Fibromuscular Dysplasia May Herald Symptomatic Recurrence of Cervical Artery Dissection

BACKGROUND

The prevalence of fibromuscular dysplasia (FMD) in patients with cervical artery dissection (CAD) is unknown. Our objectives were to assess the risk of CAD recurring as a stroke or a transient ischemic attack and the association of these events with FMD.

METHODS

We prospectively included and followed 103 consecutive patients who had been admitted for a CAD. The median follow-up was 4 years (range 4 months to 10 years). The main criteria for inclusion were a mural hematoma demonstrated by cervical magnetic resonance imaging and/or signs suggesting CAD on 2 other investigations. FMD was diagnosed on the so-called string of beads pattern by digital subtraction angiography.

RESULTS

Five patients had CAD recurrence (60% occurred late). Four of these 5 patients had FMD. In 4 patients, CAD recurrence involved another cervical artery.

CONCLUSION

The rate of symptomatic CAD recurrence was 1% per year and was often related to FMD.

Duplex Scanning Diagnosis of Internal Carotid Artery Dissections

BACKGROUND

The reliability of duplex scanning (DS) for the diagnosis of internal carotid artery dissections (ICAD) is not clear.

METHODS

Nine DS signs known to be suggestive for the diagnosis of ICAD were compared between 70 patients with ICAD and 70 matched patients without dissection.

RESULTS

Visible internal tapering occlusion, regular eccentric narrowing channel, ectasia beyond the carotid bulb, resistive index asymmetry, blood flow slowdown, ophthalmic artery blood flow inversion, and biphasic flow are more frequent in cases than in controls (p < 0.001). Atheroma plaques were absent in 80% of ICAD. When DS direct signs and hemodynamic signs were studied, sensitivity was 90% and specificity 60%.

CONCLUSION

Diagnosis of ICAD by DS could be improved if direct signs were combined with hemodynamic signs, giving a high sensitivity and a rather good specificity.

Accuracy of color-Doppler in the quantification of proximal vertebral artery stenoses

BACKGROUND

Vertebrobasilar (VB) strokes appear to have the same causes as carotid strokes. Obstructive lesions of proximal vertebral arteries probably occur in about 30% of stroke patients.

PURPOSE

Our aim was to assess the validity of color Doppler sonography compared to selective intra-arterial angiography in the quantification of proximal vertebral artery stenoses.

MATERIALS AND METHODS

A prospective blind study of 316 vertebral arteries was undertaken between 1996 and 1998. One hundred and fifty-eight patients with cerebrovascular disorders without cerebral hemorrhage were studied consecutively by frequency or amplitude color Doppler flow imaging and intra-arterial angiography. The lesions were quantified by morphological and hemodynamic criteria and classified into 6 groups: 0% 207 arteries; 1-29% 32 arteries; 30-49% 29 arteries; 50-69% 13 arteries; 70-99% 23 arteries; 100% 12 arteries.

RESULTS

Ten of the 12 occlusions were identified, the 2 false-negatives were due to 2 revascularized vessels. Moderate stenoses (<50%) were differentiated from tight stenoses (>50%) using hemodynamic criteria. The majority of false-negative stenoses (38) in the different groups were related to intrathoracic or very deep origin of the artery, anechogenic stenosis or a tortuous vessel. Stenoses greater than 70% were diagnosed in 71% of cases with a specificity of 99%. The kappa value was 0.80.

CONCLUSION

Duplex sonography should be proposed first in VB attacks or stroke to detect and quantify vertebral artery stenoses for surgery and angioplasty.

[Floating thrombus in the carotid]

The cardiogenic origin of stroke is often established on the basis of documented arrhythmia, computed tomographic evidence of cerebral ischemia, duplex Doppler findings ruling out an atheromatous carotid origin, and sometimes visualization of an intracavitary thrombus at transesophageal echocardiography. In case of a large thrombus as observed in our present patient, duplex Doppler provides an important means of visualizing the thrombus despite the lack of a parietal lesions suggestive of atheromatosis.

