Takumi Asai

Relationship between low response to clopidogrel and periprocedural ischemic events with coil embolization for intracranial aneurysms

Objectives Low response to antiplatelet drugs is one of the risk factors for ischemic events. We examined the influence of low response to clopidogrel on symptomatic ischemic events and new ischemic MRI lesions with endovascular intracranial aneurysmal coil embolization. Materials and methods Between August 2010 and July 2013, 189 procedures in 181 consecutive patients who underwent endovascular coiling and received clopidogrel before treatment were investigated retrospectively. Platelet aggregation activity was examined by VerifyNow analysis. Low response to clopidogrel was defined as P2Y12 reaction units ≥230 in this study. Symptomatic ischemic complications within 30 days and postoperative new ischemic lesions on MRI–diffusion weighted imaging were evaluated. Results 66 of 189 (34.9%) cases were low responders to clopidogrel. Ischemic complications occurred in 2 of 66 (3.0%) low responders compared with 6 of 123 (4.9%) responders (p=0.72). A new high intensity spot larger than 5 mm was significantly more frequent in low responders (26 of 66; 39.4%) than in responders (26 of 121; 21.2%; p=0.01). On multivariate analysis, independent risk factors for larger new ischemic lesions were low response to clopidogrel, smokers, posterior location, and aneurysms with a larger neck. Conclusions Low response to clopidogrel had little effect on clinical outcome although it increased asymptomatic large ischemic lesions in this cohort.

Results and Current Trends of Multimodality Treatment for Infectious Intracranial Aneurysms

The authors retrospectively reviewed their cases of infectious intracranial aneurysms and discuss results and trends of current treatment modalities including medical, neurosurgical, and endovascular. Twenty patients (10 males and 10 females; mean age 46 years) with 23 infectious aneurysms were treated by various treatment modalities during a 15-year period. Fifteen cases (75.0%) were caused by infective endocarditis. Eleven aneurysms (47.8%) were ruptured. Two aneurysms (8.7%) presented a mass effect and 7 (30.4%) were unruptured and asymptomatic. The average aneurysm size was 6.5 ± 4.8 mm (range 1–22 mm). The aneurysms were located in proximal cerebral circulation in 7 (30.4%) and distal in 16 (69.6%). Six (26.1%) aneurysms were treated surgically (5: trapping, 1: neck clipping), 10 (43.5%) endovascularly (7: trapping, 2: proximal occlusion, 1: saccular coiling), and the remaining 7 (30.4%) medically. Endovascular treatment was gradually increased with time. Medical and surgical treatments were continuously performed during the study period. Surgery was preferred for the patient with intraparenchymal hematoma or treated by bypass surgery. Three periprocedural minor complications occurred in endovascular treatment. There was one postoperative infarction with permanent deficit developed from surgical treatment. During the follow-up period (mean 28.8 months), none of the aneurysms presented a recurrence or rebleeding. Thirteen patients (65.0%) had favorable clinical outcomes (modified Rankin Scale: 0–2), although four (20.0%) had poor outcomes (modified Rankin Score: 5–6). A multimodal approach for the management of infectious aneurysms achieved satisfactory results. Endovascular intervention is a feasible and efficacious treatment option and surgical intervention is still an indispensable procedure.

The ‘one and a half round microcatheterization technique’ for stent-assisted coil embolization of intracranial aneurysm: technical case series

