Stroke Classification

Abstract

Because all history is to some extent personal, and because I have been active throughout attempts at classification, I was asked to provide a personal account of stroke subtyping and stroke registries bringing the topic up to date. ### Early Studies Clinicopathological studies during the first half of the 20th century focused on clinical signs in patients who died after stroke. Brain hemorrhages and infarcts were recognized at necropsy, but could they be separated during life? In 1935, Aring and Merritt1 analyzed 245 stroke patients studied clinically and at necropsy at the Boston City Hospital. They reported demographic, epidemiological, historical, and clinical data to determine which features differentiated thrombosis from hemorrhage. Hemorrhages (intracerebral or subarachnoid) were found in 15% of patients and 82% had ischemic infarcts called “thrombotic;” however, only 3% were considered to have cardiogenic embolic brain infarcts. The main features favoring hemorrhage were headache, vomiting, impaired consciousness, progression of the clinical neurological deficit, bloody spinal fluid, and increased spinal fluid pressure.1 This series was biased toward patients with large fatal hemorrhages and infarcts. Later, Dalsgaard-Nielsen2 in Scandinavia compiled a series of 1 000 stroke patients, and clinicians at the Mayo Clinic analyzed series of patients seen during 1945 through 19543 and from 1955 through 1969.4 These studies were based on retrospective chart reviews and all preceded CT. Infarcts were >4-times more common than hemorrhages. Infarcts were classified as embolic only if the patients had rheumatic heart disease or recent myocardial infarction. Rates of brain embolism using these criteria ranged from 3% to 8%. Nonembolic brain infarcts were assumed to be “thrombotic” and related to occlusion of brain supplying large arteries. Carotid and vertebral artery disease in the neck and lacunar infarction were not diagnoses included in any of these early studies. ### The Harvard Stroke Registry5,–,8 In 1971, Howard Bleich, a …