[Color Doppler ultrasonography of short para-optic ciliary arteries in vascular glaucoma]

PURPOSE

To study color Doppler imaging in orbital vessels, especially para-optic short ciliary arteries, in patients with vascular glaucoma.

PATIENTS AND METHODS

Twenty vascular normal or moderate elevated pressure glaucoma patients (6 with bilateral glaucoma, 9 with unilateral glaucoma et 5 with asymmetric glaucoma) underwent a color Doppler imaging (Accusson 128XP) in orbital arteries: common carotid, ophthalmic artery, central retinal artery, short para-optic ciliary arteries. Systolic and diastolic blood flow velocities were measured, and resistance index of Pourcelot and ratios between different parameters were calculated.

RESULTS

In patients with unilateral glaucoma, ratios of systolic velocities between para-optic ciliary artery and common carotid, and ratio of Pourcelot index between para-optic ciliary artery and ophthalmic artery were increased in glaucomatous eyes. And Pourcelot index were statistically significant increased in all glaucomatous patients of the study compared with normal subjects.

DISCUSSION AND CONCLUSION

Comparison of Pourcelot index and ratios between parameters makes color Doppler imaging more reliable, especially when analyse short para-optic ciliary arteries, which vascularize optic nerve. In these arteries Pourcelot index was increased in vascular glaucoma patients. Vascular risk factor should be taken into consideration in this form of glaucoma.

Introduction of the closed cranial window technique in gerbils and verification by observation of the effects of specific drugs

The exact mechanisms of cerebral arterial hypoxia are not perfectly defined. Our purpose is to adapt and validate, with drugs well known in rats and rabbits, a closed cranial window technique in gerbils. The method was used with seventeen gerbils to measure diameter changes of the pial arterioles under normoxia (after the topical application of agonists and antagonists of ATP-sensitive and Ca2+-dependent potassium channels), as well as under hypoxia. In normoxia, aprikalim (10(-6) M), a direct activator of ATP-sensitive potassium channels, increases the diameter of pial arterioles by 10+/-2% (N = 17). This effect is inhibited by glibenclamide (10(-6) M), but not affected by iberiotoxin (10(-6) M), a specific inhibitor of Ca2+-dependent potassium channels. The adenosine-induced dilation by 19+/-5% (N = 17) is reduced by 59+/-16% with iberiotoxin, by 33+/-23% with glibenclamide and inhibited by theophylline (10(-5) M). In hypoxia (15% O2), pial arteriole diameters are increased by 24+/-5% (N = 17) and partially decreased by the application of glibenclamide and iberiotoxin to 59+/-11% and 54+/-5%, respectively. These data are similar to those obtained in other species and validate the closed cranial window technique on gerbils. They indicate that, as for rats and rabbits, both ATP-sensitive and Ca2+-dependent potassium channels are present in gerbil pial vessels and play a role in hypoxia.

[Cervical deficit radiculopathy in 3 cases of vertebral artery dissection]

Three cases of extracranial vertebral artery dissections with upper limb peripheral motor deficit (C5-C6) are reported. Six similar cases were also found in the literature. Central neurological symptoms occurred in five of these nine cases, suggesting the diagnosis of dissection. The peripheral motor or sensorial deficit was strictly isolated in the four other cases, simulating radicular neuralgia due to discopathy or foraminal compression. In case of dissections, a precise analysis of pain is helpful to guide diagnosis; sharp, unbearable, continuous and extended neck pain without nocturnal paroxysms and posterior neck stiffness is typical. Analgesics or anti-inflammatory drugs are ineffective. Peripheral motor deficit is more common than sensory deficit. Recovery was complete in this series. In most cases, the radiculopathy appears to be due to cervical root compression in its extraforaminal course due to the dissection hematoma and rarely to radicular ischemia.

