Introduction Preoperative simulation of flow-diverting stent (FD) deployment in aneurysm treatment could improve procedural accuracy and efficiency compared with standard planning.

Aim of Study Present interim results (first 50 patients) for first-of-its-kind, multi-centre prospective trial collecting real-world evidence on impact of CE-marked PreSize Neurovascular simulation software (Oxford Heartbeat) on clinical decision-making for FD deployment.

Methods The interventional neuroradiologist (INR) firstly plans each case, deciding device/size to use without PreSize (standard planning), then uses PreSize in real-time. Based on this, INR decides which device to use in procedure (no prescribing).

Data is collected on pre-deployment decision-making and procedure outcomes (devices used, intraoperative manipulations, simulation accuracy against post-deployment imaging). The registered study (10 hospitals) received ethics/health research approvals, supported by UK’s National Institute of Health and Care Research.

Results Average standard-selected FD length was 19.54mm vs. 18.61mm with PreSize. In 45% of cases, standard-selected FD length was different vs. PreSize-selected (mostly PreSize-selected length was shorter, by up to 20mm).

Average standard-selected FD diameter was 4.17mm vs. 4.33mm (PreSize). In 31% of cases, standard-selected FD diameter was different to PreSize-selected (mostly diameter increase, by up to 1mm). In all but 6 cases, device chosen was based directly on PreSize simulation; in only 3 cases balloon angioplasty was performed; in 88% of cases, only 1 device was deployed (1.1 device/patient); prospective simulation accuracy was evaluated 95% (mean).

Conclusion First-of-its-kind trial presents prospective data on impact of planning simulation on clinical practice, demonstrating pre-deployment real-time planning with PreSize changes device selection from current practice.