VALIDATION OF A CLINICAL CLASSIFICATION FOR SUBTYPES OF ACUTE CEREBRAL INFARCTION

The validity of a clinical classification system was assessed for subt ypes of cerebral infarction for use in clinical trials of putative str oke therapies and clinical decision making in a population based strok e register (n = 536) compiled in Perth, Western Australia in 1989-90. The Perth Community Stroke Project (PCSS) used definitions and methodo logy similar to the Oxfordshire Community Stroke Project (OCSP) where the classification system was developed. In the PCSS, 421 cases of cer ebral infarction and primary intracerebral haemorrhage (PICH), confirm ed by brain imaging or necropsy, were classified into the subtypes tot al anterior circulation syndrome (TACS), partial anterior circulation syndrome (PACS), lacunar syndrome (LACS), and posterior circulation sy ndrome (POCS). In this relatively unselected population, relying exclu sively on LACS for a diagnosis of PICH had a very low sensitivity (6%) and positive predictive value (3%). Comparison of the frequencies and outcomes (at one year after the onset of symptoms) for each subgroup of first ever cerebral infarction in the PCSS (n 248) with the OCSP (n = 543) registers showed uniformity only for LACI. For example, there were 27% of cases of TACI in the PCSS compared with 17% in the OCSP (d ifference = 10%; 95% confidence interval (95% CI) 4% to 16%) and 15% o f cases in the PCSS compared with 24% in the OCSP were POCI (differenc e = 9%; 95% CI 3% to 15%). Case fatalities and long term handicap acro ss the subgroups were not significantly different between studies, but the frequencies of recurrent stroke were significantly greater for PO CI in the OCSP compared with the PCSS. Although this classification sy stem defines subtypes of stroke with different outcomes, simple clinic al measures-level of consciousness, paresis, disability, and incontine nce at onset-are more powerful predictors of death or dependency at on e year. It is concluded that simple clinical measures that reflect the severity of the neurological deficit should complement this classific ation system in clinical trials and practice.