Kenneth V. Snyder

First Food and Drug Administration-Approved Prospective Trial of Primary Intracranial Stenting for Acute Stroke SARIS (Stent-Assisted Recanalization in Acute Ischemic Stroke)

Background and Purpose— Acute revascularization is associated with improved outcomes in ischemic stroke patients. However, it is unclear which method of intraarterial intervention, if any, is ideal. Numerous case series and cardiac literature parallels suggest that acute stenting may yield high revascularization levels with low associated morbidity. We therefore conducted a Food and Drug Administration-approved prospective pilot trial to evaluate the safety of intracranial stenting for acute ischemic stroke. Methods— Eligibility criteria included presentation ≤8 hours after stroke onset, age 18 years or older, National Institutes of Health Stroke Scale score ≥8, angiographic demonstration of focal intracerebral artery occlusion ≤14 mm, and either contraindication to intravenous tissue plasminogen activator or failure to improve 1 hour after intravenous tissue plasminogen activator administration. Exclusion criteria included known hemorrhagic diathesis or coagulopathy, platelet count <100 000, intracranial hemorrhage, blood glucose level of <51 mg/100 mL, or CT perfusion imaging demonstrating more than one-third at-risk territory with nonsalvageable brain (low cerebral blood volume). Data are presented as mean±SD. Results— Twenty patients were enrolled (mean age, 63±18 years;14 women). Mean presenting National Institutes of Health Stroke Scale was 14±3.8 (median 13). Presenting thrombolysis in myocardial infarction score was 0 (85% of patients) or 1 (15%). Recanalization to thrombolysis in myocardial infarction score of 3 (60% of patients) or 2 (40% of patients; P<0.0001) was achieved. One (5%) symptomatic and 2 (10%) asymptomatic intracranial hemorrhages occurred. At 1-month follow-up, a modified Rankin scale score of ≤3 was achieved in 12 of 20(60%) patients and a modified Rankin scale score of ≤1 was achieved in 9 of 20 (45%) patients. Conclusion— This Food and Drug Administration-approved prospective study suggests primary intracranial stenting for acute stroke may be a valuable addition to the stroke treatment armamentarium.

Early postmarket results after treatment of intracranial aneurysms with the pipeline embolization device: A US multicenter experience

BACKGROUND The pipeline embolization device (PED) is the latest technology available for intracranial aneurysm treatment. OBJECTIVE To report early postmarket results with the PED. METHODS This study was a prospective registry of patients treated with PEDs at 7 American neurosurgical centers subsequent to Food and Drug Administration approval of this device. Data collected included clinical presentation, aneurysm characteristics, treatment details, and periprocedural events. Follow-up data included degree of aneurysm occlusion and delayed (> 30 days after the procedure) complications. RESULTS Sixty-two PED procedures were performed to treat 58 aneurysms in 56 patients. Thirty-seven of the aneurysms (64%) treated were located from the cavernous to the superior hypophyseal artery segment of the internal carotid artery; 22% were distal to that segment, and 14% were in the vertebrobasilar system. A total of 123 PEDs were deployed with an average of 2 implanted per aneurysm treated. Six devices were incompletely deployed; in these cases, rescue balloon angioplasty was required. Six periprocedural (during the procedure/within 30 days after the procedure) thromboembolic events occurred, of which 5 were in patients with vertebrobasilar aneurysms. There were 4 fatal postprocedural hemorrhages (from 2 giant basilar trunk and 2 large ophthalmic artery aneurysms). The major complication rate (permanent disability/death resulting from perioperative/delayed complication) was 8.5%. Among 19 patients with 3-month follow-up angiography, 68% (13 patients) had complete aneurysm occlusion. Two patients presented with delayed flow-limiting in-stent stenosis that was successfully treated with angioplasty. CONCLUSION Unlike conventional coil embolization, aneurysm occlusion with PED is not immediate. Early complications include both thromboembolic and hemorrhagic events and appear to be significantly more frequent in association with treatment of vertebrobasilar aneurysms.

