In Vitro Evaluation of the Polymerization Properties of N-Butyl Cyanoacrylate/Iodized Oil Mixtures for Lymphatic Interventions 

Clinical question
What are the properties of N-Butyl cyanoacrylate (NBCA)-iodized oil mixtures which affect polymerization in an in vitro model?

Take-away point
Polymerization time of NBCA/iodized oil in lymphatic fluid is prolonged by increasing iodized oil and triglyceride (TG) concentrations.

Reference
Kuetting, Daniel, et al. In Vitro Evaluation of the Polymerization Properties of N-Butyl Cyanoacrylate/Iodized Oil Mixtures for Lymphatic Interventions. Journal of Vascular and Interventional Radiology. January, 2019. Volume 30, Issue 1, 110–117.

Click here for abstract

Study design: Translational

Funding source: Self-funded or unfunded

Setting: Single institution

Summary

The polymerization characteristics of NBCA/iodized oil mixtures have been studied extensively in the vascular system and, therefore, use of glue in the vascular system is reliable and predictable. However, factors influencing NBCA/iodized oil polymerization within the lymphatic system, which differs from the vascular system in both flow and fluid composition, is not as well studied.

In order to elucidate factors affecting polymerization of NBCA/iodized oil in the lymphatic system, the authors of this study looked at varying ratios of NBCA/iodized oil in lymphatic fluid samples which differed by triglyceride content. NBCA/iodized oil mixture ratios from 1:0 to 1:7 were evaluated in 8 different lymphatic fluid samples which, apart from triglyceride content, did not differ significantly in total protein, leukocytes, sodium, potassium, calcium, or chloride levels. Fluid samples were designated as low TGs (< 50 mg/dL), n=3;
Medium TGs (100–400 mg/dL), n=3; High TGs (> 700 mg/dL), n=2. They performed a “static analysis” of polymerization time by dropping different NBCA/oil mixtures in the various lymphatic samples and evaluating time to polymerization and total polymerization time using a high-speed camera. “Dynamic analysis” of polymerization time was performed by injection of different NBCA/oil mixtures into a dynamic flow model transfusion tube containing microcoils with a constant lymph flow rate. The total polymerization time was found to be dependent on the ratio of iodized oil and the concentration of TGs. In dynamic experiments, this difference in polymerization time was found to be less pronounced but in high TG samples, polymerization took significantly longer (between 43 s at a 1:1 ratio and 467 s at a 1:7 ratio). Occlusion with a 1:7 mixture was achieved in only 1 attempt and failed in the other 4 experiments.

Commentary

Using a clever dynamic flow model, the authors were able to determine that polymerization time of NBCA/iodized oil in the lymphatic system is dependent on both the NBCA/iodized oil ratio in addition to the TG content of lymphatic fluid. This is important because, until now, the behavior of glue was only best understood in the vascular system. The use of glue, however, is important in the treatment of chylous leaks as lymphatic fluid does not have the same clotting ability of blood. Knowledge of glue polymerization characteristics in the lymphatic system is important to avoid complications. Additionally, a priori knowledge of TG content in a patient for whom thoracic duct embolization is planned may warrant initiation of nutritional therapy to mitigate the risk of treatment failure. All in all, this work represents an important step toward better understanding the optimal use of one of our increasingly-utilized embolic agents in the lymphatic system.

Post Author:
Zagum Bhatti, MD
Assistant Professor
Department of Radiology, Interventional Radiology Division
University of Texas Health Science Center at Houston, Houston, TX
@ZagumBhatti