Sang Hyun Suh

Stent-assisted coil embolization of intracranial wide-necked aneurysms

The endovascular treatment of cerebral aneurysms with coils poses significant technical challenges, particularly with respect to wide-necked aneurysms. We present the results of our initial experiences in using a stent for endovascular treatment of aneurysms, with an emphasis on potential applications, technical aspects, and associated complications. Twenty-three wide-necked aneurysms from 22 patients were treated during the 13-month study period. Seven patients presented with subarachnoid hemorrhage. Aneurysms were located at the internal carotid artery (n=14), the vertebral artery (n=3), the basilar artery (n=5), and the middle cerebral artery (n=1). A Neuroform stent2 was used for stent-assisted procedures. Premedication with antithrombotic agents was available for unruptured cases. Postprocedural antithrombotic medication was prescribed for all patients. Nineteen aneurysms were primarily stented, followed by coil placement. For five of these aneurysms, stenting was performed subsequent to failure of an attempt to frame with an initial coil. Stenting for the remaining four aneurysms was performed as a rescue procedure to prevent the migration of previously placed coils. Complete occlusion was obtained in ten aneurysms, nearly complete occlusion (95% or more occluded) in 11 aneurysms, and partial occlusion (less than 95% occluded) in one aneurysm. In one aneurysm, we failed to navigate the microcatheter into the aneurysmal sac through the interstices of the stent. Stent thrombosis was noted during the procedure in one patient. Hemorrhagic complication on the 25th day after the procedure was noted in one patient. No procedure-related complications were observed during the procedure or during follow-up in the remaining 20 patients, including seven patients who did not receive antithrombotic agents prior to endovascular treatment owing to recent subarachnoid hemorrhage. To overcome the technical limitation in the coiling of wide-necked aneurysms, stent-assisted coil embolization may be a technically feasible and relatively safe method, even though longer periods of follow-up are required.

Reconstructive endovascular treatment of ruptured blood blister–like aneurysms of the internal carotid artery

OBJECT Ruptured blood blister-like aneurysms (BBAs) of the internal carotid artery (ICA) are rare but carry a high rate of morbidity and mortality. Furthermore, BBAs are very difficult to treat surgically as well as endovascularly. The authors present their experience in treating BBAs with reconstructive endovascular methods. METHODS Nine ruptured BBAs in 9 consecutive patients (2 men and 7 women; mean age 50 years, range 42-57 years) were treated using reconstructive endovascular methods between January 2006 and November 2007. Treatment methods and angiographic and clinical outcomes were retrospectively evaluated. RESULTS All 9 BBAs were initially treated with stent-assisted coil (SAC) embolization. This was followed by a second stent insertion using the stent-within-a-stent (SWS) technique in 3, covered stent placement in 3, and SAC embolization alone in 3. All 3 patients who underwent SWS placement had excellent outcomes (Glasgow Outcome Scale Score 5) with complete angiographic resolution of the BBAs. There were no treatment-related complications in the SWS group. Two of the 3 patients who received covered stents had excellent outcomes (Glasgow Outcome Scale Score 5) and complete occlusion of the BBA was achieved. The remaining patient who received a covered stent died of ICA rupture during the procedure. Aneurysm regrowth without rebleeding occurred in the 3 patients who underwent SAC embolization. Two of the 3 recurrent BBAs were treated with coil embolization with a second stent insertion, and as a result these belonged to the SWS group. The other recurrent BBA was treated with a covered stent. Of the 8 surviving patients, 5 underwent SWS, and 3 underwent covered stent placement. All surviving patients had excellent outcomes during the clinical follow-up period (mean 11 months, range 4-26 months); complete BBA resolution and smooth reconstruction of the affected ICA segment was shown on follow-up angiography. CONCLUSIONS In the present study, the SWS and covered-stent techniques effectively prevented rebleeding and regrowth of the BBA without sacrifice of the ICA. The SWS and covered-stent techniques can be considered an alternative treatment option for BBAs in selected patients in whom ICA sacrifice is not feasible. Stent-assisted coiling alone seems insufficient to prevent BBA regrowth.

Clinical and angiographic follow-up of stent-only therapy for acute intracranial vertebrobasilar dissecting aneurysms.

