Prophylactic balloon angioplasty fails to prolong the patency of expanded polytetrafluoroethylene arteriovenous grafts: Results of a prospective randomized study

AbstractPurpose: Maintenance of hemodialysis access grafts represents an enormous social and clinical problem. Current grafts and graft salvage techniques are inadequate. Consequently, there has been increasing interest in the use of minimally invasive catheter techniques to prophylactically treat stenoses in functioning arteriovenous grafts. Prophylactic balloon angioplasty has been widely suggested as prolonging assisted primary patency. We have performed a prospective randomized trial to compare patients who underwent percutaneous transluminal angioplasty (PTA) for graft stenoses >50% with a control group that received no intervention. Our hypothesis was that to be efficacious a minimal benefit of 20% prolongation in patency would be necessary.Methods: Color flow duplex scanning was used to detect >50% stenoses in functioning expanded polytetrafluoroethylene grafts. Patients were then subjected to confirmatory angiographic evaluation. Those who had angiographic stenoses >50% were randomized to balloon angioplasty or observation. Patients were followed-up with duplex scanning every 2 months. Statistical analysis was performed using the Kaplan-Meier technique. Although demographically the patient groups were well matched, there were more prior interventions and concurrent central stenoses in the treatment group. Outcomes were graft thrombosis, graft dysfunction that precluded dialysis, and six or more PTA procedures within 18 months.Results: In the treatment and observation groups, the 6-month patency rates were 69% ± 7% and 70% ± 7%, respectively. The 12-month patency rates for the treatment and observation groups were 51% ± 6% and 47% ± 4%, respectively. There was no significant difference between these two groups ( p = 0.97), with an 80% confidence limit for detection of a difference greater than 20%.Conclusions: This study demonstrates that a generic approach of PTA to treat all polytetrafluoroethylene grafts with stenoses >50% does not prolong patency and cannot be supported

Long-term Effect of Intraocular Lens vs Contact Lens Correction on Visual Acuity after Cataract Surgery during Infancy: A Randomized Clinical Trial

© 2020 American Medical Association. All rights reserved. Importance: Although intraocular lenses (IOLs) are often implanted in children, little is known whether primary IOL implantation or aphakia and contact lens correction results in better long-term visual outcomes after unilateral cataract surgery during infancy. Objective: To compare long-term visual outcomes with contact lens vs IOL correction following unilateral cataract surgery during infancy. Design, Setting, and Participants: This multicenter randomized clinical trial enrolled 114 infants with a unilateral congenital cataract who underwent cataract surgery with or without primary IOL implantation between 1 and 6 months of age. Data on long-term visual outcomes were collected when the children were age 10.5 years (July 14, 2015, to July 12, 2019) and analyzed from March 30 through August 6, 2019. Interventions: Intraocular lens implantation at the time of cataract surgery. Main Outcomes and Measures: Best-corrected visual acuity using the electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) testing protocol. Analysis was performed on an intention-to-treat basis. Results: Best-corrected visual acuity was measured at age 10.5 years for 110 of the 114 patients (96%) enrolled as infants. The participants included 58 girls (53%) and 52 boys (47%). Overall, 27 of the children (25%) had good (logMAR 0.30 [Snellen equivalent, 20/40] or better) visual acuity in the treated eye (12 [22%] in the IOL group and 15 [27%] in the aphakia group), but 50 children (44%) had a visual acuity of logMAR 1.00 (Snellen equivalent, 20/200) or worse (25 [44%] in the IOL group and 25 [44%] in the aphakia group). The median logMAR acuity in the treated eye was similar in children randomized to receive an IOL at the time of cataract extraction (0.89; interquartile range [IQR], 0.33-1.43 [Snellen equivalent, 20/159]) and those who remained aphakic (0.86; IQR, 0.30-1.46 [Snellen equivalent, 20/145]) (IQR, 0.30-1.46; P =.82). Although the overall difference in median visual acuity between the 2 groups was small, the estimate was imprecise (99% CI for the difference in medians was-0.54 to 0.47). Conclusions and Relevance: As in previous phases of the study, visual acuity outcomes were highly variable with only 27 children (25%) achieving excellent visual acuity in their treated eye and 50 children (44%) having poor vision in the treated eye. Implanting an IOL at the time of cataract extraction was neither beneficial nor detrimental to the visual outcome

Imaging Patterns of Recurrent Infarction in the Mechanisms of Early Recurrence in Intracranial Atherosclerotic Disease (MyRIAD) Study

