Abstract W P374: Population-Based Eligibility for a Stroke Prevention Trial Evaluating Novel Anticoagulants and Embolic Strokes of Uncertain Etiology: Similar Eligibility as for IV Rt-PA

Abstract

Introduction: The RESPECT-ESUS trial is proposed to evaluate the best stroke prevention strategy for patients with strokes of uncertain etiology. This trial will compare a novel anticoagulant with antiplatelet agents to prevent recurrent stroke among cryptogenic stroke patients. We sought to evaluate the eligibility for this trial within a large, biracial population representative of the US. Methods: All adult ischemic stroke patients in 2010 among residents of the 5-county Greater Cincinnati/Northern Kentucky region (population 1.3 million) were ascertained from all local hospitals via ICD-9 codes 430-436. Inclusion and exclusion criteria supplied by the corporate sponsor as of 6/30/14 were applied to the ischemic stroke population. Per trial protocol, a complete workup was defined as brain and both intra- and extracranial vascular imaging, ECHO, telemetry, and EKG. Results: Of 1894 ischemic stroke patients without hemorrhagic transformation who survived the hospital stay (and not sent to hospice), 138 (7.4%) would have been eligible for RESPECT-ESUS. Inclusion and exclusion criteria are listed in the Table. If we were to assume that every stroke patient received a complete workup and no further etiologies were identified, the “hypothetical” eligibility could be as high as 18.7%. Discussion: We found that the potential eligibility for the RESPECT-ESUS trial to be low, and in fact is similar to population-based estimates of rt-PA eligibility (6%-8%). Extrapolation of eligibility across the US would be further limited by presentation to an enrolling center and consent refusal rates. Our estimates are based on information obtained during hospitalization, which may over- or underestimate eligibility within the 3-6 month post-event enrollment window. It is likely that centers that participate in the trial will have more complete diagnostic workups, which was a major exclusion in our population, especially the requirement for intracranial vascular imaging.