Endovascular therapy in the distal neurovascular territory: results of a large prospective registry.

BACKGROUND: There is a paucity of data regarding mechanical thrombectomy (MT) in distal arterial occlusions (DAO). We aim to evaluate the safety and efficacy of MT in patients with DAO and compare their outcomes with proximal arterial occlusion (PAO) strokes. METHODS: The Trevo Registry was a prospective open-label MT registry including 2008 patients from 76 sites across 12 countries. Patients were categorized into: PAO: intracranial ICA, and MCA-M1; and DAO: MCA-M2, MCA-M3, ACA, and PCA. Baseline and outcome variables were compared across the PAO vs DAO patients with pre-morbid mRS 0-2. RESULTS: Among 407 DAOs including 350 (86.0%) M2, 25 (6.1%) M3, 10 (2.5%) ACA, and 22 (5.4%) PCA occlusions, there were 376 DAO with pre-morbid mRS 0-2 which were compared with 1268 PAO patients. The median baseline NIHSS score was lower in DAO (13 [8-18] vs 16 [12-20], P<0.001). There were no differences in terms of age, sex, IV-tPA use, co-morbidities, or time to treatment across DAO vs PAO. The rates of post-procedure reperfusion, symptomatic intracranial hemorrhage (sICH), and 90-mortality were comparable between both groups. DAO showed significantly higher rates of 90-day mRS 0-2 (68.3% vs 56.5%, P<0.001). After adjustment for potential confounders, the level of arterial occlusion was not associated with the chances of excellent outcome (DAO for 90-day mRS 0-1: OR; 1.18, 95% CI [0.90 to 1.54], P=0.225), successful reperfusion or SICH. However, DAO patients were more likely to be functionally independent (mRS 0-2: OR; 1.45, 95% CI [1,09 to 1.92], P=0.01) or dead (OR; 1.54, 95% CI [1.06 to 2.27], P=0.02) at 90 days. CONCLUSION: Endovascular therapy in DAO appears to result in a comparable safety and technical success profile as in PAO. The potential benefits of DAO thrombectomy should be investigated in future randomized trials.

Mechanical Thrombectomy for Delayed Thrombosis of Pipeline Embolization Device.

BACKGROUND: In-stent thrombosis is a potentially dangerous complication of flow diversion for cerebral aneurysms. The optimal management strategy for such thrombosis is not known. Here we present a case of acute ischemic stroke caused by occlusion of a Pipeline Embolization Device (PED) construct placed 18 months earlier for treatment of a fusiform middle cerebral artery aneurysm. This was successfully treated with mechanical thrombectomy with good neurologic outcome. CASE DESCRIPTION: A 40-year-old woman presented with acute onset of left-sided weakness and occlusion of the right middle cerebral artery harboring a PED construct. Intraarterial glycoprotein IIb/IIIa inhibitor was administered without success. Mechanical thrombectomy was then performed using a stent retriever and aspiration, and the patient was loaded with dual antiplatelet therapy. The patient showed initial neurologic improvement but several hours later demonstrated recurrent symptoms due to reocclusion of the PED construct. This was again treated with mechanical thrombectomy followed by an intravenous P2Y12 inhibitor infusion. She ultimately made an excellent neurologic recovery with persistent patency of the PED construct. CONCLUSIONS: Mechanical thrombectomy with a stent retriever and aspiration is a therapeutic option for treatment of delayed thrombosis of a flow-diverting stent.

Impact of Balloon Guide Catheter Use on Clinical and Angiographic Outcomes in the STRATIS Stroke Thrombectomy Registry.

