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Biomedical subjects

François Guilbert

Publications and source records attributed to François Guilbert.

16 recordsLinked to original sources
PubMed2006

Generalized epilepsy and classic spike-wave discharges with unilateral thalamic lesions.

BACKGROUND: Idiopathic generalized epilepsy (IGE) is a heterogeneous condition with a predominantly genetic origin. Clinical hallmarks of IGE syndromes include generalized spike and wave discharges and normal results on brain imaging. OBJECTIVE: To describe 2 patients with clinical presentations compatible with IGE but whose imaging studies revealed unilateral thalamic lesions. DESIGN: Case reports. SETTING: University-affiliated hospitals. PATIENTS: Two 21-year-old patients (1 man and 1 woman). MAIN OUTCOME MEASURES: Magnetic resonance imaging findings. RESULTS: Magnetic resonance imaging unexpectedly revealed unilateral thalamic lesions. CONCLUSIONS: We recommend doing magnetic resonance imaging studies in patients with IGE, especially in refractory or atypical cases. In rare cases, clinical features compatible with IGE may be associated with structural thalamic or other lesions.

Adult↗
PubMed2006

Follow-up of treated aneurysms: the challenge of recurrences and potential solutions.

Angiographic recurrences after endovascular treatment of aneurysms with platinum coils are frequent, but hemorrhages are unusual. Recurrences are more frequent in patients with large wide-necked aneurysms, when the initial occlusion is incomplete, and when patients are treated after subarachnoid hemorrhage. Although many occur early on, they can appear years after treatment. None of the recent devices has been proven effective in improving long-term results. A rigorous scientific approach, including randomized trials, is imperative to forward progress in this field.

Angioplasty↗
PubMed2006

Endoluminal cryotherapy to prevent recanalization after endovascular occlusion with platinum coils.

PURPOSE: Endovascular embolization with platinum coils is sometimes followed by recanalization. The present study was undertaken to assess whether cryoablation of the endothelial lining could prevent recanalization after coil occlusion. MATERIALS AND METHODS: Recanalization rates of canine maxillary and vertebral arteries (n = 20) occluded with platinum coils with or without previous cryoablation (with temperatures of -40 degrees C to -45 degrees C for 90 seconds) were analyzed by angiography immediately and at 1 and 3 months in five animals. Pathologic recanalization and fibrosis was assessed at 3 months with use of a qualitative scoring system. Findings were compared with Mann-Whitney tests. RESULTS: Recanalization after coil occlusion occurred in 50% and 60% of cases with cryoablation at 1 and 3 months, respectively, compared with 100% without ablation (P = .012 and P= .029). There was no significant difference in pathologic scores (P = .348). The brachial plexus in the vicinity of vertebral arteries was injured by cryotherapy in three animals in which an ipsilateral neurologic deficit developed. CONCLUSIONS: Cryotherapy was moderately effective in the prevention of recanalization after coil occlusion. Deep nerve injury was excessive with the protocol used in the present study.

Aneurysm↗
PubMed2005

In situ beta-irradiation of a brain arteriovenous malformation model.

BACKGROUND AND PURPOSE: The treatment of large brain arteriovenous malformations (BAVMs) is challenging, and embolization alone is seldom curative. The study goal is to enhance the efficacy of arteriovenous malformation embolization by adding a beta-emitting isotope to the embolic agent. METHODS: The pig rete mirabile was used as a BAVM model. The body distribution of radioactivity was evaluated after selective rete injection of N-butyl,2-cyanoacrylate mixed with (131)I-lipiodol in 8 animals using immediate whole body gamma-scintigraphy. Activities within the whole rete mirabile and selected tissue samples were quantified with a gamma counter immediately after sacrifice. Two pigs were submitted to serial gamma-scintigraphies for 6 weeks to detect delayed isotope leaching. Long-term effects of in situ irradiation were evaluated using a mixture of 188Re/N-butyl,2-cyanoacrylate in 8 pigs. In 1 animal, autoradiography was performed to evaluate local rete mirabile distribution of the radioactivity. Seven pigs were injected with 188Re/glue in 1 rete mirabile and with glue only on the opposite side, and the degree of vascular occlusion of both sides was compared on histology at 2 (n=2) or 6 months (n=5). RESULTS: There was negligible activity outside the target. Radiation caused occlusion of vessels unreached by the glue itself but in the vicinity of the radioactive source in 5 of 7 rete mirabile. CONCLUSIONS: Selective deposition of a beta-emitter inside a BAVM model may be achieved by current embolization techniques. The adjunct use of an isotope may increase the efficacy of embolization.

