Procalcitonin in the context of delayed cerebral ischemia after aneurysmal subarachnoid hemorrhage.

Aneurysmal subarachnoid hemorrhage (aSAH) initiates a deleterious cascade activating multiple inflammatory processes, which can contribute to delayed cerebral ischemia (DCI). Procalcitonin (PCT) is an established marker for sepsis treatment monitoring, and its time course in the context of DCI after aSAH remains unclear. The aim of this trial was to assess the predictive and confirmative value of PCT levels in the context of DCI. All patients admitted to the authors' institution with aSAH between 2014 and 2018 were prospectively screened for eligibility. Daily PCT levels were recorded alongside relevant aSAH characteristics. The predictive and confirmative values of PCT levels were assessed using a receiver operating characteristic and area under the curve (AUC) analysis. The course of PCT levels around the DCI event was evaluated in an infection-free subgroup of patients. A total of 132 patients with aSAH were included. Early PCT levels (first 3 days post-aSAH) had a low predictive value for the development of DCI (AUC 0.661, standard error [SE] 0.050; p = 0.003) and unfavorable long-term outcome (i.e., Glasgow Outcome Scale-Extended scores 1-4; AUC 0.674, SE 0.054; p = 0.003). In a subgroup analysis of infection-free patients (n = 72), PCT levels were higher in patients developing DCI (p = 0.001) and DCI-related cerebral infarction (p = 0.002). PCT concentrations increased gradually after DCI and decreased with successful intervention. In refractory cases progressing to cerebral infarction, PCT levels showed a secondary increase. Early higher PCT levels were associated with the later development of DCI and unfavorable outcome. Analysis of PCT beyond the first couple of days after hemorrhage is hampered by nosocomial infections. In infection-free patients, however, PCT levels rise during DCI and an additional increase develops in patients developing cerebral infarction. Clinical trial registration no.: NCT02142166 (clinicaltrials.gov).