngeal airway resistance (Rol) was used as a reference method. The correlation between airway resistance and area in both the model and among the patients was consistent, with a curvilinear relationship. The results indicate that it is possible to measure the area of a short obstruction by CT and that this area determines the degree of obstruction.

Juvenile nasopharyngeal angiofibroma. A report of eighteen cases.

Juvenile nasopharyngeal angiofibroma is a disease afflicting mainly adolescent males. The lesion is benign but characterized by local aggressive growth. In advanced cases the tumour may extend intracranially. In this study 18 cases of juvenile nasopharyngeal angiofibroma were investigated. Tumour extension was assessed with the use of angiograms and CT and the individual cases staged in four different categories on the basis of tumour extension. Two cases were staged as I (tumour confined to the nasopharynx), 7 cases as II (tumour extending into nasal cavity and/or sphenoid sinus), 8 as III (tumour extending into one or more of the following: antrum, ethmoid sinus, pterygomaxillary and infratemporal fossae, orbit and/or cheek) and one as IV (tumour extending into the cranial cavity). Preoperative arterial embolization was performed in 8 cases. All patients underwent surgery; none received irradiation. The follow-up period was 6 yrs 4 mo (6 months-17 years). In one case of intracranial extension, tumour recurrence occurred. It is concluded that with the aid of CT and arteriograms to evaluate the extension of the tumour and preoperative embolization, this lesion can be cured in the vast majority of cases, with surgery as the method of choice.

Treatment of direct carotid-cavernous fistulas with detachable balloons.

Experience with transarterial treatment of 14 direct carotid-cavernous fistulas using the Debrun technique with detachable balloons manually tied to the catheter is reported. Ten of the fistulas were occluded by balloons with concomitant occlusion of the internal carotid in one case. Another fistula closed spontaneously in connection with the embolization procedure. Three fistulas were treated with surgical trapping after recurrence. The transvenous approach was attempted in three cases but failed. Four complications occurred, two with clinical consequences as the patients developed neurologic deficits. Except in four cases with persistent or slowly regressing orbital palsies all signs and symptoms of the fistula disappeared after successful occlusion. The use of detachable balloons for selective occlusion is in experienced hands a rather safe and simple method with good results. Large fistulas offer most problems, and to avoid progression in fistula size the treatment should be undertaken as soon as possible after diagnosis.

Venous malformations in the face and neck. Radiologic diagnosis and treatment with absolute ethanol.

Venous malformations in the face and neck have a characteristic clinical picture. They consist of a cluster of venous cavities with a very slow blood flow and are normally not demonstrated at conventional external carotid angiography. Previous methods of treatment have been of limited value but recently good results have been reported with instillation of fibrosing agents as Ethibloc and ethanol. Five patients with facial venous malformations were referred for therapy. External carotid angiography was performed and was almost normal in all patients. Superselective catheterization demonstrated the malformation clearly in 2 patients only. Direct puncture phlebography confirmed the diagnosis by demonstrating the venous cavities in all the patients. This procedure was concluded by instillation of absolute ethanol into the cavities. There was a marked reduction in size of the malformation but it was not permanently completely occluded. The treatment was repeated in 4 patients with further reduction of the size, but small remnants are still left. Serious complications with extensive soft tissue necrosis occurred in one patient probably as a result of extravasation of ethanol. The necrosis later healed well after surgical treatment. Instillation of ethanol under radiologic control seems to be a promising way of treatment of venous malformations.

Bone mass of the axial and the appendicular skeleton in women with Colles' fracture: its relation to physical activity.

The aim of this investigation was to elucidate whether Colles' fractures in middle-aged women were indicative of generalized bone loss (osteopenia) and whether bone mass of the axial and the appendicular skeleton was related to the extent of daily physical activity. Thirty-six patients (aged 50-73 years) with previous Colles' fracture were studied. The median time elapse after the injury was 18 months (range 9-20.5 months). Bone mineral content of the 2nd, 3rd, and 4th lumbar vertebrae (lumbar BMC) and both distal forearms (forearm BMC) were determined to dual-photon (153Gd) absorptiometry. The physical activity level was graded according to a standard interview and a bicycle ergometer test. Mean lumbar BMC was reduced by 9% compared to age-matched normal women (p less than 0.05), mean forearm BMC was reduced by 5% (NS). Twenty patients showed spinal osteopenia by either conventional radiography or absorptiometry (95% confidence limits 38-72%). The fracture-related bone loss from the forearms was most prominent when the fracture had occurred in the dominant forearm, suggesting that the loss of 'dominant' forearm activity per se results in bone loss. No relation between working capacity and forearm BMC was found. However, the working capacity was positively related to lumbar BMC (P less than 0.01), even if the common relationship to age was eliminated (P less than 0.05). The data suggest that the bone mass of the axial skeleton reflects the extent of daily physical activity. Patients with Colles' fractures represent an easily definable population which might benefit from prophylactic measures against vertebral bone loss and compression fractures. One of these could be physical exercise.

Assessment of vertebral osteopenia. Comparison of spinal radiography and dual-photon absorptiometry.

A comparison of radiographic morphology and dual-photon (153Gd) absorptiometry was carried out in 132 women. Films of the lumbar spine were graded for osteopenia, spondylosis, and calcification of the abdominal aorta according to definite morphologic criteria. The radiographic grade of osteopenia and the bone mineral content of the 2nd, 3rd, and 4th lumbar vertebrae showed a highly significant inverse correlation. However, the mineral content at each radiographic grade of osteopenia differed considerably. Disproportionately high levels occurred in patients with spondylosis and severe calcification of the abdominal aorta. Spinal radiography and dual-photon absorptiometry must be regarded as complementary rather than alternative diagnostic procedures in clinical practice.