The H-ATOMIC Criteria for the Etiologic Classification of Patients with Intracerebral Hemorrhage

Background and Purpose There are no generally accepted criteria for the etiologic classification of intracerebral hemorrhage (ICH). For this reason, we have developed a set of etiologic criteria and have applied them to a large number of patients to determine their utility. Methods The H-ATOMIC classification includes 7 etiologic categories: Hypertension, cerebral Amyloid angiopathy, Tumour, Oral anticoagulants, vascular Malformation, Infrequent causes and Cryptogenic. For each category, the etiology is scored with three degrees of certainty: Possible(3), Probable(2) and Definite(1). Our aim was to perform a basic study consisting of neuroimaging, blood tests, and CT-angio when a numerical score (SICH) suggested an underlying structural abnormality. Combinations of > 1 etiologic category for an individual patient were acceptable. The criteria were evaluated in a multicenter and prospective study of consecutive patients with spontaneous ICH. Results Our study included 439 patients (age 70.8 +/- 14.5 years; 61.3% were men). A definite etiology was achieved in 176 (40.1% of the patients: Hypertension 28.2%, cerebral Amyloid angiopathy 0.2%, Tumour 0.2%, Oral anticoagulants 2.2%, vascular Malformation 4.5%, Infrequent causes 4.5%). A total of 7 patients (1.6%) were cryptogenic. In the remaining 58.3% of the patients, ICH was attributable to a single (n = 56, 12.7%) or the combination of >= 2 (n = 200, 45.5%) possible/probable etiologies. The most frequent combinations of etiologies involved possible hypertension with possible CAA (H(3)A(3), n = 38) or with probable CAA (H(3)A(2), n = 29), and probable hypertension with probable OA (H2O2, n = 27). The most frequent category with any degree of certainty was hypertension (H1+2+3 = 80.6%) followed by cerebral amyloid angiopathy (A(1+2+3) = 30.9%). Conclusions According to our etiologic criteria, only about 40% patients received a definite diagnosis, while in the remaining patients ICH was attributable to a single possible/probable etiology or to more than one possible/ probable etiology. The use of these criteria would likely help in the management of patients with ICH.