Abstract 2456: Quantitative Analysis Of Hemorrhage Volume For Predicting Cerebral Vasospasm After Subarachnoid Hemorrhage Between Surgical Clipping And Coil Embolization

Abstract

Objective: Subarachnoid clots are important in development of delayed vasospasm after subarachnoid hemorrhage (SAH). The purpose of this study was to define the association between the subarachnoid clot volume and the incidence of symptomatic vasospasm (SV) after surgical clipping and embolization with Guglielmi detachable coils (GDCs) for aneurysmal SAH. Methods: The subjects were 155 patients with aneurysmal SAHs that were detected with a CT scan at admission and were treated by surgical clipping (Clip group, n=112) or GDC embolization (Coil group, n=43) within 72 hours of ictus between January 22, 2002 and November 22, 2009. Software-based volumetric quantification of the subarachnoid clot was performed using the voxel count method (AZE Virtual Place Fujin Raijin, AZE Ltd.). Subarachnoid clot was defined as cisternal high density areas with a Hounsfield number from 43 to 90 in the CT scan. Results: SV occurred in 24.1% and 16.3% of the patients in the Clip group (age, 63.5±12.8; male, 33.9%) and the Coil group (age, 63.0±12.6; male, 18.6%), respectively. The area under the ROC curve for subarachnoid clots for SV patients was 0.588 (95% confidence interval: 0.472-0.704; Clip group) and 0.849 (95% confidence interval: 0.714-0.985; Coil group). Using subarachnoid clot volumes of 19.6 ml (Clip group) and 32.1 ml (Coil group) as the cut-off values, the sensitivity and specificity were 89 and 39% (Clip group) and 100 and 61% (Coil group), respectively. A χ 2 test also identified that subarachnoid clots (>19.0 ml) were associated with the development of SV compared to lower blood volumes in the Clip group (≤19.0 ml, p=0.017) and that subarachnoid clots (>32.0 ml) were associated with development of SV compared to lower blood volumes in the Coil group (≤32.0 ml, p=0.03). The hemorrhage volumes of the patients with SV in the Clip group were lower than those in the Coil group at admission (37.7±21.5 vs. 58.5±23.1 ml, p=0.034), on the day after the operation (16.5±14.6 vs. 38.3±17.4 ml, p=0.002), and on Day 3-10 after SAH (5.5±4.1 vs. 11.4±9.3 ml, p=0.017). The hemorrhage volume at admission did not differ significantly between the groups (Clip group: 32.5±22.9 ml, Coil group: 32.8±22.4 ml). Conclusions: A threshold of cisternal hemorrhage volume (>19.0 ml in the Clip group and >32.0 ml in the Coil group) may exist above which patients are very likely to develop SV. Aneurysm surgery itself may be harmful to the brain (brain retraction, use of a temporary clip, and mechanical manipulation of cerebral arteries) and can lead to the onset of cerebral vasospasm.