Reproducibility in ultrasonic characterization of carotid plaques

BACKGROUND AND PURPOSE

Echolucent carotid plaques compared with echogenic plaques could carry a significant risk of transient ischemic attacks and strokes, but the reproducibility of new ultrasonic methods has not yet been proved. The objective was to evaluate interobserver and intraobserver agreement in characterizing the carotid plaques studied by both B mode imaging and color Doppler imaging, which is the only ultrasonic method available for recognizing anechoic lesions.

METHODS

Fifty-three carotid plaques greater than 40% in diameter were selected from four centers and simultaneously analyzed by 9 observers. Five types of plaques were defined by their echo structure: class I = uniformly anechogenic, class II = predominantly hypoechogenic with >50% hypoechogenic area, class III = predominantly echogenic with >50% echogenic area, class IV uniformly echogenic, class V = unclassified plaques. The luminal surface was characterized as either 1 = regular, 2 = recess of more than 2 mm in depth and width, or 3 = unclassified. Agreement of these variables was calculated by using the kappa index, agreement proportion and an intraclass correlation coefficient.

RESULTS

Interobserver reproducibility was only fair for type I (kappa = 0.47) and for the luminal surface (class 1, kappa = 0.52 and class 2, kappa = 0.41). Agreement proportion was 0.51 in hypoechoic plaques and 0.64 in the determination of the regular surface. Mean intraobserver agreement was fair (kappa = 0.47 +/- 0. 1) for plaque echogenicity to good (kappa = 0.63 +/- 0.19) for surface.

CONCLUSION

This study shows that the semiquantitative classification, first developed by Gray-Weale, then by Nicolaides, could be improved, thus giving rise to a new outlook in the debated field of ulcerations.

Acute middle cerebral artery stroke and transcranial Doppler sonography

Five studies (Zanette et al., Stroke 1995;26:430-3; Pulci et al., JEMU 1991;12:190-5; Kuschner et al., Neurology 1991;41:109-13; Camerlingo et al., Acta Neurol Scand 1993;88:108-11; Kenton et al., Stroke 1997;28:1601-6) have validated the diagnostic and the prognostic value of Transcranial Doppler Sonography (TDS) at the onset of middle cerebral artery (MCA) strokes, but there is no large study and the interest of these investigations is often ignored. This report insists on the TDS methodological rules. It shows its value in the detection of MCA stenoses or occlusions (mainly from cardiac origin) and underlines its usefulness in evaluating therapeutical procedures and in defining hemodynamic consequences of tight internal carotid artery stenoses.

Extracranial and intracranial vertebrobasilar dissections: diagnosis and prognosis

OBJECTIVES

To compare the diagnosis and prognosis of extracranial versus intracranial vertebral artery dissections without intracerebral haemorrhage.

METHODS

Twenty two vertebral artery dissections were defined by intra-arterial angiography and classified in two groups: group 1, nine extracranial dissections (seven patients) and group 2, 13 intracranial dissections (nine patients), involving the basilar artery in five cases. Bilateral dissections were found in 38% of the population. Before angiography, all the patients had been investigated by continuous wave Doppler, colour coded Doppler, and transcranial Doppler. Mean follow up was 44 months.

RESULTS

The two most important symptoms of both dissections (81% of patients) were unbearable pain preceding stroke and progressive onset of stroke within a few hours. Severe ultrasonic abnormalities were present in 94% of the patients whereas specific ultrasonic signs (segmental dilation with eccentric channel) were rare (19%) in both groups. Major strokes and brainstem strokes represented respectively 67% and 78% in intracranial versus 43% and 29% in extracranial dissections. Severe sequelae (permanent disabling motor or cerebellar deficit) were more often associated with intracranial (44%) than with extracranial dissections (14%). No recurrence of dissection and no cerebral haemorrhage were found under heparin. Significant factors of poor outcome (P< 0.05) were the initial severity of the stroke and the bilateral location of dissections.

CONCLUSION

The combination of a pain and a progressive onset of the stroke, corroborated by ultrasonic findings, could have helped to recognise most of these types of dissections. Intracranial dissections have a poorer prognosis than extracranial dissections.

