More information about text formats
With great interest, we read the review by Markus on personalising the secondary prevention approach to patients with stroke ¹, published in the most recent issue of Practical Neurology. Where we are presented with clinically useful and evidence-based advice for the etiological assessment of patients with acute ischemic stroke (AIS), focusing on lacunar stroke syndromes of a non-lacunar cause, and its appropriate therapeutic management. We consider the article of great importance: a must-read for all physicians who care for patients with AIS since etiological assessment is paramount to dictate the appropriate secondary prevention measures.
The author proposes using the TOAST classification (Trial of Organon 10172 in Acute Stroke Treatment), arguing that classification systems that prime clinical syndromes over pathophysiological mechanisms are less useful. Nevertheless, the author omitted one classification which–partially–resolves the issue: the ASCOD (Atherosclerosis, Small-vessel, Cardiac embolism, Other, Dissection) system ². A comprehensive classification, which allows for more than one aetiology, while giving a degree of a causal relationship to the presence of each category of disease (1 potential, 2 uncertain, 3 unlikely, 0 disease not detected) including incomplete assessment (9 insufficient work-up), while considering some clinical features.
The ASCOD approach permits the identification of patients with diseases that would have been left as indeterm...
The ASCOD approach permits the identification of patients with diseases that would have been left as indeterminate with other classification systems, thus increasing the risk of stroke because of inadequate secondary prevention. Comparisons with other classification systems have shown that ASCO (the predecessor of ASCOD) allows for more than one cause of stroke, with a larger proportion of atherosclerosis and lower of indeterminate and small vessel disease with the potential to magnify cardiac embolism thus leading to overtreatment ³, but with a recurrence risk strongly tied to aetiology regardless of the classification system used ⁴.
However, both of the above mentioned-comparisons have a flaw: they used ASCO as a dichotomic variable, which is not, and is precisely the advantage of ASCOD, that allows individualizing secondary prevention approaches for the most likely aetiology without discarding other possible etiologies, thus decreasing the proportion of indeterminate strokes facilitating inclusion for clinical trials ⁵. The relevance of considering multiple etiologies this has been demonstrated by studies like AMISTAD in which concurrent intra- and extracranial atherosclerosis increased the risk of major adverse cardiovascular events ⁶, and the secondary analysis of SOCRATES, which demonstrated ticagrelor to be superior to aspirin in patients with atherosclerosis regardless of causal link ⁷.
Bottom line, the critical issue is to assess patients with AIS to detect the most likely aetiology responsible for the stroke, without losing sight of possible comorbidities and regardless of the classification system used. In our Hospital, we use ASCOD since it allows neurology residents to consider all potential etiologies, but each centre should individualize to its specific needs.
1. Markus H. Personalising secondary prevention: different treatments for different strokes. Practical Neurology Published Online First: 04 September 2019 doi: 10.1136/practneurol-2018-002006
2. Amarenco P, Bogousslavsky J, Caplan LR, et al. The ASCOD phenotyping of ischemic stroke (Updated ASCO Phenotyping). Cerebrovasc Dis 2013;36(1):1-5. doi: 10.1159/000352050
3. Shang W, Liu J. Stroke subtype classification: a comparative study of ASCO and modified TOAST. J Neurol Sci 2012;314(1-2):66-70. doi: 10.1016/j.jns.2011.10.029
4. Arsava EM, Helenius J, Avery R, et al. Assessment of the Predictive Validity of Etiologic Stroke Classification. JAMA Neurol 2017;74(4):419-26. doi: 10.1001/jamaneurol.2016.5815
5. Sirimarco G, Lavallee PC, Labreuche J, et al. Overlap of diseases underlying ischemic stroke: the ASCOD phenotyping. Stroke 2013;44(9):2427-33. doi: 10.1161/STROKEAHA.113.001363
6. Hoshino T, Sissani L, Labreuche J, et al. Prevalence of Systemic Atherosclerosis Burdens and Overlapping Stroke Etiologies and Their Associations With Long-term Vascular Prognosis in Stroke With Intracranial Atherosclerotic Disease. JAMA Neurol 2018;75(2):203-11. doi: 10.1001/jamaneurol.2017.3960
7. Amarenco P, Albers GW, Denison H, et al. Efficacy and safety of ticagrelor versus aspirin in acute stroke or transient ischaemic attack of atherosclerotic origin: a subgroup analysis of SOCRATES, a randomised, double-blind, controlled trial. Lancet Neurol 2017;16(4):301-10. doi: 10.1016/S1474-4422(17)30038-8