Safety and Effectiveness of Endovascular Therapy After 8 Hours of Acute Ischemic Stroke Onset and Wake-Up Strokes

Background and Purpose— This is a retrospective review of patients who underwent endovascular recanalization ≥8 hours after acute ischemic stroke symptom onset, including wake-up strokes, between June 2005 and June 2008. Methods— Thirty patients with a premorbid modified Rankin score ≤1 and NIHSS between 5 and 22 were included. All had admission CT, CTA, and CT perfusion scans to evaluate for salvageable brain tissue. Recanalization effectiveness was assessed by angiograms obtained within 30 hours after intervention. Patient, treatment characteristics, and immediate and 3-month outcomes were analyzed. Results— Mean NIHSS at presentation was 13 (median=12). Mean interval between time last-seen well and angiogram was 12.75 hours (median=10). Twenty-six patients (86.7%) presented with complete-to-near-complete vessel occlusion (thrombolysis in myocardial infarction [TIMI] 0/1); 4 had partial vessel occlusion (TIMI 2). Interventions included intra-arterial pharmacological thrombolysis (n=10), mechanical thrombectomy(n=21; Merci, 16; intracranial stent, 9; extracranial stent, 3), angioplasty (n=14; intracranial, 11; extracranial, 3). Nine patients received GPIIb/IIIa inhibitors (eptifibatide); all received heparin. Partial-to-complete recanalization (TIMI 2/3) was achieved in 20 patients (66.7%). Procedure-related complications included vascular perforations (n=3) and femoral access site complication (n=1). One patient had an embolic anterior cerebral artery infarct during intervention; another had progression of brain stem infarct. Symptomatic intracerebral hemorrhage occurred in 3 patients (10%), with 2 being primarily subarachnoid in location. Total in-hospital mortality including procedural mortality, disease progression, or other comorbidities was 23.3% (n=7). Mean discharge NIHSS was 9.5, representing an overall NIHSS 3.5-point improvement. Overall, mean modified Rankin score at death or last follow-up (mean=10.6 months) was 4.2. At 3 months, total mortality was 33.3% (n=10), 20% had modified Rankin score ≤2, and 33% had modified Rankin score ≤3. Among survivors, mean modified Rankin score at 3-month follow-up was 3. Conclusion— Our data show that delayed endovascular revascularization of carefully selected patients is safe, effective, and improves clinical outcome.

Delayed thrombosis or stenosis following enterprise-assisted stent-coiling: Is it safe? Midterm results of the interstate collaboration of enterprise stent coiling

BACKGROUND:Stent-assisted coiling of intracranial aneurysms with self-expanding stents has widened the applicability of neuroendovascular therapies to those aneurysms previously considered “uncoilable” because of poor morphology. The Enterprise Vascular Reconstruction Device and Delivery System (Cordis) has demonstrated promising initial short-term results. However, the rates of delayed in-stent stenosis or thrombosis are not known. OBJECTIVE:To report midterm results of the Enterprise stent system. METHODS:A 10-center registry was created to provide a large volume of data on the safety and efficacy of the Enterprise stent system. Pooled data were compiled for consecutive patients undergoing Enterprise stent-assisted coiling at each institution. Available follow-up data were evaluated for the incidence of in-stent stenosis, thrombosis, and aneurysm occlusion. RESULTS:In total, 213 patients (176 females) with 219 aneurysms were treated with the Enterprise stent. One hundred ten patients had undergone delayed angiography (≥30 days from stent placement, mean follow-up 174.6 days). Forty percent of patients demonstrated total occlusion with 88% having ≥90% aneurysm occlusion. Six percent of patients had delayed (>30 days) angiographic findings, of which 3% demonstrated significant (≥50%) in-stent stenosis or occlusion. Seven delayed thrombotic events occurred (3%), along with 2 additional immediate periprocedural events. All 7 delayed events were concomitant to cessation of double-antiplatelet therapy. CONCLUSION:Midterm occlusion rates are excellent, and stenosis and thrombosis rates are comparable to other available neurovascular stents. Interruption of antiplatelet therapy appears to be a factor in those developing delayed stenosis or thrombosis.

CFD: Computational Fluid Dynamics or Confounding Factor Dissemination? The Role of Hemodynamics in Intracranial Aneurysm Rupture Risk Assessment

SUMMARY: Image-based computational fluid dynamics holds a prominent position in the evaluation of intracranial aneurysms, especially as a promising tool to stratify rupture risk. Current computational fluid dynamics findings correlating both high and low wall shear stress with intracranial aneurysm growth and rupture puzzle researchers and clinicians alike. These conflicting findings may stem from inconsistent parameter definitions, small datasets, and intrinsic complexities in intracranial aneurysm growth and rupture. In Part 1 of this 2-part review, we proposed a unifying hypothesis: both high and low wall shear stress drive intracranial aneurysm growth and rupture through mural cell–mediated and inflammatory cell–mediated destructive remodeling pathways, respectively. In the present report, Part 2, we delineate different wall shear stress parameter definitions and survey recent computational fluid dynamics studies, in light of this mechanistic heterogeneity. In the future, we expect that larger datasets, better analyses, and increased understanding of hemodynamic-biologic mechanisms will lead to more accurate predictive models for intracranial aneurysm risk assessment from computational fluid dynamics.