Background and Purpose- Mechanical thrombectomy has been shown to improve clinical outcomes in patients with acute ischemic stroke. However, the impact of balloon guide catheter (BGC) use is not well established. Methods- STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter study of patients with large vessel occlusion treated with the Solitaire stent retriever as first-line therapy. In this study, an independent core laboratory, blinded to the clinical outcomes, reviewed all procedures and angiographic data to classify procedural technique, target clot location, recanalization after each pass, and determine the number of stent retriever passes. The primary clinical end point was functional independence (modified Rankin Scale, 0-2) at 3 months as determined on-site, and the angiographic end point was first-pass effect (FPE) success rate from a single device attempt (modified Thrombolysis in Cerebral Infarction, ≥2c) as determined by a core laboratory. Achieving modified FPE (modified Thrombolysis in Cerebral Infarction, ≥2b) was also assessed. Comparisons of clinical outcomes were made between groups and adjusted for baseline and procedural characteristics. All participating centers received institutional review board approval from their respective institutions. Results- Adjunctive technique groups included BGC (n=445), distal access catheter (n=238), and conventional guide catheter (n=62). The BGC group had a higher rate of FPE following first pass (212/443 [48%]) versus conventional guide catheter (16/62 [26%]; P=0.001) and distal access catheter (83/235 [35%]; P=0.002). Similarly, the BGC group had a higher rate of modified FPE (294/443 [66%]) versus conventional guide catheter (26/62 [42%]; P<0.001) and distal access catheter (129/234 [55%]; P=0.003). The BGC group achieved the highest rate of functional independence (253/415 [61%]) versus conventional guide catheter (23/55 [42%]; P=0.007) and distal access catheter (113/218 [52%]; P=0.027). Final revascularization and mortality rates did not differ across the groups. Conclusions- BGC use was an independent predictor of FPE, modified FPE, and functional independence, suggesting that its routine use may improve the rates of early revascularization success and good clinical outcomes. Clinical Trial Registration- URL: https://www.clinicaltrials.gov . Unique identifier: NCT02239640.

Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke).

BACKGROUND: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation. METHODS: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0-2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass. RESULTS: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients (P<0.001). Clinical outcomes were better in the direct group, with 60.0% (299/498) achieving functional independence compared with 52.2% (213/408) in the transfer group (odds ratio, 1.38; 95% confidence interval, 1.06-1.79; P=0.02). Likewise, excellent outcome (modified Rankin Score 0-1) was achieved in 47.4% (236/498) of direct patients versus 38.0% (155/408) of transfer patients (odds ratio, 1.47; 95% confidence interval, 1.13-1.92; P=0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer; P=0.55). Intravenous tissue plasminogen activator did not impact outcomes. Hypothetical bypass modeling for all transferred patients suggested that intravenous tissue plasminogen activator would be delayed by 12 minutes, but MT would be performed 91 minutes sooner if patients were routed directly to endovascular-capable centers. If bypass is limited to a 20-mile radius from onset, then intravenous tissue plasminogen activator would be delayed by 7 minutes and MT performed 94 minutes earlier. CONCLUSIONS: In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes. CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640.

Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke: Primary Results of the STRATIS Registry.

BACKGROUND AND PURPOSE: Mechanical thrombectomy with stent retrievers has become standard of care for treatment of acute ischemic stroke patients because of large vessel occlusion. The STRATIS registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) aimed to assess whether similar process timelines, technical, and functional outcomes could be achieved in a large real world cohort as in the randomized trials. METHODS: STRATIS was designed to prospectively enroll patients treated in the United States with a Solitaire Revascularization Device and Mindframe Capture Low Profile Revascularization Device within 8 hours from symptom onset. The STRATIS cohort was compared with the interventional cohort of a previously published SEER patient-level meta-analysis. RESULTS: A total of 984 patients treated at 55 sites were analyzed. The mean National Institutes of Health Stroke Scale score was 17.3. Intravenous tissue-type plasminogen activator was administered in 64.0%. The median time from onset to arrival in the enrolling hospital, door to puncture, and puncture to reperfusion were 138, 72, and 36 minutes, respectively. The Core lab-adjudicated modified Thrombolysis in Cerebral Infarction ≥2b was achieved in 87.9% of patients. At 90 days, 56.5% achieved a modified Rankin Scale score of 0 to 2, all-cause mortality was 14.4%, and 1.4% suffered a symptomatic intracranial hemorrhage. The median time from emergency medical services scene arrival to puncture was 152 minutes, and each hour delay in this interval was associated with a 5.5% absolute decline in the likelihood of achieving modified Rankin Scale score 0 to 2. CONCLUSIONS: This largest-to-date Solitaire registry documents that the results of the randomized trials can be reproduced in the community. The decrease of clinical benefit over time warrants optimization of the system of care. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02239640.

Internal carotid artery dissection after a roller coaster ride in a 4-year-old: case report and review of the literature.

