Association of basal vein of Rosenthal Variants, but not internal jugular vein stenosis at the C1 Level, with Non-Aneurysmal subarachnoid hemorrhage.

OBJECTIVE

Non-aneurysmal subarachnoid hemorrhage (NASAH) represents a subset of spontaneous subarachnoid hemorrhage (SAH) with an unclear etiology. Venous mechanisms, including internal jugular vein (IJV) stenosis and basal vein of Rosenthal (BVR) variants, have been proposed as contributing factors. We evaluated whether IJV stenosis at the C1 level is associated with NASAH and compared its predictive value with that of BVR variants.

METHODS

This retrospective case-control study evaluated spontaneous SAH patients categorized into NASAH and aneurysmal SAH (ASAH) groups based on computed tomography angiography and digital subtraction angiography findings. Clinical characteristics and functional outcomes were recorded. IJV stenosis was considered significant if there was > 50% luminal narrowing on the dominant side, or on both sides in co-dominant cases. BVR Type B or C configurations were classified as variants.

RESULTS

Overall, 104 patients (NASAH: n = 49; ASAH: n = 55) were analyzed. Baseline characteristics were similar between groups. The ASAH group had significantly worse discharge modified Rankin Scale scores (3.3 vs. 2.1, p = 0.001). BVR variants were significantly more prevalent in the NASAH group (86.4% vs. 61.1%, p = 0.005), whereas significant IJV stenosis was less prevalent in NASAH than ASAH (26.8% vs. 51.0%, p = 0.019). Multivariable analysis demonstrated that BVR variants independently predicted NASAH (adjusted odds ratio [aOR]: 5.14, 95% CI: 1.46-18.05, p = 0.011), whereas IJV stenosis did not (aOR: 0.50, 95% CI: 0.19-1.33, p = 0.166).

CONCLUSION

Static anatomical IJV stenosis at C1 does not independently predict NASAH, whereas BVR variants are significantly associated with NASAH.