REAL-TIME VISUALIZATION OF THROMBOGENECITY IN IN VITRO BLOOD CIRCUIT USING OPTICAL COHERENCE TOMOGRAPHY: OBSERVATION OF EFFECT ON THROMBUS GROWTH BY THE DIFFERENCE IN CONNECTOR DESIGN
Yuki Matsuhashiu, Yoshiki Yamamoto, Kei Sameshima, Mitsuo Umezu, Kiyotaka Iwasaki
Center for Advanced Biomedical Sciences, TWIns, Waseda University, Japan
Background: Thrombus formation in blood contacting medical devices is an unsolved issue, especially at gaps or interphase between different materials.
Aim: The purpose of this study is to investigate the influence of different connector design, tapered and non-tapered, on thrombogenecity by real-time thrombus visualization method using optical coherence tomography (OCT).
Methods: 6 mm inner circumference and 8 mm outer circumference connecter with 1 mm tip step (connecter A) and same inner and outer circumference dimension with 30°taper angle with 100 μm tip step (connecter B) was connected to the in vitro air-contactless blood circulation circuit. Blood flow rate was set to 100 ml/min, and pressure was set to 70 mmHg. The total volume of the circuit was 50 ml. The blood contacting surfaces were coated with 2-methacryloyloxyethyl phosphorylcholine. Human whole blood, which activated clotting time was adjusted to approximately 160±20 (n=6) seconds by heparin, were circulated in the circuit for 60 minutes. OCT images were taken in a vertical direction of the interface between tube and inlet connecter, and tube and outlet connecter in ten minute intervals by OCT.
Results: Thrombus was formed in both designs of inlet and outlet parts of the connecters within the first 10 minutes of the experiment. The increasing rates of thrombus area at inlet and outlet of non-tapered and tapered connecters were 2.9 % and 0.7 %, and 4.7% and 2.3%, respectively. These results suggest that the taper design tend to increase the overall thrombogenecity rate, especially at the inlet. This result may be due to the wide flow separation caused from the taper design.
Conclusion: Thrombus was formed without regard of the connecter design, and the thrombus growth were affected by the difference in the existence of the taper.