BACKGROUND: Strokes associated with roller-coaster rides are unusual. PATIENT: A previously healthy 4-year-old boy developed acute onset of left-sided weakness when flying home from a trip to an amusement park. He had frequented two roller coaster rides the day prior. Upon evaluation, he was found to have an acute right middle cerebral artery territory infarction. RESULTS: Cerebral angiography showed dissection of the right cervical internal carotid artery and right middle cerebral artery occlusion involving the M1 segment. He was treated with aspirin. Evaluation for underlying connective tissue diseases was unremarkable. CONCLUSION: We speculate that repetitive forces of acceleration and deceleration may have led to a cervical internal carotid artery intimal tear, followed by thromboembolism. It remains uncertain what the threshold of susceptibility to repetitive rotational changes and tolerability to G forces in an otherwise healthy child truly is.

The SPEED study: initial clinical evaluation of the Penumbra novel 054 Reperfusion Catheter.

BACKGROUND AND PURPOSE: Revascularization of acute ischemic stroke from a large vessel occlusion continues to be a challenge with current thrombectomy devices. The purpose of the SPEED study was to report the safety and effectiveness of the Penumbra 054 Reperfusion Catheter System in revascularizing large vessel occlusions. METHODS: In this retrospective multicenter study, data were collected from patients with angiographic evidence of large vessel occlusion treated with the Penumbra 054 device as the intended primary therapy. Clinical outcome data were collected with 90-day follow-up and the results were compared with those from the Penumbra Pivotal trial. RESULTS: Eighty-seven target vessels in 86 consecutive patients treated with the Penumbra 054 device were included. The Thrombolysis In Myocardial Infarction (TIMI) 2 or 3 revascularization rate was 91% compared with a reported 82% in the Penumbra Pivotal trial. This was accomplished in a median time of 20 min compared with 45 min in the Penumbra Pivotal trial (p<0.0001). Eighteen (21%) patients experienced an intracranial hemorrhage of which 12 (14%) were symptomatic. Good neurologic outcome (modified Rankin scores ≤ 2) at 90-day follow-up was achieved in 34.9% of patients compared with 25% reported in the Penumbra Pivotal trial. All-cause mortality was 25.6%. CONCLUSIONS: These results suggest that the Penumbra 054 is a fast, safe and effective revascularization tool for patients experiencing ischemic stroke secondary to large vessel occlusive disease. Improvements in speed and effectiveness of revascularization probably contributed to improved outcomes.

Mechanical thrombectomy for acute ischemic stroke: final results of the Multi MERCI trial.

BACKGROUND AND PURPOSE: Endovascular mechanical thrombectomy may be used during acute ischemic stroke due to large vessel intracranial occlusion. First-generation MERCI devices achieved recanalization rates of 48% and, when coupled with intraarterial thrombolytic drugs, recanalization rates of 60% have been reported. Enhancements in embolectomy device design may improve recanalization rates. METHODS: Multi MERCI was an international, multicenter, prospective, single-arm trial of thrombectomy in patients with large vessel stroke treated within 8 hours of symptom onset. Patients with persistent large vessel occlusion after IV tissue plasminogen activator treatment were included. Once the newer generation (L5 Retriever) device became available, investigators were instructed to use the L5 Retriever to open vessels and could subsequently use older generation devices and/or intraarterial tissue plasminogen activator. Primary outcome was recanalization of the target vessel. RESULTS: One hundred sixty-four patients received thrombectomy and 131 were initially treated with the L5 Retriever. Mean age+/-SD was 68+/-16 years, and baseline median (interquartile range) National Institutes of Health Stroke Scale score was 19 (15 to 23). Treatment with the L5 Retriever resulted in successful recanalization in 75 of 131 (57.3%) treatable vessels and in 91 of 131 (69.5%) after adjunctive therapy (intraarterial tissue plasminogen activator, mechanical). Overall, favorable clinical outcomes (modified Rankin Scale 0 to 2) occurred in 36% and mortality was 34%; both outcomes were significantly related to vascular recanalization. Symptomatic intracerebral hemorrhage occurred in 16 patients (9.8%); 4 (2.4%) of these were parenchymal hematoma type II. Clinically significant procedural complications occurred in 9 (5.5%) patients. CONCLUSIONS: Higher rates of recanalization were associated with a newer generation thrombectomy device compared with first-generation devices, but these differences did not achieve statistical significance. Mortality trended lower and the proportion of good clinical outcomes trended higher, consistent with better recanalization.

