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Endovascular treatment of intracranial aneurysms
Endovascular t r e a t m e n t of intracranial aneurysms
B r i a n M . T r e s s MD BS FRCR FRACR, P e t e r J. M i t c h e l l MB BS FRACR Department of Radiology, Universityof Melbourne, The Royal Melbourne Hospital, Grattan Street, Parkville,Victoria 3050, Australia
Journal of ClinicalNeuroscience1998, 5(2): 155-156
© Harcourt Brace & Co. Ltd 1998
In a previous 'Personal View' we surmised that Guglielmi Detachable Coil (GDC) techniques may rapidly b e c o m e the p r o c e d u r e of choice for the t r e a t m e n t of posterior fossa aneurysms, but that prospective r a n d o m i z e d trials were necessary. 1In 1995 a prospective, Oxford-based randomized multicentre trial (International Subarachnoid H a e m o r r h a g e T r i a l - 'ISAT') c o m p a r i n g conventional n e u r o s u r g e r y with endovascular GDC embolization in the t r e a t m e n t of acutely r u p t u r e d aneurysms commenced. Its results will n o t b e c o m e available until sufficient cases have b e e n accumulated, but the c o m b i n e d experience of endovascular techniques a r o u n d the world is sufficient to formulate a n u m b e r of statements relative to the present status of endovascular techniques and a n u m b e r of predictions. The techniques have proven themselves to be practical, achievable and relatively cheap. It should be r e m e m b e r e d that all of the promising initial results were obtained on patients who were considered unsuitable for surgery for reasons of p o o r clinical status, or because the a n e u r y s m was considered unclippable. T h e c o m b i n e d results f r o m eight interventional centres in the USA were recently reported. 2 Four h u n d r e d and three patients with acutely r u p t u r e d aneurysms were treated by GDC embolization after surgical exclusion. T h e c o m m o n e s t reasons for exclusion were anticipated surgical difficulty (69.2%), a t t e m p t e d surgery (12.7%) a n d p o o r neurological status (12.2%). Complete a n e u r y s m occlusion was achieved in 70.8% of small aneurysms with a small neck, 35% of large aneurysms and 50% of giant aneurysms. T h e r e was an i m m e d i a t e 8.9% morbidity related to the GDC technique. Seven deaths were attributed to technical complications (1.74%) and 18 (4.46%) to the severity of the p r i m a r y h a e m o r r h a g e . T h e Oxford g r o u p successfully treated 69 of 75 consecutive patients within 3 weeks of subarachnoid h a e m o r r h a g e , with p e r m a n e n t neurological deficits in three, and one death (4.8%). Glasgow o u t c o m e scores at 6 weeks were 53 grade 1, seven grade 2, four grade 3 and five grade 5. 3 M1 groups have f o u n d an inverse relationship between a n e u r y s m neck size and percentage occlusion? A c o m b i n a t i o n ofintravascular stents and GDC embolization has b e e n tried in experimentally m a n u f a c t u r e d wide-necked aneurysms in swine with some success, but e n o u g h technical p r o b l e m s were e n c o u n t e r e d to suggest that it is not yet ready for use in h u m a n subjects, s In the
posterior circulation GDC embolization has b e e n shown to be superior to balloon embolization and free coils in both the extent of aneurysm obliteration and in the incidence of complications. 6 Despite the technical success of this new technique, it is particularly p e r t i n e n t for interventional neuroradiologists to realize that the ultimate success of this f o r m of t r e a t m e n t for acutely r u p t u r e d aneurysms is still depend e n t u p o n the post-procedural medical m a n a g e m e n t of complications such as spasm or hydrocephalus. Thus, it may be predicted that, even if the technical success of endovascular techniques is equal to or superior to neurosurgery, there may not be a significant difference in patient o u t c o m e measures, unless immediate procedural morbidity is dramatically different. Even the cost savings will b e c o m e proportionately less obvious, because the patient's length of stay in hospital will be dictated by the natural history of b l o o d in the subarachnoid space. O n the other h a n d the cost benefit of electively treating u n r u p t u r e d aneurysms should be starkly a p p a r e