INTERVENTIONAL TICI and Age : What ’ s the Score ?

BACKGROUND AND PURPOSE: Previous studies have suggested that advanced age predicts worse outcome following mechanical thrombectomy. We assessed outcomes from 2 recent large prospective studies to determine the association among TICI, age, and outcome. MATERIALS AND METHODS: Data from the Solitaire FR Thrombectomy for Acute Revascularization (STAR) trial, an international multicenter prospective single-arm thrombectomy study and the Solitaire arm of the Solitaire FR With the Intention For Thrombectomy (SWIFT) trial were pooled. TICI was determined by core laboratory review. Good outcome was defined as an mRS score of 0 –2 at 90 days. We analyzed the association among clinical outcome, successful-versus-unsuccessful reperfusion (TICI 2b–3 versus TICI 0 –2a), and age (dichotomized across the median). RESULTS: Two hundred sixty-nine of 291 patients treated with Solitaire in the STAR and SWIFT data bases for whom TICI and 90-day outcome data were available were included. The median age was 70 years (interquartile range, 60 –76 years) with an age range of 25– 88 years. The mean age of patients 70 years of age or younger was 59 years, and it was 77 years for patients older than 70 years. There was no significant difference between baseline NIHSS scores or procedure time metrics. Hemorrhage and device-related complications were more common in the younger age group but did not reach statistical significance. In absolute terms, the rate of good outcome was higher in the younger population (64% versus 44%, P .001). However, the magnitude of benefit from successful reperfusion was higher in the 70 years of age and older group (OR, 4.82; 95% CI, 1.32–17.63 versus OR 7.32; 95% CI, 1.73–30.99). CONCLUSIONS: Successful reperfusion is the strongest predictor of good outcome following mechanical thrombectomy, and the magnitude of benefit is highest in the patient population older than 70 years of age. ABBREVIATIONS: AIS acute ischemic stroke; NASA North American Solitaire Stent Retriever Acute Stroke; STAR Solitaire FR Thrombectomy for Acute Revascularization; SWIFT Solitaire FR With the Intention For Thrombectomy; TIMI Thrombolysis in Myocardial Infarction The clinical outcome after acute ischemic stroke is generally worse in the elderly compared with nonelderly populations. Poorer outcomes are to be expected in the elderly population in all disease states; however, the effect of a therapy may still afford a similar magnitude of benefit. Results from the Third International Stroke Trial suggest that the therapeutic effect of IV-tPA is similar or even better in the elderly population. With regard to stroke therapy, recanalization has been definitively related to good clinical outcomes. However, it has been reported in multiple studies that despite similar rates of recanalization, the elderly have higher mortality rates and poorer outcomes than younger patients following intra-arterial treatment. These studies were mostly retrospective, single-center series or used older generation devices with suboptimal reperfusion rates. Recent clinical studies demonstrating the value of mechanical thrombectomy for acute ischemic stroke (AIS) did not include a significant number of elderly patients. We performed a post Received July 1, 2015; accepted after revision September 7. From the Division of Neuroradiology (L.A.S., J.M.C., V.M.P.), Joint Department of Medical Imaging, Department of Medical Imaging, and Division of Neurosurgery (V.M.P.), Department of Surgery, Toronto Western Hospital, University Health Network, University of Toronto, Toronto, Ontario, Canada; Service of Neuroradiology (J.G.), Inselspital, University of Bern, Bern, Switzerland; Marcus Stroke and Neuroscience Center (R.G.N.), Department of Neurology, Grady Memorial Hospital, Emory University School of Medicine, Atlanta, Georgia; Department of Neuroradiology (A.B.), Hôpital Gui-de-Chauliac, Montpellier, France; Department of Neurosciences (A.D.), Hospital Universitario Germans Trias i Pujol, Barcelona, Spain; Division of Interventional Neuroradiology (R.J.), and Department of Neurology and Comprehensive Stroke Center (J.L.S.), David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California; Toshiba Stroke and Vascular Research Center (E.L.), State University of New York at Buffalo, Buffalo, New York; and Department of Radiology (B.J.B.), Erlanger Hospital at the University of Tennessee, Chattanooga, Tennessee. Please address correspondence to Vitor Mendes Pereira, MD MSc, Toronto Western Hospital and University Health Network, 3MCL-436; 399 Bathurst St, Toronto, ON, M5T 2S8, Canada; e-mail:vitormpbr@hotmail.com http://dx.doi.org/10.3174/ajnr.A4618 838 Slater May 2016 www.ajnr.org hoc analysis of 2 prospective core lab–reviewed studies assessing mechanical thrombectomy by using new-generation devices (stent retrievers) for AIS to determine whether the benefit of reperfusion was constant across age groups, including the older population. MATERIALS AND METHODS Study Design and Patient Selection We pooled data from the Solitaire FR Thrombectomy for Acute Revascularization (STAR) study and the Solitaire arm of Solitaire FR With the Intention For Thrombectomy (SWIFT) trial. Details of both studies have been previously reported. Briefly, STAR was a prospective, multicenter, single-arm study. Key inclusion criteria were presentation within 8 hours of onset of acute ischemic stroke, a proximal occlusion of an anterior circulation vessel, age between 18 and 85 years, and a National Institutes of Health Stroke Scale score of 8 –30. All patients were treated in high-volume stroke centers with a Solitaire stent retriever (Covidien, Irvine, California) through a balloon-guided catheter. SWIFT was a randomized open-label trial with blinded end point assessment comparing the Solitaire stent retriever with the Merci retriever (Concentric Medical, Mountain View, California). The study included patients 22– 85 years of age with NIHSS scores of 8 –30. Patients were either ineligible for or had not responded to intravenous rtPA. All data in the STAR and SWIFT studies were determined by an independent CT and MR imaging core laboratory, a separate angiography core laboratory, and an independent clinical events committee. The clinical events committee was responsible for the review and validation of all complications that occurred during the course of the studies and the subsequent classification of these complications related to the device or procedure. The study data were independently monitored; study management was provided by the sponsor, Covidien. Clinical outcome was determined at 90 days with the modified Rankin Scale. Reperfusion results were reported by using the Thrombolysis in Cerebral Infarction score and was defined as ranging from no reperfusion (TICI 0) to complete reperfusion (TICI 3), including partial reperfusion of TICI 2, divided in to 2a and 2b as less than and greater than 50%, respectively. This definition is different from the original one in which 2a was defined as less than two-thirds perfusion of the distal territory, and 2b, as greater than two-thirds perfusion. Intracranial hemorrhage was reported with the European Cooperative Acute Stroke Study classification. For the current study, we excluded patients from both studies for whom no TICI score or 90-day mRS was available. Data Analysis Based on the distribution of age, patients within the cohort were dichotomized into 2 groups across the median for age. We studied differences in baseline patient characteristics and treatment details between the age groups. For continuous variables, we used a t test or Wilcoxon test, and for discrete variables, a Fisher exact test. We then used multivariate logistic regression analysis to assess the effect of successful reperfusion (TICI 2b–3) versus unsuccessful reperfusion (TICI 0 –2a) on clinical outcome in each age group. Good clinical outcome at 90 days was defined as a mRS score of