BACKGROUND AND PURPOSE: Little has been known about the clinical and angiographic follow-up results of stent-only therapy for intracranial vertebrobasilar dissecting aneurysms (VBDA). The purpose of this study was to evaluate the feasibility, safety, clinical, and angiographic follow-up of stent-only therapy for VBDA. MATERIALS AND METHODS: Twenty-seven patients with 29 VBDAs (11 ruptured, 18 unruptured), not suitable for deconstructive treatment, underwent stent-only therapy. Feasibility, safety, clinical, and angiographic follow-up were retrospectively evaluated. Angiographic outcomes were compared between single-stent and multiple-stent groups. RESULTS: All attempted stent placements were successfully accomplished without any treatment-related complication. Of the 11 ruptured VBDAs, 4 were treated by single stents, 6 by double overlapping stents, and 1 by triple overlapping stents. Of the 18 unruptured VBDAs, 6 were treated by stents, and 12 by double overlapping stents. One patient with a ruptured VBDA, treated by single stent, had rebleeding and died. None of the remaining patients had posttreatment bleeding during follow-up (mean, 28 months; range, 7–50 months). Eight patients with ruptured VBDA and all patients with unruptured VBDA had excellent outcomes (modified Rankin Scale, 0–1). The remaining 2 patients with ruptured VBDA were moderately disabled because of the initial damage. Angiographic follow-up was available in 27 VBDAs, 4 to 42 months (mean, 12 months) after treatment. Follow-up angiograms revealed complete obliteration of the dissecting aneurysm in 12, partial obliteration in 12, stable in 1, enlargement in 1, and in-stent occlusion in 1. Angiographic improvement (complete or partial obliteration) was more frequent in the multiple-stent group (17/17) than in the single-stent group (7/9; P < .05). CONCLUSIONS: In this small series, stent-only therapy was safe and effective in the treatment of VBDAs that were not deemed suitable for treatment with parent-artery occlusion.

Outcomes and prognostic factors of intracranial unruptured vertebrobasilar artery dissection

Objective: We aimed to evaluate the long-term clinical outcomes and prognostic factors of symptomatic intracranial unruptured vertebrobasilar artery dissection (siu-VBD). Methods: A total of 191 patients (M:F = 127:64; median age, 46 years) with siu-VBD were treated between January 2001 and December 2008. Presentations, treatments, outcomes, and prognostic factors were retrospectively analyzed. Results: Clinical manifestations were ischemic symptoms with headache (n = 97) or without headache (n = 13) and headache without ischemic symptoms (n = 81). Forty-six patients (24.1%) underwent endovascular treatment. The remaining 145 patients (75.9%) were medically treated with anticoagulants (n = 49), antiplatelets (n = 48), or analgesics alone (n = 48). Clinical follow-up data were available in 178 patients (102 ischemic and 76 nonischemic) at 15 to 102 months (mean, 46 months). None of the siu-VBD hemorrhaged. All 76 patients without ischemic presentation had favorable outcomes (modified Rankin Scale, 0–1). Of the 102 patients with ischemic presentation, outcomes were favorable in 92 and unfavorable in 10 patients. Four patients died; 3 died of causes unrelated to VBD, and one died as a result of basilar artery (BA) dissection. Old age (odds ratio [OR] 1.099; 95% confidence interval [CI] 1.103–1.204; p = 0.042) and BA involvement (OR 11.886; 95% CI 1.416–99.794; p = 0.023) were independent predictors of unfavorable outcomes in siu-VBD with ischemic presentation. Conclusions: Clinical outcomes for siu-VBD were favorable in all patients without ischemic symptoms and in most patients with ischemic presentation. None of the siu-VBD caused subarachnoid hemorrhage. Old age and BA involvement were independent predictors of unfavorable outcome in siu-VBD with ischemic presentation.

Stent-assisted coil embolization followed by a stent-within-a-stent technique for ruptured dissecting aneurysms of the intracranial vertebrobasilar artery. Clinical article.

