Background: Direct aspiration thrombectomy is an increasingly utilized technique in endovascular stroke treatment that relies on vacuum and suction force to remove the clot. This report assesses the ...pressures and forces generated by different catheters and pumps. Methods: Vacuum pressures were measured using a vacuum gauge for several catheters (Stryker Catalyst6, Penumbra Ace 064, Medtronic Arc 061, and Penumbra 041) and pumps (Penumbra pump, 60-mL syringe, and the ASPIRE device). Suction forces were calculated based on pressure and catheter tip size (force = area × pressure). Vacuum pressures and forces were also assessed with a coaxial microcatheter (Rebar 18; inner diameter = 0.021 inches), mimicking a combined aspiration and stent retriever approach. Results: All catheters transmitted similar vacuum pressures, but suction force was proportionate to catheter tip area. Pump vacuum pressures were also similar, although the Penumbra pump (mean -25.63 inches Hg inHg) was slightly weaker than the syringe and the ASPIRE device (-27.04 and -27.58 inHg, respectively; p < 0.001, two-way ANOVA). A coaxial microcatheter lowered the mean vacuum pressure by only 1.2 inHg (p = 0.005), though it would theoretically create a very significant reduction in suction force if partially blocking the aspiration catheter tip area. Conclusions: All catheters transmit similar vacuum pressure, but the suction force on the clot is stronger with larger catheter tips. Coaxial microcatheters will have a minimal impact on suction force as long as they are proximal to the aspiration catheter tip. Currently available thrombectomy suction devices, including the Penumbra pump, the ASPIRE handheld pump, and the 60-mL syringe, all develop similar vacuum pressures.
This study investigates clinical outcomes after mechanical thrombectomy in adult patients with baseline Alberta Stroke Program Early CT Score (ASPECTS) of 0 to 5.
We included data from the STRATIS ...Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) from patients who underwent mechanical thrombectomy within 8 hours of symptom onset and had available ASPECTS data adjudicated by an independent core laboratory. Angiographic and clinical outcomes were collected, including successful reperfusion (modified Thrombolysis in Cerebral Infarction ≥2b), functional independence (modified Rankin Scale score 0-2), 90-day mortality, and symptomatic intracranial hemorrhage at 24 hours. Outcomes were stratified by ASPECTS scores and age.
Of the 984 patients enrolled, 763 had available ASPECTS data. Of these patients, 57 had ASPECTS of 0 to 5 with a median age of 63 years (interquartile range, 28-100), whereas 706 patients had ASPECTS of 6 to 10 with a median age of 70 years of age (interquartile range, 19-100). Ten patients had ASPECTS of 0 to 3 and 47 patients had ASPECTS of 4 to 5 at baseline. Successful reperfusion was achieved in 85.5% (47/55) in the ASPECTS of 0 to 5 group. Functional independence was achieved in 28.8% (15/52) in the ASPECTS of 0 to 5 versus 59.7% (388/650) in the 6 to 10 group (
<0.001). Mortality rates were 30.8% (16/52) in the ASPECTS of 0 to 5 and 13.4% (87/650) in the 6 to 10 group (
<0.001). sICH rates were 7.0% (4/57) in the ASPECTS of 0 to 5 and 0.9% (6/682) in the 6 to 10 group (
<0.001). No patients aged >75 years with ASPECTS of 0 to 5 (0/12) achieved functional independence versus 44.8% (13/29) of those age ≤65 (
=0.005).
Patients <65 years of age with large core infarction (ASPECTS 0-5) have better rates of functional independence and lower rates of mortality compared with patients >75 years of age. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02239640.
Acute ischemic stroke (AIS) and mechanical thrombectomy (MT) are commonly studied in vitro using cerebral artery models made of nonbiological materials. However, these models often report higher ...recanalization rates than those observed clinically, suggesting a discrepancy between experimental models and clinical settings. We believe this may be partly due to the frictional interactions between blood clots, stent retrievers (SRs), and the vessel walls. Experiments were performed to measure the coefficients of static and kinetic friction between blood clots, common nonbiological model materials, and bovine carotid arteries (CAs). Additional friction testing was performed with nitinol SRs.
Coefficients of static friction between blood clots and nonbiological materials were found to range from 0.1 to 0.2, increasing with decreasing clot hematocrit, but were significantly higher between blood clots and CAs (1.49, 0.57, and 0.46 for 0, 20, and 40% hematocrit clots, respectively). For 0% and 40% hematocrit clots, the coefficients of kinetic friction with nonbiological materials were less than 0.1, while significantly higher with CAs (0.26 and 0.23 for 0% and 40% hematocrit clots, respectively). However, no significant differences in the coefficients of kinetic friction were found between the different hematocrit clots. Testing with the nitinol SR showed no significant differences in the coefficients of kinetic friction for CAs (0.73) and silicone (0.78), suggesting that silicone could be a suitable model material for evaluating SR-vessel interactions in vitro. Overall, it is evident that discrepancies exist in the frictional forces between materials commonly used in experimental models of AIS and MT and those seen in vivo. The individual contributions of clot-artery, SR-artery, and clot-SR interactions during blood clot removal merit further investigation.
