Pre-navigation balloon technique: Distal emboli protection during stent retriever thrombectomy

During stent retriever thrombectomy, a balloon guide catheter reduces distal emboli and consequently improves clinical outcomes. Because balloons are usually used before stent retrieval, these can affect the thrombus including the distal emboli while performing microcatheter navigation. This study aimed to evaluate the usefulness and safety of the pre-navigation balloon technique during microcatheter and microwire navigation. Patients who underwent stent retriever thrombectomy secondary to an anterior circulation large-artery occlusion were retrospectively evaluated. The pre-navigation balloon technique was used, and the number of retrievals, procedure time, final recanalization, presence of distal emboli, first-pass effect (FPE), symptomatic intracranial hemorrhage including procedure-related complications, and clinical outcomes at 3 months were evaluated. In total 123 patients were analyzed, and occurrence of distal emboli was lesser in the pre-navigation balloon than in the non-preballoon group (4.4% vs. 11.5%, p = 0.02). No statistical difference was found in successful recanalization, mortality, and procedure-related complications. Moreover, the pre-navigation balloon group had a higher FPE than the non-balloon group (37.8% vs. 20.5%, p = 0.004). Although no statistical difference was found in the pre-navigation balloon group, a trend toward a higher rate of good clinical outcomes was observed (mRS 0–2 at 3 months, 55.6% vs. 48.7%, p = 0.09). For ICA occlusion(n = 35), significant effects were seen in decreasing distal embolism (0(0%) vs 3(16%), p = 0.01), increasing FPE (8(50%) vs 6(32%), p = 0.003), and improving clinical outcomes (mRS 0–2 at 3 months, 9(56%) vs 7(37%), p = 0.03) in the pre-navigation balloon group. In the multivariate analysis, lesser distal embolism (0.91 [0.80–1.00], p = 0.02), higher successful recanalization (3.52 [1.11–7.03], p = 0.016), and higher FPE (3.17 [1.83–7.37], p = 0.001) secondary to the procedure was a predictor of favorable clinical outcomes. The pre-navigation balloon technique significantly reduced occurrence of distal embolism and increased the FPE. •During IA thrombectomy, distal embolism decreases blood circulation to the affected territory and blocks the collateral flow.•A balloon guide catheter (BGC) plays an important role in improved recanalization rates, first pass effect (FPE), and clinical outcomes and decreased distal embolism.•A distal embolism occurred after microwire and microcatheter navigation pr