In vitro Remote Aspiration Embolectomy for the Treatment of Acute Ischemic Stroke.

Background: "Remote aspiration," using suction from the proximal internal carotid artery (ICA) to open terminus occlusions, has been reported in small case series. However, it remains unclear whether remote aspiration is feasible for middle cerebral artery occlusions in the setting of potential inflow from communicating arteries. We performed an in vitro study to assess whether suction applied at various locations proximal to an occlusion could successfully aspirate the clot.

Methods: A glass model of 4 mm inner diameter (ID) with 1 mm distal narrowing and 2 mm side branch to simulate a communicating artery was constructed. A proximal side branch was placed to simulate inflow from the proximal ICA. The impact of three different-sized catheters (ID 0.088, 0.070, and 0.056 in) on histologically different (red blood cell-cell rich, fibrin-rich, and mixed) clot analogues was tested with the catheter tip placed remotely either distal or proximal to the collateral branch. Aspiration was attempted with (1) open system (flow in both the ICA and the collateral branch, (2) flow arrest with open collateral (no flow in the ICA, but flow in the collateral branch), and (3) closed system (no flow in either the ICA or the collateral branch). The outcome was success or failure of remote aspiration.

Results: For the 0.088-in catheter, remote aspiration was successful in all conditions. For the 0.070-in catheter, remote aspiration was unsuccessful without proximal flow arrest, but was successful in all other scenarios. For the 0.056-in catheter, remote aspiration was successful only with complete flow arrest.

Conclusions: In a noncollapsible system, remote aspiration can be successfully achieved even in the setting of prominent branch arteries by using relatively large aspiration catheters. Proximal flow arrest may facilitate successful remote aspiration for some catheter sizes.