Endovascular treatment of unruptured cerebral aneurysms.

76 consecutive patients with 78 unruptured cerebral aneurysms underwent endovascular therapy from July 1999 to May 2004 in our institute. For the wide-necked aneurysms, the remodeling technique, double microcatheter technique, or stent-assisted coil embolization was used, while a parent artery occlusion or covered stent was applied for the giant or fusiform aneurysms. Immediate angiographical results demonstrated 33 complete occlusions, 26 neck remnants, and 14 dome fillings. Four cases were treated with parent occlusion or stenting only, and one case was not treated with embolization but with clipping due to the rupture of the aneurysm during coil embolization. Immediate angiographic findings demonstrated that in aneurysms between 5 to 10 mm, the rate of complete occlusion was 48%, that of neck remnants 33%, and that of dome fillings 27%. In aneurysms between 11 to 25 mm, the rate of complete occlusion was 14%, that of neck remnants 28%, and that of dome fillings was 58%. In the angiographic follow-up results, all aneurysms smaller than 5 mm showed complete occlusion. In aneurysms between 5 to 10 mm, 74% of the aneurysms showed complete occlusion, and 21% showed neck remnants, and 5% showed dome filling. In aneurysms between 10 to 24 mm, 25% showed complete occlusion, while 75% showed dome filling. The overall mortality rate was 0% and the morbidity rate was 3.7% (2 major strokes, 1 minor stroke) at 30-days after embolization. In the clinical follow-up study, one case of a large basilar tip aneurysm caused a fatal rupture 28 months after the initial embolization. Endovascular therapy was performed on the unruptured aneurysms and was found to be an acceptable treatment, except for durability in cases of large aneurysms.

Clinical results of percutaneous transluminal angioplasty and stenting for intracranial vertebrobasilar atherosclerotic stenoses and occlusions.

SUMMARY: Eighteen patients with intracranial vertebrobasilar stenosis and occlusion were treated by PTA or stenting. In 11 of 18 cases, only PTA was performed and in seven of 18 cases, we used stents. The mean stenosis before and after PTA/stenting was 82.8% and 22.3%, respectively. In 11 cases of PTA only, the stenotic rate decreased from 81.8% to 29.6%, while 85.0% of the stenotic rate remarkably reduced to 6.0% in seven cases of stenting. The 30 days morbidity and 30 days mortality rate were 5.5% and 5.5%, respectively. There was only one haemorrhagic complication (cerebellar haemorrhage) in cases of stenting, and no ischemic events during or after the procedures. Restenosis (more than 50% stenosis) occurred in four of 18 cases(22.2%) during mean followup period of 12 months. Two patients with VA occlusion before treatment, developed restenosis and reocclusion. Complete total occlusion seems to be a high-risk lesion and strict follow-up is required. In this study, PTA/stenting for intracranial vertebrobasilar artery stenosis or occlusion is an effective treatment, but strict indications may be required because procedure-related 30 days morbidity rate was 5.5% in addition to unclear natural history.

Technique and Clinical Results of Carotid Stenting under Distal Protection.

SUMMARY: We perfomed carotid artery stenting(CAS) in 215 patients from August 1997 to October 2003 mainly using the distal protection technique. Our technique and clinical results are described in this paper.

Analysis of Complications related to Endovascular Therapy for Dural Arteriovenous Fistulae.

SUMMARY: In this paper, we reviewed our cases of dural arteriovenous fistulae (dural AVFs) and analyzed periprocedural complications. In 157 procedures, we encountered 14 complications. Overall, complication rate of 9% was seen.We divided these complications into five subgroups such as cranial nerve palsy, coil-related trouble, thromboembolic complication, vessel perforation, and radiation-related trouble. There were five transient abducent nerve palsies in cases with cavernous sinus dural AVFs. There were two cases of coil unraveling and two cases of coil migration. In two cases, direct puncture of the internal jugular vein was performed to retrieve the unraveled coil by using dual microcatheter and guidewire snare technique. We encountered two thromboembolic complications. In one case, venous infarction was recognized after polyvinyl alcohol particle embolization. In two cases of vessel perforations, there were no new neurological deficits except one case with transient Gerstmann syndrome. In endovascular treatment of dural AVF, serious complications are rare and can be prevented if maximum attention is paid during the procedure.

Standard Technique of PTA/stenting for Atherosclerotic Intracranial Arterial Stenosis.

