Introduction There are some misconceptions and misunderstandings regarding various implementations of what is generally called A Direct Aspiration First Pass Technique (ADAPT). Variants of the technique may result in significantly different results. We propose a modification of the ADAPT technique that promises faster procedures because of higher rates of single-pass recanalization.
Materials and methods Three years (2016–2018) of prospectively collected data on 147 consecutive thrombectomies by a single operator were reviewed retrospectively that included 68 ADAPT cases. The ratio of stent retriever cases versus ADAPT cases were compared. During this 3-year period a new catheter handling technique has been implemented, that intends to mobilize the clot before retrieval.
Video animations suggest transcatheter aspiration of a Jello-like substance via the tubing into a canister. In real life that rarely happens. Instead, the goal is to have the embolus wedged, corked into the distal tip of the catheter with the help of vacuum, then to physically remove it along with the catheter, preferably in one piece. We recognized that vacuum alone is frequently insufficient to grab, mobilize and remove the embolus in one piece. Some extra effort, or force, is needed to disrupt the adhesion of the clot to the vessel wall it is wedged in. The pulling force is limited by the vacuum lock between the catheter tip and the embolus. However, a pushing force can be stronger, achieving two goals simultaneously: disrupt the clot adhesion, and help stronger corking of the embolus into the catheter tip where the vacuum will be able to hold it stronger during removal.
The guide sheath is advanced as high as possible to provide better support. The aspiration catheter is then advanced right in front of the embolus and vacuum is turned on. The catheter is then pushed forward, beyond the original position of the embolus, during continuous aspiration. If the catheter moves forward with ease, the embolus is almost certainly mobilized and locked. The catheter can be immediately removed.
The success or failure of this forward-push technique was correlated with ADAPT ONLY success versus cross-over to stent retriever, based on our fluoroscopic videos.
Results During the 3-year period the ratio of ADAPT ONLY cases grew from 35% to 61%. The ratio of ADAPT attempts, eventually crossed over to stent retriever, decreased from 46% to 18%. Forward-push technique was used in 4, 13 and 24 cases in the 3 subsequent years. None of them (0 of 41) required crossing over to stent retriever. During the same 3 years forward-push technique was not used or failed in 26, 20 and 20 cases respectively, of them 17 (65%), 12 (60%) and 10 (50%) required crossing over to stent retrievers.
Conclusion Adhesion disruption using the forward-push technique helps to mobilize the embolus and to prepare it for a more efficient, successful removal in a single piece. Further testing, including bench-top evaluation will be needed to optimize the technique.
Disclosures L. Miskolczi: None.