Mechanical behavior of rf-treated thrombus in mechanical thrombectomy

Intra-arterial mechanical thrombectomy (IAMT) treatments for ischemic stroke have higher recanalization rate, longer treatment time window and lower risk of symptomatic intracerebral hemorrhage (sICH). However, distal embolization may occur because of loose fragments produced during maceration and engagement. The naturally coagulated thrombus is fragile and has poor binding with thrombectomy device. Improvement of thrombus-device binding can reduce fragments breaking loose during wire pull and enhance protein crosslinking in the thrombus that can increase fragmentation resistance. The effects of in-situ applied radio frequency (rf) treatment on thrombus-wire binding and interfacial fracture have been examined in this study using wire pull tests that are mechanically analogous to the embolus retrieval method in thrombectomy. Wire inserted into a thrombus was pull tested after rf-treatment. Pull test results showed that rf-treatment improves binding and reduces thrombus slippage from over 90% to less than 10%. Fracture pull test results also showed that fracture energy density of thrombus-device interface increased 40X after rf-treatment. The dramatic increase in resistance against fracture suggests that the use of in-situ rf-treatment is a promising treatment addition to reduce distal embolization and improve clinical outcomes in mechanical thrombectomy.