Proposal for the Ischemic Stroke Phenotyping System 2025: ISPS25.

Over the last 30 years, several classification systems have been proposed or used to aid in patients with subtyping ischemic stroke based on its likely etiology. Since these classification systems have been published, the field has gained more knowledge about newly reported mechanisms (eg, carotid artery web), new treatments being effective (eg, patent foramen ovale closure), and new diagnostic testing (eg, prolonged outpatient cardiac monitoring). Therefore, an updated ischemic stroke classification system is needed to integrate these advancements, enabling a more targeted workup and potentially improving treatment strategies. We propose a more comprehensive but practical and generalizable diagnostic evaluation and checklist for patients with ischemic stroke to help identify definite, probable, or possible mechanisms related to cardioembolism, large artery atherosclerosis, small vessel disease, or other determined causes (eg, hypercoagulable disorders, genetic disorders, cancer, or dissection). This expands the minimum diagnostic evaluation, leading to reclassification of patients and possibly improving secondary stroke prevention strategies. This will also create a new framework for targeted treatments and randomized trials for various ischemic stroke subtypes.