OUTCOME AFTER ANEURYSMAL SUBARACHNOID HEMORRHAGE - THE USE OF A GRAPHICAL MODEL IN THE ASSESSMENT OF RISK-FACTORS

In 102 consecutive prospectively identified patients with subarachnoid haemorrhage (SAH) we have analysed the severity of the initial haemor rhage and the direct and indirect effects of adverse factors on outcom e. The data we recorded included delay in diagnosis, risk groups, Dopp ler measurements, angiographic findings, surgical events and outcome a t 1 year. By using a temporal graphical chain model, the associations between all variables and possible causal pathways were statistically determined. The severity of the initial haemorrhage, as determined by means of a clinical assessment and CT scanning, allowed low-, medium- and high-risk patient groups and a statistically predictable outcome t o be identified. The overall management mortality was 13.7% at 1 year; 70.6% had a favourable outcome and 15.7% were severely disabled. Outc ome was directly associated with risk group (p = 0.0038) and rebleedin g (p = 0.0000). Delayed diagnosis led to a poorer outcome (p = 0.014) - an indirect association probably due to rebleeding. Adverse surgical events led to a significantly poorer outcome in highrisk patients. No significant relationship was found either between age and risk group (p = 0.7784) or between age and outcome (p = 0.6418). Pre operative cl inical (WFNS) grade was unreliable in predicting outcome. It is the pa rticular risk group, determined by the initial SAH, that indicates the individual patient's outcome.Management strategies can reduce prevent able adverse events such diagnostic delay and rebleeding. Future studi es should stratify patients according to risk group, delay in diagnosi s and rebleeding in order to enable a clearer comparison to be made of treatment methods.