Albert Ho Yuen Chiu

Cerebral hyperperfusion after flow diversion of large intracranial aneurysms

Cerebral hyperperfusion syndrome has been proposed to be caused by rapidly increased blood flow into chronically hypoperfused parenchyma with resultant impaired autoregulation, and has been noted after clipping of intracranial aneurysms and carotid stenting. The occurrence of the syndrome after endovascular flow diversion, however, has not been previously described. A 52-year-old woman was admitted electively for flow diverter treatment of a recurrent ventral paraclinoid aneurysm arising within a dysplastic segment of the left internal carotid artery. During the immediate postprocedural period the patient was found to have confusion, right hemiparesis, facial droop and dysarthria, which resolved with blood pressure control. Subsequent CT perfusion on day 11 demonstrated mildly elevated cerebral blood flow, cerebral blood volume and permeability values in the left hemisphere.

Double-lumen arterial balloon catheter technique for Onyx embolization of dural arteriovenous fistulas: initial experience

Background Dural arteriovenous fistulas are vascular malformations with variable clinical symptoms that range in severity from completely asymptomatic to seizures, dementia, loss of vision and intracranial hemorrhage. Historically, surgical obliteration was the treatment of choice but, more recently, endovascular embolization has become the first-line treatment. The liquid embolic agent Onyx (ethyl vinyl copolymer) has become the agent of choice, but problems with reflux around the delivery microcatheter and inadvertent venous penetration have arisen. Methods and results We present six cases in which the double-lumen balloon microcatheter was used to transarterially embolize dural arteriovenous fistulas via injection of Onyx through the wire lumen. Depending on the individual pathology a venous balloon was also used in some cases. The advantages and disadvantages of the use of these devices are discussed. Conclusions We consider that the use of the double-lumen balloon technique for fistula embolization has the potential for reducing overall procedural times, procedural failures and catheter retention in certain situations. In such cases we would advocate this as a first-line technique. When lower profile, more navigable balloon catheters become available, this may become the standard of care.

Comparison of Arterial Closure Devices in Antegrade and Retrograde Punctures

Purpose: To compare the efficacy, primary failure rates, and complications for the Angio-Seal and Perclose closure devices in antegrade and retrograde common femoral artery (CFA) punctures during peripheral angioplasty procedures. Methods: A retrospective single-center analysis was conducted between April 2002 and June 2006 of all patients who had a CFA puncture and no other intervention planned during the same admission. Patients undergoing thrombolysis were excluded. Of 215 punctures in 191 patients, 123 closures in 97 patients (82 men; mean age 69.5 ± 10.4 years, range 41–93) were eligible for analysis. Of these, 49 punctures were antegrade and 74 were retrograde. An Angio-Seal device was used in 40 closures, while 83 punctures were closed with a Perclose device. Deployment outcomes and complications were compared between devices for each puncture direction and between antegrade and retrograde punctures. Results: Seventy-eight (63.4%) of the 123 closures reached the primary endpoint of complication-free progress to discharge, comprising 30 (61.2%) of the 49 antegrade closures and 48 (64.9%) of the 74 retrograde closures. There was no significant difference between the devices for the primary endpoint. Twenty-two (17.9%) attempted closures failed. Forty-one (33.3%) closures had a complication after the procedure, but none required further intervention. In antegrade closures, Angio-Seal had a significantly lower rate of primary failure (11.1% versus 38.7% for Perclose, p=0.038). Antegrade closures had a higher rate of primary failure (p<0.01); however, this did not translate into any significant differences in postprocedural complications. No significant differences in primary failure or complication rates were found between the devices when used in retrograde punctures. Conclusion: Angio-Seal had a lower rate of primary failure than Perclose in antegrade puncture closures. We believe this reinforces the need for larger studies to compare closure devices in antegrade punctures.

Commentary: The StarClose Vascular Closure Device in Antegrade and Retrograde Punctures: A Single-Center Experience

Purpose: To evaluate the StarClose device and compare its success rates in antegrade and retrograde puncture closures. Methods: A retrospective review of all StarClose deployments from April 2005 to July 2007 was performed in a single tertiary referral institution radiology department. In this time period, 143 StarClose devices were deployed in 132 patients (102 men; mean age 68±14 years). Of these, 40 (28%) were deployed after antegrade and 103 (72%) after retrograde common femoral arterial punctures. Hospital notes were reviewed to evaluate minor (managed conservatively with compression) and major (requiring surgical intervention) complication rates in the immediate postprocedure period and the following 24 hours. Late complications were also assessed. Results: There were 11 (7.7%) immediate failures of device deployment: 4/40 (10.0%) antegrade and 7/103 (6.8%) retrograde. Within these 11 punctures, 1 major complication occurred that required surgical retrieval of the device following a retrograde puncture. No other major and 12 (9.1%) minor complications occurred following the 132 successful StarClose deployments. No late complications were seen on clinical or radiological follow-up. The total major complication rate was 0.7% (1/143). The total minor complication rate was 15.4% (22/143): 9/40 (22.5%) following antegrade punctures and 13/103 (12.6%) following retrograde punctures. Conclusion: The StarClose device is associated with a low major complication rate. A higher rate of minor complications was observed following antegrade punctures but all were managed with simple compression. Prospective randomized trials comparing closure devices are needed to evaluate their relative efficacy and safety in antegrade and retrograde punctures.