Introduction: While much is known about recurrent clinical events in patients with intracranial atherosclerotic disease (ICAD), there is limited data on characteristics of recurrent infarcts. Methods: The NIH-funded MyRIAD prospective, observational study was designed to identify mechanisms of ischemia and predictors of recurrence in ICAD. Recurrent infarction was assessed on MRI at 6–8 weeks. We reviewed the DWI/ADC and FLAIR sequences in patients with recurrent stroke and characterized the number of infarcts, infarct location, size, and patterns based on whether they were borderzone (BZ), perforator (SC/P), cortical or territorial (C/T), and mixed. Temporal characteristics were delineated by ADC/FLAIR correlation. Results: Of the 89 patients with 6–8 weeks MRI, 22 (24.7%) had recurrent infarcts in the territory of the symptomatic artery. Recurrent infarcts were evident on DWI in 63.6% and single infarcts in 54.5%. The median recurrent infarct volume was 2.0 cm 3 compared to median index infarct volumes of 2.5 cm 3 . A mixed infarct pattern was most common (40.9%), followed by borderzone (22.7%), cortical or territorial (27.3%), while only 9.1% were in a perforator artery distribution. Amongst those with a mixed pattern, 8/9 had a borderzone distribution infarct as part of their mixed infarct pattern. Conclusion: These findings provide novel data on the characteristics of early recurrent infarcts in patients with symptomatic ICAD

Abstract 79: Mechanisms of Early Recurrence in Intracranial Atherosclerotic Disease (MyRIAD) Study: Participants, Clinical and Imaging Outcomes

Introduction: ICAD is a common cause of stroke. MyRIAD is designed to identify mechanisms of ischemia and predictors of recurrence in ICAD. Here we present the study population baseline characteristics and key outcomes. Methods: MyRIAD is an NIH/NINDS funded prospective multicenter observational study of patients with recent ( < 21 days) stroke or TIA (recurrent or with DWI) caused by IAD 50-99% without planned angioplasty/stenting. The primary outcome is ischemic stroke in the territory within 1 year of follow up; secondary outcomes are TIA at 1 year and new infarcts on MRI at 6-8 weeks. Qualifying events and clinical and imaging outcomes are centrally adjudicated. Results: MyRIAD enrolled 105 participants. The MyRIAD cohort (Table) had significant atherosclerotic risk factors and received aggressive medical therapy. Of 101 participants with clinical follow up (mean 243 + 126 days), the primary outcome of stroke in the territory at 1 year occurred in 9 (8.6%, 13.4/100 person-years), while 7 (6.7%, 10.4/100 person-years) had a TIA. A study MRI at 6-8 weeks was available for comparison to baseline MRI in 87 participants (mean time from qualifying event to follow up imaging 51 + 16 days). A new DWI/FLAIR infarct in the territory of the symptomatic vessel was noted in 22 participants (25.3%). Conclusions: MyRIAD detected an 8.6% 1-year stroke recurrence and a much higher 25.3% rate of recurrent infarction in the first weeks after qualifying stroke/TIA, emphasizing the need to develop better therapeutic interventions for ICAD

Infarct Patterns, Collaterals and Likely Causative Mechanisms of Stroke in Symptomatic Intracranial Atherosclerosis

BackgroundThere are limited data on the specific mechanisms of stroke in patients with intracranial atherosclerotic stenosis (ICAS). We undertook this study to describe infarct patterns and likely mechanisms of stroke in a large cohort of patients with ICAS, and to evaluate the relationship of these infarct patterns to angiographic features (collaterals, stenosis location and stenosis severity).MethodsWe evaluated infarct patterns in the territory of a stenotic intracranial artery on neuroimaging performed at baseline and during follow-up if a recurrent stroke occurred in patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) trial. We defined the likely mechanism of stroke (artery-to-artery embolism, perforator occlusion, hypoperfusion or mixed) according to the site of ICAS and based on the infarct patterns on neuroimaging. Collaterals were assessed using American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) grades, and stenosis severity using the WASID trial's measurement technique. We evaluated the association of infarct patterns with angiographic features using χ(2) tests.ResultsThe likely mechanisms of stroke based on the infarct patterns at baseline in the 136 patients included in the study were artery-to-artery embolism (n = 69; 50.7%), perforator occlusion (n = 34; 25%), hypoperfusion (n = 12; 8.8%) and mixed (n = 21; 15.5%). Perforator-occlusive infarcts were more frequent in the posterior circulation, and mixed patterns were more prevalent in the anterior circulation (both p &lt; 0.01). Most of the mixed patterns in the anterior circulation combined small pial or scattered multiple cortical infarcts with infarcts in border-zone regions, especially the cortical ones. Isolated border-zone infarcts were not significantly associated with a poor grading for collaterals or the severity of stenosis. Among 47 patients with a recurrent infarct during follow-up, the infarct patterns suggested an artery-to-artery embolic mechanism in 29 (61.7%).ConclusionsArtery-to-artery embolism is probably the most common mechanism of stroke in both the anterior and the posterior circulations in patients with ICAS. An extension of intracranial atherosclerosis at the site of stenosis into adjacent perforators also appears to be a common mechanism of stroke, particularly in the posterior circulation, whereas hypoperfusion as the sole mechanism is relatively uncommon. Further research is important to accurately establish the specific mechanisms of stroke in patients with ICAS, since preliminary data suggest that the underlying mechanism of stroke is an important determinant of prognosis

