Gabor Toth

Posterior circulation flow diversion: a single-center experience and literature review

Background Flow diverters have been used predominantly for large anterior circulation aneurysms. Data on the safety and efficacy of this treatment for posterior circulation aneurysms are limited. Objective To present our posterior circulation flow diverter experience, outcomes and morbidity in comparison with recent studies. Methods A retrospective chart and imaging review of six patients with seven aneurysms in posterior circulation vessels, treated with flow diverter technology was carried out. A literature review was performed using standard online search tools. Results We included five saccular and two fusiform posterior circulation aneurysms. An average of two flow diverters was placed for each patient. Adjunctive coiling was used in three cases. Follow-up at an average of 14.5 months showed complete angiographic occlusion in 4 (57.1%) cases, including one patient with in-stent thrombosis and major brainstem stroke at 4.5 months, a week after self-discontinuing dual antiplatelet therapy. Two other patients developed small periprocedural strokes but had excellent recovery. One death occurred 18 months after the initial procedure. No aneurysm rupture or parenchymal hemorrhage was seen. Overall, 5 (71%) cases, all with saccular aneurysms, had good clinical outcome (modified Rankin score (mRS) 0–1). Fusiform basilar aneurysms had markedly worse outcomes (mRS 5 and 6). Our literature review yielded six other studies with 100 additional patients. Overall, good outcome was seen in 74.3%, with a 12.3% average mortality and 11% permanent neurologic deficit rate. Complete occlusion varied from 43% to 100%. Conclusions Flow diversion may be a possible treatment in carefully selected patients with high-risk atypical posterior circulation aneurysms, with poor natural history and no optimal treatment strategy. Symptomatic and fusiform large aneurysms appear to carry the highest risk. Further studies are necessary to assess the role of flow diversion in the posterior circulation.

Addition of Hyperacute MRI Aids in Patient Selection, Decreasing the Use of Endovascular Stroke Therapy

Background and Purpose— The failure of recent trials to show the effectiveness of acute endovascular stroke therapy (EST) may be because of inadequate patient selection. We implemented a protocol to perform pretreatment MRI on patients with large-vessel occlusion eligible for EST to aid in patient selection. Methods— We retrospectively identified patients with large-vessel occlusion considered for EST from January 2008 to August 2012. Patients before April 30, 2010, were selected based on computed tomography/computed tomography angiography (prehyperacute protocol), whereas patients on or after April 30, 2010, were selected based on computed tomography/computed tomography angiography and MRI (hyperacute MRI protocol). Demographic, clinical features, and outcomes were collected. Univariate and multivariate analyses were performed. Results— We identified 267 patients: 88 patients in prehyperacute MRI period and 179 in hyperacute MRI period. Fewer patients evaluated in the hyperacute MRI period received EST (85 of 88, 96.6% versus 92 of 179, 51.7%; P<0.05). The hyperacute-MRI group had a more favorable outcome of a modified Rankin scale 0 to 2 at 30 days as a group (6 of 66, 9.1% versus 33 of 140, 23.6%; P=0.01), and when taken for EST (6 of 63, 9.5% versus 17 of 71, 23.9%; P=0.03). On adjusted multivariate analysis, the EST in the hyperacute MRI period was associated with a more favorable outcome (odds ratio, 3.4; 95% confidence interval, 1.1–10.6; P=0.03) and reduced mortality rate (odds ratio, 0.16; 95% confidence interval, 0.03–0.37; P<0.001). Conclusions— Implementation of hyperacute MRI protocol decreases the number of endovascular stroke interventions by half. Further investigation of MRI use for patient selection is warranted.

A Mobile Stroke Treatment Unit for Field Triage of Patients for Intraarterial Revascularization Therapy.

Favorable outcomes in intraarterial therapy (IAT) for acute ischemic stroke (AIS) are related to early vessel recanalization. The mobile stroke treatment unit (MSTU) is an on‐site, prehospital, treatment team, laboratory, and CT scanner that reduces time to treatment for intravenous thrombolysis and may also shorten time to IAT.

