Stent-assisted coiling with LVIS Evo and HydroCoil embolic system: 1-year results of the SEALANT study

BACKGROUND: More high-quality evidence for stent-assisted coiling (SAC) of cerebral aneurysms is needed. Randomized controlled trials have shown lower recurrence with the HydroCoil Embolic System (HES) compared with bare platinum coils, and self-adjudicated LVIS Evo SAC studies have demonstrated favorable safety and technical success. The objective of the SEALANT study is to investigate the safety and effectiveness of this device combination. METHODS: SEALANT is an open-label, prospective, single-arm, multicenter study including patients with aneurysms up to a maximum size of 12 mm. The primary effectiveness endpoint was complete occlusion on digital subtraction angiography (DSA), and the primary safety endpoint was major ipsilateral stroke or neurological death. Adverse events and imaging were independently adjudicated. RESULTS: 206 patients were enrolled; 193 had follow-up imaging for outcome assessment; and 164 satisfied all criteria, were treated with both study devices (including ≥90% HES), and had DSA follow-up. The participants' mean age was 56.8±11.6 years; 65% were female. Of 212 aneurysms, 86.3% were bifurcation and 13.2% sidewall; 25.0% were previously treated and 17.9% previously ruptured; 89.6% were anterior circulation, 34.0% at the anterior communicating artery, and 30.7% at the middle cerebral artery; and 84.9% were wide-necked (neck ≥4 mm or dome/neck ratio <2). The primary effectiveness endpoint of complete occlusion was achieved in 82.1% (95% CI 76.4% to 87.9%) of aneurysms. 2.4% (95% CI 0.3% to 4.5%) of patients met the primary safety endpoint of major ipsilateral stroke or neurological death. The primary safety endpoint was significantly associated with baseline modified Rankin Scale and history of previous stroke. CONCLUSION: 1-year SEALANT results confirm the safety and effectiveness of SAC using LVIS Evo and HES. TRIAL REGISTRATION NUMBER: NCT04999423.