Early Neurological Changes and Interpretation of Clinical Grades in Aneurysmal Subarachnoid Hemorrhage

Objectives: Hunt and Hess (HH) and World Federation of Neurological Surgeons (WFNS) grades are commonly used to report clinical severity of aneurysmal subarachnoid hemorrhage (aSAH). We sought to determine the impact of early neurological changes and the timing of clinical grade assignment on the prognostication accuracy. Methods: We retrospectively reviewed a cohort of consecutive patients with aSAH who were admitted to an academic center. Patients with confirmed aneurysmal cause were included. Relevant clinical data including daily clinical grades, imaging data and functional outcome were analyzed. Favorable outcome was defined as mRS 0 to 3. Early neurological improvement (ENI) and early neurological deterioration (END) were respectively defined as any improvement or deterioration of HH grades from hospital day 1 to the earliest time from hospital day 2 to 5. Results: Of 310 patients, 24% experienced early neurological changes from hospital day 1 to 3. For each point increase in HH grades from day 1 to day 3, the odds ratio for worse outcome was 2.57 (95% CI [1.74-3.79]) and for each point decrease in HH grades from day 1 to day 3, the odds ratio for worse outcome was 0.28 (95% CI [0.17-0.47]). Receiver Operating Characteristic curve analysis revealed that clinical grades on day 3 had higher accuracy in predicting worse outcome than clinical grades on day 1. Conclusion: Early changes in neurological status can alter trajectory of hospital course and functional outcome. The prognostic accuracy of the clinical grades from hospital day 3 is significantly greater than those on admission.