Animals↗
PubMed2004

Role of the endothelial lining in recurrences after coil embolization: prevention of recanalization by endothelial denudation.

BACKGROUND AND PURPOSE: Endovascular treatment can improve the outcome of patients treated for ruptured intracranial aneurysms as compared with surgical clipping, but angiographic recurrences are frequent. Endothelial denudation before coil embolization may prevent recanalization and improve results of endovascular treatment. METHODS: We compared angiographic and pathological results 3 months after coil occlusion of paired canine arteries (n=16), with or without previous denudation of the endothelial lining using an endovascular device. The technique was then used to denude the neck of carotid venous pouch bifurcation aneurysms before coil embolization in 8 dogs, and the angiographic evolution at 12 weeks was compared with 7 control aneurysms treated by coiling only. Qualitative scoring systems were used to compare angiographic results with time and neointimal coverage at the neck of aneurysm after necropsy. The evolution of angiographic scores was analyzed using Wilcoxon signed rank tests whereas angiographic and neointimal scores of the 2 groups were compared using the Mann-Whitney test. RESULTS: All arteries embolized with platinum coils recanalized, whereas most arteries (12/16 or 75%) denuded before coil embolization remained occluded at 3 and 12 weeks (P<0.001). Aneurysms treated with coils without previous denudation tended to recur, with angiographic scores significantly worse at 12 weeks as compared with T(0) (P=0.015). Median angiographic and neointimal scores were significantly better at 12 weeks with endothelial denudation (P=0.011 and 0.026, respectively). CONCLUSIONS: Endothelial denudation can prevent recanalization after coil embolization.

Animals↗
PubMed2004

Surgical construction of an in vivo carotid siphon model to test neurovascular devices.

OBJECTIVE: We developed an animal model to evaluate vascular trauma induced by endovascular devices that are proposed for the treatment of cerebrovascular diseases. METHODS: The model was constructed in six domestic swine by elongating the common carotid artery using interpositional grafts. Balloon catheters (n = 3), stents (n = 2), and a snare were tested 9 to 13 days after surgery. Device performance was evaluated by angiography, macroscopic photography, and histopathological examination. RESULTS: Animals tolerated the surgical procedure well, and artificial siphons were thought to provide realistic conditions for device testing. Balloon catheters induced minimal trauma, whereas coronary stents caused severe spasm or thrombosis and extensive macroscopic changes. CONCLUSION: Construction of an in vivo siphon model is feasible and potentially useful for testing neurovascular devices.

Anastomosis, Surgical↗
PubMed2004

Lingual artery bifurcation aneurysms for training and evaluation of neurovascular devices.

We present a canine lingual artery bifurcation aneurysm and assess its value for training in endovascular techniques and testing new embolic agents. The experimental aneurysm described herein mirrors human bifurcation aneurysms, and with this model, we sought to reproduce endovascular technical difficulties. However, the lesions created in this canine model did not show angiographic or histologic evidence of aneurysmal recurrence. We conclude that this model may be useful for training in endovascular techniques, but because of the lack of sufficient aneurysmal recurrence, it is not suitable for evaluating new embolic agents.

Aneurysm↗
PubMed2003

Endovascular treatment of intracranial aneurysms with radioactive coils: initial clinical experience.

BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms is safe and effective but is associated with angiographic recurrences. Beta radiation prevents recanalization after coil embolization in experimental models. We wanted to assess the feasibility of using radioactive coil embolization to improve long-term results of endovascular treatment. METHODS: Platinum coils were ion-implanted with 0.13 to 0.26 microCi/cm of 32P. Forty-one patients aged 34 to 84 years with 44 aneurysms with a high propensity for recurrences were included. Radioactive coils were introduced into aneurysms to reach a target volumetric activity of 0.018 microCi/mm3. Nonradioactive coils were also used to ensure the same safety and the same angiographic results as the standard procedure. Angiographic results, procedure-related complications, and neurological events during follow-up were recorded. Angiographic follow-up data are available in 36 lesions 6 months after treatment. RESULTS: Forty of 44 aneurysms (91%) could be treated with radioactive coils. Target activities could be reached in 88% of lesions that could actually be coiled (35/40). Total activities ranged from 1.72 to 80.9 microCi, for a mean of 20.13+/-20.80 microCi. Procedure-related complications occurred in 7% of patients. Initial angiographic results were satisfactory (complete occlusions or residual necks) in 75% of lesions. Angiographic recurrences occurred in 11 (31%) of patients followed, within the expected range for standard coils. There was no complication from beta radiation during a mean follow-up period of 10 months. CONCLUSIONS: Radioactive coil embolization is feasible; target volumetric activities can be reached in most aneurysms considered for endovascular treatment.

Adult↗
PubMed2003

Long-term angiographic recurrences after selective endovascular treatment of aneurysms with detachable coils.

BACKGROUND AND PURPOSE: Our aim in this study was to assess the incidence and determining factors of angiographic recurrences after endovascular treatment of aneurysms. METHODS: A retrospective analysis of all patients with selective endosaccular coil occlusion of intracranial aneurysms prospectively collected from 1992 to 2002 was performed. There were 501 aneurysms in 466 patients (mean+/-SD age, 54.20+/-12.54 years; 74% female). Aneurysms were acutely ruptured (54.1%) or unruptured (45.9%). Mean+/-SD aneurysm size was 9.67+/-5.91 mm with a 4.31+/-1.97-mm neck. The most frequent sites were basilar bifurcation (27.7%) and carotid ophthalmic (18.0%) aneurysms. Recurrences were subjectively divided into minor and major (ideally necessitating re-treatment). The most significant predictors of angiographic recurrence were determined by logistic regression. These results were confirmed by chi2, t tests, or ANOVAs followed, when appropriate, by Tukey's contrasts. RESULTS: Short-term (< or =1 year) follow-up angiograms were available in 353 aneurysms (70.5%) and long-term (>1 year) follow-up angiograms, in 277 (55%), for a total of 383 (76.5%) followed up. Recurrences were found in 33.6% of treated aneurysms that were followed up and that appeared at a mean+/-SD time of 12.31+/-11.33 months after treatment. Major recurrences presented in 20.7% and appeared at a mean of 16.49+/-15.93 months. Three patients (0.8%) bled during a mean clinical follow-up period of 31.32+/-24.96 months. Variables determined to be significant predictors (P<0.05) of a recurrence included aneurysm size > or =10 mm, treatment during the acute phase of rupture, incomplete initial occlusions, and duration of follow-up. CONCLUSIONS: Long-term monitoring of patients treated by endosaccular coiling is mandatory.

Cerebral Angiography↗
PubMed2003

Feasibility of radioactive embolization of intracranial aneurysms using 32P-implanted coils.