SUMMARY: PTA/stenting for the intracranial arteriosclerotic lesion is effective and novel treatment. Our standard technique to avoid serious complications, such as vessel rupture or acute occlusion was introduced in this paper.

Experimental polyvinyl alcohol core coil for a drug delivery system.

SUMMARY: We developed a new type of coil with a polyvinyl alcohol core (PVA-core coil) to absorb and release various types of biologically active materials, for the endovascular treatment of intracranial aneurysms. A 10 mm segment of the PVA-core coil was used in this study. PVAcore coils were immersed in basic fibroblast growth factor (b-FGF) solution. The PVA-core coil, which absorbed b-FGF in the PVA core, was named FGF-core coil. This coil gradually released b-FGF in the solution without b-FGF. In vitro study, FGF-core coils, PVA-core coils and unmodified coils were cultured with fibroblasts (NIH3T3) respectively and their surface was observed with scanning electron microscopy (SEM). In vivo study, each coils were inserted into the rat common carotid artery. Rats were sacrificed and the arterial lumen were histologically examined 14 days and 28 days after coil implantation. Electron microscopy findings demonstrated remarkable cellular adhesion to the surface of the FGF-core coils, while no adhesion to the surface of the PVA-core coils and unmodified coils was found. Histologically, remarkable cellular proliferation and wall thickness like neointimal hyperplasia was demonstrated in the implanted common carotid artery of the FGF-core coil group at 14 days and 28 days. On the other hand, these changes did not occur in PVA-core coil group and unmodified coil group.We suggest that FGF-core coils may be effective to induce fibrotic changes inside cerebral aneurysms.

Clinical results of stenting for cervical internal carotid stenoses.

SUMMARY: Total 89 patients with cervical ICA stenosis were treated by stenting. In 74 cases of stenting, we used our blocking balloon systems to prevent distal embolism. The morbidity and the mortality rate was 4.5% and 0%, respectively.Two(3%) of 74 cases showed distal embolism when blocking balloon catheter systems(BBCS) were used, while distal embolism occurred in four (27%) of 15 cases of stenting without BBCS. On diffusion- weighted MRI (DWI), hyperintense areas were detected in seven (47%) of 15 lesions when we used BBCS only during postdilatation. On the other hand, use of BBCS during predilatation as well as postdilatation reduced hyperintense areas on DWI, which were detected in three (25%) of 12 patients. Our blocking balloon catheter system is a useful device to reduce the risk of distal embolism, especially when we use it during not only postdilatation but predilatation.

Complications associated with stenting for cerebral arteries.

SUMMARY: We have experienced total 116 stenting for 102 of cranio-cephalic arteries and 14 of intracranial arteries including occlusive cerebrovascular diseases, aneurysms, and fistulas.Ten complications were encountered. Three were ischemic complication, four stent migration, two restenosis, and one aneurysmal perforation during coiling across the stent strut. The mechanism and preventive method of these complications were discussed in this paper.

Factors Leading to and Treatment of Aneurysmal Perforation during Coil Embolization. Analysis of 105 Consecutive Cases.

SUMMARY: It is important to know the characteristics of aneurysms that tend to cause perforation and treatment of these perforations to reduce the morbi/mortality of the endovascular treatment for intracranial aneurysms. Factors leading to aneurysmal perforation were analyzed from the view points of aneurysmal status (ruptured or unruptured), size and direction of aneurysmal dome from the parent artery and treatment of perforation during GDC embolization was discussed in 105 consecutive cases. Perforation occurred in three small aneurysms (less than 3 mm in diameter or depth) where the direction of the dome is the same as that of microcatheter advancement. Perforation occurred when a microcatheter was advanced to counteract catheter recoil caused by coil deployment. Haemorrhage occurred in all cases immediately following microcatheter and coil perforation into the subarachnoid space. In all cases, bleeding was controlled by deploying the coil so that it extended from the subarachnoid space back into the intraaneurysmal cavity. In two cases, surgical clipping was required to treat the incompletely obliterated aneurysm. No additional permanent neurological deficit occurred as a result of any of the three perforations. Special care should be taken during the embolization of small aneurysms (less than 3 mm in minimal diameter) where, owing to the shape of the lesion, or fixation of a microcatheter by the stent strut, the antegrade force of the canulating microcatheter is transmitted directly toward the aneurysm dome.

