Effects of paroxetine, a P2X4 inhibitor, on cerebral aneurysm growth and recanalization after coil embolization: the NHO Drug for Aneurysm Study

OBJECTIVE Rupture of cerebral aneurysms has a poor prognosis, and growing aneurysms are prone to rupture. Although the number of coil embolization procedures is increasing worldwide, they are more prone to recurrence than clipping surgeries. However, there is still no drug that prevents aneurysm growth or recanalization after coil embolization. The authors have previously focused on the role of hemodynamics in cerebral aneurysm development and reported that inhibition of the P2X4 purinoceptor, by which vascular endothelial cells sense blood flow, reduced the induction and growth of aneurysms in an animal model. In this study, the authors investigated the effects of paroxetine, a P2X4 inhibitor also used as an antidepressant, on aneurysm growth and recanalization after endovascular coiling. METHODS Using the J-ASPECT Study registry, the largest comprehensive reimbursement database system for acute stroke inpatient care in Japan, the authors searched for patients incidentally taking paroxetine who were registered in the decade 2010–2019 with an unruptured cerebral aneurysm or who underwent aneurysm coiling. They calculated the growth incidence and growth rate by the person-year method and the odds ratio for recanalization within 1 year after coiling and statistically compared to controls. RESULTS Seventy-eight stroke facilities participated, and 275 patients were identified as potentially eligible. Thirty-seven patients with unruptured aneurysms and 38 after coil embolization met all eligibility criteria. They were compared with 396 control cases of unruptured aneurysms and 308 coil-placement controls. Multivariate analysis showed that paroxetine significantly reduced the incidence of aneurysm growth (number of cases with growth/person/year; incidence rate ratio [IRR] 0.24, 95% CI 0.05–0.66; p = 0.003) and the growth rate (total increase in maximum diameter in millimeters/ person/year; IRR 0.57, 95% CI 0.28–0.98; p = 0.04). Paroxetine also significantly reduced the odds of recanalization in the year after coiling (OR 0.21, 95% CI 0.05–0.95; p = 0.04). The authors then performed propensity score matching to reduce bias due to imbalances in patient characteristics between the two groups; the outcome confirmed that paroxetine significantly reduced aneurysm growth incidence (IRR 0.02, 95% CI 0.008–0.05; p < 0.0001) and growth rate (IRR 0.03, 95% CI 0.01–0.06; p < 0.0001) and the 1-year recanalization (OR 0.18, 95% CI 0.03–0.99; p = 0.04). CONCLUSIONS This observational cohort study suggests that P2X4 inhibitors such as paroxetine may be clinically applicable as prophylaxis against aneurysm rupture and postoperative recanalization.