Background Stent-assisted coil embolization is useful for wide-necked, large and giant aneurysms, and is effective for avoiding coil herniation. However, the mobility of the microcatheter is often restricted, resulting in deviated or unbalanced coiling. In order to prevent this insufficient coiling, the authors devised a method for microcatheterization, the ‘one and a half round microcatheterization technique’. This technique is based on the formation of a one and a half round loop by the microcatheter along the aneurysmal wall. Furthermore, this technique can be supplemented with the double-catheter technique. Methods From July 2010 to July 2012, the authors used this technique for 20 aneurysms in 20 patients (6 men and 14 women; mean age 61.7 years). The one and a half round microcatheterization technique was used alone in 12 cases and was supplemented with the double-catheter technique in eight. The clinical and angiographic results were retrospectively evaluated. Results The average aneurysm size was 16.7 mm; 12 aneurysms (60%) were located at the internal carotid artery, 5 (25%) at the basilar artery and 3 (15%) at the vertebral artery. Immediate angiographic results showed complete obliteration in 6 aneurysms (30%) and residual neck in 10 (50%), leaving 4 residual aneurysms (20%). This technique was useful and acceptably safe for packing the aneurysmal sac entirely. During an average follow-up of 20.5 months, 13 of the 18 aneurysms (72%) were stable or had improved, although 3 (16%) required retreatment. Conclusions The one and a half round microcatheterization technique provides dense coil packing for stent-assisted embolization of large or giant aneurysms.

Spinal cord infarction is an unusual complication of intracranial neuroendovascular intervention.

Spinal cord infarction is an unusual complication of intracranial neuroendovascular intervention. The authors report on two cases involving spinal cord infarction after endovascular coil embolization for large basilar-tip aneurysms. Each aneurysm was sufficiently embolized by the stent/balloon combination-assisted technique or double catheter technique. However, postoperatively, patients presented neurological symptoms without cranial nerve manifestation. MRI revealed multiple infarctions at the cervical spinal cord. In both cases, larger-sized guiding catheters were used for an adjunctive technique. Therefore, guiding catheters had been wedged in the vertebral artery (VA). The wedge of the VA and flow restriction may have caused thromboemboli and/or hemodynamic insufficiency of the spinal branches from the VA (radiculomedullary artery), resulting in spinal cord infarction. Spinal cord infarction should be taken into consideration as a complication of endovascular intervention for lesions of the posterior circulation.

Evaluation of the characteristics of various types of finishing coils for the embolization of intracranial aneurysms in an experimental model with radiolucent coils

In endovascular coil embolization of intracranial aneurysms, very soft coils, often called “finishing coils,” are usually selected in the final stage of coil embolization. The authors developed a radiolucent coil made of thin nylon thread to evaluate the performance of coils under a situation simulating the course of embolization. The characteristics of various types of finishing coils were investigated using radiolucent coils. Experimental embolization was performed with a silicone aneurysm filled with radiolucent coils simulating the final stage of embolization. Three indices, i.e. area, perimeter, and circularity of the inserted coils, were investigated on the X-ray images after coil insertion. The coils used were as follows: Target Ultra Helical, MicroPlex Hypersoft, Axium Helix, ED Coil Extrasoft, and DeltaPlush. In the analysis of area and perimeter, there were significant differences in multiple comparisons. There was no significant difference in circularity, although it was generally ranked in order by coil brand. Target Ultra and MicroPlex Hypersoft had higher scores for area and perimeter and lower scores for circularity, in contrast to DeltaPlush, which had lower scores for area and perimeter and a higher score for circularity. Based on these results, the finishing coils were divided into three groups: Target Ultra Helical and MicroPlex Hypersoft; Axium Helix and ED Coil Extrasoft; DeltaPlush. They are better for use in early, midst, and end of finishing, respectively. The characteristics of various finishing coils were evaluated, and the results obtained reflected actual clinical experience and provide useful information to appropriately select finishing coils.

Stent/Balloon Combination Assist Technique for Wide-Necked Basilar Terminal Aneurysms

We describe an enhanced endovascular procedure for the coiling of broad-necked basilar terminal aneurysms with a combined balloon/stent assist technique. A balloon-assisted catheter is inserted in the origin of one posterior cerebral artery (PCA) and an assisted stent is deployed from the opposite PCA to the basilar artery. A microcatheter for coiling is inserted through the stent strut (trans-cell approach), and the aneurysm is coiled under stent support and assisted balloon inflation to keep the patency of both PCAs. This technique is more beneficial for reducing the risk of stent deformity than Y-stenting, and it provides a simpler procedure than other advanced stent techniques. Additionally, it enables an easy approach when retreatment is necessary for aneurysm recurrence. This technique may be one of the useful procedures for embolizing broad-necked basilar terminal aneurysms safely and effectively.