Clinical Results of the ANAIS Study: Mechanical Thrombectomy Using the ANA Device in Combination with a Stent Retriever in Subjects with Acute Ischemic Stroke

BACKGROUND AND PURPOSE: The ANA thrombectomy system is a funnel catheter comprising a self-expanding coated funnel that works in conjunction with a standard stent retriever and is designed to locally restrict flow and reduce clot fragmentation. The ANAIS Study to Confirm the Safety and Performance of the ANA 5F Advanced Neurovascular Access investigated the performance of the ANA funnel catheter in patients with stroke.

MATERIALS AND METHODS: Mechanical thrombectomy using the ANA device in combination with a stent retriever in subjects with acute ischemic stroke. This is a prospective, single-arm, multicenter study with blinded outcome assessment by an independent imaging Core Lab. Patients with anterior circulation stroke undergoing mechanical thrombectomy were eligible. The primary end point was successful reperfusion (expanded TICI 2b50-3) within 3 passes without rescue therapy. The safety end point combined symptomatic intracranial hemorrhage and severe adverse device effect.

RESULTS: Forty-three subjects were treated in 3 centers: mean age, 70.5 (SD, 13.1) years, 44.2% (19/43) women; median admission NIHSS score, 16.0 (range, 12.5–19.5). The primary end point was achieved in 70% (30/43) and 81% (26/32) in the intention-to-treat (ITT) and per-protocol (PP) populations, respectively. The rates of first pass expanded TICI 2c-3 were 44% (19/43) and 56% (18/32) in the ITT and PP populations, respectively. There were no severe adverse device effects/symptomatic ICH at 24 hours (0/43). When the funnel was deployed in the C1 segment of the internal carotid artery (Bouthillier Classification), the primary end point (ITT, 36%; PP, 57%) was lower than when deployed in the C2/C3 segments (ITT, 89%; PP, 100%; P < .01), or in the C4 or above segments (ITT, 71%; PP, 77%; P < .05). The primary end point was higher when continuous aspiration was applied from initiation of the retrieval maneuver (ITT, 81%; PP, 92%) compared with end-aspiration only (ITT, 36%; PP, 50%, P < .01).

CONCLUSIONS: The ANA funnel catheter achieved high rates of reperfusion and first pass success, with a good safety profile. Successful reperfusion was superior when the funnel was deployed above the C1 segment of the ICA and clot retrieval was performed under continuous aspiration.