Abstract WP488: Imaging Correlates of Vascular Cognitive Impairment After Recent Ischemia in Intracranial Atherosclerosis: Evidence From SAMMPRIS

Background: More than 50% of individuals with recently symptomatic intracranial atherosclerotic disease (ICAD) manifest cognitive dysfunction. The imaging correlates of such cognitive impairment due to large vessel disease remain largely unknown. We examined the degree of cognitive dysfunction associated with detailed quantification of MRI DWI and FLAIR lesions at baseline in the SAMMPRIS trial. Methods: Central, blinded, adjudication of baseline MRI included measurement of DWI and FLAIR lesions and corresponding volumes. Cognitive function was assayed with the Montreal Cognitive Assessment (MoCA) score (0-30). Statistical analyses were used to describe MRI lesion characteristics and the correlation with baseline MoCA score. Results: At enrollment in SAMMPRIS, baseline DWI was available in 309/451 (69%) subjects, with FLAIR in 293/451 (65%). Baseline MoCA was median 25.0 (10-30). Chronic ischemic lesion burden on FLAIR was median 2.7 cc (0-87.0), with greater extent in those older than 60 years (p=0.03) and those on anti-thrombotics (p=0.01). DWI lesion volume (median 1.45 cc, range 0-71.84) was associated with NIHSS score (p<0.01), antithrombotic use (p=0.01) and time from qualifying event to enrollment (p=0.05). The number of DWI lesions (median 9, range 1-69) correlated (r=0.63, p<0.01) with total volume of acute infarction and was associated with more than 7 days from qualifying event (15.3 vs. 10.7, p<0.01). Chronic FLAIR lesion burden was associated with worse cognitive function or lower MoCA (r=-0.18, p=0.01) at baseline. Importantly, the volume or number of acute DWI lesions was unrelated to MoCA. Conclusions: Cognitive impairment associated with recently symptomatic intracranial atherosclerosis reflects the underlying burden of chronic, not acute, ischemia. Routine MRI, including FLAIR may inform future studies of vascular cognitive impairment in large vessel disease

Infarct Patterns, Collaterals and Likely Causative Mechanisms of Stroke in Symptomatic Intracranial Atherosclerosis

BACKGROUND: There are limited data on specific mechanisms of stroke in patients with intracranial arterial stenosis (ICAS). We undertook this study to describe infarct patterns and likely mechanisms of stroke in a large cohort of patients with ICAS, and to evaluate the relationship of infarct patterns with angiographic features (collaterals, stenosis location and stenosis severity). METHODS: We evaluated infarct patterns in the territory of a stenotic intracranial artery on neuroimaging performed at baseline and during follow-up if a recurrent stroke occurred in patients enrolled in the Warfarin-Aspirin Symptomatic Intracranial Disease (WASID) study. We defined the likely mechanism of stroke (artery-to-artery embolism, perforator occlusive, hypoperfusion, or mixed) according to the site of ICAS and based on infarct patterns on neuroimaging. Collaterals were assessed using ASITN/SIR grades and stenosis severity using WASID measurement technique. We evaluated association of infarct patterns with angiographic features using chi square tests. RESULTS: The likely mechanisms of stroke based on infarct patterns at baseline in 136 patients were: 69 artery-to-artery embolism (50.7%), 34 perforator occlusive (25%), 12 hypoperfusion (8.8%) and 21 mixed (15.5%). Perforator occlusive infarcts were more frequent in posterior circulation and mixed patterns were more prevalent in anterior circulation (both p<0.01). Most of the mixed patterns in the anterior circulation combined small pial or scattered multiple cortical infarcts with infarcts in borderzone regions, especially in cortical borderzone regions. Isolated borderzone infarcts were not significantly associated with poor collaterals or severity of stenosis. Among 47 patients with a recurrent infarct during follow-up, infarct patterns suggested an embolic artery-to-artery mechanism in 29 (61.7%). CONCLUSIONS: Artery-to-artery embolism is probably the most common mechanism of stroke in both the anterior and posterior circulations in patients with ICAS. Extension of intracranial atherosclerosis at the site of stenosis into adjacent perforators also appears to be a common mechanism of stroke, particularly in the posterior circulation, whereas hypoperfusion as the sole mechanism is relatively uncommon. Further research to accurately establish the specific mechanisms of stroke in patients with ICAS is important since preliminary data suggest that the underlying mechanism of stroke is an important determinant of prognosis