OBJECT A ruptured dissecting aneurysm of the vertebrobasilar artery (VBA-DA) is a well-known cause of acute subarachnoid hemorrhage (SAH) with a high rate of early rebleeding. Internal trapping of the parent artery, including the dissected segment, is one of the most reliable techniques to prevent rebleeding. However, for a ruptured VBA-DA not suitable for internal trapping, the optimal treatment method has not been well established. The authors describe their experience in treating ruptured VBA-DAs not amenable to internal trapping of the parent artery with stent-assisted coil embolization (SAC) followed by a stent-within-a-stent (SWS) technique. METHODS Eleven patients-6 men and 5 women with a mean age of 48 years and each with a ruptured VBA-DA not amenable to internal trapping of the parent artery-underwent an SAC-SWS between November 2005 and October 2007. The feasibility and clinical and angiographic outcomes of this combined procedure were retrospectively evaluated. RESULTS The SAC-SWS was successful without any treatment-related complications in all 11 patients. Immediate posttreatment angiograms revealed complete obliteration of the DA sac in 3 patients, near-complete obliteration in 7, and partial obliteration in 1. One patient died as a direct consequence of the initial SAH. All 10 surviving patients had excellent clinical outcomes (Glasgow Outcome Scale Score 5) without posttreatment rebleeding during a follow-up period of 8-24 months (mean follow-up 15 months). Angiographic follow-up at 6-12 months after treatment was possible at least once in all surviving patients. Nine VBA-DAs showed complete obliteration; the other aneurysm, which had appeared partially obliterated immediately after treatment, demonstrated progressive obliteration on 2 consecutive follow-up angiography studies. There was no in-stent stenosis or occlusion of the branch or perforating vessels. CONCLUSIONS The SAC-SWS technique seems to be a feasible and effective reconstructive treatment option for a ruptured VBA-DA. The technique may be considered as an alternative therapeutic option in selected patients with ruptured VBA-DAs unsuitable for internal trapping of the parent artery.

Management and Clinical Outcome of Acute Basilar Artery Dissection

BACKGROUND AND PURPOSE: There have been inconsistencies on the prognosis and controversies as to the proper management of acute basilar artery dissection. The aim of this study was to evaluate acute basilar artery dissection and its outcome after management. MATERIALS AND METHODS: A total of 21 patients (mean age, 53 years; range, 24–78 years) with acute basilar artery dissection were identified between January 2001 and October 2007. Clinical presentation, management, and outcomes were retrospectively evaluated. RESULTS: The patients presented with subarachnoid hemorrhage (n = 10), brain stem ischemia (n = 10), or stem compression sign (n = 1). Ruptured basilar artery dissections were treated by stent placement with coiling (n = 4), single stent placement (n = 3), or conservatively (n = 3). Of the patients treated with endovascular technique, 6 had favorable outcome (modified Rankin scale [mRS], 0–2) and the remaining patient, who was treated by single stent placement, died from rebleeding. All 3 conservatively managed patients experienced rebleeding, of whom 2 died and the other was moderately disabled. Unruptured basilar artery dissections were treated conservatively (n = 7) or by stent placement (n = 4). Of the patients with unruptured basilar artery dissection, 9 had favorable outcome and the remaining 2 patients, both of whom were conservatively managed, had poor outcome because of infarct progression. The group with the ruptured basilar artery dissection revealed a higher mortality rate than the group with the unruptured dissection (30% vs 0%). The group treated with endovascular means revealed more favorable outcome than the group that was treated with conservative measures (90.9% vs 50%). CONCLUSION: The ruptured basilar artery dissections were at high risk for rebleeding, resulting in a grave outcome. Stent placement with or without coiling may be considered to prevent rebleeding in ruptured basilar dissections and judiciously considered in unruptured dissections with signs of progressive brain stem ischemia.

Incidence and Risk Factors of Recurrence After Endovascular Treatment of Intracranial Vertebrobasilar Dissecting Aneurysms

Background and Purpose— The incidence and risk factors for recurrence after endovascular treatment of intracranial vertebrobasilar dissecting aneurysms (VBDAs) have not been studied. We aimed to evaluate the incidence and risk factors for recurrence after endovascular treatment of VBDAs. Methods— A total of 111 patients (mean age, 45±10 years) underwent endovascular treatment for 119 VBDAs (ruptured/unruptured=73:46). Incidence and risk factors for recurrence were retrospectively evaluated. Results— Sixty-two VBDAs were treated by a reconstructive technique by using 1 to 3 overlapping stents with or without coiling, and 57 VBDAs were treated by a deconstructive technique by using proximal occlusion or internal trapping at the dissected segment of the parent artery. Follow-up angiography was available for 97 VBDAs (81.5%) in 89 patients at 3 days to 48 months (median, 13 months) after treatment. There were 13 recurrences: 6 had rebleeding but 7 had no rebleeding. All 6 hemorrhagic recurrences had initially presented with a ruptured form. Ten recurrences were confirmed by angiography, but 3 recurrences with rebleeding did not receive follow-up angiography. The rate of post-treatment recurrence did not differ between reconstructive and deconstructive treatments. Involvement of the posterior inferior cerebellar artery origin (odds ratio=8.026; 95% confidence interval, 1.561 to 41.259; P=0.013) was the only independent risk factor for recurrence. Conclusions— There was a 13% recurrence after endovascular treatment of VBDAs. Posterior inferior cerebellar artery origin involvement was the only independent risk factor for recurrence after endovascular treatment of VBDAs.