Indirect carotid cavernous fistula appeared after balloon embolization of direct CCF.

The authors describe a case of indirect carotid cavernous fistula (CCF) appearing five months after embolization for traumatic direct CCF, which was treated six months after the trauma. Long-term (six months) venous hypertension to the affected cavernous sinus due to direct CCF and cavernous sinus thrombosis following a balloon embolization were considered as an etiology of the de novo dural arteriovenous fistula. The recurrent symptoms of CCF are usually related to detached balloon disorder, but delayed recurrence may be caused by the de novo dural AVF, if the direct CCF was treated in the chronic state.

Combined surgery and endovascular stenting for basilar artery stenosis refractory to balloon angioplasty: technical case report.

The authors report a case of symptomatic basilar artery stenosis treated by stenting via the surgically exposed C1 vertebral artery. This case was initially treated by percutaneous transluminal angioplasty via a transfemoral route but resulted in unsatisfactory dilatation. Stenting via a transfemoral route also resulted in failure because of the coiling of the proximal vertebral artery. Direct puncture of the vertebral artery beyond the coiling portion was tried but a stent could not be delivered beyond the C2 vertebrae. Finally, the vertebral artery was surgically exposed between C1 and the occipital bone and a stent was introduced into the lesion from this portion under fluoroscopic control. The basilar artery was fully opened by stenting without new neurological deficits. Stenting of the basilar artery via a transfemoral route is not always possible even with newer generation stents if the vertebral artery has elongated tortuous curves. Combined surgery and endovascular stenting is one of the alternatives in such cases including our case.

Clinical results and problems of percutaneous transluminal angioplasty and stenting for extracranial internal carotid stenoses. Is the blocking balloon catheter system useful for prevention of distal embolism?

SUMMARY: 110 patients with extracranial ICA stenosis were treated by PTA or stenting. In 21 of 55 cases of only PTA and in 40 of 55 cases of stenting, we used our blocking balloon systems to prevent distal embolism. The morbidity and the mortality rates were 5.4% and 0%, respectively. There was only one embolic complication in cases of PTA or stenting where blocking balloon systems were used. In contrast, distal embolism occurred in 3 of 34 cases of PTA without blocking balloon systems (one symptomatic case) and in 4 of 15 cases of stenting without blocking balloon systems (3 symptomatic cases). Our blocking balloon catheter system is a useful device to reduce the risk of symptomatic distal embolism.

Endovascular treatment for intracranial atherosclerotic stenosis. Pitfalls and problems.

SUMMARY: Fourty-five cases of intracranial atherosclerotic stenoses greater than 70% for intradural lesions or 60% for extradural lesions were treated by PTA or stenting. The stenotic lesions were successfully dilated in 44/45 patients and future stroke was prevented during a mean 29 month follow-up period. Stenotic ratio significantly reduced in stent-treated group compared with PTA-treated group and stenting was effective for cases refractory to PTA, such as elastic recoil or restenosis. However, stenting had its own drawbacks, such as difficulty in delivery, migration, and acute thrombosis.

Treatment of restenosis after percutaneous transluminal angioplasty for internal carotid artery stenosis.

The efficacy of repeated percutaneous transluminal angioplasty (PTA) and carotid endarterectomy (CEA) was examined in patients with restenosis after PTA for carotid stenosis. After percutaneous transluminal angioplasty (PTA) for 63 cases of internal carotid stenoses 13 cases of restenosis appeared. They were treated by PTA or carotid endarterectomy. The treatment was chosen by the patient after explanation of each treatment. We initially treated seven patients by repeat PTA and six by carotid endarterectomy. The degree of stenosis improved from 82% to 30% on average after repeated PTA. However, one patient in the PTA group had restenosis, and carotid endarterectomy was then performed. The other cases also had restenosis and were treated by PTA. The six cases treated by carotid endarterectomy were successfully treated without difficulty. The success rate of PTA was 5/7 (71%) in the restenosis cases. Patients with a greater residual stenosis after initial PTA had significantly more frequent restenosis. Repeat PTA and CEA both appeared effective treatment for restenosis after initial PTA, although PTA had a restenosis rate similar to that of initial PTA.

Haemorrhagic complication following percutaneous transluminal angioplasty for carotid stenosis.