Safety and efficacy of mechanical embolectomy in acute ischemic stroke: results of the MERCI trial.

BACKGROUND AND PURPOSE: The only Food and Drug Administration (FDA)-approved treatment for acute ischemic stroke is tissue plasminogen activator (tPA) given intravenously within 3 hours of symptom onset. An alternative strategy for opening intracranial vessels during stroke is mechanical embolectomy, especially for patients ineligible for intravenous tPA. METHODS: We investigated the safety and efficacy of a novel embolectomy device (Merci Retriever) to open occluded intracranial large vessels within 8 hours of the onset of stroke symptoms in a prospective, nonrandomized, multicenter trial. All patients were ineligible for intravenous tPA. Primary outcomes were recanalization and safety, and secondary outcomes were neurological outcome at 90 days in recanalized versus nonrecanalized patients. RESULTS: Recanalization was achieved in 46% (69/151) of patients on intention to treat analysis, and in 48% (68/141) of patients in whom the device was deployed. This rate is significantly higher than that expected using an historical control of 18% (P<0.0001). Clinically significant procedural complications occurred in 10 of 141 (7.1%) patients. Symptomatic intracranial hemorrhages was observed in 11 of 141 (7.8%) patients. Good neurological outcomes (modified Rankin score < or =2) were more frequent at 90 days in patients with successful recanalization compared with patients with unsuccessful recanalization (46% versus 10%; relative risk [RR], 4.4; 95% CI, 2.1 to 9.3; P<0.0001), and mortality was less (32% versus 54%; RR, 0.59; 95% CI, 0.39 to 0.89; P=0.01). CONCLUSIONS: A novel endovascular embolectomy device can significantly restore vascular patency during acute ischemic stroke within 8 hours of stroke symptom onset and provides an alternative intervention for patients who are otherwise ineligible for thrombolytics.

Current topics of interest in interventional radiology.

Interventional Radiology utilizes imaging guidance (primarily fluoroscopy, computed tomography and ultrasound) to perform diagnostic and therapeutic procedures in a minimally invasive manner. This update highlights several current and newer interventional radiology options for treatment of uterine fibroids, interventional oncology procedures for liver tumors and metastatic disease, varicose vein treatment, carotid stenting, cerebral aneurysm coiling, and removable inferior vena cava (IVC) filters.

MERCI 1: a phase 1 study of Mechanical Embolus Removal in Cerebral Ischemia.

BACKGROUND AND PURPOSE: To report the result of the Mechanical Embolus Removal in Cerebral Ischemia (MERCI) 1 study, a phase 1 trial to evaluate the safety and efficacy of mechanical embolectomy in the cerebral vasculature. METHODS: MERCI 1 enrolled 30 patients in 7 US centers. Main inclusion criteria were: National Institutes of Health Stroke Scale score (NIHSS) > or =10; treatment performed within 8 hours from symptoms onset and contra-indication to intravenous thrombolysis; no large hypodensity on computed tomography; and occlusion of a major cerebral artery on the angiogram. Safety was defined by the absence of vascular injury or symptomatic intracranial hemorrhage. Efficacy was assessed by recanalization rate and clinical outcome at 1 month. Significant recovery was defined as 30-day modified Rankin of 0 to 2 in patients with baseline NIHSS 10 to 20 and 30-day modified Rankin of 0 to 3 in patients with baseline NIHSS >20. The procedures were performed with the Merci Retrieval System, a system specially designed for intracranial embolectomy. RESULTS: Twenty-eight patients were treated. Median NIHSS was 22. Median time from onset to completion of treatment was 6 hours and 15 minutes. Successful recanalization with mechanical embolectomy only was achieved in 12 (43%) patients, and with additional intra-arterial tissue plasminogen activator in 18 (64%) patients. There was one procedure related technical complication, with no clinical consequence. Twelve asymptomatic and no symptomatic intracranial hemorrhages occurred. At 1 month, 9 of 8 revascularized patients and 0 of 10 nonrevascularized patients had achieved significant recovery. CONCLUSIONS: This phase 1 study shows that cerebral embolectomy with the Merci Retriever was safe and that successful recanalization could benefit a significant number of patients, even when performed in an extended 8-hour time window.