Prediction of thrombolytic efficacy in acute ischemic stroke using thin-section noncontrast CT

Thin-section noncontrast CT (NCT) can detect thrombi in large arteries and can provide a measure of thrombus composition based on Hounsfield Units (HU). A study using polyethylene tubes as a model of intracranial arteries concluded that the HUs of platelet-rich thrombi are lower than those of erythrocyte-rich thrombi. Thrombus HUs were measured by NCT in 34 patients with acute ischemic stroke before thrombolysis. Thrombi with lower HU counts were resistant to thrombolytics.

Endovascular Coil Embolization of Aneurysms with a Branch Incorporated into the Sac

BACKGROUND AND PURPOSE: Because of the concern for occlusion of the incorporated branch artery, an aneurysm with a branch incorporated into the sac has been regarded as a contraindication for coiling. The aim of this study is to evaluate the feasibility, techniques, and clinical and angiographic outcomes of coiling for aneurysms with a branch incorporated into the sac. MATERIALS AND METHODS: The medical records and radiologic studies of 69 patients with 79 aneurysms having a branch incorporated into the sac (26 ruptured, 53 unruptured) were retrospectively reviewed and evaluated. RESULTS: Coiling was accomplished in 78 aneurysms in 68 patients but was suspended in 1 due to incorporated branch occlusion. The aneurysms were treated by using the following techniques: single-catheter (n = 37), multicatheter (n = 22), balloon-remodeling (n = 7), stent-assisted coiling (n = 6), and combined (n = 7). Postembolization angiography revealed the following: near-complete occlusion in 71 (89.8%), remnant neck in 4 (5.1%), and incomplete occlusion in 4 (5.1%) aneurysms. Procedure-related permanent morbidity and mortality rates were 5.8% (4/69) and 0%, respectively. All patients with unruptured aneurysms had a modified Rankin Scale (mRS) score of 0, except for 1 patient who had an mRS score of 3. Of the 26 patients with ruptured aneurysms, 18 had favorable outcome (mRS 0–2) but 8 had poor outcome (mRS 3–6). Follow-up angiography was available at least once at 6–50 months (mean, 15 months) in 55 aneurysms (69.6%), of which 45 showed stable or improved occlusion; 4, minor recurrences; and 6, major recurrences. All 6 major recurrent aneurysms were retreated without complication by using a single-catheter (n = 1), multicatheter (n = 2), or balloon-assisted technique (n = 3). CONCLUSIONS: With appropriate techniques, most aneurysms with a branch incorporated into the sac could be safely treated by coiling, with acceptable outcomes.

Cerebral computed tomography angiography using a low tube voltage (80 kVp) and a moderate concentration of iodine contrast material: a quantitative and qualitative comparison with conventional computed tomography angiography.

Objective:To investigate the feasibility of an 80-kVp protocol using a moderate concentration contrast material (MC-CM) for cerebral computed tomography angiography by comparison with a conventional 120-kVp protocol using a high concentration contrast material (HC-CM). Materials and Methods:Attenuation values and signal-to-noise ratios (SNRs) were determined in a head phantom for 2 tube voltages (80 and 120 kVp) and 2 different iodine concentration contrast materials (HC-CM and MC-CM). Among 90 consecutive patients, 45 patients were scanned with 120 kVp and 150 mAseff after administration of 70 mL of HC-CM (370 mg iodine [mgI]/mL), whereas the other 45 patients were scanned with 80 kVp and 370 mAseff after administration of 70 mL of MC-CM (300 mgI/mL). The Hounsfield units (HU) of the internal carotid artery T junction, SNR, contrast-to-noise ratio (CNR), subjective degree of arterial enhancement, image noise, sharpness of the cerebral arterial boundary, and overall diagnostic image quality were compared between the 2 groups. Results:The mean attenuation of the internal carotid artery T junction, SNR, and CNR was significantly higher in the 80 kVp with MC-CM group (379.2, 33.7, and 31.1 HU, respectively) than in the 120 kVp with HC-CM group (282.2, 31.1, and 27.2 HU, respectively). The 80-kVp protocol resulted in significantly higher score in arterial enhancement, sharpness of the cerebral arteries, and overall diagnostic image quality. The effective dose of 80 kVp (0.7 mSv) was 22.2% lower than that of 120 kVp (0.9 mSv). Conclusions:The use of 80 kVp with MC-CM improved arterial enhancement, SNR, and CNR and provided superior quality images using a smaller amount of iodine and a lower radiation dose than the conventional protocol of 120 kVp with HC-CM.