[Aetiological classification of ischaemic strokes: comparison of the new A-S-C-O classification and the classification by the Spanish Society of Neurology's Cerebrovascular Disease Study Group].
Sobrino García P., García Pastor A., García Arratibel A., Vicente Peracho G., Rodriguez Cruz PM., Pérez Sánchez JR., Díaz Otero F., Vázquez Alén P., Villanueva Osorio JA., Gil Núñez A.
INTRODUCTION: The A-S-C-O classification may be better than other methods for classifying ischaemic stroke by aetiology. Our aims are to describe A-S-C-O phenotype distribution (A: atherosclerosis, S: small vessel disease, C: cardiac source, O: other causes; 1: potential cause, 2: causality uncertain, 3: unlikely to be a direct cause although disease is present) and compare them to the Spanish Society of Neurology's Cerebrovascular Disease Study Group (GEECV/SEN) classification. We will also find the degree of concordance between these classification methods and determine whether using the A-S-C-O classification delivers a smaller percentage of strokes of undetermined cause. METHODS: We analysed those patients with ischaemic stroke admitted to our stroke unit in 2010 with strokes that were classified according to GEECV/SEN and A-S-C-O criteria. RESULTS: The study included 496 patients. The percentages of strokes caused by atherosclerosis and small vessel disease according to GEECV/SEN criteria were higher than the percentages for potential atherosclerotic stroke (A1) (14.1 vs. 11.9%; P=.16) and potential small vessel stroke (S1) (14.3 vs. 3%; P<.001). Cardioembolic stroke (C1) was more frequent (22.2 vs. 31%; P<.001). No differences between unusual cause of stroke and other potential causes (O1) were observed. Some degree of atherosclerosis was present in 53.5% of patients (A1, A2, or A3); 65.5% showed markers of small vessel disease (S1, S2, or S3), and 74.9% showed signs of cardioembolism (C1, C2, or C3). Fewer patients in the group without scores of 1 or 2 for any of the A-S-C-O phenotypes were identified as having a stroke of undetermined cause (46.6 vs. 29.2%; P<.001). The agreement between the 2 classifications ranged from κ<0.2 (small vessel and S1) to κ>0.8 (unusual causes and O1). CONCLUSION: Our results show that GEECV/SEN and A-S-C-O classifications are neither fully comparable nor consistent. Using the A-S-C-O classification provided additional information on co-morbidities and delivered a smaller percentage of strokes classified as having an undetermined cause.