n t when the abbreviated length of hospital stay required by endovascular techniques is a d d e d to the savings achieved through lack of n e e d for a full operating staff, general anaesthesia and intensive care. As the results of the Oxford trial will n o t be available for at least 2 years, what should the c u r r e n t policy in relation to aneurysm t r e a t m e n t be? A strong case can be m a d e that aneurysms of the vertebrobasilar circulation should be treated in the first instance by endovascular techniques. In fact, there has b e e n a significant p r o b l e m in prospective randomization of patients with posterior fossa circulation aneurysms in the Oxford-based trial because of b o t h surgeons' and patients' preference for the endovascular method. The policy in respect to aneurysms in the anterior circulation should be u n c h a n g e d p e n d i n g the trial results. An educated prediction is that m a n y of these aneurysms will best be treated by the endovascular route and that is what the patients themselves will prefer, given the choice of what amounts to an extension of their diagnostic angiogram versus craniotomy and e x t e n d e d aftercare. We have previously concluded that the interventional neuroradiologist, working in close collaboration with neurosurgical colleagues, is the most appropriately trained specialist to p e r f o r m endovascular aneurysm embolizations. 1 It has b e e n argued elsewhere that the
J. C/in. Neuroscience
Volume 5 Number 2 April 1998
155
A personal view interventionist should be assigned beds and be responsible for the total m a n a g e m e n t of the aneurysm patient. There are even stronger arguments against this proposition. Interventional neuroradiologists in most parts of the world also p e r f o r m diagnostic examinations, which consume m u c h of the remainder of the working week. They are relatively few in number. They are not formally trained in the medical m a n a g e m e n t of subarachnoid h a e m o r r h a g e and its complications. The professional Colleges of Radiology should anticipate and support specialized training for interventional neuroradiologists. An Australian NH&MRC subcommittee recently considered the demographic data required as the m i n i m u m to support an interventional radiology centre. It r e c o m m e n d e d that a population referral base of 2 million was the m i n i m u m required. A m i n i m u m of two trained interventional neuroradiologists is necessary, both to cover absences and to work together in some of the more difficult and d e m a n d i n g procedures. Training positions should be immediately established to ensure adequate numbers of skilled interventional neuroradiologists into the future. G o v e r n m e n t funding will be necessary in most instances.
Endovascular treatment of aneurysms Correspondence and offprint requests: ProfessorBrian Tress, University of Melbourne, Department of Radiology,The Royal Melbourne Hospital, Grattan Street, Parkville, Victoria 3050, Australia, Tel: 61 3 9342 7255, Fax: 61 3 9342 8369 References
Received3 September1997; Accepted 12 September1997
156
J. Clin. Neuroscience Volume 5 Number 2 April 1998
1. Tress BM, Mitchell PJ. Endovascular treatment of intracranial aneurysms. J Clin Neuroscience 1995; 2: 24-25. 2. Vinuela E Duckwiler G, Mawad M. Guglielmi detachable coil embolization of acute intracranial aneurysm: perioperative anatomical and clinical outcome in 403 patients.J Neurosurg 1997; 86: 475-482. 3. ByrneJV, Molyneux AJ, Brennan RP, Renowden SA. Embolisation of recently ruptured intracranial aneurysms. J Neurol Neurosurg Psychiatry 1995; 59: 616-620. 4. Fernandez-Zubillaga A, Guglielmi G, Vinuela F, Duckwiler GR. Endovascular occlusion of intracranial aneurysms with electrolytically detachable coils: correlation of aneurysm neck size and treatment results. AmJ Neuroradiol 1994; 15: 815-820. 5. Massoud TF, Turjman,JIC, Vinuela F, Guglielmi G, Gobin YP, Duckwiler GR. Endovascular treatment of fusiform aneurysms with stents and coils: technical feasibility in a swine model. AmJ Neuroradiol 1995; 16: 1953-1963. 6. Picard L, Bracard S, Lehericy Set al. Endovascular occlusion of aneurysms of the posterior circulation: comparison of balloons, free coils and detachable coils in 38 patients. Neuroradiology 1996; 38; Suppl 1: S133-141.
