To identify predictors of medically-refractory vasospasm that necessitates endovascular treatment and evaluate its impact on discharge outcomes.

Percutaneous transluminal angioplasty or intra-arterial calcium channel blocker infusion may be necessary to treat vasospasm after aneurysmal subarachnoid hemorrhage (aSAH).

Patients with vasospasm diagnosed using transcranial Doppler or CT angiography were identified from a prospectively maintained database of aSAH admissions (2003 to 2024). Age, sex, and clinical variables with significant differences (p < 0.1) in univariate tests between patients with and without medically-refractory vasospasm were entered into a multivariable regression model to determine predictors of medically-refractory vasospasm. A separate regression model adjusted for age, sex, Hunt & Hess scores, and baseline mRS, assessed the relationship between refractory vasospasm and poor discharge functional status (mRS ≥ 3).

Of 193 patients with vasospasm (aged 56 ± 14, 67% female), 71 (37%) required endovascular therapy. Compared to medically-responsive patients, medically-refractory patients were more likely to undergo intubation (68% vs. 54%, p = 0.07), ventricular drain weaning (21% vs. 11%, p = 0.06), have higher Hunt & Hess scores (3 [IQR 2–4] vs. 2 [IQR 1–3], p < 0.01), and develop hyponatremia (serum Na < 135 mEq; 61% vs. 45%, p = 0.04). In the multivariable analysis, hyponatremia (aOR 2.18, 95% CI [1.15–4.12]) and Hunt & Hess scores (aOR 1.32, 95% CI [1.01–1.72]) independently predicted refractory vasospasm. However, medically-refractory vasospasm was not significantly associated with poor functional outcome (found in 49%) at discharge (aOR 1.55, 95% CI [0.73–3.30]).

Hunt & Hess scores and hyponatremia were predictors of vasospasm requiring endovascular therapy. However, endovascular treatment was not significantly associated with poor discharge functional status, with outcomes comparable to those of patients who did not require procedural intervention. Further study is warranted to determine whether hyponatremia management can reduce the incidence of medically-refractory vasospasm.