Intraoperative intra-aneurysmal pressure monitoring to individualize flow diverter therapy and optimize coil use in unruptured intracranial aneurysms

This study investigates the clinical value of using flow diverter (FD) to treat patients with unruptured intracranial aneurysms (UIAs), specifically examining changes in aneurysm sac pressure and hemodynamics before and after intraoperative FD deployment to guide the need for additional coil embolization. The aim is to explore whether FD deployment sufficiently reduces aneurysm pressure, thereby minimizing or eliminating the need for coils. A prospective cohort study enrolled 47 patients with UIAs undergoing FD treatment at the First Affiliated Hospital of Gannan Medical University from February 2023 to November 2024. Patients were divided into a pressure monitoring group (n = 23) and a control group (n = 24) based on whether real-time pressure monitoring was performed intraoperatively. The pressure monitoring group determined additional coil embolization based on changes in aneurysm sac pressure before and after FD deployment; the control group followed conventional experience-based procedures. Clinical characteristics, intraoperative parameters, coil packing density, and follow-up outcomes were compared between groups. The relationship between the dome-to-neck ratio (DNR) and pressure changes was analyzed. Following FD deployment, the intra-aneurysmal systolic pressure (ISP) decreased by 11.8% ( P = 0.041) in the pressure monitoring group, and the Intra-Aneurysmal Pressure (IAP)/Mean Arterial Pressure (MAP) ratio decreased by 5.56% ( P = 0.019). DNR was significantly higher in the pressure-increase subgroup than in the decrease subgroup (mean difference = 0.49, 95% CI: 0.05 to 0.93; P < 0.001) and positively correlated with ΔIAP/ΔMAP (r = 0.69, 95% CI: 0.39 to 0.86; P < 0.001), suggesting that higher DNR was associated with greater post-deployment pressure elevation, with DNR > 1.47 as an exploratory cutoff in this cohort. The coiling rate was numerically lower in the pressure monitoring group (34.8% vs. 54.2%; absolute difference = − 19.4%, 95% CI: − 47.2% to 8.5%; P = 0.116), with significantly lower packing density among coiled patients (mean difference = − 10.66%, 95% CI: − 12.20% to − 9.12%; P = 0.001). At short-term follow-up (median 4.5 months), no statistically significant differences were observed between groups in occlusion rates or neurological outcomes (mRS ≤ 1). In this exploratory cohort with short-term follow-up, intraoperative real-time pressure monitoring during FD deployment was feasible and was associated with reduced coil use and lower packing density among treated cases. Higher DNR was associated with greater post-FD intra-aneurysmal pressure increase; however, the DNR association and packing-density observations are exploratory and require validation in larger cohorts before clinical application.