We report 2 cases with haemorrhagic complications following percutaneous transluminal angioplasty (PTA) for carotid stenosis. Computed tomography (CT) scanning of these cases demonstrated diffuse subarachnoid haemorrhage in 1 case, and intracerebral haemorrhage in the other case on the next day after PTA. In the latter case, we measured cerebral blood flow velocity and mean transit time with transcranial doppler (TCD) and dynamic CT scan, which demonstrated remarkable increases in the blood flow velocity and peak height, respectively. From these results, postoperative hyperperfusion was suggested to have caused haemorrhagic complications.

The strategy for internal carotid stenosis with thrombus.

SUMMARY: We report 3 cases of internal carotid artery (ICA) stenosis with thrombus. The initial symptom is transient ischemic attack (TIA) in 1 case, and cerebral infarction due to artery-to-artery embolism in 2 cases.We started anticoagulation and antiplatelet therapy after the angiography on admission in all cases. Carotid endarterectomy (CEA) was performed in 1 case after confirming the disappearance of the thrombus 1 month after the initial attack, although small cerebral embolic infarction happened during this period. In the other cases, percutaneous transluminal angioplasty (PTA) and stenting was performed using the protective technique about 2 weeks after the initial attack without embolic complication. Postoperative angiography showed sufficient dilatation. It seemed that PTA/stenting using the protection system was one of the alternatives for ICA stenosis with thrombus.

Measurement of the intracranial arterial wedge pressure in cases of acute cerebral arterial occlusion to determine the indication of intraarterial thrombolytic therapy.

SUMMARY: Wedge pressure of the occluded major cerebral artery (distal pressure beyond the occlusion) was measured to estimate the residual cerebral blood flow in thirteen patients with acute ischemic stroke. There existed the relationship that patients with higher wedge pressure tolerated longer ischemic insults than those with lower wedge pressure. Wedge pressure is measured with minimum time loss before starting thrombolytic therapy and may be a good indicator to estimate the brain tissue reversibility.

Endovascular Surgery for Internal Carotid Stenoses. Results of PTA vs. Stenting.

SUMMARY: This paper will overview our results of endovascular therapy (PTA or stenting) for cervical ICA stenosis and discuss the advantages and disadvantages of each treatment. 60 cases with 62 lesions were treated with PTA 68 times, while 36 cases with 37 lesions were treated with stenting 37 times. A total of 99 lesions were treated with PTA or stenting 105 times. In the PTA group arterial stenosis improved from 76.4% to 21%. In the stent group the stenosis improved from 82.3% to 8.3%. The morbidity rate was 2/60 (3.3%) in PTA group, although two cases had minor neurological deficits, while in stent treated group, morbidity rate was 1/36 (2.8%), although it showed one major neurological deficit. Mortality was 0% in each group. The restenosis rate in PTA group was 15/58 (26%), while it was 0/20 (0%) in stent treated group. Stenting brings significant reduction of stenosis and reduces the rate of restenosis compared to PTA. However, stenting has its own disadvantages such as hypotension and distal kinks when deployed in tortuous ICA stenosis.

Endovascular stent placement for cervical internal carotid artery aneurysm causing cerebral embolism: usefulness of neuroradiological evaluation.

We present a case of a cervical internal carotid artery aneurysm that caused cerebral embolism. This lesion was supposed to be a dissecting aneurysm due to blunt neck injury. The large aneurysm with intramural thrombus was treated with endovascular placement of a balloon-expandable stent. Both CT and MRI were useful for evaluating the size and characteristics of the aneurysmal wall. Intravascular ultrasound imaging was also useful for evaluation of the satisfactory stent deployment and identification of the neck of the aneurysm. We discuss effectiveness of endovascular stenting for cervical internal carotid artery aneurysm with intramural thrombus and the usefulness of a combination of the neuroradiological imaging before, during and after the interventional procedure.

Presumed intraventricular meningioma treated by embolisation and the gamma knife.

A 58-year-old woman with a presumed incidentally discovered meningioma in the left lateral ventricle was treated by superselective embolisation and gamma knife therapy. The diameter of the tumour was 40 mm, and its main feeding artery was the left lateral posterior choroidal artery. This vessel was embolised with microcoils. At 8 months following embolisation, the diameter of the tumour had decreased and was stable. The gamma knife was chosen as an adjuvant therapy for the further control 13 months after embolisation. Embolisation and gamma knife therapy may be an alternative treatment for meningiomas where surgical resection appears difficult.