Use of aspirin as sole oral antiplatelet therapy in acute flow diversion for ruptured dissecting aneurysms

Subarachnoid hemorrhage secondary to rupture of a circumferential dissecting aneurysm continues to be a treatment dilemma. Vessel sacrifice, when possible, continues to be the safest option but in certain cases this is not possible due to lack of collateral supply. In such cases, coil assisted endovascular flow diversion has become a potential option but the requirement for dual antiplatelet therapy in an unsecured intracranial aneurysm continues to raise concern. We present a 48-year-old man with a World Federation of Neurological Surgeons grade 5 subarachnoid hemorrhage, secondary to a ruptured intradural left vertebral artery dissecting aneurysm, who was treated successfully with a pipeline embolization device with Shield technology using aspirin and a single intravenous loading dose of abciximab. To our knowledge, this is the first case of an acute flow diversion performed using only aspirin as the sole oral antiplatelet agent.

Cost analysis of intracranial aneurysmal repair by endovascular coiling versus flow diversion: At what size should we use which method?

Flow diverters enable intracranial aneurysmal repair without the need to enter the aneurysm sac. Concerns, however, have been raised regarding the cost compared with coiling techniques. The aim of this study was to evaluate the relative costs for different aneurysm sizes to ascertain if different sizes are more cost‐effectively treated by a particular method.

CT perfusion in acute stroke calls: A pictorial review and differential diagnoses

CT perfusion is increasingly utilised in hyperacute stroke to facilitate diagnosis and patient selection for reperfusion therapies. This review article demonstrates eight examples of how CT perfusion can be used to diagnose stroke mimics and small volume infarcts, which can be easily missed on non‐contrast CT, and to suggest the presence of an ischaemic penumbra. Radiologists involved in stroke management must understand the importance of rapid imaging acquisition and be confident in the prospective interpretation of this powerful diagnostic tool as we move into a new era of hyperacute stroke care.

De novo cavernoma developing from an asymptomatic thalamic microhemorrhage.

Cavernomas are low-flow vascular lesions affecting approximately 0.5% of the population. Historically these have been considered congenital lesions, but numerous reports have demonstrated de novo formation. The phenomenon is well documented in patients with the familial disease form and after cranial radiotherapy, but outside of these circumstances there is scant evidence as to the potential etiology. The authors present a 5 year MRI series of a 56-year-old woman with no known risk factors demonstrating cavernoma formation and growth from previously normal brain. The patient was consistently asymptomatic during follow-up. Given the history and imaging findings, we propose that cavernomas can arise directly from angiogenic proliferation secondary to microhemorrhage from unrelated causes.

Reply to: Occipital artery: a not so poor artery for the embolization of lateral sinus dural arteriovenous fistulas with Onyx

We read with interest the technical note by Chiu et al 1 presenting their single center experience in the treatment of dural arteriovenous fistulas (dAVFs) using double-lumen balloon catheters for liquid embolic agent injection. This case series presents six cases of dAVFs (3 Cognard type IV; 2 type III; and 1 type IIa+b2) embolized through the middle meningeal artery (MMA) via a double-lumen compliant balloon (Scepter C; Microvention, Tustin, California, USA). This technique seems useful and effective. …

CT perfusion can delineate lacunar infarcts in acute stroke calls

Lacunar infarction accounts for approximately one quarter of all ischemic strokes but can be difficult to diagnose on noncontrast CT and clinical grounds.1 Diffusion-weighted imaging MRI has traditionally been considered the optimal modality for imaging confirmation1 but can be difficult to obtain acutely. CT perfusion has been increasingly used in hyperacute stroke and has shown promise in improving detection of lacunar infarcts.2 We present 4 patients in whom CT perfusion was performed using a 320-slice scanner (Aquilion ONE Vision, Toshiba, Japan) and Ultravist 370 (iopromide, Bayer, Switzerland) injected at 4 mL/s for 50 mL. Multiplanar reconstruction of perfusion data was performed using commercially available software (Vitrea 6.6.2036.1, Vital Images, Minnetonka, MN). Time from stroke onset to CT perfusion is presented in the table.