Twelve-year single critical care center experience of nicardipine prolonged-release implants in patients with subarachnoid hemorrhage: a propensity score matching analysis

OBJECTIVE: To develop a nicardipine prolonged-release implant (NPRI) to prevent cerebral vasospasm in patients with subarachnoid hemorrhage in 1999, which may be used during craniotomy, and report the results of our recent 12-year single critical care center experience. METHODS: Of 432 patients with aneurysmal subarachnoid hemorrhage treated between 2007 and 2019, 291 were enrolled. 97 Patients were aged >70 years (33%), 194 were female (67%), 138 were World Federation of Neurological Societies grades 1, 2, and 3 (47%), 218 were Fisher group 3 (75%), and 243 had an anterior circulation aneurysm (84%). Using a propensity score matching method for these five factors, the severity of cerebral vasospasm, occurrence of delayed cerebral infarction, and modified Rankin Scale (mRS) score at discharge were analyzed. RESULTS: One hundred patients each with or without NPRI were selected, and the ratios of coil/clip were 0/100 and 88/12, respectively. Cerebral vasospasm and delayed cerebral infarction were both significantly less common in the NPRI group (p=0.004, OR=0.412 (95% CI 0.223 to 0.760) and p=0.005, OR=0.272 (95% CI 0.103 to 0.714, respectively); a significant difference was seen in the mRS score at discharge by Fisher's exact test (p=0.0025). A mRS score of 6 (dead) was less common in the group with NPRI, and mRS scores of 0 and 1 were also less common. No side effects were seen. CONCLUSIONS: NPRIs significantly reduced the occurrence of cerebral vasospasm and delayed cerebral infraction without any side effects. The NPRI and non-NPRI groups showed different patterns of short-term outcomes in the single critical care center, which might have been due to selection bias and patient characteristics. Differences in outcomes may become clear in comparisons with patients treated by craniotomy.