Retrievable stents, “stentrievers,” for endovascular acute ischemic stroke therapy

Endovascular therapy for acute ischemic stroke continues to evolve to improve both efficacy and safety. In the late 1990s, intra-arterial chemical thrombolysis with prourokinase was shown to be effective in achieving partial recanalization and improving clinical outcome, in comparison with intra-arterial heparin administration. However, this was at the expense of an increase in the rate of symptomatic intracranial hemorrhage to 10%. To improve the rate of recanalization, expand the time window, and reduce the risk of symptomatic intracranial hemorrhage, mechanical thrombectomy was introduced, with initial approval of the Merci clot retriever, a corkscrew-like device, and then more recently with approval of the Penumbra thromboaspiration system. Both devices are associated with a high rate of recanalization (total, partial, and complete). However, time to recanalization was on average 45 minutes, with a low rate of complete clot resolution, given that the majority of patients achieved only partial recanalization. More recently, retrievable stents have shown promise in reducing the time to recanalization, and they achieve a higher rate of complete clot resolution with improved feasibility. The retrievable stent can be opened within the clot to engage it within the stent struts, and subsequently it is retrieved by pulling it under flow arrest. The retrievable stents provide a new tool in the armamentarium of devices that can be used to achieve safe and timely clot removal. This review provides the historical evolution of endovascular therapy to use of stentreivers.

Initial Experience Using the 5MAX™ ACE Reperfusion Catheter in Intra-arterial Therapy for Acute Ischemic Stroke

Objectives The 5MAX ACE is a new large bore aspiration catheter available for vessel recanalization for treatment of acute ischemic stroke (AIS). We report our initial experience with its use. Methods A retrospective analysis of patients undergoing intra-arterial therapy for AIS using the 5MAX ACE reperfusion catheter at our institution was performed. Patient demographics, clinical characteristics and procedural data were obtained from chart review. Successful recanlization was defined as achievement of Thrombolysis in Cerebral Infarction score (TICI) 2b-3 and time to recanalization was defined as time from groin puncture to achievement of at least TICI 2b recanalization. Results The 5MAX ACE was used in 15 patients from July-October 2013. Direct aspiration was used as the primary technique in 10/15 (67%) patients. Out of these, aspiration alone was sufficient for recanalization in 3 (20%) patients. In the remaining 7 (47%) patients, additional devices were used. In 5/15 (33%) patients, combined aspiration/stentriever thrombectomy using Solitaire™ (3/5 patients) and Penumbra 3D Separator™ (2/5 patients) were used as the primary technique. Successful recanlization (TICI 2b-3) was achieved in 11/15 (73%) patients. Average time from groin puncture to successful recanalization was 46 +/- 30 minutes (range 14-98 minutes). There were no procedural complications. Conclusion The 5MAX ACE is a useful recanalization tool, either by direct aspiration or combined stentriever/aspiration. It may be most advantageous with large clots in the internal carotid artery. The potential for effective and faster recanalization using this device alone or in combination may be a good topic for future study.

Long-term Follow-up of In-stent Stenosis After Pipeline Flow Diversion Treatment of Intracranial Aneurysms

