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 ( 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

Multidetector-Row CT Angiography of Peripheral Arteries: Imaging Upper and Lower Extremity Vascular Disease

Multidetector-row CT has dramatically improved the results of computed tomography in all clinical applications, but its beneficial impact has been most striking in vascular imaging. The simplicity of acquisition and the wide availability of equipment make this modality especially suitable for routine clinical application. In this book the basic aspects of multidetector-row CT angiography are comprehensively reviewed. Individual chapters are included on technical principles, image processing techniques and contrast agent administration. All clinical applications are then discussed in depth, with lucid descriptions of the examination technique for particular clinical indications and of the findings that characterize specific diseases. Limitations and advantages in comparison with other imaging modalities are considered. A large number of high-quality black and white and color illustrations help to explain the clinical findings

CT Angiography in Pediatric Extremity Trauma: Preoperative Evaluation Prior to Reconstructive Surgery

Computed tomographic angiography (CTA) is a noninvasive modality for evaluating the vascular system and planning treatment strategies. The goal of this study was to validate the clinical utility of CTA in assessment of suspected pediatric extremity traumatic vascular injury, prior to emergent and delayed reconstructive surgery. A retrospective review was performed of all operative patients under 18 years of age who underwent multidetector-row CTA for evaluation of suspected extremity vascular injury. Parameters investigated included age, type of injury, referral source, temporal relationship between the injury and the CTA, CTA findings, operations performed, intraoperative findings, and clinical outcome. Between January 2002 and September 2005, 10 pediatric patients (6 males/4 females; mean age 8 years old, range 3–17) sustained either blunt (N = 8) or penetrating (N = 2) trauma and underwent CTA of the upper (N = 5) or lower extremities (N = 5). A total of 30% (3/10) of patients were referred from the emergency department acutely, 50% (5/10) were referred from the inpatient wards subacutely, and 20% (2/10) were referred from the outpatient clinics electively. Half (N = 5) underwent CTA to evaluate need for vascular repair, whereas half (N = 5) underwent CTA to evaluate local vasculature for flap reconstruction. Overall, 40% (4/10) of CTA findings were normal, whereas 60% (6/10) revealed traumatic vascular injuries. Pertinent nonvascular findings included soft tissue defects (60%, 6/10), fractures (40%, 4/10), and contracture deformities (20%, 2/10). In all cases, procedures were completed without complications, and intraoperative findings confirmed those from CTA. At a mean follow-up of 28 months, all injuries have healed without complications. CTA is a reliable noninvasive modality to evaluate pediatric patients with suspected traumatic extremity vascular injury and to plan treatment strategies for both vascular repair and extremity reconstruction

Vascular involvement in tuberous sclerosis

Vascular involvement in tuberous sclerosis (TS) is rare. Central and peripheral aneurysms and large and medium size arterial stenotic-occlusive disease have been reported in patients with TS. We present here three pediatric patients with TS and severe vascular abnormalities, followed by a review of the literature. The three cases include a 14-month-old girl with polycystic kidneys and cerebral tubers who had a large asymptomatic abdominal aortic aneurysm, a 2-year-old boy with multiple features of TS who had hypertension and was found to have mid-aortic syndrome with bilateral renal artery stenosis, and an 18-year-old girl with abdominal pain and TS features who had greater than 70% celiac artery stenosis. In all cases, noninvasive vascular imaging modalities were utilized for either initial diagnosis, surveillance, or both. These cases highlight the collaborative roles of the pediatric nephrologist and cardiovascular imager in the diagnosis and management of the vascular complications in TS patients. Appropriate care can only be made through a high index of suspicion

Abstract TP36: Collaterals Negate Time: Topography and Determinants of Baseline ASPECTS in STRATIS

Background: ASPECTS is routinely used to estimate ischemic lesion burden in acute stroke, yet the topography and influence of collaterals has been unexplored. Imaging selection for endovascular therapy in various time epochs may also be simplified with ASPECTS. We leveraged the large-scale registry data of STRATIS to discern the role of collaterals, time and other factors in ASPECTS topography at baseline. Methods: The STRATIS Imaging Core Lab, blind to all clinical data, independently determined ASPECTS scores and regional involvement in anterior circulation occlusions. Collateral status on baseline angiography was scored by ASITN grade. Statistical analyses described ASPECTS regional involvement or topography based on arterial occlusion site and other variables available prior to intervention, determining the influence of collaterals and time duration from onset to imaging. Results: Baseline ASPECTS (n=573) was median 8.0 (2, 10). ASPECTS regions involved were lenticular nuclei 62.3% (357/573), insula 42.2% (242/573), caudate 23.4% (134/573), M2 13.6% (78/573), M4 9.4% (54/573), M5 9.2% (53/573), M1 4.0% (23/573), M3 2.1% (12/573), M6 1.9% (11/573) and internal capsule 0.2% (1/573). Distinct patterns or topography differentiated ICA, M1 and M2 arterial occlusion sites at angiography. Overall, higher ASPECTS (7-10 vs. ≤ 6) was linked with more robust collaterals (p<0.001) and shorter duration from onset to CT (p=0.001), yet collateral grade was unrelated to time. Ordinal multivariate logistic regression on ASPECTS containing collateral grade and time (from onset to CT) as covariates demonstrated that they were significantly associated (p<0.001 and p=0.0024, respectively) with ASPECTS. Conclusions: ASPECTS topography and the extent of ischemic changes are a product of arterial occlusion site, collateral status and time duration. ASPECTS may infer collateral status, a pivotal determinant of outcome in endovascular therapy, irrespective of time from symptom onset

Abstract TP19: Thrombectomy in Medium Arteries Works for Distal Vessel Occlusions in Acute Ischemic Stroke - STRATIS

Background: Mechanical thrombectomy is established for large vessel occlusions in acute ischemic stroke, but the potential role in distal vessel occlusions of medium arteries is largely unknown. Such distal arterial segments have not been measured with respect to thrombectomy devices used during endovascular therapy. We conducted a systematic analysis of arterial size, segmental anatomy and stent retriever device performance during thrombectomy. Methods: The STRATIS angiography core lab adjudicated the exact location of the occlusion, proximal and distal device deployment, relationship to arterial bifurcations and anatomical nomenclature. Arterial diameters were measured at all of these sites. Statistical analyses examined the relationship between these variables, arterial recanalization and eTICI reperfusion. Results: Thrombectomy was performed with various device sizes, including Solitaire 4x40 in 36.3% (306/844), Solitaire 6x30 in 31.4% (265/844), Solitaire 4x20 in 26.4% (223/844), unspecified in 3.8% (32/844), Solitaire 6x20 in 1.3% (11/844) and Solitaire 4x15 in 0.8% (7/844). Arterial diameter at the occlusion site was median 2.17mm (1.40-3.59) in the distal M1, 1.67mm (0.81-2.98) in the proximal M2, 1.50mm (0.92-1.99) in the distal M2, 1.24mm (0.67-2.00) in the M3 and 1.88mm (1.49-1.94) in the P1. Considerable overlap was noted between arterial sizes at occlusion sites carrying different segmental arterial nomenclature or vessel names. During device deployment in STRATIS, median arterial diameter at the occlusion site was 2.4mm (IQR 1.9, 3.4), 2.9mm (IQR 2.2, 3.6) at the proximal stent marker and 1.4mm (IQR 1.2, 1.7) at the distal stent marker. Substantial eTICI reperfusion (2b-3) was achieved in all distal vessel occlusions (Table 1). Conclusions: Substantial reperfusion may be achieved with currently available mechanical thrombectomy devices for distal vessel occlusions in medium arteries