Development of fibrinous thrombus analogue for in-vitro abdominal aortic aneurysm studies

Purpose: To develop different thrombus analogues, with mechanical properties similar to those of human fibrinous thrombus, for in-vitro aneurysm sac pressure studies. Methods: Using dynamic mechanical analysis we determined the E-modulus (| E^* |) at 0.8, 1.0, 1.5 and 3.9 Hz of ten different human fibrinous thrombus samples. We also determined loss and storage modulus to quantify the visco-elastic properties. For comparison, we measured the E-modulus (| E^*|), loss and storage modulus of gelatin, Novalyse ST8, ST14 and ST20 with and without contrast agent. Results: Mean E-modulus of the thrombus samples (SD) at 0.8, 1.0, 1.5 and 3.9 Hz was 39 (16), 37 (15), 37 (15) and 38 (14) kPa, respectively. Median (SD) storage and loss modulus were 35 (12) and 8 (4) kPa, respectively. Median (SD) tan δ was 0.25 (0.06). The E-modulus of gelatin, Novalyse ST8, ST14 and ST20 was 4, 27, 48 and 60 kPa, respectively. The E-modulus of Novalyse ST8, ST14 and ST20 mixed with contrast agent was 18, 23 and 33 kPa, respectively. Median (SD) storage, loss modulus and tan δ of the six Novalyse samples were 30 (15), 3 (1) and 0.087 (0.04), respectively. Conclusion: All the thrombus analogues, except gelatin, had an E-modulus in the range of human fibrinous thrombi. Novalyse samples are validated thrombus analogues for in-vitro aneurysm sac pressure studies. Gelatin is not appropriate to simulate fibrinous thrombus.