Comparison of the Efficacy and Safety of Two Dosing Protocols for Ultrasound Guided Thrombin Injection in Patients with Iatrogenic Femoral Pseudoaneurysms.

Objective: Ultrasound guided thrombin injection (UGTI) is a minimally invasive method of treatment for iatrogenic post-catheterisation femoral pseudoaneurysms (psAs). The optimal dosing protocol for UGTI has not been established. The aim of the study was to compare the success and complication rates between two different dosing protocols (the most commonly used "standard dose protocol" and the "low dose protocol," which is the fractionated administration of smaller thrombin doses of up to 40 IU every 15 s) in patients with a psA with sac volume of ≥1 mL.

Methods: This was a retrospective cohort study, and the analysis was performed using a case matching approach based on propensity score. From June 2004 to August 2018, 384 patients who underwent femoral puncture for transcatheter procedures were diagnosed with femoral psA with a sac volume of ≥1 mL and qualified for UGTI. The patients' mean age was 68 (±10.6) years and there were 217 (56.5%) women. To compare protocols, 124 patients treated according to the low dose protocol were nearest neighbour matched according to their propensity score to 124 patients treated according to the standard dose protocol.

Results: The overall success rate (99.2% vs. 98.4%; p = 1) and success rate of the first UGTI attempt (87.1% vs. 86.3%; p = .85) did not differ between the low dose and standard dose groups. Complications were less common in the low dose group (7.3% vs. 16.1%; p = .03) and the median total amount of thrombin used for procedures was smaller in the low dose group (120 IU vs. 195 IU; p = .01).

Conclusions: In patients with femoral psA with sac volume of ≥1 mL, the use of the low dose protocol seemed to be equally effective as the standard dose protocol and was associated with a lower complication rate and reduced thrombin dose.