BACKGROUND There is scant information on in-stent stenosis after flow diversion treatment of intracranial aneurysms with the Pipeline Embolization Device (PED). OBJECTIVE To assess the incidence, severity, nature, and clinical consequences of in-stent stenosis on angiographic follow-up after treatment with the PED. METHODS A retrospective study of patients who underwent aneurysm treatment with the PED was conducted. In-stent stenosis was assessed on subsequent follow-up angiography. Intimal hyperplasia was defined as a uniform growth process beyond the limits of the metallic mesh at <25%. In-stent stenosis represented an area of parent vessel narrowing, most often focal, graded as mild (25%-50%), moderate (50%-75%), or severe (>75%). RESULTS Between June 2011 and April 2015, 80 patients were treated with the PED. Angiographic follow-up was available for 51 patients (representing 76% of available or 64% of all patients). Mean follow-up was 12.5 months. In-stent stenosis was detected in 5 patients (9.8%) at a median of 6 months. Stenosis was mild in 4 of 5 (80%) and moderate in 1 of 5 (20%) patients. There were no cases of severe stenosis. No stenosis caused flow limitation, clinical symptoms, or required re-treatment. Additional follow-up angiography was available in 2 of 5 stenosis patients showing marked improvement. Sixteen patients (31%) had intimal hyperplasia, and 28 patients (55%) had no stenosis. Asymptomatic stent occlusion occurred in 2 patients (4%) related to medication noncompliance. CONCLUSION Treatment with the PED was associated with a 9.8% rate of in-stent stenosis, detected on first angiographic follow-up, at a median of 6 months. None were symptomatic or required re-treatment, and they showed significant improvement on follow-up. ABBREVIATION FD, flow diverter.

Mycotic aneurysm detection rates with cerebral angiography in patients with infective endocarditis

Background Cerebral angiography remains the gold standard for the detection of mycotic aneurysms, and it has been estimated that ruptured mycotic aneurysms result in 5% of the neurological complications of patients with infective endocarditis (IE). Objective To determine the diagnostic yield of cerebral angiography in the above patient population and to assess patient factors that might suggest greater or lesser utility. Methods We retrospectively reviewed 168 patients who underwent cerebral angiography with a diagnosis of IE or infected left ventricular assist device at the Cleveland Clinic between January 2003 and March 2010 in accordance with institutional review board guidelines. Chart and imaging review was performed. Results 15/168 patients (8.9%) had mycotic aneurysms; 93.3% (14/15) of the patients with mycotic aneurysms presented with CNS hemorrhage and 66.7% (10/15) had acute ischemic findings. Of the 15 patients with mycotic aneurysms on angiography, seven underwent CT angiography and six underwent MR angiography, which showed mycotic aneurysms in three (42.9%) and two cases (one of which was questionable; 33.3%), respectively. Conclusions Patients with IE or similar sources of central bacterial emboli are prone to neurovascular complications. Approximately 9% of patients with IE at our institution who undergo cerebral angiography have mycotic aneurysms. Presentation with hemorrhage appears to be more predictive of aneurysm, as approximately 22% of patients with IE and hemorrhage were found to have an aneurysm compared with only 1% when hemorrhage was absent. Thus, patients with IE presenting with intracranial hemorrhage should undergo vascular imaging, preferably with cerebral angiography.

Predictors of Infarct Growth after Endovascular Therapy for Acute Ischemic Stroke

BACKGROUND Intra-arterial (IA) thrombectomy for acute ischemic stroke has an excellent recanalization rate but variable outcomes. The core infarct also grows at a variable rate despite recanalization. We aim to study the factors that are associated with infarct growth after IA therapy. METHODS We reviewed the hyperacute ischemic stroke imaging database at Cleveland Clinic for those undergoing endovascular thrombectomy of anterior circulation from 2009 to 2012. Patients with both pretreatment and follow-up magnetic resonance imaging were included. Seventy-six patients were stratified into quartiles by infarct volume growth from initial to follow-up diffusion-weighted imaging (DWI) measure by a region of interest demarcation. RESULTS The median infarct growth of each quartile was .6 cm(3) (no-growth group), 13.8, 37, and 160.2 cm(3) (large-growth group). Pretreatment stroke severity was comparable among groups. Compared with the no-growth group, the large-growth group had larger initial infarct defined by computed tomography (CT) Alberta Stroke Program Early CT score (median 10 versus 8, P = .032) and DWI volume (mean 13.8 versus 29.2 cm(3), P = .034), lack of full collateral vessels on CT angiography (36.8% versus 0%, P = .003), and a lower recanalization rate (thrombolysis in cerebral infarction ≥2b, P = .044). The increase in infarct growth is associated with decrease in favorable outcomes defined by a modified Rankin Scale score of 0-2 at 30 days: 57.9%, 42.1%, 21.1%, and 5.3%, respectively (P < .001). DWI reversal was observed in 11 of 76 patients, translating to 82% favorable outcome. CONCLUSIONS Infarct evolution after endovascular thrombectomy is associated with an outcome. DWI reversal or no growth translated to a favorable outcome. Small initial ischemic core, good collateral support, and better recanalization grades predict the smaller infarct growth and favorable outcome after endovascular thrombectomy.

