Outcome after aneurysmal subarachnoid hemorrhage: The use of a graphical model in the assessment of risk factors

Introduction: Clinical assessment and CT scanning allows the identification of low, medium and high risk SAH patient groups and statistically predicts outcome. Objectives: To analyse the direct and indirect effect of adverse factors on outcome. Methods: Data from 102 consecutive prospectively identified SAH patients including risk groups, diagnostic delay, MCAV, angiographic findings, surgical events and outcome at 1 year were obtained. Using a temporal graphical chain model the associations between all variables and possible causal pathways were statistically determined. Results: Overall management mortality was 13.7% at 1 year and 71.7% had a favourable outcome. Outcome was directly associated with risk group (p = 0.0038) and rebleed (P = 0.0000). There was no significant relationship between age and risk group (p = 0.7565) and age and outcome (p = 0.8146). Pre operative WFNS grade did not predict outcome. Delayed diagnosis led to a poorer outcome (p = 0.014) - an indirect association probably due to rebleeding. Surgical problems led to a significantly poorer outcome in high risk patients. Conclusions: Risk group reliably predicted outcome. Management strategies will reduce preventable deleterious events. Future studies should stratify patients according to risk group, delay in diagnosis and rebleeding to enable a comparison of treatment protocols.