Results of an European survey on the management of perimesencephalic nonaneurysmal subarachnoid hemorrhage.

Based on the current guidelines, there is no consensus on inpatient treatment including cerebral vasospasm prophylaxis and follow-up imaging for perimesencephalic nonaneurysmal subarachnoid hemorrhage (NASAH). To evaluate the daily practice of neurosurgeons within the Vascular Section of the European Association of Neurosurgical Societies (EANS) an online survey was performed from February 2023 to June 2023. Thirty-two questionnaires were answered from eighteen different countries. Most answers were provided from employees of University Hospitals (n = 27; 84.4%). Up to five NASAH cases per year were reported by 10 (31.3%), another 12 (37.4%) treat more than 20 cases. The majority of contributors (65.6%) estimate the complication rates in NASAH to be less than 2%. Inpatient monitoring was significantly influenced by the initial presentation and the distribution of blood observed in the CT scan, with significantly more patients being admitted to the intensive care unit in case 3 (p = 0.011) compared to case 1. Further, the therapeutic approaches differ in the blood pressure monitoring (p = 0.08). However, this finding did not achieve statistical significance. In case 1 and case 2 neither cerebral vasospasm prophylaxis nor transcranial doppler sonography is performed in 11 centers (34.4%) which decreases statistically significantly in case 3 (n = 2; 6.3%; p = 0.0014). This study confirms that, the amount of blood in the first native CT scan influences the treatment decision. However, clear intercontinental differences cannot be evaluated due to the small number of participants.