Use of a vascular reconstruction device to salvage acute ischemic occlusions refractory to traditional endovascular recanalization methods.

OBJECT Acute revascularization has been associated with improved stroke outcomes. The Prolyse in Acute Cerebral Thromboembolism (PROACT II) trial achieved recanalization rates of 66%. The Multi Mechanical Embolus Removal in Cerebral Ischemia (Multi MERCI) trial achieved recanalization in 70% of patients. However, these interventional tools are not always successful. The Enterprise vascular reconstruction device was recently introduced for treatment of cerebral aneurysms previously untreatable with endovascular techniques. The authors evaluated a multicenter experience using this stent as a salvage revascularization tool for acute stroke treatment. METHODS Four medical centers participated in a retrospective review of endovascularly treated patients with acute stroke for cases treated with the Enterprise stent after routine interventions had been unsuccessful. Data collected included preprocedure information, intraprocedure findings, and outcomes. RESULTS Twenty patients with acute stroke (mean age 61.6 +/- 22 years) were treated with the Enterprise stent. Ten patients received intravenous recombinant tissue plasminogen activator before catheter intervention, without improvement. Intraarterial interventions attempted unsuccessfully before Enterprise deployment included the Merci retriever (12 patients), angioplasty (7 patients), glycoprotein IIb-IIIa inhibitor administration (12 patients), intraarterial nitroglycerin (1 patient), Wingspan stent deployment (3 patients), and Xpert stent deployment (1 patient). The mean preintervention National Institutes of Health Stroke Scale (NIHSS) score was 17 +/- 6 (median 17). All patients presented with a Thrombolysis in Myocardial Infarction (TIMI) score of 0 or 1. Revascularization was achieved in all patients (75% with a TIMI score of 3, 25% with a TIMI score of 2). Improvement (> or = 4 points on the NIHSS) was documented in 75% of patients. Mean NIHSS improvement from intervention to discharge was 8 +/- 7 points (median 9 points). CONCLUSIONS These preliminary data suggest a potential benefit to the use of the Enterprise stent when routine intervention methods fail.

Utilization of Pipeline embolization device for treatment of ruptured intracranial aneurysms: US multicenter experience

Objective Utilization of the Pipeline embolization device (PED) in complex ruptured aneurysms has not been well studied. We evaluated the safety and effectiveness data from five participating US centers. Methods Records of patients with ruptured cerebral aneurysms who underwent PED treatment between 2011 and 2013 were retrospectively reviewed. Results 26 patients with ruptured aneurysms underwent PED treatment (mean age 51.4±13.2 years;16 women). At presentation, 8 patients (30.8%) had a Hunt–Hess grade of IV or above; 11 required extraventricular drain placement. Aneurysm morphologies were: 8 dissecting, 8 blister-like, 6 fusiform, and 4 saccular. There were 22 anterior circulation and 4 posterior circulation aneurysms. PED deployment was successful in all patients, with adjunctive coiling utilized in 12. Periprocedural complications occurred in 5 (19.2%), including 3 inhospital deaths. 23 patients (88.5%) had postoperative angiography at a mean of 5.9 months: 18 aneurysms (78.3%) were completely occluded, 3 (13.0%) had residual neck filling, and 2 (8.7%) had residual dome filling. All blister-type aneurysms were completely occluded at follow-up. Clinical follow-up was available for an average of 10.1 months (range 2–21 months), with one asymptomatic in-stent stenosis and one asymptomatic thromboembolic stroke noted. Good outcome (modified Rankin Scale (mRS) score of 0–2) was achieved in 20 patients (76.9%), fair (mRS 3–4) in 3 (11.5%), and 3 died (11.5%). Conclusions The PED can be utilized for ruptured aneurysms and is a good option for blister-type aneurysms. However, due to periprocedural complications, it should be reserved for lesions that are difficult to treat by conventional clipping or coiling.

