Numerical Simulation of Thrombolysis in Robot-Assisted Retinal Vein Cannulation

Abstract

Robot-assisted retinal cannulation is an eye surgical procedure which can dissolve the obstruction by using robot to inject anticoagulant into occluded vessel. The current research on the critical parameters of cannulation for human is scarce because of the immature technology. Considering the influence of microneedle, this work investigated the effects of drug concentration, injection velocity, injection position, and size of clot on cannulation by theoretical analysis and finite element analysis. For finite element analysis, the multiphysics continuum model was established to demonstrate species transport and reaction which simulates the entire lytic process of the occlusive clot, and four cell zones were established to describe the generation of plasmin (PLS) with the addition of tissue-type plasminogen activator (tPA) and fibrinolysis of clot by importing subroutines into each cell zone under the conditions of constant clot size and variable size, respectively. The results imply that the most efficient value of tPA concentration is 50 nM, injection velocity is 60 mm/s for clot length of 0.1 mm, and the best position to insert the cannula is 0.5 mm in front of the thrombus. For different clot lengths of 0.1 mm to 0.6 mm, the optimal range of tPA concentration and injection velocity is from 20 nM to 70 nM and from 40 mm/s to 60 mm/s, respectively, and explores the reasonable injection position of 0.3 mm to 0.5 mm in front of clot in a vein of 100 μm. This conclusion can be used to perform robot-assisted cannulation surgery to improve fibrinolytic efficiency.

Numerical simulation and experimental validation of thrombolytic therapy for normal patient and venous isomer

“…Patients using the drug obtained much better thrombolysis than those who did not. As the thrombolytic dose increased from 50 µM to 80 µM, the final achievable thrombolytic rate increased from 14% to 18% in venous isomer (Li et al 2020;Wen et al 2018;Kumwenda et al 2021).…”

“…Jeong et al (2006) carried out a numerical analysis of the enzyme transport and flow field to predict the dissolution of thrombus under different urokinase injection regimens. Li et al (2020) simulated the dissolution process of thrombus inside the blocked blood vessel with theoretical analysis and finite element method to study the effects of different treatments, such as drug concentration and injection speed on the final treatment effect of retinal thrombus, and found a more efficient treatment method. Zhalyalov et al (2017) considered the dissolution of fibrin as the underlying logic of the dissolution of blood clots, and implemented in vitro experiments and computational biological model to study the regulation of clot formation and dissolution in time and space.…”

Numerical simulation and experimental validation of thrombolytic therapy for patients with venous isomer and normal venous valves

“…As the thrombolytic dose increased from 50 to 80 μM, the final achievable thrombolytic rate increased from 14% to 18% in venous isomer. 10,43,44 There were several assumptions and limitations in the presented numerical model. The lyophilized powder of urokinase had poor biological potency, and the maximum dissolution effect that it can be achieved was not high.…”

“…Aycock et al 9 applied numerical simulation method to study the effect of venous thrombosis filter within vein shapes from three patients, and found that venous structure has a significant impact on the performance of the filter. Li et al 10 simulated the dissolution process of thrombus inside the blocked blood vessel with theoretical analysis and finite element method to study the effects of different treatments, such as drug concentration and injection speed on the final treatment effect of retinal thrombus, and found a more efficient treatment method. Bai and Zhu 11 considered a simulation model of an arteriovenous graft in a patient with renal disease, applied the lattice Boltzmann immersion boundary (LB‐IB) framework to study the flow field under intravascular heterogeneity, and found that softer hemodialysis access materials can reduce flow disturbances.…”

Recombinant Plasminogen Activator Modified Nanoparticles for Targeting Thrombolysis in Branch Retinal Vein Occlusion

“…As early as the 1980s, rtPA was approved for the treatment of branch retinal vein occlusion and was subsequently approved for the treatment of ischemic branch retinal vein stroke (22). Until now, it is the only drug approved by the FDA for the treatment of ischemic branch retinal vein occlusion.…”