BACKGROUND AND PURPOSE: Beta radiation can prevent recanalization after embolization. Our goal was to assess the feasibility of endovascular treatment of intracranial aneurysms using coils of a predetermined activity of 32P per centimeter. METHODS: We studied the total length of coils deployed into 357 intracranial aneurysms. Aneurysmal volumes were estimated using 3 mathematical models. We simulated that coils were implanted with 0.26 microCi/cm of 32P, calculated resulting volumetric activities, and compared them with "effective" levels derived from experimental data and "safe" levels prescribed for the clinical use of 32P in cystic craniopharyngiomas. RESULTS: Effective activities would have been reached in 92% to 98% of lesions had the coils been radioactive at the time of treatment. CONCLUSIONS: Radioactive coil embolization of aneurysms is feasible in most patients.

Adult↗
PubMed2003

High-concentration ethylene-vinyl alcohol copolymer and endovascular treatment of experimental aneurysms: feasibility of embolization without protection devices at the neck.

BACKGROUND AND PURPOSE: Coiling of intracranial aneurysms is both safe and effective but may be followed by recurrences. The purpose of this study was to assess the feasibility of endovascular treatment of aneurysms with high-concentration ethylene-vinyl alcohol copolymer (HCEVOH), without the use of protection devices at the neck. METHODS: Wide-necked bifurcation aneurysms with a high propensity for recurrences were constructed in 22 dogs. HCEVOH embolization was performed with a dedicated high-pressure microcatheter in 12 animals. Angiographic results at 3 and 12 weeks and pathologic results at 12 weeks were compared with those of a separate group of 10 animals treated with platinum coils. We used a qualitative scoring system to grade angiographic results, neointima formation, and recanalization at the neck. RESULTS: Intraaneurysmal HCEVOH injections could be performed without carotid emboli and without a protection device in 11 of 12 animals. Fragments detached upon traction of the microcatheters at the end of the procedure on two occasions. Immediate and late angiographic results were not significantly different between the two groups (P =.807), with a tendency for angiographic recurrences at 3 months (angiographic scores were significantly worse in both groups at 12 weeks as compared with T0 [P <.02]). A complete occlusion, including the neck, even at the cost of protrusion of material at the level of the branches, is necessary to decrease risks of recurrences. Neointima formation at the surface of the embolic agent was complete at the neck of aneurysms treated with HCEVOH. The neointimal score was significantly improved with HCEVOH as compared with coil embolization (P =.03). CONCLUSION: HCEVOH embolization of aneurysms without neck protection is feasible. It does not, however, eliminate recurrences in an experimental wide-necked aneurysm model.

Animals↗
PubMedDate not supplied

Endovascular treatment of experimental wide neck aneurysms: comparison of results using coils or cyanoacrylate with the assistance of an aneurysm neck bridge device.

BACKGROUND AND PURPOSE: Endovascular treatment of wide neck aneurysms often results in incomplete occlusion or aneurysm recurrence. The two goals of the present study were to compare results of coil embolization with or without the assistance of an aneurysm neck bridge device (ANBD) and to explore the use of this instrument to control cyanoacrylate embolization. METHODS: Wide necked bifurcation aneurysms were constructed in 28 dogs. Coil embolization of the aneurysms was performed 2 to 4 weeks later, with (n = 11) or without (n = 10) ANBD assistance. In seven other animals, embolization was performed with cyanoacrylate, injected under the protection of ANBDs. Angiographic results were compared immediately after and at 3 and 12 weeks. Neointima formation at the neck was also compared between groups at 12 weeks. RESULTS: Initial angiographic results and recurrences at 12 weeks were not significantly different in aneurysms coiled with or without ANBDs. Neointimal scores were also similar. The use of one ANBD at the neck was not sufficient to safely deliver cyanoacrylate into aneurysms. Cyanoacrylate embolization led to improved angiographic results (P =.05) and to better neointimal sealing of the neck of the aneurysms at 12 weeks (P =.004). CONCLUSION: ANBDs did not prevent recanalization and recurrences after coil embolization of wide neck aneurysms in this animal study. ANBD-assisted cyanoacrylate embolization was unsafe but could decrease recurrences at 12 weeks.

Animals↗