Intravenous Thrombolysis and Endovascular Therapy for Acute Ischemic Stroke With Internal Carotid Artery Occlusion: A Systematic Review of Clinical Outcomes

Background and Purpose— Strokes secondary to acute internal carotid artery (ICA) occlusion are associated with extremely poor prognosis. The best treatment approach to acute stroke in this setting is unknown. We sought to determine clinical outcomes in patients with acute ischemic stroke attributable to ICA occlusion treated with intravenous (IV) systemic thrombolysis or intra-arterial endovascular therapy. Methods— Using the PubMed database, we searched for studies that included patients with acute ischemic stroke attributable to ICA occlusion who received treatment with IV thrombolysis or intra-arterial endovascular interventions. Studies providing data on functional outcomes beyond 30 days and mortality and symptomatic intracerebral hemorrhage (sICH) rates were included in our analysis. We compared the proportions of patients with favorable functional outcomes, sICH, and mortality rates in the 2 treatment groups by calculating &khgr;2 and confidence intervals for odds ratios. Results— We identified 28 studies with 385 patients in the IV thrombolysis group and 584 in the endovascular group. Rates of favorable outcomes and sICH were significantly higher in the endovascular group than the IV thrombolysis-only group (33.6% vs 24.9%, P=0.004 and 11.1% vs 4.9%, P=0.001, respectively). No significant difference in mortality rate was found between the groups (27.3% in the IV thrombolysis group vs 32.0% in the endovascular group; P=0.12). Conclusions— According to our systematic review, endovascular treatment of acute ICA occlusion results in improved clinical outcomes. A higher rate of sICH after endovascular treatment does not result in increased overall mortality rate.

Solitaire flow restoration thrombectomy for acute ischemic stroke: Retrospective multicenter analysis of early postmarket experience after FDA approval

BACKGROUND The promising results of the Solitaire Flow Restoration (FR) With the Intention for Thrombectomy (SWIFT) trial recently led to Food and Drug Administration (FDA) approval of the Solitaire FR stent retriever device for recanalization of cerebral vessels in patients with acute ischemic stroke. OBJECTIVE To report the early postmarket experience with this device since its FDA approval in the United States, which has not been previously described. METHODS We conducted a retrospective analysis of consecutive acute ischemic strokes cases treated between March 2012 and July 2012 at 10 United States centers where the Solitaire FR was used as a single device or in conjunction with other intraarterial endovascular approaches. RESULTS A total of 101 patients were identified (mean age, 64.7 years; mean admission National Institutes of Health Stroke Scale [NIHSS] score, 17.6). Intravenous thrombolysis was administered in 39% of cases; other endovascular techniques were utilized in conjunction with the Solitaire FR in 52%. Successful recanalization (Thrombolysis in Myocardial Infarction 2/3) was achieved in 88%. The rate of symptomatic intracranial hemorrhage within the first 24 hours was 15%. In-hospital mortality was 26%. At 30 days, 38% of patients had favorable functional outcome (modified Rankin scale score ≤2). Severity of NIHSS score on admission was a strong predictor of poor outcome. CONCLUSION Our study shows that a variety of other endovascular approaches are used in conjunction with Solitaire FR in actual practice in the United States. Early postmarket results suggest that Solitaire FR is an effective tool for endovascular treatment of acute ischemic stroke.

Thrombus density predicts successful recanalization with Solitaire stent retriever thrombectomy in acute ischemic stroke

Background Thrombus characteristics, including Hounsfield unit (HU) value to measure density and thrombus volume and length, can predict successful recanalization following IV thrombolysis with recombinant tissue plasminogen activator. Conflicting and limited data exist regarding the value of assessing thrombus properties in acute stroke cases treated with endovascular IA approaches. Methods We retrospectively reviewed cases of anterior circulation acute ischemic stroke in which a Solitaire stent retriever (ev3-Covidien) was the primary treatment device. We measured the following thrombus characteristics: absolute and corrected HU values; thrombus length and volume; clot burden score; and vessel bifurcation involvement. Fishers exact test and the t test were used to study the association between these clot characteristics and successful recanalization (Thrombolysis in Cerebral Infarction (TICI) score 2b–3). Results We identified 41 patients with anterior circulation stroke treated with the Solitaire stent retriever as the primary treatment device. Successful recanalization (TICI score 2b–3) was achieved in 59% of cases. Higher absolute and corrected HU values were strongly predictive of successful recanalization (49.9±7.6 vs 43.8±6.6, p=0.01 for absolute HU values and 1.2±0.2 vs 1.0±0.1, p=0.03 for HU ratio in TICI 2b–3 and TICI 0–2a groups, respectively). There was no significant difference between recanalization and non-recanalization groups in the other thrombus characteristics studied. Conclusions In acute stroke treated with Solitaire stent retriever thrombectomy, higher thrombus HU values are predictive of successful recanalization. Such information can be used in decision making when estimating recanalization success rate with different endovascular treatment approaches.