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.
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.
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 (
<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;
=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;
=0.005). Mortality did not differ between the 2 groups (15.1% for direct, 13.7% for transfer;
=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.
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.
URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640.
Current guidelines suggest treating blood pressure above 180/105 mm Hg during the first 24 hours in patients with acute ischemic stroke undergoing any form of recanalization therapy. Currently, no ...studies exist to guide blood pressure management in patients with stroke treated specifically with mechanical thrombectomy. We aimed to determine the association between blood pressure parameters within the first 24 hours after mechanical thrombectomy and patient outcomes.
We retrospectively studied a consecutive sample of adult patients who underwent mechanical thrombectomy for acute ischemic stroke of the anterior cerebral circulation at 3 institutions from March 2015 to October 2016. We collected the values of maximum, minimum, and average values of systolic blood pressure, diastolic blood pressure, and mean arterial pressures in the first 24 hours after mechanical thrombectomy. Primary and secondary outcomes were patients' functional status at 90 days measured on the modified Rankin scale and the incidence and severity of intracranial hemorrhages within 48 hours. Associations were explored using an ordered multivariable logistic regression analyses. A total of 228 patients were included (mean age 65.8±14.3; 104 males, 45.6%). Maximum systolic blood pressure independently correlated with a worse 90-day modified Rankin scale and hemorrhagic complications within 48 hours (adjusted odds ratio=1.02 1.01-1.03,
=0.004; 1.02 1.01-1.04,
=0.002; respectively) in multivariable analyses, after adjusting for several possible confounders.
Higher peak values of systolic blood pressure independently correlated with worse 90-day modified Rankin scale and a higher rate of hemorrhagic complications. Further prospective studies are warranted to identify whether systolic blood pressure is a therapeutic target to improve outcomes.
Interventional neurology is a subspecialty at the cross-section of neurology, neurosurgery, and neuroradiology that uses image-guided endovascular catheter techniques to diagnose and treat ...neurovascular disorders. Although interventional neurology techniques have existed for decades, recent landmark trials in stroke thrombectomy have catalyzed dramatic changes to the interventional neurology field, and there is rising neurology interest and representation. Unlike other neurology subspecialties, however, interventional neurology training and fellowship applications are not standardized. Thus, it can be difficult for neurology trainees to navigate this rapidly changing and multidisciplinary field. This article seeks to provide neurology residents and residency program directors with a brief overview of the modern interventional neurology field, the current fellowship application process, and tips on how neurologists can best prepare for a career in interventional neurology. To this end, we conducted a nationwide survey of interventional neurology fellowship program directors regarding training neurologists. We distill survey responses into concrete, actionable items for neurology trainees.
Background:
The indications for mechanical thrombectomy in acute ischemic stroke continue to broaden, leading neurointerventionalists to treat vessel occlusions at increasingly distal locations ...farther in time from stroke onset. Accessing these smaller vessels raises the concern of iatrogenic subarachnoid hemorrhage (SAH) owing to increasing complexity in device navigation and retrieval. This study aims to determine the prevalence of SAH following mechanical thrombectomy, associated predictors, and resulting functional outcomes using a multicenter registry and compare this with a systematic review and meta-analysis of the literature.
Methods:
Data from STRATIS (The Systematic Evaluation of Patients Treated with Neurothrombectomy Devices for Acute Ischemic Stroke) registry were analyzed dichotomized by the presence or absence of SAH after thrombectomy. Only patients with 24-h post-procedural neuroimaging were included (
n
= 841). Multivariable logistic regression was performed to identify significant predictors of SAH. A systematic review and random-effects meta-analysis was also conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) protocol.
Results:
The prevalence of post-thrombectomy SAH was 5.23% in STRATIS with 15.9% (1.84% overall) experiencing neurological decline. Distal location of vessel occlusion (OR 3.41 95% CI: 1.75–6.63,
p
< 0.001) and more than 3 device passes (OR 1.34 95% CI: 1.09–1.64,
p
= 0.01) were associated with a higher probability of SAH in contrast to a reduction with administration of intravenous tissue plasminogen activator (tPA) (OR 0.48 95% CI: 0.26–0.89,
p
= 0.02). There was a trend toward a higher discharge NIHSS (8.3 ± 8.7 vs. 5.3 ± 6.6,
p
= 0.07) with a significantly reduced proportion achieving functional independence at 90 days (modified Rankin Score 0–2: 32.5% vs. 57.8%,
p
= 0.002) in SAH patients. Pooled analysis of 10,126 patients from 6 randomized controlled trials and 64 observational studies demonstrated a prevalence of 5.85% 95% CI: 4.51–7.34%,
I
2
: 85.2%. Only location of vessel occlusion was significant for increased odds of SAH at distal sites (OR 2.89 95% CI: 1.14, 7.35).
Conclusions:
Iatrogenic SAH related to mechanical thrombectomy is more common with treatment of distally-situated occlusions and multiple device passes. While low in overall prevalence, its effect is not benign with fewer patients reaching post-procedural functional independence, particularly if symptomatic.
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