Has the Safety of Intracranial Aneurysms Coiling Improved Results of INSTANT Study

Purpose: Coiling is still the first-line endovascular treatment for the management of intracranial aneurysms. This treatment was not evaluated in recent, large series. ARETA study has evaluated the safety and efficacy of aneurysm coiling but the recruitment took place roughly 10 years ago (2013/2015). The INSTANT study evaluated endovascular treatment of intracranial aneurysms with OPTIMA coils (Balt, Montmorency, France) in a recent period. Methods: INSTANT is a European, non-interventional, prospective study that included patients with ruptured, unruptured, or recanalized aneurysms treated with OPTIMA coils. The primary endpoint was the morbimortality of patients treated with the OPTIMA coils at 30 days. Several secondary endpoints were further evaluating safety, efficacy, and technical features. All adverse events were independently evaluated. Multiple analyses were done in order to evaluate potential factors influencing the outcomes of intracranial aneurysm treatment with coils. Results: The study population for this analysis consisted of 294 patients (56.3 ± 12.0 years, 186 women, [63.3%]) included in 18 European centers between April 2019 and September 2022. Aneurysms were sacciform in all patients, ruptured in 133/294 patients (45.2%) and unruptured or recanalized in 161/294 patients (54.8%). Aneurysm location was anterior communicating artery in 126/294 patients (42.9%), middle cerebral artery in 52/294 (17.7%), carotid siphon in 95/294 patients (32.3%) and vertebrobasilar system in 21/294 (7.1%). Overall mortality at 30 days was 0.0% in patients with unruptured aneurysms and 3.0% in those with ruptured aneurysms, all related to subarachnoid hemorrhage and its com(plications. Overall morbidity at 30 days was 1.2% in patients with unruptured aneurysms and 21.1% in those with ruptured aneurysms. None of deaths or adverse events leading to morbidity were related to the device or the procedure (0.0%). To explain the good safety results, a detailed analysis of intraoperative and postoperative complications has been conducted and is presented. Conclusion: INSTANT study shows a trend towards better safety results in aneurysm coiling (no death in the unruptured group), probably explained by several factors including improvement in devices and the way procedures are conducted, singularly management of complications.