Correlation between the aneurysm morphometry and severity of subarachnoid hemorrhage in the posterior cerebral circulation.

Objective: The aim of the study was to examine the correlation between various morphometric factors of the posterior circulation aneurysms and the severity of neurologic status and radiologic extent of subarachnoid hemorrhage.

Methods: A total of 105 patients with ruptured posterior circulation aneurysms (IAs) were retrospectively analyzed in the study. The neurologic status was graded in World Federation of Neurosurgical Societies (WFNS) scale and radiological severity of subarachnoid hemorrhage was assessed in Fisher revised scale (FRS). All patients were qualified for 3-dimensional digital subtraction angiography. The following morphometric measurements were taken: dome size, dome-to-neck ratio, neck size, parent artery size; size ratio (SR), neck-to-parent artery ratio, inflow angle, and diameters of posterior circulation arteries. The univariate and the multiple regression models were used for all independent variables. The significant predictors were compared between ruptured and unruptured IAs.

Results: Univariate regression analysis revealed that inflow angle influenced grading in WFNS and that FRS grades were positively correlated with SR, dome-to-neck ratio, and inflow angle. The multiple regression model confirmed that inflow angle is an independent factor influencing WFNS scale. FRS is affected by 2 factors: SR and inflow angle. SR was more strongly correlated with FRS (r = 0.403) than with inflow angle (r = 284). The comparison of inflow angle and SR in ruptured and unruptured IAs showed a significant difference between means, 125.18 ± 21.86 versus 103.86 ± 17.7 degrees and 2.48 ± 0.46 versus 1.91 ± 0.45, respectively. The cut off points were 115.9 degrees for inflow angle and 2.31 for SR.

Conclusions: Inflow angle and SR were found to be correlated with grading in FRS, and WFNS scale was correlated with inflow angle.