Emergent mechanical thrombectomy for acute stroke using the Mindframe Capture LP system: initial single-center experience.

Background Mechanical thrombectomy using stentrievers is the standard of care for emergent large vessel occlusion stroke. Data on the use of stentrievers in smaller caliber vessels are sparse. Objective To present our initial experience with the Mindframe Capture LP device, which was designed for mechanical thrombectomy in small cerebral arteries. Methods A retrospective chart review was conducted of patients who underwent Mindframe device assisted emergent thrombectomy. Clinical, imaging, procedural and early follow-up data were obtained. Results Nine patients met inclusion criteria (5 men, median age 62 years). Median National Institute of Health Stroke Scale (NIHSS) score was 18 (IQR 9–22), and 6 patients received intravenous tissue plasminogen activator. Six patients had M2 segment occlusions, and 2 patients had distal M1 segment occlusions of the middle cerebral artery. One had distal basilar artery occlusion. Median vessel diameter at the thrombus was 1.7 mm (IQR 1.5–2.5). In all 9 patients the Mindframe device was used together with manual aspiration, with median groin puncture to recanalization time of 35 min (IQR 27–54), and median procedural time of 67 min (IQR 51–91). Final Thrombolysis in Cerebral Infarction score was 3 and 2b in 4 patients each (89% total), and 2a in 1 patient. No patient had any postprocedural complications or symptomatic intracerebral hemorrhage. Median postprocedure and discharge NIHSS were 4 and 1, respectively. Conclusions Our data suggest that the Mindframe device is safe and effective for rapid treatment of acute strokes involving small caliber intracranial vessels. Further study in a larger cohort is warranted.

Flow diverter treatment of intracranial vertebral artery dissecting pseudoaneurysms

Introduction Intracranial vertebral dissecting pseudoaneurysms are a rare, but increasingly recognized, cause of subarachnoid hemorrhage and ischemic stroke. The risks of aneurysm re-rupture and associated morbidity are high. The use of flow diverter stents for the treatment of these aneurysms has not been well studied. Objective To report our data and provide a summarized review of literature using flow diverter stents for the treatment of intracranial vertebral artery dissecting pseudoaneurysms. Methods We performed a retrospective analysis of flow diverter stents used for the treatment of intracranial vertebral artery dissecting pseudoaneurysms. Clinical, imaging, procedural, and follow-up data were collected. Results We identified eight vertebral dissecting pseudoaneurysms in seven patients (5 (71.4%) female; median age 47 years (IQR 46–52)) who had undergone treatment with flow diverter stents. In 4/7 patients (57.1%) the aneurysm had ruptured; however, only one was treated in the acute phase. Median size of the largest diameter of the aneurysm was 6.3 mm (IQR 4.2–8.8), and 7/8 aneurysms (87.5%) were treated with a single flow diverter device. Three aneurysms were concurrently coiled. Angiographic complete occlusion was seen in 6/8 (75%) aneurysms at a median follow-up of 14 months (IQR 7.7–20.2). Two patients had periprocedural strokes with transient neurologic deficits. All patients had a good clinical outcome (modified Rankin Scale score ≤2). There were no re-treatments or aneurysm ruptures during the follow-up period. Conclusions Our experience suggests that flow diverter stent treatment of intracranial vertebral artery dissecting pseudoaneurysms is safe, and associated with good occlusion rates and favorable clinical outcomes.