Accelerated aspiration with Q™ catheter: An in vitro study

Abstract

Background and purpose: Thrombectomy in distal, medium vessels is a topic of increasing interest. To date, there are few in vitro studies focused on performance of ≤5F catheters in medium vessels. The purpose of this study is to compare the performance of the 3F, 4F, and 5F MIVI Neuroscience Q Catheters versus Penumbra 3F, 4F, and MicroVention Sofia 5F Catheters.

Methods: Using in vitro methods, we assessed and compared the following parameters: aspiration flow rates, clot uncorking forces, impulse, and clot ingestion. For flow rate, each aspiration catheter was immersed in a cylindrical container. Flow rate at one second was used to calculate impulse. For clot uncorking force, the force required to disengage a catheter from a simulated clot was recorded. For ingestion, we measured time to ingest soft and medium stiffness synthetic clots.

Results: The measured flow rates without a stent retriever for the Q3, Q4, and Q5 catheters were 3.54 ml/s, 5.32 ml/s, and 6.87 ml/s. The measured flow rates without a stent retriever for the 3MAX, 4MAX, and 5F Sofia were 1.46 ml/s, 2.56 ml/s, and 1.73 ml/s. The impulse calculated for one second was 26 mNs for Q5 vs 9 mNs for Sofia 5, 35 mNs for Q4 vs 15 mNs for 4Max< and 35 mNs for Q3 vs 9 mNs for 3Max. The average system ingestion for Q was significantly faster than the competitive catheters.

Conclusions: The Q catheters demonstrated higher flow rates, higher uncorking force, and faster complete clot ingestion than competitive catheters.

Keywords: Acute ischemic stroke; catheters; in-vitro methods.

Figure 1.

Schematic illustrations of (a) Q5 aspiration catheter with its single point of aspiration, sliding seal, and extension catheter design vs standard 5F aspiration catheter. (b) The set-up for flow rate measurement. Pressure on the distal tip of the catheter is higher than atmospheric pressure due to the high-water column but much lower than arterial pressure. (c) The set-up for clot uncorking force which is the force to dislodge a corked thrombus from aspiration catheter's distal tip as the catheter is retrieved.

Figure 2.

(a) Flow rate tests with and without a stent retriever. (b) Flow rate vs time graph.

Figure 3.

(a) Impulse at 1 s and (b) uncorking force (aspiration force) comparison.

Figure 4.

Clot ingestion time for Q system was significantly faster than the competitive catheters *p value <0.001. Time was stopped at 300 s and the remaining clot outside the catheter was measured.