Overlap of Diseases Underlying Ischemic Stroke
The ASCOD Phenotyping
Background and Purpose—ASCOD phenotyping (A, atherosclerosis; S, small vessel disease; C, cardiac pathology; O, other causes; and D, dissection) assigns a degree of likelihood to every potential cause (1 for potentially causal, 2 for causality is uncertain, 3 for unlikely causal but disease is present, 0 for absence of disease, and 9 for insufficient workup to rule out the disease) commonly encountered in ischemic stroke. We used ASCOD to investigate the overlap of underlying vascular diseases and their prognostic implication.
Methods—A single rater applied ASCOD in 405 patients enrolled in the Asymptomatic Myocardial Ischemia in Stroke and Atherosclerotic Disease study.
Results—A was present in 90% of patients (A1=43% and A2=15%), C in 52% (C1=23% and C2=14%), and S in 66% (S1=11% and S2=2%). On the basis of grades 1 and 2, 25% of patients had multiple underlying diseases, and 80% when all 3 grades were considered. The main overlap was found between A and C; among C1 patients, A was present in 92% of cases (A1=28%, A2=20%, and A3=44%). Conversely, among A1 patients, C was present in 47% of cases (C1=15%, C2=15%, and C3=17%). Grades for C were associated with gradual increase in the 3-year risk of vascular events, whereas risks were similar across A grades, meaning that the mere presence of atherosclerotic disease qualifies for high risk, regardless the degree of likelihood for A.
Conclusions—ASCOD phenotyping shows that the large overlap among the 3 main diseases, and the high prevalence of any form of atherosclerotic disease, reinforces the need to systematically control atherosclerotic risk factors in all ischemic strokes.
- Received March 5, 2013.
- Revision received April 26, 2013.
- Accepted May 7, 2013.
- © 2013 American Heart Association, Inc.