This is a response to a JNIS publication by Orscelik et al. (2023) titled ‘Comparison of balloon guide catheter versus nonballoon guide catheter for mechanical thrombectomy in patients with distal medium vessel occlusion’.1 A clarification is made about a referenced study by Jakobek et al. (2023) titled‘The effect of distal aspiration catheter position on collateral flow in mechanical thrombectomy - an in vitro study.’

The commentary emphasises that prolonged placement of a distal aspiration catheter and a BGC could adversely affect collateral flow which in turn can affect viability of the cerebral penumbra (shifting slow progressors into fast progressors), and could also effect the rate of recanlization due to decreased back pressure. These considerations are particularly important since there is a trend towards larger bore aspiration catheters, and BGCs are already widely used. These factors are particularly relevant in prolonged …