Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT

Fluoroscopic angiography of an ADAPT maneuver. Angiography shows a clot (A, white arrow) in a branch of the axillary artery with a diameter of 1.9 mm. The pressure gradient before and behind the clot is 38 mm Hg, necessitating an aspiration catheter with an inner diameter of at least 1.9F for clot removal, according to our calculations. The clot (A–D: white arrow), which is partially radiopaque, is engaged with a Sofia 5F catheter (B, black arrow). When the catheter is pulled back (C and D, black arrow), the larger portion of the clot can be removed (C and D, white arrow). However, there is fragmentation of the clot, with a small portion of the clot remaining in the vessel (C and D, arrowhead).

Correlations between minimal catheter size and vessel diameter in an average patient. Graphs represent the minimal inner catheter diameter (y-axis) needed to overcome the force that keeps a clot in its position in a vessel with a given diameter (x-axis), using ADAPT with manual aspiration in an average patient (ie, a pressure gradient of 60 mm Hg before and behind the clot). The continuous line represents the ADAPT technique without microcatheters or microwires in the aspiration catheter. Dotted lines represent the ADAPT technique with an additional microcatheter (MC) or microwire (MW) in the aspiration catheter. Gray areas under the curves correspond to catheter diameters that are not large enough for ADAPT. Given the lower pressure provided by a pump, catheters need to be approximately 1% larger than indicated in the figure when a pump instead of a syringe is used for aspiration. Black horizontal lines represent the inner diameters of various commercially available catheters: Sofia (MicroVention); AXS Catalyst 6 (CAT6; Stryker); and 5MAX, 5MAX ACE, and ACE64 (Penumbra).