A Simple, Reproducible Animal Model of Arterial Occlusion with Mixed Thrombus.

Background: Current animal models of thrombotic arterial occlusion are complex and difficult to perform. A more simplified model of thrombotic occlusion with angiographic endpoints and mixed thrombotic composition would be useful to assess the effectiveness of new therapeutic modalities. Methods and results: Femoral arteries in 38 New Zealand White rabbits were cannulated. The animal protocol involved denudation of one iliac artery by stripping with progressively increasing balloon size, followed by inflow arterial occlusion and the addition of thrombin. Cineangiography was performed at baseline and 10 minutes after the procedure to assess TIMI blood flow. Baseline angiography revealed normal TIMI 3 flow in all arteries. A successful angiographic endpoint of TIMI 0 or TIMI 1 blood flow was achieved in only 6 or 46% of 13 rabbits with initial use of the protocol, but was successful in 25 or 100% of a consecutive series of rabbits after the initial or repeat use of the protocol. Importantly, histologic analysis of thrombus revealed a mixture of platelets, erythrocytes, and fibrin. The mean injury index of the internal elastic lamina (IEL) was 40.7 +/- 35.16%. No correlation was found between TIMI flow change and intact IEL (R = -0.068, p > 0.5). Total procedure time was about 1 hour.
Conclusion: This simple and reproducible animal model of arterial occlusion provided a mixed thrombus that is comparable to human thrombus and thus may be useful to assess thrombolytic agents or new coronary interventional devices.