Hydrodynamics in Acute Ischemic Stroke Catheters Under Static and Cyclic Aspiration Conditions

Previous studies have suggested improved recanalization efficiency by using cyclic aspiration as opposed to static aspiration for mechanical thrombectomy in the treatment of acute ischemic stroke (AIS). However, there has not been an investigation into which parameters optimize this theoretical approach. Therefore, this study was designed to investigate the application of static and cyclic pressure in AIS aspiration catheters. An experimental flow system was designed to apply and measure both static and cyclic aspiration pressures in four commercial aspiration catheters. A medical aspirator and solenoid-valve were used to generate a range of applied pump pressures and cyclic valve frequencies. The measured mean and oscillatory pressure amplitudes were analyzed and compared across catheters and operating conditions. The greatest mean pressures and forces were achieved under contact-aspiration conditions using the largest diameter catheter, while the largest oscillating pressure (ΔP) and force (ΔF) values were generated in the least compliant catheter, determined to be proportional to both its inner radius and wall thickness. Furthermore, lower frequency cyclic aspiration was able to generate the largest values of ΔP and ΔF. For future investigations of cyclic aspiration AIS therapy, the best options are to use large inner diameter and low compliance catheters operating at lower cyclic frequencies to generate the greatest mean and oscillating forces on lodged thromboemboli.