Impaired Sphenoparietal Venous Drainage Is Associated With Increased Risk of Vasospasm in Aneurysmal Subarachnoid Hemorrhage

Abstract

Background Adequate venous drainage of brain parenchyma is essential to maintain cerebral perfusion and clearance of cerebrospinal fluid. The cortical vein opacification score (COVES) is a radiographic metric calculated from a computed tomography angiogram that provides a measure of venous drainage using 3 cortical veins in each hemisphere. Emerging evidence indicates that longitudinal declines in COVES correlates with poor outcomes in patients with aneurysmal subarachnoid hemorrhage (aSAH), but the clinical factors associated with a low COVES, and the relationship between COVES and other outcomes remains poorly understood. Methods We performed a single‐center retrospective analysis of 54 patients with aSAH to characterize the relationship between the COVES score and radiographic vasospasm. Results We found that patients with high‐grade aSAH (Hunt and Hess 4–5) had worse cortical venous drainage (mean total COVES±SEM, 10.2±0.2, n = 21) compared with patients with lower grade aSAH (Hunt and Hess 2–3, n = 33, 9.5±0.3, P<0.05, 2‐tailed t‐test) and that venous drainage improves at longitudinal follow‐up after discharge (mean increase in total COVES: 1.3±0.3, P<0.01). Logistic regression revealed that patients whose admission computed tomography angiogram showed impairment in sphenoparietal drainage were at the highest risk for radiographic vasospasm (odds ratio, 0.34 [95% CI, 0.13–0.84]). Conclusion These results suggest a potential mechanistic link between impaired venous drainage and radiographic vasospasm and provide the basis for further study of COVES as a prognostic tool in patients with aSAH. We found that patients with more severe presentations of aneurysmal subarachnoid hemorrhage had impairment in cortical venous drainage. Impairments in venous drainage were associated with a higher likelihood of radiographic vasospasm.