Effectiveness of Clazosentan Combined with Ozagrel for Aneurysmal Subarachnoid Hemorrhage: A Retrospective Comparative Study

Clazosentan, a selective endothelin A receptor antagonist, has recently emerged as an essential therapy for aneurysmal subarachnoid hemorrhage (aSAH) in Japan. However, evidence regarding combination therapy with adjunctive agents remains unclear. We retrospectively compared patients with aSAH treated with fasudil plus ozagrel sodium (fasudil group) and those treated with clazosentan plus ozagrel sodium (clazosentan group). The primary outcomes were angiographical vasospasm, symptomatic vasospasm (SVS), and delayed cerebral ischemia (DCI). A total of 95 patients were included (55 in the fasudil group, 40 in the clazosentan group). Although the incidence of angiographical vasospasm did not significantly differ between groups (69.1% vs. 50%, p = 0.088), the clazosentan group showed significantly lower rates of SVS (30.9% vs. 12.5%, p = 0.049) and DCI (40% vs. 20%, p = 0.046). Favorable functional outcomes (modified Rankin Scale ≤ 2) at discharge were more frequent in the clazosentan group (38.2% vs 70%, p = 0.003). Respiratory complications occurred more frequently in the clazosentan group (12.7% vs. 35%, p = 0.013). Clazosentan combined with ozagrel sodium was associated with a lower rate of SVS and DCI and a higher rate of favorable short-term functional outcome compared with a conventional fasudil-based regimen after aSAH. This combination therapy may offer additional clinical benefit, although attention to respiratory complications is warranted.