Comparison of the new ASCO classification with the TOAST classification in a population with acute ischemic stroke

Abstract

Precise analysis of stroke subtypes is important for clinical treatment decisions, the prognostic evaluation of patients, as well as defining stroke populations in clinical studies. The TOAST classification is the most widely used and approved form for etiologic subtyping. Increasing knowledge about stroke mechanisms and the introduction of new diagnostic techniques have supported the promotion of the new ASCO phenotypic classification, which aims to characterize patients using different grades of evidence for stroke subtypes. We prospectively assigned 103 consecutive patients from our stroke center for subtype classification using ASCO and TOAST. Clinical features and complementary investigations were recorded according to our standardized acute stroke care protocol. Evidence grade 1 with ASCO was assessed in 12.62% for large artery disease (A), 23.30% small-vessel disease (S), 36.89% cardiac source (C) and 1.94% another cause (O). Evidence grades 1-3 were identified in 60.19% A, 75.73% S, 49.51% C, and 3.88% O. A total of 68.93% of the patients were classified in more than one category, and only 3.88% remained completely undetermined. The κ value for inter-rater agreement was 0.92-1. Using TOAST, the distribution was 9.71% A, 23.30% S, 34.95% C, 1.94% O, and 30.10% undetermined. The ASCO classification showed a good concordance with TOAST. The inter-rater agreement was high. The comprehensive character of ASCO allows the recording of important additional information. This may be helpful for a specific treatment adaptation in each individual patient and creation of different etiological profiles in view of adapted clinical trials.