Pathogenetical subtypes of recurrent intracerebral hemorrhage: designations by SMASH-U classification system.

BACKGROUND AND PURPOSE Pathogenetic classification of intracerebral hemorrhage (ICH), using systems such as SMASH-U (structural vascular lesions, medication, cerebral amyloid angiopathy [CAA], systemic disease, hypertension, or undetermined), is important in predicting functional outcomes and mortality in patients with ICH. This study aimed to compare pathogenetic subtypes between the first and recurrent ICH. METHODS This study obtained data related to 4578 consecutive acute patients with ICH from the National Taiwan University Hospital Stroke Registry during January 1995 to December 2013. Using the SMASH-U method, patients were classified into 6 subtypes. We then analyzed the outcomes of first-ever ICH cases and pathogenetic classification of recurrent ICH. RESULTS Among 3785 patients who experienced first-ever ICH (male, 63.3%; mean age, 58.7±17.0 years), the most common cause was hypertensive angiopathy (54.9%), followed by CAA (12.2%), systemic disease (12.1%), undetermined (10.1%), structural vascular lesions (7.8%), and medication related (2.9%). In 185 cases of recurrent ICH, pathogenetic differences between the 2 ICH events were observed in 34 (18.4%) cases, most of which were CAA to hypertensive angiopathy (n=10) or vice versa (n=7). The rates of ICH recurrence were highest for systemic disease-related and CAA-related ICH at 1, 5, 10, and 15 years after the indexed ICH event. CONCLUSIONS In approximately one fifth of the recurrent patients with ICH, pathogenetic differences were observed between initial and recurrent events, particularly among those with CAA. It is possible that some patients with ICH with concomitant hypertensive angiopathy and CAA may have been categorized as CAA by the SMASH-U method.