Detection of vertebrobasilar intracranial stenoses: transcranial Doppler sonography versus angiography

Vertebrobasilar intracranial stenoses seem to carry a higher risk of brain stem ischemia than proximal vertebral artery stenoses. Our aim was to assess the value of transcranial Doppler sonography versus angiography in detecting and quantifying these intracranial stenoses. All consecutive patients who underwent transcranial Doppler sonography prior to angiography from 1989 to 1994 and whose sonograms showed a stenosis of greater than 50% of one vertebral artery (21 cases) or of the basilar artery (eight cases) were included in the study. These patients were compared with 60 other consecutive stroke patients studied via transcranial Doppler sonography prior to normal vertebrobasilar angiography The transcranial Doppler sonographic criteria for stenosis were a peak systolic frequency shift greater than 2 KHz. A tight stenosis was identified by this pattern combined with direct and reverse low frequencies of high spectrum energy. The sensitivity of transcranial Doppler sonography using a peak systolic frequency shift in diagnosing stenoses reached 80% and its specificity was 97% if only atheromatous stenoses were considered. The main diagnostic failures concerned bilateral stenoses or contralateral occlusion, tandem lesions, and upper basilar artery stenosis. Transcranial Doppler sonography underestimated the degree of stenosis compared to angiography in 55% of the cases. We conclude that transcranial Doppler sonography is accurate in recognizing a stenosed vessel in the intracranial vertebrobasilar circulation, but if this finding will alter therapy, the examination must be complemented by magnetic resonance angiography.

Experimental and numerical models of acute intracranial hypertension and basilar artery blood flow velocity

A numerical model based on Navier-Stokes equations was used in conjunction with an experimental model in rabbits to study the effects of acute intracranial hypertension on basilar artery blood flow velocity. The hypertension was induced by pressure transmission via an epidural pressure sensor inserted into a parietal intracranial opening. A critical value of half of the diastolic arterial pressure for the intracranial cerebral pressure was determined by both numerical and experimental models. At this intracranial cerebral pressure level, the total input resistance and total input compliance, determined by the numerical model, exhibited an increase of 27% and 10%, respectively, and the tissular compliance a decrease of 25% from their physiologic baseline values. When the intracranial cerebral pressure reaches the level of the diastolic arterial pressure, a zero diastolic flow is observed into the cerebral vascular system. This study validates the theoretical model, which could be used in assessing intracranial cerebral pressure noninvasively in humans when O2 pressure can be stabilized.

Cerebral vasodilation capacity: acute intracranial hypertension and supra- and infra-tentorial artery velocity recording

This experiment is the first to compare cerebral vasomotor reactivity in the supra- and infra-tentorial regions in baseline conditions and during progressive acute intracranial hypertension. The increase in intracranial pressure was performed using liquid pressure transmission in two groups of 16 rabbits by elevating a saline infusion bottle connected to the subdural space. Cerebral microvessel dilation capacity was studied using acetazolamide arterial infusion during three stages of 20 min: at baseline conditions, with an intracranial pressure value equal to half the diastolic arterial pressure and with an intracranial pressure equal to the diastolic arterial pressure. The effects of acetazolamide in the basilar artery and in the carotid siphon were simultaneously monitored by transcranial Doppler sonography during all the experiments. The changes in cerebral vasomotor reactivity occurred with the same intensity and latency in both vascular compartments in baseline conditions. The maximum amplitude of changes happened 30 s later in the basilar artery than in the carotid siphon. When intracranial pressure was above half the diastolic arterial pressure, the vasomotor tone began to decrease in the carotid siphon which supplies a small region of the rabbit brain, whereas it was maintained in the basilar artery. This effect could be explained by brain tissue hypertension. Vasomotor reactivity had nearly disappeared in all the cerebral arteries investigated when intracranial hypertension was equal to the diastolic arterial pressure. These results show evidence of a direct and late effect of acute elevation of intracranial pressure on cerebral microvascular tone. This begins in the supra-tentorial region but there is an early local effect on the carotid siphon due to the brain tissue pressure.