B r i a n M . T r e s s MD BS FRCR FRACR, P e t e r J. M i t c h e l l MB BS FRACR Department of Radiology, Universityof Melbourne, The Royal Melbourne Hospital, Grattan Street, Parkville,Victoria 3050, Australia
Journal of ClinicalNeuroscience1998, 5(2): 155-156
© Harcourt Brace & Co. Ltd 1998
In a previous 'Personal View' we surmised that Guglielmi Detachable Coil (GDC) techniques may rapidly b e c o m e the p r o c e d u r e of choice for the t r e a t m e n t of posterior fossa aneurysms, but that prospective r a n d o m i z e d trials were necessary. 1In 1995 a prospective, Oxford-based randomized multicentre trial (International Subarachnoid H a e m o r r h a g e T r i a l - 'ISAT') c o m p a r i n g conventional n e u r o s u r g e r y with endovascular GDC embolization in the t r e a t m e n t of acutely r u p t u r e d aneurysms commenced. Its results will n o t b e c o m e available until sufficient cases have b e e n accumulated, but the c o m b i n e d experience of endovascular techniques a r o u n d the world is sufficient to formulate a n u m b e r of statements relative to the present status of endovascular techniques and a n u m b e r of predictions. The techniques have proven themselves to be practical, achievable and relatively cheap. It should be r e m e m b e r e d that all of the promising initial results were obtained on patients who were considered unsuitable for surgery for reasons of p o o r clinical status, or because the a n e u r y s m was considered unclippable. T h e c o m b i n e d results f r o m eight interventional centres in the USA were recently reported. 2 Four h u n d r e d and three patients with acutely r u p t u r e d aneurysms were treated by GDC embolization after surgical exclusion. T h e c o m m o n e s t reasons for exclusion were anticipated surgical difficulty (69.2%), a t t e m p t e d surgery (12.7%) a n d p o o r neurological status (12.2%). Complete a n e u r y s m occlusion was achieved in 70.8% of small aneurysms with a small neck, 35% of large aneurysms and 50% of giant aneurysms. T h e r e was an i m m e d i a t e 8.9% morbidity related to the GDC technique. Seven deaths were attributed to technical complications (1.74%) and 18 (4.46%) to the severity of the p r i m a r y h a e m o r r h a g e . T h e Oxford g r o u p successfully treated 69 of 75 consecutive patients within 3 weeks of subarachnoid h a e m o r r h a g e , with p e r m a n e n t neurological deficits in three, and one death (4.8%). Glasgow o u t c o m e scores at 6 weeks were 53 grade 1, seven grade 2, four grade 3 and five grade 5. 3 M1 groups have f o u n d an inverse relationship between a n e u r y s m neck size and percentage occlusion? A c o m b i n a t i o n ofintravascular stents and GDC embolization has b e e n tried in experimentally m a n u f a c t u r e d wide-necked aneurysms in swine with some success, but e n o u g h technical p r o b l e m s were e n c o u n t e r e d to suggest that it is not yet ready for use in h u m a n subjects, s In the
posterior circulation GDC embolization has b e e n shown to be superior to balloon embolization and free coils in both the extent of aneurysm obliteration and in the incidence of complications. 6 Despite the technical success of this new technique, it is particularly p e r t i n e n t for interventional neuroradiologists to realize that the ultimate success of this f o r m of t r e a t m e n t for acutely r u p t u r e d aneurysms is still depend e n t u p o n the post-procedural medical m a n a g e m e n t of complications such as spasm or hydrocephalus. Thus, it may be predicted that, even if the technical success of endovascular techniques is equal to or superior to neurosurgery, there may not be a significant difference in patient o u t c o m e measures, unless immediate procedural morbidity is dramatically different. Even the cost savings will b e c o m e proportionately less obvious, because the patient's length of stay in hospital will be dictated by the natural history of b l o o d in the subarachnoid space. O n the other h a n d the cost benefit of electively treating u n r u p t u r e d aneurysms should be starkly a p p a r e n t when the abbreviated length of hospital stay required by endovascular techniques