Lessons Learned Over More than 500 Stroke Thrombectomies Using ADAPT With Increasing Aspiration Catheter Size.

BACKGROUND: Endovascular thrombectomy is currently the standard of care for acute ischemic stroke (AIS). Although earlier trials on endovascular thrombectomy were performed using stent retrievers, recently completed the contact aspiration vs stent retriever for successful revascularization (ASTER) and a comparison of direct aspiration versus stent retriever as a first approach (COMPASS) trials have shown the noninferiority of direct aspiration. OBJECTIVE: To report the largest experience with ADAPT thrombectomy and compare the impact of advancement in reperfusion catheter technologies on outcomes. METHODS: We reviewed a retrospective database of AIS patients who underwent ADAPT thrombectomy between January 2013 and November 2017 at the Medical University of South Carolina. Demographics and baseline characteristics, technical variables, and radiological and clinical outcomes were reviewed. RESULTS: Among 510 patients (mean age: 67.7, 50.6% females), successful recanalization at first pass was achieved in 61.8%, and with aspiration only in 77.5%. Mean procedure time was 27.4 min, and the rate of good outcomes (mRS 0-2) at 90 d was 42.9%. The rate of recanalization with aspiration only was significantly higher, and procedure time was significantly lower in patients treated with larger catheters (ACE 064 and ACE 068) compared to smaller catheters (5 MAX and ACE, P < .05). There were no differences in complication rates or postoperative parenchymal hemorrhage across groups (P > .05); however, use of ACE 068 was an independent predictor of good outcomes at 90 d on multivariate regression analysis (odds ratio = 1.6, P < .05). CONCLUSION: Refinement of ADAPT thrombectomy by incorporating reperfusion catheters with higher inner diameters and thus higher aspiration forces is associated with better outcomes, shorter procedure times, and lower likelihood of using additional devices without impacting complication rates.

Technical and Clinical Outcomes After Thrombectomy for the Various Segments of the Middle Cerebral Artery.

BACKGROUND: After showing the success of mechanical thrombectomy (MT) in treating large-vessel occlusion stroke, the target population has been expanded to include patients with smaller and more distal vessels including the M2 segment of the middle cerebral artery. We compared the procedural and clinical outcomes of patients undergoing MT using direct aspiration (ADAPT [A Direct Aspiration at first Pass Technique]) between superior or inferior divisions of M2 and M1. METHODS: We retrospectively reviewed a database of patients undergoing MT between June 2013 and July 2018 at our center for clinical and procedural variables. Patients with isolated M1 or M2 occlusions were included. M2 occlusions were classified into superior and inferior divisions. Functional outcomes were collected at 90 days. RESULTS: A total of 205 patients with M1, 65 with M2 superior division (middle cerebral artery M2 superior segment [M2S]), and 57 with inferior division (middle cerebral artery M2 inferior segment [M2I]) stroke were included. M1 and M2S patients had comparable National Institutes of Health Stroke Scale score at presentation, but higher than M2I (P < 0.01). Compared with M1, M2 occlusions had longer procedure times and required more aspiration attempts (P < 0.05). M2S thrombectomy had a significantly lower rate of successful recanalization (P < 0.05). Rates of good outcome (modified Rankin Scale score 0-2) were 46% in M1, 34% in M2S, and 44% in M2I, and postprocedural hemorrhage rates were comparable between groups. On multivariate analysis, M2S occlusion was associated with longer procedure times, lower odds of good outcomes, and lower TICI recanalization scores (P < 0.05) compared with M1. CONCLUSIONS: ADAPT is safe and effective in M2 stroke. The procedural success and efficacy of ADAPT in M2 stroke are influenced by the anatomic division with less favorable clinical and technical outcomes in the M2S division.

Development of a high resolution MRI intracranial atherosclerosis imaging phantom.

BACKGROUND AND PURPOSE: Currently, there is neither a standard protocol for vessel wall MR imaging of intracranial atherosclerotic disease (ICAD) nor a gold standard phantom to compare MR sequences. In this study, a plaque phantom is developed and characterized that provides a platform for establishing a uniform imaging approach for ICAD. MATERIALS AND METHODS: A patient specific injection mold was 3D printed to construct a geometrically accurate ICAD phantom. Polyvinyl alcohol hydrogel was infused into the core shell mold to form the stenotic artery. The ICAD phantom incorporated materials mimicking a stenotic vessel and plaque components, including fibrous cap and lipid core. Two phantoms were scanned using high resolution cone beam CT and compared with four different 3 T MRI systems across eight different sites over a period of 18 months. Inter-phantom variability was assessed by lumen dimensions and contrast to noise ratio (CNR). RESULTS: Quantitative evaluation of the minimum lumen radius in the stenosis showed that the radius was on average 0.80 mm (95% CI 0.77 to 0.82 mm) in model 1 and 0.77 mm (95% CI 0.74 to 0.81 mm) in model 2. The highest CNRs were observed for comparisons between lipid and vessel wall. To evaluate manufacturing reproducibility, the CNR variability between the two models had an average absolute difference of 4.31 (95% CI 3.82 to 5.78). Variation in CNR between the images from the same scanner separated by 7 months was 2.5-6.2, showing reproducible phantom durability. CONCLUSIONS: A plaque phantom composed of a stenotic vessel wall and plaque components was successfully constructed for multicenter high resolution MRI standardization.

Effects of Spaceflight on Astronaut Brain Structure as Indicated on MRI.

BACKGROUND: There is limited information regarding the effects of spaceflight on the anatomical configuration of the brain and on cerebrospinal fluid (CSF) spaces. METHODS: We used magnetic resonance imaging (MRI) to compare images of 18 astronauts' brains before and after missions of long duration, involving stays on the International Space Station, and of 16 astronauts' brains before and after missions of short duration, involving participation in the Space Shuttle Program. Images were interpreted by readers who were unaware of the flight duration. We also generated paired preflight and postflight MRI cine clips derived from high-resolution, three-dimensional imaging of 12 astronauts after long-duration flights and from 6 astronauts after short-duration flights in order to assess the extent of narrowing of CSF spaces and the displacement of brain structures. We also compared preflight ventricular volumes with postflight ventricular volumes by means of an automated analysis of T1-weighted MRIs. The main prespecified analyses focused on the change in the volume of the central sulcus, the change in the volume of CSF spaces at the vertex, and vertical displacement of the brain. RESULTS: Narrowing of the central sulcus occurred in 17 of 18 astronauts after long-duration flights (mean flight time, 164.8 days) and in 3 of 16 astronauts after short-duration flights (mean flight time, 13.6 days) (P<0.001). Cine clips from a subgroup of astronauts showed an upward shift of the brain after all long-duration flights (12 astronauts) but not after short-duration flights (6 astronauts) and narrowing of CSF spaces at the vertex after all long-duration flights (12 astronauts) and in 1 of 6 astronauts after short-duration flights. Three astronauts in the long-duration group had optic-disk edema, and all 3 had narrowing of the central sulcus. A cine clip was available for 1 of these 3 astronauts, and the cine clip showed upward shift of the brain. CONCLUSIONS: Narrowing of the central sulcus, upward shift of the brain, and narrowing of CSF spaces at the vertex occurred frequently and predominantly in astronauts after long-duration flights. Further investigation, including repeated postflight imaging conducted after some time on Earth, is required to determine the duration and clinical significance of these changes. (Funded by the National Aeronautics and Space Administration.).