Effect of subclavian syndrome on the basilar artery

Fifty-five patients with a permanent or intermittent subclavian steal syndrome demonstrated by continuous wave Doppler were included in a prospective study: 25 patients without vertebro-basilar symptoms, 8 symptomatic patients with defined vertebro-basilar symptoms and 22 with hemodynamic vertebro-basilar occurrences. The basilar artery velocity was recorded by Transcranial Doppler Sonography in baseline conditions, and after a hyperaemia test to the upper limb. A spontaneous, incomplete basilar steal was diagnosed in seven patients, and a complete basilar steal in one patient, (14.5% of the cases). After hyperaemia test, 18 other incomplete basilar steal were observed. The occurrence of a basilar steal was higher in the vertebro-basilar group (57% of the cases) especially in 7 of the 8 cases with defined vertebro-basilar symptoms; it was lower in the patients without vertebro-basilar occurrences (36% of the cases). This basilar steal was also seen in five of the six symptomatic patients with opposite vertebral artery stenosis above a 50% diameter. Transcranial Doppler Sonography could help to define a subgroup of subclavian steal syndrome with a high risk of strokes.

Ultrasonic features of extracranial carotid dissections: 47 cases studied by angiography

The purpose of this prospective study was to assess the value of continuous wave Doppler velocimetry, standard duplex scanning and color Doppler flow imaging in the diagnosis of carotid dissections. From 1975 to 1993, 42 patients (mean age, 44 +/- 14 years) were admitted to the University Hospital of Angers for a carotid dissection studied first by ultrasonography, then defined by angiography. Five cases were bilateral. Continuous wave Doppler examination revealed signs of severe obstruction of the carotid arteries in 96% of the cases (occlusion, extensive submandibular tight stenoses, significant slowdowns in the carotid and ophthalmic vessels, retrograde ophthalmic blood flow). Standard duplex scanning suggested dissection in 72% of the cases (tapering stenoses or occlusion, segmental ectasis, tubular vessel, peripheral residual channel, or rare irregular "membrane"). Color Doppler flow imaging suggested a dissection in 82% of the cases. This method has the advantage of underlining the peripheral channel, the double lumen, and the dissecting hematoma, which often is hypoechoic. The ultrasonic methods (continuous wave Doppler combined with color Doppler flow imaging) failed only when they are performed late and when moderate or segmental intrapetrosal dissections were present. These ultrasonic investigations would thus appear to be useful for early diagnosis of carotid dissections.

Concurrent changes in intracranial pressure, cerebral blood flow velocity, and brain energy metabolism in rabbits with acute intracranial hypertension

The relationship between intracranial pressure or cerebral perfusion pressure (CPP), cerebral blood flow, and brain energy failure is unpredictable throughout the development of acute intracranial hypertension. The purpose of the present study was to correlate intracranial pressure with cerebral blood flow velocities and brain energy metabolism in adult rabbits. The acute intracranial hypertension was achieved by pressure transmission. Transcranial Doppler wave-forms were obtained from the basilar artery for monitoring cerebral blood flow velocities. 31P-Magnetic resonance spectroscopy was used to assess brain energy metabolism. The diastolic blood flow velocity began to decrease significantly (34.5%) when the intracranial pressure was equal to half the diastolic arterial pressure for a CPP of 36 +/- 18 mmHg. Circulatory cerebral resistances increased significantly (55%) for the same value of CPP. Diastolic frequency was near zero when intracranial pressure approached diastolic arterial pressure (51 +/- 12 mmHg), corresponding to a CPP of 30 +/- 15 mmHg. At the same time, only a tendency for brain energy metabolism to decrease was observed. Consequently, transcranial Doppler sonography could be proposed for the follow-up of intracranial hypertension. Magnetic resonance spectroscopy could help to monitor these patients and could be especially proposed in case of high intracranial pressure (near diastolic arterial pressure). The joint use of these two methods would help in making appropriate therapeutic decision in humans.