is a d d e d to the savings achieved through lack of n e e d for a full operating staff, general anaesthesia and intensive care. As the results of the Oxford trial will n o t be available for at least 2 years, what should the c u r r e n t policy in relation to aneurysm t r e a t m e n t be? A strong case can be m a d e that aneurysms of the vertebrobasilar circulation should be treated in the first instance by endovascular techniques. In fact, there has b e e n a significant p r o b l e m in prospective randomization of patients with posterior fossa circulation aneurysms in the Oxford-based trial because of b o t h surgeons' and patients' preference for the endovascular method. The policy in respect to aneurysms in the anterior circulation should be u n c h a n g e d p e n d i n g the trial results. An educated prediction is that m a n y of these aneurysms will best be treated by the endovascular route and that is what the patients themselves will prefer, given the choice of what amounts to an extension of their diagnostic angiogram versus craniotomy and e x t e n d e d aftercare. We have previously concluded that the interventional neuroradiologist, working in close collaboration with neurosurgical colleagues, is the most appropriately trained specialist to p e r f o r m endovascular aneurysm embolizations. 1 It has b e e n argued elsewhere that the
J. C/in. Neuroscience
Volume 5 Number 2 April 1998
155
A personal view interventionist should be assigned beds and be responsible for the total m a n a g e m e n t of the aneurysm patient. There are even stronger arguments against this proposition. Interventional neuroradiologists in most parts of the world also p e r f o r m diagnostic examinations, which consume m u c h of the remainder of the working week. They are relatively few in number. They are not formally trained in the medical m a n a g e m e n t of subarachnoid h a e m o r r h a g e and its complications. The professional Colleges of Radiology should anticipate and support specialized training for interventional neuroradiologists. An Australian NH&MRC subcommittee recently considered the demographic data required as the m i n i m u m to support an interventional radiology centre. It r e c o m m e n d e d that a population referral base of 2 million was the m i n i m u m required. A m i n i m u m of two trained interventional neuroradiologists is necessary, both to cover absences and to work together in some of the more difficult and d e m a n d i n g procedures. Training positions should be immediately established to ensure adequate numbers of skilled interventional neuroradiologists into the future. G o v e r n m e n t funding will be necessary in most instances.
Endovascular treatment of aneurysms Correspondence and offprint requests: ProfessorBrian Tress, University of Melbourne, Department of Radiology,The Royal Melbourne Hospital, Grattan Street, Parkville, Victoria 3050, Australia, Tel: 61 3 9342 7255, Fax: 61 3 9342 8369 References
Received3 September1997; Accepted 12 September1997
156
J. Clin. Neuroscience Volume 5 Number 2 April 1998
1. Tress BM, Mitchell PJ. Endovascular treatment of intracranial aneurysms. J Clin Neuroscience 1995; 2: 24-25. 2. Vinuela E Duckwiler G, Mawad M. Guglielmi detachable coil embolization of acute intracranial aneurysm: perioperative anatomical and clinical outcome in 403 patients.J Neurosurg 1997; 86: 475-482. 3. ByrneJV, Molyneux AJ, Brennan RP, Renowden SA. Embolisation of recently ruptured intracranial aneurysms. J Neurol Neurosurg Psychiatry 1995; 59: 616-620. 4. Fernandez-Zubillaga A, Guglielmi G, Vinuela F, Duckwiler GR. Endovascular occlusion of intracranial aneurysms with electrolytically detachable coils: correlation of aneurysm neck size and treatment results. AmJ Neuroradiol 1994; 15: 815-820. 5. Massoud TF, Turjman,JIC, Vinuela F, Guglielmi G, Gobin YP, Duckwiler GR. Endovascular treatment of fusiform aneurysms with stents and coils: technical feasibility in a swine model. AmJ Neuroradiol 1995; 16: 1953-1963. 6. Picard L, Bracard S, Lehericy Set al. Endovascular occlusion of aneurysms of the posterior circulation: comparison of balloons, free coils and detachable coils in 38 patients. Neuroradiology 1996; 38; Suppl 1: S133-141.