Phenotypic ASCO Characterisation of Young Patients with Ischemic Stroke in the Prospective Multicentre Observational sifap1 Study

Background: The prospective, multinational European 'Stroke in Young Fabry Patients' (sifap1) study collected 4,467 patients with acute ischemic cerebrovascular events aged 18-55 years. Initially, aetiologic subtyping was performed using the TOAST classification; however, recently the phenotypic ASCO classification was presented and might be more useful to identify stroke aetiologies in young patients with a wide set of different causes. ASCO is a classification system divided in four etiologic categories (Atherosclerosis, Small vessel disease (SVD), Cardiac embolism, Other cause) with different grades of severity (1-3) and aims to characterise patients in a more comprehensive way.

Methods: We determined the ASCO score for each patient, according to prospectively collected data using the study protocol. The distribution of aetiologies was analysed with regard to concomitant causes, cryptogenic stroke and different age groups.

Results: A potentially causal aetiology (grade 1) was detected in 29.3% of 4,467 patients. Merging grades 1 and 2, a suspected aetiology was found in 54.1%. In 8.6% of patients concomitant aetiologies were identified. Most common causes were cervical arterial dissection and persistent foramen ovale, but there was also a high prevalence of large artery atherosclerosis and SVD especially in older patients of this collective. About 50% of patients had more than one finding with a lower grade of evidence (grade 3). In 14% final classification of strictly cryptogenic stroke was made.

Conclusions: This is the largest study to date, using the ASCO characterisation of ischemic stroke aetiologies. ASCO classification provides first evidence that many young patients presenting with acute stroke have concomitant stroke aetiologies associated with a substantial atherosclerosis risk profile. ASCO could be integrated in clinical routine and registry data banks, as well as large clinical trials to improve stroke documentation.