99Tcm-HMPAO cerebral scintigraphy and transcranial pulsed Doppler in acute intracranial hypertension in rabbits

The purpose of this study was to compare transcranial Doppler sonography (TCD) and 99Tcm-HMPAO cerebral scintigraphy in detecting the effects of acute intracranial hypertension by pressure transmission using a previously validated model. In 20 New Zealand rabbits, cerebral blood flow velocities of basilar artery and carotid siphon were simultaneously monitored in baseline conditions and during acute intracranial hypertension by pressure transmission. This hypertension was induced by progressive steps of 5 mmHg, for a 5 min duration by elevating a saline infusion bottle connected to the subdural space. In baseline conditions, significant correlations were found between basilar artery resistive index and 99Tcm-HMPAO uptake in brain stem, r = 0.5 (p < 0.05) and posterior cerebral areas, r = 0.78 (p < 0.001). Severe intracranial hypertension equal to the diastolic arterial pressure with a cerebral perfusion pressure of 22.8 +/- 12.7 mmHg significantly decreased the basilar artery blood flow velocities and global 99Tcm-HMPAO cerebral uptake. At this level of intracranial pressure, few correlations between the two methods were observed. TCD detected relatively high blood-flow velocities in the carotid siphon appearing to result from proximal cerebral artery vasospasm. Transcranial pulsed Doppler provides data about haemodynamic changes such as hypoperfusion, vascular resistance increase in the basilar artery territory and vasospasm of the carotid siphon. 99Tcm-HMPAO scintigraphy, which has not yet been studied during intracranial hypertension, gave immediate information on local cerebral perfusion. Cerebral scintigraphy demonstrated a significant diffuse and heterogeneous decrease in cerebral blood flow, without dissociation between supratentorial and infratentorial territories, and tissue perfusion deficit owing to arterial vasospasm. TCD provides emergency investigation in patients with severe head injuries or hydrocephalus. 99Tcm-HMPAO complements TCD in cases of vasospasm and in determining an area of perfusion tissue deficit.

Effects of thiopental on middle cerebral artery blood velocities: a transcranial Doppler study in children

The effect of an intravenous injection of thiopental on middle cerebral artery blood velocities was assessed by transcranial pulsed Doppler monitoring in 20 children: ten head-injured patients and ten control subjects. Thiopental induced a moderate but immediate decrease of middle cerebral artery blood velocities in both groups; this variation was significant (P < 0.01) and more prolonged in the head-injured than in control patients. Transcranial Doppler ultrasonography thus appears to be suitable for monitoring children in intensive care units and could help to avoid the use of thiopental in patients with low cerebral artery blood flow velocity.

Acute intracranial hypertension and basilar artery blood flow velocity recorded by transcranial Doppler sonography: an experimental study in rabbits

The relationship between intracranial hypertension and basilar artery blood flow is not well known, and it is not yet definite that the reduction of cerebral flow depends on cerebral perfusion pressure rather than microvessel compression. The purpose of the study described here was to investigate the effect of acute intracranial pressure on the basilar flow velocity, the cerebral perfusion pressure, and the systemic arterial pressure. The basilar Doppler signal was recorded continuously in 24 New Zealand rabbits by transcranial pulsed Doppler method. The acute intracranial hypertension was induced by the progressive raising, in steps of 5 mmHg, of a saline infusion bottle connected to an epidural sensor. The intracranial hypertension induced a decrease in diastolic and mean flow velocities in the basilar artery, and an increase in the resistance index. Cerebral perfusion pressure was significantly correlated with flow parameters. The basilar diastolic flow began to decrease significantly from a 35-40 mmHg intracranial pressure and for a 37 mmHg + 20 SD cerebral perfusion pressure, without significant variation of arterial pressure. Diastolic flow dropped to zero for a 53 mmHg intracranial pressure and a 30 mmHg + 15 SD cerebral perfusion pressure. These results show that high intracranial pressure values are necessary for significantly reducing basilar artery blood flow. This effect, and the increase of circulatory cerebral resistance, occurred before significant changes in systemic arterial pressure.

[Analysis using transcranial Doppler of hemodynamic consequences in 58 severe obstructions of the internal carotid artery. Preliminary results]

The authors have analyzed by transcranial pulsed Doppler 50 patients with one or two obstructions of the internal carotid artery, divided in three groups: 19 tight stenoses, 23 obstructions and 8 bilateral tight stenoses. The haemodynamic consequences of these carotid obstructions was evaluated from the results of velocity in the intracerebral arteries, the resistance index and the pulsatility compared to a reference artery (PTI). The PTI seems the most sensitive. Compared with the resistance index, it permits to better define the patients prone to be the victims of a haemodynamic cerebro-vascular accident, and seems indicated before carotid surgery is contemplated.

Spinal cord compression related to vertebral osteonecrosis

The authors report 3 cases of spinal cord compression by vertebral collapse related to osteonecrosis. Two patients needed surgical decompression permitting pathological diagnosis. In the third case, osteonecrosis was ascertained by radiological evidence of an intravertebral vacuum phenomenon. Three etiologic factors were noticed: osteoporosis, corticotherapy, and radiotherapy. The relative frequency of neurologic complications in vertebral collapse related to osteonecrosis compared to those observed in osteoporosis is discussed.

[Spontaneous arteriovenous fistulas of the vertebral artery. Apropos of a case--review of the literature]

Spontaneous arteriovenous fistulae of the vertebral artery are rare (only 41 cases in French and English-language literature). Auscultation regularly discloses a cervical bruit which was found by systematic examination in 30 p. 100 of the cases. Otherwise, the fistula was revealed by unilateral pulsatile tinnitus (30 p. 100) or by a transient vertebro-basilar ischaemic accident (20 p. 100). The main complications, which occurred in 40 p. 100 of the cases, were ischaemic accidents in the vertebro-basilar territory and, primarily in children, heart failure. Prognosis seems to be governed by the patient's age at the time of diagnosis: 6 out of 7 cardiac complications occurred before the age of 10, and only 2 beyond the age of 50; in contrast, the duration and complexity of the fistula do not appear to be prognostic factors. Doppler examination of the neck and head, based on clinical findings, confirms the diagnosis and provides information on a possible blood steal. Arteriography by the arterial route is mandatory before surgery, but it also represents a first therapeutic measure (embolization, or even spontaneous obliteration of the fistula during the procedure, as seen in 4 cases). Asymptomatic forms, for which embolization and surgery may be postponed, can be monitored by ultrasounds.

[Vertebral osteonecrosis. Apropos of 3 cases, 1 complicated by spinal cord compression and 2 associated with another necrotic localization]

The authors report three cases of vertebral osteonecrosis which presented the phenomenon of intra-vertebral space. These patients had osteoporosis with vertebral compression. Two received steroid therapy. One case progressively developed spinal cord compression and the two other cases had an associated osteonecrosis (femoral head and talus). After reviewing the literature, the authors stress the relative frequency of neurological complications, in particular spinal cord compression (7 per cent).

[Chromatography of urinary amino-acid in bismuth encephalopathy (author's transl)]

The urinary excretion of amino-acid have been determined by ionic exchange chromatography for 10 cases of bismuth encephalopathy and for 15 normal controls. The ninhydrine positive constituant reported by Burns in 5 cases of encephalopathy has not been detected. We are thinking it may be related to the use of a rich amino-acid solution during perfusions. We did not find any significant difference between the urinary excretion of amino-acid average value to the two groups. We found an increase excretion when severe encephalopathy were observed. Separate analysis of individual amino-acid excretion showed the following results: i) average percent of tyrosine excretion is lower in controls as in encephalopathies; ii) among the different ratios tested only SER + THR)/TYR and VAL/TYR are different in the two groups.